Programs & Examples On #Insight

Insight is a graphical front-end for GDB, the GNU Debugger, developed by RedHat. Its development has been stopped in July 2009 with the version 6.8 of GDB.

Error - Android resource linking failed (AAPT2 27.0.3 Daemon #0)

There should be some error in resource files. It mean is there may be miss typed value of attributes. Go through the resource files and correct these value and enjoy the work.

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

Have you tried:

pip install <package>

or

conda install -c conda-forge <package>

find_spec_for_exe': can't find gem bundler (>= 0.a) (Gem::GemNotFoundException)

The reason is your current ruby environment, you got a different version of bundler with the version in Gemfile.lock.

  • Safe way, install bundler with the same version in Gemfile.lock, this won't break anything if there is some incampatibly thing happened.
  • Hard way, just remove Gemfile.lock, and run bundle install.

How to generate components in a specific folder with Angular CLI?

more shorter code to generate component: ng g c component-name
to specify its location: ng g c specific-folder/component-name


Additional info
more shorter code to generate directive: ng g d directive-name
to specify its location: ng g d specific-folder/directive-name

Jest spyOn function called

You were almost done without any changes besides how you spyOn. When you use the spy, you have two options: spyOn the App.prototype, or component component.instance().

const spy = jest.spyOn(Class.prototype, "method")

The order of attaching the spy on the class prototype and rendering (shallow rendering) your instance is important.

const spy = jest.spyOn(App.prototype, "myClickFn");
const instance = shallow(<App />);

The App.prototype bit on the first line there are what you needed to make things work. A JavaScript class doesn't have any of its methods until you instantiate it with new MyClass(), or you dip into the MyClass.prototype. For your particular question, you just needed to spy on the App.prototype method myClickFn.

jest.spyOn(component.instance(), "method")

const component = shallow(<App />);
const spy = jest.spyOn(component.instance(), "myClickFn");

This method requires a shallow/render/mount instance of a React.Component to be available. Essentially spyOn is just looking for something to hijack and shove into a jest.fn(). It could be:

A plain object:

const obj = {a: x => (true)};
const spy = jest.spyOn(obj, "a");

A class:

class Foo {
    bar() {}
}

const nope = jest.spyOn(Foo, "bar");
// THROWS ERROR. Foo has no "bar" method.
// Only an instance of Foo has "bar".
const fooSpy = jest.spyOn(Foo.prototype, "bar");
// Any call to "bar" will trigger this spy; prototype or instance

const fooInstance = new Foo();
const fooInstanceSpy = jest.spyOn(fooInstance, "bar");
// Any call fooInstance makes to "bar" will trigger this spy.

Or a React.Component instance:

const component = shallow(<App />);
/*
component.instance()
-> {myClickFn: f(), render: f(), ...etc}
*/
const spy = jest.spyOn(component.instance(), "myClickFn");

Or a React.Component.prototype:

/*
App.prototype
-> {myClickFn: f(), render: f(), ...etc}
*/
const spy = jest.spyOn(App.prototype, "myClickFn");
// Any call to "myClickFn" from any instance of App will trigger this spy.

I've used and seen both methods. When I have a beforeEach() or beforeAll() block, I might go with the first approach. If I just need a quick spy, I'll use the second. Just mind the order of attaching the spy.

EDIT: If you want to check the side effects of your myClickFn you can just invoke it in a separate test.

const app = shallow(<App />);
app.instance().myClickFn()
/*
Now assert your function does what it is supposed to do...
eg.
expect(app.state("foo")).toEqual("bar");
*/

EDIT: Here is an example of using a functional component. Keep in mind that any methods scoped within your functional component are not available for spying. You would be spying on function props passed into your functional component and testing the invocation of those. This example explores the use of jest.fn() as opposed to jest.spyOn, both of which share the mock function API. While it does not answer the original question, it still provides insight on other techniques that could suit cases indirectly related to the question.

function Component({ myClickFn, items }) {
   const handleClick = (id) => {
       return () => myClickFn(id);
   };
   return (<>
       {items.map(({id, name}) => (
           <div key={id} onClick={handleClick(id)}>{name}</div>
       ))}
   </>);
}

const props = { myClickFn: jest.fn(), items: [/*...{id, name}*/] };
const component = render(<Component {...props} />);
// Do stuff to fire a click event
expect(props.myClickFn).toHaveBeenCalledWith(/*whatever*/);

Getting permission denied (public key) on gitlab

There seem to be differences between the two ways to access a git repository i.e. using either SSH or HTTPS. For me, I encountered the error because I was trying to push my local repository using SSH.

The problem can simply be solved by clicking the clone button on the landing page of your project and the copying the HTTPS link and replacing it to the SSH link appearing with the format "git@gitlab...".

Deep-Learning Nan loss reasons

If using integers as targets, makes sure they aren't symmetrical at 0.

I.e., don't use classes -1, 0, 1. Use instead 0, 1, 2.

How do I access Configuration in any class in ASP.NET Core?

I looked into the options pattern sample and saw this:

public class Startup
{
    public Startup(IConfiguration config)
    {
        // Configuration from appsettings.json has already been loaded by
        // CreateDefaultBuilder on WebHost in Program.cs. Use DI to load
        // the configuration into the Configuration property.
        Configuration = config;
    }
...
}

When adding Iconfiguration in the constructor of my class, I could access the configuration options through DI.

Example:

public class MyClass{

    private Iconfiguration _config;

    public MyClass(Iconfiguration config){
        _config = config;
    }

    ... // access _config["myAppSetting"] anywhere in this class
}

Body of Http.DELETE request in Angular2

You are actually able to fool Angular2 HTTP into sending a body with a DELETE by using the request method. This is how:

let body = {
    target: targetId,
    subset: "fruits",
    reason: "rotten"
};

let options = new RequestOptionsArgs({ 
    body: body,
    method: RequestMethod.Delete
  });

this.http.request('http://testAPI:3000/stuff', options)
    .subscribe((ok)=>{console.log(ok)});

Note, you will have to set the request method in the RequestOptionsArgs and not in http.request's alternative first parameter Request. That for some reason yields the same result as using http.delete

I hope this helps and that I am not to late. I think the angular guys are wrong here to not allow a body to be passed with delete, even though it is discouraged.

What is the best way to access redux store outside a react component?

An easy way to have access to the token, is to put the token in the LocalStorage or the AsyncStorage with React Native.

Below an example with a React Native project

authReducer.js

import { AsyncStorage } from 'react-native';
...
const auth = (state = initialState, action) => {
  switch (action.type) {
    case SUCCESS_LOGIN:
      AsyncStorage.setItem('token', action.payload.token);
      return {
        ...state,
        ...action.payload,
      };
    case REQUEST_LOGOUT:
      AsyncStorage.removeItem('token');
      return {};
    default:
      return state;
  }
};
...

and api.js

import axios from 'axios';
import { AsyncStorage } from 'react-native';

const defaultHeaders = {
  'Content-Type': 'application/json',
};

const config = {
  ...
};

const request = axios.create(config);

const protectedRequest = options => {
  return AsyncStorage.getItem('token').then(token => {
    if (token) {
      return request({
        headers: {
          ...defaultHeaders,
          Authorization: `Bearer ${token}`,
        },
        ...options,
      });
    }
    return new Error('NO_TOKEN_SET');
  });
};

export { request, protectedRequest };

For web you can use Window.localStorage instead of AsyncStorage

How to get rid of underline for Link component of React Router?

Working for me, just add className="nav-link" and activeStyle{{textDecoration:'underline'}}

<NavLink className="nav-link" to="/" exact activeStyle= 
  {{textDecoration:'underline'}}>My Record</NavLink>

What are the pros and cons of parquet format compared to other formats?

I think the main difference I can describe relates to record oriented vs. column oriented formats. Record oriented formats are what we're all used to -- text files, delimited formats like CSV, TSV. AVRO is slightly cooler than those because it can change schema over time, e.g. adding or removing columns from a record. Other tricks of various formats (especially including compression) involve whether a format can be split -- that is, can you read a block of records from anywhere in the dataset and still know it's schema? But here's more detail on columnar formats like Parquet.

Parquet, and other columnar formats handle a common Hadoop situation very efficiently. It is common to have tables (datasets) having many more columns than you would expect in a well-designed relational database -- a hundred or two hundred columns is not unusual. This is so because we often use Hadoop as a place to denormalize data from relational formats -- yes, you get lots of repeated values and many tables all flattened into a single one. But it becomes much easier to query since all the joins are worked out. There are other advantages such as retaining state-in-time data. So anyway it's common to have a boatload of columns in a table.

Let's say there are 132 columns, and some of them are really long text fields, each different column one following the other and use up maybe 10K per record.

While querying these tables is easy with SQL standpoint, it's common that you'll want to get some range of records based on only a few of those hundred-plus columns. For example, you might want all of the records in February and March for customers with sales > $500.

To do this in a row format the query would need to scan every record of the dataset. Read the first row, parse the record into fields (columns) and get the date and sales columns, include it in your result if it satisfies the condition. Repeat. If you have 10 years (120 months) of history, you're reading every single record just to find 2 of those months. Of course this is a great opportunity to use a partition on year and month, but even so, you're reading and parsing 10K of each record/row for those two months just to find whether the customer's sales are > $500.

In a columnar format, each column (field) of a record is stored with others of its kind, spread all over many different blocks on the disk -- columns for year together, columns for month together, columns for customer employee handbook (or other long text), and all the others that make those records so huge all in their own separate place on the disk, and of course columns for sales together. Well heck, date and months are numbers, and so are sales -- they are just a few bytes. Wouldn't it be great if we only had to read a few bytes for each record to determine which records matched our query? Columnar storage to the rescue!

Even without partitions, scanning the small fields needed to satisfy our query is super-fast -- they are all in order by record, and all the same size, so the disk seeks over much less data checking for included records. No need to read through that employee handbook and other long text fields -- just ignore them. So, by grouping columns with each other, instead of rows, you can almost always scan less data. Win!

But wait, it gets better. If your query only needed to know those values and a few more (let's say 10 of the 132 columns) and didn't care about that employee handbook column, once it had picked the right records to return, it would now only have to go back to the 10 columns it needed to render the results, ignoring the other 122 of the 132 in our dataset. Again, we skip a lot of reading.

(Note: for this reason, columnar formats are a lousy choice when doing straight transformations, for example, if you're joining all of two tables into one big(ger) result set that you're saving as a new table, the sources are going to get scanned completely anyway, so there's not a lot of benefit in read performance, and because columnar formats need to remember more about the where stuff is, they use more memory than a similar row format).

One more benefit of columnar: data is spread around. To get a single record, you can have 132 workers each read (and write) data from/to 132 different places on 132 blocks of data. Yay for parallelization!

And now for the clincher: compression algorithms work much better when it can find repeating patterns. You could compress AABBBBBBCCCCCCCCCCCCCCCC as 2A6B16C but ABCABCBCBCBCCCCCCCCCCCCCC wouldn't get as small (well, actually, in this case it would, but trust me :-) ). So once again, less reading. And writing too.

So we read a lot less data to answer common queries, it's potentially faster to read and write in parallel, and compression tends to work much better.

Columnar is great when your input side is large, and your output is a filtered subset: from big to little is great. Not as beneficial when the input and outputs are about the same.

But in our case, Impala took our old Hive queries that ran in 5, 10, 20 or 30 minutes, and finished most in a few seconds or a minute.

Hope this helps answer at least part of your question!

npm install error - unable to get local issuer certificate

There is an issue discussed here which talks about using ca files, but it's a bit beyond my understanding and I'm unsure what to do about it.

This isn't too difficult once you know how! For Windows:

Using Chrome go to the root URL NPM is complaining about (so https://raw.githubusercontent.com in your case). Open up dev tools and go to Security-> View Certificate. Check Certification path and make sure your at the top level certificate, if not open that one. Now go to "Details" and export the cert with "Copy to File...".

You need to convert this from DER to PEM. There are several ways to do this, but the easiest way I found was an online tool which should be easy to find with relevant keywords.

Now if you open the key with your favorite text editor you should see

-----BEGIN CERTIFICATE----- 

yourkey

-----END CERTIFICATE-----

This is the format you need. You can do this for as many keys as you need, and combine them all into one file. I had to do github and the npm registry keys in my case.

Now just edit your .npmrc to point to the file containing your keys like so

cafile=C:\workspace\rootCerts.crt

I have personally found this to perform significantly better behind our corporate proxy as opposed to the strict-ssl option. YMMV.

REST API - file (ie images) processing - best practices

There are several decisions to make:

  1. The first about resource path:

    • Model the image as a resource on its own:

      • Nested in user (/user/:id/image): the relationship between the user and the image is made implicitly

      • In the root path (/image):

        • The client is held responsible for establishing the relationship between the image and the user, or;

        • If a security context is being provided with the POST request used to create an image, the server can implicitly establish a relationship between the authenticated user and the image.

    • Embed the image as part of the user

  2. The second decision is about how to represent the image resource:

    • As Base 64 encoded JSON payload
    • As a multipart payload

This would be my decision track:

  • I usually favor design over performance unless there is a strong case for it. It makes the system more maintainable and can be more easily understood by integrators.
  • So my first thought is to go for a Base64 representation of the image resource because it lets you keep everything JSON. If you chose this option you can model the resource path as you like.
    • If the relationship between user and image is 1 to 1 I'd favor to model the image as an attribute specially if both data sets are updated at the same time. In any other case you can freely choose to model the image either as an attribute, updating the it via PUT or PATCH, or as a separate resource.
  • If you choose multipart payload I'd feel compelled to model the image as a resource on is own, so that other resources, in our case, the user resource, is not impacted by the decision of using a binary representation for the image.

Then comes the question: Is there any performance impact about choosing base64 vs multipart?. We could think that exchanging data in multipart format should be more efficient. But this article shows how little do both representations differ in terms of size.

My choice Base64:

  • Consistent design decision
  • Negligible performance impact
  • As browsers understand data URIs (base64 encoded images), there is no need to transform these if the client is a browser
  • I won't cast a vote on whether to have it as an attribute or standalone resource, it depends on your problem domain (which I don't know) and your personal preference.

Error: Execution failed for task ':app:clean'. Unable to delete file

My Solution for this was very very simple ( if you are using Windows). 1- Close Android Studio. 2- Run Android Studio as Administrator. 3- That is it.

Detecting user leaving page with react-router

For react-router 2.4.0+

NOTE: It is advisable to migrate all your code to the latest react-router to get all the new goodies.

As recommended in the react-router documentation:

One should use the withRouter higher order component:

We think this new HoC is nicer and easier, and will be using it in documentation and examples, but it is not a hard requirement to switch.

As an ES6 example from the documentation:

import React from 'react'
import { withRouter } from 'react-router'

const Page = React.createClass({

  componentDidMount() {
    this.props.router.setRouteLeaveHook(this.props.route, () => {
      if (this.state.unsaved)
        return 'You have unsaved information, are you sure you want to leave this page?'
    })
  }

  render() {
    return <div>Stuff</div>
  }

})

export default withRouter(Page)

How to load CSS Asynchronously

Use rel="preload" to make it download independently, then use onload="this.rel='stylesheet'" to apply it to the stylesheet (as="style" is necessary to apply it to stylesheet else the onload won't work)

<link rel="preload" as="style" type="text/css" href="mystyles.css" onload="this.rel='stylesheet'">

PageSpeed Insights 99/100 because of Google Analytics - How can I cache GA?

I wouldn't worry about it. Don't put it on your own server, it sounds like this is an issue with Google, but as good as it gets. Putting the file on your own server will create many new problems.

They probably need the file to get called every time rather than getting it from the client's cache, since that way you wouldn't count the visits.

If you have a problem to feel fine with that, run the Google insights URL on Google insights itself, have a laugh, relax and get on with your work.

Google Chrome forcing download of "f.txt" file

Seems related to https://groups.google.com/forum/#!msg/google-caja-discuss/ite6K5c8mqs/Ayqw72XJ9G8J.

The so-called "Rosetta Flash" vulnerability is that allowing arbitrary yet identifier-like text at the beginning of a JSONP response is sufficient for it to be interpreted as a Flash file executing in that origin. See for more information: http://miki.it/blog/2014/7/8/abusing-jsonp-with-rosetta-flash/

JSONP responses from the proxy servlet now: * are prefixed with "/**/", which still allows them to execute as JSONP but removes requester control over the first bytes of the response. * have the response header Content-Disposition: attachment.

Touch move getting stuck Ignored attempt to cancel a touchmove

I had this problem and all I had to do is return true from touchend and the warning went away.

File size exceeds configured limit (2560000), code insight features not available

Changing the above options form Help menu didn't work for me. You have edit idea.properties file and change to some large no.

MAC: /Applications/<Android studio>.app/Contents/bin[Open App contents] 

Idea.max.intellisense.filesize=999999 

WINDOWS: IDE_HOME\bin\idea.properties

Peak signal detection in realtime timeseries data

Here is a Groovy (Java) implementation of the smoothed z-score algorithm (see answer above).

/**
 * "Smoothed zero-score alogrithm" shamelessly copied from https://stackoverflow.com/a/22640362/6029703
 *  Uses a rolling mean and a rolling deviation (separate) to identify peaks in a vector
 *
 * @param y - The input vector to analyze
 * @param lag - The lag of the moving window (i.e. how big the window is)
 * @param threshold - The z-score at which the algorithm signals (i.e. how many standard deviations away from the moving mean a peak (or signal) is)
 * @param influence - The influence (between 0 and 1) of new signals on the mean and standard deviation (how much a peak (or signal) should affect other values near it)
 * @return - The calculated averages (avgFilter) and deviations (stdFilter), and the signals (signals)
 */

public HashMap<String, List<Object>> thresholdingAlgo(List<Double> y, Long lag, Double threshold, Double influence) {
    //init stats instance
    SummaryStatistics stats = new SummaryStatistics()

    //the results (peaks, 1 or -1) of our algorithm
    List<Integer> signals = new ArrayList<Integer>(Collections.nCopies(y.size(), 0))
    //filter out the signals (peaks) from our original list (using influence arg)
    List<Double> filteredY = new ArrayList<Double>(y)
    //the current average of the rolling window
    List<Double> avgFilter = new ArrayList<Double>(Collections.nCopies(y.size(), 0.0d))
    //the current standard deviation of the rolling window
    List<Double> stdFilter = new ArrayList<Double>(Collections.nCopies(y.size(), 0.0d))
    //init avgFilter and stdFilter
    (0..lag-1).each { stats.addValue(y[it as int]) }
    avgFilter[lag - 1 as int] = stats.getMean()
    stdFilter[lag - 1 as int] = Math.sqrt(stats.getPopulationVariance()) //getStandardDeviation() uses sample variance (not what we want)
    stats.clear()
    //loop input starting at end of rolling window
    (lag..y.size()-1).each { i ->
        //if the distance between the current value and average is enough standard deviations (threshold) away
        if (Math.abs((y[i as int] - avgFilter[i - 1 as int]) as Double) > threshold * stdFilter[i - 1 as int]) {
            //this is a signal (i.e. peak), determine if it is a positive or negative signal
            signals[i as int] = (y[i as int] > avgFilter[i - 1 as int]) ? 1 : -1
            //filter this signal out using influence
            filteredY[i as int] = (influence * y[i as int]) + ((1-influence) * filteredY[i - 1 as int])
        } else {
            //ensure this signal remains a zero
            signals[i as int] = 0
            //ensure this value is not filtered
            filteredY[i as int] = y[i as int]
        }
        //update rolling average and deviation
        (i - lag..i-1).each { stats.addValue(filteredY[it as int] as Double) }
        avgFilter[i as int] = stats.getMean()
        stdFilter[i as int] = Math.sqrt(stats.getPopulationVariance()) //getStandardDeviation() uses sample variance (not what we want)
        stats.clear()
    }

    return [
        signals  : signals,
        avgFilter: avgFilter,
        stdFilter: stdFilter
    ]
}

Below is a test on the same dataset that yields the same results as the above Python / numpy implementation.

    // Data
    def y = [1d, 1d, 1.1d, 1d, 0.9d, 1d, 1d, 1.1d, 1d, 0.9d, 1d, 1.1d, 1d, 1d, 0.9d, 1d, 1d, 1.1d, 1d, 1d,
         1d, 1d, 1.1d, 0.9d, 1d, 1.1d, 1d, 1d, 0.9d, 1d, 1.1d, 1d, 1d, 1.1d, 1d, 0.8d, 0.9d, 1d, 1.2d, 0.9d, 1d,
         1d, 1.1d, 1.2d, 1d, 1.5d, 1d, 3d, 2d, 5d, 3d, 2d, 1d, 1d, 1d, 0.9d, 1d,
         1d, 3d, 2.6d, 4d, 3d, 3.2d, 2d, 1d, 1d, 0.8d, 4d, 4d, 2d, 2.5d, 1d, 1d, 1d]

    // Settings
    def lag = 30
    def threshold = 5
    def influence = 0


    def thresholdingResults = thresholdingAlgo((List<Double>) y, (Long) lag, (Double) threshold, (Double) influence)

    println y.size()
    println thresholdingResults.signals.size()
    println thresholdingResults.signals

    thresholdingResults.signals.eachWithIndex { x, idx ->
        if (x) {
            println y[idx]
        }
    }

How to download a file from my server using SSH (using PuTTY on Windows)

try this scp -r -P2222 [email protected]:/home2/kwazy/www/utrecht-connected.nl /Desktop

Another easier option if you're going to be pulling files left and right is to just use an SFTP client like WinSCP. Then you're not typing out 100 characters every time you want to pull something, just drag and drop.

Edit: Just noticed /Desktop probably isn't where you're looking to download the file to. Should be something like C:\Users\you\Desktop

git: diff between file in local repo and origin

I tried a couple of solution but I thing easy way like this (you are in the local folder):

#!/bin/bash
git fetch

var_local=`cat .git/refs/heads/master`
var_remote=`git log origin/master -1 | head -n1 | cut -d" " -f2`

if [ "$var_remote" = "$var_local" ]; then
    echo "Strings are equal." #1
else
    echo "Strings are not equal." #0 if you want
fi

Then you did compare local git and remote git last commit number....

Why is this error, 'Sequence contains no elements', happening?

In the following line.

temp.Response = db.Responses.Where(y => y.ResponseId.Equals(item.ResponseId)).First();

You are calling First but the collection returned from db.Responses.Where is empty.

The program can't start because MSVCR110.dll is missing from your computer

I was getting a similar issue from the Apache Lounge 32 bit version. After downloading the 64 bit version, the issue was resolved.

Here is an excellent video explain the steps involved: https://www.youtube.com/watch?v=17qhikHv5hY

Bootstrap 3 Slide in Menu / Navbar on Mobile

Bootstrap 4

Create a responsive navbar sidebar "drawer" in Bootstrap 4?
Bootstrap horizontal menu collapse to sidemenu

Bootstrap 3

I think what you're looking for is generally known as an "off-canvas" layout. Here is the standard off-canvas example from the official Bootstrap docs: http://getbootstrap.com/examples/offcanvas/

The "official" example uses a right-side sidebar the toggle off and on separately from the top navbar menu. I also found these off-canvas variations that slide in from the left and may be closer to what you're looking for..

http://www.bootstrapzero.com/bootstrap-template/off-canvas-sidebar http://www.bootstrapzero.com/bootstrap-template/facebook

Laravel Eloquent get results grouped by days

You can use Carbon (integrated in Laravel)

// Carbon
use Carbon\Carbon;   
$visitorTraffic = PageView::select('id', 'title', 'created_at')
    ->get()
    ->groupBy(function($date) {
        return Carbon::parse($date->created_at)->format('Y'); // grouping by years
        //return Carbon::parse($date->created_at)->format('m'); // grouping by months
    });

JavaFX "Location is required." even though it is in the same package

If you look at the docs [1], you see that the load() method can take a URL:

load(URL location)

So if you're running Java 7 or newer, you can load the FXML file like this:

URL url = Paths.get("./src/main/resources/fxml/Fxml.fxml").toUri().toURL();
Parent root = FXMLLoder.load(url);

This example is from a Maven project, which is why the FXML file is in the resources folder.

[1] https://docs.oracle.com/javase/8/javafx/api/javafx/fxml/FXMLLoader.htm

How to connect to mysql with laravel?

In Laravel 5, there is a .env file,

It looks like

APP_ENV=local
APP_DEBUG=true
APP_KEY=YOUR_API_KEY

DB_HOST=YOUR_HOST
DB_DATABASE=YOUR_DATABASE
DB_USERNAME=YOUR_USERNAME
DB_PASSWORD=YOUR_PASSWORD

CACHE_DRIVER=file
SESSION_DRIVER=file
QUEUE_DRIVER=sync

MAIL_DRIVER=smtp
MAIL_HOST=mailtrap.io
MAIL_PORT=2525
MAIL_USERNAME=null
MAIL_PASSWORD=null

Edit that .env There is .env.sample is there , try to create from that if no such .env file found.

Insert Data Into Temp Table with Query

Fastest way to do this is using "SELECT INTO" command e.g.

SELECT * INTO #TempTableName
FROM....

This will create a new table, you don't have to create it in advance.

Can you split a stream into two streams?

A collector can be used for this.

  • For two categories, use Collectors.partitioningBy() factory.

This will create a Map from Boolean to List, and put items in one or the other list based on a Predicate.

Note: Since the stream needs to be consumed whole, this can't work on infinite streams. And because the stream is consumed anyway, this method simply puts them in Lists instead of making a new stream-with-memory. You can always stream those lists if you require streams as output.

Also, no need for the iterator, not even in the heads-only example you provided.

  • Binary splitting looks like this:
Random r = new Random();

Map<Boolean, List<String>> groups = stream
    .collect(Collectors.partitioningBy(x -> r.nextBoolean()));

System.out.println(groups.get(false).size());
System.out.println(groups.get(true).size());
  • For more categories, use a Collectors.groupingBy() factory.
Map<Object, List<String>> groups = stream
    .collect(Collectors.groupingBy(x -> r.nextInt(3)));
System.out.println(groups.get(0).size());
System.out.println(groups.get(1).size());
System.out.println(groups.get(2).size());

In case the streams are not Stream, but one of the primitive streams like IntStream, then this .collect(Collectors) method is not available. You'll have to do it the manual way without a collector factory. It's implementation looks like this:

[Example 2.0 since 2020-04-16]

    IntStream    intStream = IntStream.iterate(0, i -> i + 1).limit(100000).parallel();
    IntPredicate predicate = ignored -> r.nextBoolean();

    Map<Boolean, List<Integer>> groups = intStream.collect(
            () -> Map.of(false, new ArrayList<>(100000),
                         true , new ArrayList<>(100000)),
            (map, value) -> map.get(predicate.test(value)).add(value),
            (map1, map2) -> {
                map1.get(false).addAll(map2.get(false));
                map1.get(true ).addAll(map2.get(true ));
            });

In this example I initialize the ArrayLists with the full size of the initial collection (if this is known at all). This prevents resize events even in the worst-case scenario, but can potentially gobble up 2*N*T space (N = initial number of elements, T = number of threads). To trade-off space for speed, you can leave it out or use your best educated guess, like the expected highest number of elements in one partition (typically just over N/2 for a balanced split).

I hope I don't offend anyone by using a Java 9 method. For the Java 8 version, look at the edit history.

