Programs & Examples On #Sar

0

Adding a UISegmentedControl to UITableView

   self.tableView.tableHeaderView = segmentedControl; 

If you want it to obey your width and height properly though enclose your segmentedControl in a UIView first as the tableView likes to mangle your view a bit to fit the width.

enter image description here enter image description here

Use NSInteger as array index

According to the error message, you declared myLoc as a pointer to an NSInteger (NSInteger *myLoc) rather than an actual NSInteger (NSInteger myLoc). It needs to be the latter.

500 Error on AppHarbor but downloaded build works on my machine

Just a wild guess: (not much to go on) but I have had similar problems when, for example, I was using the IIS rewrite module on my local machine (and it worked fine), but when I uploaded to a host that did not have that add-on module installed, I would get a 500 error with very little to go on - sounds similar. It drove me crazy trying to find it.

So make sure whatever options/addons that you might have and be using locally in IIS are also installed on the host.

Similarly, make sure you understand everything that is being referenced/used in your web.config - that is likely the problem area.

Visual Studio Code PHP Intelephense Keep Showing Not Necessary Error

Intelephense 1.3 added undefined type, function, constant, class constant, method, and property diagnostics, where previously in 1.2 there was only undefined variable diagnostics.

Some frameworks are written in a way that provide convenient shortcuts for the user but make it difficult for static analysis engines to discover symbols that are available at runtime.

Stub generators like https://github.com/barryvdh/laravel-ide-helper help fill the gap here and using this with Laravel will take care of many of the false diagnostics by providing concrete definitions of symbols that can be easily discovered.

Still, PHP is a very flexible language and there may be other instances of false undefined symbols depending on how code is written. For this reason, since 1.3.3, intelephense has config options to enable/disable each category of undefined symbol to suit the workspace and coding style.

These options are: intelephense.diagnostics.undefinedTypes intelephense.diagnostics.undefinedFunctions intelephense.diagnostics.undefinedConstants intelephense.diagnostics.undefinedClassConstants intelephense.diagnostics.undefinedMethods intelephense.diagnostics.undefinedProperties intelephense.diagnostics.undefinedVariables

Setting all of these to false except intelephense.diagnostics.undefinedVariables will give version 1.2 behaviour. See the VSCode settings UI and search for intelephense.

Typescript: Type X is missing the following properties from type Y length, pop, push, concat, and 26 more. [2740]

I had the same problem and I solved as follows define an interface like mine

export class Notification {
    id: number;
    heading: string;
    link: string;
}

and in nofificationService write

allNotifications: Notification[]; 
  //NotificationDetail: Notification;  
  private notificationsUrl = 'assets/data/notification.json';  // URL to web api 
  private downloadsUrl = 'assets/data/download.json';  // URL to web api 

  constructor(private httpClient: HttpClient ) { }

  getNotifications(): Observable<Notification[]> {    
       //return this.allNotifications = this.NotificationDetail.slice(0);  
     return this.httpClient.get<Notification[]>

(this.notificationsUrl).pipe(map(res => this.allNotifications = res))
      } 

and in component write

 constructor(private notificationService: NotificationService) {
   }

  ngOnInit() {
      /* get Notifications */
      this.notificationService.getNotifications().subscribe(data => this.notifications = data);
}

How to compare oldValues and newValues on React Hooks useEffect?

Incase anybody is looking for a TypeScript version of usePrevious:

In a .tsx module:

import { useEffect, useRef } from "react";

const usePrevious = <T extends unknown>(value: T): T | undefined => {
  const ref = useRef<T>();
  useEffect(() => {
    ref.current = value;
  });
  return ref.current;
};

Or in a .ts module:

import { useEffect, useRef } from "react";

const usePrevious = <T>(value: T): T | undefined => {
  const ref = useRef<T>();
  useEffect(() => {
    ref.current = value;
  });
  return ref.current;
};

How to install OpenJDK 11 on Windows?

  1. Extract the zip file into a folder, e.g. C:\Program Files\Java\ and it will create a jdk-11 folder (where the bin folder is a direct sub-folder). You may need Administrator privileges to extract the zip file to this location.

  2. Set a PATH:

    • Select Control Panel and then System.
    • Click Advanced and then Environment Variables.
    • Add the location of the bin folder of the JDK installation to the PATH variable in System Variables.
    • The following is a typical value for the PATH variable: C:\WINDOWS\system32;C:\WINDOWS;"C:\Program Files\Java\jdk-11\bin"
  3. Set JAVA_HOME:

    • Under System Variables, click New.
    • Enter the variable name as JAVA_HOME.
    • Enter the variable value as the installation path of the JDK (without the bin sub-folder).
    • Click OK.
    • Click Apply Changes.
  4. Configure the JDK in your IDE (e.g. IntelliJ or Eclipse).

You are set.

To see if it worked, open up the Command Prompt and type java -version and see if it prints your newly installed JDK.

If you want to uninstall - just undo the above steps.

Note: You can also point JAVA_HOME to the folder of your JDK installations and then set the PATH variable to %JAVA_HOME%\bin. So when you want to change the JDK you change only the JAVA_HOME variable and leave PATH as it is.

Loading class `com.mysql.jdbc.Driver'. This is deprecated. The new driver class is `com.mysql.cj.jdbc.Driver'

If seeing this message in Hive with new MySQL connector 8.x (MySQL metastore)

open hive-site.xml and change:

   <property>
      <name>javax.jdo.option.ConnectionDriverName</name>
      <value>com.mysql.jdbc.Driver</value>
      <description>MySQL JDBC driver class</description>
   </property>

to

   <property>
      <name>javax.jdo.option.ConnectionDriverName</name>
      <value>com.mysql.cj.jdbc.Driver</value>
      <description>MySQL JDBC driver class</description>
   </property>

How to clear Flutter's Build cache?

I tried flutter clean and that didn't work for me. Then I went to wipe the emulator's data and voila, the cached issue was gone. If you have Android Studio you can launch the AVD Manager by following this Create and Manage virtual machine. Otherwise you can wipe the emulator's data using the emulator.exe command line that's included in the android SDK. Simply follow this instructions here Start the emulator from the command line.

PackagesNotFoundError: The following packages are not available from current channels:

Have you tried:

pip install <package>

or

conda install -c conda-forge <package>

Google Colab: how to read data from my google drive?

Good news, PyDrive has first class support on CoLab! PyDrive is a wrapper for the Google Drive python client. Here is an example on how you would download ALL files from a folder, similar to using glob + *:

!pip install -U -q PyDrive
import os
from pydrive.auth import GoogleAuth
from pydrive.drive import GoogleDrive
from google.colab import auth
from oauth2client.client import GoogleCredentials

# 1. Authenticate and create the PyDrive client.
auth.authenticate_user()
gauth = GoogleAuth()
gauth.credentials = GoogleCredentials.get_application_default()
drive = GoogleDrive(gauth)

# choose a local (colab) directory to store the data.
local_download_path = os.path.expanduser('~/data')
try:
  os.makedirs(local_download_path)
except: pass

# 2. Auto-iterate using the query syntax
#    https://developers.google.com/drive/v2/web/search-parameters
file_list = drive.ListFile(
    {'q': "'1SooKSw8M4ACbznKjnNrYvJ5wxuqJ-YCk' in parents"}).GetList()

for f in file_list:
  # 3. Create & download by id.
  print('title: %s, id: %s' % (f['title'], f['id']))
  fname = os.path.join(local_download_path, f['title'])
  print('downloading to {}'.format(fname))
  f_ = drive.CreateFile({'id': f['id']})
  f_.GetContentFile(fname)


with open(fname, 'r') as f:
  print(f.read())

Notice that the arguments to drive.ListFile is a dictionary that coincides with the parameters used by Google Drive HTTP API (you can customize the q parameter to be tuned to your use-case).

Know that in all cases, files/folders are encoded by id's (peep the 1SooKSw8M4ACbznKjnNrYvJ5wxuqJ-YCk) on Google Drive. This requires that you search Google Drive for the specific id corresponding to the folder you want to root your search in.

For example, navigate to the folder "/projects/my_project/my_data" that is located in your Google Drive.

Google Drive

See that it contains some files, in which we want to download to CoLab. To get the id of the folder in order to use it by PyDrive, look at the url and extract the id parameter. In this case, the url corresponding to the folder was:

https://drive.google.com/drive/folders/1SooKSw8M4ACbznKjnNrYvJ5wxuqJ-YCk

Where the id is the last piece of the url: 1SooKSw8M4ACbznKjnNrYvJ5wxuqJ-YCk.

Issue in installing php7.2-mcrypt

@praneeth-nidarshan has covered mostly all the steps, except some:

  • Check if you have pear installed (or install):

$ sudo apt-get install php-pear

  • Install, if isn't already installed, php7.2-dev, in order to avoid the error:

sh: phpize: not found

ERROR: `phpize’ failed

$ sudo apt-get install php7.2-dev

  • Install mcrypt using pecl:

$ sudo pecl install mcrypt-1.0.1

  • Add the extention extension=mcrypt.so to your php.ini configuration file; if you don't know where it is, search with:

$ sudo php -i | grep 'Configuration File'

Can (a== 1 && a ==2 && a==3) ever evaluate to true?

I don't see this answer already posted, so I'll throw this one into the mix too. This is similar to Jeff's answer with the half-width Hangul space.

_x000D_
_x000D_
var a = 1;_x000D_
var a = 2;_x000D_
var ? = 3;_x000D_
if(a == 1 && a == 2 && ? == 3) {_x000D_
    console.log("Why hello there!")_x000D_
}
_x000D_
_x000D_
_x000D_

You might notice a slight discrepancy with the second one, but the first and third are identical to the naked eye. All 3 are distinct characters:

a - Latin lower case A
a - Full Width Latin lower case A
? - Cyrillic lower case A

The generic term for this is "homoglyphs": different unicode characters that look the same. Typically hard to get three that are utterly indistinguishable, but in some cases you can get lucky. A, ?, ?, and ? would work better (Latin-A, Greek Alpha, Cyrillic-A, and Cherokee-A respectively; unfortunately the Greek and Cherokee lower-case letters are too different from the Latin a: a,?, and so doesn't help with the above snippet).

There's an entire class of Homoglyph Attacks out there, most commonly in fake domain names (eg. wikipedi?.org (Cyrillic) vs wikipedia.org (Latin)), but it can show up in code as well; typically referred to as being underhanded (as mentioned in a comment, [underhanded] questions are now off-topic on PPCG, but used to be a type of challenge where these sorts of things would show up). I used this website to find the homoglyphs used for this answer.

Could not resolve com.android.support:appcompat-v7:26.1.0 in Android Studio new project

Your android studio may be forgot to put : buildToolsVersion "26.0.0" you need 'buildTools' to develop related design and java file. And if there is no any buildTools are installed in Android->sdk->build-tools directory then download first.

Where to declare variable in react js

Assuming that onMove is an event handler, it is likely that its context is something other than the instance of MyContainer, i.e. this points to something different.

You can manually bind the context of the function during the construction of the instance via Function.bind:

class MyContainer extends Component {
  constructor(props) {
    super(props);

    this.onMove = this.onMove.bind(this);

    this.test = "this is a test";
  }

  onMove() {
    console.log(this.test);
  }
}

Also, test !== testVariable.

cmake error 'the source does not appear to contain CMakeLists.txt'

This reply may be late but it may help users having similar problem. The opencv-contrib (available at https://github.com/opencv/opencv_contrib/releases) contains extra modules but the build procedure has to be done from core opencv (available at from https://github.com/opencv/opencv/releases) modules.

Follow below steps (assuming you are building it using CMake GUI)

  1. Download openCV (from https://github.com/opencv/opencv/releases) and unzip it somewhere on your computer. Create build folder inside it

  2. Download exra modules from OpenCV. (from https://github.com/opencv/opencv_contrib/releases). Ensure you download the same version.

  3. Unzip the folder.

  4. Open CMake

  5. Click Browse Source and navigate to your openCV folder.

  6. Click Browse Build and navigate to your build Folder.

  7. Click the configure button. You will be asked how you would like to generate the files. Choose Unix-Makefile from the drop down menu and Click OK. CMake will perform some tests and return a set of red boxes appear in the CMake Window.

  8. Search for "OPENCV_EXTRA_MODULES_PATH" and provide the path to modules folder (e.g. /Users/purushottam_d/Programs/OpenCV3_4_5_contrib/modules)

  9. Click Configure again, then Click Generate.

  10. Go to build folder

# cd build
# make
# sudo make install
  1. This will install the opencv libraries on your computer.

Pipenv: Command Not Found

In some cases of old pip version:

sudo easy_install pip
sudo pip install pipenv

iOS 11, 12, and 13 installed certificates not trusted automatically (self signed)

While writing this question, I discovered the answer. Installing a CA from Safari no longer automatically trusts it. I had to manually trust it from the Certificate Trust Settings panel (also mentioned in this question).

enter image description here

I debated canceling the question, but I thought it might be helpful to have some of the relevant code and log details someone might be looking for. Also, I never encountered the issue until iOS 11. I even went back and reconfirmed that it automatically works up through iOS 10.

I've never needed to touch that settings panel before, because any installed certificates were automatically trusted. Maybe it will change by the time iOS 11 ships, but I doubt it. Hopefully this helps save someone the time I wasted.

If anyone knows why this behaves differently for some people on different versions of iOS, I'd love to know in comments.

Update 1: Checking out the first iOS 12 beta, it looks like things remain the same. This question/answer/comments are still relevant on iOS 12.

Update 2: Same solution seems to be needed on iOS 13 beta builds as well.

Global Angular CLI version greater than local version

Run the following Command: npm install --save-dev @angular/cli@latest

After running the above command the console might popup the below message

The Angular CLI configuration format has been changed, and your existing configuration can be updated automatically by running the following command: ng update @angular/cli

ssl.SSLError: tlsv1 alert protocol version

None of the accepted answers pointed me in the right direction, and this is still the question that comes up when searching the topic, so here's my (partially) successful saga.

Background: I run a Python script on a Beaglebone Black that polls the cryptocurrency exchange Poloniex using the python-poloniex library. It suddenly stopped working with the TLSV1_ALERT_PROTOCOL_VERSION error.

Turns out that OpenSSL was fine, and trying to force a v1.2 connection was a huge wild goose chase - the library will use the latest version as necessary. The weak link in the chain was actually Python, which only defined ssl.PROTOCOL_TLSv1_2, and therefore started supporting TLS v1.2, since version 3.4.

Meanwhile, the version of Debian on the Beaglebone considers Python 3.3 the latest. The workaround I used was to install Python 3.5 from source (3.4 might have eventually worked too, but after hours of trial and error I'm done):

sudo apt-get install build-essential checkinstall
sudo apt-get install libreadline-gplv2-dev libncursesw5-dev libssl-dev libsqlite3-dev tk-dev libgdbm-dev libc6-dev libbz2-dev
wget https://www.python.org/ftp/python/3.5.4/Python-3.5.4.tgz
sudo tar xzf Python-3.5.4.tgz
cd Python-3.5.4
./configure
sudo make altinstall

Maybe not all those packages are strictly necessary, but installing them all at once saves a bunch of retries. The altinstall prevents the install from clobbering existing python binaries, installing as python3.5 instead, though that does mean you have to re-install additional libraries. The ./configure took a good five or ten minutes. The make took a couple of hours.

Now this still didn't work until I finally ran

sudo -H pip3.5 install requests[security]

Which also installs pyOpenSSL, cryptography and idna. I suspect pyOpenSSL was the key, so maybe pip3.5 install -U pyopenssl would have been sufficient but I've spent far too long on this already to make sure.

So in summary, if you get TLSV1_ALERT_PROTOCOL_VERSION error in Python, it's probably because you can't support TLS v1.2. To add support, you need at least the following:

  • OpenSSL 1.0.1
  • Python 3.4
  • requests[security]

This has got me past TLSV1_ALERT_PROTOCOL_VERSION, and now I get to battle with SSL23_GET_SERVER_HELLO instead.

Turns out this is back to the original issue of Python selecting the wrong SSL version. This can be confirmed by using this trick to mount a requests session with ssl_version=ssl.PROTOCOL_TLSv1_2. Without it, SSLv23 is used and the SSL23_GET_SERVER_HELLO error appears. With it, the request succeeds.

The final battle was to force TLSv1_2 to be picked when the request is made deep within a third party library. Both this method and this method ought to have done the trick, but neither made any difference. My final solution is horrible, but effective. I edited /usr/local/lib/python3.5/site-packages/urllib3/util/ssl_.py and changed

def resolve_ssl_version(candidate):
    """
    like resolve_cert_reqs
    """
    if candidate is None:
        return PROTOCOL_SSLv23

    if isinstance(candidate, str):
        res = getattr(ssl, candidate, None)
        if res is None:
            res = getattr(ssl, 'PROTOCOL_' + candidate)
        return res

    return candidate

to

def resolve_ssl_version(candidate):
    """
    like resolve_cert_reqs
    """
    if candidate is None:
        return ssl.PROTOCOL_TLSv1_2

    if isinstance(candidate, str):
        res = getattr(ssl, candidate, None)
        if res is None:
            res = getattr(ssl, 'PROTOCOL_' + candidate)
        return res

    return candidate

and voila, my script can finally contact the server again.

Angular update object in object array

Updating directly the item passed as argument should do the job, but I am maybe missing something here ?

updateItem(item){
  this.itemService.getUpdate(item.id)
  .subscribe(updatedItem => {
    item = updatedItem;
  });
}

EDIT : If you really have no choice but to loop through your entire array to update your item, use findIndex :

let itemIndex = this.items.findIndex(item => item.id == retrievedItem.id);
this.items[itemIndex] = retrievedItem;

Disable Button in Angular 2

Change ng-disabled="!contractTypeValid" to [disabled]="!contractTypeValid"

How to install/start Postman native v4.10.3 on Ubuntu 16.04 LTS 64-bit?

sudo snap install postman

This single command worked for me.

How to resolve Unneccessary Stubbing exception

In case of a large project, it's difficult to fix each of these exceptions. At the same time, using Silent is not advised. I have written a script to remove all the unnecessary stubbings given a list of them.

https://gist.github.com/cueo/da1ca49e92679ac49f808c7ef594e75b

We just need to copy-paste the mvn output and write the list of these exceptions using regex and let the script take care of the rest.

How to integrate SAP Crystal Reports in Visual Studio 2017

Visual Studio 2017 is supported in Crystal Reports SP 21, which is available for download as of 1 Sep 2017.

How can I regenerate ios folder in React Native project?

Since react-native eject is depreciated in 60.3 and I was getting diff errors trying to upgrade form 60.1 to 60.3 regenerating the android folder was not working.

I had to

rm -R node_modules

Then update react-native in package.json to 59.1 (remove package-lock.json)

Run

npm install

react-native eject

This will regenerate your android and ios folders Finally upgrade back to 60.3

react-native upgrade

react-native upgrade while back and 59.1 did not regenerate my android folder so the eject was necessary.

Cannot invoke an expression whose type lacks a call signature

Perhaps create a shared Fruit interface that provides isDecayed. fruits is now of type Fruit[] so the type can be explicit. Like this:

interface Fruit {
    isDecayed: boolean;
}

interface Apple extends Fruit {
    color: string;
}

interface Pear extends Fruit {
    weight: number;
}

interface FruitBasket {
    apples: Apple[];
    pears: Pear[];
}


const fruitBasket: FruitBasket = { apples: [], pears: [] };
const key: keyof FruitBasket = Math.random() > 0.5 ? 'apples': 'pears'; 
const fruits: Fruit[] = fruitBasket[key];

const freshFruits = fruits.filter((fruit) => !fruit.isDecayed);

Best way to import Observable from rxjs

Rxjs v 6.*

It got simplified with newer version of rxjs .

1) Operators

import {map} from 'rxjs/operators';

2) Others

import {Observable,of, from } from 'rxjs';

Instead of chaining we need to pipe . For example

Old syntax :

source.map().switchMap().subscribe()

New Syntax:

source.pipe(map(), switchMap()).subscribe()

Note: Some operators have a name change due to name collisions with JavaScript reserved words! These include:

do -> tap,

catch -> catchError

switch -> switchAll

finally -> finalize


Rxjs v 5.*

I am writing this answer partly to help myself as I keep checking docs everytime I need to import an operator . Let me know if something can be done better way.

1) import { Rx } from 'rxjs/Rx';

This imports the entire library. Then you don't need to worry about loading each operator . But you need to append Rx. I hope tree-shaking will optimize and pick only needed funcionts( need to verify ) As mentioned in comments , tree-shaking can not help. So this is not optimized way.

public cache = new Rx.BehaviorSubject('');

Or you can import individual operators .

This will Optimize your app to use only those files :

2) import { _______ } from 'rxjs/_________';

This syntax usually used for main Object like Rx itself or Observable etc.,

Keywords which can be imported with this syntax

 Observable, Observer, BehaviorSubject, Subject, ReplaySubject

3) import 'rxjs/add/observable/__________';

Update for Angular 5

With Angular 5, which uses rxjs 5.5.2+

import { empty } from 'rxjs/observable/empty';
import { concat} from 'rxjs/observable/concat';

These are usually accompanied with Observable directly. For example

Observable.from()
Observable.of()

Other such keywords which can be imported using this syntax:

concat, defer, empty, forkJoin, from, fromPromise, if, interval, merge, of, 
range, throw, timer, using, zip

4) import 'rxjs/add/operator/_________';

Update for Angular 5

With Angular 5, which uses rxjs 5.5.2+

import { filter } from 'rxjs/operators/filter';
import { map } from 'rxjs/operators/map';

These usually come in the stream after the Observable is created. Like flatMap in this code snippet:

Observable.of([1,2,3,4])
          .flatMap(arr => Observable.from(arr));

Other such keywords using this syntax:

audit, buffer, catch, combineAll, combineLatest, concat, count, debounce, delay, 
distinct, do, every, expand, filter, finally, find , first, groupBy,
ignoreElements, isEmpty, last, let, map, max, merge, mergeMap, min, pluck, 
publish, race, reduce, repeat, scan, skip, startWith, switch, switchMap, take, 
takeUntil, throttle, timeout, toArray, toPromise, withLatestFrom, zip

FlatMap: flatMap is alias to mergeMap so we need to import mergeMap to use flatMap.


Note for /add imports :

We only need to import once in whole project. So its advised to do it at a single place. If they are included in multiple files, and one of them is deleted, the build will fail for wrong reasons.

Asyncio.gather vs asyncio.wait

In addition to all the previous answers, I would like to tell about the different behavior of gather() and wait() in case they are cancelled.

Gather cancellation

If gather() is cancelled, all submitted awaitables (that have not completed yet) are also cancelled.

Wait cancellation

If the wait() task is cancelled, it simply throws an CancelledError and the waited tasks remain intact.

Simple example:

import asyncio


async def task(arg):
    await asyncio.sleep(5)
    return arg


async def cancel_waiting_task(work_task, waiting_task):
    await asyncio.sleep(2)
    waiting_task.cancel()
    try:
        await waiting_task
        print("Waiting done")
    except asyncio.CancelledError:
        print("Waiting task cancelled")

    try:
        res = await work_task
        print(f"Work result: {res}")
    except asyncio.CancelledError:
        print("Work task cancelled")


async def main():
    work_task = asyncio.create_task(task("done"))
    waiting = asyncio.create_task(asyncio.wait({work_task}))
    await cancel_waiting_task(work_task, waiting)

    work_task = asyncio.create_task(task("done"))
    waiting = asyncio.gather(work_task)
    await cancel_waiting_task(work_task, waiting)


asyncio.run(main())

Output:

asyncio.wait()
Waiting task cancelled
Work result: done
----------------
asyncio.gather()
Waiting task cancelled
Work task cancelled

Sometimes it becomes necessary to combine wait() and gather() functionality. For example, we want to wait for the completion of at least one task and cancel the rest pending tasks after that, and if the waiting itself was canceled, then also cancel all pending tasks.

As real examples, let's say we have a disconnect event and a work task. And we want to wait for the results of the work task, but if the connection was lost, then cancel it. Or we will make several parallel requests, but upon completion of at least one response, cancel all others.

It could be done this way:

import asyncio
from typing import Optional, Tuple, Set


async def wait_any(
        tasks: Set[asyncio.Future], *, timeout: Optional[int] = None,
) -> Tuple[Set[asyncio.Future], Set[asyncio.Future]]:
    tasks_to_cancel: Set[asyncio.Future] = set()
    try:
        done, tasks_to_cancel = await asyncio.wait(
            tasks, timeout=timeout, return_when=asyncio.FIRST_COMPLETED
        )
        return done, tasks_to_cancel
    except asyncio.CancelledError:
        tasks_to_cancel = tasks
        raise
    finally:
        for task in tasks_to_cancel:
            task.cancel()


async def task():
    await asyncio.sleep(5)


async def cancel_waiting_task(work_task, waiting_task):
    await asyncio.sleep(2)
    waiting_task.cancel()
    try:
        await waiting_task
        print("Waiting done")
    except asyncio.CancelledError:
        print("Waiting task cancelled")

    try:
        res = await work_task
        print(f"Work result: {res}")
    except asyncio.CancelledError:
        print("Work task cancelled")


async def check_tasks(waiting_task, working_task, waiting_conn_lost_task):
    try:
        await waiting_task
        print("waiting is done")
    except asyncio.CancelledError:
        print("waiting is cancelled")

    try:
        await waiting_conn_lost_task
        print("connection is lost")
    except asyncio.CancelledError:
        print("waiting connection lost is cancelled")

    try:
        await working_task
        print("work is done")
    except asyncio.CancelledError:
        print("work is cancelled")


async def work_done_case():
    working_task = asyncio.create_task(task())
    connection_lost_event = asyncio.Event()
    waiting_conn_lost_task = asyncio.create_task(connection_lost_event.wait())
    waiting_task = asyncio.create_task(wait_any({working_task, waiting_conn_lost_task}))
    await check_tasks(waiting_task, working_task, waiting_conn_lost_task)


async def conn_lost_case():
    working_task = asyncio.create_task(task())
    connection_lost_event = asyncio.Event()
    waiting_conn_lost_task = asyncio.create_task(connection_lost_event.wait())
    waiting_task = asyncio.create_task(wait_any({working_task, waiting_conn_lost_task}))
    await asyncio.sleep(2)
    connection_lost_event.set()  # <---
    await check_tasks(waiting_task, working_task, waiting_conn_lost_task)


async def cancel_waiting_case():
    working_task = asyncio.create_task(task())
    connection_lost_event = asyncio.Event()
    waiting_conn_lost_task = asyncio.create_task(connection_lost_event.wait())
    waiting_task = asyncio.create_task(wait_any({working_task, waiting_conn_lost_task}))
    await asyncio.sleep(2)
    waiting_task.cancel()  # <---
    await check_tasks(waiting_task, working_task, waiting_conn_lost_task)


async def main():
    print("Work done")
    print("-------------------")
    await work_done_case()
    print("\nConnection lost")
    print("-------------------")
    await conn_lost_case()
    print("\nCancel waiting")
    print("-------------------")
    await cancel_waiting_case()


asyncio.run(main())

Output:

Work done
-------------------
waiting is done
waiting connection lost is cancelled
work is done

Connection lost
-------------------
waiting is done
connection is lost
work is cancelled

Cancel waiting
-------------------
waiting is cancelled
waiting connection lost is cancelled
work is cancelled

ARG or ENV, which one to use in this case?

From Dockerfile reference:

  • The ARG instruction defines a variable that users can pass at build-time to the builder with the docker build command using the --build-arg <varname>=<value> flag.

  • The ENV instruction sets the environment variable <key> to the value <value>.
    The environment variables set using ENV will persist when a container is run from the resulting image.

So if you need build-time customization, ARG is your best choice.
If you need run-time customization (to run the same image with different settings), ENV is well-suited.

If I want to add let's say 20 (a random number) of extensions or any other feature that can be enable|disable

Given the number of combinations involved, using ENV to set those features at runtime is best here.

But you can combine both by:

  • building an image with a specific ARG
  • using that ARG as an ENV

That is, with a Dockerfile including:

ARG var
ENV var=${var}

You can then either build an image with a specific var value at build-time (docker build --build-arg var=xxx), or run a container with a specific runtime value (docker run -e var=yyy)

Removing object from array in Swift 3

The Swift equivalent to NSMutableArray's removeObject is:

var array = ["alpha", "beta", "gamma"]

if let index = array.firstIndex(of: "beta") {
    array.remove(at: index)
}

if the objects are unique. There is no need at all to cast to NSArray and use indexOfObject:

The API index(of: also works but this causes an unnecessary implicit bridge cast to NSArray.

If there are multiple occurrences of the same object use filter. However in cases like data source arrays where an index is associated with a particular object firstIndex(of is preferable because it's faster than filter.

Update:

In Swift 4.2+ you can remove one or multiple occurrences of beta with removeAll(where:):

array.removeAll{$0 == "beta"}

I get conflicting provisioning settings error when I try to archive to submit an iOS app

Try either of the following

1.Removing and adding ios platform and rebuild the project for ios

ionic cordova platform rm ios
ionic cordova platform add ios
ionic cordova build ios --release

2.Changing the Xcode Build Setting

The solution was to uncheck it, then check it again and reselect the Team. Xcode then fixed whatever was causing the issue on its own.

3.Change the following code in platform

This didn’t make any sense to me, since I had set the project to auto sign in xcode. Like you, the check and uncheck didn’t work. But then I read the last file path given and followed it. The file path is APP > Platforms > ios > Cordova > build-release.xconfig

And in the file, iPhone Distribution is explicitly set for CODE_SIGN_IDENTITY.

Change:

CODE_SIGN_IDENTITY = iPhone Distribution
CODE_SIGN_IDENTITY[sdk=iphoneos*] = iPhone Distribution

To:

CODE_SIGN_IDENTITY = iPhone Developer
CODE_SIGN_IDENTITY[sdk=iphoneos*] = iPhone Developer

Simple Android RecyclerView example

The following is a minimal example that will look like the following image.

RecyclerView with a list of animal names

Start with an empty activity. You will perform the following tasks to add the RecyclerView. All you need to do is copy and paste the code in each section. Later you can customize it to fit your needs.

  • Add dependencies to gradle
  • Add the xml layout files for the activity and for the RecyclerView row
  • Make the RecyclerView adapter
  • Initialize the RecyclerView in your activity

Update Gradle dependencies

Make sure the following dependencies are in your app gradle.build file:

implementation 'com.android.support:appcompat-v7:28.0.0'
implementation 'com.android.support:recyclerview-v7:28.0.0'

You can update the version numbers to whatever is the most current. Use compile rather than implementation if you are still using Android Studio 2.x.

Create activity layout

Add the RecyclerView to your xml layout.

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <android.support.v7.widget.RecyclerView
        android:id="@+id/rvAnimals"
        android:layout_width="match_parent"
        android:layout_height="match_parent"/>

</RelativeLayout>

Create row layout

Each row in our RecyclerView is only going to have a single TextView. Create a new layout resource file.

recyclerview_row.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="horizontal"
    android:padding="10dp">

    <TextView
        android:id="@+id/tvAnimalName"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="20sp"/>

</LinearLayout>

Create the adapter

The RecyclerView needs an adapter to populate the views in each row with your data. Create a new java file.

MyRecyclerViewAdapter.java

public class MyRecyclerViewAdapter extends RecyclerView.Adapter<MyRecyclerViewAdapter.ViewHolder> {

    private List<String> mData;
    private LayoutInflater mInflater;
    private ItemClickListener mClickListener;

    // data is passed into the constructor
    MyRecyclerViewAdapter(Context context, List<String> data) {
        this.mInflater = LayoutInflater.from(context);
        this.mData = data;
    }

    // inflates the row layout from xml when needed
    @Override
    public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View view = mInflater.inflate(R.layout.recyclerview_row, parent, false);
        return new ViewHolder(view);
    }

    // binds the data to the TextView in each row
    @Override
    public void onBindViewHolder(ViewHolder holder, int position) {
        String animal = mData.get(position);
        holder.myTextView.setText(animal);
    }

    // total number of rows
    @Override
    public int getItemCount() {
        return mData.size();
    }


    // stores and recycles views as they are scrolled off screen
    public class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
        TextView myTextView;

        ViewHolder(View itemView) {
            super(itemView);
            myTextView = itemView.findViewById(R.id.tvAnimalName);
            itemView.setOnClickListener(this);
        }

        @Override
        public void onClick(View view) {
            if (mClickListener != null) mClickListener.onItemClick(view, getAdapterPosition());
        }
    }

    // convenience method for getting data at click position
    String getItem(int id) {
        return mData.get(id);
    }

    // allows clicks events to be caught
    void setClickListener(ItemClickListener itemClickListener) {
        this.mClickListener = itemClickListener;
    }

    // parent activity will implement this method to respond to click events
    public interface ItemClickListener {
        void onItemClick(View view, int position);
    }
}

Notes

  • Although not strictly necessary, I included the functionality for listening for click events on the rows. This was available in the old ListViews and is a common need. You can remove this code if you don't need it.