Bootstrap 3 : Vertically Center Navigation Links when Logo Increasing The Height of Navbar

Use the Bootstrap Customizer to generate a version of Bootstrap that has a taller navbar. The value you want to change is @navbar-height in the Navbar section.

Inspect your current implementation to see how tall your navbar is with the 50px brand image, and use that calculated height in the Customizer.

Eclipse gives “Java was started but returned exit code 13”

When I uninstalled Java 8 it worked fine.

Name does not exist in the current context

I also faced a similar issue. The reason was that I had the changes done in the .aspx page but not the designer page and hence I got the mentioned error. When the reference was created in the designer page I was able to build the solution.

"Data too long for column" - why?

There is an hard limit on how much data can be stored in a single row of a mysql table, regardless of the number of columns or the individual column length.

As stated in the OFFICIAL DOCUMENTATION

The maximum row size constrains the number (and possibly size) of columns because the total length of all columns cannot exceed this size. For example, utf8 characters require up to three bytes per character, so for a CHAR(255) CHARACTER SET utf8 column, the server must allocate 255 × 3 = 765 bytes per value. Consequently, a table cannot contain more than 65,535 / 765 = 85 such columns.

Storage for variable-length columns includes length bytes, which are assessed against the row size. For example, a VARCHAR(255) CHARACTER SET utf8 column takes two bytes to store the length of the value, so each value can take up to 767 bytes.

Here you can find INNODB TABLES LIMITATIONS

"Eliminate render-blocking CSS in above-the-fold content"

Please have a look on the following page https://varvy.com/pagespeed/render-blocking-css.html . This helped me to get rid of "Render Blocking CSS". I used the following code in order to remove "Render Blocking CSS". Now in google page speed insight I am not getting issue related with render blocking css.

<!-- loadCSS -->
<script src="https://cdn.rawgit.com/filamentgroup/loadCSS/6b637fe0/src/cssrelpreload.js"></script>
<script src="https://cdn.rawgit.com/filamentgroup/loadCSS/6b637fe0/src/loadCSS.js"></script>
<script src="https://cdn.rawgit.com/filamentgroup/loadCSS/6b637fe0/src/onloadCSS.js"></script>
<script>
      /*!
      loadCSS: load a CSS file asynchronously.
      */
      function loadCSS(href){
        var ss = window.document.createElement('link'),
            ref = window.document.getElementsByTagName('head')[0];

        ss.rel = 'stylesheet';
        ss.href = href;

        // temporarily, set media to something non-matching to ensure it'll
        // fetch without blocking render
        ss.media = 'only x';

        ref.parentNode.insertBefore(ss, ref);

        setTimeout( function(){
          // set media back to `all` so that the stylesheet applies once it loads
          ss.media = 'all';
        },0);
      }
      loadCSS('styles.css');
    </script>
    <noscript>
      <!-- Let's not assume anything -->
      <link rel="stylesheet" href="styles.css">
    </noscript>

How to extract or unpack an .ab file (Android Backup file)

As per https://android.stackexchange.com/a/78183/239063 you can run a one line command in Linux to add in an appropriate tar header to extract it.

( printf "\x1f\x8b\x08\x00\x00\x00\x00\x00" ; tail -c +25 backup.ab ) | tar xfvz -

Replace backup.ab with the path to your file.

Is it bad practice to use break to exit a loop in Java?

No, it is not a bad practice. It is the most easiest and efficient way.

How can I enable Assembly binding logging?

Instead of Creating New Application Pool,You can go to your Existing application Pool->Right click Advance setting->Enable 32-bit Application-----Set to TRUE

Python readlines() usage and efficient practice for reading

Read line by line, not the whole file:

for line in open(file_name, 'rb'):
    # process line here

Even better use with for automatically closing the file:

with open(file_name, 'rb') as f:
    for line in f:
        # process line here

The above will read the file object using an iterator, one line at a time.

Disable firefox same origin policy

I realized my older answer is downvoted because I didn't specify how to disable FF's same origin policy specifically. Here I will give a more detailed answer:

Warning: This requires a re-compilation of FF, and the newly compiled version of Firefox will not be able to enable SOP again.

Check out Mozilla's Firefox's source code, find nsScriptSecurityManager.cpp in the src directory. I will use the one listed here as example: http://mxr.mozilla.org/aviarybranch/source/caps/src/nsScriptSecurityManager.cpp

Go to the function implementation nsScriptSecurityManager::CheckSameOriginURI, which is line 568 as of date 03/02/2016.

Make that function always return NS_OK.

This will disable SOP for good.

The browser addon answer by @Giacomo should be useful for most people and I have accepted that answer, however, for my personal research needs (TL;won't explain here) it is not enough and I figure other researchers may need to do what I did here to fully kill SOP.

Registry Key '...' has value '1.7', but '1.6' is required. Java 1.7 is Installed and the Registry is Pointing to it

For my Win7

Paradox was in being java.exe and javaw.exe in System32 folder. Opening that folder I couldn't see them but using search in Start menu I get links to those files, removed them. Next searsh gave me links to files from JAVA_HOME

magic )

Are there any style options for the HTML5 Date picker?

Currently, there is no cross browser, script-free way of styling a native date picker.

As for what's going on inside WHATWG/W3C... If this functionality does emerge, it will likely be under the CSS-UI standard or some Shadow DOM-related standard. The CSS4-UI wiki page lists a few appearance-related things that were dropped from CSS3-UI, but to be honest, there doesn't seem to be a great deal of interest in the CSS-UI module.

I think your best bet for cross browser development right now, is to implement pretty controls with JavaScript based interface, and then disable the HTML5 native UI and replace it. I think in the future, maybe there will be better native control styling, but perhaps more likely will be the ability to swap out a native control for your own Shadow DOM "widget".

It is annoying that this isn't available, and petitioning for standard support is always worthwhile. Though it does seem like jQuery UI's lead has tried and was unsuccessful.

While this is all very discouraging, it's also worth considering the advantages of the HTML5 date picker, and also why custom styles are difficult and perhaps should be avoided. On some platforms, the datepicker looks extremely different and I personally can't think of any generic way of styling the native datepicker.

In Angular, how to redirect with $location.path as $http.post success callback

Here is the changeLocation example from this article http://www.yearofmoo.com/2012/10/more-angularjs-magic-to-supercharge-your-webapp.html#apply-digest-and-phase

//be sure to inject $scope and $location
var changeLocation = function(url, forceReload) {
  $scope = $scope || angular.element(document).scope();
  if(forceReload || $scope.$$phase) {
    window.location = url;
  }
  else {
    //only use this if you want to replace the history stack
    //$location.path(url).replace();

    //this this if you want to change the URL and add it to the history stack
    $location.path(url);
    $scope.$apply();
  }
};

Eclipse Workspaces: What for and why?

I'll provide you with my vision of somebody who feels very uncomfortable in the Java world, which I assume is also your case.

What it is

A workspace is a concept of grouping together:

  1. a set of (somehow) related projects
  2. some configuration pertaining to all these projects
  3. some settings for Eclipse itself

This happens by creating a directory and putting inside it (you don't have to do it, it's done for you) files that manage to tell Eclipse these information. All you have to do explicitly is to select the folder where these files will be placed. And this folder doesn't need to be the same where you put your source code - preferentially it won't be.

Exploring each item above:

  1. a set of (somehow) related projects

Eclipse seems to always be opened in association with a particular workspace, i.e., if you are in a workspace A and decide to switch to workspace B (File > Switch Workspaces), Eclipse will close itself and reopen. All projects that were associated with workspace A (and were appearing in the Project Explorer) won't appear anymore and projects associated with workspace B will now appear. So it seems that a project, to be open in Eclipse, MUST be associated to a workspace.

Notice that this doesn't mean that the project source code must be inside the workspace. The workspace will, somehow, have a relation to the physical path of your projects in your disk (anybody knows how? I've looked inside the workspace searching for some file pointing to the projects paths, without success).

This way, a project can be inside more than 1 workspace at a time. So it seems good to keep your workspace and your source code separated.

  1. some configuration pertaining to all these projects

I heard that something, like the Java compiler version (like 1.7, e.g - I don't know if 'version' is the word here), is a workspace-level configuration. If you have several projects inside your workspace, and compile them inside of Eclipse, all of them will be compiled with the same Java compiler.

  1. some settings for Eclipse itself

Some things like your key bindings are stored at a workspace-level, also. So, if you define that ctrl+tab will switch tabs in a smart way (not stacking them), this will only be bound to your current workspace. If you want to use the same key binding in another workspace (and I think you want!), it seems that you have to export/import them between workspaces (if that's true, this IDE was built over some really strange premises). Here is a link on this.

It also seems that workspaces are not necessarily compatible between different Eclipse versions. This article suggests that you name your workspaces containing the name of the Eclipse version.

And, more important, once you pick a folder to be your workspace, don't touch any file inside there or you are in for some trouble.

How I think is a good way to use it

(actually, as I'm writing this, I don't know how to use this in a good way, that's why I was looking for an answer – that I'm trying to assemble here)

  1. Create a folder for your projects:
    /projects

  2. Create a folder for each project and group the projects' sub-projects inside of it:
    /projects/proj1/subproj1_1
    /projects/proj1/subproj1_2
    /projects/proj2/subproj2_1

  3. Create a separate folder for your workspaces:
    /eclipse-workspaces

  4. Create workspaces for your projects:
    /eclipse-workspaces/proj1
    /eclipse-workspaces/proj2

Entity Framework Migrations renaming tables and columns

In EF Core, I use the following statements to rename tables and columns:

As for renaming tables:

    protected override void Up(MigrationBuilder migrationBuilder)
    {
        migrationBuilder.RenameTable(name: "OldTableName", schema: "dbo", newName: "NewTableName", newSchema: "dbo");
    }

    protected override void Down(MigrationBuilder migrationBuilder)
    {
        migrationBuilder.RenameTable(name: "NewTableName", schema: "dbo", newName: "OldTableName", newSchema: "dbo");
    }

As for renaming columns:

    protected override void Up(MigrationBuilder migrationBuilder)
    {
        migrationBuilder.RenameColumn(name: "OldColumnName", table: "TableName", newName: "NewColumnName", schema: "dbo");
    }

    protected override void Down(MigrationBuilder migrationBuilder)
    {
        migrationBuilder.RenameColumn(name: "NewColumnName", table: "TableName", newName: "OldColumnName", schema: "dbo");
    }

What is Cache-Control: private?

To answer your question about why caching is working, even though the web-server didn't include the headers:

  • Expires: [a date]
  • Cache-Control: max-age=[seconds]

The server kindly asked any intermediate proxies to not cache the contents (i.e. the item should only be cached in a private cache, i.e. only on your own local machine):

  • Cache-Control: private

But the server forgot to include any sort of caching hints:

  • they forgot to include Expires, so the browser knows to use the cached copy until that date
  • they forgot to include Max-Age, so the browser knows how long the cached item is good for
  • they forgot to include E-Tag, so the browser can do a conditional request

But they did include a Last-Modified date in the response:

Last-Modified: Tue, 16 Oct 2012 03:13:38 GMT

Because the browser knows the date the file was modified, it can perform a conditional request. It will ask the server for the file, but instruct the server to only send the file if it has been modified since 2012/10/16 3:13:38:

GET / HTTP/1.1
If-Modified-Since: Tue, 16 Oct 2012 03:13:38 GMT

The server receives the request, realizes that the client has the most recent version already. Rather than sending the client 200 OK, followed by the contents of the page, instead it tells you that your cached version is good:

304 Not Modified

Your browser did have to suffer the delay of sending a request to the server, and wait for a response, but it did save having to re-download the static content.

Why Max-Age? Why Expires?

Because Last-Modified sucks.

Not everything on the server has a date associated with it. If I'm building a page on the fly, there is no date associated with it - it's now. But I'm perfectly willing to let the user cache the homepage for 15 seconds:

200 OK
Cache-Control: max-age=15

If the user hammers F5, they'll keep getting the cached version for 15 seconds. If it's a corporate proxy, then all 67198 users hitting the same page in the same 15-second window will all get the same contents - all served from close cache. Performance win for everyone.

The virtue of adding Cache-Control: max-age is that the browser doesn't even have to perform a conditional request.

  • if you specified only Last-Modified, the browser has to perform a request If-Modified-Since, and watch for a 304 Not Modified response
  • if you specified max-age, the browser won't even have to suffer the network round-trip; the content will come right out of the caches

The difference between "Cache-Control: max-age" and "Expires"

Expires is a legacy equivalent of the modern (c. 1998) Cache-Control: max-age header:

  • Expires: you specify a date (yuck)
  • max-age: you specify seconds (goodness)
  • And if both are specified, then the browser uses max-age:

    200 OK
    Cache-Control: max-age=60
    Expires: 20180403T192837 
    

Any web-site written after 1998 should not use Expires anymore, and instead use max-age.

What is ETag?

ETag is similar to Last-Modified, except that it doesn't have to be a date - it just has to be a something.

If I'm pulling a list of products out of a database, the server can send the last rowversion as an ETag, rather than a date:

200 OK
ETag: "247986"

My ETag can be the SHA1 hash of a static resource (e.g. image, js, css, font), or of the cached rendered page (i.e. this is what the Mozilla MDN wiki does; they hash the final markup):

200 OK
ETag: "33a64df551425fcc55e4d42a148795d9f25f89d4"

And exactly like in the case of a conditional request based on Last-Modified:

GET / HTTP/1.1
If-Modified-Since: Tue, 16 Oct 2012 03:13:38 GMT

304 Not Modified

I can perform a conditional request based on the ETag:

GET / HTTP/1.1
If-None-Match: "33a64df551425fcc55e4d42a148795d9f25f89d4"

304 Not Modified

An ETag is superior to Last-Modified because it works for things besides files, or things that have a notion of date. It just is

Creating a search form in PHP to search a database?

try this out let me know what happens.

Form:

<form action="form.php" method="post"> 
Search: <input type="text" name="term" /><br /> 
<input type="submit" value="Submit" /> 
</form> 

Form.php:

$term = mysql_real_escape_string($_REQUEST['term']);    

$sql = "SELECT * FROM liam WHERE Description LIKE '%".$term."%'";
$r_query = mysql_query($sql);

while ($row = mysql_fetch_array($r_query)){ 
echo 'Primary key: ' .$row['PRIMARYKEY']; 
echo '<br /> Code: ' .$row['Code']; 
echo '<br /> Description: '.$row['Description']; 
echo '<br /> Category: '.$row['Category']; 
echo '<br /> Cut Size: '.$row['CutSize'];  
} 

Edit: Cleaned it up a little more.

Final Cut (my test file):

<?php
$db_hostname = 'localhost';
$db_username = 'demo';
$db_password = 'demo';
$db_database = 'demo';

// Database Connection String
$con = mysql_connect($db_hostname,$db_username,$db_password);
if (!$con)
  {
  die('Could not connect: ' . mysql_error());
  }

mysql_select_db($db_database, $con);
?>

<!DOCTYPE html>
<html lang="en">
    <head>
        <meta charset="utf-8" />
        <title></title>
    </head>
    <body>
<form action="" method="post">  
Search: <input type="text" name="term" /><br />  
<input type="submit" value="Submit" />  
</form>  
<?php
if (!empty($_REQUEST['term'])) {

$term = mysql_real_escape_string($_REQUEST['term']);     

$sql = "SELECT * FROM liam WHERE Description LIKE '%".$term."%'"; 
$r_query = mysql_query($sql); 

while ($row = mysql_fetch_array($r_query)){  
echo 'Primary key: ' .$row['PRIMARYKEY'];  
echo '<br /> Code: ' .$row['Code'];  
echo '<br /> Description: '.$row['Description'];  
echo '<br /> Category: '.$row['Category'];  
echo '<br /> Cut Size: '.$row['CutSize'];   
}  

}
?>
    </body>
</html>

How to JUnit test that two List<E> contain the same elements in the same order?

assertTrue()/assertFalse() : to use only to assert boolean result returned

assertTrue(Iterables.elementsEqual(argumentComponents, returnedComponents));

You want to use Assert.assertTrue() or Assert.assertFalse() as the method under test returns a boolean value.
As the method returns a specific thing such as a List that should contain some expected elements, asserting with assertTrue() in this way : Assert.assertTrue(myActualList.containsAll(myExpectedList) is an anti pattern.
It makes the assertion easy to write but as the test fails, it also makes it hard to debug because the test runner will only say to you something like :

expected true but actual is false

Assert.assertEquals(Object, Object) in JUnit4 or Assertions.assertIterableEquals(Iterable, Iterable) in JUnit 5 : to use only as both equals() and toString() are overrided for the classes (and deeply) of the compared objects

It matters because the equality test in the assertion relies on equals() and the test failure message relies on toString() of the compared objects.
As String overrides both equals() and toString(), it is perfectly valid to assert the List<String> with assertEquals(Object,Object). And about this matter : you have to override equals() in a class because it makes sense in terms of object equality, not only to make assertions easier in a test with JUnit.
To make assertions easier you have other ways (that you can see in the next points of the answer).

Is Guava a way to perform/build unit test assertions ?

Is Google Guava Iterables.elementsEqual() the best way, provided I have the library in my build path, to compare those two lists?

No it is not. Guava is not an library to write unit test assertions.
You don't need it to write most (all I think) of unit tests.

What's the canonical way to compare lists for unit tests?

As a good practice I favor assertion/matcher libraries.

I cannot encourage JUnit to perform specific assertions because this provides really too few and limited features : it performs only an assertion with a deep equals.
Sometimes you want to allow any order in the elements, sometimes you want to allow that any elements of the expected match with the actual, and so for...

So using a unit test assertion/matcher library such as Hamcrest or AssertJ is the correct way.
The actual answer provides a Hamcrest solution. Here is a AssertJ solution.

org.assertj.core.api.ListAssert.containsExactly() is what you need : it verifies that the actual group contains exactly the given values and nothing else, in order as stated :

Verifies that the actual group contains exactly the given values and nothing else, in order.

Your test could look like :

import org.assertj.core.api.Assertions;
import org.junit.jupiter.api.Test;

@Test
void ofComponent_AssertJ() throws Exception {
   MyObject myObject = MyObject.ofComponents("One", "Two", "Three");
   Assertions.assertThat(myObject.getComponents())
             .containsExactly("One", "Two", "Three");
}

A AssertJ good point is that declaring a List as expected is needless : it makes the assertion straighter and the code more readable :

Assertions.assertThat(myObject.getComponents())
         .containsExactly("One", "Two", "Three");

And if the test fails :

// Fail : Three was not expected 
Assertions.assertThat(myObject.getComponents())
          .containsExactly("One", "Two");

you get a very clear message such as :

java.lang.AssertionError:

Expecting:

<["One", "Two", "Three"]>

to contain exactly (and in same order):

<["One", "Two"]>

but some elements were not expected:

<["Three"]>

Assertion/matcher libraries are a must because these will really further

Suppose that MyObject doesn't store Strings but Foos instances such as :

public class MyFooObject {

    private List<Foo> values;
    @SafeVarargs
    public static MyFooObject ofComponents(Foo... values) {
        // ...
    }

    public List<Foo> getComponents(){
        return new ArrayList<>(values);
    }
}

That is a very common need. With AssertJ the assertion is still simple to write. Better you can assert that the list content are equal even if the class of the elements doesn't override equals()/hashCode() while JUnit ways require that :

import org.assertj.core.api.Assertions;
import static org.assertj.core.groups.Tuple.tuple;
import org.junit.jupiter.api.Test;

@Test
void ofComponent() throws Exception {
    MyFooObject myObject = MyFooObject.ofComponents(new Foo(1, "One"), new Foo(2, "Two"), new Foo(3, "Three"));

    Assertions.assertThat(myObject.getComponents())
              .extracting(Foo::getId, Foo::getName)
              .containsExactly(tuple(1, "One"),
                               tuple(2, "Two"),
                               tuple(3, "Three"));
}

PostgreSQL error 'Could not connect to server: No such file or directory'

"Postgres.app" is a better fix if you are on OS X


Here is the fix:

  1. Stop the database
  2. cd /var
  3. sudo rm -r pgsql_socket
  4. sudo ln -s /tmp pgsql_socket
  5. chown _postgres:_postgres pgsql_socket
  6. Restart PostgreSQL (not your computer)

More information is available at "postgresql 9.0.3. on Lion Dev Preview 1".

Find Active Tab using jQuery and Twitter Bootstrap

First of all you need to remove the data-toggle attribute. We will use some JQuery, so make sure you include it.

  <ul class='nav nav-tabs'>
    <li class='active'><a href='#home'>Home</a></li>
    <li><a href='#menu1'>Menu 1</a></li>
    <li><a href='#menu2'>Menu 2</a></li>
    <li><a href='#menu3'>Menu 3</a></li>
  </ul>

  <div class='tab-content'>
    <div id='home' class='tab-pane fade in active'>
      <h3>HOME</h3>
    <div id='menu1' class='tab-pane fade'>
      <h3>Menu 1</h3>
    </div>
    <div id='menu2' class='tab-pane fade'>
      <h3>Menu 2</h3>
    </div>
    <div id='menu3' class='tab-pane fade'>
      <h3>Menu 3</h3>
    </div>
  </div>
</div>

<script>
$(document).ready(function(){
// Handling data-toggle manually
    $('.nav-tabs a').click(function(){
        $(this).tab('show');
    });
// The on tab shown event
    $('.nav-tabs a').on('shown.bs.tab', function (e) {
        alert('Hello from the other siiiiiide!');
        var current_tab = e.target;
        var previous_tab = e.relatedTarget;
    });
});
</script>

Python 3 turn range to a list

In fact, this is a retro-gradation of Python3 as compared to Python2. Certainly, Python2 which uses range() and xrange() is more convenient than Python3 which uses list(range()) and range() respectively. The reason is because the original designer of Python3 is not very experienced, they only considered the use of the range function by many beginners to iterate over a large number of elements where it is both memory and CPU inefficient; but they neglected the use of the range function to produce a number list. Now, it is too late for them to change back already.

If I was to be the designer of Python3, I will:

  1. use irange to return a sequence iterator
  2. use lrange to return a sequence list
  3. use range to return either a sequence iterator (if the number of elements is large, e.g., range(9999999) or a sequence list (if the number of elements is small, e.g., range(10))

That should be optimal.

Parsing JSON array with PHP foreach

You maybe wanted to do the following:

foreach($user->data as $mydata)

    {
         echo $mydata->name . "\n";
         foreach($mydata->values as $values)
         {
              echo $values->value . "\n";
         }
    }        

X-Frame-Options: ALLOW-FROM in firefox and chrome

ALLOW-FROM is not supported in Chrome or Safari. See MDN article: https://developer.mozilla.org/en-US/docs/Web/HTTP/X-Frame-Options

You are already doing the work to make a custom header and send it with the correct data, can you not just exclude the header when you detect it is from a valid partner and add DENY to every other request? I don't see the benefit of AllowFrom when you are already dynamically building the logic up?

I need to learn Web Services in Java. What are the different types in it?

If your application often uses http protocol then REST is best because of its light weight, and knowing that your application uses only http protocol choosing SOAP is not so good because it heavy,Better to make decision on web service selection based on the protocols we use in our applications.

Changing the position of Bootstrap popovers based on the popover's X position in relation to window edge?

You can also try this one if u need it in almost all places in the page.

U can configure it in a general way then just use it.

In this way u can also use HTML element and anything u want :)

_x000D_
_x000D_
$(document).ready(function()_x000D_
                  {_x000D_
  var options =_x000D_
      {_x000D_
        placement: function (context, source)_x000D_
        {_x000D_
          var position = $(source).position();_x000D_
          var content_width = 515;  //Can be found from a JS function for more dynamic output_x000D_
          var content_height = 110;  //Can be found from a JS function for more dynamic output_x000D_
_x000D_
          if (position.left > content_width)_x000D_
          {_x000D_
            return "left";_x000D_
          }_x000D_
_x000D_
          if (position.left < content_width)_x000D_
          {_x000D_
            return "right";_x000D_
          }_x000D_
_x000D_
          if (position.top < content_height)_x000D_
          {_x000D_
            return "bottom";_x000D_
          }_x000D_
_x000D_
          return "top";_x000D_
        }_x000D_
        , trigger: "hover"_x000D_
        , animation: "true"_x000D_
        , html:"true"_x000D_
      };_x000D_
  $('[data-toggle="popover"]').popover(options);_x000D_
});
_x000D_
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.0/jquery.min.js"></script>_x000D_
<link href="http://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap.min.css" rel="stylesheet"/>_x000D_
<script src="http://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/js/bootstrap.min.js"></script>_x000D_
_x000D_
_x000D_
<div class="container">_x000D_
 <h3>Popover Example</h3>_x000D_
 <a id="try_ppover" href="#" data-toggle="popover" title="Popover HTML Header" data-content="<div class='jumbotron'>Some HTML content inside the popover</div>">Toggle popover</a>_x000D_
</div>
_x000D_
_x000D_
_x000D_

Addition


For setting more options, u can go here.

Even more can be found here.

Update


If u want the popup after click, u can change the JS option to trigger: "click" like this-

        return ..;
    }
    ......
    , trigger: "click"
    ......
};

U also can customize it in HTML ading data-trigger="click" like this-

<a id="try_ppover" href="#" data-toggle="popover" data-trigger="click" title="Popover Header" data-content="<div class='jumbotron'>Some content inside the popover</div>">Toggle popover</a>

I think it will be more oriented code and more re-usable and more helpful to all :).

C# : Passing a Generic Object

You're missing at least a couple of things:

  • Unless you're using reflection, the type arguments need to be known at compile-time, so you can't use

    PrintGeneric<test2.GetType()>
    

    ... although in this case you don't need to anyway

  • PrintGeneric doesn't know anything about T at the moment, so the compiler can't find a member called T

Options:

  • Put a property in the ITest interface, and change PrintGeneric to constrain T:

    public void PrintGeneric<T>(T test) where T : ITest
    {
        Console.WriteLine("Generic : " + test.PropertyFromInterface);
    }
    
  • Put a property in the ITest interface and remove the generics entirely:

    public void PrintGeneric(ITest test)
    {
        Console.WriteLine("Property : " + test.PropertyFromInterface);
    }
    
  • Use dynamic typing instead of generics if you're using C# 4

receiving error: 'Error: SSL Error: SELF_SIGNED_CERT_IN_CHAIN' while using npm

The repository no longer supports self-signed certificates. You need to upgrade npm.

// Disable the certificate temporarily in order to do the upgrade
npm config set ca ""

// Upgrade npm. -g (global) means you need root permissions; be root 
// or prepend `sudo`
sudo npm install npm -g

// Undo the previous config change
npm config delete ca

// For Ubuntu/Debian-sid/Mint, node package is renamed to nodejs which 
// npm cannot find. Fix this:
sudo ln -s /usr/bin/nodejs /usr/bin/node

You need to open a new terminal session in order to use the updated npm.

Source: This was originally an edit on jnylen's answer. Although the guidelines say "We welcome all constructive edits, but please make them substantial," the edit was rejected due to "This edit changes too much in the original post; the original meaning or intent of the post would be lost." I guess the community prefers a separate answer.

How do I tell Python to convert integers into words

Use pynum2word module that can be found at sourceforge

>>> import num2word
>>> num2word.to_card(15)
'fifteen'
>>> num2word.to_card(55)
'fifty-five'
>>> num2word.to_card(1555)
'one thousand, five hundred and fifty-five'

Why are elementwise additions much faster in separate loops than in a combined loop?

The Original Question

Why is one loop so much slower than two loops?