Initialize RecyclerView in Activity

Add the following code to your main activity.

MainActivity.java

public class MainActivity extends AppCompatActivity implements MyRecyclerViewAdapter.ItemClickListener {

    MyRecyclerViewAdapter adapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        // data to populate the RecyclerView with
        ArrayList<String> animalNames = new ArrayList<>();
        animalNames.add("Horse");
        animalNames.add("Cow");
        animalNames.add("Camel");
        animalNames.add("Sheep");
        animalNames.add("Goat");

        // set up the RecyclerView
        RecyclerView recyclerView = findViewById(R.id.rvAnimals);
        recyclerView.setLayoutManager(new LinearLayoutManager(this));
        adapter = new MyRecyclerViewAdapter(this, animalNames);
        adapter.setClickListener(this);
        recyclerView.setAdapter(adapter);
    }

    @Override
    public void onItemClick(View view, int position) {
        Toast.makeText(this, "You clicked " + adapter.getItem(position) + " on row number " + position, Toast.LENGTH_SHORT).show();
    }
}

Notes

  • Notice that the activity implements the ItemClickListener that we defined in our adapter. This allows us to handle row click events in onItemClick.

Finished

That's it. You should be able to run your project now and get something similar to the image at the top.

Going on

Adding a divider between rows

You can add a simple divider like this

DividerItemDecoration dividerItemDecoration = new DividerItemDecoration(recyclerView.getContext(),
    layoutManager.getOrientation());
recyclerView.addItemDecoration(dividerItemDecoration);

If you want something a little more complex, see the following answers:

Changing row color on click

See this answer for how to change the background color and add the Ripple Effect when a row is clicked.

Insert single item

Updating rows

See this answer for how to add, remove, and update rows.

Insert single item

Further reading

Invalid http_host header

settings.py

ALLOWED_HOSTS = ['*']

docker cannot start on windows

In my case the WSL2 Linux-Kernel was missing, download, execute and restart:

https://docs.microsoft.com/de-de/windows/wsl/wsl2-kernel

Solved the problem.

Spring-boot default profile for integration tests

You could put an application.properties file in your test/resources folder. There you set

spring.profiles.active=test

This is kind of a default test profile while running tests.

Docker for Windows error: "Hardware assisted virtualization and data execution protection must be enabled in the BIOS"

If everything is fine with BIOS option I just forced disabling and enabling all HyperV features and this solved my issue --cmd Disable-WindowsOptionalFeature -Online -FeatureName Microsoft-Hyper-V-All --restart Enable-WindowsOptionalFeature -Online -FeatureName Microsoft-Hyper-V –All

Showing ValueError: shapes (1,3) and (1,3) not aligned: 3 (dim 1) != 1 (dim 0)

Unlike standard arithmetic, which desires matching dimensions, dot products require that the dimensions are one of:

  • (X..., A, B) dot (Y..., B, C) -> (X..., Y..., A, C), where ... means "0 or more different values
  • (B,) dot (B, C) -> (C,)
  • (A, B) dot (B,) -> (A,)
  • (B,) dot (B,) -> ()

Your problem is that you are using np.matrix, which is totally unnecessary in your code - the main purpose of np.matrix is to translate a * b into np.dot(a, b). As a general rule, np.matrix is probably not a good choice.

what is right way to do API call in react js?

In this case, you can do ajax call inside componentDidMount, and then update state

export default class UserList extends React.Component {
  constructor(props) {
    super(props);

    this.state = {person: []};
  }

  componentDidMount() {
    this.UserList();
  }

  UserList() {
    $.getJSON('https://randomuser.me/api/')
      .then(({ results }) => this.setState({ person: results }));
  }

  render() {
    const persons = this.state.person.map((item, i) => (
      <div>
        <h1>{ item.name.first }</h1>
        <span>{ item.cell }, { item.email }</span>
      </div>
    ));

    return (
      <div id="layout-content" className="layout-content-wrapper">
        <div className="panel-list">{ persons }</div>
      </div>
    );
  }
}

How to unpack an .asar file?

It is possible to upack without node installed using the following 7-Zip plugin:
http://www.tc4shell.com/en/7zip/asar/

Thanks @MayaPosch for mentioning that in this comment.

Normalizing images in OpenCV

If you want to change the range to [0, 1], make sure the output data type is float.

image = cv2.imread("lenacolor512.tiff", cv2.IMREAD_COLOR)  # uint8 image
norm_image = cv2.normalize(image, None, alpha=0, beta=1, norm_type=cv2.NORM_MINMAX, dtype=cv2.CV_32F)

How to check whether Kafka Server is running?

The good option is to use AdminClient as below before starting to produce or consume the messages

private static final int ADMIN_CLIENT_TIMEOUT_MS = 5000;           
 try (AdminClient client = AdminClient.create(properties)) {
            client.listTopics(new ListTopicsOptions().timeoutMs(ADMIN_CLIENT_TIMEOUT_MS)).listings().get();
        } catch (ExecutionException ex) {
            LOG.error("Kafka is not available, timed out after {} ms", ADMIN_CLIENT_TIMEOUT_MS);
            return;
        }

Swift 3 URLSession.shared() Ambiguous reference to member 'dataTask(with:completionHandler:) error (bug)

This problem is caused by URLSession has two dataTask methods

open func dataTask(with request: URLRequest, completionHandler: @escaping (Data?, URLResponse?, Error?) -> Swift.Void) -> URLSessionDataTask
open func dataTask(with url: URL, completionHandler: @escaping (Data?, URLResponse?, Error?) -> Swift.Void) -> URLSessionDataTask

The first one has URLRequest as parameter, and the second one has URL as parameter, so we need to specify which type to call, for example, I want to call the second method

let task = URLSession.shared.dataTask(with: url! as URL) {
    data, response, error in
    // Handler
}

how to get docker-compose to use the latest image from repository

If the docker compose configuration is in a file, simply run:

docker-compose -f appName.yml down && docker-compose -f appName.yml pull && docker-compose -f appName.yml up -d

"Uncaught (in promise) undefined" error when using with=location in Facebook Graph API query

The error tells you that there is an error but you don´t catch it. This is how you can catch it:

getAllPosts().then(response => {
    console.log(response);
}).catch(e => {
    console.log(e);
});

You can also just put a console.log(reponse) at the beginning of your API callback function, there is definitely an error message from the Graph API in it.

More information: https://developer.mozilla.org/de/docs/Web/JavaScript/Reference/Global_Objects/Promise/catch

Or with async/await:

//some async function
try {
    let response = await getAllPosts();
} catch(e) {
    console.log(e);
}

Python PIP Install throws TypeError: unsupported operand type(s) for -=: 'Retry' and 'int'

Updating setuptools has worked out fine for me.

sudo pip install --upgrade setuptools

Service located in another namespace

It is so simple to do it

if you want to use it as host and want to resolve it

If you are using ambassador to any other API gateway for service located in another namespace it's always suggested to use :

            Use : <service name>
            Use : <service.name>.<namespace name>
            Not : <service.name>.<namespace name>.svc.cluster.local

it will be like : servicename.namespacename.svc.cluster.local

this will send request to a particular service inside the namespace you have mention.

example:

kind: Service
apiVersion: v1
metadata:
  name: service
spec:
  type: ExternalName
  externalName: <servicename>.<namespace>.svc.cluster.local

Here replace the <servicename> and <namespace> with the appropriate value.

In Kubernetes, namespaces are used to create virtual environment but all are connect with each other.

MySQL: When is Flush Privileges in MySQL really needed?

Privileges assigned through GRANT option do not need FLUSH PRIVILEGES to take effect - MySQL server will notice these changes and reload the grant tables immediately.

From MySQL documentation:

If you modify the grant tables directly using statements such as INSERT, UPDATE, or DELETE, your changes have no effect on privilege checking until you either restart the server or tell it to reload the tables. If you change the grant tables directly but forget to reload them, your changes have no effect until you restart the server. This may leave you wondering why your changes seem to make no difference!

To tell the server to reload the grant tables, perform a flush-privileges operation. This can be done by issuing a FLUSH PRIVILEGES statement or by executing a mysqladmin flush-privileges or mysqladmin reload command.

If you modify the grant tables indirectly using account-management statements such as GRANT, REVOKE, SET PASSWORD, or RENAME USER, the server notices these changes and loads the grant tables into memory again immediately.

How do I add a custom script to my package.json file that runs a javascript file?

Custom Scripts

npm run-script <custom_script_name>

or

npm run <custom_script_name>

In your example, you would want to run npm run-script script1 or npm run script1.

See https://docs.npmjs.com/cli/run-script

Lifecycle Scripts

Node also allows you to run custom scripts for certain lifecycle events, like after npm install is run. These can be found here.

For example:

"scripts": {
    "postinstall": "electron-rebuild",
},

This would run electron-rebuild after a npm install command.

How to fix Error: this class is not key value coding-compliant for the key tableView.'

You have your storyboard set up to expect an outlet called tableView but the actual outlet name is myTableView.

If you delete the connection in the storyboard and reconnect to the right variable name, it should fix the problem.

Why Is `Export Default Const` invalid?

Paul's answer is the one you're looking for. However, as a practical matter, I think you may be interested in the pattern I've been using in my own React+Redux apps.

Here's a stripped-down example from one of my routes, showing how you can define your component and export it as default with a single statement:

import React from 'react';
import { connect } from 'react-redux';

@connect((state, props) => ({
    appVersion: state.appVersion
    // other scene props, calculated from app state & route props
}))
export default class SceneName extends React.Component { /* ... */ }

(Note: I use the term "Scene" for the top-level component of any route).

I hope this is helpful. I think it's much cleaner-looking than the conventional connect( mapState, mapDispatch )( BareComponent )

Fine control over the font size in Seaborn plots for academic papers

It is all but satisfying, isn't it? The easiest way I have found to specify when setting the context, e.g.:

sns.set_context("paper", rc={"font.size":8,"axes.titlesize":8,"axes.labelsize":5})   

This should take care of 90% of standard plotting usage. If you want ticklabels smaller than axes labels, set the 'axes.labelsize' to the smaller (ticklabel) value and specify axis labels (or other custom elements) manually, e.g.:

axs.set_ylabel('mylabel',size=6)

you could define it as a function and load it in your scripts so you don't have to remember your standard numbers, or call it every time.

def set_pubfig:
    sns.set_context("paper", rc={"font.size":8,"axes.titlesize":8,"axes.labelsize":5})   

Of course you can use configuration files, but I guess the whole idea is to have a simple, straightforward method, which is why the above works well.

Note: If you specify these numbers, specifying font_scale in sns.set_context is ignored for all specified font elements, even if you set it.

TypeScript for ... of with index / key?

You can use the for..in TypeScript operator to access the index when dealing with collections.

var test = [7,8,9];
for (var i in test) {
   console.log(i + ': ' + test[i]);
} 

Output:

 0: 7
 1: 8
 2: 9

See Demo

Could not find server 'server name' in sys.servers. SQL Server 2014

I figured out the issue. The linked server was created correctly. However, after the server was upgraded and switched the server name in sys.servers still had the old server name.

I had to drop the old server name and add the new server name to sys.servers on the new server

sp_dropserver 'Server_A'
GO
sp_addserver  'Server',local
GO

ITSAppUsesNonExemptEncryption export compliance while internal testing?

The same error solved like this

enter image description here

    using UnityEngine;
    using System.Collections;
    using UnityEditor.Callbacks;
    using UnityEditor;
    using System;
    using UnityEditor.iOS.Xcode;
    using System.IO;

public class AutoIncrement : MonoBehaviour {

    [PostProcessBuild]
    public static void ChangeXcodePlist(BuildTarget buildTarget, string pathToBuiltProject)
    {

        if (buildTarget == BuildTarget.iOS)
        {

            // Get plist
            string plistPath = pathToBuiltProject + "/Info.plist";
            var plist = new PlistDocument();
            plist.ReadFromString(File.ReadAllText(plistPath));

            // Get root
            var rootDict = plist.root;

            // Change value of NSCameraUsageDescription in Xcode plist
            var buildKey = "NSCameraUsageDescription";
            rootDict.SetString(buildKey, "Taking screenshots");

            var buildKey2 = "ITSAppUsesNonExemptEncryption";
            rootDict.SetString(buildKey2, "false");


            // Write to file
            File.WriteAllText(plistPath, plist.WriteToString());
        }
    }
    // Use this for initialization
    void Start () {

    }

    // Update is called once per frame
    void Update () {

    }

    [PostProcessBuild]
    public static void OnPostprocessBuild(BuildTarget target, string pathToBuiltProject)
    {
        //A new build has happened so lets increase our version number
        BumpBundleVersion();
    }


    // Bump version number in PlayerSettings.bundleVersion
    private static void BumpBundleVersion()
    {
        float versionFloat;

        if (float.TryParse(PlayerSettings.bundleVersion, out versionFloat))
        {
            versionFloat += 0.01f;
            PlayerSettings.bundleVersion = versionFloat.ToString();
        }
    }
    [MenuItem("Leman/Build iOS Development", false, 10)]
    public static void CustomBuild()
    {
        BumpBundleVersion();
        var levels= new String[] { "Assets\\ShootTheBall\\Scenes\\MainScene.unity" };
        BuildPipeline.BuildPlayer(levels, 
            "iOS", BuildTarget.iOS, BuildOptions.Development);
    }

}

TypeError: ufunc 'add' did not contain a loop with signature matching types

You have a numpy array of strings, not floats. This is what is meant by dtype('<U9') -- a little endian encoded unicode string with up to 9 characters.

try:

return sum(np.asarray(listOfEmb, dtype=float)) / float(len(listOfEmb))

However, you don't need numpy here at all. You can really just do:

return sum(float(embedding) for embedding in listOfEmb) / len(listOfEmb)

Or if you're really set on using numpy.

return np.asarray(listOfEmb, dtype=float).mean()

How to make canvas responsive

The object-fit CSS property sets how the content of a replaced element, such as an img or video, should be resized to fit its container.

Magically, object fit also works on a canvas element. No JavaScript needed, and the canvas doesn't stretch, automatically fills to proportion.

canvas {
    width: 100%;
    object-fit: contain;
}

Error reading JObject from JsonReader. Current JsonReader item is not an object: StartArray. Path

I ran into a very similar problem with my Xamarin Windows Phone 8.1 app. The reason JObject.Parse(json) would not work for me was because my Json had a beginning "[" and an ending "]". In order to make it work, I had to remove those two characters. From your example, it looks like you might have the same issue.

jsonResult = jsonResult.TrimStart(new char[] { '[' }).TrimEnd(new char[] { ']' });

I was then able to use the JObject.Parse(jsonResult) and everything worked.

Importing lodash into angular2 + typescript application

I had created typings for lodash-es also, so now you can actually do the following

install

npm install lodash-es -S
npm install @types/lodash-es -D

usage

import kebabCase from "lodash-es/kebabCase";
const wings = kebabCase("chickenWings");

if you use rollup, i suggest using this instead of the lodash as it will be treeshaken properly.

converting json to string in python

json.dumps() is much more than just making a string out of a Python object, it would always produce a valid JSON string (assuming everything inside the object is serializable) following the Type Conversion Table.

For instance, if one of the values is None, the str() would produce an invalid JSON which cannot be loaded:

>>> data = {'jsonKey': None}
>>> str(data)
"{'jsonKey': None}"
>>> json.loads(str(data))
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/json/__init__.py", line 338, in loads
    return _default_decoder.decode(s)
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/json/decoder.py", line 366, in decode
    obj, end = self.raw_decode(s, idx=_w(s, 0).end())
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/json/decoder.py", line 382, in raw_decode
    obj, end = self.scan_once(s, idx)
ValueError: Expecting property name: line 1 column 2 (char 1)

But the dumps() would convert None into null making a valid JSON string that can be loaded:

>>> import json
>>> data = {'jsonKey': None}
>>> json.dumps(data)
'{"jsonKey": null}'
>>> json.loads(json.dumps(data))
{u'jsonKey': None}

How do I add an active class to a Link from React Router?

Its very easy to do that, react-router-dom provides all.

_x000D_
_x000D_
import React from 'react';_x000D_
import { matchPath, withRouter } from 'react-router';_x000D_
    _x000D_
class NavBar extends React.Component {_x000D_
  render(){_x000D_
    return(_x000D_
       <ul className="sidebar-menu">_x000D_
      <li className="header">MAIN NAVIGATION</li>_x000D_
      <li className={matchPath(this.props.location.pathname, { path: "/dashboard" }) ? 'active' : ''}><Link to="dashboard"><i className="fa fa-dashboard"></i> _x000D_
        <span>Dashboard</span></Link></li>_x000D_
      <li className={matchPath(this.props.location.pathname, { path: "/email_lists" }) ? 'active' : ''}><Link to="email_lists"><i className="fa fa-envelope-o"></i> _x000D_
        <span>Email Lists</span></Link></li>_x000D_
      <li className={matchPath(this.props.location.pathname, { path: "/billing" }) ? 'active' : ''}><Link to="billing"><i className="fa fa-credit-card"></i> _x000D_
        <span>Buy Verifications</span></Link></li>_x000D_
    </ul>_x000D_
      )_x000D_
   }_x000D_
}_x000D_
    _x000D_
export default withRouter(NavBar);
_x000D_
_x000D_
_x000D_

Wrapping You Navigation Component with withRouter() HOC will provide few props to your component: 1. match 2. history 3. location

here i used matchPath() method from react-router to compare the paths and decide if the 'li' tag should get "active" class name or not. and Im accessing the location from this.props.location.pathname.

changing the path name in props will happen when our link is clicked, and location props will get updated NavBar also get re-rendered and active style will get applied

Cannot install signed apk to device manually, got error "App not installed"

File > Project Structure > Build Variants > Select release > Make sure 'Signing Config' is not empty > if it is select from the drop window the $signingConfigs.release

I did this with Android Studio 3.1.4 and it allowed me to create a release apk after following all the steps above of creating the release apk and release key and adding the info to the app gradle. Cheers!

Setting up and using Meld as your git difftool and mergetool

I follow this simple setup with meld. Meld is free and opensource diff tool. You will see nice side by side comparison of files and directory for any code changes.

  1. Install meld in your Linux using yum/apt.
  2. Add following line in your ~/.gitconfig file
[diff]
    tool = meld
  1. Go to your code repo and type following command to see difference between last committed changes and current working directory (Unstaged uncommited changes)

git difftool --dir-diff ./

  1. To see difference between last committed code and staged code, use following command

git difftool --cached --dir-diff ./

"unexpected token import" in Nodejs5 and babel?

babel-preset-es2015 is now deprecated and you'll get a warning if you try to use Laurence's solution.

To get this working with Babel 6.24.1+, use babel-preset-env instead:

npm install babel-preset-env --save-dev

Then add env to your presets in your .babelrc:

{
  "presets": ["env"]
}

See the Babel docs for more info.

How do I completely rename an Xcode project (i.e. inclusive of folders)?

Extra instructions when following @Luke-West's + @Vaiden's solutions:

  • If your scheme has not changed (still showing my mac) on the top left next to the stop button:
  1. Click NEWLY created Project name (next to stop button) > Click Edit Schemes > Build (left hand side) > Remove the old target (will say it's missing) and replace with the NEWLY named project under NEWLY named project logo

Also, I did not have to use step 3 of @Vaiden's solution. Just running rm -rf Pods/ in terminal got rid of all old pod files

I also did not have to use step 9 in @Vaiden's solution, instead I just removed the OLD project named framework under Link Binary Libraries (the NEWLY named framework was already there)

So the updated steps would be as follows:

Step 1 - Rename the project

  1. If you are using cocoapods in your project, close the workspace, and open the XCode project for these steps.
  2. Click on the project you want to rename in the "Project navigator" on the left of the Xcode view.
  3. On the right select the "File inspector" and the name of your project should be in there under "Identity and Type", change it to the new name.
  4. Click "Rename" in a dropdown menu

Step 2 - Rename the Scheme

  1. In the top bar (near "Stop" button), there is a scheme for your OLD product, click on it, then go to "Manage schemes"
  2. Click on the OLD name in the scheme, and it will become editable, change the name
  3. Quit XCode.
  4. In the master folder, rename OLD.xcworkspace to NEW.xcworkspace.

Step 3 - Rename the folder with your assets

  1. Quit Xcode
  2. In the correctly named master folder, there is a newly named xcodeproj file with the the wrongly named OLD folder. Rename the OLD folder to your new name
  3. Reopen the project, you will see a warning: "The folder OLD does not exist", dismiss the warning
  4. In the "Project navigator" on the left, click the top level OLD folder name
  5. In Utilities pane under "Identity and type" you will see the "Name" entry, change this from the OLD to the new name
  6. Just below there is a "Location" entry. Click on a folder with the OLD name and chose the newly renamed folder

Step 4 - Rename the Build plist data

  1. Click on the project in the "Project navigator" on the left, in the main panel select "Build Settings"
  2. Search for "plist" in this section Under packaging, you will see Info.plist, and Product bundle identifier
  3. Rename the top entry in Info.plist
  4. Do the same for Product Identifier

Step 5 Handling Podfile

  1. In XCode: choose and edit Podfile from the project navigator. You should see a target clause with the OLD name. Change it to NEW.
  2. Quit XCode.
  3. In terminal, cd into project directory, then: pod deintegrate
  4. Run pod install.
  5. Open XCode.
  6. Click on your project name in the project navigator.
  7. In the main pane, switch to the Build Phases tab. Under Link Binary With Libraries, look for the OLD framework and remove it (should say it is missing) The NEWLY named framework should already be there, if not use the "+" button at the bottom of the window to add it
  8. If you have an objective-c Bridging header go to Build settings and change the location of the header from OLD/OLD-Bridging-Header.h to NEW/NEW-Bridging-Header.h
  9. Clean and run.

You should be able to build with no errors after you have followed all of the steps successfully

Convert time.Time to string

package main                                                                                                                                                           

import (
    "fmt"
    "time"
)

// @link https://golang.org/pkg/time/

func main() {

    //caution : format string is `2006-01-02 15:04:05.000000000`
    current := time.Now()

    fmt.Println("origin : ", current.String())
    // origin :  2016-09-02 15:53:07.159994437 +0800 CST

    fmt.Println("mm-dd-yyyy : ", current.Format("01-02-2006"))
    // mm-dd-yyyy :  09-02-2016

    fmt.Println("yyyy-mm-dd : ", current.Format("2006-01-02"))
    // yyyy-mm-dd :  2016-09-02

    // separated by .
    fmt.Println("yyyy.mm.dd : ", current.Format("2006.01.02"))
    // yyyy.mm.dd :  2016.09.02

    fmt.Println("yyyy-mm-dd HH:mm:ss : ", current.Format("2006-01-02 15:04:05"))
    // yyyy-mm-dd HH:mm:ss :  2016-09-02 15:53:07

    // StampMicro
    fmt.Println("yyyy-mm-dd HH:mm:ss: ", current.Format("2006-01-02 15:04:05.000000"))
    // yyyy-mm-dd HH:mm:ss:  2016-09-02 15:53:07.159994

    //StampNano
    fmt.Println("yyyy-mm-dd HH:mm:ss: ", current.Format("2006-01-02 15:04:05.000000000"))
    // yyyy-mm-dd HH:mm:ss:  2016-09-02 15:53:07.159994437
}    

How to add LocalDB to Visual Studio 2015 Community's SQL Server Object Explorer?

I tried to install only LocalDB, which was missed in my VS 2015 installation. Followed below URL & selectively download the LocalDB (2012) installer which is only 33mb in size :)

https://www.microsoft.com/en-us/download/details.aspx?id=29062

If you are looking for the SQL Server Data Tool for Visual Studio 2015 Integration, then Please download that from :

https://msdn.microsoft.com/en-us/mt186501

The resource could not be loaded because the App Transport Security policy requires the use of a secure connection

I have solved as plist file.

Add a NSAppTransportSecurity : Dictionary.

Add Subkey named " NSAllowsArbitraryLoads " as Boolean : YES

enter image description here

How to update/refresh specific item in RecyclerView

A way that has worked for me personally, is using the recyclerview's adapter methods to deal with changes in it's items.

It would go in a way similar to this, create a method in your custom recycler's view somewhat like this:

public void modifyItem(final int position, final Model model) {
    mainModel.set(position, model);
    notifyItemChanged(position);
}

How to delete multiple pandas (python) dataframes from memory to save RAM?

This will delete the dataframe and will release the RAM/memory

del [[df_1,df_2]]
gc.collect()
df_1=pd.DataFrame()
df_2=pd.DataFrame()

the data-frame will be explicitly set to null

in the above statements

Firstly, the self reference of the dataframe is deleted meaning the dataframe is no longer available to python there after all the references of the dataframe is collected by garbage collector (gc.collect()) and then explicitly set all the references to empty dataframe.

more on the working of garbage collector is well explained in https://stackify.com/python-garbage-collection/

Change the location of the ~ directory in a Windows install of Git Bash

In my case, all I had to do was add the following User variable on Windows:

Variable name: HOME
Variable value: %USERPROFILE%

How to set a Environment Variable (You can use the User variables for username section if you are not a system administrator)

Rendering React Components from Array of Objects

I have an answer that might be a bit less confusing for newbies like myself. You can just use map within the components render method.

render () {
   return (
       <div>
           {stations.map(station => <div key={station}> {station} </div>)} 
       </div>
   );
}

Adding ASP.NET MVC5 Identity Authentication to an existing project

Configuring Identity to your existing project is not hard thing. You must install some NuGet package and do some small configuration.

First install these NuGet packages with Package Manager Console:

PM> Install-Package Microsoft.AspNet.Identity.Owin 
PM> Install-Package Microsoft.AspNet.Identity.EntityFramework
PM> Install-Package Microsoft.Owin.Host.SystemWeb 

Add a user class and with IdentityUser inheritance:

public class AppUser : IdentityUser
{
    //add your custom properties which have not included in IdentityUser before
    public string MyExtraProperty { get; set; }  
}

Do same thing for role:

public class AppRole : IdentityRole
{
    public AppRole() : base() { }
    public AppRole(string name) : base(name) { }
    // extra properties here 
}

Change your DbContext parent from DbContext to IdentityDbContext<AppUser> like this:

public class MyDbContext : IdentityDbContext<AppUser>
{
    // Other part of codes still same 
    // You don't need to add AppUser and AppRole 
    // since automatically added by inheriting form IdentityDbContext<AppUser>
}

If you use the same connection string and enabled migration, EF will create necessary tables for you.

Optionally, you could extend UserManager to add your desired configuration and customization:

public class AppUserManager : UserManager<AppUser>
{
    public AppUserManager(IUserStore<AppUser> store)
        : base(store)
    {
    }

    // this method is called by Owin therefore this is the best place to configure your User Manager
    public static AppUserManager Create(
        IdentityFactoryOptions<AppUserManager> options, IOwinContext context)
    {
        var manager = new AppUserManager(
            new UserStore<AppUser>(context.Get<MyDbContext>()));

        // optionally configure your manager
        // ...

        return manager;
    }
}

Since Identity is based on OWIN you need to configure OWIN too:

Add a class to App_Start folder (or anywhere else if you want). This class is used by OWIN. This will be your startup class.

namespace MyAppNamespace
{
    public class IdentityConfig
    {
        public void Configuration(IAppBuilder app)
        {
            app.CreatePerOwinContext(() => new MyDbContext());
            app.CreatePerOwinContext<AppUserManager>(AppUserManager.Create);
            app.CreatePerOwinContext<RoleManager<AppRole>>((options, context) =>
                new RoleManager<AppRole>(
                    new RoleStore<AppRole>(context.Get<MyDbContext>())));

            app.UseCookieAuthentication(new CookieAuthenticationOptions
            {
                AuthenticationType = DefaultAuthenticationTypes.ApplicationCookie,
                LoginPath = new PathString("/Home/Login"),
            });
        }
    }
}

Almost done just add this line of code to your web.config file so OWIN could find your startup class.

<appSettings>
    <!-- other setting here -->
    <add key="owin:AppStartup" value="MyAppNamespace.IdentityConfig" />
</appSettings>

Now in entire project you could use Identity just like any new project had already installed by VS. Consider login action for example

[HttpPost]
public ActionResult Login(LoginViewModel login)
{
    if (ModelState.IsValid)
    {
        var userManager = HttpContext.GetOwinContext().GetUserManager<AppUserManager>();
        var authManager = HttpContext.GetOwinContext().Authentication;

        AppUser user = userManager.Find(login.UserName, login.Password);
        if (user != null)
        {
            var ident = userManager.CreateIdentity(user, 
                DefaultAuthenticationTypes.ApplicationCookie);
            //use the instance that has been created. 
            authManager.SignIn(
                new AuthenticationProperties { IsPersistent = false }, ident);
            return Redirect(login.ReturnUrl ?? Url.Action("Index", "Home"));
        }
    }
    ModelState.AddModelError("", "Invalid username or password");
    return View(login);
}

You could make roles and add to your users:

public ActionResult CreateRole(string roleName)
{
    var roleManager=HttpContext.GetOwinContext().GetUserManager<RoleManager<AppRole>>();

    if (!roleManager.RoleExists(roleName))
        roleManager.Create(new AppRole(roleName));
    // rest of code
} 

You could also add a role to a user, like this:

UserManager.AddToRole(UserManager.FindByName("username").Id, "roleName");

By using Authorize you could guard your actions or controllers:

[Authorize]
public ActionResult MySecretAction() {}

or

[Authorize(Roles = "Admin")]]
public ActionResult MySecretAction() {}

You can also install additional packages and configure them to meet your requirement like Microsoft.Owin.Security.Facebook or whichever you want.

Note: Don't forget to add relevant namespaces to your files:

using Microsoft.AspNet.Identity;
using Microsoft.Owin.Security;
using Microsoft.AspNet.Identity.Owin;
using Microsoft.AspNet.Identity.EntityFramework;
using Microsoft.Owin;
using Microsoft.Owin.Security.Cookies;
using Owin;

You could also see my other answers like this and this for advanced use of Identity.

How to create full path with node's fs.mkdirSync?

This version works better on Windows than the top answer because it understands both / and path.sep so that forward slashes work on Windows as they should. Supports absolute and relative paths (relative to the process.cwd).

/**
 * Creates a folder and if necessary, parent folders also. Returns true
 * if any folders were created. Understands both '/' and path.sep as 
 * path separators. Doesn't try to create folders that already exist,
 * which could cause a permissions error. Gracefully handles the race 
 * condition if two processes are creating a folder. Throws on error.
 * @param targetDir Name of folder to create
 */
export function mkdirSyncRecursive(targetDir) {
  if (!fs.existsSync(targetDir)) {
    for (var i = targetDir.length-2; i >= 0; i--) {
      if (targetDir.charAt(i) == '/' || targetDir.charAt(i) == path.sep) {
        mkdirSyncRecursive(targetDir.slice(0, i));
        break;
      }
    }
    try {
      fs.mkdirSync(targetDir);
      return true;
    } catch (err) {
      if (err.code !== 'EEXIST') throw err;
    }
  }
  return false;
}

Getting a 500 Internal Server Error on Laravel 5+ Ubuntu 14.04

I fixed with this Command:

   rm -rf app/storage/logs/laravel.logs
   chmod -R 777 app/storage,
   php artisan cache:clear,
   php artisan dump-autoload OR composer dump-autoload

Than restart a server eather XAMPP ore another one and that should be working.

Node JS Promise.all and forEach

I had through the same situation. I solved using two Promise.All().

I think was really good solution, so I published it on npm: https://www.npmjs.com/package/promise-foreach

I think your code will be something like this

var promiseForeach = require('promise-foreach')
var jsonItems = [];
promiseForeach.each(jsonItems,
    [function (jsonItems){
        return new Promise(function(resolve, reject){
            if(jsonItems.type === 'file'){
                jsonItems.getFile().then(function(file){ //or promise.all?
                    resolve(file.getSize())
                })
            }
        })
    }],
    function (result, current) {
        return {
            type: current.type,
            size: jsonItems.result[0]
        }
    },
    function (err, newList) {
        if (err) {
            console.error(err)
            return;
        }
        console.log('new jsonItems : ', newList)
    })

TypeError: $(...).DataTable is not a function

CAUSE

There could be multiple reasons for this error.

  • jQuery DataTables library is missing.
  • jQuery library is loaded after jQuery DataTables.
  • Multiple versions of jQuery library is loaded.

SOLUTION

Include only one version of jQuery library version 1.7 or newer before jQuery DataTables.

For example:

<script src="js/jquery.min.js" type="text/javascript"></script>
<script src="js/jquery.dataTables.min.js" type="text/javascript"></script>

See jQuery DataTables: Common JavaScript console errors for more information on this and other common console errors.

"Initializing" variables in python?

def grade(inlist):
    grade_1, grade_2, grade_3, average =inlist
    print (grade_1)
    print (grade_2)

mark=[1,2,3,4]
grade(mark)

How do I trim() a string in angularjs?

Why don't you simply use JavaScript's trim():

str.trim() //Will work everywhere irrespective of any framework.

For compatibility with <IE9 use:

if(typeof String.prototype.trim !== 'function') {
  String.prototype.trim = function() {
    return this.replace(/^\s+|\s+$/g, ''); 
  }
}

Found it Here

Spring Data JPA and Exists query

You can use Case expression for returning a boolean in your select query like below.

@Query("SELECT CASE WHEN count(e) > 0 THEN true ELSE false END FROM MyEntity e where e.my_column = ?1")

How to bundle vendor scripts separately and require them as needed with Webpack?

I am not sure if I fully understand your problem but since I had similar issue recently I will try to help you out.

Vendor bundle.

You should use CommonsChunkPlugin for that. in the configuration you specify the name of the chunk (e.g. vendor), and file name that will be generated (vendor.js).

new webpack.optimize.CommonsChunkPlugin("vendor", "vendor.js", Infinity),

Now important part, you have to now specify what does it mean vendor library and you do that in an entry section. One one more item to entry list with the same name as the name of the newly declared chunk (i.e. 'vendor' in this case). The value of that entry should be the list of all the modules that you want to move to vendor bundle. in your case it should look something like:

entry: {
    app: 'entry.js',
    vendor: ['jquery', 'jquery.plugin1']
}

JQuery as global

Had the same problem and solved it with ProvidePlugin. here you are not defining global object but kind of shurtcuts to modules. i.e. you can configure it like that:

new webpack.ProvidePlugin({
    $: "jquery"
})

And now you can just use $ anywhere in your code - webpack will automatically convert that to

require('jquery')

I hope it helped. you can also look at my webpack configuration file that is here

I love webpack, but I agree that the documentation is not the nicest one in the world... but hey.. people were saying same thing about Angular documentation in the begining :)


Edit:

To have entrypoint-specific vendor chunks just use CommonsChunkPlugins multiple times:

new webpack.optimize.CommonsChunkPlugin("vendor-page1", "vendor-page1.js", Infinity),
new webpack.optimize.CommonsChunkPlugin("vendor-page2", "vendor-page2.js", Infinity),

and then declare different extenral libraries for different files:

entry: {
    page1: ['entry.js'],
    page2: ['entry2.js'],
    "vendor-page1": [
        'lodash'
    ],
    "vendor-page2": [
        'jquery'
    ]
},

If some libraries are overlapping (and for most of them) between entry points then you can extract them to common file using same plugin just with different configuration. See this example.

Convert list or numpy array of single element to float in python

np.asscalar(a) is deprecated since NumPy v1.16, use a.item() instead.

For example:

a = np.array([[0.6813]])
print(a.item())

gives:

0.6813

How to install VS2015 Community Edition offline

I think the ISO version is smaller than the Layout method because the ISO version is just in English or whatever language it is that you choose, however the "Layout" version is ALL of the languages available, So for example if the "Layout" version downloads a 3gb file(English Version) it will download the same 3gb file in another language that you will not ever use wasting your downloads, time and all that other good stuff.

How to resolve TypeError: Cannot convert undefined or null to object

Replace

if (typeof obj === 'undefined') { return undefined;} // return undefined for undefined
if (obj === 'null') { return null;} // null unchanged

with

if (obj === undefined) { return undefined;} // return undefined for undefined 
if (obj === null) { return null;} // null unchanged

Convert Dictionary to JSON in Swift

private func convertDictToJson(dict : NSDictionary) -> NSDictionary?
{
    var jsonDict : NSDictionary!

    do {
        let jsonData = try JSONSerialization.data(withJSONObject:dict, options:[])
        let jsonDataString = String(data: jsonData, encoding: String.Encoding.utf8)!
        print("Post Request Params : \(jsonDataString)")
        jsonDict = [ParameterKey : jsonDataString]
        return jsonDict
    } catch {
        print("JSON serialization failed:  \(error)")
        jsonDict = nil
    }
    return jsonDict
}

Bootstrap's JavaScript requires jQuery version 1.9.1 or higher

There is problem with Bootstrap version and jQuery version in my case.. I fixeed it by changing the version of Bootstrap and jQuery. thank you!!

ECMAScript 6 arrow function that returns an object

Issue:

When you do are doing:

p => {foo: "bar"}

JavaScript interpreter thinks you are opening a multi-statement code block, and in that block, you have to explicitly mention a return statement.

Solution:

If your arrow function expression has a single statement, then you can use the following syntax:

p => ({foo: "bar", attr2: "some value", "attr3": "syntax choices"})

But if you want to have multiple statements then you can use the following syntax:

p => {return {foo: "bar", attr2: "some value", "attr3": "syntax choices"}}

In above example, first set of curly braces opens a multi-statement code block, and the second set of curly braces is for dynamic objects. In multi-statement code block of arrow function, you have to explicitly use return statements

For more details, check Mozilla Docs for JS Arrow Function Expressions

Call static methods from regular ES6 class methods

Both ways are viable, but they do different things when it comes to inheritance with an overridden static method. Choose the one whose behavior you expect:

class Super {
  static whoami() {
    return "Super";
  }
  lognameA() {
    console.log(Super.whoami());
  }
  lognameB() {
    console.log(this.constructor.whoami());
  }
}
class Sub extends Super {
  static whoami() {
    return "Sub";
  }
}
new Sub().lognameA(); // Super
new Sub().lognameB(); // Sub

Referring to the static property via the class will be actually static and constantly give the same value. Using this.constructor instead will use dynamic dispatch and refer to the class of the current instance, where the static property might have the inherited value but could also be overridden.

This matches the behavior of Python, where you can choose to refer to static properties either via the class name or the instance self.

If you expect static properties not to be overridden (and always refer to the one of the current class), like in Java, use the explicit reference.

"Could not find acceptable representation" using spring-boot-starter-web

accepted answer is not right with Spring 5. try changing your URL of your web service to .json! that is the right fix. great details here http://stick2code.blogspot.com/2014/03/solved-orgspringframeworkwebhttpmediaty.html

Synchronous XMLHttpRequest warning and <script>

In my case this was caused by the flexie script which was part of the "CDNJS Selections" app offered by Cloudflare.

According to Cloudflare "This app is being deprecated in March 2015". I turned it off and the message disappeared instantly.

You can access the apps by visiting https://www.cloudflare.com/a/cloudflare-apps/yourdomain.com

UICollectionView - dynamic cell height?

Follow bolnad answer up to Step 4.

Then make it simpler by replacing all the other steps with:

func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {

    // Configure your cell
    sizingNibNew.configureCell(data as! CustomCellData, delegate: self)

    // We use the full width minus insets
    let width = collectionView.frame.size.width - collectionView.sectionInset.left - collectionView.sectionInset.right

    // Constrain our cell to this width 
    let height = sizingNibNew.systemLayoutSizeFitting(CGSize(width: width, height: .infinity), withHorizontalFittingPriority: UILayoutPriorityRequired, verticalFittingPriority: UILayoutPriorityFittingSizeLevel).height

    return CGSize(width: width, height: height)
}

- java.lang.NullPointerException - setText on null object reference

Here lies your problem:

private void fillTextView (int id, String text) {
    TextView tv = (TextView) findViewById(id);
    tv.setText(text); // tv is null
}

--> (TextView) findViewById(id); // returns null But from your code, I can't find why this method returns null. Try to track down, what id you give as a parameter and if this view with the specified id exists.

The error message is very clear and even tells you at what method. From the documentation:

public final View findViewById (int id)
    Look for a child view with the given id. If this view has the given id, return this view.
    Parameters
        id  The id to search for.
    Returns
        The view that has the given id in the hierarchy or null

http://developer.android.com/reference/android/view/View.html#findViewById%28int%29

In other words: You have no view with the id you give as a parameter.

How do I wait for a promise to finish before returning the variable of a function?

Instead of returning a resultsArray you return a promise for a results array and then then that on the call site - this has the added benefit of the caller knowing the function is performing asynchronous I/O. Coding concurrency in JavaScript is based on that - you might want to read this question to get a broader idea:

function resultsByName(name)
{   
    var Card = Parse.Object.extend("Card");
    var query = new Parse.Query(Card);
    query.equalTo("name", name.toString());

    var resultsArray = [];

    return query.find({});                           

}

// later
resultsByName("Some Name").then(function(results){
    // access results here by chaining to the returned promise
});

You can see more examples of using parse promises with queries in Parse's own blog post about it.

Using ExcelDataReader to read Excel data starting from a particular cell

I found this useful to read from a specific column and row:

FileStream stream = File.Open(@"C:\Users\Desktop\ExcelDataReader.xlsx", FileMode.Open, FileAccess.Read);
IExcelDataReader excelReader = ExcelReaderFactory.CreateOpenXmlReader(stream);
DataSet result = excelReader.AsDataSet();
excelReader.IsFirstRowAsColumnNames = true;         
DataTable dt = result.Tables[0];
string text = dt.Rows[1][0].ToString();

What is ".NET Core"?

Microsoft recognized the future web open source paradigm and decided to open .NET to other operating systems. .NET Core is a .NET Framework for Mac and Linux. It is a “lightweight” .NET Framework, so some features/libraries are missing.

On Windows, I would still run .NET Framework and Visual Studio 2015. .NET Core is more friendly with the open source world like Node.js, npm, Yeoman, Docker, etc.

You can develop full-fledged web sites and RESTful APIs on Mac or Linux with Visual Studio Code + .NET Core which wasn't possible before. So if you love Mac or Ubuntu and you are a .NET developer then go ahead and set it up.

For Mono vs. .NET Core, Mono was developed as a .NET Framework for Linux which is now acquired by Microsoft (company called Xamarin) and used in mobile development. Eventually, Microsoft may merge/migrate Mono to .NET Core. I would not worry about Mono right now.

Can you get the number of lines of code from a GitHub repository?

You can clone just the latest commit using git clone --depth 1 <url> and then perform your own analysis using Linguist, the same software Github uses. That's the only way I know you're going to get lines of code.

Another option is to use the API to list the languages the project uses. It doesn't give them in lines but in bytes. For example...

$ curl https://api.github.com/repos/evalEmpire/perl5i/languages
{
  "Perl": 274835
}

Though take that with a grain of salt, that project includes YAML and JSON which the web site acknowledges but the API does not.

Finally, you can use code search to ask which files match a given language. This example asks which files in perl5i are Perl. https://api.github.com/search/code?q=language:perl+repo:evalEmpire/perl5i. It will not give you lines, and you have to ask for the file size separately using the returned url for each file.

SMTPAuthenticationError when sending mail using gmail and python

Your code looks correct. Try logging in through your browser and if you are able to access your account come back and try your code again. Just make sure that you have typed your username and password correct

EDIT: Google blocks sign-in attempts from apps which do not use modern security standards (mentioned on their support page). You can however, turn on/off this safety feature by going to the link below:

Go to this link and select Turn On
https://www.google.com/settings/security/lesssecureapps

Converting list to numpy array

If you have a list of lists, you only needed to use ...

import numpy as np
...
npa = np.asarray(someListOfLists, dtype=np.float32)

per this LINK in the scipy / numpy documentation. You just needed to define dtype inside the call to asarray.

How to exclude *AutoConfiguration classes in Spring Boot JUnit tests?

I think that using the @EnableAutoConfiguration annotation on a test class won't work if you are using @SpringApplicationConfiguration to load your Application class. The thing is that you already have a @EnableAutoConfiguration annotation in the Application class that does not exclude the CrshAutoConfiguration.Spring uses that annotation instead of the one on your test class to do the auto configuration of your beans.

I think that your best bet is to use a different application context for your tests and exclude the CrshAutoConfiguration in that class.

I did some tests and it seems that @EnableAutoConfiguration on the test class is completely ignore if you are using the @SpringApplicationConfiguration annotation and the SpringJUnit4ClassRunner.

Entity Framework Queryable async

The problem seems to be that you have misunderstood how async/await work with Entity Framework.

About Entity Framework

So, let's look at this code:

public IQueryable<URL> GetAllUrls()
{
    return context.Urls.AsQueryable();
}

and example of it usage:

repo.GetAllUrls().Where(u => <condition>).Take(10).ToList()

What happens there?

  1. We are getting IQueryable object (not accessing database yet) using repo.GetAllUrls()
  2. We create a new IQueryable object with specified condition using .Where(u => <condition>
  3. We create a new IQueryable object with specified paging limit using .Take(10)
  4. We retrieve results from database using .ToList(). Our IQueryable object is compiled to sql (like select top 10 * from Urls where <condition>). And database can use indexes, sql server send you only 10 objects from your database (not all billion urls stored in database)

Okay, let's look at first code:

public async Task<IQueryable<URL>> GetAllUrlsAsync()
{
    var urls = await context.Urls.ToListAsync();
    return urls.AsQueryable();
}

With the same example of usage we got:

  1. We are loading in memory all billion urls stored in your database using await context.Urls.ToListAsync();.
  2. We got memory overflow. Right way to kill your server

About async/await

Why async/await is preferred to use? Let's look at this code:

var stuff1 = repo.GetStuff1ForUser(userId);
var stuff2 = repo.GetStuff2ForUser(userId);
return View(new Model(stuff1, stuff2));

What happens here?

  1. Starting on line 1 var stuff1 = ...
  2. We send request to sql server that we want to get some stuff1 for userId
  3. We wait (current thread is blocked)
  4. We wait (current thread is blocked)
  5. .....
  6. Sql server send to us response
  7. We move to line 2 var stuff2 = ...
  8. We send request to sql server that we want to get some stuff2 for userId
  9. We wait (current thread is blocked)
  10. And again
  11. .....
  12. Sql server send to us response
  13. We render view

So let's look to an async version of it:

var stuff1Task = repo.GetStuff1ForUserAsync(userId);
var stuff2Task = repo.GetStuff2ForUserAsync(userId);
await Task.WhenAll(stuff1Task, stuff2Task);
return View(new Model(stuff1Task.Result, stuff2Task.Result));

What happens here?

  1. We send request to sql server to get stuff1 (line 1)
  2. We send request to sql server to get stuff2 (line 2)
  3. We wait for responses from sql server, but current thread isn't blocked, he can handle queries from another users
  4. We render view

Right way to do it

So good code here:

using System.Data.Entity;

public IQueryable<URL> GetAllUrls()
{
   return context.Urls.AsQueryable();
}

public async Task<List<URL>> GetAllUrlsByUser(int userId) {
   return await GetAllUrls().Where(u => u.User.Id == userId).ToListAsync();
}

Note, than you must add using System.Data.Entity in order to use method ToListAsync() for IQueryable.

Note, that if you don't need filtering and paging and stuff, you don't need to work with IQueryable. You can just use await context.Urls.ToListAsync() and work with materialized List<Url>.

Add column in dataframe from list

IIUC, if you make your (unfortunately named) List into an ndarray, you can simply index into it naturally.

>>> import numpy as np
>>> m = np.arange(16)*10
>>> m[df.A]
array([  0,  40,  50,  60, 150, 150, 140, 130])
>>> df["D"] = m[df.A]
>>> df
    A   B   C    D
0   0 NaN NaN    0
1   4 NaN NaN   40
2   5 NaN NaN   50
3   6 NaN NaN   60
4  15 NaN NaN  150
5  15 NaN NaN  150
6  14 NaN NaN  140
7  13 NaN NaN  130

Here I built a new m, but if you use m = np.asarray(List), the same thing should work: the values in df.A will pick out the appropriate elements of m.


Note that if you're using an old version of numpy, you might have to use m[df.A.values] instead-- in the past, numpy didn't play well with others, and some refactoring in pandas caused some headaches. Things have improved now.

How to insert a line break <br> in markdown

Try adding 2 spaces (or a backslash \) after the first line:

[Name of link](url)
My line of text\

Visually:

[Name of link](url)<space><space>
My line of text\

Output:

<p><a href="url">Name of link</a><br>
My line of text<br></p>

How to pass an array to a function in VBA?

Your function worked for me after changing its declaration to this ...

Function processArr(Arr As Variant) As String

You could also consider a ParamArray like this ...

Function processArr(ParamArray Arr() As Variant) As String
    'Dim N As Variant
    Dim N As Long
    Dim finalStr As String
    For N = LBound(Arr) To UBound(Arr)
        finalStr = finalStr & Arr(N)
    Next N
    processArr = finalStr
End Function

And then call the function like this ...

processArr("foo", "bar")

libc++abi.dylib: terminating with uncaught exception of type NSException (lldb)

In my case, it was InterfaceBuilder. I had copied some Views from another ViewController which messed up the constraints.

In InterfaceBuilder I had the red arrow error on the ViewController.

During execution the app crashed.

OperationalError, no such column. Django

I did the following

  1. Delete my db.sqlite3 database
  2. python manage.py makemigrations
  3. python manage.py migrate

It renewed the database and fixed the issues without affecting my project. Please note you might need to do python manage.py createsuperuser because it will affect all your objects being created.

No found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations:

Add the annotation @Repository to the implementation of UserDaoImpl

@Repository
public class UserDaoImpl implements UserDao {
    private static Log log = LogFactory.getLog(UserDaoImpl.class);

    @Autowired
    @Qualifier("sessionFactory")
    private LocalSessionFactoryBean sessionFactory;

    //...

}

Proper way to set response status and JSON content in a REST API made with nodejs and express

res.sendStatus(status) has been added as of version 4.9.0

you can use one of these res.sendStatus() || res.status() methods

below is difference in between res.sendStatus() || res.status()


res.sendStatus(200) // equivalent to res.status(200).send('OK')
res.sendStatus(403) // equivalent to res.status(403).send('Forbidden')
res.sendStatus(404) // equivalent to res.status(404).send('Not Found')
res.sendStatus(500) // equivalent to res.status(500).send('Internal Server Error')

I hope someone finds this helpful thanks

Warning: Attempt to present * on * whose view is not in the window hierarchy - swift

Swift 3.

Call this function to get the topmost view controller, then have that view controller present.

func topMostController() -> UIViewController {
    var topController: UIViewController = UIApplication.shared.keyWindow!.rootViewController!
        while (topController.presentedViewController != nil) {
            topController = topController.presentedViewController!
        }
        return topController
    }

Usage:

let topVC = topMostController()
let vcToPresent = self.storyboard!.instantiateViewController(withIdentifier: "YourVCStoryboardID") as! YourViewController
topVC.present(vcToPresent, animated: true, completion: nil)

MySQL does not start when upgrading OSX to Yosemite or El Capitan

You will sometimes miss previous data if you try to install new version.. Please use the following in your terminal and I guarantee that mySql will start running in no time..

sudo /Applications/XAMPP/xamppfiles/bin/mysql.server start

Remember, it will ask for your Machine password and not mysql password..

Uses for the '&quot;' entity in HTML

It is likely because they used a single function for escaping attributes and text nodes. &amp; doesn't do any harm so why complicate your code and make it more error-prone by having two escaping functions and having to pick between them?

Java ElasticSearch None of the configured nodes are available

This one did work for me in ES 1.7.5:

import org.elasticsearch.action.index.IndexResponse;
import org.elasticsearch.client.Client;
import org.elasticsearch.client.transport.TransportClient;
import org.elasticsearch.common.settings.ImmutableSettings;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.common.transport.InetSocketTransportAddress;
import org.elasticsearch.common.xcontent.XContentBuilder;

public static void main(String[] args) throws IOException  {
    Settings settings = ImmutableSettings.settingsBuilder()
            .put("client.transport.sniff",true)
            .put("cluster.name","elasticcluster").build();

    Client client = new TransportClient(settings)
            .addTransportAddress(new InetSocketTransportAddress("[ipaddress]",9300));
    XContentBuilder builder = null;
    try {
        builder = jsonBuilder().startObject().field("user", "testdata").field("postdata",new Date()).field("message","testmessage")
                .endObject();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

    System.out.println(builder.string());

    IndexResponse response = client.prepareIndex("twitter","tweet","1").setSource(builder).execute().actionGet();

    client.close();

}

git am error: "patch does not apply"

Had several modules complain about patch does not apply. One thing I was missing out was that the branches had become stale. After the git merge master generated the patch files using git diff master BRANCH > file.patch. Going to the vanilla branch was able to apply the patch with git apply file.patch

iOS8 Beta Ad-Hoc App Download (itms-services)

Specify a 'display-image' and 'full-size-image' as described here: http://www.informit.com/articles/article.aspx?p=1829415&seqNum=16

iOS8 requires these images

How can I make window.showmodaldialog work in chrome 37?

The window.showModalDialog is deprecated (Intent to Remove: window.showModalDialog(), Removing showModalDialog from the Web platform). [...]The latest plan is to land the showModalDialog removal in Chromium 37. This means the feature will be gone in Opera 24 and Chrome 37, both of which should be released in September.[...]

Operator overloading ==, !=, Equals

In fact, this is a "how to" subject. So, here is the reference implementation:

    public class BOX
    {
        double height, length, breadth;

        public static bool operator == (BOX b1, BOX b2)
        {
            if ((object)b1 == null)
                return (object)b2 == null;

            return b1.Equals(b2);
        }

        public static bool operator != (BOX b1, BOX b2)
        {
            return !(b1 == b2);
        }

        public override bool Equals(object obj)
        {
            if (obj == null || GetType() != obj.GetType())
                return false;

            var b2 = (BOX)obj;
            return (length == b2.length && breadth == b2.breadth && height == b2.height);
        }

        public override int GetHashCode()
        {
            return height.GetHashCode() ^ length.GetHashCode() ^ breadth.GetHashCode();
        }
    }

REF: https://msdn.microsoft.com/en-us/library/336aedhh(v=vs.100).aspx#Examples

UPDATE: the cast to (object) in the operator == implementation is important, otherwise, it would re-execute the operator == overload, leading to a stackoverflow. Credits to @grek40.

This (object) cast trick is from Microsoft String == implementaiton. SRC: https://github.com/Microsoft/referencesource/blob/master/mscorlib/system/string.cs#L643

python 2.7: cannot pip on windows "bash: pip: command not found"

If this is for Cygwin, it installs "pip" as "pip2". Just create a softlink to "pip2" in the same location where "pip2" is installed.

Disable all dialog boxes in Excel while running VB script?

From Excel Macro Security - www.excelfunctions.net:

Macro Security in Excel 2007, 2010 & 2013:

.....

The different Excel file types provided by the latest versions of Excel make it clear when workbook contains macros, so this in itself is a useful security measure. However, Excel also has optional macro security settings, which are controlled via the options menu. These are :

'Disable all macros without notification'

  • This setting does not allow any macros to run. When you open a new Excel workbook, you are not alerted to the fact that it contains macros, so you may not be aware that this is the reason a workbook does not work as expected.

'Disable all macros with notification'

  • This setting prevents macros from running. However, if there are macros in a workbook, a pop-up is displayed, to warn you that the macros exist and have been disabled.

'Disable all macros except digitally signed macros'

  • This setting only allow macros from trusted sources to run. All other macros do not run. When you open a new Excel workbook, you are not alerted to the fact that it contains macros, so you may not be aware that this is the reason a workbook does not work as expected.

'Enable all macros'

  • This setting allows all macros to run. When you open a new Excel workbook, you are not alerted to the fact that it contains macros and may not be aware of macros running while you have the file open.

If you trust the macros and are ok with enabling them, select this option:

'Enable all macros'

and this dialog box should not show up for macros.

As for the dialog for saving, after noting that this was running on Excel for Mac 2011, I came across the following question on SO, StackOverflow - Suppress dialog when using VBA to save a macro containing Excel file (.xlsm) as a non macro containing file (.xlsx). From it, removing the dialog does not seem to be possible, except for possibly by some Keyboard Input simulation. I would post another question to inquire about that. Sorry I could only get you halfway. The other option would be to use a Windows computer with Microsoft Excel, though I'm not sure if that is a option for you in this case.

What's the difference between abstraction and encapsulation?

Developer A, who is inherently utilising the concept of abstraction will use a module/library function/widget, concerned only with what it does (and what it will be used for) but not how it does it. The interface of that module/library function/widget (the 'levers' the Developer A is allowed to pull/push) is the personification of that abstraction.

Developer B, who is seeking to create such a module/function/widget will utilise the concept of encapsulation to ensure Developer A (and any other developer who uses the widget) can take advantage of the resulting abstraction. Developer B is most certainly concerned with how the widget does what it does.

TLDR;

  • Abstraction - I care about what something does, but not how it does it.
  • Encapsulation - I care about how something does what it does such that others only need to care about what it does.

(As a loose generalisation, to abstract something, you must encapsulate something else. And by encapsulating something, you have created an abstraction.)

Android Studio Google JAR file causing GC overhead limit exceeded error

I tried all the solutions mentioned above, but I was still facing the issue. Finally I stumbled upon the following which resolved the issue.

(On MacOS) Went to Preferences -> Memory Settings -> Find existing grade demon(s) -> Stopped all of them.

Load a UIView from nib in Swift

I prefer the below extension

extension UIView {
    class var instanceFromNib: Self {
        return Bundle(for: Self.self)
            .loadNibNamed(String(describing: Self.self), owner: nil, options: nil)?.first as! Self
    }
}

The difference between this and the top answered extension is you don't need to store it an constant or variable.

class TitleView: UIView { }

extension UIView {
    class var instanceFromNib: Self {
        return Bundle(for: Self.self)
            .loadNibNamed(String(describing: Self.self), owner: nil, options: nil)?.first as! Self
    }
}

self.navigationItem.titleView = TitleView.instanceFromNib

Using $window or $location to Redirect in AngularJS

It might help you! demo

AngularJs Code-sample

var app = angular.module('urlApp', []);
app.controller('urlCtrl', function ($scope, $log, $window) {
    $scope.ClickMeToRedirect = function () {
        var url = "http://" + $window.location.host + "/Account/Login";
        $log.log(url);
        $window.location.href = url;
    };
});

HTML Code-sample

<div ng-app="urlApp">
    <div ng-controller="urlCtrl">
        Redirect to <a href="#" ng-click="ClickMeToRedirect()">Click Me!</a>
    </div>
</div>

chart.js load totally new data

Not is necesary destroy the chart. Try with this

function removeData(chart) {

        let total = chart.data.labels.length;

        while (total >= 0) {
            chart.data.labels.pop();
            chart.data.datasets[0].data.pop();
            total--;
        }

        chart.update();
    }

Remove all constraints affecting a UIView

Based on previous answers (swift 4)

You can use immediateConstraints when you don't want to crawl entire hierarchies.

extension UIView {
/**
 * Deactivates immediate constraints that target this view (self + superview)
 */
func deactivateImmediateConstraints(){
    NSLayoutConstraint.deactivate(self.immediateConstraints)
}
/**
 * Deactivates all constrains that target this view
 */
func deactiveAllConstraints(){
    NSLayoutConstraint.deactivate(self.allConstraints)
}
/**
 * Gets self.constraints + superview?.constraints for this particular view
 */
var immediateConstraints:[NSLayoutConstraint]{
    let constraints = self.superview?.constraints.filter{
        $0.firstItem as? UIView === self || $0.secondItem as? UIView === self
        } ?? []
    return self.constraints + constraints
}
/**
 * Crawls up superview hierarchy and gets all constraints that affect this view
 */
var allConstraints:[NSLayoutConstraint] {
    var view: UIView? = self
    var constraints:[NSLayoutConstraint] = []
    while let currentView = view {
        constraints += currentView.constraints.filter {
            return $0.firstItem as? UIView === self || $0.secondItem as? UIView === self
        }
        view = view?.superview
    }
    return constraints
}
}

SSL Error: unable to get local issuer certificate

If you are a linux user Update node to a later version by running

sudo apt update

 sudo apt install build-essential checkinstall libssl-dev

curl -o- https://raw.githubusercontent.com/creationix/nvm/v0.35.1/install.sh | bash

nvm --version

nvm ls

nvm ls-remote

nvm install [version.number]

this should solve your problem

ansible: lineinfile for several lines?

To add multiple lines you can use blockfile:

- name: Add mappings to /etc/hosts
  blockinfile:
    path: /etc/hosts
    block: |
      '10.10.10.10  server.example.com'
      '10.10.10.11  server1.example.com'

to Add one line you can use lininfile:

- name: server.example.com in /etc/hosts
  lineinfile:
    path: /etc/hosts
    line: '192.0.2.42 server.example.com server'
    state: present

java.lang.Exception: No runnable methods exception in running JUnits

I also faced this issue and failed to figure out the reason for the same for sometimes. Later i found that auto import issue using IDE. That is imports of the program.

Basically i was using eclipse IDE. And I was importing a wrong class "org.junit.jupiter.api.Test" into the program instead of required class "org.junit.Test". Hence check your imports before running any programs.

413 Request Entity Too Large - File Upload Issue

Assuming that you made the necessary changes in your php.ini files:

You can resolve the issue by adding the following line in your nginx.conf file found in the following path:

/etc/nginx/nginx.conf

then edit the file using vim text editor as follows:

vi /etc/nginx/nginx.conf

and add client_max_body_size with a large enough value, for example:

client_max_body_size 20MB;

After that make sure you save using :xi or :wq

And then restart your nginx.

That's it.

Worked for me, hope this helps.

how to get curl to output only http response body (json) and no other headers etc

#!/bin/bash

req=$(curl -s -X GET http://host:8080/some/resource -H "Accept: application/json") 2>&1
echo "${req}"

creating custom tableview cells in swift

[1] First Design your tableview cell in StoryBoard.

[2] Put below table view delegate method

//MARK: - Tableview Delegate Methods

func numberOfSectionsInTableView(tableView: UITableView) -> Int
{
    return 1
}

func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int
{

    return <“Your Array”>
}


func tableView(tableView: UITableView, heightForRowAtIndexPath indexPath: NSIndexPath) -> CGFloat
{

    var totalHeight : CGFloat = <cell name>.<label name>.frame.origin.y    

    totalHeight +=   UpdateRowHeight(<cell name>.<label name>, textToAdd: <your array>[indexPath.row])    

    return totalHeight
}


func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell
{


    var cell : <cell name>! = tableView.dequeueReusableCellWithIdentifier(“<cell identifire>”, forIndexPath: indexPath) as! CCell_VideoCall

    if(cell == nil)
    {
        cell = NSBundle.mainBundle().loadNibNamed("<cell identifire>", owner: self, options: nil)[0] as! <cell name>;
    }


    <cell name>.<label name>.text = <your array>[indexPath.row] as? String



    return cell as <cell name>
}

//MARK: - Custom Methods

func UpdateRowHeight ( ViewToAdd : UILabel , textToAdd : AnyObject  ) -> CGFloat{


    var actualHeight : CGFloat = ViewToAdd.frame.size.height

    if let strName : String? = (textToAdd as? String)
        where !strName!.isEmpty
    {

        actualHeight = heightForView1(strName!, font: ViewToAdd.font, width: ViewToAdd.frame.size.width, DesignTimeHeight: actualHeight )

    }
    return actualHeight
}

self.tableView.reloadData() not working in Swift

Beside the obvious reloadData from UI/Main Thread (whatever Apple calls it), in my case, I had forgotten to also update the SECTIONS info. Therefor it did not detect any new sections!