Conclusion:

Case 1 is a classic interpolation problem that happens to be an inefficient one. I also think that this was one of the leading reasons why many machine architectures and developers ended up building and designing multi-core systems with the ability to do multi-threaded applications as well as parallel programming.

Looking at it from this kind of an approach without involving how the hardware, OS, and compiler(s) work together to do heap allocations that involve working with RAM, cache, page files, etc.; the mathematics that is at the foundation of these algorithms shows us which of these two is the better solution.

We can use an analogy of a Boss being a Summation that will represent a For Loop that has to travel between workers A & B.

We can easily see that Case 2 is at least half as fast if not a little more than Case 1 due to the difference in the distance that is needed to travel and the time taken between the workers. This math lines up almost virtually and perfectly with both the benchmark times as well as the number of differences in assembly instructions.


I will now begin to explain how all of this works below.


Assessing The Problem

The OP's code:

const int n=100000;

for(int j=0;j<n;j++){
    a1[j] += b1[j];
    c1[j] += d1[j];
}

And

for(int j=0;j<n;j++){
    a1[j] += b1[j];
}
for(int j=0;j<n;j++){
    c1[j] += d1[j];
}

The Consideration

Considering the OP's original question about the two variants of the for loops and his amended question towards the behavior of caches along with many of the other excellent answers and useful comments; I'd like to try and do something different here by taking a different approach about this situation and problem.


The Approach

Considering the two loops and all of the discussion about cache and page filing I'd like to take another approach as to looking at this from a different perspective. One that doesn't involve the cache and page files nor the executions to allocate memory, in fact, this approach doesn't even concern the actual hardware or the software at all.


The Perspective

After looking at the code for a while it became quite apparent what the problem is and what is generating it. Let's break this down into an algorithmic problem and look at it from the perspective of using mathematical notations then apply an analogy to the math problems as well as to the algorithms.


What We Do Know

We know is that this loop will run 100,000 times. We also know that a1, b1, c1 & d1 are pointers on a 64-bit architecture. Within C++ on a 32-bit machine, all pointers are 4 bytes and on a 64-bit machine, they are 8 bytes in size since pointers are of a fixed length.

We know that we have 32 bytes in which to allocate for in both cases. The only difference is we are allocating 32 bytes or two sets of 2-8 bytes on each iteration wherein the second case we are allocating 16 bytes for each iteration for both of the independent loops.

Both loops still equal 32 bytes in total allocations. With this information let's now go ahead and show the general math, algorithms, and analogy of these concepts.

We do know the number of times that the same set or group of operations that will have to be performed in both cases. We do know the amount of memory that needs to be allocated in both cases. We can assess that the overall workload of the allocations between both cases will be approximately the same.


What We Don't Know

We do not know how long it will take for each case unless if we set a counter and run a benchmark test. However, the benchmarks were already included from the original question and from some of the answers and comments as well; and we can see a significant difference between the two and this is the whole reasoning for this proposal to this problem.


Let's Investigate

It is already apparent that many have already done this by looking at the heap allocations, benchmark tests, looking at RAM, cache, and page files. Looking at specific data points and specific iteration indices were also included and the various conversations about this specific problem have many people starting to question other related things about it. How do we begin to look at this problem by using mathematical algorithms and applying an analogy to it? We start off by making a couple of assertions! Then we build out our algorithm from there.


Our Assertions:

  • We will let our loop and its iterations be a Summation that starts at 1 and ends at 100000 instead of starting with 0 as in the loops for we don't need to worry about the 0 indexing scheme of memory addressing since we are just interested in the algorithm itself.
  • In both cases we have four functions to work with and two function calls with two operations being done on each function call. We will set these up as functions and calls to functions as the following: F1(), F2(), f(a), f(b), f(c) and f(d).

The Algorithms:

1st Case: - Only one summation but two independent function calls.

Sum n=1 : [1,100000] = F1(), F2();
                       F1() = { f(a) = f(a) + f(b); }
                       F2() = { f(c) = f(c) + f(d); }

2nd Case: - Two summations but each has its own function call.

Sum1 n=1 : [1,100000] = F1();
                        F1() = { f(a) = f(a) + f(b); }

Sum2 n=1 : [1,100000] = F1();
                        F1() = { f(c) = f(c) + f(d); }

If you noticed F2() only exists in Sum from Case1 where F1() is contained in Sum from Case1 and in both Sum1 and Sum2 from Case2. This will be evident later on when we begin to conclude that there is an optimization that is happening within the second algorithm.

The iterations through the first case Sum calls f(a) that will add to its self f(b) then it calls f(c) that will do the same but add f(d) to itself for each 100000 iterations. In the second case, we have Sum1 and Sum2 that both act the same as if they were the same function being called twice in a row.

In this case we can treat Sum1 and Sum2 as just plain old Sum where Sum in this case looks like this: Sum n=1 : [1,100000] { f(a) = f(a) + f(b); } and now this looks like an optimization where we can just consider it to be the same function.


Summary with Analogy

With what we have seen in the second case it almost appears as if there is optimization since both for loops have the same exact signature, but this isn't the real issue. The issue isn't the work that is being done by f(a), f(b), f(c), and f(d). In both cases and the comparison between the two, it is the difference in the distance that the Summation has to travel in each case that gives you the difference in execution time.

Think of the for loops as being the summations that does the iterations as being a Boss that is giving orders to two people A & B and that their jobs are to meat C & D respectively and to pick up some package from them and return it. In this analogy, the for loops or summation iterations and condition checks themselves don't actually represent the Boss. What actually represents the Boss is not from the actual mathematical algorithms directly but from the actual concept of Scope and Code Block within a routine or subroutine, method, function, translation unit, etc. The first algorithm has one scope where the second algorithm has two consecutive scopes.

Within the first case on each call slip, the Boss goes to A and gives the order and A goes off to fetch B's package then the Boss goes to C and gives the orders to do the same and receive the package from D on each iteration.

Within the second case, the Boss works directly with A to go and fetch B's package until all packages are received. Then the Boss works with C to do the same for getting all of D's packages.

Since we are working with an 8-byte pointer and dealing with heap allocation let's consider the following problem. Let's say that the Boss is 100 feet from A and that A is 500 feet from C. We don't need to worry about how far the Boss is initially from C because of the order of executions. In both cases, the Boss initially travels from A first then to B. This analogy isn't to say that this distance is exact; it is just a useful test case scenario to show the workings of the algorithms.

In many cases when doing heap allocations and working with the cache and page files, these distances between address locations may not vary that much or they can vary significantly depending on the nature of the data types and the array sizes.


The Test Cases:

First Case: On first iteration the Boss has to initially go 100 feet to give the order slip to A and A goes off and does his thing, but then the Boss has to travel 500 feet to C to give him his order slip. Then on the next iteration and every other iteration after the Boss has to go back and forth 500 feet between the two.

Second Case: The Boss has to travel 100 feet on the first iteration to A, but after that, he is already there and just waits for A to get back until all slips are filled. Then the Boss has to travel 500 feet on the first iteration to C because C is 500 feet from A. Since this Boss( Summation, For Loop ) is being called right after working with A he then just waits there as he did with A until all of C's order slips are done.


The Difference In Distances Traveled

const n = 100000
distTraveledOfFirst = (100 + 500) + ((n-1)*(500 + 500);
// Simplify
distTraveledOfFirst = 600 + (99999*100);
distTraveledOfFirst = 600 + 9999900;
distTraveledOfFirst =  10000500;
// Distance Traveled On First Algorithm = 10,000,500ft

distTraveledOfSecond = 100 + 500 = 600;
// Distance Traveled On Second Algorithm = 600ft;

The Comparison of Arbitrary Values

We can easily see that 600 is far less than 10 million. Now, this isn't exact, because we don't know the actual difference in distance between which address of RAM or from which cache or page file each call on each iteration is going to be due to many other unseen variables. This is just an assessment of the situation to be aware of and looking at it from the worst-case scenario.

From these numbers it would almost appear as if algorithm one should be 99% slower than algorithm two; however, this is only the Boss's part or responsibility of the algorithms and it doesn't account for the actual workers A, B, C, & D and what they have to do on each and every iteration of the Loop. So the boss's job only accounts for about 15 - 40% of the total work being done. The bulk of the work that is done through the workers has a slightly bigger impact towards keeping the ratio of the speed rate differences to about 50-70%


The Observation: - The differences between the two algorithms

In this situation, it is the structure of the process of the work being done. It goes to show that Case 2 is more efficient from both the partial optimization of having a similar function declaration and definition where it is only the variables that differ by name and the distance traveled.

We also see that the total distance traveled in Case 1 is much farther than it is in Case 2 and we can consider this distance traveled our Time Factor between the two algorithms. Case 1 has considerable more work to do than Case 2 does.

This is observable from the evidence of the assembly instructions that were shown in both cases. Along with what was already stated about these cases, this doesn't account for the fact that in Case 1 the boss will have to wait for both A & C to get back before he can go back to A again for each iteration. It also doesn't account for the fact that if A or B is taking an extremely long time then both the Boss and the other worker(s) are idle waiting to be executed.

In Case 2 the only one being idle is the Boss until the worker gets back. So even this has an impact on the algorithm.



The OP's Amended Question(s)

EDIT: The question turned out to be of no relevance, as the behavior severely depends on the sizes of the arrays (n) and the CPU cache. So if there is further interest, I rephrase the question:

Could you provide some solid insight into the details that lead to the different cache behaviors as illustrated by the five regions on the following graph?

It might also be interesting to point out the differences between CPU/cache architectures, by providing a similar graph for these CPUs.


Regarding These Questions

As I have demonstrated without a doubt, there is an underlying issue even before the Hardware and Software becomes involved.

Now as for the management of memory and caching along with page files, etc. which all work together in an integrated set of systems between the following:

  • The architecture (hardware, firmware, some embedded drivers, kernels and assembly instruction sets).
  • The OS (file and memory management systems, drivers and the registry).
  • The compiler (translation units and optimizations of the source code).
  • And even the source code itself with its set(s) of distinctive algorithms.

We can already see that there is a bottleneck that is happening within the first algorithm before we even apply it to any machine with any arbitrary architecture, OS, and programmable language compared to the second algorithm. There already existed a problem before involving the intrinsics of a modern computer.


The Ending Results

However; it is not to say that these new questions are not of importance because they themselves are and they do play a role after all. They do impact the procedures and the overall performance and that is evident with the various graphs and assessments from many who have given their answer(s) and or comment(s).

If you paid attention to the analogy of the Boss and the two workers A & B who had to go and retrieve packages from C & D respectively and considering the mathematical notations of the two algorithms in question; you can see without the involvement of the computer hardware and software Case 2 is approximately 60% faster than Case 1.

When you look at the graphs and charts after these algorithms have been applied to some source code, compiled, optimized, and executed through the OS to perform their operations on a given piece of hardware, you can even see a little more degradation between the differences in these algorithms.

If the Data set is fairly small it may not seem all that bad of a difference at first. However, since Case 1 is about 60 - 70% slower than Case 2 we can look at the growth of this function in terms of the differences in time executions:

DeltaTimeDifference approximately = Loop1(time) - Loop2(time)
//where
Loop1(time) = Loop2(time) + (Loop2(time)*[0.6,0.7]) // approximately
// So when we substitute this back into the difference equation we end up with
DeltaTimeDifference approximately = (Loop2(time) + (Loop2(time)*[0.6,0.7])) - Loop2(time)
// And finally we can simplify this to
DeltaTimeDifference approximately = [0.6,0.7]*Loop2(time)

This approximation is the average difference between these two loops both algorithmically and machine operations involving software optimizations and machine instructions.

When the data set grows linearly, so does the difference in time between the two. Algorithm 1 has more fetches than algorithm 2 which is evident when the Boss has to travel back and forth the maximum distance between A & C for every iteration after the first iteration while algorithm 2 the Boss has to travel to A once and then after being done with A he has to travel a maximum distance only one time when going from A to C.

Trying to have the Boss focusing on doing two similar things at once and juggling them back and forth instead of focusing on similar consecutive tasks is going to make him quite angry by the end of the day since he had to travel and work twice as much. Therefore do not lose the scope of the situation by letting your boss getting into an interpolated bottleneck because the boss's spouse and children wouldn't appreciate it.



Amendment: Software Engineering Design Principles

-- The difference between local Stack and heap allocated computations within iterative for loops and the difference between their usages, their efficiencies, and effectiveness --

The mathematical algorithm that I proposed above mainly applies to loops that perform operations on data that is allocated on the heap.

  • Consecutive Stack Operations:
    • If the loops are performing operations on data locally within a single code block or scope that is within the stack frame it will still sort of apply, but the memory locations are much closer where they are typically sequential and the difference in distance traveled or execution time is almost negligible. Since there are no allocations being done within the heap, the memory isn't scattered, and the memory isn't being fetched through ram. The memory is typically sequential and relative to the stack frame and stack pointer.
  • When consecutive operations are being done on the stack, a modern processor will cache repetitive values and addresses keeping these values within local cache registers. The time of operations or instructions here is on the order of nano-seconds.
  • Consecutive Heap Allocated Operations:
    • When you begin to apply heap allocations and the processor has to fetch the memory addresses on consecutive calls, depending on the architecture of the CPU, the bus controller, and the RAM modules the time of operations or execution can be on the order of micro to milliseconds. In comparison to cached stack operations, these are quite slow.
    • The CPU will have to fetch the memory address from RAM and typically anything across the system bus is slow compared to the internal data paths or data buses within the CPU itself.

So when you are working with data that needs to be on the heap and you are traversing through them in loops, it is more efficient to keep each data set and its corresponding algorithms within its own single loop. You will get better optimizations compared to trying to factor out consecutive loops by putting multiple operations of different data sets that are on the heap into a single loop.

It is okay to do this with data that is on the stack since they are frequently cached, but not for data that has to have its memory address queried every iteration.

This is where software engineering and software architecture design comes into play. It is the ability to know how to organize your data, knowing when to cache your data, knowing when to allocate your data on the heap, knowing how to design and implement your algorithms, and knowing when and where to call them.

You might have the same algorithm that pertains to the same data set, but you might want one implementation design for its stack variant and another for its heap-allocated variant just because of the above issue that is seen from its O(n) complexity of the algorithm when working with the heap.

From what I've noticed over the years, many people do not take this fact into consideration. They will tend to design one algorithm that works on a particular data set and they will use it regardless of the data set being locally cached on the stack or if it was allocated on the heap.

If you want true optimization, yes it might seem like code duplication, but to generalize it would be more efficient to have two variants of the same algorithm. One for stack operations, and the other for heap operations that are performed in iterative loops!

Here's a pseudo example: Two simple structs, one algorithm.

struct A {
    int data;
    A() : data{0}{}
    A(int a) : data{a}{}
};
struct B {
    int data;
    B() : data{0}{}
    A(int b) : data{b}{}
}

template<typename T>
void Foo( T& t ) {
    // Do something with t
}

// Some looping operation: first stack then heap.

// Stack data:
A dataSetA[10] = {};
B dataSetB[10] = {};

// For stack operations this is okay and efficient
for (int i = 0; i < 10; i++ ) {
   Foo(dataSetA[i]);
   Foo(dataSetB[i]);
}

// If the above two were on the heap then performing
// the same algorithm to both within the same loop
// will create that bottleneck
A* dataSetA = new [] A();
B* dataSetB = new [] B();
for ( int i = 0; i < 10; i++ ) {
    Foo(dataSetA[i]); // dataSetA is on the heap here
    Foo(dataSetB[i]); // dataSetB is on the heap here
} // this will be inefficient.

// To improve the efficiency above, put them into separate loops...

for (int i = 0; i < 10; i++ ) {
    Foo(dataSetA[i]);
}
for (int i = 0; i < 10; i++ ) {
    Foo(dataSetB[i]);
}
// This will be much more efficient than above.
// The code isn't perfect syntax, it's only psuedo code
// to illustrate a point.

This is what I was referring to by having separate implementations for stack variants versus heap variants. The algorithms themselves don't matter too much, it's the looping structures that you will use them in that do.

iOS Launching Settings -> Restrictions URL Scheme

Works Fine for App Notification settings on IOS 10 (tested)

if(&UIApplicationOpenSettingsURLString != nil){
    [[UIApplication sharedApplication] openURL:[NSURL URLWithString:UIApplicationOpenSettingsURLString]];
}

When to use cla(), clf() or close() for clearing a plot in matplotlib?

They all do different things, since matplotlib uses a hierarchical order in which a figure window contains a figure which may consist of many axes. Additionally, there are functions from the pyplot interface and there are methods on the Figure class. I will discuss both cases below.

pyplot interface

pyplot is a module that collects a couple of functions that allow matplotlib to be used in a functional manner. I here assume that pyplot has been imported as import matplotlib.pyplot as plt. In this case, there are three different commands that remove stuff:

plt.cla() clears an axes, i.e. the currently active axes in the current figure. It leaves the other axes untouched.

plt.clf() clears the entire current figure with all its axes, but leaves the window opened, such that it may be reused for other plots.

plt.close() closes a window, which will be the current window, if not specified otherwise.

Which functions suits you best depends thus on your use-case.

The close() function furthermore allows one to specify which window should be closed. The argument can either be a number or name given to a window when it was created using figure(number_or_name) or it can be a figure instance fig obtained, i.e., usingfig = figure(). If no argument is given to close(), the currently active window will be closed. Furthermore, there is the syntax close('all'), which closes all figures.

methods of the Figure class

Additionally, the Figure class provides methods for clearing figures. I'll assume in the following that fig is an instance of a Figure:

fig.clf() clears the entire figure. This call is equivalent to plt.clf() only if fig is the current figure.

fig.clear() is a synonym for fig.clf()

Note that even del fig will not close the associated figure window. As far as I know the only way to close a figure window is using plt.close(fig) as described above.

JavaScript Array Push key value

You may use:


To create array of objects:

var source = ['left', 'top'];
const result = source.map(arrValue => ({[arrValue]: 0}));

Demo:

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_x000D_
var source = ['left', 'top'];_x000D_
_x000D_
const result = source.map(value => ({[value]: 0}));_x000D_
_x000D_
console.log(result);
_x000D_
_x000D_
_x000D_


Or if you wants to create a single object from values of arrays:

var source = ['left', 'top'];
const result = source.reduce((obj, arrValue) => (obj[arrValue] = 0, obj), {});

Demo:

_x000D_
_x000D_
var source = ['left', 'top'];_x000D_
_x000D_
const result = source.reduce((obj, arrValue) => (obj[arrValue] = 0, obj), {});_x000D_
_x000D_
console.log(result);
_x000D_
_x000D_
_x000D_

Redis: Show database size/size for keys

Perhaps you can do some introspection on the db file. The protocol is relatively simple (yet not well documented), so you could write a parser for it to determine which individual keys are taking up a lot of space.


New suggestions:

Have you tried using MONITOR to see what is being written, live? Perhaps you can find the issue with the data in motion.

Why can't I find SQL Server Management Studio after installation?

It appears that SQL Server 2008 R2 can be downloaded with or without the management tools. I honestly have NO IDEA why someone would not want the management tools. But either way, the options are here:

http://www.microsoft.com/sqlserver/en/us/editions/express.aspx

and the one for 64 bit WITH the management tools (management studio) is here:

http://www.microsoft.com/sqlserver/en/us/editions/express.aspx

From the first link I presented, the 3rd and 4th include the management studio for 32 and 64 bit respectively.

JSON Post with Customized HTTPHeader Field

if one wants to use .post() then this will set headers for all future request made with jquery

$.ajaxSetup({
    headers: {
        'Content-Type': 'application/json',
        'Accept': 'application/json'
    }
});

then make your .post() calls as normal.

Reading content from URL with Node.js

A slightly modified version of @sidanmor 's code. The main point is, not every webpage is purely ASCII, user should be able to handle the decoding manually (even encode into base64)

function httpGet(url) {
  return new Promise((resolve, reject) => {
    const http = require('http'),
      https = require('https');

    let client = http;

    if (url.toString().indexOf("https") === 0) {
      client = https;
    }

    client.get(url, (resp) => {
      let chunks = [];

      // A chunk of data has been recieved.
      resp.on('data', (chunk) => {
        chunks.push(chunk);
      });

      // The whole response has been received. Print out the result.
      resp.on('end', () => {
        resolve(Buffer.concat(chunks));
      });

    }).on("error", (err) => {
      reject(err);
    });
  });
}

(async(url) => {
  var buf = await httpGet(url);
  console.log(buf.toString('utf-8'));
})('https://httpbin.org/headers');

MySQL trigger if condition exists

Try to do...

 DELIMITER $$
        CREATE TRIGGER aumentarsalario 
        BEFORE INSERT 
        ON empregados
        FOR EACH ROW
        BEGIN
          if (NEW.SALARIO < 900) THEN 
             set NEW.SALARIO = NEW.SALARIO + (NEW.SALARIO * 0.1);
          END IF;
        END $$
  DELIMITER ;

Conveniently map between enum and int / String

enum ? int

yourEnum.ordinal()

int ? enum

EnumType.values()[someInt]

String ? enum

EnumType.valueOf(yourString)

enum ? String

yourEnum.name()

A side-note:
As you correctly point out, the ordinal() may be "unstable" from version to version. This is the exact reason why I always store constants as strings in my databases. (Actually, when using MySql, I store them as MySql enums!)

Pass a PHP array to a JavaScript function

In the following example you have an PHP array, then firstly create a JavaScript array by a PHP array:

<script type="javascript">
    day = new Array(<?php echo implode(',', $day); ?>);
    week = new Array(<?php echo implode(',',$week); ?>);
    month = new Array(<?php echo implode(',',$month); ?>);

    <!--  Then pass it to the JavaScript function:   -->

    drawChart(<?php echo count($day); ?>, day, week, month);
</script>

Float to String format specifier

In C#, float is an alias for System.Single (a bit like intis an alias for System.Int32).

HTTP 400 (bad request) for logical error, not malformed request syntax

HTTPbis will address the phrasing of 400 Bad Request so that it covers logical errors as well. So 400 will incorporate 422.

From https://tools.ietf.org/html/draft-ietf-httpbis-p2-semantics-18#section-7.4.1
"The server cannot or will not process the request, due to a client error (e.g., malformed syntax)"

How do the major C# DI/IoC frameworks compare?

While a comprehensive answer to this question takes up hundreds of pages of my book, here's a quick comparison chart that I'm still working on:

A table explaining difference between several DICs

Spring @ContextConfiguration how to put the right location for the xml

Our Tests look like this (using Maven and Spring 3.1):

@ContextConfiguration
(
  {
   "classpath:beans.xml",
   "file:src/main/webapp/WEB-INF/spring/applicationContext.xml",
   "file:src/main/webapp/WEB-INF/spring/dispatcher-data-servlet.xml",
   "file:src/main/webapp/WEB-INF/spring/dispatcher-servlet.xml"
  }
)
@RunWith(SpringJUnit4ClassRunner.class)
public class CCustomerCtrlTest
{
  @Resource private ApplicationContext m_oApplicationContext;
  @Autowired private RequestMappingHandlerAdapter m_oHandlerAdapter;
  @Autowired private RequestMappingHandlerMapping m_oHandlerMapping;
  private MockHttpServletRequest m_oRequest;
  private MockHttpServletResponse m_oResp;
  private CCustomerCtrl m_oCtrl;

// more code ....
}

How to sort in mongoose?

Post.find().sort({updatedAt: 1});

Fixed Table Cell Width

I had one long table td cell, this forced the table to the edges of the browser and looked ugly. I just wanted that column to be fixed size only and break the words when it reaches the specified width. So this worked well for me:

<td><div style='width: 150px;'>Text to break here</div></td>

You don't need to specify any kind of style to table, tr elements. You may also use overflow:hidden; as suggested by other answers but it causes for the excess text to disappear.

Fast and Lean PDF Viewer for iPhone / iPad / iOS - tips and hints?

I have build such kind of application using approximatively the same approach except :

  • I cache the generated image on the disk and always generate two to three images in advance in a separate thread.
  • I don't overlay with a UIImage but instead draw the image in the layer when zooming is 1. Those tiles will be released automatically when memory warnings are issued.

Whenever the user start zooming, I acquire the CGPDFPage and render it using the appropriate CTM. The code in - (void)drawLayer: (CALayer*)layer inContext: (CGContextRef) context is like :

CGAffineTransform currentCTM = CGContextGetCTM(context);    
if (currentCTM.a == 1.0 && baseImage) {
    //Calculate ideal scale
    CGFloat scaleForWidth = baseImage.size.width/self.bounds.size.width;
    CGFloat scaleForHeight = baseImage.size.height/self.bounds.size.height; 
    CGFloat imageScaleFactor = MAX(scaleForWidth, scaleForHeight);

    CGSize imageSize = CGSizeMake(baseImage.size.width/imageScaleFactor, baseImage.size.height/imageScaleFactor);
    CGRect imageRect = CGRectMake((self.bounds.size.width-imageSize.width)/2, (self.bounds.size.height-imageSize.height)/2, imageSize.width, imageSize.height);
    CGContextDrawImage(context, imageRect, [baseImage CGImage]);
} else {
    @synchronized(issue) { 
        CGPDFPageRef pdfPage = CGPDFDocumentGetPage(issue.pdfDoc, pageIndex+1);
        pdfToPageTransform = CGPDFPageGetDrawingTransform(pdfPage, kCGPDFMediaBox, layer.bounds, 0, true);
        CGContextConcatCTM(context, pdfToPageTransform);    
        CGContextDrawPDFPage(context, pdfPage);
    }
}

issue is the object containg the CGPDFDocumentRef. I synchronize the part where I access the pdfDoc property because I release it and recreate it when receiving memoryWarnings. It seems that the CGPDFDocumentRef object do some internal caching that I did not find how to get rid of.

jQuery: Setting select list 'selected' based on text, failing strangely

We can do it by searching the text in options of dropdown list and then by setting selected attribute to true.

This code is run in every environment.

 $("#numbers option:contains(" + inputText + ")").attr('selected', 'selected');

#pragma pack effect

A compiler may place structure members on particular byte boundaries for reasons of performance on a particular architecture. This may leave unused padding between members. Structure packing forces members to be contiguous.

This may be important for example if you require a structure to conform to a particular file or communications format where the data you need the data to be at specific positions within a sequence. However such usage does not deal with endian-ness issues, so although used, it may not be portable.

It may also to exactly overlay the internal register structure of some I/O device such as a UART or USB controller for example, in order that register access be through a structure rather than direct addresses.

Types in MySQL: BigInt(20) vs Int(20)

Let's give an example for int(10) one with zerofill keyword, one not, the table likes that:

create table tb_test_int_type(
    int_10 int(10),
    int_10_with_zf int(10) zerofill,
    unit int unsigned
);

Let's insert some data:

insert into tb_test_int_type(int_10, int_10_with_zf, unit)
values (123456, 123456,3147483647), (123456, 4294967291,3147483647) 
;

Then

select * from tb_test_int_type; 

# int_10, int_10_with_zf, unit
'123456', '0000123456', '3147483647'
'123456', '4294967291', '3147483647'

We can see that

  • with keyword zerofill, num less than 10 will fill 0, but without zerofill it won't

  • Secondly with keyword zerofill, int_10_with_zf becomes unsigned int type, if you insert a minus you will get error Out of range value for column...... But you can insert minus to int_10. Also if you insert 4294967291 to int_10 you will get error Out of range value for column.....