Creating NSData from NSString in Swift

Swift 4 & 3

Creating Data object from String object has been changed in Swift 3. Correct version now is:

let data = "any string".data(using: .utf8)

What does an exclamation mark mean in the Swift language?

ASK YOURSELF

  • Does the type person? have an apartment member/property? OR
  • Does the type person have an apartment member/property?

If you can't answer this question, then continue reading:

To understand you may need super-basic level of understanding of Generics. See here. A lot of things in Swift are written using Generics. Optionals included

The code below has been made available from this Stanford video. Highly recommend you to watch the first 5 minutes

An Optional is an enum with only 2 cases

enum Optional<T>{
    case None
    case Some(T)
}

let x: String? = nil //actually means:

let x = Optional<String>.None

let x :String? = "hello" //actually means:

let x = Optional<String>.Some("hello")

var y = x! // actually means:

switch x {
case .Some(let value): y = value
case .None: // Raise an exception
}

Optional binding:

let x:String? = something
if let y = x {
    // do something with y
}
//Actually means:

switch x{
case .Some(let y): print)(y) // or whatever else you like using 
case .None: break
}

when you say var john: Person? You actually mean such:

enum Optional<Person>{
case .None
case .Some(Person)
}

Does the above enum have any property named apartment? Do you see it anywhere? It's not there at all! However if you unwrap it ie do person! then you can ... what it does under the hood is : Optional<Person>.Some(Person(name: "John Appleseed"))


Had you defined var john: Person instead of: var john: Person? then you would have no longer needed to have the ! used, because Person itself does have a member of apartment


As a future discussion on why using ! to unwrap is sometimes not recommended see this Q&A

Laravel Check If Related Model Exists

I had to completely refactor my code when I updated my PHP version to 7.2+ because of bad usage of the count($x) function. This is a real pain and its also extremely scary as there are hundreds usages, in different scenarios and there is no one rules fits all..

Rules I followed to refactor everything, examples:

$x = Auth::user()->posts->find(6); (check if user has a post id=6 using ->find())

[FAILS] if(count($x)) { return 'Found'; } 
[GOOD] if($x) { return 'Found'; }

$x = Auth::user()->profile->departments; (check if profile has some departments, there can have many departments)

[FAILS] if(count($x)) { return 'Found'; }
[GOOD] if($x->count()) { return 'Found'; }

$x = Auth::user()->profile->get(); (check if user has a profile after using a ->get())

[FAILS] if(count($x)) { return 'Found'; }
[GOOD] if($x->count()) { return 'Found'; }

Hopes this can help, even 5 years after the question has been asked, this stackoverflow post has helped me a lot!

Razor MVC Populating Javascript array with Model Array

This is possible, you just need to loop through the razor collection

<script type="text/javascript">

    var myArray = [];

    @foreach (var d in Model.data)
    {
        @:myArray.push("@d");
    }

    alert(myArray);

</script>

Hope this helps

Facebook Graph API v2.0+ - /me/friends returns empty, or only friends who also use my application

In the Facebook SDK Graph API v2.0 or above, you must request the user_friends permission from each user in the time of Facebook login since user_friends is no longer included by default in every login; we have to add that.

Each user must grant the user_friends permission in order to appear in the response to /me/friends.

let fbLoginManager : FBSDKLoginManager = FBSDKLoginManager()
fbLoginManager.loginBehavior = FBSDKLoginBehavior.web
fbLoginManager.logIn(withReadPermissions: ["email","user_friends","public_profile"], from: self) { (result, error) in
    if (error == nil) {

        let fbloginresult : FBSDKLoginManagerLoginResult = result!
        if fbloginresult.grantedPermissions != nil {
            if (fbloginresult.grantedPermissions.contains("email")) {
                // Do the stuff
            }
            else {
            }
        }
        else {
        }
    }
}

So at the time of Facebook login, it prompts with a screen which contain all the permissions:

Enter image description here

If the user presses the Continue button, the permissions will be set. When you access the friends list using Graph API, your friends who logged into the application as above will be listed

if ((FBSDKAccessToken.current()) != nil) {
    FBSDKGraphRequest(graphPath: "/me/friends", parameters: ["fields" : "id,name"]).start(completionHandler: { (connection, result, error) -> Void in
        if (error == nil) {

            print(result!)
        }
    })
}

The output will contain the users who granted the user_friends permission at the time of login to your application through Facebook.

{
    data = (
             {
                 id = xxxxxxxxxx;
                 name = "xxxxxxxx";
             }
           );
    paging = {
        cursors = {
            after = xxxxxx;
            before = xxxxxxx;
        };
    };
    summary = {
        "total_count" = 8;
    };
}

Laravel: Using try...catch with DB::transaction()

You could wrapping the transaction over try..catch or even reverse them, here my example code I used to in laravel 5,, if you look deep inside DB:transaction() in Illuminate\Database\Connection that the same like you write manual transaction.

Laravel Transaction

public function transaction(Closure $callback)
    {
        $this->beginTransaction();

        try {
            $result = $callback($this);

            $this->commit();
        }

        catch (Exception $e) {
            $this->rollBack();

            throw $e;
        } catch (Throwable $e) {
            $this->rollBack();

            throw $e;
        }

        return $result;
    }

so you could write your code like this, and handle your exception like throw message back into your form via flash or redirect to another page. REMEMBER return inside closure is returned in transaction() so if you return redirect()->back() it won't redirect immediately, because the it returned at variable which handle the transaction.

Wrap Transaction

$result = DB::transaction(function () use ($request, $message) {
   try{

      // execute query 1
      // execute query 2
      // ..

      return redirect(route('account.article'));

   } catch (\Exception $e) {
       return redirect()->back()->withErrors(['error' => $e->getMessage()]);
    }
 });

// redirect the page
return $result;

then the alternative is throw boolean variable and handle redirect outside transaction function or if your need to retrieve why transaction failed you can get it from $e->getMessage() inside catch(Exception $e){...}

How to resolve this System.IO.FileNotFoundException

Check all the references carefully

  • Version remains same on target machine and local machine
  • If assembly is referenced from GAC, ensure that proper version is loaded

For me cleaning entire solution by deleting manually, updating (removing and adding) references again with version in sync with target machine and then building with with Copy Local > False for GAC assemblies solves the problem.

Apache 2.4 - Request exceeded the limit of 10 internal redirects due to probable configuration error

You're getting into looping most likely due to these rules:

RewriteRule ^(.*\.php)$ $1 [L]
RewriteRule ^(wp-(content|admin|includes).*) $1 [L]

Just comment it out and try again in a new browser.

How are people unit testing with Entity Framework 6, should you bother?

This is a topic I'm very interested in. There are many purists who say that you shouldn't test technologies such as EF and NHibernate. They are right, they're already very stringently tested and as a previous answer stated it's often pointless to spend vast amounts of time testing what you don't own.

However, you do own the database underneath! This is where this approach in my opinion breaks down, you don't need to test that EF/NH are doing their jobs correctly. You need to test that your mappings/implementations are working with your database. In my opinion this is one of the most important parts of a system you can test.

Strictly speaking however we're moving out of the domain of unit testing and into integration testing but the principles remain the same.

The first thing you need to do is to be able to mock your DAL so your BLL can be tested independently of EF and SQL. These are your unit tests. Next you need to design your Integration Tests to prove your DAL, in my opinion these are every bit as important.

There are a couple of things to consider:

  1. Your database needs to be in a known state with each test. Most systems use either a backup or create scripts for this.
  2. Each test must be repeatable
  3. Each test must be atomic

There are two main approaches to setting up your database, the first is to run a UnitTest create DB script. This ensures that your unit test database will always be in the same state at the beginning of each test (you may either reset this or run each test in a transaction to ensure this).

Your other option is what I do, run specific setups for each individual test. I believe this is the best approach for two main reasons:

  • Your database is simpler, you don't need an entire schema for each test
  • Each test is safer, if you change one value in your create script it doesn't invalidate dozens of other tests.

Unfortunately your compromise here is speed. It takes time to run all these tests, to run all these setup/tear down scripts.

One final point, it can be very hard work to write such a large amount of SQL to test your ORM. This is where I take a very nasty approach (the purists here will disagree with me). I use my ORM to create my test! Rather than having a separate script for every DAL test in my system I have a test setup phase which creates the objects, attaches them to the context and saves them. I then run my test.

This is far from the ideal solution however in practice I find it's a LOT easier to manage (especially when you have several thousand tests), otherwise you're creating massive numbers of scripts. Practicality over purity.

I will no doubt look back at this answer in a few years (months/days) and disagree with myself as my approaches have changed - however this is my current approach.

To try and sum up everything I've said above this is my typical DB integration test:

[Test]
public void LoadUser()
{
  this.RunTest(session => // the NH/EF session to attach the objects to
  {
    var user = new UserAccount("Mr", "Joe", "Bloggs");
    session.Save(user);
    return user.UserID;
  }, id => // the ID of the entity we need to load
  {
     var user = LoadMyUser(id); // load the entity
     Assert.AreEqual("Mr", user.Title); // test your properties
     Assert.AreEqual("Joe", user.Firstname);
     Assert.AreEqual("Bloggs", user.Lastname);
  }
}

The key thing to notice here is that the sessions of the two loops are completely independent. In your implementation of RunTest you must ensure that the context is committed and destroyed and your data can only come from your database for the second part.

Edit 13/10/2014

I did say that I'd probably revise this model over the upcoming months. While I largely stand by the approach I advocated above I've updated my testing mechanism slightly. I now tend to create the entities in in the TestSetup and TestTearDown.

[SetUp]
public void Setup()
{
  this.SetupTest(session => // the NH/EF session to attach the objects to
  {
    var user = new UserAccount("Mr", "Joe", "Bloggs");
    session.Save(user);
    this.UserID =  user.UserID;
  });
}

[TearDown]
public void TearDown()
{
   this.TearDownDatabase();
}

Then test each property individually

[Test]
public void TestTitle()
{
     var user = LoadMyUser(this.UserID); // load the entity
     Assert.AreEqual("Mr", user.Title);
}

[Test]
public void TestFirstname()
{
     var user = LoadMyUser(this.UserID);
     Assert.AreEqual("Joe", user.Firstname);
}

[Test]
public void TestLastname()
{
     var user = LoadMyUser(this.UserID);
     Assert.AreEqual("Bloggs", user.Lastname);
}

There are several reasons for this approach:

  • There are no additional database calls (one setup, one teardown)
  • The tests are far more granular, each test verifies one property
  • Setup/TearDown logic is removed from the Test methods themselves

I feel this makes the test class simpler and the tests more granular (single asserts are good)

Edit 5/3/2015

Another revision on this approach. While class level setups are very helpful for tests such as loading properties they are less useful where the different setups are required. In this case setting up a new class for each case is overkill.

To help with this I now tend to have two base classes SetupPerTest and SingleSetup. These two classes expose the framework as required.

In the SingleSetup we have a very similar mechanism as described in my first edit. An example would be

public TestProperties : SingleSetup
{
  public int UserID {get;set;}

  public override DoSetup(ISession session)
  {
    var user = new User("Joe", "Bloggs");
    session.Save(user);
    this.UserID = user.UserID;
  }

  [Test]
  public void TestLastname()
  {
     var user = LoadMyUser(this.UserID); // load the entity
     Assert.AreEqual("Bloggs", user.Lastname);
  }

  [Test]
  public void TestFirstname()
  {
       var user = LoadMyUser(this.UserID);
       Assert.AreEqual("Joe", user.Firstname);
  }
}

However references which ensure that only the correct entites are loaded may use a SetupPerTest approach

public TestProperties : SetupPerTest
{
   [Test]
   public void EnsureCorrectReferenceIsLoaded()
   {
      int friendID = 0;
      this.RunTest(session =>
      {
         var user = CreateUserWithFriend();
         session.Save(user);
         friendID = user.Friends.Single().FriendID;
      } () =>
      {
         var user = GetUser();
         Assert.AreEqual(friendID, user.Friends.Single().FriendID);
      });
   }
   [Test]
   public void EnsureOnlyCorrectFriendsAreLoaded()
   {
      int userID = 0;
      this.RunTest(session =>
      {
         var user = CreateUserWithFriends(2);
         var user2 = CreateUserWithFriends(5);
         session.Save(user);
         session.Save(user2);
         userID = user.UserID;
      } () =>
      {
         var user = GetUser(userID);
         Assert.AreEqual(2, user.Friends.Count());
      });
   }
}

In summary both approaches work depending on what you are trying to test.

How to use Regular Expressions (Regex) in Microsoft Excel both in-cell and loops

I needed to use this as a cell function (like SUM or VLOOKUP) and found that it was easy to:

  1. Make sure you are in a Macro Enabled Excel File (save as xlsm).
  2. Open developer tools Alt + F11
  3. Add Microsoft VBScript Regular Expressions 5.5 as in other answers
  4. Create the following function either in workbook or in its own module:

    Function REGPLACE(myRange As Range, matchPattern As String, outputPattern As String) As Variant
        Dim regex As New VBScript_RegExp_55.RegExp
        Dim strInput As String
    
        strInput = myRange.Value
    
        With regex
            .Global = True
            .MultiLine = True
            .IgnoreCase = False
            .Pattern = matchPattern
        End With
    
        REGPLACE = regex.Replace(strInput, outputPattern)
    
    End Function
    
  5. Then you can use in cell with =REGPLACE(B1, "(\w) (\d+)", "$1$2") (ex: "A 243" to "A243")

LINQ select one field from list of DTO objects to array

You can select all Sku elements of your myLines list and then convert the result to an array.

string[] mySKUsArray = myLines.Select(x=>x.Sku).ToArray();

Conditionally formatting if multiple cells are blank (no numerics throughout spreadsheet )

The steps you took are not appropriate because the cell you want formatted is not the trigger cell (presumably won't normally be blank). In your case you want formatting to apply to one set of cells according to the status of various other cells. I suggest with data layout as shown in the image (and with thanks to @xQbert for a start on a suitable formula) you select ColumnA and:

HOME > Styles - Conditional Formatting, New Rule..., Use a formula to determine which cells to format and Format values where this formula is true::

=AND(LEN(E1)*LEN(F1)*LEN(G1)*LEN(H1)=0,NOT(ISBLANK(A1)))

Format..., select formatting, OK, OK.

SO22487695 example

where I have filled yellow the cells that are triggering the red fill result.

How to correctly use Html.ActionLink with ASP.NET MVC 4 Areas

How I redirect to an area is add it as a parameter

@Html.Action("Action", "Controller", new { area = "AreaName" })

for the href portion of a link I use

@Url.Action("Action", "Controller", new { area = "AreaName" })

java.lang.ClassNotFoundException: Didn't find class on path: dexpathlist

in my case, I define the Activity in Manifest.xml and forgot to create any activity. So I created Activity and define it in manifest and my error solved!

Can you blur the content beneath/behind a div?

you can do this with css3, this blurs the whole element

div (or whatever element) {
  -webkit-filter: blur(5px);
  -moz-filter: blur(5px);
  -o-filter: blur(5px);
  -ms-filter: blur(5px);
  filter: blur(5px);
}

Fiddle: http://jsfiddle.net/H4DU4/

How to auto import the necessary classes in Android Studio with shortcut?

Go on the missing declaration with cursor and press alt+enter enter image description here

How to send data with angularjs $http.delete() request?

My suggestion:

$http({
    method: 'DELETE',
    url: '/roles/' + roleid,
    data: {
        user: userId
    },
    headers: {
        'Content-type': 'application/json;charset=utf-8'
    }
})
.then(function(response) {
    console.log(response.data);
}, function(rejection) {
    console.log(rejection.data);
});

Why when a constructor is annotated with @JsonCreator, its arguments must be annotated with @JsonProperty?

When I understand this correctly, you replace the default constructor with a parameterized one and therefore have to describe the JSON keys which are used to call the constructor with.

'Invalid update: invalid number of rows in section 0

Swift Version --> Remove the object from your data array before you call

func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCellEditingStyle, forRowAt indexPath: IndexPath) {
    if editingStyle == .delete {
        print("Deleted")

        currentCart.remove(at: indexPath.row) //Remove element from your array 
        self.tableView.deleteRows(at: [indexPath], with: .automatic)
    }
}

Bootstrap 3: Using img-circle, how to get circle from non-square image?

I see that this post is a little out of date but still... I can show you and everyone else (who is in the same situation as I was this day) how i did it.

First of all, you need html like this:

<div class="circle-avatar" style="background-image:url(http://placekitten.com/g/200/400)"></div>

Than your css class will look like this:

div.circle-avatar{
/* make it responsive */
max-width: 100%;
width:100%;
height:auto;
display:block;
/* div height to be the same as width*/
padding-top:100%;

/* make it a circle */
border-radius:50%;

/* Centering on image`s center*/
background-position-y: center;
background-position-x: center;
background-repeat: no-repeat;

/* it makes the clue thing, takes smaller dimension to fill div */
background-size: cover;

/* it is optional, for making this div centered in parent*/
margin: 0 auto;
top: 0;
left: 0;
right: 0;
bottom: 0;
}

It is responsive circle, centered on original image. You can change width and height not to autofill its parent if you want. But keep them equal if you want to have a circle in result.

Link with solution on fiddle

I hope this answer will help struggling people. Bye.

Java Multiple Inheritance

I have a stupid idea:

public class Pegasus {
    private Horse horseFeatures; 
    private Bird birdFeatures; 

   public Pegasus(Horse horse, Bird bird) {
     this.horseFeatures = horse;
     this.birdFeatures = bird;
   }

  public void jump() {
    horseFeatures.jump();
  }

  public void fly() {
    birdFeatures.fly();
  }
}

How to create JSON post to api using C#

Try using Web API HttpClient

    static async Task RunAsync()
    {
        using (var client = new HttpClient())
        {
            client.BaseAddress = new Uri("http://domain.com/");
            client.DefaultRequestHeaders.Accept.Clear();
            client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));


            // HTTP POST
            var obj = new MyObject() { Str = "MyString"};
            response = await client.PostAsJsonAsync("POST URL GOES HERE?", obj );
            if (response.IsSuccessStatusCode)
            {
                response.//.. Contains the returned content.
            }
        }
    }

You can find more details here Web API Clients

Python 'list indices must be integers, not tuple"

Why does the error mention tuples?

Others have explained that the problem was the missing ,, but the final mystery is why does the error message talk about tuples?

The reason is that your:

["pennies", '2.5', '50.0', '.01'] 
["nickles", '5.0', '40.0', '.05']

can be reduced to:

[][1, 2]

as mentioned by 6502 with the same error.

But then __getitem__, which deals with [] resolution, converts object[1, 2] to a tuple:

class C(object):
    def __getitem__(self, k):
        return k

# Single argument is passed directly.
assert C()[0] == 0

# Multiple indices generate a tuple.
assert C()[0, 1] == (0, 1)

and the implementation of __getitem__ for the list built-in class cannot deal with tuple arguments like that.

More examples of __getitem__ action at: https://stackoverflow.com/a/33086813/895245

How to prepare a Unity project for git?

On the Unity Editor open your project and:

  1. Enable External option in Unity ? Preferences ? Packages ? Repository (only if Unity ver < 4.5)
  2. Switch to Visible Meta Files in Edit ? Project Settings ? Editor ? Version Control Mode
  3. Switch to Force Text in Edit ? Project Settings ? Editor ? Asset Serialization Mode
  4. Save Scene and Project from File menu.
  5. Quit Unity and then you can delete the Library and Temp directory in the project directory. You can delete everything but keep the Assets and ProjectSettings directory.

If you already created your empty git repo on-line (eg. github.com) now it's time to upload your code. Open a command prompt and follow the next steps:

cd to/your/unity/project/folder

git init

git add *

git commit -m "First commit"

git remote add origin [email protected]:username/project.git

git push -u origin master

You should now open your Unity project while holding down the Option or the Left Alt key. This will force Unity to recreate the Library directory (this step might not be necessary since I've seen Unity recreating the Library directory even if you don't hold down any key).

Finally have git ignore the Library and Temp directories so that they won’t be pushed to the server. Add them to the .gitignore file and push the ignore to the server. Remember that you'll only commit the Assets and ProjectSettings directories.

And here's my own .gitignore recipe for my Unity projects:

# =============== #
# Unity generated #
# =============== #
Temp/
Obj/
UnityGenerated/
Library/
Assets/AssetStoreTools*

# ===================================== #
# Visual Studio / MonoDevelop generated #
# ===================================== #
ExportedObj/
*.svd
*.userprefs
*.csproj
*.pidb
*.suo
*.sln
*.user
*.unityproj
*.booproj

# ============ #
# OS generated #
# ============ #
.DS_Store
.DS_Store?
._*
.Spotlight-V100
.Trashes
Icon?
ehthumbs.db
Thumbs.db

Installing Bower on Ubuntu

Hi another solution to this problem is to simply add the node nodejs binary folder to your PATH using the following command:

ln -s /usr/bin/nodejs /usr/bin/node

See NPM GitHub for better explanation

ORA-01036: illegal variable name/number when running query through C#

I just spent several days checking parameters because I have to pass 60 to a stored procedure. It turns out that the one of the variable names (which I load into a list and pass to the Oracle Write method I created) had a space in the name at the end. When comparing to the variables in the stored procedure they were the same, but in the editor I used to compare them, I didnt notice the extra space. Drove me crazy for the last 4 days trying everything I could find, and changing even the .net Oracle driver. Just wanted to throw that out here so it can help someone else. We tend to concentrate on the characters and ignore the spaces. . .

CSS height 100% percent not working

You aren't specifying the "height" of your html. When you're assigning a percentage in an element (i.e. divs) the css compiler needs to know the size of the parent element. If you don't assign that, you should see divs without height.

The most common solution is to set the following property in css:

html{
    height: 100%;
    margin: 0;
    padding: 0;
}

You are saying to the html tag (html is the parent of all the html elements) "Take all the height in the HTML document"

I hope I helped you. Cheers

Const in JavaScript: when to use it and is it necessary?

Summary:

const creates an immutable binding meaning const variable identifier is not re-assignable.

const a = "value1";

you cannot re-assign it with

a = "value2";

However, if const identifier holds an object or an array, value of it can be changed as far as we are not re-assigning it.

const x = { a: 1 }

x.a = 2; //is possible and allowed

const numbers = [1, 2];
numbers.push(3); //is possible and allowed

Please note that const is a block-scoped just like let which is not same as var (which is function-scoped)

In short, When something is not likely to change through re-assignment use const else use let or var depending on the scope you would like to have.

It's much easier to reason about the code when it is dead obvious what can be changed through re-assignment and what can't be. Changing a const to a let is dead simple. And going const by default makes you think twice before doing so. And this is in many cases a good thing.

Creating a .p12 file

I'm debugging an issue I'm having with SSL connecting to a database (MySQL RDS) using an ORM called, Prisma. The database connection string requires a PKCS12 (.p12) file (if interested, described here), which brought me here.

I know the question has been answered, but I found the following steps (in Github Issue#2676) to be helpful for creating a .p12 file and wanted to share. Good luck!

  1. Generate 2048-bit RSA private key:

    openssl genrsa -out key.pem 2048

  2. Generate a Certificate Signing Request:

    openssl req -new -sha256 -key key.pem -out csr.csr

  3. Generate a self-signed x509 certificate suitable for use on web servers.

    openssl req -x509 -sha256 -days 365 -key key.pem -in csr.csr -out certificate.pem

  4. Create SSL identity file in PKCS12 as mentioned here

    openssl pkcs12 -export -out client-identity.p12 -inkey key.pem -in certificate.pem

Invalid CSRF Token 'null' was found on the request parameter '_csrf' or header 'X-CSRF-TOKEN'

I used to have the same problem.

Your config use security="none" so cannot generate _csrf:

<http pattern="/login.jsp" security="none"/>

you can set access="IS_AUTHENTICATED_ANONYMOUSLY" for page /login.jsp replace above config:

<http>
    <intercept-url pattern="/login.jsp*" access="IS_AUTHENTICATED_ANONYMOUSLY"/>
    <intercept-url pattern="/**" access="ROLE_USER"/>
    <form-login login-page="/login.jsp"
            authentication-failure-url="/login.jsp?error=1"
            default-target-url="/index.jsp"/>
    <logout/>
    <csrf />
</http>

How does HttpContext.Current.User.Identity.Name know which usernames exist?

Also check that

<modules>
      <remove name="FormsAuthentication"/>
</modules>

If you found anything like this just remove:

<remove name="FormsAuthentication"/>

Line from web.config and here you go it will work fine I have tested it.

Rename multiple columns by names

Building on @user3114046's answer:

x <- data.frame(q=1,w=2,e=3)
x
#  q w e
#1 1 2 3

names(x)[match(oldnames,names(x))] <- newnames

x
#  A w B
#1 1 2 3

This won't be reliant on a specific ordering of columns in the x dataset.

Entity Framework code-first: migration fails with update-database, forces unneccessary(?) add-migration

When using VS2019, MVC5 - look under Migrations folder for file Configuration.cs Edit : AutomaticMigrationsEnabled = true

    -

Laravel: Get Object From Collection By Attribute

Since I don't need to loop entire collection, I think it is better to have helper function like this

/**
 * Check if there is a item in a collection by given key and value
 * @param Illuminate\Support\Collection $collection collection in which search is to be made
 * @param string $key name of key to be checked
 * @param string $value value of key to be checkied
 * @return boolean|object false if not found, object if it is found
 */
function findInCollection(Illuminate\Support\Collection $collection, $key, $value) {
    foreach ($collection as $item) {
        if (isset($item->$key) && $item->$key == $value) {
            return $item;
        }
    }
    return FALSE;
}

Recommended way of making React component/div draggable

I've updated polkovnikov.ph solution to React 16 / ES6 with enhancements like touch handling and snapping to a grid which is what I need for a game. Snapping to a grid alleviates the performance issues.

import React from 'react';
import ReactDOM from 'react-dom';
import PropTypes from 'prop-types';

class Draggable extends React.Component {
    constructor(props) {
        super(props);
        this.state = {
            relX: 0,
            relY: 0,
            x: props.x,
            y: props.y
        };
        this.gridX = props.gridX || 1;
        this.gridY = props.gridY || 1;
        this.onMouseDown = this.onMouseDown.bind(this);
        this.onMouseMove = this.onMouseMove.bind(this);
        this.onMouseUp = this.onMouseUp.bind(this);
        this.onTouchStart = this.onTouchStart.bind(this);
        this.onTouchMove = this.onTouchMove.bind(this);
        this.onTouchEnd = this.onTouchEnd.bind(this);
    }

    static propTypes = {
        onMove: PropTypes.func,
        onStop: PropTypes.func,
        x: PropTypes.number.isRequired,
        y: PropTypes.number.isRequired,
        gridX: PropTypes.number,
        gridY: PropTypes.number
    }; 

    onStart(e) {
        const ref = ReactDOM.findDOMNode(this.handle);
        const body = document.body;
        const box = ref.getBoundingClientRect();
        this.setState({
            relX: e.pageX - (box.left + body.scrollLeft - body.clientLeft),
            relY: e.pageY - (box.top + body.scrollTop - body.clientTop)
        });
    }

    onMove(e) {
        const x = Math.trunc((e.pageX - this.state.relX) / this.gridX) * this.gridX;
        const y = Math.trunc((e.pageY - this.state.relY) / this.gridY) * this.gridY;
        if (x !== this.state.x || y !== this.state.y) {
            this.setState({
                x,
                y
            });
            this.props.onMove && this.props.onMove(this.state.x, this.state.y);
        }        
    }

    onMouseDown(e) {
        if (e.button !== 0) return;
        this.onStart(e);
        document.addEventListener('mousemove', this.onMouseMove);
        document.addEventListener('mouseup', this.onMouseUp);
        e.preventDefault();
    }

    onMouseUp(e) {
        document.removeEventListener('mousemove', this.onMouseMove);
        document.removeEventListener('mouseup', this.onMouseUp);
        this.props.onStop && this.props.onStop(this.state.x, this.state.y);
        e.preventDefault();
    }

    onMouseMove(e) {
        this.onMove(e);
        e.preventDefault();
    }

    onTouchStart(e) {
        this.onStart(e.touches[0]);
        document.addEventListener('touchmove', this.onTouchMove, {passive: false});
        document.addEventListener('touchend', this.onTouchEnd, {passive: false});
        e.preventDefault();
    }

    onTouchMove(e) {
        this.onMove(e.touches[0]);
        e.preventDefault();
    }

    onTouchEnd(e) {
        document.removeEventListener('touchmove', this.onTouchMove);
        document.removeEventListener('touchend', this.onTouchEnd);
        this.props.onStop && this.props.onStop(this.state.x, this.state.y);
        e.preventDefault();
    }

    render() {
        return <div
            onMouseDown={this.onMouseDown}
            onTouchStart={this.onTouchStart}
            style={{
                position: 'absolute',
                left: this.state.x,
                top: this.state.y,
                touchAction: 'none'
            }}
            ref={(div) => { this.handle = div; }}
        >
            {this.props.children}
        </div>;
    }
}

export default Draggable;

jquery - Click event not working for dynamically created button

You could also create the input button in this way:

var button = '<input type="button" id="questionButton" value='+variable+'> <br />';


It might be the syntax of the Button creation that is off somehow.

Execute a command line binary with Node.js

If you don't mind a dependency and want to use promises, child-process-promise works:

installation

npm install child-process-promise --save

exec Usage

var exec = require('child-process-promise').exec;

exec('echo hello')
    .then(function (result) {
        var stdout = result.stdout;
        var stderr = result.stderr;
        console.log('stdout: ', stdout);
        console.log('stderr: ', stderr);
    })
    .catch(function (err) {
        console.error('ERROR: ', err);
    });

spawn usage

var spawn = require('child-process-promise').spawn;

var promise = spawn('echo', ['hello']);

var childProcess = promise.childProcess;

console.log('[spawn] childProcess.pid: ', childProcess.pid);
childProcess.stdout.on('data', function (data) {
    console.log('[spawn] stdout: ', data.toString());
});
childProcess.stderr.on('data', function (data) {
    console.log('[spawn] stderr: ', data.toString());
});

promise.then(function () {
        console.log('[spawn] done!');
    })
    .catch(function (err) {
        console.error('[spawn] ERROR: ', err);
    });

How to call a PHP file from HTML or Javascript

I just want to have a button on my website make a PHP file run

<form action="my.php" method="post">
    <input type="submit">
</form>

Generally speaking, however, unless you are sending new data to the server to be stored, you would just use a link.

<a href="my.php">run php</a>

(Although you should use link text that describes what happens from the user's point of view, not the servers)


I'm making a simple blog site for myself and I've got the code for the site and the javascript that can take the post I write in a textarea and display it immediately. I just want to link it to a PHP file that will create the permanent blog post on the server so that when I reload the page, the post is still there.

This is tricker.

First, you do need to use a form and POST (since you are sending data to be stored).

Then you need to store the data somewhere. This is normally done using a database. Read up on the PDO library for PHP. It is the standard way to interact with databases.

Then you need to pull the data back out again. The simplest approach here is to use the query string to pass the primary key for the database row with the entry you wish to display.

<a href="showBlogEntry.php?entry_id=123">...</a>

Make sure you also read up on SQL injection and XSS.

what is the use of annotations @Id and @GeneratedValue(strategy = GenerationType.IDENTITY)? Why the generationtype is identity?

Simply, @Id: This annotation specifies the primary key of the entity. 

@GeneratedValue: This annotation is used to specify the primary key generation strategy to use. i.e Instructs database to generate a value for this field automatically. If the strategy is not specified by default AUTO will be used. 

GenerationType enum defines four strategies: 
1. Generation Type . TABLE, 
2. Generation Type. SEQUENCE,
3. Generation Type. IDENTITY   
4. Generation Type. AUTO

GenerationType.SEQUENCE

With this strategy, underlying persistence provider must use a database sequence to get the next unique primary key for the entities. 

GenerationType.TABLE

With this strategy, underlying persistence provider must use a database table to generate/keep the next unique primary key for the entities. 

GenerationType.IDENTITY
This GenerationType indicates that the persistence provider must assign primary keys for the entity using a database identity column. IDENTITY column is typically used in SQL Server. This special type column is populated internally by the table itself without using a separate sequence. If underlying database doesn't support IDENTITY column or some similar variant then the persistence provider can choose an alternative appropriate strategy. In this examples we are using H2 database which doesn't support IDENTITY column.