Conclusion:

  1. int(X) without keyword zerofill, is equal to int range -2147483648~2147483647

  2. int(X) with keyword zerofill, the field is equal to unsigned int range 0~4294967295, if num's length is less than X it will fill 0 to the left

Click outside menu to close in jquery

I find it more useful to use mousedown-event instead of click-event. The click-event doesn't work if the user clicks on other elements on the page with click-events. In combination with jQuery's one() method it looks like this:

$("ul.opMenu li").click(function(event){

   //event.stopPropagation(); not required any more
   $('#MainOptSubMenu').show();

   // add one mousedown event to html
   $('html').one('mousedown', function(){
       $('#MainOptSubMenu').hide();
   });
});

// mousedown must not be triggered inside menu
$("ul.opMenu li").bind('mousedown', function(evt){
    evt.stopPropagation();
});

PowerShell Script to Find and Replace for all Files with a Specific Extension

I would go with xml and xpath:

dir C:\Projects\project_*\project*.config -recurse | foreach-object{  
   $wc = [xml](Get-Content $_.fullname)
   $wc.SelectNodes("//add[@key='Environment'][@value='Dev']") | Foreach-Object {$_.value = 'Demo'}  
   $wc.Save($_.fullname)  
}

jquery $(window).width() and $(window).height() return different values when viewport has not been resized

I think what you're seeing is the hiding and showing of scrollbars. Here's a quick demo showing the width change.

As an aside: do you need to poll constantly? You might be able to optimize your code to run on the resize event, like this:

$(window).resize(function() {
  //update stuff
});

How to properly override clone method?

Use serialization to make deep copies. This is not the quickest solution but it does not depend on the type.

How to Find the Default Charset/Encoding in Java?

The behaviour is not really that strange. Looking into the implementation of the classes, it is caused by:

  • Charset.defaultCharset() is not caching the determined character set in Java 5.
  • Setting the system property "file.encoding" and invoking Charset.defaultCharset() again causes a second evaluation of the system property, no character set with the name "Latin-1" is found, so Charset.defaultCharset() defaults to "UTF-8".
  • The OutputStreamWriter is however caching the default character set and is probably used already during VM initialization, so that its default character set diverts from Charset.defaultCharset() if the system property "file.encoding" has been changed at runtime.

As already pointed out, it is not documented how the VM must behave in such a situation. The Charset.defaultCharset() API documentation is not very precise on how the default character set is determined, only mentioning that it is usually done on VM startup, based on factors like the OS default character set or default locale.

Retrieving JSON Object Literal from HttpServletRequest

The easiest way is to populate your bean would be from a Reader object, this can be done in a single call:

BufferedReader reader = request.getReader();
Gson gson = new Gson();

MyBean myBean = gson.fromJson(reader, MyBean.class);

Function pointer as a member of a C struct

You can use also "void*" (void pointer) to send an address to the function.

typedef struct pstring_t {
    char * chars;
    int(*length)(void*);
} PString;

int length(void* self) {
    return strlen(((PString*)self)->chars);
}

PString initializeString() {
    PString str;
    str.length = &length;
    return str;
}

int main()
{
    PString p = initializeString();

    p.chars = "Hello";

    printf("Length: %i\n", p.length(&p));

    return 0;
}

Output:

Length: 5

How do I set Tomcat Manager Application User Name and Password for NetBeans?

File \conf\tomcat-users.xml, before this line

</tomcat-users>

add these lines

<role rolename="manager-gui"/>
<role rolename="manager-script"/>
<role rolename="manager-jmx"/>
<role rolename="manager-status"/>   
<user username="admin" password="admin" roles="manager-gui,manager-script,manager-jmx,manager-status"/>

System.Security.SecurityException when writing to Event Log

I'm not working on IIS, but I do have an application that throws the same error on a 2K8 box. It works just fine on a 2K3 box, go figure.

My resolution was to "Run as administrator" to give the application elevated rights and everything works happily. I hope this helps lead you in the right direction.

Windows 2008 is rights/permissions/elevation is really different from Windows 2003, gar.

jQuery to retrieve and set selected option value of html select element

Try this

$('#your_select_element_id').val('your_value').attr().add('selected');

Are SSL certificates bound to the servers ip address?

The SSL certificates are going to be bound to hostname rather than IP if they are setup in the standard way. Hence why it works at one site rather than the other.

Even if the servers share the same hostname they may well have two different certificates and hence WebSphere will have a certificate trust issue as it won't be able to recognise the certificate on the second server as it is different to the first.

What is the difference between Cloud Computing and Grid Computing?

Cloud Computing is a large group of interconnected computers.The data are hidden form the user. Grid computing is more than one computers interconnected to resolve the problem.grid computing is worked in cloud computing.

Use of "this" keyword in formal parameters for static methods in C#

In addition to Preet Sangha's explanation:
Intellisense displays the extension methods with a blue arrow (e.g. in front of "Aggregate<>"):

enter image description here

You need a

using the.namespace.of.the.static.class.with.the.extension.methods;

for the extension methods to appear and to be available, if they are in a different namespace than the code using them.

PHPDoc type hinting for array of objects?

<?php foreach($this->models as /** @var Model_Object_WheelModel */ $model): ?>
    <?php
    // Type hinting now works:
    $model->getImage();
    ?>
<?php endforeach; ?>

iPhone Navigation Bar Title text color

In IOS 7 and 8, you can change the Title's color to let's say green

self.navigationController.navigationBar.titleTextAttributes = [NSDictionary dictionaryWithObject:[UIColor greenColor] forKey:NSForegroundColorAttributeName];

Watching variables in SSIS during debug

I know this is very old and possibly talking about an older version of Visual studio and so this might not have been an option before but anyway, my way would be when at a breakpoint use the locals window to see all current variable values ( Debug >> Windows >> Locals )

How to write the Fibonacci Sequence?

use recursion:

def fib(n):
    if n == 0:
        return 0
    elif n == 1:
        return 1
    else:
        return fib(n-1) + fib(n-2)
x=input('which fibonnaci do you want?')
print fib(x)

HttpContext.Current.Session is null when routing requests

a better solution is

runAllManagedModulesForAllRequest is a clever thing to do respect removing and resinserting session module.

alk.

Which is faster: Stack allocation or Heap allocation

Usually stack allocation just consists of subtracting from the stack pointer register. This is tons faster than searching a heap.

Sometimes stack allocation requires adding a page(s) of virtual memory. Adding a new page of zeroed memory doesn't require reading a page from disk, so usually this is still going to be tons faster than searching a heap (especially if part of the heap was paged out too). In a rare situation, and you could construct such an example, enough space just happens to be available in part of the heap which is already in RAM, but allocating a new page for the stack has to wait for some other page to get written out to disk. In that rare situation, the heap is faster.

Unit Testing C Code

I use CxxTest for an embedded c/c++ environment (primarily C++).

I prefer CxxTest because it has a perl/python script to build the test runner. After a small slope to get it setup (smaller still since you don't have to write the test runner), it's pretty easy to use (includes samples and useful documentation). The most work was setting up the 'hardware' the code accesses so I could unit/module test effectively. After that it's easy to add new unit test cases.

As mentioned previously it is a C/C++ unit test framework. So you will need a C++ compiler.

CxxTest User Guide CxxTest Wiki

How to terminate a process in vbscript

The Win32_Process class provides access to both 32-bit and 64-bit processes when the script is run from a 64-bit command shell.

If this is not an option for you, you can try using the taskkill command:

Dim oShell : Set oShell = CreateObject("WScript.Shell")

' Launch notepad '
oShell.Run "notepad"
WScript.Sleep 3000

' Kill notepad '
oShell.Run "taskkill /im notepad.exe", , True

Xcode warning: "Multiple build commands for output file"

This happends because ur "no.png" "d.png" and "n.png" are duplicated in resources . Just look for delete dublicated files and delete.

jQuery events .load(), .ready(), .unload()

NOTE: .load() & .unload() have been deprecated


$(window).load();

Will execute after the page along with all its contents are done loading. This means that all images, CSS (and content defined by CSS like custom fonts and images), scripts, etc. are all loaded. This happens event fires when your browser's "Stop" -icon becomes gray, so to speak. This is very useful to detect when the document along with all its contents are loaded.

$(document).ready();

This on the other hand will fire as soon as the web browser is capable of running your JavaScript, which happens after the parser is done with the DOM. This is useful if you want to execute JavaScript as soon as possible.

$(window).unload();

This event will be fired when you are navigating off the page. That could be Refresh/F5, pressing the previous page button, navigating to another website or closing the entire tab/window.

To sum up, ready() will be fired before load(), and unload() will be the last to be fired.

Why does 'git commit' not save my changes?

if you have more files in my case i have 7000 image files when i try to add them from project's route folder it hasn't added them but when i go to the image folder everything is ok. Go through the target folder and command like abows

git add .
git commit -am "image uploading"
git push origin master

git push origin master Enumerating objects: 6574, done. Counting objects: 100% (6574/6574), done. Delta compression using up to 4 threads Compressing objects: 100% (6347/6347), done. Writing objects: 28% (1850/6569), 142.17 MiB | 414.00 KiB/s

Count indexes using "for" in Python

use enumerate:

>>> l = ['a', 'b', 'c', 'd']
>>> for index, val in enumerate(l):
...    print "%d: %s" % (index, val)
... 
0: a
1: b
2: c
3: d

SQL Server String Concatenation with Null

In Sql Server:

insert into Table_Name(PersonName,PersonEmail) values(NULL,'[email protected]')

PersonName is varchar(50), NULL is not a string, because we are not passing with in single codes, so it treat as NULL.

Code Behind:

string name = (txtName.Text=="")? NULL : "'"+ txtName.Text +"'";
string email = txtEmail.Text;

insert into Table_Name(PersonName,PersonEmail) values(name,'"+email+"')

Redirect to a page/URL after alert button is pressed

Working example in php.
First Alert then Redirect works....
Enjoy...

echo "<script>";
echo " alert('Import has successfully Done.');      
        window.location.href='".site_url('home')."';
      </script>";

How to manually send HTTP POST requests from Firefox or Chrome browser?

May not be directly related to browsers but fiddler is another good software.

Fiddler web debugger

Back to previous page with header( "Location: " ); in PHP

Its so simple just use this

header("location:javascript://history.go(-1)");

Its working fine for me

Background service with location listener in android

First you need to create a Service. In that Service, create a class extending LocationListener. For this, use the following code snippet of Service:

public class LocationService extends Service {
public static final String BROADCAST_ACTION = "Hello World";
private static final int TWO_MINUTES = 1000 * 60 * 2;
public LocationManager locationManager;
public MyLocationListener listener;
public Location previousBestLocation = null;

Intent intent;
int counter = 0;

@Override
public void onCreate() {
    super.onCreate();
    intent = new Intent(BROADCAST_ACTION);
}

@Override
public void onStart(Intent intent, int startId) {
    locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
    listener = new MyLocationListener();
    if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
        return;
    }
    locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 4000, 0, (LocationListener) listener);
    locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 4000, 0, listener);
}

@Override
public IBinder onBind(Intent intent)
{
    return null;
}

protected boolean isBetterLocation(Location location, Location currentBestLocation) {
    if (currentBestLocation == null) {
        // A new location is always better than no location
        return true;
    }

    // Check whether the new location fix is newer or older
    long timeDelta = location.getTime() - currentBestLocation.getTime();
    boolean isSignificantlyNewer = timeDelta > TWO_MINUTES;
    boolean isSignificantlyOlder = timeDelta < -TWO_MINUTES;
    boolean isNewer = timeDelta > 0;

    // If it's been more than two minutes since the current location, use the new location
    // because the user has likely moved
    if (isSignificantlyNewer) {
        return true;
        // If the new location is more than two minutes older, it must be worse
    } else if (isSignificantlyOlder) {
        return false;
    }

    // Check whether the new location fix is more or less accurate
    int accuracyDelta = (int) (location.getAccuracy() - currentBestLocation.getAccuracy());
    boolean isLessAccurate = accuracyDelta > 0;
    boolean isMoreAccurate = accuracyDelta < 0;
    boolean isSignificantlyLessAccurate = accuracyDelta > 200;

    // Check if the old and new location are from the same provider
    boolean isFromSameProvider = isSameProvider(location.getProvider(),
            currentBestLocation.getProvider());

    // Determine location quality using a combination of timeliness and accuracy
    if (isMoreAccurate) {
        return true;
    } else if (isNewer && !isLessAccurate) {
        return true;
    } else if (isNewer && !isSignificantlyLessAccurate && isFromSameProvider) {
        return true;
    }
    return false;
}



/** Checks whether two providers are the same */
private boolean isSameProvider(String provider1, String provider2) {
    if (provider1 == null) {
        return provider2 == null;
    }
    return provider1.equals(provider2);
}



@Override
public void onDestroy() {
    // handler.removeCallbacks(sendUpdatesToUI);     
    super.onDestroy();
    Log.v("STOP_SERVICE", "DONE");
    locationManager.removeUpdates(listener);
}

public static Thread performOnBackgroundThread(final Runnable runnable) {
    final Thread t = new Thread() {
        @Override
        public void run() {
            try {
                runnable.run();
            } finally {

            }
        }
    };
    t.start();
    return t;
}
public class MyLocationListener implements LocationListener
{

    public void onLocationChanged(final Location loc)
    {
        Log.i("*****", "Location changed");
        if(isBetterLocation(loc, previousBestLocation)) {
            loc.getLatitude();
            loc.getLongitude();
            intent.putExtra("Latitude", loc.getLatitude());
            intent.putExtra("Longitude", loc.getLongitude());
            intent.putExtra("Provider", loc.getProvider());
            sendBroadcast(intent);

        }
    }

    @Override
    public void onStatusChanged(String provider, int status, Bundle extras) {

    }

    public void onProviderDisabled(String provider)
    {
        Toast.makeText( getApplicationContext(), "Gps Disabled", Toast.LENGTH_SHORT ).show();
    }


    public void onProviderEnabled(String provider)
    {
        Toast.makeText( getApplicationContext(), "Gps Enabled", Toast.LENGTH_SHORT).show();
    }
}

Add this Service any where in your project, the way you want! :)

Bootstrap $('#myModal').modal('show') is not working

Use .modal({show:true}) and .modal({show:false}) instead of ('show') and ('hide') ... it seems to be bootstrap / jquery version combination dependent. Hope it helps.

How to open a new file in vim in a new window

I use this subtle alias:

alias vim='gnome-terminal -- vim'

-x is deprecated now. We need to use -- instead

Image, saved to sdcard, doesn't appear in Android's Gallery app

Gallery refresh including Android KITKAT

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT)
{
        Intent mediaScanIntent = new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE);
        File f = new File("file://"+ Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES));
        Uri contentUri = Uri.fromFile(f);
        mediaScanIntent.setData(contentUri);
        this.sendBroadcast(mediaScanIntent);
}
else
{
        sendBroadcast(new Intent(Intent.ACTION_MEDIA_MOUNTED, Uri.parse("file://" + Environment.getExternalStorageDirectory())));
}

How to get a user's time zone?

NSTimeZone *timeZone = [NSTimeZone localTimeZone];
NSString *tzName = [timeZone name];

The name will be something like "Australia/Sydney", or "Europe/Lisbon".

Since it sounds like you might only care about the continent, that might be all you need.

FIFO based Queue implementations?

Queue is an interface that extends Collection in Java. It has all the functions needed to support FIFO architecture.

For concrete implementation you may use LinkedList. LinkedList implements Deque which in turn implements Queue. All of these are a part of java.util package.

For details about method with sample example you can refer FIFO based Queue implementation in Java.

PS: Above link goes to my personal blog that has additional details on this.

Is there a method for String conversion to Title Case?

Use this method to convert a string to title case :

static String toTitleCase(String word) {
    return Stream.of(word.split(" "))
            .map(w -> w.toUpperCase().charAt(0)+ w.toLowerCase().substring(1))
            .reduce((s, s2) -> s + " " + s2).orElse("");
}

How to load all modules in a folder?

I've created a module for that, which doesn't rely on __init__.py (or any other auxiliary file) and makes me type only the following two lines:

import importdir
importdir.do("Foo", globals())

Feel free to re-use or contribute: http://gitlab.com/aurelien-lourot/importdir

jQuery using append with effects

Another way when working with incoming data (like from an ajax call):

var new_div = $(data).hide();
$('#old_div').append(new_div);
new_div.slideDown();

using nth-child in tables tr td

Current css version still doesn't support selector find by content. But there is a way, by using css selector find by attribute, but you have to put some identifier on all of the <td> that have $ inside. Example: using nth-child in tables tr td

html

<tr>
    <td>&nbsp;</td>
    <td data-rel='$'>$</td>
    <td>&nbsp;</td>
</tr>

css

table tr td[data-rel='$'] {
    background-color: #333;
    color: white;
}

Please try these example.

_x000D_
_x000D_
table tr td[data-content='$'] {_x000D_
    background-color: #333;_x000D_
    color: white;_x000D_
}
_x000D_
<table border="1">_x000D_
    <tr>_x000D_
        <td>A</td>_x000D_
        <td data-content='$'>$</td>_x000D_
        <td>B</td>_x000D_
        <td data-content='$'>$</td>_x000D_
        <td>C</td>_x000D_
        <td data-content='$'>$</td>_x000D_
        <td>D</td>_x000D_
    </tr>_x000D_
</table>
_x000D_
_x000D_
_x000D_

Best way to get hostname with php

I am running PHP version 5.4 on shared hosting and both of these both successfully return the same results:

php_uname('n');

gethostname();

Using @property versus getters and setters

The short answer is: properties wins hands down. Always.

There is sometimes a need for getters and setters, but even then, I would "hide" them to the outside world. There are plenty of ways to do this in Python (getattr, setattr, __getattribute__, etc..., but a very concise and clean one is:

def set_email(self, value):
    if '@' not in value:
        raise Exception("This doesn't look like an email address.")
    self._email = value

def get_email(self):
    return self._email

email = property(get_email, set_email)

Here's a brief article that introduces the topic of getters and setters in Python.

jQuery event for images loaded

Use of the jQuery $().load() as an IMG event handler isn't guaranteed. If the image loads from the cache, some browsers may not fire off the event. In the case of (older?) versions of Safari, if you changed the SRC property of an IMG element to the same value, the onload event will NOT fire.

It appears that this is recognized in the latest jQuery (1.4.x) - http://api.jquery.com/load-event - to quote:

It is possible that the load event will not be triggered if the image is loaded from the browser cache. To account for this possibility, we can use a special load event that fires immediately if the image is ready. event.special.load is currently available as a plugin.

There is a plug-in now to recognize this case and IE's "complete" property for IMG element load states: http://github.com/peol/jquery.imgloaded/raw/master/ahpi.imgload.js

How to install SQL Server Management Studio 2012 (SSMS) Express?

Good evening,

The previous clues to get SQLManagementStudio_x64_ENU.exe runing didn't work as stated for me. After a while of searching, trying, retrying again and again, I finally figured it out. When executing SQLManagementStudio_x64_ENU.exe on my Windows seven system, I kept runing into compatibility issues. The trick is to run SQLManagementStudio_x64_ENU.exe in compatibility mode with Windows XP SP2. Edit the installer properties and enable compatibility mode with XP (service pack 2), then you'll be able to access Mr Doug (answered Mar 4 at 15:09) resolution.

Cheers.

How to change app default theme to a different app theme?

Actually you should define your styles in res/values/styles.xml. I guess now you've got the following configuration:

<style name="AppBaseTheme" parent="android:Theme.Holo.Light"/>
<style name="AppTheme" parent="AppBaseTheme"/>

so if you want to use Theme.Black then change AppBaseTheme parent to android:Theme.Black or you could change app style directly in manifest file like this - android:theme="@android:style/Theme.Black". You must be lacking android namespace before style tag.

You can read more about styles and themes here.

Is there a way to get colored text in GitHubflavored Markdown?

You cannot include style directives in GFM.

The most complete documentation/example is "Markdown Cheatsheet", and it illustrates that this element <style> is missing.

If you manage to include your text in one of the GFM elements, then you can play with a github.css stylesheet in order to colors that way, meaning to color using inline CSS style directives, referring to said css stylesheet.

Difference between "include" and "require" in php

You find the differences explained in the detailed PHP manual on the page of require:

require is identical to include except upon failure it will also produce a fatal E_COMPILE_ERROR level error. In other words, it will halt the script whereas include only emits a warning (E_WARNING) which allows the script to continue.

See @efritz's answer for an example

How to get margin value of a div in plain JavaScript?

The properties on the style object are only the styles applied directly to the element (e.g., via a style attribute or in code). So .style.marginTop will only have something in it if you have something specifically assigned to that element (not assigned via a style sheet, etc.).

To get the current calculated style of the object, you use either the currentStyle property (Microsoft) or the getComputedStyle function (pretty much everyone else).

Example:

var p = document.getElementById("target");
var style = p.currentStyle || window.getComputedStyle(p);

display("Current marginTop: " + style.marginTop);

Fair warning: What you get back may not be in pixels. For instance, if I run the above on a p element in IE9, I get back "1em".

Live Copy | Source

How do I tell whether my IE is 64-bit? (For that matter, Java too?)

Rob Heiser suggested checking out your java version by using 'java -version'.

That will identify the Java version that will be commonly found and used. Doing dev work, you can often have more than one version installed (I currently have 2 JREs - 6 and 7 - and may soon have 8).

http://www.coderanch.com/t/453224/java/java/java-version-work-setting-path

java -version will look for java.exe in the System32 directory in Windows. That's where a JRE will install it.

I'm assuming that IE either simply looks for java and that automatically starts checking in System32 or it'll use the path and hit whichever java.exe comes first in your path (if you tamper with the path to point to another JRE).

Also from what SLaks said, I would disagree with one thing. There is likely slightly better performance out of 64-it IE in 64-bit environments. So there is some reason for using it.

The type or namespace name 'System' could not be found

For me it only happened in one project and I tried everything I found online and nothing seemed to help. I was ready to delete and recreate the project when after messing through the projects properties changing the .NET framework target from 4.7.2 to 4.8 fixed the issue. I changed it back to 4.7.2 later and the error is gone.

Hopefully this helps other users as well.

How to Allow Remote Access to PostgreSQL database

If using PostgreSql 9.5.1, please follow the below configuration:

  1. Open hg_hba.conf in pgAdmin pgAdmin
  2. Select your path, and open it, then add a setting pg_hba.conf
  3. Restart postgresql service

Checking if a number is an Integer in Java

change x to 1 and output is integer, else its not an integer add to count example whole numbers, decimal numbers etc.

   double x = 1.1;
   int count = 0;
   if (x == (int)x)
    {
       System.out.println("X is an integer: " + x);
       count++; 
       System.out.println("This has been added to the count " + count);
    }else
   {
       System.out.println("X is not an integer: " + x);
       System.out.println("This has not been added to the count " + count);


   }

How to call a method daily, at specific time, in C#?

24 hours times

var DailyTime = "16:59:00";
            var timeParts = DailyTime.Split(new char[1] { ':' });

            var dateNow = DateTime.Now;
            var date = new DateTime(dateNow.Year, dateNow.Month, dateNow.Day,
                       int.Parse(timeParts[0]), int.Parse(timeParts[1]), int.Parse(timeParts[2]));
            TimeSpan ts;
            if (date > dateNow)
                ts = date - dateNow;
            else
            {
                date = date.AddDays(1);
                ts = date - dateNow;
            }

            //waits certan time and run the code
            Task.Delay(ts).ContinueWith((x) => OnTimer());

public void OnTimer()
    {
        ViewBag.ErrorMessage = "EROOROOROROOROR";
    }

Using Javascript can you get the value from a session attribute set by servlet in the HTML page

Below code may help you to achieve session attribution inside java script:

var name = '<%= session.getAttribute("username") %>';

View more than one project/solution in Visual Studio

You can create a new blank solution and add your different projects to it.

How to compare two strings are equal in value, what is the best method?

You should use some form of the String#equals(Object) method. However, there is some subtlety in how you should do it:

If you have a string literal then you should use it like this:

"Hello".equals(someString);

This is because the string literal "Hello" can never be null, so you will never run into a NullPointerException.

If you have a string and another object then you should use:

myString.equals(myObject);

You can make sure you are actually getting string equality by doing this. For all you know, myObject could be of a class that always returns true in its equals method!

Start with the object less likely to be null because this:

String foo = null;
String bar = "hello";
foo.equals(bar);

will throw a NullPointerException, but this:

String foo = null;
String bar = "hello";
bar.equals(foo);

will not. String#equals(Object) will correctly handle the case when its parameter is null, so you only need to worry about the object you are dereferencing--the first object.

Why is it faster to check if dictionary contains the key, rather than catch the exception in case it doesn't?

On the one hand, throwing exceptions is inherently expensive, because the stack has to be unwound etc.
On the other hand, accessing a value in a dictionary by its key is cheap, because it's a fast, O(1) operation.

BTW: The correct way to do this is to use TryGetValue

obj item;
if(!dict.TryGetValue(name, out item))
    return null;
return item;

This accesses the dictionary only once instead of twice.
If you really want to just return null if the key doesn't exist, the above code can be simplified further:

obj item;
dict.TryGetValue(name, out item);
return item;

This works, because TryGetValue sets item to null if no key with name exists.

How to get evaluated attributes inside a custom directive

The other answers here are very much correct, and valuable. But sometimes you just want simple: to get a plain old parsed value at directive instantiation, without needing updates, and without messing with isolate scope. For instance, it can be handy to provide a declarative payload into your directive as an array or hash-object in the form:

my-directive-name="['string1', 'string2']"

In that case, you can cut to the chase and just use a nice basic angular.$eval(attr.attrName).

element.val("value = "+angular.$eval(attr.value));

Working Fiddle.

Java int to String - Integer.toString(i) vs new Integer(i).toString()

Another option is the static String.valueOf method.

String.valueOf(i)

It feels slightly more right than Integer.toString(i) to me. When the type of i changes, for example from int to double, the code will stay correct.

Changing the git user inside Visual Studio Code

There is a conflict between Visual Studio 2015 and Visual Studio Code for the git credentials. When i changed my credentials on VS 2015 VS Code let me push with the correct git ID.

Git update submodules recursively

In recent Git (I'm using v2.15.1), the following will merge upstream submodule changes into the submodules recursively:

git submodule update --recursive --remote --merge

You may add --init to initialize any uninitialized submodules and use --rebase if you want to rebase instead of merge.

You need to commit the changes afterwards:

git add . && git commit -m 'Update submodules to latest revisions'

How do I "un-revert" a reverted Git commit?

If you haven't pushed that change yet, git reset --hard HEAD^

Otherwise, reverting the revert is perfectly fine.

Another way is to git checkout HEAD^^ -- . and then git add -A && git commit.

Rounding to 2 decimal places in SQL

Try to avoid formatting in your query. You should return your data in a raw format and let the receiving application (e.g. a reporting service or end user app) do the formatting, i.e. rounding and so on.

Formatting the data in the server makes it harder (or even impossible) for you to further process your data. You usually want export the table or do some aggregation as well, like sum, average etc. As the numbers arrive as strings (varchar), there is usually no easy way to further process them. Some report designers will even refuse to offer the option to aggregate these 'numbers'.

Also, the end user will see the country specific formatting of the server instead of his own PC.

Also, consider rounding problems. If you round the values in the server and then still do some calculations (supposing the client is able to revert the number-strings back to a number), you will end up getting wrong results.

AngularJS Directive Restrict A vs E

The restrict option is typically set to:

  • 'A' - only matches attribute name
  • 'E' - only matches element name
  • 'C' - only matches class name
  • 'M' - only matches comment

Here is the documentation link.

What is the reason for java.lang.IllegalArgumentException: No enum const class even though iterating through values() works just fine?

That's because you defined your own version of name for your enum, and getByName doesn't use that.

getByName("COLUMN_HEADINGS") would probably work.

Is there a way to check if a file is in use?

I once needed to upload PDFs to an online backup archive. But the backup would fail if the user had the file open in another program (such as PDF reader). In my haste, I attempted a few of the top answers in this thread but could not get them to work. What did work for me was trying to move the PDF file to its own directory. I found that this would fail if the file was open in another program, and if the move were successful there would be no restore-operation required as there would be if it were moved to a separate directory. I want to post my basic solution in case it may be useful for others' specific use cases.

string str_path_and_name = str_path + '\\' + str_filename;
FileInfo fInfo = new FileInfo(str_path_and_name);
bool open_elsewhere = false;
try
{
    fInfo.MoveTo(str_path_and_name);
}
catch (Exception ex)
{
    open_elsewhere = true;
}

if (open_elsewhere)
{
    //handle case
}

What's the difference between Instant and LocalDateTime?

Table of all date-time types in Java, both modern and legacy

tl;dr

Instant and LocalDateTime are two entirely different animals: One represents a moment, the other does not.

  • Instant represents a moment, a specific point in the timeline.
  • LocalDateTime represents a date and a time-of-day. But lacking a time zone or offset-from-UTC, this class cannot represent a moment. It represents potential moments along a range of about 26 to 27 hours, the range of all time zones around the globe. A LocalDateTime value is inherently ambiguous.

Incorrect Presumption

LocalDateTime is rather date/clock representation including time-zones for humans.

Your statement is incorrect: A LocalDateTime has no time zone. Having no time zone is the entire point of that class.

To quote that class’ doc:

This class does not store or represent a time-zone. Instead, it is a description of the date, as used for birthdays, combined with the local time as seen on a wall clock. It cannot represent an instant on the time-line without additional information such as an offset or time-zone.

So Local… means “not zoned, no offset”.

Instant

enter image description here

An Instant is a moment on the timeline in UTC, a count of nanoseconds since the epoch of the first moment of 1970 UTC (basically, see class doc for nitty-gritty details). Since most of your business logic, data storage, and data exchange should be in UTC, this is a handy class to be used often.

Instant instant = Instant.now() ;  // Capture the current moment in UTC.

OffsetDateTime

enter image description here

The class OffsetDateTime class represents a moment as a date and time with a context of some number of hours-minutes-seconds ahead of, or behind, UTC. The amount of offset, the number of hours-minutes-seconds, is represented by the ZoneOffset class.

If the number of hours-minutes-seconds is zero, an OffsetDateTime represents a moment in UTC the same as an Instant.

ZoneOffset

enter image description here

The ZoneOffset class represents an offset-from-UTC, a number of hours-minutes-seconds ahead of UTC or behind UTC.

A ZoneOffset is merely a number of hours-minutes-seconds, nothing more. A zone is much more, having a name and a history of changes to offset. So using a zone is always preferable to using a mere offset.

ZoneId

enter image description here

A time zone is represented by the ZoneId class.

A new day dawns earlier in Paris than in Montréal, for example. So we need to move the clock’s hands to better reflect noon (when the Sun is directly overhead) for a given region. The further away eastward/westward from the UTC line in west Europe/Africa the larger the offset.

A time zone is a set of rules for handling adjustments and anomalies as practiced by a local community or region. The most common anomaly is the all-too-popular lunacy known as Daylight Saving Time (DST).

A time zone has the history of past rules, present rules, and rules confirmed for the near future.

These rules change more often than you might expect. Be sure to keep your date-time library's rules, usually a copy of the 'tz' database, up to date. Keeping up-to-date is easier than ever now in Java 8 with Oracle releasing a Timezone Updater Tool.

Specify a proper time zone name in the format of Continent/Region, such as America/Montreal, Africa/Casablanca, or Pacific/Auckland. Never use the 2-4 letter abbreviation such as EST or IST as they are not true time zones, not standardized, and not even unique(!).

Time Zone = Offset + Rules of Adjustments

ZoneId z = ZoneId.of( “Africa/Tunis” ) ; 

ZonedDateTime

enter image description here

Think of ZonedDateTime conceptually as an Instant with an assigned ZoneId.

ZonedDateTime = ( Instant + ZoneId )

To capture the current moment as seen in the wall-clock time used by the people of a particular region (a time zone):

ZonedDateTime zdt = ZonedDateTime.now( z ) ;  // Pass a `ZoneId` object such as `ZoneId.of( "Europe/Paris" )`. 

Nearly all of your backend, database, business logic, data persistence, data exchange should all be in UTC. But for presentation to users you need to adjust into a time zone expected by the user. This is the purpose of the ZonedDateTime class and the formatter classes used to generate String representations of those date-time values.

ZonedDateTime zdt = instant.atZone( z ) ;
String output = zdt.toString() ;                 // Standard ISO 8601 format.

You can generate text in localized format using DateTimeFormatter.

DateTimeFormatter f = DateTimeFormatter.ofLocalizedDateTime( FormatStyle.FULL ).withLocale( Locale.CANADA_FRENCH ) ; 
String outputFormatted = zdt.format( f ) ;

mardi 30 avril 2019 à 23 h 22 min 55 s heure de l’Inde

LocalDate, LocalTime, LocalDateTime

Diagram showing only a calendar for a LocalDate.

Diagram showing only a clock for a LocalTime.

Diagram showing a calendar plus clock for a LocalDateTime.

The "local" date time classes, LocalDateTime, LocalDate, LocalTime, are a different kind of critter. The are not tied to any one locality or time zone. They are not tied to the timeline. They have no real meaning until you apply them to a locality to find a point on the timeline.

The word “Local” in these class names may be counter-intuitive to the uninitiated. The word means any locality, or every locality, but not a particular locality.

So for business apps, the "Local" types are not often used as they represent just the general idea of a possible date or time not a specific moment on the timeline. Business apps tend to care about the exact moment an invoice arrived, a product shipped for transport, an employee was hired, or the taxi left the garage. So business app developers use Instant and ZonedDateTime classes most commonly.

So when would we use LocalDateTime? In three situations:

  • We want to apply a certain date and time-of-day across multiple locations.
  • We are booking appointments.
  • We have an intended yet undetermined time zone.

Notice that none of these three cases involve a single certain specific point on the timeline, none of these are a moment.

One time-of-day, multiple moments

Sometimes we want to represent a certain time-of-day on a certain date, but want to apply that into multiple localities across time zones.

For example, "Christmas starts at midnight on the 25th of December 2015" is a LocalDateTime. Midnight strikes at different moments in Paris than in Montréal, and different again in Seattle and in Auckland.

LocalDate ld = LocalDate.of( 2018 , Month.DECEMBER , 25 ) ;
LocalTime lt = LocalTime.MIN ;   // 00:00:00
LocalDateTime ldt = LocalDateTime.of( ld , lt ) ;  // Christmas morning anywhere. 

Another example, "Acme Company has a policy that lunchtime starts at 12:30 PM at each of its factories worldwide" is a LocalTime. To have real meaning you need to apply it to the timeline to figure the moment of 12:30 at the Stuttgart factory or 12:30 at the Rabat factory or 12:30 at the Sydney factory.

Booking appointments

Another situation to use LocalDateTime is for booking future events (ex: Dentist appointments). These appointments may be far enough out in the future that you risk politicians redefining the time zone. Politicians often give little forewarning, or even no warning at all. If you mean "3 PM next January 23rd" regardless of how the politicians may play with the clock, then you cannot record a moment – that would see 3 PM turn into 2 PM or 4 PM if that region adopted or dropped Daylight Saving Time, for example.

For appointments, store a LocalDateTime and a ZoneId, kept separately. Later, when generating a schedule, on-the-fly determine a moment by calling LocalDateTime::atZone( ZoneId ) to generate a ZonedDateTime object.

ZonedDateTime zdt = ldt.atZone( z ) ;  // Given a date, a time-of-day, and a time zone, determine a moment, a point on the timeline.

If needed, you can adjust to UTC. Extract an Instant from the ZonedDateTime.

Instant instant = zdt.toInstant() ;  // Adjust from some zone to UTC. Same moment, same point on the timeline, different wall-clock time.

Unknown zone

Some people might use LocalDateTime in a situation where the time zone or offset is unknown.

I consider this case inappropriate and unwise. If a zone or offset is intended but undetermined, you have bad data. That would be like storing a price of a product without knowing the intended currency (dollars, pounds, euros, etc.). Not a good idea.

All date-time types

For completeness, here is a table of all the possible date-time types, both modern and legacy in Java, as well as those defined by the SQL standard. This might help to place the Instant & LocalDateTime classes in a larger context.

Table of all date-time types in Java (both modern & legacy) as well as SQL standard.

Notice the odd choices made by the Java team in designing JDBC 4.2. They chose to support all the java.time times… except for the two most commonly used classes: Instant & ZonedDateTime.

But not to worry. We can easily convert back and forth.

Converting Instant.

// Storing
OffsetDateTime odt = instant.atOffset( ZoneOffset.UTC ) ;
myPreparedStatement.setObject( … , odt ) ;

// Retrieving
OffsetDateTime odt = myResultSet.getObject( … , OffsetDateTime.class ) ;
Instant instant = odt.toInstant() ;

Converting ZonedDateTime.

// Storing
OffsetDateTime odt = zdt.toOffsetDateTime() ;
myPreparedStatement.setObject( … , odt ) ;

// Retrieving
OffsetDateTime odt = myResultSet.getObject( … , OffsetDateTime.class ) ;
ZoneId z = ZoneId.of( "Asia/Kolkata" ) ;
ZonedDateTime zdt = odt.atZone( z ) ; 

About java.time

The java.time framework is built into Java 8 and later. These classes supplant the troublesome old legacy date-time classes such as java.util.Date, Calendar, & SimpleDateFormat.

To learn more, see the Oracle Tutorial. And search Stack Overflow for many examples and explanations. Specification is JSR 310.

The Joda-Time project, now in maintenance mode, advises migration to the java.time classes.

You may exchange java.time objects directly with your database. Use a JDBC driver compliant with JDBC 4.2 or later. No need for strings, no need for java.sql.* classes. Hibernate 5 & JPA 2.2 support java.time.

Where to obtain the java.time classes?

Table of which java.time library to use with which version of Java or Android

The ThreeTen-Extra project extends java.time with additional classes. This project is a proving ground for possible future additions to java.time. You may find some useful classes here such as Interval, YearWeek, YearQuarter, and more.

Get selected row item in DataGrid WPF

Just discovered this one after i tried Fara's answer but it didn't work on my project. Just drag the column from the Data Sources window, and drop to the Label or TextBox.

Is it possible to set UIView border properties from interface builder?

while this might set the properties, it doesnt actually reflect in IB. So if you're essentially writing code in IB, you might as well then do it in your source code

XML element with attribute and content using JAXB

The correct scheme should be:

<?xml version="1.0" encoding="UTF-8"?>
<schema xmlns="http://www.w3.org/2001/XMLSchema" 
targetNamespace="http://www.example.org/Sport"
xmlns:tns="http://www.example.org/Sport" 
elementFormDefault="qualified"
xmlns:jaxb="http://java.sun.com/xml/ns/jaxb" 
jaxb:version="2.0">

<complexType name="sportType">
    <simpleContent>
        <extension base="string">
            <attribute name="type" type="string" />
            <attribute name="gender" type="string" />
        </extension>
    </simpleContent>
</complexType>

<element name="sports">
    <complexType>
        <sequence>
            <element name="sport" minOccurs="0" maxOccurs="unbounded"
                type="tns:sportType" />
        </sequence>
    </complexType>
</element>

Code generated for SportType will be:

package org.example.sport;

import javax.xml.bind.annotation.XmlAccessType;
import javax.xml.bind.annotation.XmlAccessorType;
import javax.xml.bind.annotation.XmlAttribute;
import javax.xml.bind.annotation.XmlType;


@XmlAccessorType(XmlAccessType.FIELD)
@XmlType(name = "sportType")
public class SportType {
    @XmlValue
    protected String value;
    @XmlAttribute
    protected String type;
    @XmlAttribute
    protected String gender;

    public String getValue() {
        return value;
    }

    public void setValue(String value) {
        this.value = value;
    }

    public String getType() {
    return type;
    }


    public void setType(String value) {
        this.type = value;
    }

    public String getGender() {
        return gender;
    }

    public void setGender(String value) {
        this.gender = value;
    }
}

How to remove extension from string (only real extension!)

Recommend use: pathinfo with PATHINFO_FILENAME

$filename = 'abc_123_filename.html';
$without_extension = pathinfo($filename, PATHINFO_FILENAME);

how to permit an array with strong parameters

It should be like

params.permit(:id => [])

Also since rails version 4+ you can use:

params.permit(id: [])

The multi-part identifier could not be bound

I was struggling with the same error message in SQL SERVER, since I had multiple joins, changing the order of the joins solved it for me.

Adding and removing style attribute from div with jquery

In case of .css method in jQuery for !important rule will not apply.

In this case we should use .attr function.

For Example: If you want to add style as below:

<div id='voltaic_holder' style='position:absolute;top:-75px !important'>

You should use:

$("#voltaic_holder").attr("style", "position:absolute;top:-75px !important");

Hope it helps some one.

Calculating Waiting Time and Turnaround Time in (non-preemptive) FCFS queue

For non-preemptive system,

waitingTime = startTime - arrivalTime

turnaroundTime = burstTime + waitingTime = finishTime- arrivalTime

startTime = Time at which the process started executing

finishTime = Time at which the process finished executing

You can keep track of the current time elapsed in the system(timeElapsed). Assign all processors to a process in the beginning, and execute until the shortest process is done executing. Then assign this processor which is free to the next process in the queue. Do this until the queue is empty and all processes are done executing. Also, whenever a process starts executing, recored its startTime, when finishes, record its finishTime (both same as timeElapsed). That way you can calculate what you need.

customize Android Facebook Login button

Customize com.facebook.widget.LoginButton

step:1 Creating a Framelayout.

step:2 To set com.facebook.widget.LoginButton

step:3 To set Textview with customizable.

<FrameLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    >
    <com.facebook.widget.LoginButton
        android:id="@+id/fbLogin"
        android:layout_width="match_parent"
        android:layout_height="50dp"
        android:contentDescription="@string/app_name"
        facebook:confirm_logout="false"
        facebook:fetch_user_info="true"
        facebook:login_text=""
        facebook:logout_text="" />

    <TextView
        android:id="@+id/tv_radio_setting_login"
        android:layout_width="match_parent"
        android:layout_height="50dp"
        android:layout_centerHorizontal="true"
        android:background="@drawable/drawable_radio_setting_loginbtn"
        android:gravity="center"
        android:padding="10dp"
        android:textColor="@android:color/white"
        android:textSize="18sp" />
</FrameLayout>

MUST REMEMBER

1> com.facebook.widget.LoginButton & TextView Height/Width Same

2> 1st declate com.facebook.widget.LoginButton then TextView

3> To perform login/logout using TextView's Click-Listener

Android set bitmap to Imageview

Please try this:

byte[] decodedString = Base64.decode(person_object.getPhoto(),Base64.NO_WRAP);
InputStream inputStream  = new ByteArrayInputStream(decodedString);
Bitmap bitmap  = BitmapFactory.decodeStream(inputStream);
user_image.setImageBitmap(bitmap);

Upload folder with subfolders using S3 and the AWS console

Solution 1:

var AWS = require('aws-sdk');
var path = require("path");
var fs = require('fs');

const uploadDir = function(s3Path, bucketName) {

    let s3 = new AWS.S3({
    accessKeyId: process.env.S3_ACCESS_KEY,
    secretAccessKey: process.env.S3_SECRET_KEY
    });

    function walkSync(currentDirPath, callback) {
        fs.readdirSync(currentDirPath).forEach(function (name) {
            var filePath = path.join(currentDirPath, name);
            var stat = fs.statSync(filePath);
            if (stat.isFile()) {
                callback(filePath, stat);
            } else if (stat.isDirectory()) {
                walkSync(filePath, callback);
            }
        });
    }

    walkSync(s3Path, function(filePath, stat) {
        let bucketPath = filePath.substring(s3Path.length+1);
        let params = {Bucket: bucketName, Key: bucketPath, Body: fs.readFileSync(filePath) };
        s3.putObject(params, function(err, data) {
            if (err) {
                console.log(err)
            } else {
                console.log('Successfully uploaded '+ bucketPath +' to ' + bucketName);
            }
        });

    });
};
uploadDir("path to your folder", "your bucket name");

Solution 2:

aws s3 cp SOURCE_DIR s3://DEST_BUCKET/ --recursive

Choose File Dialog

Was looking for a file/folder browser myself recently and decided to make a new explorer activity (Android library): https://github.com/vaal12/AndroidFileBrowser

Matching Test application https://github.com/vaal12/FileBrowserTestApplication- is a sample how to use.

Allows picking directories and files from phone file structure.

MySQL: View with Subquery in the FROM Clause Limitation

Couldn't your query just be written as:

SELECT u1.name as UserName from Message m1, User u1 
  WHERE u1.uid = m1.UserFromID GROUP BY u1.name HAVING count(m1.UserFromId)>3

That should also help with the known speed issues with subqueries in MySQL

How do I look inside a Python object?

import pprint

pprint.pprint(obj.__dict__)

or

pprint.pprint(vars(obj))

Pyspark: Exception: Java gateway process exited before sending the driver its port number

I figured out the problem in Windows system. The installation directory for Java must not have blanks in the path such as in C:\Program Files. I re-installed Java in C\Java. I set JAVA_HOME to C:\Java and the problem went away.

Get custom product attributes in Woocommerce

You can get the single value for the attribute with below code:

$pa_koostis_value = get_post_meta($product->id, 'pa_koostis', true);

SSIS cannot convert because a potential loss of data

This might not be the best method, but you can ignore the conversion error if all else fails. Mine was an issue of nulls not converting properly, so I just ignored the error and the dates came in as dates and the nulls came in as nulls, so no data quality issues--not that this would always be the case. To do this, right click on your source, click Edit, then Error Output. Go to the column that's giving you grief and under Error change it to Ignore Failure.

"Post Image data using POSTMAN"

Follow the below steps:

  1. No need to give any type of header.
  2. Select body > form-data and do same as shown in the image. 1

  3. Now in your Django view.py

def post(self, request, *args, **kwargs):
    image = request.FILES["image"]
    data = json.loads(request.data['data'])
    ...
    return Response(...)
  1. You can access all the keys (id, uid etc..) from the data variable.

Access is denied when attaching a database

Every time I have run into this issue was when attempting to attach a database that is in a different directory from the default database directory that is setup in SQL server.

I would highly recommend that instead of jacking with permissions on various directories and accounts that you simply move your data file into the directory that sql server expects to find it.

jquery live hover

$('.hoverme').live('mouseover mouseout', function(event) {
  if (event.type == 'mouseover') {
    // do something on mouseover
  } else {
    // do something on mouseout
  }
});

http://api.jquery.com/live/

Conditional Count on a field

You could join the table against itself:

select
   t.jobId, t.jobName,
   count(p1.jobId) as Priority1,
   count(p2.jobId) as Priority2,
   count(p3.jobId) as Priority3,
   count(p4.jobId) as Priority4,
   count(p5.jobId) as Priority5
from
   theTable t
   left join theTable p1 on p1.jobId = t.jobId and p1.jobName = t.jobName and p1.Priority = 1
   left join theTable p2 on p2.jobId = t.jobId and p2.jobName = t.jobName and p2.Priority = 2
   left join theTable p3 on p3.jobId = t.jobId and p3.jobName = t.jobName and p3.Priority = 3
   left join theTable p4 on p4.jobId = t.jobId and p4.jobName = t.jobName and p4.Priority = 4
   left join theTable p5 on p5.jobId = t.jobId and p5.jobName = t.jobName and p5.Priority = 5
group by
   t.jobId, t.jobName

Or you could use case inside a sum:

select
   jobId, jobName,
   sum(case Priority when 1 then 1 else 0 end) as Priority1,
   sum(case Priority when 2 then 1 else 0 end) as Priority2,
   sum(case Priority when 3 then 1 else 0 end) as Priority3,
   sum(case Priority when 4 then 1 else 0 end) as Priority4,
   sum(case Priority when 5 then 1 else 0 end) as Priority5
from
   theTable
group by
   jobId, jobName

Can I extend a class using more than 1 class in PHP?

<?php
// what if we want to extend more than one class?

abstract class ExtensionBridge
{
    // array containing all the extended classes
    private $_exts = array();
    public $_this;

    function __construct() {$_this = $this;}

    public function addExt($object)
    {
        $this->_exts[]=$object;
    }

    public function __get($varname)
    {
        foreach($this->_exts as $ext)
        {
            if(property_exists($ext,$varname))
            return $ext->$varname;
        }
    }

    public function __call($method,$args)
    {
        foreach($this->_exts as $ext)
        {
            if(method_exists($ext,$method))
            return call_user_method_array($method,$ext,$args);
        }
        throw new Exception("This Method {$method} doesn't exists");
    }


}

class Ext1
{
    private $name="";
    private $id="";
    public function setID($id){$this->id = $id;}
    public function setName($name){$this->name = $name;}
    public function getID(){return $this->id;}
    public function getName(){return $this->name;}
}

class Ext2
{
    private $address="";
    private $country="";
    public function setAddress($address){$this->address = $address;}
    public function setCountry($country){$this->country = $country;}
    public function getAddress(){return $this->address;}
    public function getCountry(){return $this->country;}
}

class Extender extends ExtensionBridge
{
    function __construct()
    {
        parent::addExt(new Ext1());
        parent::addExt(new Ext2());
    }

    public function __toString()
    {
        return $this->getName().', from: '.$this->getCountry();
    }
}

$o = new Extender();
$o->setName("Mahdi");
$o->setCountry("Al-Ahwaz");
echo $o;
?>

Efficient thresholding filter of an array with numpy

b = a[a>threshold] this should do

I tested as follows:

import numpy as np, datetime
# array of zeros and ones interleaved
lrg = np.arange(2).reshape((2,-1)).repeat(1000000,-1).flatten()

t0 = datetime.datetime.now()
flt = lrg[lrg==0]
print datetime.datetime.now() - t0

t0 = datetime.datetime.now()
flt = np.array(filter(lambda x:x==0, lrg))
print datetime.datetime.now() - t0

I got

$ python test.py
0:00:00.028000
0:00:02.461000

http://docs.scipy.org/doc/numpy/user/basics.indexing.html#boolean-or-mask-index-arrays

@viewChild not working - cannot read property nativeElement of undefined

The accepted answer is correct in all means and I stumbled upon this thread after I couldn't get the Google Map render in one of my app components.

Now, if you are on a recent angular version i.e. 7+ of angular then you will have to deal with the following ViewChild declaration i.e.

@ViewChild(selector: string | Function | Type<any>, opts: {
read?: any;
static: boolean;
})

Now, the interesting part is the static value, which by definition says

  • static - True to resolve query results before change detection runs

Now for rendering a map, I used the following ,

@ViewChild('map', { static: true }) mapElement: any;
  map: google.maps.Map;

How do I load the contents of a text file into a javascript variable?

here is how I did it in jquery:

jQuery.get('http://localhost/foo.txt', function(data) {
    alert(data);
});

How to search a string in String array

Why the prohibition "I don't want to use any looping"? That's the most obvious solution. When given the chance to be obvious, take it!

Note that calls like arr.Contains(...) are still going to loop, it just won't be you who has written the loop.

Have you considered an alternate representation that's more amenable to searching?

  • A good Set implementation would perform well. (HashSet, TreeSet or the local equivalent).
  • If you can be sure that arr is sorted, you could use binary search (which would need to recurse or loop, but not as often as a straight linear search).

Presenting a UIAlertController properly on an iPad using iOS 8

You can present a UIAlertController from a popover by using UIPopoverPresentationController.

In Obj-C:

UIViewController *self; // code assumes you're in a view controller
UIButton *button; // the button you want to show the popup sheet from

UIAlertController *alertController;
UIAlertAction *destroyAction;
UIAlertAction *otherAction;

alertController = [UIAlertController alertControllerWithTitle:nil
                                                      message:nil
                           preferredStyle:UIAlertControllerStyleActionSheet];
destroyAction = [UIAlertAction actionWithTitle:@"Remove All Data"
                                         style:UIAlertActionStyleDestructive
                                       handler:^(UIAlertAction *action) {
                                           // do destructive stuff here
                                       }];
otherAction = [UIAlertAction actionWithTitle:@"Blah"
                                       style:UIAlertActionStyleDefault
                                     handler:^(UIAlertAction *action) {
                                         // do something here
                                     }];
// note: you can control the order buttons are shown, unlike UIActionSheet
[alertController addAction:destroyAction];
[alertController addAction:otherAction];
[alertController setModalPresentationStyle:UIModalPresentationPopover];

UIPopoverPresentationController *popPresenter = [alertController 
                                              popoverPresentationController];
popPresenter.sourceView = button;
popPresenter.sourceRect = button.bounds;
[self presentViewController:alertController animated:YES completion:nil];

Editing for Swift 4.2, though there are many blogs available for the same but it may save your time to go and search for them.

if let popoverController = yourAlert.popoverPresentationController {
    popoverController.sourceView = self.view //to set the source of your alert
    popoverController.sourceRect = CGRect(x: self.view.bounds.midX, y: self.view.bounds.midY, width: 0, height: 0) // you can set this as per your requirement.
    popoverController.permittedArrowDirections = [] //to hide the arrow of any particular direction
}

Initializing a two dimensional std::vector

The general syntax, as depicted already is:

std::vector<std::vector<int> > v (A_NUMBER, std::vector <int> (OTHER_NUMBER, DEFAULT_VALUE))  

Here, the vector 'v' can be visualised as a two dimensional array, with 'A_NUMBER' of rows, with 'OTHER_NUMBER' of columns with their initial value set to 'DEFAULT_VALUE'.

Also it can be written like this:

std::vector <int> line(OTHER_NUMBER, DEFAULT_VALUE)
std::vector<std::vector<int> > v(A_NUMBER, line)

Inputting values in a 2-D vector is similar to inputting values in a 2-D array:

for(int i = 0; i < A_NUMBER; i++) {
     for(int j = 0; j < OTHER_NUMBER; j++) {
         std::cin >> v[i][j]
     }
}

Examples have already been stated in other answers....!

How do you produce a .d.ts "typings" definition file from an existing JavaScript library?

As Ryan says, the tsc compiler has a switch --declaration which generates a .d.ts file from a .ts file. Also note that (barring bugs) TypeScript is supposed to be able to compile Javascript, so you can pass existing javascript code to the tsc compiler.

SQL Case Expression Syntax?