GenerationType.AUTO
This GenerationType indicates that the persistence provider should automatically pick an appropriate strategy for the particular database. This is the default GenerationType, i.e. if we just use @GeneratedValue annotation then this value of GenerationType will be used. 

Reference:- https://www.logicbig.com/tutorials/java-ee-tutorial/jpa/jpa-primary-key.html

JS Client-Side Exif Orientation: Rotate and Mirror JPEG Images

In addition to @fareed namrouti's answer,

This should be used if the image has to be browsed from a file input element

<input type="file" name="file" id="file-input"><br/>
image after transform: <br/>
<div id="container"></div>

<script>
    document.getElementById('file-input').onchange = function (e) {
        var image = e.target.files[0];
        window.loadImage(image, function (img) {
            if (img.type === "error") {
                console.log("couldn't load image:", img);
            } else {
                window.EXIF.getData(image, function () {
                    console.log("load image done!");
                    var orientation = window.EXIF.getTag(this, "Orientation");
                    var canvas = window.loadImage.scale(img,
                        {orientation: orientation || 0, canvas: true, maxWidth: 200});
                    document.getElementById("container").appendChild(canvas);
                    // or using jquery $("#container").append(canvas);
                });
            }
        });
    };
</script>

Python+OpenCV: cv2.imwrite

This following code should extract face in images and save faces on disk

def detect(image):
    image_faces = []
    bitmap = cv.fromarray(image)
    faces = cv.HaarDetectObjects(bitmap, cascade, cv.CreateMemStorage(0))
    if faces:
        for (x,y,w,h),n in faces:
            image_faces.append(image[y:(y+h), x:(x+w)])
            #cv2.rectangle(image,(x,y),(x+w,y+h),(255,255,255),3)
    return image_faces

if __name__ == "__main__":
    cam = cv2.VideoCapture(0)
    while 1:
        _,frame =cam.read()
        image_faces = []
        image_faces = detect(frame)
        for i, face in enumerate(image_faces):
            cv2.imwrite("face-" + str(i) + ".jpg", face)

        #cv2.imshow("features", frame)
        if cv2.waitKey(1) == 0x1b: # ESC
            print 'ESC pressed. Exiting ...'
            break

How can I find out the total physical memory (RAM) of my linux box suitable to be parsed by a shell script?

I find htop a useful tool.

sudo apt-get install htop

and then

free -m

will give the information you need.

PivotTable's Report Filter using "greater than"

In an Excel pivot table, you are correct that a filter only allows values that are explicitly selected. If the filter field is placed on the pivot table rows or columns, however, you get a much wider set of Label Filter conditions, including Greater Than. If you did that in your case, then the added benefit would be that the various probability levels that match your condition are shown in the body of the table.

Python: import module from another directory at the same level in project hierarchy

If I move CreateUser.py to the main user_management directory, I can easily use: import Modules.LDAPManager to import LDAPManager.py --- this works.

Please, don't. In this way the LDAPManager module used by CreateUser will not be the same as the one imported via other imports. This can create problems when you have some global state in the module or during pickling/unpickling. Avoid imports that work only because the module happens to be in the same directory.

When you have a package structure you should either:

  • Use relative imports, i.e if the CreateUser.py is in Scripts/:

     from ..Modules import LDAPManager
    

    Note that this was (note the past tense) discouraged by PEP 8 only because old versions of python didn't support them very well, but this problem was solved years ago. The current version of PEP 8 does suggest them as an acceptable alternative to absolute imports. I actually like them inside packages.

  • Use absolute imports using the whole package name(CreateUser.py in Scripts/):

     from user_management.Modules import LDAPManager
    

In order for the second one to work the package user_management should be installed inside the PYTHONPATH. During development you can configure the IDE so that this happens, without having to manually add calls to sys.path.append anywhere.

Also I find it odd that Scripts/ is a subpackage. Because in a real installation the user_management module would be installed under the site-packages found in the lib/ directory (whichever directory is used to install libraries in your OS), while the scripts should be installed under a bin/ directory (whichever contains executables for your OS).

In fact I believe Script/ shouldn't even be under user_management. It should be at the same level of user_management. In this way you do not have to use -m, but you simply have to make sure the package can be found (this again is a matter of configuring the IDE, installing the package correctly or using PYTHONPATH=. python Scripts/CreateUser.py to launch the scripts with the correct path).


In summary, the hierarchy I would use is:

user_management  (package)
        |
        |------- __init__.py
        |
        |------- Modules/
        |           |
        |           |----- __init__.py
        |           |----- LDAPManager.py
        |           |----- PasswordManager.py
        |

 Scripts/  (*not* a package)
        |  
        |----- CreateUser.py
        |----- FindUser.py

Then the code of CreateUser.py and FindUser.py should use absolute imports to import the modules:

from user_management.Modules import LDAPManager

During installation you make sure that user_management ends up somewhere in the PYTHONPATH, and the scripts inside the directory for executables so that they are able to find the modules. During development you either rely on IDE configuration, or you launch CreateUser.py adding the Scripts/ parent directory to the PYTHONPATH (I mean the directory that contains both user_management and Scripts):

PYTHONPATH=/the/parent/directory python Scripts/CreateUser.py

Or you can modify the PYTHONPATH globally so that you don't have to specify this each time. On unix OSes (linux, Mac OS X etc.) you can modify one of the shell scripts to define the PYTHONPATH external variable, on Windows you have to change the environmental variables settings.


Addendum I believe, if you are using python2, it's better to make sure to avoid implicit relative imports by putting:

from __future__ import absolute_import

at the top of your modules. In this way import X always means to import the toplevel module X and will never try to import the X.py file that's in the same directory (if that directory isn't in the PYTHONPATH). In this way the only way to do a relative import is to use the explicit syntax (the from . import X), which is better (explicit is better than implicit).

This will make sure you never happen to use the "bogus" implicit relative imports, since these would raise an ImportError clearly signalling that something is wrong. Otherwise you could use a module that's not what you think it is.

How to set an iframe src attribute from a variable in AngularJS

It is the $sce service that blocks URLs with external domains, it is a service that provides Strict Contextual Escaping services to AngularJS, to prevent security vulnerabilities such as XSS, clickjacking, etc. it's enabled by default in Angular 1.2.

You can disable it completely, but it's not recommended

angular.module('myAppWithSceDisabledmyApp', [])
   .config(function($sceProvider) {
       $sceProvider.enabled(false);
   });

for more info https://docs.angularjs.org/api/ng/service/$sce

Always pass weak reference of self into block in ARC?

This is how you can use the self inside the block:

//calling of the block

 NSString *returnedText= checkIfOutsideMethodIsCalled(self);

NSString* (^checkIfOutsideMethodIsCalled)(*)=^NSString*(id obj)
{
             [obj MethodNameYouWantToCall]; // this is how it will call the object 
            return @"Called";


};

Nodemailer with Gmail and NodeJS

Easy Solution:

var nodemailer = require('nodemailer');
var smtpTransport = require('nodemailer-smtp-transport');

var transporter = nodemailer.createTransport(smtpTransport({
  service: 'gmail',
  host: 'smtp.gmail.com',
  auth: {
    user: '[email protected]',
    pass: 'realpasswordforaboveaccount'
  }
}));

var mailOptions = {
  from: '[email protected]',
  to: '[email protected]',
  subject: 'Sending Email using Node.js[nodemailer]',
  text: 'That was easy!'
};

transporter.sendMail(mailOptions, function(error, info){
  if (error) {
    console.log(error);
  } else {
    console.log('Email sent: ' + info.response);
  }
});  

Step 1:

go here https://myaccount.google.com/lesssecureapps and enable for less secure apps. If this does not work then

Step 2

go here https://accounts.google.com/DisplayUnlockCaptcha and enable/continue and then try.

for me step 1 alone didn't work so i had to go to step 2.

i also tried removing the nodemailer-smtp-transport package and to my surprise it works. but then when i restarted my system it gave me same error, so i had to go and turn on the less secure app (i disabled it after my work).

then for fun i just tried it with off(less secure app) and vola it worked again!

Attempt to set a non-property-list object as an NSUserDefaults

https://developer.apple.com/reference/foundation/userdefaults

A default object must be a property list—that is, an instance of (or for collections, a combination of instances of): NSData, NSString, NSNumber, NSDate, NSArray, or NSDictionary.

If you want to store any other type of object, you should typically archive it to create an instance of NSData. For more details, see Preferences and Settings Programming Guide.

Console.log not working at all

I feel a bit stupid on this but let this be a lesson to everyone...Make sure you target the right selector!

Basically the console wasn't logging anything because this particular code snippet was attempting to grab the scrolling area of my window, when in fact my code was setup differently to scroll an entire DIV instead. As soon as I changed:

$(window).scroll(function() {

to this:

$('#scroller').scroll(function() {

The console started logging the correct messages.

Unsuccessful append to an empty NumPy array

This error arise from the fact that you are trying to define an object of shape (0,) as an object of shape (2,). If you append what you want without forcing it to be equal to result[0] there is no any issue:

b = np.append([result[0]], [1,2])

But when you define result[0] = b you are equating objects of different shapes, and you can not do this. What are you trying to do?

Multiple markers Google Map API v3 from array of addresses and avoid OVER_QUERY_LIMIT while geocoding on pageLoad

Answer to add multiple markers.

UPDATE (GEOCODE MULTIPLE ADDRESSES)

Here's the working Example Geocoding with multiple addresses.

 <script type="text/javascript" src="http://maps.google.com/maps/api/js?sensor=false">
 </script> 
 <script type="text/javascript">
  var delay = 100;
  var infowindow = new google.maps.InfoWindow();
  var latlng = new google.maps.LatLng(21.0000, 78.0000);
  var mapOptions = {
    zoom: 5,
    center: latlng,
    mapTypeId: google.maps.MapTypeId.ROADMAP
  }
  var geocoder = new google.maps.Geocoder(); 
  var map = new google.maps.Map(document.getElementById("map"), mapOptions);
  var bounds = new google.maps.LatLngBounds();

  function geocodeAddress(address, next) {
    geocoder.geocode({address:address}, function (results,status)
      { 
         if (status == google.maps.GeocoderStatus.OK) {
          var p = results[0].geometry.location;
          var lat=p.lat();
          var lng=p.lng();
          createMarker(address,lat,lng);
        }
        else {
           if (status == google.maps.GeocoderStatus.OVER_QUERY_LIMIT) {
            nextAddress--;
            delay++;
          } else {
                        }   
        }
        next();
      }
    );
  }
 function createMarker(add,lat,lng) {
   var contentString = add;
   var marker = new google.maps.Marker({
     position: new google.maps.LatLng(lat,lng),
     map: map,
           });

  google.maps.event.addListener(marker, 'click', function() {
     infowindow.setContent(contentString); 
     infowindow.open(map,marker);
   });

   bounds.extend(marker.position);

 }
  var locations = [
           'New Delhi, India',
           'Mumbai, India',
           'Bangaluru, Karnataka, India',
           'Hyderabad, Ahemdabad, India',
           'Gurgaon, Haryana, India',
           'Cannaught Place, New Delhi, India',
           'Bandra, Mumbai, India',
           'Nainital, Uttranchal, India',
           'Guwahati, India',
           'West Bengal, India',
           'Jammu, India',
           'Kanyakumari, India',
           'Kerala, India',
           'Himachal Pradesh, India',
           'Shillong, India',
           'Chandigarh, India',
           'Dwarka, New Delhi, India',
           'Pune, India',
           'Indore, India',
           'Orissa, India',
           'Shimla, India',
           'Gujarat, India'
  ];
  var nextAddress = 0;
  function theNext() {
    if (nextAddress < locations.length) {
      setTimeout('geocodeAddress("'+locations[nextAddress]+'",theNext)', delay);
      nextAddress++;
    } else {
      map.fitBounds(bounds);
    }
  }
  theNext();

</script>

As we can resolve this issue with setTimeout() function.

Still we should not geocode known locations every time you load your page as said by @geocodezip

Another alternatives of these are explained very well in the following links:

How To Avoid GoogleMap Geocode Limit!

Geocode Multiple Addresses Tutorial By Mike Williams

Example by Google Developers

From an array of objects, extract value of a property as array

Speaking for the JS only solutions, I've found that, inelegant as it may be, a simple indexed for loop is more performant than its alternatives.

Extracting single property from a 100000 element array (via jsPerf)

Traditional for loop 368 Ops/sec

var vals=[];
for(var i=0;i<testArray.length;i++){
   vals.push(testArray[i].val);
}

ES6 for..of loop 303 Ops/sec

var vals=[];
for(var item of testArray){
   vals.push(item.val); 
}

Array.prototype.map 19 Ops/sec

var vals = testArray.map(function(a) {return a.val;});

TL;DR - .map() is slow, but feel free to use it if you feel readability is worth more than performance.

Edit #2: 6/2019 - jsPerf link broken, removed.

How to open specific tab of bootstrap nav tabs on click of a particuler link using jQuery?

You may access through tab Id as well, But that id is unique for same page. Here is an example for same

$('#product_detail').tab('show');

In above example #product_details is nav tab id

Closing Bootstrap modal onclick

Close the modal with universal $().hide() method:

$('#product-options').hide();

Bootstrap: Open Another Modal in Modal

For bootstrap 4, to expand on @helloroy's answer I used the following;-

var modal_lv = 0 ;
$('body').on('shown.bs.modal', function(e) {
    if ( modal_lv > 0 )
    {
        $('.modal-backdrop:last').css('zIndex',1050+modal_lv) ;
        $(e.target).css('zIndex',1051+modal_lv) ;
    }
    modal_lv++ ;
}).on('hidden.bs.modal', function() {
    if ( modal_lv > 0 )
        modal_lv-- ;
});

The advantage of the above is that it won't have any effect when there is only one modal, it only kicks in for multiples. Secondly, it delegates the handling to the body to ensure future modals which are not currently generated are still catered for.

Update

Moving to a js/css combined solution improves the look - the fade animation continues to work on the backdrop;-

var modal_lv = 0 ;
$('body').on('show.bs.modal', function(e) {
    if ( modal_lv > 0 )
        $(e.target).css('zIndex',1051+modal_lv) ;
    modal_lv++ ;
}).on('hidden.bs.modal', function() {
    if ( modal_lv > 0 )
        modal_lv-- ;
});

combined with the following css;-

.modal-backdrop ~ .modal-backdrop
{
    z-index : 1051 ;
}
.modal-backdrop ~ .modal-backdrop ~ .modal-backdrop
{
    z-index : 1052 ;
}
.modal-backdrop ~ .modal-backdrop ~ .modal-backdrop ~ .modal-backdrop
{
    z-index : 1053 ;
}

This will handle modals nested up to 4 deep which is more than I need.

Waiting on a list of Future

Use a CompletableFuture in Java 8

    // Kick of multiple, asynchronous lookups
    CompletableFuture<User> page1 = gitHubLookupService.findUser("Test1");
    CompletableFuture<User> page2 = gitHubLookupService.findUser("Test2");
    CompletableFuture<User> page3 = gitHubLookupService.findUser("Test3");

    // Wait until they are all done
    CompletableFuture.allOf(page1,page2,page3).join();

    logger.info("--> " + page1.get());

How do I add to the Windows PATH variable using setx? Having weird problems

setx path "%PATH%; C:\Program Files (x86)\Microsoft Office\root\Office16" /m

This should do the appending to the System Environment Variable Path without any extras added, and keeping the original intact without any loss of data. I have used this command to correct the issue that McAfee's Web Control does to Microsoft's Outlook desktop client.

The quotations are used in the path value because command line sees spaces as a delimiter, and will attempt to execute next value in the command line. The quotations override this behavior and handles everything inside the quotations as a string.

How to open a workbook specifying its path

Workbooks.open("E:\sarath\PTMetrics\20131004\D8 L538-L550 16MY\D8 L538-L550_16MY_Powertrain Metrics_20131002.xlsm")

Or, in a more structured way...

Sub openwb()
    Dim sPath As String, sFile As String
    Dim wb As Workbook

    sPath = "E:\sarath\PTMetrics\20131004\D8 L538-L550 16MY\"
    sFile = sPath & "D8 L538-L550_16MY_Powertrain Metrics_20131002.xlsm"

    Set wb = Workbooks.Open(sFile)
End Sub

Stopword removal with NLTK

@alvas has a good answer. But again it depends on the nature of the task, for example in your application you want to consider all conjunction e.g. and, or, but, if, while and all determiner e.g. the, a, some, most, every, no as stop words considering all others parts of speech as legitimate, then you might want to look into this solution which use Part-of-Speech Tagset to discard words, Check table 5.1:

import nltk

STOP_TYPES = ['DET', 'CNJ']

text = "some data here "
tokens = nltk.pos_tag(nltk.word_tokenize(text))
good_words = [w for w, wtype in tokens if wtype not in STOP_TYPES]

Java, How to implement a Shift Cipher (Caesar Cipher)

Two ways to implement a Caesar Cipher:

Option 1: Change chars to ASCII numbers, then you can increase the value, then revert it back to the new character.

Option 2: Use a Map map each letter to a digit like this.

A - 0
B - 1
C - 2
etc...

With a map you don't have to re-calculate the shift every time. Then you can change to and from plaintext to encrypted by following map.

Fastest way to flatten / un-flatten nested JSON objects

Here's mine. It runs in <2ms in Google Apps Script on a sizable object. It uses dashes instead of dots for separators, and it doesn't handle arrays specially like in the asker's question, but this is what I wanted for my use.

function flatten (obj) {
  var newObj = {};
  for (var key in obj) {
    if (typeof obj[key] === 'object' && obj[key] !== null) {
      var temp = flatten(obj[key])
      for (var key2 in temp) {
        newObj[key+"-"+key2] = temp[key2];
      }
    } else {
      newObj[key] = obj[key];
    }
  }
  return newObj;
}

Example:

var test = {
  a: 1,
  b: 2,
  c: {
    c1: 3.1,
    c2: 3.2
  },
  d: 4,
  e: {
    e1: 5.1,
    e2: 5.2,
    e3: {
      e3a: 5.31,
      e3b: 5.32
    },
    e4: 5.4
  },
  f: 6
}

Logger.log("start");
Logger.log(JSON.stringify(flatten(test),null,2));
Logger.log("done");

Example output:

[17-02-08 13:21:05:245 CST] start
[17-02-08 13:21:05:246 CST] {
  "a": 1,
  "b": 2,
  "c-c1": 3.1,
  "c-c2": 3.2,
  "d": 4,
  "e-e1": 5.1,
  "e-e2": 5.2,
  "e-e3-e3a": 5.31,
  "e-e3-e3b": 5.32,
  "e-e4": 5.4,
  "f": 6
}
[17-02-08 13:21:05:247 CST] done

When should an Excel VBA variable be killed or set to Nothing?

VBA uses a garbage collector which is implemented by reference counting.

There can be multiple references to a given object (for example, Dim aw = ActiveWorkbook creates a new reference to Active Workbook), so the garbage collector only cleans up an object when it is clear that there are no other references. Setting to Nothing is an explicit way of decrementing the reference count. The count is implicitly decremented when you exit scope.

Strictly speaking, in modern Excel versions (2010+) setting to Nothing isn't necessary, but there were issues with older versions of Excel (for which the workaround was to explicitly set)

UIScrollView Scrollable Content Size Ambiguity

Xcode 11+, Swift 5.

According to @WantToKnow answer, I solved my issue, I prepared video and code

How to redirect DNS to different ports

Since I had troubles understanding this post here is a simple explanation for people like me. It is useful if:

  • You DO NOT need Load Balacing.
  • You DO NOT want to use nginx to do port forwarding.
  • You DO want to do PORT FORWARDING according to specific subdomains using SRV record.

Then here is what you need to do:

SRV records:

_minecraft._tcp.1.12          IN SRV    1 100 25567 1.12.<your-domain-name.com>.
_minecraft._tcp.1.13          IN SRV    1 100 25566 1.13.<your-domain-name.com>.

(I did not need a srv record for 1.14 since my 1.14 minecraft server was already on the 25565 port which is the default port of minecraft.)

And the A records:

1.12                          IN A      <your server IP>
1.13                          IN A      <your server IP>
1.14                          IN A      <your server IP>

How to get first record in each group using Linq

var res = (from element in list)
      .OrderBy(x => x.F2).AsEnumerable()
      .GroupBy(x => x.F1)
      .Select()

Use .AsEnumerable() after OrderBy()

TypeError: string indices must be integers, not str // working with dict

time1 is the key of the most outer dictionary, eg, feb2012. So then you're trying to index the string, but you can only do this with integers. I think what you wanted was:

for info in courses[time1][course]:

As you're going through each dictionary, you must add another nest.

How to get a index value from foreach loop in jstl

This works for me:

<c:forEach var="i" begin="1970" end="2000">
    <option value="${2000-(i-1970)}">${2000-(i-1970)} 
     </option>
</c:forEach>

Using iFrames In ASP.NET

How about:

<asp:HtmlIframe ID="yourIframe" runat="server" />

Is supported since .Net Framework 4.5

If you have Problems using this control, you might take a look here.

How to git reset --hard a subdirectory?

I'm going to offer a terrible option here, since I have no idea how to do anything with git except add commit and push, here's how I "reverted" a subdirectory:

I started a new repository on my local pc, reverted the whole thing to the commit I wanted to copy code from and then copied those files over to my working directory, add commit push et voila. Don't hate the player, hate Mr Torvalds for being smarter than us all.

Android ViewPager with bottom dots

I thought of posting a simpler solution for the above problem and indicator numbers can be dynamically changed with only changing one variable value dotCounts=x what I did goes like this.

1) Create an xml file in drawable folder for page selected indicator named "item_selected".

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="oval" android:useLevel="true"
    android:dither="true">
    <size android:height="8dp" android:width="8dp"/>
    <solid android:color="@color/image_item_selected_for_dots"/>
</shape>

2) Create one more xml file for unselected indicator named "item_unselected"

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="oval" android:useLevel="true"
    android:dither="true">

    <size android:height="8dp" android:width="8dp"/>

    <solid android:color="@color/image_item_unselected_for_dots"/>
</shape>

3) Now add add this part of the code at the place where you want to display the indicators for ex below viewPager in your Layout XML file.

 <RelativeLayout
        android:id="@+id/viewPagerIndicator"
        android:layout_width="match_parent"
        android:layout_below="@+id/banner_pager"
        android:layout_height="wrap_content"
        android:gravity="center">

        <LinearLayout
            android:id="@+id/viewPagerCountDots"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_centerHorizontal="true"
            android:gravity="center"
            android:orientation="horizontal" />
        </RelativeLayout>

4) Add this function on top of your activity file file where your layout is inflated or the above xml file is related to

private int dotsCount=5;    //No of tabs or images
private ImageView[] dots;
LinearLayout linearLayout;

private void drawPageSelectionIndicators(int mPosition){
    if(linearLayout!=null) {
        linearLayout.removeAllViews();
    }
    linearLayout=(LinearLayout)findViewById(R.id.viewPagerCountDots);
    dots = new ImageView[dotsCount];
    for (int i = 0; i < dotsCount; i++) {
        dots[i] = new ImageView(context);
        if(i==mPosition)
            dots[i].setImageDrawable(getResources().getDrawable(R.drawable.item_selected));
        else
            dots[i].setImageDrawable(getResources().getDrawable(R.drawable.item_unselected));

        LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(
                LinearLayout.LayoutParams.WRAP_CONTENT,
                LinearLayout.LayoutParams.WRAP_CONTENT
        );

        params.setMargins(4, 0, 4, 0);
        linearLayout.addView(dots[i], params);
    }
}

5) Finally in your onCreate method add the following code to reference your layout and handle pageselected positions

drawPageSelectionIndicators(0);
mPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
    @Override
    public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
    }

    @Override
    public void onPageSelected(int position) {
        drawPageSelectionIndicators(position);
    }

    @Override
    public void onPageScrollStateChanged(int state) {
    }
});

How to change title of Activity in Android?

Try setTitle by itself, like this:

setTitle("Hello StackOverflow");

Using Default Arguments in a Function

I would propose changing the function declaration as follows so you can do what you want:

function foo($blah, $x = null, $y = null) {
    if (null === $x) {
        $x = "some value";
    }

    if (null === $y) {
        $y = "some other value";
    }

    code here!

}

This way, you can make a call like foo('blah', null, 'non-default y value'); and have it work as you want, where the second parameter $x still gets its default value.

With this method, passing a null value means you want the default value for one parameter when you want to override the default value for a parameter that comes after it.

As stated in other answers,

default parameters only work as the last arguments to the function. If you want to declare the default values in the function definition, there is no way to omit one parameter and override one following it.

If I have a method that can accept varying numbers of parameters, and parameters of varying types, I often declare the function similar to the answer shown by Ryan P.

Here is another example (this doesn't answer your question, but is hopefully informative:

public function __construct($params = null)
{
    if ($params instanceof SOMETHING) {
        // single parameter, of object type SOMETHING
    } elseif (is_string($params)) {
        // single argument given as string
    } elseif (is_array($params)) {
        // params could be an array of properties like array('x' => 'x1', 'y' => 'y1')
    } elseif (func_num_args() == 3) {
        $args = func_get_args();

        // 3 parameters passed
    } elseif (func_num_args() == 5) {
        $args = func_get_args();
        // 5 parameters passed
    } else {
        throw new \InvalidArgumentException("Could not figure out parameters!");
    }
}

Laravel - Forbidden You don't have permission to access / on this server

It was solved for me with the Laravel default public/.htaccess file adding an extra line:

The /public/.htaccess file remains as follows:

<IfModule mod_rewrite.c>
    <IfModule mod_negotiation.c>
        Options -MultiViews
    </IfModule>

    RewriteEngine On
    DirectoryIndex index.php # This line does the trick

    # Redirect Trailing Slashes If Not A Folder...
    RewriteCond %{REQUEST_FILENAME} !-d
    RewriteRule ^(.*)/$ /$1 [L,R=301]

    # Handle Front Controller...
    RewriteCond %{REQUEST_FILENAME} !-d
    RewriteCond %{REQUEST_FILENAME} !-f
    RewriteRule ^ index.php [L]

    # Handle Authorization Header
    RewriteCond %{HTTP:Authorization} .
    RewriteRule .* - [E=HTTP_AUTHORIZATION:%{HTTP:Authorization}]
</IfModule>

How to verify static void method has been called with power mockito

If you are mocking the behavior (with something like doNothing()) there should really be no need to call to verify*(). That said, here's my stab at re-writing your test method:

@PrepareForTest({InternalUtils.class})
@RunWith(PowerMockRunner.class)
public class InternalServiceTest { //Note the renaming of the test class.
   public void testProcessOrder() {
        //Variables
        InternalService is = new InternalService();
        Order order = mock(Order.class);

        //Mock Behavior
        when(order.isSuccessful()).thenReturn(true);
        mockStatic(Internalutils.class);
        doNothing().when(InternalUtils.class); //This is the preferred way
                                               //to mock static void methods.
        InternalUtils.sendEmail(anyString(), anyString(), anyString(), anyString());

        //Execute
        is.processOrder(order);            

        //Verify
        verifyStatic(InternalUtils.class); //Similar to how you mock static methods
                                           //this is how you verify them.
        InternalUtils.sendEmail(anyString(), anyString(), anyString(), anyString());
   }
}

I grouped into four sections to better highlight what is going on:

1. Variables

I choose to declare any instance variables / method arguments / mock collaborators here. If it is something used in multiple tests, consider making it an instance variable of the test class.

2. Mock Behavior

This is where you define the behavior of all of your mocks. You're setting up return values and expectations here, prior to executing the code under test. Generally speaking, if you set the mock behavior here you wouldn't need to verify the behavior later.

3. Execute

Nothing fancy here; this just kicks off the code being tested. I like to give it its own section to call attention to it.

4. Verify

This is when you call any method starting with verify or assert. After the test is over, you check that the things you wanted to have happen actually did happen. That is the biggest mistake I see with your test method; you attempted to verify the method call before it was ever given a chance to run. Second to that is you never specified which static method you wanted to verify.

Additional Notes

This is mostly personal preference on my part. There is a certain order you need to do things in but within each grouping there is a little wiggle room. This helps me quickly separate out what is happening where.

I also highly recommend going through the examples at the following sites as they are very robust and can help with the majority of the cases you'll need:

Get class list for element with jQuery

I had a similar issue, for an element of type image. I needed to check whether the element was of a certain class. First I tried with:

$('<img>').hasClass("nameOfMyClass"); 

but I got a nice "this function is not available for this element".

Then I inspected my element on the DOM explorer and I saw a very nice attribute that I could use: className. It contained the names of all the classes of my element separated by blank spaces.

$('img').className // it contains "class1 class2 class3"

Once you get this, just split the string as usual.

In my case this worked:

var listOfClassesOfMyElement= $('img').className.split(" ");

I am assuming this would work with other kinds of elements (besides img).

Hope it helps.

Centering controls within a form in .NET (Winforms)?

You could achieve this with the use of anchors. Or more precisely the non use of them.

Controls are anchored by default to the top left of the form which means when the form size will be changed, their distance from the top left side of the form will remain constant. If you change the control anchor to bottom left, then the control will keep the same distance from the bottom and left sides of the form when the form if resized.

Turning off the anchor in a direction will keep the control centered in that direction when resizing.

NOTE: Turning off anchoring via the properties window in VS2015 may require entering None, None (instead of default Top,Left)

$(document).ready equivalent without jQuery

Nowadays you should use modules. Put your code into the default function of a module and import the function into a script element.

client.js:

export default function ()
{
  alert ("test");
}

index.html:

<!DOCTYPE html>
<html>
  <head>
    <meta charset="UTF-8">
    <title>test</title>
  </head>
  <body>
    <script type="module">
      import main from './client.js';
      main ();
    </script>
  </body>
</html>

Why am I getting InputMismatchException?

Since you have the manual user input loop, after the scanner has read your first input it will pass the carriage/return into the next line which will also be read; of course, that is not what you wanted.

You can try this

try {
    // ...
} catch (InputMismatchException e) {
    reader.next(); 
}

or alternatively, you can consume that carriage return before reading your next double input by calling

reader.next()

Bootstrap 3 Flush footer to bottom. not fixed

This method uses minimal markup. Just put all your content in a .wrapper which has a padding-bottom and negative margin-bottom equal to the footer height (in my example 100px).

html, body {
    height: 100%;
}

/* give the wrapper a padding-bottom and negative margin-bottom equal to the footer height */

.wrapper {
    min-height: 100%;
    height: auto;
    margin: 0 auto -100px;
    padding-bottom: 100px;
}
.footer {
    height: 100px;
}

<body>

<div class="wrapper">
  <p>Your website content here.</p>
</div>
<div class="footer">
   <p>Copyright (c) 2014</p>
</div>

</body>

"Port 4200 is already in use" when running the ng serve command

In Windows; In command prompt which is running your ng serve just click and press keys:

ctrl + c

It will ask you: Terminate batch job (Y/N)? and you type Y

Is there a git-merge --dry-run option?

This might be interesting: From the documentation:

If you tried a merge which resulted in complex conflicts and want to start over, you can recover with git merge --abort.

But you could also do it the naive (but slow) way:

rm -Rf /tmp/repository
cp -r repository /tmp/
cd /tmp/repository
git merge ...
...if successful, do the real merge. :)

(Note: It won't work just cloning to /tmp, you'd need a copy, in order to be sure that uncommitted changes will not conflict).

How to pass a URI to an intent?

If you want to use standard extra data field, you would do something like this:

private Uri imageUri;
....
Intent intent = new Intent(this, GoogleActivity.class);
intent.putExtra(Intent.EXTRA_STREAM, imageUri.toString());
startActivity(intent);
this.finish();

The documentation for Intent says:

EXTRA_STREAM   added in API level 1 
String EXTRA_STREAM
A content: URI holding a stream of data associated with the Intent,
used with ACTION_SEND to supply the data being sent. 

Constant Value: "android.intent.extra.STREAM"

You don't have to use the built-in standard names, but it's probably good practice and more reusable. Take a look at the developer documentation for a list of all the built-in standard extra data fields.

Querying Windows Active Directory server using ldapsearch from command line

You could query an LDAP server from the command line with ldap-utils: ldapsearch, ldapadd, ldapmodify

HTML set image on browser tab

It's called a Favicon, have a read.

<link rel="shortcut icon" href="http://www.example.com/myicon.ico"/>

You can use this neat tool to generate cross-browser compatible Favicons.