The complete syntax depends on the database engine you're working with:

For SQL Server:

CASE case-expression
    WHEN when-expression-1 THEN value-1
  [ WHEN when-expression-n THEN value-n ... ]
  [ ELSE else-value ]
END

or:

CASE
    WHEN boolean-when-expression-1 THEN value-1
  [ WHEN boolean-when-expression-n THEN value-n ... ]
  [ ELSE else-value ]
END

expressions, etc:

case-expression    - something that produces a value
when-expression-x  - something that is compared against the case-expression
value-1            - the result of the CASE statement if:
                         the when-expression == case-expression
                      OR the boolean-when-expression == TRUE
boolean-when-exp.. - something that produces a TRUE/FALSE answer

Link: CASE (Transact-SQL)

Also note that the ordering of the WHEN statements is important. You can easily write multiple WHEN clauses that overlap, and the first one that matches is used.

Note: If no ELSE clause is specified, and no matching WHEN-condition is found, the value of the CASE expression will be NULL.

How to make a gap between two DIV within the same column

I know this was an old answer, but i would like to share my simple solution.

give style="margin-top:5px"

<div style="margin-top:5px">
  div 1
</div>
<div style="margin-top:5px">
  div2 elements
</div> 
div3 elements

How to get back to the latest commit after checking out a previous commit?

If your latest commit is on the master branch, you can simply use

git checkout master

How to make zsh run as a login shell on Mac OS X (in iTerm)?

Have you tried editing the shell entry in account settings.

Go to the Accounts preferences, unlock, and right-click on your user account for the Advanced Settings dialog. Your shell should be /bin/zsh, and you can edit that invocation appropriately (i.e. add the --login argument).

Bootstrap 3 - set height of modal window according to screen size

I assume you want to make modal use as much screen space as possible on phones. I've made a plugin to fix this UX problem of Bootstrap modals on mobile phones, you can check it out here - https://github.com/keaukraine/bootstrap-fs-modal

All you will need to do is to apply modal-fullscreen class and it will act similar to native screens of iOS/Android.

How to get difference between two rows for a column field?

SELECT
   [current].rowInt,
   [current].Value,
   ISNULL([next].Value, 0) - [current].Value
FROM
   sourceTable       AS [current]
LEFT JOIN
   sourceTable       AS [next]
      ON [next].rowInt = (SELECT MIN(rowInt) FROM sourceTable WHERE rowInt > [current].rowInt)

EDIT:

Thinking about it, using a subquery in the select (ala Quassnoi's answer) may be more efficient. I would trial different versions, and look at the execution plans to see which would perform best on the size of data set that you have...


EDIT2:

I still see this garnering votes, though it's unlikely many people still use SQL Server 2005.

If you have access to Windowed Functions such as LEAD(), then use that instead...

SELECT
  RowInt,
  Value,
  LEAD(Value, 1, 0) OVER (ORDER BY RowInt) - Value
FROM
  sourceTable

How to specify a multi-line shell variable?

read does not export the variable (which is a good thing most of the time). Here's an alternative which can be exported in one command, can preserve or discard linefeeds, and allows mixing of quoting-styles as needed. Works for bash and zsh.

oneLine=$(printf %s \
    a   \
    " b "   \
    $'\tc\t'    \
    'd '    \
)
multiLine=$(printf '%s\n' \
    a   \
    " b "   \
    $'\tc\t'    \
    'd '    \
)

I admit the need for quoting makes this ugly for SQL, but it answers the (more generally expressed) question in the title.

I use it like this

export LS_COLORS=$(printf %s    \
    ':*rc=36:*.ini=36:*.inf=36:*.cfg=36:*~=33:*.bak=33:*$=33'   \
    ...
    ':bd=40;33;1:cd=40;33;1:or=1;31:mi=31:ex=00')

in a file sourced from both my .bashrc and .zshrc.

Creating files in C++

#include <iostream>
#include <fstream>

int main() {
  std::ofstream o("Hello.txt");

  o << "Hello, World\n" << std::endl;

  return 0;
}

How to use Jquery how to change the aria-expanded="false" part of a dom element (Bootstrap)?

You can use .attr() as a part of however you plan to toggle it:

$("button").attr("aria-expanded","true");

AngularJS: ng-repeat list is not updated when a model element is spliced from the model array

Whenever you do some form of operation outside of AngularJS, such as doing an Ajax call with jQuery, or binding an event to an element like you have here you need to let AngularJS know to update itself. Here is the code change you need to do:

app.directive("remove", function () {
    return function (scope, element, attrs) {
        element.bind ("mousedown", function () {
            scope.remove(element);
            scope.$apply();
        })
    };

});

app.directive("resize", function () {
    return function (scope, element, attrs) {
        element.bind ("mousedown", function () {
            scope.resize(element);
            scope.$apply();
        })
    };
});

Here is the documentation on it: https://docs.angularjs.org/api/ng/type/$rootScope.Scope#$apply

What is a loop invariant?

The meaning of invariant is never change

Here the loop invariant means "The change which happen to variable in the loop(increment or decrement) is not changing the loop condition i.e the condition is satisfying " so that the loop invariant concept has came

Support for the experimental syntax 'classProperties' isn't currently enabled

Moving the state inside the constructor function worked for me:

...
class MyComponent extends Component {
  constructor(man) {
    super(man)
    this.state = {}
  }
}
...

Good Luck...

How do I get bit-by-bit data from an integer value in C?

Here's one way to do it—there are many others:

bool b[4];
int v = 7;  // number to dissect

for (int j = 0;  j < 4;  ++j)
   b [j] =  0 != (v & (1 << j));

It is hard to understand why use of a loop is not desired, but it is easy enough to unroll the loop:

bool b[4];
int v = 7;  // number to dissect

b [0] =  0 != (v & (1 << 0));
b [1] =  0 != (v & (1 << 1));
b [2] =  0 != (v & (1 << 2));
b [3] =  0 != (v & (1 << 3));

Or evaluating constant expressions in the last four statements:

b [0] =  0 != (v & 1);
b [1] =  0 != (v & 2);
b [2] =  0 != (v & 4);
b [3] =  0 != (v & 8);

How should I escape commas and speech marks in CSV files so they work in Excel?

We eventually found the answer to this.

Excel will only respect the escaping of commas and speech marks if the column value is NOT preceded by a space. So generating the file without spaces like this...

Reference,Title,Description
1,"My little title","My description, which may contain ""speech marks"" and commas."
2,"My other little title","My other description, which may also contain ""speech marks"" and commas."

... fixed the problem. Hope this helps someone!

WP -- Get posts by category?

Create a taxonomy field category (field name = post_category) and import it in your template as shown below:

<?php
          $categ = get_field('post_category');  
          $args = array( 'posts_per_page' => 6,
         'category_name' => $categ->slug );
          $myposts = get_posts( $args );
          foreach ( $myposts as $post ) : setup_postdata( $post ); ?>
            //your code here
          <?php endforeach; 
          wp_reset_postdata();?>

Conflict with dependency 'com.android.support:support-annotations' in project ':app'. Resolved versions for app (26.1.0) and test app (27.1.1) differ.

Based on your screenshot i found two working solutions:

First solution: add to dependencies of your gradle module this line

compile 'com.android.support:support-annotations:27.1.1'

and sync your project

Note: if you are using Android studio 3+ change compile to implementation

Second solution: Configure project-wide properties found in the documentation https://developer.android.com/studio/build/gradle-tips.html#configure-project-wide-properties

in project gradle add this line:

// This block encapsulates custom properties and makes them available to all
// modules in the project.
ext {
    // The following are only a few examples of the types of properties you can define.
    compileSdkVersion = 26
    // You can also use this to specify versions for dependencies. Having consistent
    // versions between modules can avoid behavior conflicts.
    supportLibVersion = "27.1.1"
}

Then to access this section change compileSdkVersionline to be

compileSdkVersion rootProject.ext.compileSdkVersion

and at dependencies section change the imported library to be like this:

compile "com.android.support:appcompat-v7:${rootProject.ext.supportLibVersion}"

and sync your project

Note: if you are using Android studio 3+ change compile to implementation

For the difference between compile and implementation look at this What's the difference between implementation and compile in gradle

How to escape regular expression special characters using javascript?

Use the \ character to escape a character that has special meaning inside a regular expression.

To automate it, you could use this:

function escapeRegExp(text) {
  return text.replace(/[-[\]{}()*+?.,\\^$|#\s]/g, '\\$&');
}

Update: There is now a proposal to standardize this method, possibly in ES2016: https://github.com/benjamingr/RegExp.escape

Update: The abovementioned proposal was rejected, so keep implementing this yourself if you need it.

What is a LAMP stack?

There are various technological stacks present. Have a look:

LAMP:

Linux
Apache
MySQL
PHP

WAMP:

Windows
Apache
MySQL
PHP

MAMP:

Mac operating system
Apache web server
MySQL as database
PHP for scripting

XAMPP:

X is cross-platform
Apache
MySQL
PHP
Perl

MEAN:

MongoDB
Express.js
Angular
Node.js

MERN:

MongoDB
Express.js
React
Node.js

python int( ) function

Integers (int for short) are the numbers you count with 0, 1, 2, 3 ... and their negative counterparts ... -3, -2, -1 the ones without the decimal part.

So once you introduce a decimal point, your not really dealing with integers. You're dealing with rational numbers. The Python float or decimal types are what you want to represent or approximate these numbers.

You may be used to a language that automatically does this for you(Php). Python, though, has an explicit preference for forcing code to be explicit instead implicit.

Increasing Heap Size on Linux Machines

Changing Tomcat config wont effect all JVM instances to get theses settings. This is not how it works, the setting will be used only to launch JVMs used by Tomcat, not started in the shell.

Look here for permanently changing the heap size.

Run git pull over all subdirectories

Run the following from the parent directory, plugins in this case:

find . -type d -depth 1 -exec git --git-dir={}/.git --work-tree=$PWD/{} pull origin master \;

To clarify:

  • find . searches the current directory
  • -type d to find directories, not files
  • -depth 1 for a maximum depth of one sub-directory
  • -exec {} \; runs a custom command for every find
  • git --git-dir={}/.git --work-tree=$PWD/{} pull git pulls the individual directories

To play around with find, I recommend using echo after -exec to preview, e.g.:

find . -type d -depth 1 -exec echo git --git-dir={}/.git --work-tree=$PWD/{} status \;

Note: if the -depth 1 option is not available, try -mindepth 1 -maxdepth 1.

How to make a great R reproducible example

Basically a minimal reproducible example (MWE) should enable others to exactly reproduce your issue on their machines.

A MWE consists of the following items:

  • a minimal dataset, necessary to demonstrate the problem
  • the minimal runnable code necessary to reproduce the error, which can be run on the given dataset
  • all necessary information on the used packages, the R version, and the OS it is run on.
  • in the case of random processes, a seed (set by set.seed()) for reproducibility

For examples of good MWEs, see section "Examples" at the bottom of help files on the function you are using. Simply type e.g. help(mean), or short ?mean into your R console.

Providing a minimal dataset

Usually, sharing huge data sets is not necessary and may rather discourage others from reading your question. Therefore, it is better to use built-in datasets or create a small "toy" example that resembles your original data, which is actually what is meant by minimal. If for some reason you really need to share your original data, you should use a method, such as dput(), that allows others to get an exact copy of your data.

Built-in datasets

You can use one of the built-in datasets. A comprehensive list of built-in datasets can be seen with data(). There is a short description of every data set, and more information can be obtained, e.g. with ?iris, for the 'iris' data set that comes with R. Installed packages might contain additional datasets.

Creating example data sets

Preliminary note: Sometimes you may need special formats (i.e. classes), such as factors, dates, or time series. For these, make use of functions like: as.factor, as.Date, as.xts, ... Example:

d <- as.Date("2020-12-30")

where

class(d)
# [1] "Date"

Vectors

x <- rnorm(10)  ## random vector normal distributed
x <- runif(10)  ## random vector uniformly distributed    
x <- sample(1:100, 10)  ## 10 random draws out of 1, 2, ..., 100    
x <- sample(LETTERS, 10)  ## 10 random draws out of built-in latin alphabet

Matrices

m <- matrix(1:12, 3, 4, dimnames=list(LETTERS[1:3], LETTERS[1:4]))
m
#   A B C  D
# A 1 4 7 10
# B 2 5 8 11
# C 3 6 9 12

Data frames

set.seed(42)  ## for sake of reproducibility
n <- 6
dat <- data.frame(id=1:n, 
                  date=seq.Date(as.Date("2020-12-26"), as.Date("2020-12-31"), "day"),
                  group=rep(LETTERS[1:2], n/2),
                  age=sample(18:30, n, replace=TRUE),
                  type=factor(paste("type", 1:n)),
                  x=rnorm(n))
dat
#   id       date group age   type         x
# 1  1 2020-12-26     A  27 type 1 0.0356312
# 2  2 2020-12-27     B  19 type 2 1.3149588
# 3  3 2020-12-28     A  20 type 3 0.9781675
# 4  4 2020-12-29     B  26 type 4 0.8817912
# 5  5 2020-12-30     A  26 type 5 0.4822047
# 6  6 2020-12-31     B  28 type 6 0.9657529

Note: Although it is widely used, better do not name your data frame df, because df() is an R function for the density (i.e. height of the curve at point x) of the F distribution and you might get a clash with it.

Copying original data

If you have a specific reason, or data that would be too difficult to construct an example from, you could provide a small subset of your original data, best by using dput.

Why use dput()?

dput throws all information needed to exactly reproduce your data on your console. You may simply copy the output and paste it into your question.

Calling dat (from above) produces output that still lacks information about variable classes and other features if you share it in your question. Furthermore the spaces in the type column make it difficult to do anything with it. Even when we set out to use the data, we won't manage to get important features of your data right.

  id       date group age   type         x
1  1 2020-12-26     A  27 type 1 0.0356312
2  2 2020-12-27     B  19 type 2 1.3149588
3  3 2020-12-28     A  20 type 3 0.9781675

Subset your data

Tho share a subset, use head(), subset() or the indices iris[1:4, ]. Then wrap it into dput() to give others something that can be put in R immediately. Example

dput(iris[1:4, ]) # first four rows of the iris data set

Console output to share in your question:

structure(list(Sepal.Length = c(5.1, 4.9, 4.7, 4.6), Sepal.Width = c(3.5, 
3, 3.2, 3.1), Petal.Length = c(1.4, 1.4, 1.3, 1.5), Petal.Width = c(0.2, 
0.2, 0.2, 0.2), Species = structure(c(1L, 1L, 1L, 1L), .Label = c("setosa", 
"versicolor", "virginica"), class = "factor")), row.names = c(NA, 
4L), class = "data.frame")

When using dput, you may also want to include only relevant columns, e.g. dput(mtcars[1:3, c(2, 5, 6)])

Note: If your data frame has a factor with many levels, the dput output can be unwieldy because it will still list all the possible factor levels even if they aren't present in the the subset of your data. To solve this issue, you can use the droplevels() function. Notice below how species is a factor with only one level, e.g. dput(droplevels(iris[1:4, ])). One other caveat for dput is that it will not work for keyed data.table objects or for grouped tbl_df (class grouped_df) from the tidyverse. In these cases you can convert back to a regular data frame before sharing, dput(as.data.frame(my_data)).

Producing minimal code

Combined with the minimal data (see above), your code should exactly reproduce the problem on another machine by simply copying and pasting it.

This should be the easy part but often isn't. What you should not do:

  • showing all kinds of data conversions; make sure the provided data is already in the correct format (unless that is the problem, of course)
  • copy-paste a whole script that gives an error somewhere. Try to locate which lines exactly result in the error. More often than not, you'll find out what the problem is yourself.

What you should do:

  • add which packages you use if you use any (using library())
  • test run your code in a fresh R session to ensure the code is runnable. People should be able to copy-paste your data and your code in the console and get the same as you have.
  • if you open connections or create files, add some code to close them or delete the files (using unlink())
  • if you change options, make sure the code contains a statement to revert them back to the original ones. (eg op <- par(mfrow=c(1,2)) ...some code... par(op) )

Providing necessary information

In most cases, just the R version and the operating system will suffice. When conflicts arise with packages, giving the output of sessionInfo() can really help. When talking about connections to other applications (be it through ODBC or anything else), one should also provide version numbers for those, and if possible, also the necessary information on the setup.

If you are running R in R Studio, using rstudioapi::versionInfo() can help report your RStudio version.

If you have a problem with a specific package, you may want to provide the package version by giving the output of packageVersion("name of the package").

Seed

Using set.seed() you may specify a seed1, i.e. the specific state, R's random number generator is fixed. This makes it possible for random functions, such as sample(), rnorm(), runif() and lots of others, to always return the same result, Example:

set.seed(42)
rnorm(3)
# [1]  1.3709584 -0.5646982  0.3631284

set.seed(42)
rnorm(3)
# [1]  1.3709584 -0.5646982  0.3631284

1 Note: The output of set.seed() differs between R >3.6.0 and previous versions. Specify which R version you used for the random process, and don't be surprised if you get slightly different results when following old questions. To get the same result in such cases, you can use the RNGversion()-function before set.seed() (e.g.: RNGversion("3.5.2")).

Python Function to test ping

It looks like you want the return keyword

def check_ping():
    hostname = "taylor"
    response = os.system("ping -c 1 " + hostname)
    # and then check the response...
    if response == 0:
        pingstatus = "Network Active"
    else:
        pingstatus = "Network Error"

    return pingstatus

You need to capture/'receive' the return value of the function(pingstatus) in a variable with something like:

pingstatus = check_ping()

NOTE: ping -c is for Linux, for Windows use ping -n

Some info on python functions:

http://www.tutorialspoint.com/python/python_functions.htm

http://www.learnpython.org/en/Functions

It's probably worth going through a good introductory tutorial to Python, which will cover all the fundamentals. I recommend investigating Udacity.com and codeacademy.com

Python error: "IndexError: string index out of range"

There were several problems in your code. Here you have a functional version you can analyze (Lets set 'hello' as the target word):

word = 'hello'
so_far = "-" * len(word)       # Create variable so_far to contain the current guess

while word != so_far:          # if still not complete
    print(so_far)
    guess = input('>> ')       # get a char guess

    if guess in word:
        print("\nYes!", guess, "is in the word!")

        new = ""
        for i in range(len(word)):  
            if guess == word[i]:
                new += guess        # fill the position with new value
            else:
                new += so_far[i]    # same value as before
        so_far = new
    else:
        print("try_again")

print('finish')

I tried to write it for py3k with a py2k ide, be careful with errors.

How could I create a list in c++?

Create list using C++ templates

i.e

template <class T> struct Node 
{
    T data;
    Node * next;
};
    
template <class T> class List 
{
    Node<T> *head,*tail;
        
    public: 
        void push(T const&);  // push element 
        void pop();           // pop element 
        bool empty()          // return true if empty. 
}; 

Then you can write the code like:

List<MyClass>;

The type T is not dynamic in run time.It is only for the compile time.

For complete example click here.

For C++ templates tutorial click here.

MySQL Error 1215: Cannot add foreign key constraint

This also happens when the type of the columns is not the same.

e.g. if the column you are referring to is UNSIGNED INT and the column being referred is INT then you get this error.

Notepad++ Multi editing

Notepad++ only has column editing. This is not completely the same as multiple cursors.

Sublime Text has a marvelous implementation of this, might be worth checking out...
It's a relatively new editor (2011) that is gaining popularity quite fast: http://www.google.com/trends/explore#q=Notepad%2B%2B%2C%20Sublime%20Text&cmpt=q

Edit: Apparently somewhere around Notepad++ version 6.x multi-cursor editing got added, but there are still a few more advanced features for it in Sublime, like "select next occurrence".

Why is division in Ruby returning an integer instead of decimal value?

Change the 5 to 5.0. You're getting integer division.

DateTime format to SQL format using C#

The Answer i was looking for was:

DateTime myDateTime = DateTime.Now;
string sqlFormattedDate = myDateTime.ToString("yyyy-MM-dd HH:mm:ss");

I've also learned that you can do it this way:

DateTime myDateTime = DateTime.Now;
string sqlFormattedDate = myDateTime.ToString(myCountryDateFormat);

where myCountryDateFormat can be changed to meet change depending on requirement.

Please note that the tagged "This question may already have an answer here:" has not actually answered the question because as you can see it used a ".Date" instead of omitting it. It's quite confusing for new programmers of .NET

When is TCP option SO_LINGER (0) required?

I like Maxim's observation that DOS attacks can exhaust server resources. It also happens without an actually malicious adversary.

Some servers have to deal with the 'unintentional DOS attack' which occurs when the client app has a bug with connection leak, where they keep creating a new connection for every new command they send to your server. And then perhaps eventually closing their connections if they hit GC pressure, or perhaps the connections eventually time out.

Another scenario is when 'all clients have the same TCP address' scenario. Then client connections are distinguishable only by port numbers (if they connect to a single server). And if clients start rapidly cycling opening/closing connections for any reason they can exhaust the (client addr+port, server IP+port) tuple-space.

So I think servers may be best advised to switch to the Linger-Zero strategy when they see a high number of sockets in the TIME_WAIT state - although it doesn't fix the client behavior, it might reduce the impact.

Url to a google maps page to show a pin given a latitude / longitude?

From my notes:

http://maps.google.com/maps?q=37.4185N+122.08774W+(label)&ll=37.419731,-122.088715&spn=0.004250,0.011579&t=h&iwloc=A&hl=en

Which parses like this:

    q=latN+lonW+(label)     location of teardrop

    t=k             keyhole (satelite map)
    t=h             hybrid

    ll=lat,-lon     center of map
    spn=w.w,h.h     span of map, degrees

iwloc has something to do with the info window. hl is obviously language.

See also: http://www.seomoz.org/ugc/everything-you-never-wanted-to-know-about-google-maps-parameters

What are POD types in C++?

Examples of all non-POD cases with static_assert from C++11 to C++17 and POD effects

std::is_pod was added in C++11, so let's consider that standard onwards for now.

std::is_pod will be removed from C++20 as mentioned at https://stackoverflow.com/a/48435532/895245 , let's update this as support arrives for the replacements.

POD restrictions have become more and more relaxed as the standard evolved, I aim to cover all relaxations in the example through ifdefs.

libstdc++ has at tiny bit of testing at: https://github.com/gcc-mirror/gcc/blob/gcc-8_2_0-release/libstdc%2B%2B-v3/testsuite/20_util/is_pod/value.cc but it just too little. Maintainers: please merge this if you read this post. I'm lazy to check out all the C++ testsuite projects mentioned at: https://softwareengineering.stackexchange.com/questions/199708/is-there-a-compliance-test-for-c-compilers

#include <type_traits>
#include <array>
#include <vector>

int main() {
#if __cplusplus >= 201103L
    // # Not POD
    //
    // Non-POD examples. Let's just walk all non-recursive non-POD branches of cppreference.
    {
        // Non-trivial implies non-POD.
        // https://en.cppreference.com/w/cpp/named_req/TrivialType
        {
            // Has one or more default constructors, all of which are either
            // trivial or deleted, and at least one of which is not deleted.
            {
                // Not trivial because we removed the default constructor
                // by using our own custom non-default constructor.
                {
                    struct C {
                        C(int) {}
                    };
                    static_assert(std::is_trivially_copyable<C>(), "");
                    static_assert(!std::is_trivial<C>(), "");
                    static_assert(!std::is_pod<C>(), "");
                }

                // No, this is not a default trivial constructor either:
                // https://en.cppreference.com/w/cpp/language/default_constructor
                //
                // The constructor is not user-provided (i.e., is implicitly-defined or
                // defaulted on its first declaration)
                {
                    struct C {
                        C() {}
                    };
                    static_assert(std::is_trivially_copyable<C>(), "");
                    static_assert(!std::is_trivial<C>(), "");
                    static_assert(!std::is_pod<C>(), "");
                }
            }

            // Not trivial because not trivially copyable.
            {
                struct C {
                    C(C&) {}
                };
                static_assert(!std::is_trivially_copyable<C>(), "");
                static_assert(!std::is_trivial<C>(), "");
                static_assert(!std::is_pod<C>(), "");
            }
        }

        // Non-standard layout implies non-POD.
        // https://en.cppreference.com/w/cpp/named_req/StandardLayoutType
        {
            // Non static members with different access control.
            {
                // i is public and j is private.
                {
                    struct C {
                        public:
                            int i;
                        private:
                            int j;
                    };
                    static_assert(!std::is_standard_layout<C>(), "");
                    static_assert(!std::is_pod<C>(), "");
                }

                // These have the same access control.
                {
                    struct C {
                        private:
                            int i;
                            int j;
                    };
                    static_assert(std::is_standard_layout<C>(), "");
                    static_assert(std::is_pod<C>(), "");

                    struct D {
                        public:
                            int i;
                            int j;
                    };
                    static_assert(std::is_standard_layout<D>(), "");
                    static_assert(std::is_pod<D>(), "");
                }
            }

            // Virtual function.
            {
                struct C {
                    virtual void f() = 0;
                };
                static_assert(!std::is_standard_layout<C>(), "");
                static_assert(!std::is_pod<C>(), "");
            }

            // Non-static member that is reference.
            {
                struct C {
                    int &i;
                };
                static_assert(!std::is_standard_layout<C>(), "");
                static_assert(!std::is_pod<C>(), "");
            }

            // Neither:
            //
            // - has no base classes with non-static data members, or
            // - has no non-static data members in the most derived class
            //   and at most one base class with non-static data members
            {
                // Non POD because has two base classes with non-static data members.
                {
                    struct Base1 {
                        int i;
                    };
                    struct Base2 {
                        int j;
                    };
                    struct C : Base1, Base2 {};
                    static_assert(!std::is_standard_layout<C>(), "");
                    static_assert(!std::is_pod<C>(), "");
                }

                // POD: has just one base class with non-static member.
                {
                    struct Base1 {
                        int i;
                    };
                    struct C : Base1 {};
                    static_assert(std::is_standard_layout<C>(), "");
                    static_assert(std::is_pod<C>(), "");
                }

                // Just one base class with non-static member: Base1, Base2 has none.
                {
                    struct Base1 {
                        int i;
                    };
                    struct Base2 {};
                    struct C : Base1, Base2 {};
                    static_assert(std::is_standard_layout<C>(), "");
                    static_assert(std::is_pod<C>(), "");
                }
            }

            // Base classes of the same type as the first non-static data member.
            // TODO failing on GCC 8.1 -std=c++11, 14 and 17.
            {
                struct C {};
                struct D : C {
                    C c;
                };
                //static_assert(!std::is_standard_layout<C>(), "");
                //static_assert(!std::is_pod<C>(), "");
            };

            // C++14 standard layout new rules, yay!
            {
                // Has two (possibly indirect) base class subobjects of the same type.
                // Here C has two base classes which are indirectly "Base".
                //
                // TODO failing on GCC 8.1 -std=c++11, 14 and 17.
                // even though the example was copy pasted from cppreference.
                {
                    struct Q {};
                    struct S : Q { };
                    struct T : Q { };
                    struct U : S, T { };  // not a standard-layout class: two base class subobjects of type Q
                    //static_assert(!std::is_standard_layout<U>(), "");
                    //static_assert(!std::is_pod<U>(), "");
                }

                // Has all non-static data members and bit-fields declared in the same class
                // (either all in the derived or all in some base).
                {
                    struct Base { int i; };
                    struct Middle : Base {};
                    struct C : Middle { int j; };
                    static_assert(!std::is_standard_layout<C>(), "");
                    static_assert(!std::is_pod<C>(), "");
                }

                // None of the base class subobjects has the same type as
                // for non-union types, as the first non-static data member
                //
                // TODO: similar to the C++11 for which we could not make a proper example,
                // but with recursivity added.