Jenkins: Is there any way to cleanup Jenkins workspace?

not allowed to comment, therefore:

The answer from Upen works just fine, but not if you have Jenkins Pipeline Jobs mixed with Freestyle Jobs. There is no such Method as DoWipeWorkspace on Pipeline Jobs. So I modified the Script in order to skip those:

import hudson.model.*
import org.jenkinsci.plugins.workflow.job.WorkflowJob

// For each project
for(item in Hudson.instance.items) {
  // check that job is not building
  if(!item.isBuilding() && !(item instanceof WorkflowJob))
  {
    println("Wiping out workspace of job "+item.name)
    item.doDoWipeOutWorkspace()
  }
  else {
    println("Skipping job "+item.name+", currently building")
  }
}

you could also filter by Job Names if required: item.getDisplayName().toLowerCase().contains("release")

What's the easiest way to escape HTML in Python?

Not the easiest way, but still straightforward. The main difference from cgi.escape module - it still will work properly if you already have &amp; in your text. As you see from comments to it:

cgi.escape version

def escape(s, quote=None):
    '''Replace special characters "&", "<" and ">" to HTML-safe sequences.
    If the optional flag quote is true, the quotation mark character (")
is also translated.'''
    s = s.replace("&", "&amp;") # Must be done first!
    s = s.replace("<", "&lt;")
    s = s.replace(">", "&gt;")
    if quote:
        s = s.replace('"', "&quot;")
    return s

regex version

QUOTE_PATTERN = r"""([&<>"'])(?!(amp|lt|gt|quot|#39);)"""
def escape(word):
    """
    Replaces special characters <>&"' to HTML-safe sequences. 
    With attention to already escaped characters.
    """
    replace_with = {
        '<': '&gt;',
        '>': '&lt;',
        '&': '&amp;',
        '"': '&quot;', # should be escaped in attributes
        "'": '&#39'    # should be escaped in attributes
    }
    quote_pattern = re.compile(QUOTE_PATTERN)
    return re.sub(quote_pattern, lambda x: replace_with[x.group(0)], word)

java.lang.ClassNotFoundException: org.springframework.boot.SpringApplication Maven

The answer to the above question is "none of the above". When you download new STS it won't support the old Spring Boot parent version. Just update parent version with latest comes with STS it will work.

<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>1.5.8.RELEASE</version>
    <relativePath/> <!-- lookup parent from repository -->
</parent>

If you have problem getting the latest, just create a new Spring Starter Project. Go to File->New->Spring Start Project and create a demo project you will get the latest parent version, change your version with that all will work. I do this every time I change STS.

How to run Java program in terminal with external library JAR

For compiling the java file having dependency on a jar

javac -cp path_of_the_jar/jarName.jar className.java

For executing the class file

java -cp .;path_of_the_jar/jarName.jar className

Casting variables in Java

Actually, casting doesn't always work. If the object is not an instanceof the class you're casting it to you will get a ClassCastException at runtime.

Copy a file in a sane, safe and efficient way

I want to make the very important note that the LINUX method using sendfile() has a major problem in that it can not copy files more than 2GB in size! I had implemented it following this question and was hitting problems because I was using it to copy HDF5 files that were many GB in size.

http://man7.org/linux/man-pages/man2/sendfile.2.html

sendfile() will transfer at most 0x7ffff000 (2,147,479,552) bytes, returning the number of bytes actually transferred. (This is true on both 32-bit and 64-bit systems.)

How to convert float to int with Java

Using Math.round() will round the float to the nearest integer.

Are SSL certificates bound to the servers ip address?

SSL certificates are bound to a 'common name', which is usually a fully qualified domain name but can be a wildcard name (eg. *.domain.com) or even an IP address, but it usually isn't.

In your case, you are accessing your LDAP server by a hostname and it sounds like your two LDAP servers have different SSL certificates installed. Are you able to view (or download and view) the details of the SSL certificate? Each SSL certificate will have a unique serial numbers and fingerprint which will need to match. I assume the certificate is being rejected as these details don't match with what's in your certificate store.

Your solution will be to ensure that both LDAP servers have the same SSL certificate installed.

BTW - you can normally override DNS entries on your workstation by editing a local 'hosts' file, but I wouldn't recommend this.

How to style a div to have a background color for the entire width of the content, and not just for the width of the display?

.success { background-color: #cffccc; overflow: scroll; min-width: 100%; }

You can try scroll or auto.

Error: Cannot find module html

I think you might need to declare a view engine.

If you want to use a view/template engine:

app.set('view engine', 'ejs');

or

app.set('view engine', 'jade');

But to render plain-html, see this post: Render basic HTML view?.

How do I update/upsert a document in Mongoose?

No other solution worked for me. I'm using a post request and updating data if found else insert it, also _id is sent with the request body that's needs to be removed.

router.post('/user/createOrUpdate', function(req,res){
    var request_data = req.body;
    var userModel = new User(request_data);
    var upsertData = userModel.toObject();
    delete upsertData._id;

    var currentUserId;
    if (request_data._id || request_data._id !== '') {
        currentUserId = new mongoose.mongo.ObjectId(request_data._id);
    } else {
        currentUserId = new mongoose.mongo.ObjectId();
    }

    User.update({_id: currentUserId}, upsertData, {upsert: true},
        function (err) {
            if (err) throw err;
        }
    );
    res.redirect('/home');

});

jQuery - Uncaught RangeError: Maximum call stack size exceeded

Your calls are made recursively which pushes functions on to the stack infinitely that causes max call stack exceeded error due to recursive behavior. Instead try using setTimeout which is a callback.

Also based on your markup your selector is wrong. it should be #advisersDiv

Demo

function fadeIn() {
    $('#pulseDiv').find('div#advisersDiv').delay(400).addClass("pulse");
    setTimeout(fadeOut,1); //<-- Provide any delay here
};

function fadeOut() {
    $('#pulseDiv').find('div#advisersDiv').delay(400).removeClass("pulse");
    setTimeout(fadeIn,1);//<-- Provide any delay here
};
fadeIn();

Is there a way to remove the separator line from a UITableView?

In your viewDidLoad:

self.tableView.tableFooterView = [[UIView alloc] initWithFrame:CGRectZero];
if ([self.tableView respondsToSelector:@selector(setSeparatorInset:)])
{
    [self.tableView setSeparatorInset:UIEdgeInsetsZero];
}

Refresh image with a new one at the same url

<img src='someurl.com/someimage.ext' onload='imageRefresh(this, 1000);'>

Then below in some javascript

<script language='javascript'>
 function imageRefresh(img, timeout) {
    setTimeout(function() {
     var d = new Date;
     var http = img.src;
     if (http.indexOf("&d=") != -1) { http = http.split("&d=")[0]; } 

     img.src = http + '&d=' + d.getTime();
    }, timeout);
  }
</script>

And so what this does is, when the image loads, schedules it to be reloaded in 1 second. I'm using this on a page with home security cameras of varying type.

How do you create optional arguments in php?

The date function would be defined something like this:

function date($format, $timestamp = null)
{
    if ($timestamp === null) {
        $timestamp = time();
    }

    // Format the timestamp according to $format
}

Usually, you would put the default value like this:

function foo($required, $optional = 42)
{
    // This function can be passed one or more arguments
}

However, only literals are valid default arguments, which is why I used null as default argument in the first example, not $timestamp = time(), and combined it with a null check. Literals include arrays (array() or []), booleans, numbers, strings, and null.

Usage of @see in JavaDoc?

@see is useful for information about related methods/classes in an API. It will produce a link to the referenced method/code on the documentation. Use it when there is related code that might help the user understand how to use the API.

Preventing an image from being draggable or selectable without using JS

Set the following CSS properties to the image:

user-drag: none; 
user-select: none;
-moz-user-select: none;
-webkit-user-drag: none;
-webkit-user-select: none;
-ms-user-select: none;

How return error message in spring mvc @Controller

Here is an alternative. Create a generic exception that takes a status code and a message. Then create an exception handler. Use the exception handler to retrieve the information out of the exception and return to the caller of the service.

http://javaninja.net/2016/06/throwing-exceptions-messages-spring-mvc-controller/

public class ResourceException extends RuntimeException {

    private HttpStatus httpStatus = HttpStatus.INTERNAL_SERVER_ERROR;

    public HttpStatus getHttpStatus() {
        return httpStatus;
    }

    /**
     * Constructs a new runtime exception with the specified detail message.
     * The cause is not initialized, and may subsequently be initialized by a
     * call to {@link #initCause}.
     * @param message the detail message. The detail message is saved for later retrieval by the {@link #getMessage()}
     *                method.
     */
    public ResourceException(HttpStatus httpStatus, String message) {
        super(message);
        this.httpStatus = httpStatus;
    }
}

Then use an exception handler to retrieve the information and return it to the service caller.

@ControllerAdvice
public class ExceptionHandlerAdvice { 

    @ExceptionHandler(ResourceException.class)
    public ResponseEntity handleException(ResourceException e) {
        // log exception 
        return ResponseEntity.status(e.getHttpStatus()).body(e.getMessage());
    }         
} 

Then create an exception when you need to.

throw new ResourceException(HttpStatus.NOT_FOUND, "We were unable to find the specified resource.");

keycode and charcode

The property event.which is added when using jQuery to avoid browser differences. See docs.

The which property will be undefined if you are not using jQuery.

Java rounding up to an int using Math.ceil

157/32 is int/int, which results in an int.

Try using the double literal - 157/32d, which is int/double, which results in a double.

Get value of a specific object property in C# without knowing the class behind

Reflection can help you.

var someObject;
var propertyName = "PropertyWhichValueYouWantToKnow";
var propertyName = someObject.GetType().GetProperty(propertyName).GetValue(someObject, null);

How to draw a custom UIView that is just a circle - iPhone app

Swift 3 - Xcode 8.1

@IBOutlet weak var myView: UIView!

override func viewDidLoad() {
    super.viewDidLoad() 

    let size:CGFloat = 35.0
    myView.bounds = CGRect(x: 0, y: 0, width: size, height: size)
    myView.layer.cornerRadius = size / 2
    myView.layer.borderWidth = 1
    myView.layer.borderColor = UIColor.Gray.cgColor        
}

Python Remove last char from string and return it

Strings are "immutable" for good reason: It really saves a lot of headaches, more often than you'd think. It also allows python to be very smart about optimizing their use. If you want to process your string in increments, you can pull out part of it with split() or separate it into two parts using indices:

a = "abc"
a, result = a[:-1], a[-1]

This shows that you're splitting your string in two. If you'll be examining every byte of the string, you can iterate over it (in reverse, if you wish):

for result in reversed(a):
    ...

I should add this seems a little contrived: Your string is more likely to have some separator, and then you'll use split:

ans = "foo,blah,etc."
for a in ans.split(","):
    ...

How to $watch multiple variable change in angular

$scope.$watch('age + name', function () {
  //called when name or age changed
});

How do I initialize the base (super) class?

Both

SuperClass.__init__(self, x)

or

super(SubClass,self).__init__( x )

will work (I prefer the 2nd one, as it adheres more to the DRY principle).

See here: http://docs.python.org/reference/datamodel.html#basic-customization

Why do we check up to the square root of a prime number to determine if it is prime?

A more intuitive explanation would be :-

The square root of 100 is 10. Let's say a x b = 100, for various pairs of a and b.

If a == b, then they are equal, and are the square root of 100, exactly. Which is 10.

If one of them is less than 10, the other has to be greater. For example, 5 x 20 == 100. One is greater than 10, the other is less than 10.

Thinking about a x b, if one of them goes down, the other must get bigger to compensate, so the product stays at 100. They pivot around the square root.

The square root of 101 is about 10.049875621. So if you're testing the number 101 for primality, you only need to try the integers up through 10, including 10. But 8, 9, and 10 are not themselves prime, so you only have to test up through 7, which is prime.

Because if there's a pair of factors with one of the numbers bigger than 10, the other of the pair has to be less than 10. If the smaller one doesn't exist, there is no matching larger factor of 101.

If you're testing 121, the square root is 11. You have to test the prime integers 1 through 11 (inclusive) to see if it goes in evenly. 11 goes in 11 times, so 121 is not prime. If you had stopped at 10, and not tested 11, you would have missed 11.

You have to test every prime integer greater than 2, but less than or equal to the square root, assuming you are only testing odd numbers.

`

How do I show my global Git configuration?

Since Git 2.26.0, you can use --show-scope option:

git config --list --show-scope

Example output:

system  rebase.autosquash=true
system  credential.helper=helper-selector
global  core.editor='code.cmd' --wait -n
global  merge.tool=kdiff3
local   core.symlinks=false
local   core.ignorecase=true

It can be combined with

  • --local for project config, --global for user config, --system for all users' config
  • --show-origin to show the exact config file location

Converting NumPy array into Python List structure?

Use tolist():

import numpy as np
>>> np.array([[1,2,3],[4,5,6]]).tolist()
[[1, 2, 3], [4, 5, 6]]

Note that this converts the values from whatever numpy type they may have (e.g. np.int32 or np.float32) to the "nearest compatible Python type" (in a list). If you want to preserve the numpy data types, you could call list() on your array instead, and you'll end up with a list of numpy scalars. (Thanks to Mr_and_Mrs_D for pointing that out in a comment.)

Is key-value pair available in Typescript?

TypeScript has Map. You can use like:

public myMap = new Map<K,V>([
[k1, v1],
[k2, v2]
]);

myMap.get(key); // returns value
myMap.set(key, value); // import a new data
myMap.has(key); // check data

Navigate to another page with a button in angular 2

Having the router link on the button seems to work fine for me:

<button class="nav-link" routerLink="/" (click)="hideMenu()">
     <i class="fa fa-home"></i> 
     <span>Home</span>
</button>

Does a finally block always get executed in Java?

Also, although it's bad practice, if there is a return statement within the finally block, it will trump any other return from the regular block. That is, the following block would return false:

try { return true; } finally { return false; }

Same thing with throwing exceptions from the finally block.

Docker Repository Does Not Have a Release File on Running apt-get update on Ubuntu

I also had a similar issue. Someone might find what worked for me helpful.

Machine is running Ubuntu 16.04 and has Docker CE. After looking through the answers and links provided here, especially from the link from the Docker website given by Elliot Beach, I opened my /etc/apt/sources.list and examined it.

The file had both deb [arch=amd64] https://download.docker.com/linux/ubuntu (lsb_release -cs) stable and deb [arch=amd64] https://download.docker.com/linux/ubuntu xenial stable.

Since the second one was what was needed, I simply commented out the first, saved the document and now the issue is fixed. As a test, I went back into the same document, removed the comment sign and ran sudo apt-get update again. The issue returned when I did that.

So to recap : not only did I have my parent Ubuntu distribution name as stated on the Docker website but I also commented out the line still containing (lsb_release -cs).

How to make connection to Postgres via Node.js

One solution can be using pool of clients like the following:

const { Pool } = require('pg');
var config = {
    user: 'foo', 
    database: 'my_db', 
    password: 'secret', 
    host: 'localhost', 
    port: 5432, 
    max: 10, // max number of clients in the pool
    idleTimeoutMillis: 30000
};
const pool = new Pool(config);
pool.on('error', function (err, client) {
    console.error('idle client error', err.message, err.stack);
});
pool.query('SELECT $1::int AS number', ['2'], function(err, res) {
    if(err) {
        return console.error('error running query', err);
    }
    console.log('number:', res.rows[0].number);
});

You can see more details on this resource.

Javascript, Change google map marker color

To expand upon the accepted answer, you can create custom MarkerImages of any color using the API at http://chart.googleapis.com

In addition to changing color, this also changes marker shape, which may be unwanted.

const marker = new window.google.maps.Marker(
        position: markerPosition,
        title: markerTitle,
        map: map)
marker.addListener('click', () => marker.setIcon(changeIcon('00ff00'));)

const changeIcon = (newIconColor) => {
    const newIcon = new window.google.maps.MarkerImage(
        `http://chart.googleapis.com/chart?                                      
        chst=d_map_spin&chld=1.0|0|${newIconColor}|60|_|%E2%80%A2`,
        new window.google.maps.Size(21, 34),
        new window.google.maps.Point(0, 0),
        new window.google.maps.Point(10, 34),
        new window.google.maps.Size(21,34)
    );
    return newIcon
}

Source: free udacity course on google maps apis

How to get summary statistics by group

The psych package has a great option for grouped summary stats:

library(psych)
    
describeBy(dt, group="grp")

produces lots of useful stats including mean, median, range, sd, se.

What is the benefit of zerofill in MySQL?

I know I'm late to the party but I find the zerofill is helpful for boolean representations of TINYINT(1). Null doesn't always mean False, sometimes you don't want it to. By zerofilling a tinyint, you're effectively converting those values to INT and removing any confusion ur application may have upon interaction. Your application can then treat those values in a manner similar to the primitive datatype True = Not(0)

Comparing strings by their alphabetical order

You can call either string's compareTo method (java.lang.String.compareTo). This feature is well documented on the java documentation site.

Here is a short program that demonstrates it:

class StringCompareExample {
    public static void main(String args[]){
        String s1 = "Project"; String s2 = "Sunject";
        verboseCompare(s1, s2);
        verboseCompare(s2, s1);
        verboseCompare(s1, s1);
    }

    public static void verboseCompare(String s1, String s2){
        System.out.println("Comparing \"" + s1 + "\" to \"" + s2 + "\"...");

        int comparisonResult = s1.compareTo(s2);
        System.out.println("The result of the comparison was " + comparisonResult);

        System.out.print("This means that \"" + s1 + "\" ");
        if(comparisonResult < 0){
            System.out.println("lexicographically precedes \"" + s2 + "\".");
        }else if(comparisonResult > 0){
            System.out.println("lexicographically follows \"" + s2 + "\".");
        }else{
            System.out.println("equals \"" + s2 + "\".");
        }
        System.out.println();
    }
}

Here is a live demonstration that shows it works: http://ideone.com/Drikp3

How to Multi-thread an Operation Within a Loop in Python

import numpy as np
import threading


def threaded_process(items_chunk):
    """ Your main process which runs in thread for each chunk"""
    for item in items_chunk:                                               
        try:                                                                    
            api.my_operation(item)                                              
        except Exception:                                                       
            print('error with item')  

n_threads = 20
# Splitting the items into chunks equal to number of threads
array_chunk = np.array_split(input_image_list, n_threads)
thread_list = []
for thr in range(n_threads):
    thread = threading.Thread(target=threaded_process, args=(array_chunk[thr]),)
    thread_list.append(thread)
    thread_list[thr].start()

for thread in thread_list:
    thread.join()

Scrolling a flexbox with overflowing content

The solution for this problem is just to add overflow: auto; to the .content for making the content wrapper scrollable.

Furthermore, there are circumstances occurring along with Flexbox wrapper and overflowed scrollable content like this codepen.

The solution is to add overflow: hidden (or auto); to the parent of the wrapper (set with overflow: auto;) around large contents.

Is Ruby pass by reference or by value?

Parameters are a copy of the original reference. So, you can change values, but cannot change the original reference.

How do I change the background of a Frame in Tkinter?

You use ttk.Frame, bg option does not work for it. You should create style and apply it to the frame.

from tkinter import *
from tkinter.ttk import * 

root = Tk()

s = Style()
s.configure('My.TFrame', background='red')

mail1 = Frame(root, style='My.TFrame')
mail1.place(height=70, width=400, x=83, y=109)
mail1.config()
root.mainloop()

Selenium: Can I set any of the attribute value of a WebElement in Selenium?

Fancy C# extension method based on previous answers:

public static IWebElement SetAttribute(this IWebElement element, string name, string value)
{
    var driver = ((IWrapsDriver)element).WrappedDriver;
    var jsExecutor = (IJavaScriptExecutor)driver;
    jsExecutor.ExecuteScript("arguments[0].setAttribute(arguments[1], arguments[2]);", element, name, value);

    return element;
}

Usage:

driver.FindElement(By.Id("some_option")).SetAttribute("selected", "selected");

How to simulate a real mouse click using java?

You could create a simple AutoIt Script that does the job for you, compile it as an executable and perform a system call there.

in au3 Script:

; how to use: MouseClick ( "button" [, x, y [, clicks = 1 [, speed = 10]]] )
MouseClick ( "left" , $CmdLine[1], $CmdLine[1] )

Now find aut2exe in your au3 Folder or find 'Compile Script to .exe' in your Start Menu and create an executable.

in your Java class call:

Runtime.getRuntime().exec(
    new String[]{
        "yourscript.exe", 
        String.valueOf(mypoint.x),
        String.valueOf(mypoint.y)}
);

AutoIt will behave as if it was a human and won't be detected as a machine.

Find AutoIt here: https://www.autoitscript.com/

How to set combobox default value?

Suppose you bound your combobox to a List<Person>

List<Person> pp = new List<Person>();
pp.Add(new Person() {id = 1, name="Steve"});
pp.Add(new Person() {id = 2, name="Mark"});
pp.Add(new Person() {id = 3, name="Charles"});

cbo1.DisplayMember = "name";
cbo1.ValueMember = "id";
cbo1.DataSource = pp;

At this point you cannot set the Text property as you like, but instead you need to add an item to your list before setting the datasource

pp.Insert(0, new Person() {id=-1, name="--SELECT--"});
cbo1.DisplayMember = "name";
cbo1.ValueMember = "id";
cbo1.DataSource = pp;
cbo1.SelectedIndex = 0;

Of course this means that you need to add a checking code when you try to use the info from the combobox

if(cbo1.SelectedValue != null && Convert.ToInt32(cbo1.SelectedValue) == -1)
    MessageBox.Show("Please select a person name");
else
    ...... 

The code is the same if you use a DataTable instead of a list. You need to add a fake row at the first position of the Rows collection of the datatable and set the initial index of the combobox to make things clear. The only thing you need to look at are the name of the datatable columns and which columns should contain a non null value before adding the row to the collection

In a table with three columns like ID, FirstName, LastName with ID,FirstName and LastName required you need to

DataRow row = datatable.NewRow();
row["ID"] = -1;
row["FirstName"] = "--Select--";    
row["LastName"] = "FakeAddress";
dataTable.Rows.InsertAt(row, 0);

Pass props in Link react-router

This line is missing path:

<Route name="ideas" handler={CreateIdeaView} />

Should be:

<Route name="ideas" path="/:testvalue" handler={CreateIdeaView} />

Given the following Link (outdated v1):

<Link to="ideas" params={{ testvalue: "hello" }}>Create Idea</Link>

Up to date as of v4:

const backUrl = '/some/other/value'
// this.props.testvalue === "hello"
<Link to={{pathname: `/${this.props.testvalue}`, query: {backUrl}}} />

and in the withRouter(CreateIdeaView) components render():

console.log(this.props.match.params.testvalue, this.props.location.query.backurl)
// output
hello /some/other/value

From the link that you posted on the docs, towards the bottom of the page:

Given a route like <Route name="user" path="/users/:userId"/>



Updated code example with some stubbed query examples:

_x000D_
_x000D_
// import React, {Component, Props, ReactDOM} from 'react';_x000D_
// import {Route, Switch} from 'react-router'; etc etc_x000D_
// this snippet has it all attached to window since its in browser_x000D_
const {_x000D_
  BrowserRouter,_x000D_
  Switch,_x000D_
  Route,_x000D_
  Link,_x000D_
  NavLink_x000D_
} = ReactRouterDOM;_x000D_
_x000D_
class World extends React.Component {_x000D_
  constructor(props) {_x000D_
    super(props);_x000D_
    console.dir(props);      _x000D_
    this.state = {_x000D_
      fromIdeas: props.match.params.WORLD || 'unknown'_x000D_
    }_x000D_
  }_x000D_
  render() {_x000D_
    const { match, location} = this.props;_x000D_
    return (_x000D_
      <React.Fragment>_x000D_
        <h2>{this.state.fromIdeas}</h2>_x000D_
        <span>thing: _x000D_
          {location.query _x000D_
            && location.query.thing}_x000D_
        </span><br/>_x000D_
        <span>another1: _x000D_
        {location.query _x000D_
          && location.query.another1 _x000D_
          || 'none for 2 or 3'}_x000D_
        </span>_x000D_
      </React.Fragment>_x000D_
    );_x000D_
  }_x000D_
}_x000D_
_x000D_
class Ideas extends React.Component {_x000D_
  constructor(props) {_x000D_
    super(props);_x000D_
    console.dir(props);_x000D_
    this.state = {_x000D_
      fromAppItem: props.location.item,_x000D_
      fromAppId: props.location.id,_x000D_
      nextPage: 'world1',_x000D_
      showWorld2: false_x000D_
    }_x000D_
  }_x000D_
  render() {_x000D_
    return (_x000D_
      <React.Fragment>_x000D_
          <li>item: {this.state.fromAppItem.okay}</li>_x000D_
          <li>id: {this.state.fromAppId}</li>_x000D_
          <li>_x000D_
            <Link _x000D_
              to={{_x000D_
                pathname: `/hello/${this.state.nextPage}`, _x000D_
                query:{thing: 'asdf', another1: 'stuff'}_x000D_
              }}>_x000D_
              Home 1_x000D_
            </Link>_x000D_
          </li>_x000D_
          <li>_x000D_
            <button _x000D_
              onClick={() => this.setState({_x000D_
              nextPage: 'world2',_x000D_
              showWorld2: true})}>_x000D_
              switch  2_x000D_
            </button>_x000D_
          </li>_x000D_
          {this.state.showWorld2 _x000D_
           && _x000D_
           <li>_x000D_
              <Link _x000D_
                to={{_x000D_
                  pathname: `/hello/${this.state.nextPage}`, _x000D_
                  query:{thing: 'fdsa'}}} >_x000D_
                Home 2_x000D_
              </Link>_x000D_
            </li> _x000D_
          }_x000D_
        <NavLink to="/hello">Home 3</NavLink>_x000D_
      </React.Fragment>_x000D_
    );_x000D_
  }_x000D_
}_x000D_
_x000D_
_x000D_
class App extends React.Component {_x000D_
  render() {_x000D_
    return (_x000D_
      <React.Fragment>_x000D_
        <Link to={{_x000D_
          pathname:'/ideas/:id', _x000D_
          id: 222, _x000D_
          item: {_x000D_
              okay: 123_x000D_
          }}}>Ideas</Link>_x000D_
        <Switch>_x000D_
          <Route exact path='/ideas/:id/' component={Ideas}/>_x000D_
          <Route path='/hello/:WORLD?/:thing?' component={World}/>_x000D_
        </Switch>_x000D_
      </React.Fragment>_x000D_
    );_x000D_
  }_x000D_
}_x000D_
_x000D_
ReactDOM.render((_x000D_
  <BrowserRouter>_x000D_
    <App />_x000D_
  </BrowserRouter>_x000D_
), document.getElementById('ideas'));
_x000D_
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/16.6.3/umd/react.production.min.js"></script>_x000D_
<script src="https://cdnjs.cloudflare.com/ajax/libs/react-dom/16.6.3/umd/react-dom.production.min.js"></script>_x000D_
<script src="https://cdnjs.cloudflare.com/ajax/libs/react-router-dom/4.3.1/react-router-dom.min.js"></script>_x000D_
<script src="https://cdnjs.cloudflare.com/ajax/libs/react-router/4.3.1/react-router.min.js"></script>_x000D_
_x000D_
<div id="ideas"></div>
_x000D_
_x000D_
_x000D_

updates:

See: https://github.com/ReactTraining/react-router/blob/0c6d51cd6639aff8a84b11d89e27887b3558ed8a/upgrade-guides/v2.0.0.md#link-to-onenter-and-isactive-use-location-descriptors

From the upgrade guide from 1.x to 2.x:

<Link to>, onEnter, and isActive use location descriptors

<Link to> can now take a location descriptor in addition to strings. The query and state props are deprecated.

// v1.0.x

<Link to="/foo" query={{ the: 'query' }}/>

// v2.0.0

<Link to={{ pathname: '/foo', query: { the: 'query' } }}/>

// Still valid in 2.x

<Link to="/foo"/>

Likewise, redirecting from an onEnter hook now also uses a location descriptor.

// v1.0.x

(nextState, replaceState) => replaceState(null, '/foo')
(nextState, replaceState) => replaceState(null, '/foo', { the: 'query' })

// v2.0.0

(nextState, replace) => replace('/foo')
(nextState, replace) => replace({ pathname: '/foo', query: { the: 'query' } })

For custom link-like components, the same applies for router.isActive, previously history.isActive.

// v1.0.x

history.isActive(pathname, query, indexOnly)

// v2.0.0

router.isActive({ pathname, query }, indexOnly)

updates for v3 to v4:

"legacy migration documentation" for posterity

How do I do a not equal in Django queryset filtering?

results = Model.objects.filter(a = True).exclude(x = 5)
Generetes this sql:
select * from tablex where a != 0 and x !=5
The sql depends on how your True/False field is represented, and the database engine. The django code is all you need though.

Disable beep of Linux Bash on Windows 10

Replace in System Sounds the "Critical Stop" to a wav-file which is silent 1.

Just removing the sound completely did not work for me. Apparently some default sound was used in this case.

System sounds configuration

(Credits for this.lau_ on SuperUser for discovering this).

Angularjs error Unknown provider

bmleite has the correct answer about including the module.

If that is correct in your situation, you should also ensure that you are not redefining the modules in multiple files.

Remember:

angular.module('ModuleName', [])   // creates a module.

angular.module('ModuleName')       // gets you a pre-existing module.

So if you are extending a existing module, remember not to overwrite when trying to fetch it.

git pull error :error: remote ref is at but expected

I had to remove my branch from my command line at:

.git\refs\remotes\{my remote}\{**my branch**}

and then manually doing:

git pull [remote_name] [branch_name]

I was able to pull the changes.

Note: I was using SourceTree and was unable to do the pull.

Vector of Vectors to create matrix

I'm not familiar with c++, but a quick look at the documentation suggests that this should work:

//cin>>CC; cin>>RR; already done
vector<vector<int> > matrix;
for(int i = 0; i<RR; i++)
{
    vector<int> myvector;
    for(int j = 0; j<CC; j++)
    {
        int tempVal = 0;
        cout<<"Enter the number for Matrix 1";
        cin>>tempVal;
        myvector.push_back(tempVal);
    }
    matrix.push_back(myvector);
}

How to enter a series of numbers automatically in Excel

I have a very simple answer. Just put this formula in cell A2:

=Max($A$1:A1)+1

and fill down.

This sets row number automatically, even if you remove some rows or sort rows.

Autosorting numbers of row

How I add Headers to http.get or http.post in Typescript and angular 2?

I have used below code in Angular 9. note that it is using http class instead of normal httpClient.

  1. so import Headers from the module, otherwise Headers will be mistaken by typescript headers interface and gives error

    import {Http, Headers, RequestOptionsArgs } from "@angular/http";

  2. and in your method use following sample code and it is breaked down for easier understanding.

    let customHeaders = new Headers({ Authorization: "Bearer " + localStorage.getItem("token")});
    const requestOptions: RequestOptionsArgs = { headers: customHeaders };
    return this.http.get("/api/orders", requestOptions);
    

What do 'lazy' and 'greedy' mean in the context of regular expressions?

Greedy will consume as much as possible. From http://www.regular-expressions.info/repeat.html we see the example of trying to match HTML tags with <.+>. Suppose you have the following:

<em>Hello World</em>

You may think that <.+> (. means any non newline character and + means one or more) would only match the <em> and the </em>, when in reality it will be very greedy, and go from the first < to the last >. This means it will match <em>Hello World</em> instead of what you wanted.

Making it lazy (<.+?>) will prevent this. By adding the ? after the +, we tell it to repeat as few times as possible, so the first > it comes across, is where we want to stop the matching.

I'd encourage you to download RegExr, a great tool that will help you explore Regular Expressions - I use it all the time.

Why can't static methods be abstract in Java?

Because abstract mehods always need implementation by subclass.But if you make any method to static then overriding is not possible for this method

Example

abstract class foo {
    abstract static void bar2(); 
}


class Bar extends foo {
    //in this if you override foo class static method then it will give error
}

HTML Image not displaying, while the src url works

change the name of the image folder to img and then use the HTML code

How to get package name from anywhere?