                // TODO come up with an example that is POD in C++14 but not in C++11.
            }
        }
    }

    // # POD
    //
    // POD examples. Everything that does not fall neatly in the non-POD examples.
    {
        // Can't get more POD than this.
        {
            struct C {};
            static_assert(std::is_pod<C>(), "");
            static_assert(std::is_pod<int>(), "");
        }

        // Array of POD is POD.
        {
            struct C {};
            static_assert(std::is_pod<C>(), "");
            static_assert(std::is_pod<C[]>(), "");
        }

        // Private member: became POD in C++11
        // https://stackoverflow.com/questions/4762788/can-a-class-with-all-private-members-be-a-pod-class/4762944#4762944
        {
            struct C {
                private:
                    int i;
            };
#if __cplusplus >= 201103L
            static_assert(std::is_pod<C>(), "");
#else
            static_assert(!std::is_pod<C>(), "");
#endif
        }

        // Most standard library containers are not POD because they are not trivial,
        // which can be seen directly from their interface definition in the standard.
        // https://stackoverflow.com/questions/27165436/pod-implications-for-a-struct-which-holds-an-standard-library-container
        {
            static_assert(!std::is_pod<std::vector<int>>(), "");
            static_assert(!std::is_trivially_copyable<std::vector<int>>(), "");
            // Some might be though:
            // https://stackoverflow.com/questions/3674247/is-stdarrayt-s-guaranteed-to-be-pod-if-t-is-pod
            static_assert(std::is_pod<std::array<int, 1>>(), "");
        }
    }

    // # POD effects
    //
    // Now let's verify what effects does PODness have.
    //
    // Note that this is not easy to do automatically, since many of the
    // failures are undefined behaviour.
    //
    // A good initial list can be found at:
    // https://stackoverflow.com/questions/4178175/what-are-aggregates-and-pods-and-how-why-are-they-special/4178176#4178176
    {
        struct Pod {
            uint32_t i;
            uint64_t j;
        };
        static_assert(std::is_pod<Pod>(), "");

        struct NotPod {
            NotPod(uint32_t i, uint64_t j) : i(i), j(j) {}
            uint32_t i;
            uint64_t j;
        };
        static_assert(!std::is_pod<NotPod>(), "");

        // __attribute__((packed)) only works for POD, and is ignored for non-POD, and emits a warning
        // https://stackoverflow.com/questions/35152877/ignoring-packed-attribute-because-of-unpacked-non-pod-field/52986680#52986680
        {
            struct C {
                int i;
            };

            struct D : C {
                int j;
            };

            struct E {
                D d;
            } /*__attribute__((packed))*/;

            static_assert(std::is_pod<C>(), "");
            static_assert(!std::is_pod<D>(), "");
            static_assert(!std::is_pod<E>(), "");
        }
    }
#endif
}

GitHub upstream.

Tested with:

for std in 11 14 17; do echo $std; g++-8 -Wall -Werror -Wextra -pedantic -std=c++$std pod.cpp; done

on Ubuntu 18.04, GCC 8.2.0.

How to convert a PIL Image into a numpy array?

def imshow(img):
    img = img / 2 + 0.5     # unnormalize
    npimg = img.numpy()
    plt.imshow(np.transpose(npimg, (1, 2, 0)))
    plt.show()

You can transform the image into numpy by parsing the image into numpy() function after squishing out the features( unnormalization)

SQL Server stored procedure parameters

I'm going on a bit of an assumption here, but I'm assuming the logic inside the procedure gets split up via task. And you cant have nullable parameters as @Yuck suggested because of the dynamics of the parameters?

So going by my assumption

If TaskName = "Path1" Then Something

If TaskName = "Path2" Then Something Else

My initial thought is, if you have separate functions with business-logic you need to create, and you can determine that you have say 5-10 different scenarios, rather write individual stored procedures as needed, instead of trying one huge one solution fits all approach. Might get a bit messy to maintain.

But if you must...

Why not try dynamic SQL, as suggested by @E.J Brennan (Forgive me, i haven't touched SQL in a while so my syntax might be rusty) That being said i don't know if its the best approach, but could this could possibly meet your needs?

CREATE PROCEDURE GetTaskEvents
    @TaskName varchar(50)
    @Values varchar(200)
AS
BEGIN
  DECLARE @SQL VARCHAR(MAX)

  IF @TaskName = 'Something'
  BEGIN
    @SQL = 'INSERT INTO.....' + CHAR(13)
    @SQL += @Values + CHAR(13) 
  END

  IF @TaskName = 'Something Else'
  BEGIN
    @SQL = 'DELETE SOMETHING WHERE' + CHAR(13)
    @SQL += @Values + CHAR(13) 
  END

  PRINT(@SQL)
  EXEC(@SQL)    
END

(The CHAR(13) adds a new line.. an old habbit i picked up somewhere, used to help debugging/reading dynamic procedures when running SQL profiler.)

Using SimpleXML to create an XML object from scratch

Sure you can. Eg.

<?php
$newsXML = new SimpleXMLElement("<news></news>");
$newsXML->addAttribute('newsPagePrefix', 'value goes here');
$newsIntro = $newsXML->addChild('content');
$newsIntro->addAttribute('type', 'latest');
Header('Content-type: text/xml');
echo $newsXML->asXML();
?>

Output

<?xml version="1.0"?>
<news newsPagePrefix="value goes here">
    <content type="latest"/>
</news>

Have fun.

What is the difference between ApplicationContext and WebApplicationContext in Spring MVC?

Web application context, specified by the WebApplicationContext interface, is a Spring application context for a web applications. It has all the properties of a regular Spring application context, given that the WebApplicationContext interface extends the ApplicationContext interface, and add a method for retrieving the standard Servlet API ServletContext for the web application.

In addition to the standard Spring bean scopes singleton and prototype, there are three additional scopes available in a web application context:

  • request - scopes a single bean definition to the lifecycle of a single HTTP request; that is, each HTTP request has its own instance of a bean created off the back of a single bean definition
  • session - scopes a single bean definition to the lifecycle of an HTTP Session
  • application - scopes a single bean definition to the lifecycle of a ServletContext

Javascript Array.sort implementation?

After some more research, it appears, for Mozilla/Firefox, that Array.sort() uses mergesort. See the code here.

How do I use FileSystemObject in VBA?

These guys have excellent examples of how to use the filesystem object http://www.w3schools.com/asp/asp_ref_filesystem.asp

<%
dim fs,fname
set fs=Server.CreateObject("Scripting.FileSystemObject")
set fname=fs.CreateTextFile("c:\test.txt",true)
fname.WriteLine("Hello World!")
fname.Close
set fname=nothing
set fs=nothing
%> 

How to clear File Input

Another solution if you want to be certain that this is cross-browser capable is to remove() the tag and then append() or prepend() or in some other way re-add a new instance of the input tag with the same attributes.

<form method="POST" enctype="multipart/form-data">
<label for="fileinput">
 <input type="file" name="fileinput" id="fileinput" />
</label>
</form>

$("#fileinput").remove();
$("<input>")
  .attr({
    type: 'file',
    id: 'fileinput',
    name: 'fileinput'
    })
  .appendTo($("label[for='fileinput']"));

Send array with Ajax to PHP script

If you have been trying to send a one dimentional array and jquery was converting it to comma separated values >:( then follow the code below and an actual array will be submitted to php and not all the comma separated bull**it.

Say you have to attach a single dimentional array named myvals.

jQuery('#someform').on('submit', function (e) {
    e.preventDefault();
    var data = $(this).serializeArray();

    var myvals = [21, 52, 13, 24, 75]; // This array could come from anywhere you choose 
    for (i = 0; i < myvals.length; i++) {
        data.push({
            name: "myvals[]", // These blank empty brackets are imp!
            value: myvals[i]
        });
    }

jQuery.ajax({
    type: "post",
    url: jQuery(this).attr('action'),
    dataType: "json",
    data: data, // You have to just pass our data variable plain and simple no Rube Goldberg sh*t.
    success: function (r) {
...

Now inside php when you do this

print_r($_POST);

You will get ..

Array
(
    [someinputinsidetheform] => 023
    [anotherforminput] => 111
    [myvals] => Array
        (
            [0] => 21
            [1] => 52
            [2] => 13
            [3] => 24
            [4] => 75
        )
)

Pardon my language, but there are hell lot of Rube-Goldberg solutions scattered all over the web and specially on SO, but none of them are elegant or solve the problem of actually posting a one dimensional array to php via ajax post. Don't forget to spread this solution.

How to get a value from a cell of a dataframe?

These are fast access for scalars

In [15]: df = pandas.DataFrame(numpy.random.randn(5,3),columns=list('ABC'))

In [16]: df
Out[16]: 
          A         B         C
0 -0.074172 -0.090626  0.038272
1 -0.128545  0.762088 -0.714816
2  0.201498 -0.734963  0.558397
3  1.563307 -1.186415  0.848246
4  0.205171  0.962514  0.037709

In [17]: df.iat[0,0]
Out[17]: -0.074171888537611502

In [18]: df.at[0,'A']
Out[18]: -0.074171888537611502

How to check if a column exists before adding it to an existing table in PL/SQL?

All the metadata about the columns in Oracle Database is accessible using one of the following views.

user_tab_cols; -- For all tables owned by the user

all_tab_cols ; -- For all tables accessible to the user

dba_tab_cols; -- For all tables in the Database.

So, if you are looking for a column like ADD_TMS in SCOTT.EMP Table and add the column only if it does not exist, the PL/SQL Code would be along these lines..

DECLARE
  v_column_exists number := 0;  
BEGIN
  Select count(*) into v_column_exists
    from user_tab_cols
    where upper(column_name) = 'ADD_TMS'
      and upper(table_name) = 'EMP';
      --and owner = 'SCOTT --*might be required if you are using all/dba views

  if (v_column_exists = 0) then
      execute immediate 'alter table emp add (ADD_TMS date)';
  end if;
end;
/

If you are planning to run this as a script (not part of a procedure), the easiest way would be to include the alter command in the script and see the errors at the end of the script, assuming you have no Begin-End for the script..

If you have file1.sql

alter table t1 add col1 date;
alter table t1 add col2 date;
alter table t1 add col3 date;

And col2 is present,when the script is run, the other two columns would be added to the table and the log would show the error saying "col2" already exists, so you should be ok.

Node.js create folder or use existing

Just as a newer alternative to Teemu Ikonen's answer, which is very simple and easily readable, is to use the ensureDir method of the fs-extra package.

It can not only be used as a blatant replacement for the built in fs module, but also has a lot of other functionalities in addition to the functionalities of the fs package.

The ensureDir method, as the name suggests, ensures that the directory exists. If the directory structure does not exist, it is created. Like mkdir -p. Not just the end folder, instead the entire path is created if not existing already.

the one provided above is the async version of it. It also has a synchronous method to perform this in the form of the ensureDirSync method.

Modify SVG fill color when being served as Background-Image

One way to do this is to serve your svg from some server side mechanism. Simply create a resource server side that outputs your svg according to GET parameters, and you serve it on a certain url.

Then you just use that url in your css.

Because as a background img, it isn't part of the DOM and you can't manipulate it. Another possibility would be to use it regularly, embed it in a page in a normal way, but position it absolutely, make it full width & height of a page and then use z-index css property to put it behind all the other DOM elements on a page.

Check if date is in the past Javascript

function isPrevDate() {
    alert("startDate is " + Startdate);
    if(Startdate.length != 0 && Startdate !='') {
        var start_date = Startdate.split('-');
        alert("Input date: "+ start_date);
        start_date=start_date[1]+"/"+start_date[2]+"/"+start_date[0];
        alert("start date arrray format " + start_date);
        var a = new Date(start_date);
        //alert("The date is a" +a);
        var today = new Date();
        var day = today.getDate();
        var mon = today.getMonth()+1;
        var year = today.getFullYear();
        today = (mon+"/"+day+"/"+year);
        //alert(today);
        var today = new Date(today);
        alert("Today: "+today.getTime());
        alert("a : "+a.getTime());
        if(today.getTime() > a.getTime() )
        {
            alert("Please select Start date in range");
            return false;
        } else {
            return true;
        }
    }
}

How to fill in form field, and submit, using javascript?

You can try something like this:

    <script type="text/javascript">
        function simulateLogin(userName)
        {
            var userNameField = document.getElementById("username");
            userNameField.value = userName;
            var goButton = document.getElementById("go");
            goButton.click();
        }

        simulateLogin("testUser");
</script>

Event when window.location.href changes

Well there is 2 ways to change the location.href. Either you can write location.href = "y.html", which reloads the page or can use the history API which does not reload the page. I experimented with the first a lot recently.

If you open a child window and capture the load of the child page from the parent window, then different browsers behave very differently. The only thing that is common, that they remove the old document and add a new one, so for example adding readystatechange or load event handlers to the old document does not have any effect. Most of the browsers remove the event handlers from the window object too, the only exception is Firefox. In Chrome with Karma runner and in Firefox you can capture the new document in the loading readyState if you use unload + next tick. So you can add for example a load event handler or a readystatechange event handler or just log that the browser is loading a page with a new URI. In Chrome with manual testing (probably GreaseMonkey too) and in Opera, PhantomJS, IE10, IE11 you cannot capture the new document in the loading state. In those browsers the unload + next tick calls the callback a few hundred msecs later than the load event of the page fires. The delay is typically 100 to 300 msecs, but opera simetime makes a 750 msec delay for next tick, which is scary. So if you want a consistent result in all browsers, then you do what you want to after the load event, but there is no guarantee the location won't be overridden before that.

var uuid = "win." + Math.random();
var timeOrigin = new Date();
var win = window.open("about:blank", uuid, "menubar=yes,location=yes,resizable=yes,scrollbars=yes,status=yes");


var callBacks = [];
var uglyHax = function (){
    var done = function (){
        uglyHax();
        callBacks.forEach(function (cb){
            cb();
        });
    };
    win.addEventListener("unload", function unloadListener(){
        win.removeEventListener("unload", unloadListener); // Firefox remembers, other browsers don't
        setTimeout(function (){
            // IE10, IE11, Opera, PhantomJS, Chrome has a complete new document at this point
            // Chrome on Karma, Firefox has a loading new document at this point
            win.document.readyState; // IE10 and IE11 sometimes fails if I don't access it twice, idk. how or why
            if (win.document.readyState === "complete")
                done();
            else
                win.addEventListener("load", function (){
                    setTimeout(done, 0);
                });
        }, 0);
    });
};
uglyHax();


callBacks.push(function (){
    console.log("cb", win.location.href, win.document.readyState);
    if (win.location.href !== "http://localhost:4444/y.html")
        win.location.href = "http://localhost:4444/y.html";
    else
        console.log("done");
});
win.location.href = "http://localhost:4444/x.html";

If you run your script only in Firefox, then you can use a simplified version and capture the document in a loading state, so for example a script on the loaded page cannot navigate away before you log the URI change:

var uuid = "win." + Math.random();
var timeOrigin = new Date();
var win = window.open("about:blank", uuid, "menubar=yes,location=yes,resizable=yes,scrollbars=yes,status=yes");


var callBacks = [];
win.addEventListener("unload", function unloadListener(){
    setTimeout(function (){
        callBacks.forEach(function (cb){
            cb();
        });
    }, 0);
});


callBacks.push(function (){
    console.log("cb", win.location.href, win.document.readyState);
    // be aware that the page is in loading readyState, 
    // so if you rewrite the location here, the actual page will be never loaded, just the new one
    if (win.location.href !== "http://localhost:4444/y.html")
        win.location.href = "http://localhost:4444/y.html";
    else
        console.log("done");
});
win.location.href = "http://localhost:4444/x.html";

If we are talking about single page applications which change the hash part of the URI, or use the history API, then you can use the hashchange and the popstate events of the window respectively. Those can capture even if you move in history back and forward until you stay on the same page. The document does not changes by those and the page is not really reloaded.

How to list all properties of a PowerShell object

The most succinct way to do this is:

Get-WmiObject -Class win32_computersystem -Property *

Comparing strings in C# with OR in an if statement

use if (testString.Equals(testString2)).

How to install JDK 11 under Ubuntu?

sudo apt-get install openjdk-11-jdk

after this, try

java -version

to make sure java version is 1.11.x, if found old one or different, check below command to see the available jdks,

sudo update-java-alternatives --list

you should see something like below,

java-1.11.0-openjdk-amd64 1111 /usr/lib/jvm/java-1.11.0-openjdk-amd64

java-1.8.0-openjdk-amd64 1081 /usr/lib/jvm/java-1.8.0-openjdk-amd64

you can see java 1.11 available from above list, use below command to set java 11 to default,

sudo update-alternatives --config java

for above command, you will get something like below and also, will ask for an option to set,

There are 3 choices for the alternative java (providing /usr/bin/java).

Selection Path Priority Status


0 /usr/lib/jvm/java-11-openjdk-amd64/bin/java 1111 auto mode

1 /usr/lib/jvm/java-11-openjdk-amd64/bin/java 1111 manual mode

*2 /usr/lib/jvm/java-8-openjdk-amd64/jre/bin/java 1081 manual mode

3 /usr/lib/jvm/jdk1.8.0_211/bin/java 0 manual mode

Press to keep the current choice[*], or type selection number:

you can select desired selection number, my case it's 0

for javac,

sudo update-alternatives --config javac

will result something like below,

There are 3 choices for the alternative javac (providing /usr/bin/javac).

Selection Path Priority Status


0 /usr/lib/jvm/java-11-openjdk-amd64/bin/javac 1111 auto mode

1 /usr/lib/jvm/java-11-openjdk-amd64/bin/javac 1111 manual mode

*2 /usr/lib/jvm/java-8-openjdk-amd64/bin/javac 1081 manual mode
3 /usr/lib/jvm/jdk1.8.0_211/bin/javac 0 manual mode

Press to keep the current choice[*], or type selection number:

in my case, it's 0 again

after above steps, try

java -version

it will display something like below,

openjdk version "11.0.4" 2019-07-16

OpenJDK Runtime Environment (build 11.0.4+11-post-Ubuntu-1ubuntu218.04.3)

OpenJDK 64-Bit Server VM (build 11.0.4+11-post-Ubuntu-1ubuntu218.04.3, mixed > mode, sharing)

"inconsistent use of tabs and spaces in indentation"

The following trick has worked for me:

  1. Copy and paste the code in the notepad.
  2. Then from the notepad again select all and copy the code
  3. Paste in my views.py
  4. Select all the newly pasted code in the views.py and remove all the tabs by pressing shift+tab from the keyboard
  5. Now use the tab key again to use the proper indentation

keytool error bash: keytool: command not found

If the jre is installed on your machine properly then look for keytool in jre or in jre/bin

  1. to find where jre is installed, use this

    sudo find / -name jre

  2. Then look for keytool in path_to_jre or in path_to_jre/bin

  3. cd to keytool location

  4. then run ./keytool

  5. Make sure to add the the path to $PATH by

    export PATH=$PATH:location_to_keytool

  6. To make sure you got it right after this, run

    where keytool

  7. for future edit you bash or zshrc file and source it

Why does an image captured using camera intent gets rotated on some devices on Android?

I solved it using a different method. All you have to do is check if the width is greater than height

            Matrix rotationMatrix = new Matrix();
        if(finalBitmap.getWidth() >= finalBitmap.getHeight())
        {
            rotationMatrix.setRotate(-90);
        }
        else
        {
            rotationMatrix.setRotate(0);
        }

        Bitmap rotatedBitmap = Bitmap.createBitmap(finalBitmap,0,0,finalBitmap.getWidth(),finalBitmap.getHeight(),rotationMatrix,true);

Styling Password Fields in CSS

The problem is that (as of 2016), for the password field, Firefox and Internet Explorer use the character "Black Circle" (?), which uses the Unicode code point 25CF, but Chrome uses the character "Bullet" (•), which uses the Unicode code point 2022.

As you can see, even in the StackOverflow font the two characters have different sizes.

The font you're using, "Lucida Sans Unicode", has an even greater disparity between the sizes of these two characters, leading to you noticing the difference.

The simple solution is to use a font in which both characters have similar sizes.

The fix could thus be to use a default font of the browser, which should render the characters in the password field just fine:

input[type="password"] {
    font-family: caption;
}

angularjs getting previous route path

In your html :

<a href="javascript:void(0);" ng-click="go_back()">Go Back</a>

On your main controller :

$scope.go_back = function() { 
  $window.history.back();
};

When user click on Go Back link the controller function is called and it will go back to previous route.

Python: SyntaxError: non-keyword after keyword arg

To really get this clear, here's my for-beginners answer: You inputed the arguments in the wrong order.
A keyword argument has this style:

nullable=True, unique=False

A fixed parameter should be defined: True, False, etc. A non-keyword argument is different:

name="Ricardo", fruit="chontaduro" 

This syntax error asks you to first put name="Ricardo" and all of its kind (non-keyword) before those like nullable=True.

Mod in Java produces negative numbers

if b > 0:
    int mod = (mod = a % b) < 0 ? a + b : a;

Doesn't use the % operator twice.

Using jquery to get all checked checkboxes with a certain class name

I'm not sure if it helps for your particular case, and I'm not sure if in your case, the checkboxes you want to include only are all part of a single form or div or table, but you can always select all checkboxes inside a specific element. For example:

<ul id="selective">
 <li><input type="checkbox" value="..." /></li>
 <li><input type="checkbox" value="..." /></li>
 <li><input type="checkbox" value="..." /></li>
 <li><input type="checkbox" value="..." /></li>
</ul>

Then, using the following jQuery, it ONLY goes through the checkboxes within that UL with id="selective":

$('#selective input:checkbox').each(function () {
 var sThisVal = (this.checked ? $(this).val() : "");
});

How to query values from xml nodes?

SELECT  b.BatchID,
        x.XmlCol.value('(ReportHeader/OrganizationReportReferenceIdentifier)[1]','VARCHAR(100)') AS OrganizationReportReferenceIdentifier,
        x.XmlCol.value('(ReportHeader/OrganizationNumber)[1]','VARCHAR(100)') AS OrganizationNumber
FROM    Batches b
CROSS APPLY b.RawXml.nodes('/CasinoDisbursementReportXmlFile/CasinoDisbursementReport') x(XmlCol);

Demo: SQLFiddle

SQL TRUNCATE DATABASE ? How to TRUNCATE ALL TABLES

---- Remove Constraint ----
EXEC sp_MSForEachTable "ALTER TABLE ? NOCHECK CONSTRAINT all"

---- Delete Data ----
EXEC sp_MSForEachTable "DELETE FROM ?"

---- Add Constraint ----
EXEC sp_MSForEachTable "ALTER TABLE ? WITH CHECK CHECK CONSTRAINT all"

---- Reset Identity value ----
EXEC sp_MSForEachTable "DBCC CHECKIDENT ( '?', RESEED, 0)"

Ubuntu, how do you remove all Python 3 but not 2

First of all, don't try the following command as suggested by Germain above.

   `sudo apt-get remove 'python3.*'`

In Ubuntu, many software depends upon Python3 so if you will execute this command it will remove all of them as it happened with me. I found following answer useful to recover it.

https://askubuntu.com/questions/810854/i-deleted-package-python3-on-ubuntu-and-i-have-lost-dashboard-terminal-and-un

If you want to use different python versions for different projects then create virtual environments it will be very useful. refer to the following link to create virtual environments.

Creating Virtual Environment also helps in using Tensorflow and Keras in Jupyter Notebook.

https://linoxide.com/linux-how-to/setup-python-virtual-environment-ubuntu/

Controlling execution order of unit tests in Visual Studio

Here is a class that can be used to setup and run ordered tests independent of MS Ordered Tests framework for whatever reason--like not have to adjust mstest.exe arguments on a build machine, or mixing ordered with non-ordered in a class.

The original testing framework only sees the list of ordered tests as a single test so any init/cleanup like [TestInitalize()] Init() is only called before and after the entire set.

Usage:

        [TestMethod] // place only on the list--not the individuals
        public void OrderedStepsTest()
        {
            OrderedTest.Run(TestContext, new List<OrderedTest>
            {
                new OrderedTest ( T10_Reset_Database, false ),
                new OrderedTest ( T20_LoginUser1, false ),
                new OrderedTest ( T30_DoLoginUser1Task1, true ), // continue on failure
                new OrderedTest ( T40_DoLoginUser1Task2, true ), // continue on failure
                // ...
            });                
        }

Implementation:

using Microsoft.VisualStudio.TestTools.UnitTesting;
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;

namespace UnitTests.Utility
{    
    /// <summary>
    /// Define and Run a list of ordered tests. 
    /// 2016/08/25: Posted to SO by crokusek 
    /// </summary>    
    public class OrderedTest
    {
        /// <summary>Test Method to run</summary>
        public Action TestMethod { get; private set; }

        /// <summary>Flag indicating whether testing should continue with the next test if the current one fails</summary>
        public bool ContinueOnFailure { get; private set; }

        /// <summary>Any Exception thrown by the test</summary>
        public Exception ExceptionResult;

        /// <summary>
        /// Constructor
        /// </summary>
        /// <param name="testMethod"></param>
        /// <param name="continueOnFailure">True to continue with the next test if this test fails</param>
        public OrderedTest(Action testMethod, bool continueOnFailure = false)
        {
            TestMethod = testMethod;
            ContinueOnFailure = continueOnFailure;
        }

        /// <summary>
        /// Run the test saving any exception within ExceptionResult
        /// Throw to the caller only if ContinueOnFailure == false
        /// </summary>
        /// <param name="testContextOpt"></param>
        public void Run()
        {
            try
            {
                TestMethod();
            }
            catch (Exception ex)
            {
                ExceptionResult = ex;
                throw;
            }
        }

        /// <summary>
        /// Run a list of OrderedTest's
        /// </summary>
        static public void Run(TestContext testContext, List<OrderedTest> tests)
        {
            Stopwatch overallStopWatch = new Stopwatch();
            overallStopWatch.Start();

            List<Exception> exceptions = new List<Exception>();

            int testsAttempted = 0;
            for (int i = 0; i < tests.Count; i++)
            {
                OrderedTest test = tests[i];

                Stopwatch stopWatch = new Stopwatch();
                stopWatch.Start();

                testContext.WriteLine("Starting ordered test step ({0} of {1}) '{2}' at {3}...\n",
                    i + 1,
                    tests.Count,
                    test.TestMethod.Method,
                    DateTime.Now.ToString("G"));

                try
                {
                    testsAttempted++;
                    test.Run();
                }
                catch
                {
                    if (!test.ContinueOnFailure)
                        break;
                }
                finally
                {
                    Exception testEx = test.ExceptionResult;

                    if (testEx != null)  // capture any "continue on fail" exception
                        exceptions.Add(testEx);

                    testContext.WriteLine("\n{0} ordered test step {1} of {2} '{3}' in {4} at {5}{6}\n",
                        testEx != null ? "Error:  Failed" : "Successfully completed",
                        i + 1,
                        tests.Count,
                        test.TestMethod.Method,
                        stopWatch.ElapsedMilliseconds > 1000
                            ? (stopWatch.ElapsedMilliseconds * .001) + "s"
                            : stopWatch.ElapsedMilliseconds + "ms",
                        DateTime.Now.ToString("G"),
                        testEx != null
                            ? "\nException:  " + testEx.Message +
                                "\nStackTrace:  " + testEx.StackTrace +
                                "\nContinueOnFailure:  " + test.ContinueOnFailure
                            : "");
                }
            }

            testContext.WriteLine("Completed running {0} of {1} ordered tests with a total of {2} error(s) at {3} in {4}",
                testsAttempted,
                tests.Count,
                exceptions.Count,
                DateTime.Now.ToString("G"),
                overallStopWatch.ElapsedMilliseconds > 1000
                    ? (overallStopWatch.ElapsedMilliseconds * .001) + "s"
                    : overallStopWatch.ElapsedMilliseconds + "ms");

            if (exceptions.Any())
            {
                // Test Explorer prints better msgs with this hierarchy rather than using 1 AggregateException().
                throw new Exception(String.Join("; ", exceptions.Select(e => e.Message), new AggregateException(exceptions)));
            }
        }
    }
}

count distinct values in spreadsheet

=iferror(counta(unique(A1:A100))) counts number of unique cells from A1 to A100

How to control font sizes in pgf/tikz graphics in latex?

\begin{tikzpicture}

    \tikzstyle{every node}=[font=\small]

\end{tikzpicture}

will give you font size control on every node.