Use: BuildConfig.APPLICATION_ID to get PACKAGE NAME anywhere( ie; services, receiver, activity, fragment, etc )

Example: String PackageName = BuildConfig.APPLICATION_ID;

Where does pip install its packages?

pip when used with virtualenv will generally install packages in the path <virtualenv_name>/lib/<python_ver>/site-packages.

For example, I created a test virtualenv named venv_test with Python 2.7, and the django folder is in venv_test/lib/python2.7/site-packages/django.

How to get document height and width without using jquery

You should use getBoundingClientRect as it usually works cross browser and gives you sub-pixel precision on the bounds rectangle.

elem.getBoundingClientRect()

printing a two dimensional array in python

I used numpy to generate the array, but list of lists array should work similarly.

import numpy as np
def printArray(args):
    print "\t".join(args)

n = 10

Array = np.zeros(shape=(n,n)).astype('int')

for row in Array:
    printArray([str(x) for x in row])

If you want to only print certain indices:

import numpy as np
def printArray(args):
    print "\t".join(args)

n = 10

Array = np.zeros(shape=(n,n)).astype('int')

i_indices = [1,2,3]
j_indices = [2,3,4]

for i in i_indices:printArray([str(Array[i][j]) for j in j_indices])

run program in Python shell

If you're wanting to run the script and end at a prompt (so you can inspect variables, etc), then use:

python -i test.py

That will run the script and then drop you into a Python interpreter.

How to simulate a mouse click using JavaScript?

An easier and more standard way to simulate a mouse click would be directly using the event constructor to create an event and dispatch it.

Though the MouseEvent.initMouseEvent() method is kept for backward compatibility, creating of a MouseEvent object should be done using the MouseEvent() constructor.

var evt = new MouseEvent("click", {
    view: window,
    bubbles: true,
    cancelable: true,
    clientX: 20,
    /* whatever properties you want to give it */
});
targetElement.dispatchEvent(evt);

Demo: http://jsfiddle.net/DerekL/932wyok6/

This works on all modern browsers. For old browsers including IE, MouseEvent.initMouseEvent will have to be used unfortunately though it's deprecated.

var evt = document.createEvent("MouseEvents");
evt.initMouseEvent("click", canBubble, cancelable, view,
                   detail, screenX, screenY, clientX, clientY,
                   ctrlKey, altKey, shiftKey, metaKey,
                   button, relatedTarget);
targetElement.dispatchEvent(evt);

When to use Hadoop, HBase, Hive and Pig?

Consider that you work with RDBMS and have to select what to use - full table scans, or index access - but only one of them.
If you select full table scan - use hive. If index access - HBase.

How do I convert an existing callback API to promises?

From the future

A simple generic function I normally use.

const promisify = (fn, ...args) => {
  return new Promise((resolve, reject) => {
    fn(...args, (err, data) => {
      if (err) {
        return reject(err);
      }
      resolve(data);
    });
  });
};

How to use it

   promisify(fn, arg1, arg2)

You are probably not looking to this answer, but this will help understand the inner workings of the available utils

Importing Maven project into Eclipse

I find the m2eclipse plugin to be more useful. This provides nice tools like the POM editor and creating a Maven project from within Eclipse.

Changing the page title with Jquery

i use (and recommend):

$(document).attr("title", "Another Title");

and it works in IE as well this is an alias to

document.title = "Another Title";

Some will debate on wich is better, prop or attr, and since prop call DOM properties and attr Call HTML properties, i think this is actually better...

use this after the DOM Load

$(function(){
    $(document).attr("title", "Another Title");
});

hope this helps.

C# Clear all items in ListView

My guess is that Clear() causes a Changed event to be sent, which in turn triggers an automatic update of your listview from the data source. So this is a feature, not a bug ;-)

Have you tried myListView.Clear() instead of myListView.Items.Clear()? Maybe that works better.

How to convert a UTF-8 string into Unicode?

So the issue is that UTF-8 code unit values have been stored as a sequence of 16-bit code units in a C# string. You simply need to verify that each code unit is within the range of a byte, copy those values into bytes, and then convert the new UTF-8 byte sequence into UTF-16.

public static string DecodeFromUtf8(this string utf8String)
{
    // copy the string as UTF-8 bytes.
    byte[] utf8Bytes = new byte[utf8String.Length];
    for (int i=0;i<utf8String.Length;++i) {
        //Debug.Assert( 0 <= utf8String[i] && utf8String[i] <= 255, "the char must be in byte's range");
        utf8Bytes[i] = (byte)utf8String[i];
    }

    return Encoding.UTF8.GetString(utf8Bytes,0,utf8Bytes.Length);
}

DecodeFromUtf8("d\u00C3\u00A9j\u00C3\u00A0"); // déjà

This is easy, however it would be best to find the root cause; the location where someone is copying UTF-8 code units into 16 bit code units. The likely culprit is somebody converting bytes into a C# string using the wrong encoding. E.g. Encoding.Default.GetString(utf8Bytes, 0, utf8Bytes.Length).


Alternatively, if you're sure you know the incorrect encoding which was used to produce the string, and that incorrect encoding transformation was lossless (usually the case if the incorrect encoding is a single byte encoding), then you can simply do the inverse encoding step to get the original UTF-8 data, and then you can do the correct conversion from UTF-8 bytes:

public static string UndoEncodingMistake(string mangledString, Encoding mistake, Encoding correction)
{
    // the inverse of `mistake.GetString(originalBytes);`
    byte[] originalBytes = mistake.GetBytes(mangledString);
    return correction.GetString(originalBytes);
}

UndoEncodingMistake("d\u00C3\u00A9j\u00C3\u00A0", Encoding(1252), Encoding.UTF8);

Check whether there is an Internet connection available on Flutter app

I found that just using the connectivity package was not enough to tell if the internet was available or not. In Android it only checks if there is WIFI or if mobile data is turned on, it does not check for an actual internet connection . During my testing, even with no mobile signal ConnectivityResult.mobile would return true.

With IOS my testing found that the connectivity plugin does correctly detect if there is an internet connection when the phone has no signal, the issue was only with Android.

The solution I found was to use the data_connection_checker package along with the connectivity package. This just makes sure there is an internet connection by making requests to a few reliable addresses, the default timeout for the check is around 10 seconds.

My finished isInternet function looked a bit like this:

  Future<bool> isInternet() async {
    var connectivityResult = await (Connectivity().checkConnectivity());
    if (connectivityResult == ConnectivityResult.mobile) {
      // I am connected to a mobile network, make sure there is actually a net connection.
      if (await DataConnectionChecker().hasConnection) {
        // Mobile data detected & internet connection confirmed.
        return true;
      } else {
        // Mobile data detected but no internet connection found.
        return false;
      }
    } else if (connectivityResult == ConnectivityResult.wifi) {
      // I am connected to a WIFI network, make sure there is actually a net connection.
      if (await DataConnectionChecker().hasConnection) {
        // Wifi detected & internet connection confirmed.
        return true;
      } else {
        // Wifi detected but no internet connection found.
        return false;
      }
    } else {
      // Neither mobile data or WIFI detected, not internet connection found.
      return false;
    }
  }

The if (await DataConnectionChecker().hasConnection) part is the same for both mobile and wifi connections and should probably be moved to a separate function. I've not done that here to leave it more readable.

This is my first Stack Overflow answer, hope it helps someone.

How to add a custom HTTP header to every WCF call?

You can specify custom headers in the MessageContract.

You can also use < endpoint> headers that are stored in the configuration file and will be copied allong in the header of all the messages sent by the client/service. This is usefull to add some static header easily.

CSS for the "down arrow" on a <select> element?

Try this

   <div style='position:relative;left:0px;top:0px;
        onMouseOver=document.getElementById('visible').style.visibility='visible' 
        id='hidden'>10
   <select style='position:absolute;left:0px;top:0px;cursor:pointer;visibility:hidden;'
        onMouseOut=document.getElementById('visible').style.visibility='hidden'
        onChange='this.form.submit()' 
        id='visible' multiple size='3'>";
   <option selected value=10>10</option>
   <option value=20>20</option>
   <option value=50>50</option>
   </select>
   </div>

PostgreSQL error: Fatal: role "username" does not exist

I installed it on macOS and had to:

cd /Applications/Postgres.app/Contents/Versions/9.5/bin
createuser -U postgres -s YOURUSERNAME
createdb YOURUSERNAME

Here's the source: https://github.com/PostgresApp/PostgresApp/issues/313#issuecomment-192461641

Append same text to every cell in a column in Excel

It's a simple "&" function.

=cell&"yourtexthere"

Example - your cell says Mickey, and you want Mickey Mouse. Mickey is in A2. In B2, type

=A2&" Mouse"

Then, copy and "paste special" for values.

B2 now reads "Mickey Mouse"

Getting unique values in Excel by using formulas only

You could use COUNTIF to get the number of occurence of the value in the range . So if the value is in A3, the range is A1:A6, then in the next column use a IF(EXACT(COUNTIF(A3:$A$6, A3),1), A3, ""). For the A4, it would be IF(EXACT(COUNTIF(A4:$A$6, A3),1), A4, "")

This would give you a column where all unique values are without any duplicate

Login credentials not working with Gmail SMTP

I had same issue. And I fix it with creating an app-password for Email application on Mac. You can find it at my account -> Security -> Signing in to Google -> App passwords. below is the link for it. https://myaccount.google.com/apppasswords?utm_source=google-account&utm_medium=web

Remove IE10's "clear field" X button on certain inputs?

To hide arrows and cross in a "time" input :

#inputId::-webkit-outer-spin-button,
#inputId::-webkit-inner-spin-button,
#inputId::-webkit-clear-button{
    -webkit-appearance: none;
    margin: 0;
}

Count number of columns in a table row

document.getElementById('table1').rows[0].cells.length

cells is not a property of a table, rows are. Cells is a property of a row though

How do I properly set the Datetimeindex for a Pandas datetime object in a dataframe?

To simplify Kirubaharan's answer a bit:

df['Datetime'] = pd.to_datetime(df['date'] + ' ' + df['time'])
df = df.set_index('Datetime')

And to get rid of unwanted columns (as OP did but did not specify per se in the question):

df = df.drop(['date','time'], axis=1)

In C/C++ what's the simplest way to reverse the order of bits in a byte?

I'll chip in my solution, since i can't find anything like this in the answers so far. It is a bit overengineered maybe, but it generates the lookup table using C++14 std::index_sequence in compile time.

#include <array>
#include <utility>

constexpr unsigned long reverse(uint8_t value) {
    uint8_t result = 0;
    for (std::size_t i = 0, j = 7; i < 8; ++i, --j) {
        result |= ((value & (1 << j)) >> j) << i;
    }
    return result;
}

template<size_t... I>
constexpr auto make_lookup_table(std::index_sequence<I...>)
{
    return std::array<uint8_t, sizeof...(I)>{reverse(I)...};   
}

template<typename Indices = std::make_index_sequence<256>>
constexpr auto bit_reverse_lookup_table()
{
    return make_lookup_table(Indices{});
}

constexpr auto lookup = bit_reverse_lookup_table();

int main(int argc)
{
    return lookup[argc];
}

https://godbolt.org/z/cSuWhF

jQuery - multiple $(document).ready ...?

All will get executed and On first Called first run basis!!

<div id="target"></div>

<script>
  $(document).ready(function(){
    jQuery('#target').append('target edit 1<br>');
  });
  $(document).ready(function(){
    jQuery('#target').append('target edit 2<br>');
  });
  $(document).ready(function(){
    jQuery('#target').append('target edit 3<br>');
  });
</script>

Demo As you can see they do not replace each other

Also one thing i would like to mention

in place of this

$(document).ready(function(){});

you can use this shortcut

jQuery(function(){
   //dom ready codes
});

Mocking Extension Methods with Moq

I have used a Wrapper to get around this problem. Create a wrapper object and pass your mocked method.

See Mocking Static Methods for Unit Testing by Paul Irwin, it has nice examples.

jQuery add blank option to top of list and make selected to existing dropdown

This worked:

$("#theSelectId").prepend("<option value='' selected='selected'></option>");

Firebug Output:

<select id="theSelectId">
  <option selected="selected" value=""/>
  <option value="volvo">Volvo</option>
  <option value="saab">Saab</option>
  <option value="mercedes">Mercedes</option>
  <option value="audi">Audi</option>
</select>

You could also use .prependTo if you wanted to reverse the order:

?$("<option>", { value: '', selected: true }).prependTo("#theSelectId");???????????

uncaught syntaxerror unexpected token U JSON

The parameter for the JSON.parse may be returning nothing (i.e. the value given for the JSON.parse is undefined)!

It happened to me while I was parsing the Compiled solidity code from an xyz.sol file.

import web3 from './web3';
import xyz from './build/xyz.json';

const i = new web3.eth.Contract(
  JSON.parse(xyz.interface),
  '0x99Fd6eFd4257645a34093E657f69150FEFf7CdF5'
);

export default i;

which was misspelled as

JSON.parse(xyz.intereface)

which was returning nothing!

Atom menu is missing. How do I re-enable

CONTROL + SHIFT + P and execute command "Tree View: Show"

Android, ListView IllegalStateException: "The content of the adapter has changed but ListView did not receive a notification"

I had a custom ListAdapter and was calling super.notifyDataSetChanged() at the beginning and not the end of the method

@Override
public void notifyDataSetChanged() {
    recalculate();
    super.notifyDataSetChanged();
}

Create File If File Does Not Exist

Yes, you need to negate File.Exists(path) if you want to check if the file doesn't exist.

Change background position with jQuery

Here you go:

$(document).ready(function(){
    $('#submenu li').hover(function(){
        $('#carousel').css('background-position', '10px 10px');
    }, function(){
        $('#carousel').css('background-position', '');
    });
});

How can you export the Visual Studio Code extension list?

Dump extensions:

code --list-extensions > extensions.txt

Install extensions with Bash (Linux, OS X and WSL):

cat extensions.txt | xargs code --list-extensions {}

Install extensions on Windows with PowerShell:

cat extensions.txt |% { code --install-extension $_}

What is wrong with my SQL here? #1089 - Incorrect prefix key

CREATE TABLE `table`.`users` (
    `id` INT(11) NOT NULL AUTO_INCREMENT,
    `username` VARCHAR(50) NOT NULL,
    `password` VARCHAR(50) NOT NULL,
    `dir` VARCHAR(100) NOT NULL,
    PRIMARY KEY (`id`(11))
) ENGINE = MyISAM;

Change To

CREATE TABLE `table`.`users` (
        `id` INT(11) NOT NULL AUTO_INCREMENT,
        `username` VARCHAR(50) NOT NULL,
        `password` VARCHAR(50) NOT NULL,
        `dir` VARCHAR(100) NOT NULL,
        PRIMARY KEY (`id`)
    ) ENGINE = MyISAM;

scrollIntoView Scrolls just too far

Smoothly scroll to a proper position

Get correct y coordinate and use window.scrollTo({top: y, behavior: 'smooth'})

const id = 'profilePhoto';
const yOffset = -10; 
const element = document.getElementById(id);
const y = element.getBoundingClientRect().top + window.pageYOffset + yOffset;

window.scrollTo({top: y, behavior: 'smooth'});

IOError: [Errno 32] Broken pipe: Python

I know this is not the "proper" way to do it, but if you are simply interested in getting rid of the error message, you could try this workaround:

python your_python_code.py 2> /dev/null | other_command

Android Studio with Google Play Services

All those answers are wrong, since the release of gradle plugin v0.4.2 the setup of google play services under android studio is straight forward. You don't need to import any jar or add any project library nor add any new module under android studio. What you have to do is to add the correct dependencies into the build.gradle file. Please take a look to those links: Gradle plugin v0.4.2 update, New Build System, and this sample

The Correct way to do so is as follows:

First of all you have to launch the sdk manager and download and install the following files located under "extras": Android support repository, Google play services, Google repository.

Restart android studio and open the build gradle file. You must modify your build.gradle file to look like this under dependencies:

dependencies {
    compile 'com.google.android.gms:play-services:6.5.87' 
 }

And finally syncronise your project (the button to the left of the AVD manager).

Since version 6.5 you can include the complete library (very large) or just the modules that you need (Best Option). I.e if you only need Google Maps and Analytics you can replace the previous example with the following one:

dependencies {  
    compile 'com.google.android.gms:play-services-base:6.5.87'    
    compile 'com.google.android.gms:play-services-maps:6.5.87'  
}

You can find the complete dependency list here

Some side notes:

  • Use the latest play services library version. If it's an old version, android studio will highlight it. As of today (February 5th is 6.5.87) but you can check the latest version at Gradle Please
  • After a major update of Android Studio, clean an rebuild your project by following the next instructions as suggested in the comments by @user123321

    cd to your project folder
    ./gradlew clean
    ./gradlew build

iframe refuses to display

The reason for the error is that the host server for https://cw.na1.hgncloud.com has provided some HTTP headers to protect the document. One of which is that the frame ancestors must be from the same domain as the original content. It seems you are attempting to put the iframe at a domain location that is not the same as the content of the iframe - thus violating the Content Security Policy that the host has set.

Check out this link on Content Security Policy for more details.

The term 'Get-ADUser' is not recognized as the name of a cmdlet

Open Turn On/Off Windows Features.

Make sure you have Active Directory Domain Services selected. If not, install it. enter image description here

Split a List into smaller lists of N size

While plenty of the answers above do the job, they all fail horribly on a never ending sequence (or a really long sequence). The following is a completely on-line implementation which guarantees best time and memory complexity possible. We only iterate the source enumerable exactly once and use yield return for lazy evaluation. The consumer could throw away the list on each iteration making the memory footprint equal to that of the list w/ batchSize number of elements.

public static IEnumerable<List<T>> BatchBy<T>(this IEnumerable<T> enumerable, int batchSize)
{
    using (var enumerator = enumerable.GetEnumerator())
    {
        List<T> list = null;
        while (enumerator.MoveNext())
        {
            if (list == null)
            {
                list = new List<T> {enumerator.Current};
            }
            else if (list.Count < batchSize)
            {
                list.Add(enumerator.Current);
            }
            else
            {
                yield return list;
                list = new List<T> {enumerator.Current};
            }
        }

        if (list?.Count > 0)
        {
            yield return list;
        }
    }
}

EDIT: Just now realizing the OP asks about breaking a List<T> into smaller List<T>, so my comments regarding infinite enumerables aren't applicable to the OP, but may help others who end up here. These comments were in response to other posted solutions that do use IEnumerable<T> as an input to their function, yet enumerate the source enumerable multiple times.

Resolving javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path building failed Error?

I want to chime in since I have a QEMU environment where I have to download files in java. It turns out the /etc/ssl/certs/java/cacerts in QEMU does have problem because it does not match the /etc/ssl/certs/java/cacerts in the host environment. The host environment is behind a company proxy so the java cacerts is a customized version.

If you are using a QEMU environment, make sure the host system can access files first. For example you can try this script on your host machine first to see. If the script runs just fine in host machine but not in QEMU, then you are having the same problem as me.

To solve this issue, I had to make a backup of the original file in QEMU, copy over the file in host environment to the QEMU chroot jail, and then java could download files normally in QEMU.

A better solution would be mount the /etc into the QEMU environment; however I am not sure if other files will get impacted in this process. So I decided to use this ugly but easy work-around.

What is the difference between varchar and varchar2 in Oracle?

Taken from the latest stable Oracle production version 12.2: Data Types

The major difference is that VARCHAR2 is an internal data type and VARCHAR is an external data type. So we need to understand the difference between an internal and external data type...

Inside a database, values are stored in columns in tables. Internally, Oracle represents data in particular formats known as internal data types.

In general, OCI (Oracle Call Interface) applications do not work with internal data type representations of data, but with host language data types that are predefined by the language in which they are written. When data is transferred between an OCI client application and a database table, the OCI libraries convert the data between internal data types and external data types.

External types provide a convenience for the programmer by making it possible to work with host language types instead of proprietary data formats. OCI can perform a wide range of data type conversions when transferring data between an Oracle database and an OCI application. There are more OCI external data types than Oracle internal data types.

The VARCHAR2 data type is a variable-length string of characters with a maximum length of 4000 bytes. If the init.ora parameter max_string_size is default, the maximum length of a VARCHAR2 can be 4000 bytes. If the init.ora parameter max_string_size = extended, the maximum length of a VARCHAR2 can be 32767 bytes

The VARCHAR data type stores character strings of varying length. The first 2 bytes contain the length of the character string, and the remaining bytes contain the string. The specified length of the string in a bind or a define call must include the two length bytes, so the largest VARCHAR string that can be received or sent is 65533 bytes long, not 65535.

A quick test in a 12.2 database suggests that as an internal data type, Oracle still treats a VARCHAR as a pseudotype for VARCHAR2. It is NOT a SYNONYM which is an actual object type in Oracle.

SQL> select substr(banner,1,80) from v$version where rownum=1;
Oracle Database 12c Enterprise Edition Release 12.2.0.1.0 - 64bit Production    

SQL> create table test (my_char varchar(20));
Table created.

SQL> desc test
Name                 Null?    Type
MY_CHAR                       VARCHAR2(20)

There are also some implications of VARCHAR for ProC/C++ Precompiler options. For programmers who are interested, the link is at: Pro*C/C++ Programmer's Guide

Convert file path to a file URI?

The System.Uri constructor has the ability to parse full file paths and turn them into URI style paths. So you can just do the following:

var uri = new System.Uri("c:\\foo");
var converted = uri.AbsoluteUri;

How to clear the JTextField by clicking JButton

Looking for EventHandling, ActionListener?

or code?

JButton b = new JButton("Clear");
b.addActionListener(new ActionListener(){
    public void actionPerformed(ActionEvent e){
        textfield.setText("");
        //textfield.setText(null); //or use this
    }
});

Also See
How to Use Buttons

How to add manifest permission to an application?

If you are using the Eclipse ADT plugin for your development, open AndroidManifest.xml in the Android Manifest Editor (should be the default action for opening AndroidManifest.xml from the project files list).

Afterwards, select the Permissions tab along the bottom of the editor (Manifest - Application - Permissions - Instrumentation - AndroidManifest.xml), then click Add... a Uses Permission and select the desired permission from the dropdown on the right, or just copy-paste in the necessary one (such as the android.permission.INTERNET permission you required).

Proper way of checking if row exists in table in PL/SQL block

You can do EXISTS in Oracle PL/SQL.

You can do the following:

DECLARE
    n_rowExist NUMBER := 0;
BEGIN
    SELECT CASE WHEN EXISTS (
      SELECT 1
      FROM person
      WHERE ID = 10
    ) THEN 1 ELSE 0 INTO n_rowExist END FROM DUAL;
    
    IF n_rowExist = 1 THEN
       -- do things when it exists
    ELSE
       -- do things when it doesn't exist
    END IF;

END;
/

Explanation:

In the query nested where it starts with SELECT CASE WHEN EXISTS and after the parenthesis (SELECT 1 FROM person WHERE ID = 10) it will return a result if it finds a person of ID of 10. If the there's a result on the query then it will assign the value of 1 otherwise it will assign the value of 0 to n_rowExist variable. Afterwards, the if statement checks if the value returned equals to 1 then is true otherwise it will be 0 = 1 and that is false.

Create zip file and ignore directory structure

Retain the parent directory so unzip doesn't spew files everywhere

When zipping directories, keeping the parent directory in the archive will help to avoid littering your current directory when you later unzip the archive file

So to avoid retaining all paths, and since you can't use -j and -r together ( you'll get an error ), you can do this instead:

cd path/to/parent/dir/;
zip -r ../my.zip ../$(basename $PWD)
cd -;

The ../$(basename $PWD) is the magic that retains the parent directory.

So now unzip my.zip will give a folder containing all your files:

parent-directory
+-- file1
+-- file2
+-- dir1
¦   +-- file3
¦   +-- file4

Instead of littering the current directory with the unzipped files:

file1
file2
dir1
+-- file3
+-- file4

jQuery check if attr = value

jQuery's attr method returns the value of the attribute:

The .attr() method gets the attribute value for only the first element in the matched set. To get the value for each element individually, use a looping construct such as jQuery's .each() or .map() method.

All you need is:

$('html').attr('lang') == 'fr-FR'

However, you might want to do a case-insensitive match:

$('html').attr('lang').toLowerCase() === 'fr-fr'

jQuery's val method returns the value of a form element.

The .val() method is primarily used to get the values of form elements such as input, select and textarea. In the case of <select multiple="multiple"> elements, the .val() method returns an array containing each selected option; if no option is selected, it returns null.

Resize Cross Domain Iframe Height

Minimum crossdomain set I've used for embedding fitted single iframe on a page.

On embedding page (containing iframe):

<iframe frameborder="0" id="sizetracker" src="http://www.hurtta.com/Services/SizeTracker/DE" width="100%"></iframe>
<script type="text/javascript">
  // Create browser compatible event handler.
  var eventMethod = window.addEventListener ? "addEventListener" : "attachEvent";
  var eventer = window[eventMethod];
  var messageEvent = eventMethod == "attachEvent" ? "onmessage" : "message";
  // Listen for a message from the iframe.
  eventer(messageEvent, function(e) {
    if (isNaN(e.data)) return;

    // replace #sizetracker with what ever what ever iframe id you need
    document.getElementById('sizetracker').style.height = e.data + 'px';

  }, false);
</script>

On embedded page (iframe):

<script type="text/javascript">
function sendHeight()
{
    if(parent.postMessage)
    {
        // replace #wrapper with element that contains 
        // actual page content
        var height= document.getElementById('wrapper').offsetHeight;
        parent.postMessage(height, '*');
    }
}

// Create browser compatible event handler.
var eventMethod = window.addEventListener ? "addEventListener" : "attachEvent";
var eventer = window[eventMethod];
var messageEvent = eventMethod == "attachEvent" ? "onmessage" : "message";

// Listen for a message from the iframe.
eventer(messageEvent, function(e) {

    if (isNaN(e.data)) return;

    sendHeight();

}, 
false);
</script>

How to force garbage collector to run?

GC.Collect() 

from MDSN,

Use this method to try to reclaim all memory that is inaccessible.

All objects, regardless of how long they have been in memory, are considered for collection; however, objects that are referenced in managed code are not collected. Use this method to force the system to try to reclaim the maximum amount of available memory.

Reading an Excel file in PHP

Read XLSX (Excel 97-2003)
https://github.com/shuchkin/simplexls

if ( $xls = SimpleXLS::parse('book.xls') ) {
    print_r( $xls->rows() );
} else {
    echo SimpleXLS::parseError();
}

Read XLSX (Excel 2003+)
https://github.com/shuchkin/simplexlsx

if ( $xlsx = SimpleXLSX::parse('book.xlsx') ) {
    print_r( $xlsx->rows() );
} else {
    echo SimpleXLSX::parseError();
}

Output

Array (
    [0] => Array
        (
            [0] => ISBN
            [1] => title
            [2] => author
            [3] => publisher
            [4] => ctry
        )
    [1] => Array
        (
            [0] => 618260307
            [1] => The Hobbit
            [2] => J. R. R. Tolkien
            [3] => Houghton Mifflin
            [4] => USA
       )

)

CSV php reader
https://github.com/shuchkin/simplecsv

Android WebView style background-color:transparent ignored on android 2.2

The most important thing was not mentioned.

The html must have a body tag with background-color set to transparent.

So the full solution would be:


HTML

    <body style="display: flex; background-color:transparent">some content</body>

Activity

    WebView wv = (WebView) findViewById(R.id.webView);
    wv.setBackgroundColor(0);
    wv.setLayerType(View.LAYER_TYPE_SOFTWARE, null);
    wv.loadUrl("file:///android_asset/myview.html");

How do I run a batch file from my Java Application?

I had the same issue. However sometimes CMD failed to run my files. That's why i create a temp.bat on my desktop, next this temp.bat is going to run my file, and next the temp file is going to be deleted.

I know this is a bigger code, however worked for me in 100% when even Runtime.getRuntime().exec() failed.

// creating a string for the Userprofile (either C:\Admin or whatever)
String userprofile = System.getenv("USERPROFILE");

BufferedWriter writer = null;
        try {
            //create a temporary file
            File logFile = new File(userprofile+"\\Desktop\\temp.bat");   
            writer = new BufferedWriter(new FileWriter(logFile));

            // Here comes the lines for the batch file!
            // First line is @echo off
            // Next line is the directory of our file
            // Then we open our file in that directory and exit the cmd
            // To seperate each line, please use \r\n
            writer.write("cd %ProgramFiles(x86)%\\SOME_FOLDER \r\nstart xyz.bat \r\nexit");
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                // Close the writer regardless of what happens...
                writer.close();
            } catch (Exception e) {
            }

        }

        // running our temp.bat file
        Runtime rt = Runtime.getRuntime();
        try {

            Process pr = rt.exec("cmd /c start \"\" \""+userprofile+"\\Desktop\\temp.bat" );
            pr.getOutputStream().close();
        } catch (IOException ex) {
            Logger.getLogger(MainFrame.class.getName()).log(Level.SEVERE, null, ex);

        }
        // deleting our temp file
        File databl = new File(userprofile+"\\Desktop\\temp.bat");
        databl.delete();

How do I reference to another (open or closed) workbook, and pull values back, in VBA? - Excel 2007

You will have to open the file in one way or another if you want to access the data within it. Obviously, one way is to open it in your Excel application instance, e.g.:-

(untested code)

Dim wbk As Workbook
Set wbk = Workbooks.Open("C:\myworkbook.xls")

' now you can manipulate the data in the workbook anyway you want, e.g. '

Dim x As Variant
x = wbk.Worksheets("Sheet1").Range("A6").Value

Call wbk.Worksheets("Sheet2").Range("A1:G100").Copy
Call ThisWorbook.Worksheets("Target").Range("A1").PasteSpecial(xlPasteValues)
Application.CutCopyMode = False

' etc '

Call wbk.Close(False)

Another way to do it would be to use the Excel ADODB provider to open a connection to the file and then use SQL to select data from the sheet you want, but since you are anyway working from within Excel I don't believe there is any reason to do this rather than just open the workbook. Note that there are optional parameters for the Workbooks.Open() method to open the workbook as read-only, etc.

Invoke a second script with arguments from a script

We can use splatting for this:

& $command @args

where @args (automatic variable $args) is splatted into array of parameters.

Under PS, 5.1

How do I drop a foreign key in SQL Server?

I think this will helpful to you...

DECLARE @ConstraintName nvarchar(200)
SELECT 
    @ConstraintName = KCU.CONSTRAINT_NAME
FROM INFORMATION_SCHEMA.REFERENTIAL_CONSTRAINTS AS RC 
INNER JOIN INFORMATION_SCHEMA.KEY_COLUMN_USAGE AS KCU
    ON KCU.CONSTRAINT_CATALOG = RC.CONSTRAINT_CATALOG  
    AND KCU.CONSTRAINT_SCHEMA = RC.CONSTRAINT_SCHEMA 
    AND KCU.CONSTRAINT_NAME = RC.CONSTRAINT_NAME
WHERE
    KCU.TABLE_NAME = 'TABLE_NAME' AND
    KCU.COLUMN_NAME = 'TABLE_COLUMN_NAME'
IF @ConstraintName IS NOT NULL EXEC('alter table TABLE_NAME drop  CONSTRAINT ' + @ConstraintName)

It will delete foreign Key Constraint based on specific table and column.

Https to http redirect using htaccess

RewriteCond %{HTTP:X-Forwarded-Proto} =https

How do I set the proxy to be used by the JVM

reading an XML file and needs to download its schema

If you are counting on retrieving schemas or DTDs over the internet, you're building a slow, chatty, fragile application. What happens when that remote server hosting the file takes planned or unplanned downtime? Your app breaks. Is that OK?

See http://xml.apache.org/commons/components/resolver/resolver-article.html#s.catalog.files

URL's for schemas and the like are best thought of as unique identifiers. Not as requests to actually access that file remotely. Do some google searching on "XML catalog". An XML catalog allows you to host such resources locally, resolving the slowness, chattiness and fragility.

It's basically a permanently cached copy of the remote content. And that's OK, since the remote content will never change. If there's ever an update, it'd be at a different URL. Making the actual retrieval of the resource over the internet especially silly.

How can I open two pages from a single click without using JavaScript?

it is working perfectly by only using html

<p><a href="#"onclick="window.open('http://google.com');window.open('http://yahoo.com');">Click to open Google and Yahoo</a></p>

Can't stop rails server

I used killall -9 rails like Sri suggested and it didn't work. I adjusted the command to killall -9 ruby and the server closed immediately.

Tl;dr: killall -9 ruby

What is the MySQL JDBC driver connection string?

Check if the Driver Connector jar matches the SQL version.

I was also getting the same error as I was using the

mySQl-connector-java-5.1.30.jar

with MySql 8

How do I measure request and response times at once using cURL?

here is the string you can use with -w, contains all options that curl -w supports.

{"contentType":"%{content_type}","filenameEffective":"%{filename_effective}","ftpEntryPath":"%{ftp_entry_path}","httpCode":"%{http_code}","httpConnect":"%{http_connect}","httpVersion":"%{http_version}","localIp":"%{local_ip}","localPort":"%{local_port}","numConnects":"%{num_connects}","numRedirects":"%{num_redirects}","proxySslVerifyResult":"%{proxy_ssl_verify_result}","redirectUrl":"%{redirect_url}","remoteIp":"%{remote_ip}","remotePort":"%{remote_port}","scheme":"%{scheme}","size":{"download":"%{size_download}","header":"%{size_header}","request":"%{size_request}","upload":"%{size_upload}"},"speed":{"download":"%{speed_download}","upload":"%{speed_upload}"},"sslVerifyResult":"%{ssl_verify_result}","time":{"appconnect":"%{time_appconnect}","connect":"%{time_connect}","namelookup":"%{time_namelookup}","pretransfer":"%{time_pretransfer}","redirect":"%{time_redirect}","starttransfer":"%{time_starttransfer}","total":"%{time_total}"},"urlEffective":"%{url_effective}"}

outputs JSON.

Tomcat - maxThreads vs maxConnections

Tomcat can work in 2 modes:

  • BIO – blocking I/O (one thread per connection)
  • NIOnon-blocking I/O (many more connections than threads)

Tomcat 7 is BIO by default, although consensus seems to be "don't use Bio because Nio is better in every way". You set this using the protocol parameter in the server.xml file.

  • BIO will be HTTP/1.1 or org.apache.coyote.http11.Http11Protocol
  • NIO will be org.apache.coyote.http11.Http11NioProtocol

If you're using BIO then I believe they should be more or less the same.

If you're using NIO then actually "maxConnections=1000" and "maxThreads=10" might even be reasonable. The defaults are maxConnections=10,000 and maxThreads=200. With NIO, each thread can serve any number of connections, switching back and forth but retaining the connection so you don't need to do all the usual handshaking which is especially time-consuming with HTTPS but even an issue with HTTP. You can adjust the "keepAlive" parameter to keep connections around for longer and this should speed everything up.

Convert String to Type in C#

You can only use just the name of the type (with its namespace, of course) if the type is in mscorlib or the calling assembly. Otherwise, you've got to include the assembly name as well:

Type type = Type.GetType("Namespace.MyClass, MyAssembly");

If the assembly is strongly named, you've got to include all that information too. See the documentation for Type.GetType(string) for more information.

Alternatively, if you have a reference to the assembly already (e.g. through a well-known type) you can use Assembly.GetType:

Assembly asm = typeof(SomeKnownType).Assembly;
Type type = asm.GetType(namespaceQualifiedTypeName);

Controller 'ngModel', required by directive '...', can't be found

You can also remove the line

  require: 'ngModel',

if you don't need ngModel in this directive. Removing ngModel will allow you to make a directive without thatngModel error.

Using Jquery AJAX function with datatype HTML

Here is a version that uses dataType html, but this is far less explicit, because i am returning an empty string to indicate an error.

Ajax call:

$.ajax({
  type : 'POST',
  url : 'post.php',
  dataType : 'html',
  data: {
      email : $('#email').val()
  },
  success : function(data){
      $('#waiting').hide(500);
      $('#message').removeClass().addClass((data == '') ? 'error' : 'success')
     .html(data).show(500);
      if (data == '') {
          $('#message').html("Format your email correcly");
          $('#demoForm').show(500);
      }
  },
  error : function(XMLHttpRequest, textStatus, errorThrown) {
      $('#waiting').hide(500);
      $('#message').removeClass().addClass('error')
      .text('There was an error.').show(500);
      $('#demoForm').show(500);
  }

});

post.php

<?php
sleep(1);

function processEmail($email) {
    if (preg_match("#^[a-zA-Z0-9_.-]+@[a-zA-Z0-9-]+.[a-zA-Z0-9-.]+$#", $email)) {
        // your logic here (ex: add into database)
        return true;
    }
    return false;
}

if (processEmail($_POST['email'])) {
    echo "<span>Your email is <strong>{$_POST['email']}</strong></span>";
}

react-native :app:installDebug FAILED

open avd manager click on the arrow next to the pencil icon and wipe data works for me...

How to hide a button programmatically?

Try the below code -

playButton.setVisibility(View.INVISIBLE);

or -

playButton.setVisibility(View.GONE);

show it again with -

playButton.setVisibility(View.VISIBLE);

Whether a variable is undefined

jQuery.val() and .text() will never return 'undefined' for an empty selection. It always returns an empty string (i.e. ""). .html() will return null if the element doesn't exist though.You need to do:

if(page_name != '')

For other variables that don't come from something like jQuery.val() you would do this though:

if(typeof page_name != 'undefined')

You just have to use the typeof operator.

Insert picture/table in R Markdown

In March I made a deck presentation in slidify, Rmarkdown with impress.js which is a cool 3D framework. My index.Rmdheader looks like

---
title       : French TER (regional train) monthly regularity
subtitle    : since January 2013
author      : brigasnuncamais
job         : Business Intelligence / Data Scientist consultant
framework   : impressjs     # {io2012, html5slides, shower, dzslides, ...}
highlighter : highlight.js  # {highlight.js, prettify, highlight}
hitheme     : tomorrow      # 
widgets     : []            # {mathjax, quiz, bootstrap}
mode        : selfcontained # {standalone, draft}
knit        : slidify::knit2slides

subdirs are:

/assets /css    /impress-demo.css
        /fig    /unnamed-chunk-1-1.png (generated by included R code)
        /img    /SS850452.png (my image used as background)
        /js     /impress.js
        /layouts/custbg.html # content:--- layout: slide --- {{{ slide.html }}}
        /libraries  /frameworks /impressjs
                                /io2012
                    /highlighters   /highlight.js
                                    /impress.js
index.Rmd

A slide with image in background code snippet would be in my .Rmd:

<div id="bg">
  <img src="assets/img/SS850452.png" alt="">
</div>  

Some issues appeared since I last worked on it (photos are no more in background, text it too large on my R plot) but it works fine on my local. Troubles come when I run it on RPubs.

adb shell command to make Android package uninstall dialog appear

In my case, I do an adb shell pm list packages to see first what are the packages/apps installed in my Android device or emulator, then upon locating the desired package/app, I do an adb shell pm uninstall -k com.package.name.

Differences between contentType and dataType in jQuery ajax function

enter image description here

In English:

  • ContentType: When sending data to the server, use this content type. Default is application/x-www-form-urlencoded; charset=UTF-8, which is fine for most cases.
  • Accepts: The content type sent in the request header that tells the server what kind of response it will accept in return. Depends on DataType.
  • DataType: The type of data that you're expecting back from the server. If none is specified, jQuery will try to infer it based on the MIME type of the response. Can be text, xml, html, script, json, jsonp.

Could not find method compile() for arguments Gradle

Just for the record: I accidentally enabled Offline work under Preferences -> Build,Execution,Deployment -> Gradle -> uncheck Offline Work, but the error message was misleading

how get yesterday and tomorrow datetime in c#

The trick is to use "DateTime" to manipulate dates; only use integers and strings when you need a "final result" from the date.

For example (pseudo code):

  1. Get "DateTime tomorrow = Now + 1"

  2. Determine date, day of week, day of month - whatever you want - of the resulting date.

constant pointer vs pointer on a constant value

The first is a constant pointer to a char and the second is a pointer to a constant char. You didn't touch all the cases in your code:

char * const pc1 = &a; /* You can't make pc1 point to anything else */
const char * pc2 = &a; /* You can't dereference pc2 to write. */

*pc1 = 'c' /* Legal. */
*pc2 = 'c' /* Illegal. */

pc1 = &b; /* Illegal, pc1 is a constant pointer. */
pc2 = &b; /* Legal, pc2 itself is not constant. */

image processing to improve tesseract OCR accuracy

you can do noise reduction and then apply thresholding, but that you can you can play around with the configuration of the OCR by changing the --psm and --oem values

try: --psm 5 --oem 2

you can also look at the following link for further details here

Inserting an item in a Tuple

For the case where you are not adding to the end of the tuple

>>> a=(1,2,3,5,6)
>>> a=a[:3]+(4,)+a[3:]
>>> a
(1, 2, 3, 4, 5, 6)
>>> 

How do I remove the blue styling of telephone numbers on iPhone/iOS?

Putting the number in a <fieldset> will prevent iOS from converting the number to a link for some reason. In some cases this could be the right solution. I don't advocate a blanket disabling of converting to links.

Visual studio - getting error "Metadata file 'XYZ' could not be found" after edit continue

I had same issue too.

In my case, I recently add an internal class to somewhere in project. One of the dependencies in solution has same class name and both of them are added correctly to references.

I changed my last activity and rebuild, it works.

Be sure that your compiler messages are valid. In my case I catch reference error from there, not listed as an error in Error List.

How do I remedy "The breakpoint will not currently be hit. No symbols have been loaded for this document." warning?

it was so easyyyy. it also happend for me because .pdb file of the project have not copy in debug\Bin folder then it could not load symboles (.pdb file) in debug mode . in this way : you must rebuild your target project and manually copy the symboles (.pdb file) in debug\Bin folder of execute project

What is a classpath and how do I set it?

Think of it as Java's answer to the PATH environment variable - OSes search for EXEs on the PATH, Java searches for classes and packages on the classpath.

Spring Security exclude url patterns in security annotation configurartion

Where are you configuring your authenticated URL pattern(s)? I only see one uri in your code.

Do you have multiple configure(HttpSecurity) methods or just one? It looks like you need all your URIs in the one method.

I have a site which requires authentication to access everything so I want to protect /*. However in order to authenticate I obviously want to not protect /login. I also have static assets I'd like to allow access to (so I can make the login page pretty) and a healthcheck page that shouldn't require auth.

In addition I have a resource, /admin, which requires higher privledges than the rest of the site.

The following is working for me.

@Override
protected void configure(HttpSecurity http) throws Exception {

    http.authorizeRequests()
        .antMatchers("/login**").permitAll()
        .antMatchers("/healthcheck**").permitAll()
        .antMatchers("/static/**").permitAll()
        .antMatchers("/admin/**").access("hasRole('ROLE_ADMIN')")
        .antMatchers("/**").access("hasRole('ROLE_USER')")
        .and()
            .formLogin().loginPage("/login").failureUrl("/login?error")
                .usernameParameter("username").passwordParameter("password")
        .and()
            .logout().logoutSuccessUrl("/login?logout")
        .and()
            .exceptionHandling().accessDeniedPage("/403")
        .and()
            .csrf();

}

NOTE: This is a first match wins so you may need to play with the order. For example, I originally had /** first:

        .antMatchers("/**").access("hasRole('ROLE_USER')")
        .antMatchers("/login**").permitAll()
        .antMatchers("/healthcheck**").permitAll()

Which caused the site to continually redirect all requests for /login back to /login. Likewise I had /admin/** last:

        .antMatchers("/**").access("hasRole('ROLE_USER')")
        .antMatchers("/admin/**").access("hasRole('ROLE_ADMIN')")

Which resulted in my unprivledged test user "guest" having access to the admin interface (yikes!)

How to get complete current url for Cakephp

After a few research, I got this as perfect Full URL for CakePHP 3.*

$this->request->getUri();

the Full URL will be something like this

http://example.com/books/edit/12

More info you can read here: https://pritomkumar.blogspot.com/2017/04/how-to-get-complete-current-url-for.html

White space showing up on right side of page when background image should extend full length of page

I was experiencing the white line to the right on my iPad as well in horizontal position only. I was using a fixed-position div with a background set to 960px wide and z-index of -999. This particular div only shows up on an iPad due to a media query. Content was then placed into a 960px wide div wrapper. The answers provided on this page were not helping in my case. To fix the white stripe issue I changed the width of the content wrapper to 958px. Voilá. No more white right white stripe on the iPad in horizontal position.

How to create a new schema/new user in Oracle Database 11g?

SQL> select Username from dba_users
  2  ;

USERNAME
------------------------------
SYS
SYSTEM
ANONYMOUS
APEX_PUBLIC_USER
FLOWS_FILES
APEX_040000
OUTLN
DIP
ORACLE_OCM
XS$NULL
MDSYS

USERNAME
------------------------------
CTXSYS
DBSNMP
XDB
APPQOSSYS
HR

16 rows selected.

SQL> create user testdb identified by password;

User created.

SQL> select username from dba_users;

USERNAME
------------------------------
TESTDB
SYS
SYSTEM
ANONYMOUS
APEX_PUBLIC_USER
FLOWS_FILES
APEX_040000
OUTLN
DIP
ORACLE_OCM
XS$NULL

USERNAME
------------------------------
MDSYS
CTXSYS
DBSNMP
XDB
APPQOSSYS
HR

17 rows selected.

SQL> grant create session to testdb;

Grant succeeded.

SQL> create tablespace testdb_tablespace
  2  datafile 'testdb_tabspace.dat'
  3  size 10M autoextend on;

Tablespace created.

SQL> create temporary tablespace testdb_tablespace_temp
  2  tempfile 'testdb_tabspace_temp.dat'
  3  size 5M autoextend on;

Tablespace created.

SQL> drop user testdb;

User dropped.

SQL> create user testdb
  2  identified by password
  3  default tablespace testdb_tablespace
  4  temporary tablespace testdb_tablespace_temp;

User created.

SQL> grant create session to testdb;

Grant succeeded.

SQL> grant create table to testdb;

Grant succeeded.

SQL> grant unlimited tablespace to testdb;

Grant succeeded.

SQL>

set option "selected" attribute from dynamic created option

I was trying something like this using the $(...).val() function, but the function did not exist. It turns out that you can manually set the value the same way you do it for an <input>:

// Set value to Indonesia ("ID"):
$('#country').value = 'ID'

...and it get's automatically updated in the select. Works on Firefox at least; you might want to try it out in the others.

PostgreSQL database service

Use services (start -> run -> services.msc) and look for the postgresql-[version] service.

  • If it is not there you might have just installed pgAdmin and not installed PostgreSQL itself.
  • If it is not running try to start it, if it won't start open the event-viewer (start -> run -> eventvwr) and look for error messages relating to the PostgreSQL service.
  • If it does start check the startup type, if you want it to start with windows it should be "Automatic"; or perhaps "Automatic, delayed start" if you don't want it to slow down startup too much.

Adding to the first, because in a different comment you've said the service isn't there. It is possible to download a standalone pgAdmin so you can connect to an external PostgreSQL database. It would seem you have done such a thing, or explicitly chosen to not add the service. Just try the One Click Installer, which still allows proper configuration of installation directory despite its name.

Getting only response header from HTTP POST using curl

-D, --dump-header <file>
       Write the protocol headers to the specified file.

       This  option  is handy to use when you want to store the headers
       that a HTTP site sends to you. Cookies from  the  headers  could
       then  be  read  in  a  second  curl  invocation by using the -b,
       --cookie option! The -c, --cookie-jar option is however a better
       way to store cookies.

and

-S, --show-error
       When used with -s, --silent, it makes curl show an error message if it fails.

and

-L/--location
      (HTTP/HTTPS) If the server reports that the requested page has moved to a different location (indicated with a Location: header and a 3XX response
      code), this option will make curl redo the request on the new place. If used together with -i/--include or -I/--head, headers from  all  requested
      pages  will  be  shown.  When authentication is used, curl only sends its credentials to the initial host. If a redirect takes curl to a different
      host, it won’t be able to intercept the user+password. See also --location-trusted on how to change this. You can limit the amount of redirects to
      follow by using the --max-redirs option.

      When curl follows a redirect and the request is not a plain GET (for example POST or PUT), it will do the following request with a GET if the HTTP
      response was 301, 302, or 303. If the response code was any other 3xx code, curl will re-send the following  request  using  the  same  unmodified
      method.

from the man page. so

curl -sSL -D - www.acooke.org -o /dev/null

follows redirects, dumps the headers to stdout and sends the data to /dev/null (that's a GET, not a POST, but you can do the same thing with a POST - just add whatever option you're already using for POSTing data)

note the - after the -D which indicates that the output "file" is stdout.

How to download Visual Studio 2017 Community Edition for offline installation?

The command above worked for me

C:\Users\marcelo\Downloads\vs_community.exe --lang en-en --layout C:\VisualStudio2017 --all

How to check if a column exists in a SQL Server table?

I needed similar for SQL SERVER 2000 and, as @Mitch points out, this only works inm 2005+.

Should it help anyone else, this is what worked for me in the end:

if exists (
    select * 
    from 
        sysobjects, syscolumns 
    where 
        sysobjects.id = syscolumns.id 
        and sysobjects.name = 'table' 
        and syscolumns.name = 'column')

How can I display an RTSP video stream in a web page?

For purposes like this one I use VLC as a redistribution server. You said you get to catch the video with VLC? Right-click on the media in VLC, select "stream" and choose your options. You can also do it with command line, which gives you potential benefits of various option (transcoding, scaling, compressing, desinterlacing). Here is a batch that starts VLC distribution from source to its own 555 port (so you will have to type rstp://myvlcserveripaddress:555 in your src option on the webpage to get the stream)

cd \
cd C:\Program Files (x86)\VideoLAN\VLC\

vlc --logo-file C:\logo.png --logo-position 5 --logo-opacity 200 --logo-x 900 --logo-y -2 "mmsh://typeyoursourceIPhere:554" :sout=#transcode{vcodec=div3,vb=800,scale=0,acodec=mpga,ab=128,channels=2,samplerate=44100}:duplicate{dst=rtp{mux=ts,sdp=rtsp://:555/stream}} :sout-all :sout-keep

Here, you have a sample of a webpage that embeds player (based on VLC plugin).

Best practices when running Node.js with port 80 (Ubuntu / Linode)

Drop root privileges after you bind to port 80 (or 443).

This allows port 80/443 to remain protected, while still preventing you from serving requests as root:

function drop_root() {
    process.setgid('nobody');
    process.setuid('nobody');
}

A full working example using the above function:

var process = require('process');
var http = require('http');
var server = http.createServer(function(req, res) {
    res.write("Success!");
    res.end();
});

server.listen(80, null, null, function() {
    console.log('User ID:',process.getuid()+', Group ID:',process.getgid());
    drop_root();
    console.log('User ID:',process.getuid()+', Group ID:',process.getgid());
});

See more details at this full reference.

how to end ng serve or firebase serve

ctrl + c OR ctrl + Pause/Break

Both will ask for Terminate batch job, then press Y or y and click enter.

echo key and value of an array without and with loop

foreach($page as $key => $value) {
  echo "$key is at $value";
}

For 'without loop' version I'll just ask "why?"

int *array = new int[n]; what is this function actually doing?

It allocates that much space according to the value of n and pointer will point to the array i.e the 1st element of array

int *array = new int[n];

How to import large sql file in phpmyadmin

3 things you have to do:

in php.ini of your php installation (note: depending if you want it for CLI, apache, or nginx, find the right php.ini to manipulate)

post_max_size=500M

upload_max_filesize=500M

memory_limit=900M

or set other values.

Restart/reload apache if you have apache installed or php-fpm for nginx if you use nginx.

Remote server?

increase max_execution_time as well, as it will take time to upload the file.

NGINX installation?

you will have to add: client_max_body_size 912M; in /etc/nginx/nginx.conf to the http{...} block

Convert Decimal to Varchar

Hope this will help .

DECLARE  @emp_cond nvarchar(Max) =' ',@LOCATION_ID  NUMERIC(18,0)   
SET@LOCATION_ID=10110000000
IF CAST(@LOCATION_ID AS VARCHAR(18))<>' ' 
            BEGIN
                SELECT @emp_cond= @emp_cond + N' AND 
CM.STATIC_EMP_INFO.EMP_ID = ' ' '+  CAST(@LOCATION_ID AS VARCHAR(18))  +' ' ' '
           END
print  @emp_cond  
EXEC( @emp_cond) 

How to show only next line after the matched one?

Piping is your friend...

Use grep -A1 to show the next line after a match, then pipe the result to tail and only grab 1 line,

cat logs/info.log | grep "term" -A1 | tail -n 1

Max value of Xmx and Xms in Eclipse?

I am guessing you are using a 32 bit eclipse with 32 bit JVM. It wont allow heapsize above what you have specified.

Using a 64-bit Eclipse with a 64-bit JVM helps you to start up eclipse with much larger memory. (I am starting with -Xms1024m -Xmx4000m)

How to set a Javascript object values dynamically?

myObj[prop] = value;

That should work. You mixed up the name of the variable and its value. But indexing an object with strings to get at its properties works fine in JavaScript.

x86 Assembly on a Mac

The features available to use are dependent on your processor. Apple uses the same Intel stuff as everybody else. So yes, generic x86 should be fine (assuming you're not on a PPC :D).

As far as tools go, I think your best bet is a good text editor that 'understands' assembly.

How to correctly implement custom iterators and const_iterators?

  • Choose type of iterator which fits your container: input, output, forward etc.
  • Use base iterator classes from standard library. For example, std::iterator with random_access_iterator_tag.These base classes define all type definitions required by STL and do other work.
  • To avoid code duplication iterator class should be a template class and be parametrized by "value type", "pointer type", "reference type" or all of them (depends on implementation). For example:

    // iterator class is parametrized by pointer type
    template <typename PointerType> class MyIterator {
        // iterator class definition goes here
    };
    
    typedef MyIterator<int*> iterator_type;
    typedef MyIterator<const int*> const_iterator_type;
    

    Notice iterator_type and const_iterator_type type definitions: they are types for your non-const and const iterators.

See Also: standard library reference

EDIT: std::iterator is deprecated since C++17. See a relating discussion here.

iOS 8 Snapshotting a view that has not been rendered results in an empty snapshot

You can silence the "Snapshotting a view" warning by referencing the view property before presenting the view controller. Doing so causes the view to load and allows iOS render it before taking the snapshot.

UIAlertController *controller = [UIAlertController alertControllerWithTitle:nil message:nil preferredStyle:UIAlertControllerStyleActionSheet];
controller.modalPresentationStyle = UIModalPresentationPopover;
controller.popoverPresentationController.barButtonItem = (UIBarButtonItem *)sender;

... setup the UIAlertController ... 

[controller view]; // <--- Add to silence the warning.

[self presentViewController:controller animated:YES completion:nil];

facebook: permanent Page Access Token?

In addition to the recommended steps in the Vlasec answer, you can use:

  • Graph API explorer to make the queries, e.g. /{pageId}?fields=access_token&access_token=THE_ACCESS_TOKEN_PROVIDED_BY_GRAPH_EXPLORER
  • Access Token Debugger to get information about the access token.

Reading from memory stream to string

If you'd checked the results of stream.Read, you'd have seen that it hadn't read anything - because you haven't rewound the stream. (You could do this with stream.Position = 0;.) However, it's easier to just call ToArray:

settingsString = LocalEncoding.GetString(stream.ToArray());

(You'll need to change the type of stream from Stream to MemoryStream, but that's okay as it's in the same method where you create it.)

Alternatively - and even more simply - just use StringWriter instead of StreamWriter. You'll need to create a subclass if you want to use UTF-8 instead of UTF-16, but that's pretty easy. See this answer for an example.

I'm concerned by the way you're just catching Exception and assuming that it means something harmless, by the way - without even logging anything. Note that using statements are generally cleaner than writing explicit finally blocks.

Procedure expects parameter which was not supplied

I came across this error today when null values were passed to my stored procedure's parameters. I was able easily fix by altering the stored procedure by adding default value = null.

How do I grant read access for a user to a database in SQL Server?

This is a two-step process:

  1. you need to create a login to SQL Server for that user, based on its Windows account

    CREATE LOGIN [<domainName>\<loginName>] FROM WINDOWS;
    
  2. you need to grant this login permission to access a database:

    USE (your database)
    CREATE USER (username) FOR LOGIN (your login name)
    

Once you have that user in your database, you can give it any rights you want, e.g. you could assign it the db_datareader database role to read all tables.

USE (your database)
EXEC sp_addrolemember 'db_datareader', '(your user name)'

Convert NaN to 0 in javascript

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    var i = [NaN, 1,2,3];

    var j = i.map(i =>{ return isNaN(i) ? 0 : i});
    
    console.log(j)
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jQuery AJAX submit form

There's also the submit event, which can be triggered like this $("#form_id").submit(). You'd use this method if the form is well represented in HTML already. You'd just read in the page, populate the form inputs with stuff, then call .submit(). It'll use the method and action defined in the form's declaration, so you don't need to copy it into your javascript.

examples

String formatting: % vs. .format vs. string literal

But one thing is that also if you have nested curly-braces, won't work for format but % will work.

Example:

>>> '{{0}, {1}}'.format(1,2)
Traceback (most recent call last):
  File "<pyshell#3>", line 1, in <module>
    '{{0}, {1}}'.format(1,2)
ValueError: Single '}' encountered in format string
>>> '{%s, %s}'%(1,2)
'{1, 2}'
>>> 

How to remove leading zeros from alphanumeric text?

Use this:

String x = "00123".replaceAll("^0*", ""); // -> 123

E11000 duplicate key error index in mongodb mongoose

Drop you database, then it will work.

You can perform the following steps to drop your database

step 1 : Go to mongodb installation directory, default dir is "C:\Program Files\MongoDB\Server\4.2\bin"

step 2 : Start mongod.exe directly or using command prompt and minimize it.

step 3 : Start mongo.exe directly or using command prompt and run the following command

i) use yourDatabaseName (use show databases if you don't remember database name)

ii) db.dropDatabase()

This will remove your database. Now you can insert your data, it won't show error, it will automatically add database and collection.

Split string into array of character strings

If the original string contains supplementary Unicode characters, then split() would not work, as it splits these characters into surrogate pairs. To correctly handle these special characters, a code like this works:

String[] chars = new String[stringToSplit.codePointCount(0, stringToSplit.length())];
for (int i = 0, j = 0; i < stringToSplit.length(); j++) {
    int cp = stringToSplit.codePointAt(i);
    char c[] = Character.toChars(cp);
    chars[j] = new String(c);
    i += Character.charCount(cp);
}

How to start Apache and MySQL automatically when Windows 8 comes up

You can do it via cmd.

For Apache

Open cmd in administrator mode. Change directory to C:/xampp/apache/bin. Run the command as httpd.exe -k install. Your Apache server service will be installed. You can start it from services.

For MySQL

Change directory to C:/xampp/mysql/bin. Run the command as mysqld --install. Your MySQL service will be installed. You can start it from services.

Note: Make sure the selected Apache and MySQL services are set to start automatically.

You're done. There isn't any need to launch the XAMPP control panel

Maintain model of scope when changing between views in AngularJS

Angular doesn't really provide what you are looking for out of the box. What i would do to accomplish what you're after is use the following add ons

UI Router & UI Router Extras

These two will provide you with state based routing and sticky states, you can tab between states and all information will be saved as the scope "stays alive" so to speak.

Check the documentation on both as it's pretty straight forward, ui router extras also has a good demonstration of how sticky states works.

What does .shape[] do in "for i in range(Y.shape[0])"?

In python, Suppose you have loaded up the data in some variable train:

train = pandas.read_csv('file_name')
>>> train
train([[ 1.,  2.,  3.],
        [ 5.,  1.,  2.]],)

I want to check what are the dimensions of the 'file_name'. I have stored the file in train

>>>train.shape
(2,3)
>>>train.shape[0]              # will display number of rows
2
>>>train.shape[1]              # will display number of columns
3

php $_POST array empty upon form submission

In addition to MRMage's post:

I had to set this variable to solve the problem that some $_POST variables (with an large array > 1000 items) disappeared:

suhosin.request.max_vars = 2500

"request", not "post" was the solution...

How to get file size in Java

Use the length() method in the File class. From the javadocs:

Returns the length of the file denoted by this abstract pathname. The return value is unspecified if this pathname denotes a directory.

UPDATED Nowadays we should use the Files.size() method:

Paths path = Paths.get("/path/to/file");
long size = Files.size(path);

For the second part of the question, straight from File's javadocs:

  • getUsableSpace() Returns the number of bytes available to this virtual machine on the partition named by this abstract pathname

  • getTotalSpace() Returns the size of the partition named by this abstract pathname

  • getFreeSpace() Returns the number of unallocated bytes in the partition named by this abstract path name

Connection Strings for Entity Framework

Silverlight applications do not have direct access to machine.config.

html/css buttons that scroll down to different div sections on a webpage

try this:

<input type="button" onClick="document.getElementById('middle').scrollIntoView();" />

SSIS Connection not found in package

For package developed in Visual Studio 2015, I found i must supply a value for the parameter (which would be the case when you deploy or run on different server) which sets the connection manager's connection string instead of using the design time value. This will suppress the error message. I think this could be a bug.

dtexec /project c:\mypath\ETL.ispac /package mypackage.dtsx /SET \Package.Variables[$Project::myParameterName];"myValueForTheParameter"

I tested this without or without parameterize the connection string, which is at the project level. The result was the same: i.e. I have to set the value for the parameter even thought it was not used.

size of NumPy array

This is called the "shape" in NumPy, and can be requested via the .shape attribute:

>>> a = zeros((2, 5))
>>> a.shape
(2, 5)

If you prefer a function, you could also use numpy.shape(a).

Reloading the page gives wrong GET request with AngularJS HTML5 mode

I am using apache (xampp) on my dev environment and apache on the production, add:

errorDocument 404 /index.html

to the .htaccess solve for me this issue.

Shell Script — Get all files modified after <date>

This will work for some number of files. You want to include "-print0" and "xargs -0" in case any of the paths have spaces in them. This example looks for files modified in the last 7 days. To find those modified before the last 7 days, use "+7".

find . -mtime -7 -print0 | xargs -0 tar -cjf /foo/archive.tar.bz2

As this page warns, xargs can cause the tar command to be executed multiple times if there are a lot of arguments, and the "-c" flag could cause problems. In that case, you would want this:

find . -mtime -7 -print0 | xargs -0 tar -rf /foo/archive.tar

You can't update a zipped tar archive with tar, so you would have to bzip2 or gzip it in a second step.

Test if number is odd or even

While all of the answers are good and correct, simple solution in one line is:

$check = 9;

either:

echo ($check & 1 ? 'Odd' : 'Even');

or:

echo ($check % 2 ? 'Odd' : 'Even');

works very well.

How to implement infinity in Java?

I'm a beginner in Java... I found another implementation for the infinity in the Java documentation, for the boolean and double types. https://docs.oracle.com/javase/specs/jls/se7/html/jls-4.html#jls-4.2.3

Positive zero and negative zero compare equal; thus the result of the expression 0.0==-0.0 is true and the result of 0.0>-0.0 is false. But other operations can distinguish positive and negative zero; for example, 1.0/0.0 has the value positive infinity, while the value of 1.0/-0.0 is negative infinity.

It looks ugly, but it works.

public class Main {

    public static void main(String[] args) {
        System.out.println(1.0/0.0);
        System.out.println(-1.0/0.0);
    }

}

Formatting DataBinder.Eval data

Thanks to all. I had been stuck on standard format strings for some time. I also used a custom function in VB.

Mark Up:-

<asp:Label ID="Label3" runat="server" text='<%# Formatlabel(DataBinder.Eval(Container.DataItem, "psWages1D")) %>'/>

Code behind:-

Public Function fLabel(ByVal tval) As String
   fLabel = tval.ToString("#,##0.00%;(#,##0.00%);Zero")
End Function

npm - how to show the latest version of a package

As of October 2014:

npm view illustration

For latest remote version:

npm view <module_name> version  

Note, version is singular.

If you'd like to see all available (remote) versions, then do:

npm view <module_name> versions

Note, versions is plural. This will give you the full listing of versions to choose from.

To get the version you actually have locally you could use:

npm list --depth=0 | grep <module_name>

Note, even with package.json declaring your versions, the installed version might actually differ slightly - for instance if tilda was used in the version declaration

Should work across NPM versions 1.3.x, 1.4.x, 2.x and 3.x