Synchronous XMLHttpRequest warning and <script>

Browsers now warn for the use of synchronous XHR. MDN says this was implemented recently:

Starting with Gecko 30.0 (Firefox 30.0 / Thunderbird 30.0 / SeaMonkey 2.27)

https://developer.mozilla.org/en-US/docs/Web/API/XMLHttpRequest/Synchronous_and_Asynchronous_Requests#Synchronous_request

Here's how the change got implemented in Firefox and Chromium:

As for Chrome people report this started happening somewhere around version 39. I'm not sure how to link a revision/changeset to a particular version of Chrome.

Yes, it happens when jQuery appends markup to the page including script tags that load external js files. You can reproduce it with something like this:

$('body').append('<script src="foo.js"></script>');

I guess jQuery will fix this in some future version. Until then we can either ignore it or use A. Wolff's suggestion above.

Handling null values in Freemarker

I think it works the other way

<#if object.attribute??>
   Do whatever you want....
</#if>

If object.attribute is NOT NULL, then the content will be printed.

Python if not == vs if !=

I want to expand on my readability comment above.

Again, I completely agree with readability overriding other (performance-insignificant) concerns.

What I would like to point out is the brain interprets "positive" faster than it does "negative". E.g., "stop" vs. "do not go" (a rather lousy example due to the difference in number of words).

So given a choice:

if a == b
    (do this)
else
    (do that)

is preferable to the functionally-equivalent:

if a != b
    (do that)
else
    (do this)

Less readability/understandability leads to more bugs. Perhaps not in initial coding, but the (not as smart as you!) maintenance changes...

No matching client found for package name (Google Analytics) - multiple productFlavors & buildTypes

Whenever you create or update package name Make sure your package name is exactly the same [Upper case and lower case matters]

Do below step.

1). Check applicationId in App level gradle file,

2). Check package_name in your google-services.json file,

3). Check package in your AndroidManifest file

and for full confirmation make sure that your working package directory name i.e.("com.example.app") is also the same.

EDIT [ Any one who is facing this issue in productFlavour scenario, go check out Droid Chris's Solution ]

jwt check if token expired

This is the answer if someone want to know

if (Date.now() >= exp * 1000) {
  return false;
}

ToString() function in Go

I prefer something like the following:

type StringRef []byte

func (s StringRef) String() string {
        return string(s[:])
}

…

// rather silly example, but ...
fmt.Printf("foo=%s\n",StringRef("bar"))

Error: EACCES: permission denied

Creating package.json using npm init solved my issue.

What does "both" mean in <div style="clear:both">

Clear:both gives you that space between them.

For example your code:

  <div style="float:left">Hello</div>
  <div style="float:right">Howdy dere pardner</div>

Will currently display as :

Hello  ...................   Howdy dere pardner

If you add the following to above snippet,

  <div style="clear:both"></div>

In between them it will display as:

Hello ................ 
                       Howdy dere pardner

giving you that space between hello and Howdy dere pardner.

Js fiiddle http://jsfiddle.net/Qk5vR/1/

How to append data to a json file?

You probably want to use a JSON list instead of a dictionary as the toplevel element.

So, initialize the file with an empty list:

with open(DATA_FILENAME, mode='w', encoding='utf-8') as f:
    json.dump([], f)

Then, you can append new entries to this list:

with open(DATA_FILENAME, mode='w', encoding='utf-8') as feedsjson:
    entry = {'name': args.name, 'url': args.url}
    feeds.append(entry)
    json.dump(feeds, feedsjson)

Note that this will be slow to execute because you will rewrite the full contents of the file every time you call add. If you are calling it in a loop, consider adding all the feeds to a list in advance, then writing the list out in one go.

Angles between two n-dimensional vectors in Python

import math

def dotproduct(v1, v2):
  return sum((a*b) for a, b in zip(v1, v2))

def length(v):
  return math.sqrt(dotproduct(v, v))

def angle(v1, v2):
  return math.acos(dotproduct(v1, v2) / (length(v1) * length(v2)))

Note: this will fail when the vectors have either the same or the opposite direction. The correct implementation is here: https://stackoverflow.com/a/13849249/71522

How to format a URL to get a file from Amazon S3?

Its actually formulated more like:

https://<bucket-name>.s3.amazonaws.com/<key>

See here

Selecting one row from MySQL using mysql_* API

use mysql_fetch_assoc to fetch the result at an associated array instead of mysql_fetch_array which returns a numeric indexed array.

Event detect when css property changed using Jquery

You can use jQuery's css function to test the CSS properties, eg. if ($('node').css('display') == 'block').

Colin is right, that there is no explicit event that gets fired when a specific CSS property gets changed. But you may be able to flip it around, and trigger an event that sets the display, and whatever else.

Also consider using adding CSS classes to get the behavior you want. Often you can add a class to a containing element, and use CSS to affect all elements. I often slap a class onto the body element to indicate that an AJAX response is pending. Then I can use CSS selectors to get the display I want.

Not sure if this is what you're looking for.

Extracting Ajax return data in jQuery

Change the .find to .filter...

Python class inherits object

Yes, this is a 'new style' object. It was a feature introduced in python2.2.

New style objects have a different object model to classic objects, and some things won't work properly with old style objects, for instance, super(), @property and descriptors. See this article for a good description of what a new style class is.

SO link for a description of the differences: What is the difference between old style and new style classes in Python?

How can I style the border and title bar of a window in WPF?

Those are "non-client" areas and are controlled by Windows. Here is the MSDN docs on the subject (the pertinent info is at the top).

Basically, you set your Window's WindowStyle="None", then build your own window interface. (similar question on SO)

Adding double quote delimiters into csv file

open powershell and run below command:

import-csv C:\Users\Documents\Weekly_Status.csv | export-csv C:\Users\Documents\Weekly_Status2.csv  -NoTypeInformation -Encoding UTF8

Is there a typescript List<> and/or Map<> class/library?

It's very easy to write that yourself, and that way you have more control over things.. As the other answers say, TypeScript is not aimed at adding runtime types or functionality.

Map:

class Map<T> {
    private items: { [key: string]: T };

    constructor() {
        this.items = {};
    }

    add(key: string, value: T): void {
        this.items[key] = value;
    }

    has(key: string): boolean {
        return key in this.items;
    }

    get(key: string): T {
        return this.items[key];
    }
}

List:

class List<T> {
    private items: Array<T>;

    constructor() {
        this.items = [];
    }

    size(): number {
        return this.items.length;
    }

    add(value: T): void {
        this.items.push(value);
    }

    get(index: number): T {
        return this.items[index];
    }
}

I haven't tested (or even tried to compile) this code, but it should give you a starting point.. you can of course then change what ever you want and add the functionality that YOU need...

As for your "special needs" from the List, I see no reason why to implement a linked list, since the javascript array lets you add and remove items.
Here's a modified version of the List to handle the get prev/next from the element itself:

class ListItem<T> {
    private list: List<T>;
    private index: number;

    public value: T;

    constructor(list: List<T>, value: T, index: number) {
        this.list = list;
        this.index = index;
        this.value = value;
    }

    prev(): ListItem<T> {
        return this.list.get(this.index - 1);
    }

    next(): ListItem<T> {
        return this.list.get(this.index + 1);   
    }
}

class List<T> {
    private items: Array<ListItem<T>>;

    constructor() {
        this.items = [];
    }

    size(): number {
        return this.items.length;
    }

    add(value: T): void {
        this.items.push(new ListItem<T>(this, value, this.size()));
    }

    get(index: number): ListItem<T> {
        return this.items[index];
    }
}

Here too you're looking at untested code..

Hope this helps.


Edit - as this answer still gets some attention

Javascript has a native Map object so there's no need to create your own:

let map = new Map();
map.set("key1", "value1");
console.log(map.get("key1")); // value1

Eclipse interface icons very small on high resolution screen in Windows 8.1

-SurfacePro3-

  • Download and unzip eclipse "32bit Version".
  • Run on "Windows XP mode".

Plot yerr/xerr as shaded region rather than error bars

This is basically the same answer provided by Evert, but extended to show-off some cool options of fill_between

enter image description here

from matplotlib import pyplot as pl
import numpy as np

pl.clf()
pl.hold(1)

x = np.linspace(0, 30, 100)
y = np.sin(x) * 0.5
pl.plot(x, y, '-k')


x = np.linspace(0, 30, 30)
y = np.sin(x/6*np.pi)
error = np.random.normal(0.1, 0.02, size=y.shape) +.1
y += np.random.normal(0, 0.1, size=y.shape)

pl.plot(x, y, 'k', color='#CC4F1B')
pl.fill_between(x, y-error, y+error,
    alpha=0.5, edgecolor='#CC4F1B', facecolor='#FF9848')

y = np.cos(x/6*np.pi)    
error = np.random.rand(len(y)) * 0.5
y += np.random.normal(0, 0.1, size=y.shape)
pl.plot(x, y, 'k', color='#1B2ACC')
pl.fill_between(x, y-error, y+error,
    alpha=0.2, edgecolor='#1B2ACC', facecolor='#089FFF',
    linewidth=4, linestyle='dashdot', antialiased=True)



y = np.cos(x/6*np.pi)  + np.sin(x/3*np.pi)  
error = np.random.rand(len(y)) * 0.5
y += np.random.normal(0, 0.1, size=y.shape)
pl.plot(x, y, 'k', color='#3F7F4C')
pl.fill_between(x, y-error, y+error,
    alpha=1, edgecolor='#3F7F4C', facecolor='#7EFF99',
    linewidth=0)



pl.show()

jQuery - hashchange event

What about using a different way instead of the hash event and listen to popstate like.

window.addEventListener('popstate', function(event)
{
    if(window.location.hash) {
            var hash = window.location.hash;
            console.log(hash);
    }
});

This method works fine in most browsers i have tried so far.

How do I get HTTP Request body content in Laravel?

I don't think you want the data from your Request, I think you want the data from your Response. The two are different. Also you should build your response correctly in your controller.

Looking at the class in edit #2, I would make it look like this:

class XmlController extends Controller
{
    public function index()
    {
        $content = Request::all();
        return Response::json($content);
    }
}

Once you've gotten that far you should check the content of your response in your test case (use print_r if necessary), you should see the data inside.

More information on Laravel responses here:

http://laravel.com/docs/5.0/responses

How do I write a Python dictionary to a csv file?

You are using DictWriter.writerows() which expects a list of dicts, not a dict. You want DictWriter.writerow() to write a single row.

You will also want to use DictWriter.writeheader() if you want a header for you csv file.

You also might want to check out the with statement for opening files. It's not only more pythonic and readable but handles closing for you, even when exceptions occur.

Example with these changes made:

import csv

my_dict = {"test": 1, "testing": 2}

with open('mycsvfile.csv', 'w') as f:  # You will need 'wb' mode in Python 2.x
    w = csv.DictWriter(f, my_dict.keys())
    w.writeheader()
    w.writerow(my_dict)

Which produces:

test,testing
1,2

UITableView with fixed section headers

to make UITableView sections header not sticky or sticky:

  1. change the table view's style - make it grouped for not sticky & make it plain for sticky section headers - do not forget: you can do it from storyboard without writing code. (click on your table view and change it is style from the right Side/ component menu)

  2. if you have extra components such as custom views or etc. please check the table view's margins to create appropriate design. (such as height of header for sections & height of cell at index path, sections)

sendUserActionEvent() is null

This has to do with having two buttons with the same ID in two different Activities, sometimes Android Studio can't find, You just have to give your button a new ID and re Build the Project

How do I diff the same file between two different commits on the same branch?

If you have configured the "difftool" you can use

git difftool revision_1:file_1 revision_2:file_2

Example: Comparing a file from its last commit to its previous commit on the same branch: Assuming that if you are in your project root folder

$git difftool HEAD:src/main/java/com.xyz.test/MyApp.java HEAD^:src/main/java/com.xyz.test/MyApp.java

You should have the following entries in your ~/.gitconfig or in project/.git/config file. Install the p4merge [This is my preferred diff and merge tool]

[merge]
    tool = p4merge
    keepBackup = false
[diff]
    tool = p4merge
    keepBackup = false
[difftool "p4merge"]
    path = C:/Program Files (x86)/Perforce/p4merge.exe
[mergetool]
    keepBackup = false
[difftool]
    keepBackup = false
[mergetool "p4merge"]
    path = C:/Program Files (x86)/Perforce/p4merge.exe
    cmd = p4merge.exe \"$BASE\" \"$LOCAL\" \"$REMOTE\" \"$MERGED\"

ModuleNotFoundError: What does it mean __main__ is not a package?

Just use the name of the main folder which the .py file is in.

from problem_set_02.p_02_paying_debt_off_in_a_year import compute_balance_after

How to extract a string using JavaScript Regex?

You need to use the m flag:

multiline; treat beginning and end characters (^ and $) as working over multiple lines (i.e., match the beginning or end of each line (delimited by \n or \r), not only the very beginning or end of the whole input string)

Also put the * in the right place:

"DATE:20091201T220000\r\nSUMMARY:Dad's birthday".match(/^SUMMARY\:(.*)$/gm);
//------------------------------------------------------------------^    ^
//-----------------------------------------------------------------------|

Get css top value as number not as string?

A slightly more practical/efficient plugin based on Ivan Castellanos' answer (which was based on M4N's answer). Using || 0 will convert Nan to 0 without the testing step.

I've also provided float and int variations to suit the intended use:

jQuery.fn.cssInt = function (prop) {
    return parseInt(this.css(prop), 10) || 0;
};

jQuery.fn.cssFloat = function (prop) {
    return parseFloat(this.css(prop)) || 0;
};

Usage:

$('#elem').cssInt('top');    // e.g. returns 123 as an int
$('#elem').cssFloat('top');  // e.g. Returns 123.45 as a float

Test fiddle on http://jsfiddle.net/TrueBlueAussie/E5LTu/

How to I say Is Not Null in VBA

Use Not IsNull(Fields!W_O_Count.Value)

Graphviz: How to go from .dot to a graph?

You can use the VS code and install the Graphviz extension or,

  1. Install Graphviz from https://graphviz.gitlab.io/_pages/Download/Download_windows.html
  2. Add C:\Program Files (x86)\Graphviz2.38\bin (or your_installation_path/ bin) to your system variable PATH
  3. Open cmd and go to the dir where you saved the .dot file
  4. Use the command dot music-recommender.dot -Tpng -o image.png

enter image description here

How to change the size of the font of a JLabel to take the maximum size

Source Code for Label - How to change Color and Font (in Netbeans)

jLabel1.setFont(new Font("Serif", Font.BOLD, 12));


jLabel1.setForeground(Color.GREEN);

Avoid trailing zeroes in printf()

Your code rounds to three decimal places due to the ".3" before the f

printf("%1.3f", 359.01335);
printf("%1.3f", 359.00999);

Thus if you the second line rounded to two decimal places, you should change it to this:

printf("%1.3f", 359.01335);
printf("%1.2f", 359.00999);

That code will output your desired results:

359.013
359.01

*Note this is assuming you already have it printing on separate lines, if not then the following will prevent it from printing on the same line:

printf("%1.3f\n", 359.01335);
printf("%1.2f\n", 359.00999);

The Following program source code was my test for this answer

#include <cstdio>

int main()
{

    printf("%1.3f\n", 359.01335);
    printf("%1.2f\n", 359.00999);

    while (true){}

    return 0;

}

size of struct in C

As mentioned, the C compiler will add padding for alignment requirements. These requirements often have to do with the memory subsystem. Some types of computers can only access memory lined up to some 'nice' value, like 4 bytes. This is often the same as the word length. Thus, the C compiler may align fields in your structure to this value to make them easier to access (e.g., 4 byte values should be 4 byte aligned) Further, it may pad the bottom of the structure to line up data which follows the structure. I believe there are other reasons as well. More info can be found at this wikipedia page.

How to check if Location Services are enabled?

To get current Geo location in android google maps,you should turn on your device location option.To check whether the location is on or not,you can simple call this method from your onCreate() method.

private void checkGPSStatus() {
    LocationManager locationManager = null;
    boolean gps_enabled = false;
    boolean network_enabled = false;
    if ( locationManager == null ) {
        locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
    }
    try {
        gps_enabled = locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER);
    } catch (Exception ex){}
    try {
        network_enabled = locationManager.isProviderEnabled(LocationManager.NETWORK_PROVIDER);
    } catch (Exception ex){}
    if ( !gps_enabled && !network_enabled ){
        AlertDialog.Builder dialog = new AlertDialog.Builder(MyActivity.this);
        dialog.setMessage("GPS not enabled");
        dialog.setPositiveButton("Ok", new DialogInterface.OnClickListener() {

            @Override
            public void onClick(DialogInterface dialog, int which) {
                //this will navigate user to the device location settings screen
                Intent intent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
                startActivity(intent);
            }
        });
        AlertDialog alert = dialog.create();
        alert.show();
    }
}

Python list sort in descending order

This will give you a sorted version of the array.

sorted(timestamps, reverse=True)

If you want to sort in-place:

timestamps.sort(reverse=True)

Get model's fields in Django

How about this one.

fields = Model._meta.fields

How to emit an event from parent to child?

Using RxJs, you can declare a Subject in your parent component and pass it as Observable to child component, child component just need to subscribe to this Observable.

Parent-Component

eventsSubject: Subject<void> = new Subject<void>();

emitEventToChild() {
  this.eventsSubject.next();
}

Parent-HTML

<child [events]="eventsSubject.asObservable()"> </child>    

Child-Component

private eventsSubscription: Subscription;

@Input() events: Observable<void>;

ngOnInit(){
  this.eventsSubscription = this.events.subscribe(() => doSomething());
}

ngOnDestroy() {
  this.eventsSubscription.unsubscribe();
}

How to add New Column with Value to the Existing DataTable?

Add the column and update all rows in the DataTable, for example:

DataTable tbl = new DataTable();
tbl.Columns.Add(new DataColumn("ID", typeof(Int32)));
tbl.Columns.Add(new DataColumn("Name", typeof(string)));
for (Int32 i = 1; i <= 10; i++) {
    DataRow row = tbl.NewRow();
    row["ID"] = i;
    row["Name"] = i + ". row";
    tbl.Rows.Add(row);
}
DataColumn newCol = new DataColumn("NewColumn", typeof(string));
newCol.AllowDBNull = true;
tbl.Columns.Add(newCol);
foreach (DataRow row in tbl.Rows) {
    row["NewColumn"] = "You DropDownList value";
}
//if you don't want to allow null-values'
newCol.AllowDBNull = false;

How do you get a query string on Flask?

This can be done using request.args.get(). For example if your query string has a field date, it can be accessed using

date = request.args.get('date')

Don't forget to add "request" to list of imports from flask, i.e.

from flask import request

How to display my application's errors in JSF?

JSF is a beast. I may be missing something, but I used to solve similar problems by saving the desired message to a property of the bean, and then displaying the property via an outputText:

<h:outputText
    value="#{CreateNewPasswordBean.errorMessage}"
    render="#{CreateNewPasswordBean.errorMessage != null}" />

I want to remove double quotes from a String

If the string is guaranteed to have one quote (or any other single character) at beginning and end which you'd like to remove:

str = str.slice(1, -1);

slice has much less overhead than a regular expression.

Python Create unix timestamp five minutes in the future

This is what you need:

import time
import datetime
n = datetime.datetime.now()
unix_time = time.mktime(n.timetuple())

How to link a folder with an existing Heroku app

Two things to take care while setting up a new deployment System for old App

1. To check your app access to Heroku (especially the app)

heroku apps

it will list the apps you have access to if you set up for the first time, you probably need to

heroku keys:add

2. Then set up your git remote

For already created Heroku app, you can easily add a remote to your local repository with the heroku git: remote command. All you need is your Heroku app’s name:

heroku git:remote -a appName

you can also rename your remotes with the git remote rename command:

git remote rename heroku heroku-dev(you desired app name)

then You can use the git remote command to confirm that a remote been set for your app

 git remote -v

Why XML-Serializable class need a parameterless constructor

The answer is: for no good reason whatsoever.

Contrary to its name, the XmlSerializer class is used not only for serialization, but also for deserialization. It performs certain checks on your class to make sure that it will work, and some of those checks are only pertinent to deserialization, but it performs them all anyway, because it does not know what you intend to do later on.

The check that your class fails to pass is one of the checks that are only pertinent to deserialization. Here is what happens:

  • During deserialization, the XmlSerializer class will need to create instances of your type.

  • In order to create an instance of a type, a constructor of that type needs to be invoked.

  • If you did not declare a constructor, the compiler has already supplied a default parameterless constructor, but if you did declare a constructor, then that's the only constructor available.

  • So, if the constructor that you declared accepts parameters, then the only way to instantiate your class is by invoking that constructor which accepts parameters.

  • However, XmlSerializer is not capable of invoking any constructor except a parameterless constructor, because it does not know what parameters to pass to constructors that accept parameters. So, it checks to see if your class has a parameterless constructor, and since it does not, it fails.

So, if the XmlSerializer class had been written in such a way as to only perform the checks pertinent to serialization, then your class would pass, because there is absolutely nothing about serialization that makes it necessary to have a parameterless constructor.

As others have already pointed out, the quick solution to your problem is to simply add a parameterless constructor. Unfortunately, it is also a dirty solution, because it means that you cannot have any readonly members initialized from constructor parameters.

In addition to all this, the XmlSerializer class could have been written in such a way as to allow even deserialization of classes without parameterless constructors. All it would take would be to make use of "The Factory Method Design Pattern" (Wikipedia). From the looks of it, Microsoft decided that this design pattern is far too advanced for DotNet programmers, who apparently should not be unnecessarily confused with such things. So, DotNet programmers should better stick to parameterless constructors, according to Microsoft.

Delete cookie by name?

//if passed exMins=0 it will delete as soon as it creates it.

function setCookie(cname, cvalue, exMins) {
    var d = new Date();
    d.setTime(d.getTime() + (exMins*60*1000));
    var expires = "expires="+d.toUTCString();  
    document.cookie = cname + "=" + cvalue + ";" + expires + ";path=/";
}

setCookie('cookieNameToDelete','',0) // this will delete the cookie.

'System.Reflection.TargetInvocationException' occurred in PresentationFramework.dll

If the radiobutton-checked event occurs before the content of the window is loaded fully, i.e. the ellipse is loaded fully, such an exception will be thrown. So check if the UI of the window is loaded (probably by Window_ContentRendered event, etc.).

Objective-C - Remove last character from string

The documentation is your friend, NSString supports a call substringWithRange that can shorten the string that you have an return the shortened String. You cannot modify an instance of NSString it is immutable. If you have an NSMutableString is has a method called deleteCharactersInRange that can modify the string in place

...
NSRange r;
r.location = 0;
r.size = [mutable length]-1;
NSString* shorted = [stringValue substringWithRange:r];
...

How to use RecyclerView inside NestedScrollView?

nestedScrollView.setNestedScrollingEnabled(true);

mRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
        @Override
        public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
            super.onScrolled(recyclerView, dx, dy);
            //...
        }
    });


<androidx.core.widget.NestedScrollView
    android:id="@+id/nested"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fillViewport="true"
    android:layout_below="@id/appBarLayout_orders"
    app:layout_behavior="@string/appbar_scrolling_view_behavior"> 

    <androidx.constraintlayout.widget.ConstraintLayout ...

        <androidx.recyclerview.widget.RecyclerView
            android:id="@+id/recycler"
            android:layout_width="match_parent"
            android:layout_height="0dp"
            app:layout_constraintTop_toTopOf="parent"
            app:layout_constraintBottom_toBottomOf="parent"/>

How to set the image from drawable dynamically in android?

This works for me (dont use the extension of the image, just the name):

String imagename = "myImage";
int res = getResources().getIdentifier(imagename, "drawable", this.getPackageName());
imageview= (ImageView)findViewById(R.id.imageView);
imageview.setImageResource(res);

Parsing JSON giving "unexpected token o" error

I had the same problem when I submitted data using jQuery AJAX:

$.ajax({
   url:...
   success:function(data){
      //server response's data is JSON
      //I use jQuery's parseJSON method 
      $.parseJSON(data);//it's ERROR
   }
});

If the response is JSON, and you use this method, the data you get is a JavaScript object, but if you use dataType:"text", data is a JSON string. Then the use of $.parseJSON is okay.

Is there an easy way to reload css without reloading the page?

Yes, reload the css tag. And remember to make the new url unique (usually by appending a random query parameter). I have code to do this but not with me right now. Will edit later...

edit: too late... harto and nickf beat me to it ;-)

Fixed positioned div within a relative parent div

you can fix the wrapper using absolute positioning. and the give inside div a fixed position.

.wrapper{
 position:absolute;
 left:10%;// or some valve in px
 top:10%; // or some valve in px
 }

and div inside that

.wrapper .fixed-element{ 
position:fixed;
width:100%;
height:100%;
margin-left:auto; // to center this div inside at center give auto margin
margin-right:auto;
}

try this It might work for you

How can I right-align text in a DataGridView column?

I know this is old, but for those surfing this question, the answer by MUG4N will align all columns that use the same defaultcellstyle. I'm not using autogeneratecolumns so that is not acceptable. Instead I used:

e.Column.DefaultCellStyle = new DataGridViewCellStyle(e.Column.DefaultCellStyle);
e.Column.DefaultCellStyle.Alignment = DataGridViewContentAlignment.MiddleRight;

In this case e is from:

Grd_ColumnAdded(object sender, DataGridViewColumnEventArgs e)  

Check if a file exists locally using JavaScript only

Try this:

window.onclick=(function(){
  try {
    var file = window.open("file://mnt/sdcard/download/Click.ogg");
    setTimeout('file.close()', 100);
    setTimeout("alert('Audio file found. Have a nice day!');", 101);
  } catch(err) {
    var wantstodl=confirm("Warning:\n the file, Click.ogg is not found.\n do you want to download it?\n "+err.message);
    if (wantstodl) {
      window.open("https://www.dropbox.com/s/qs9v6g2vru32xoe/Click.ogg?dl=1"); //downloads the audio file
    }
  }
});

Create a sample login page using servlet and JSP?

As I can see, you are comparing the message with the empty string using ==.

Its very hard to write the full code, but I can tell the flow of code - first, create db class & method inide that which will return the connection. second, create a servelet(ex-login.java) & import that db class onto that servlet. third, create instance of imported db class with the help of new operator & call the connection method of that db class. fourth, creaet prepared statement & execute statement & put this code in try catch block for exception handling.Use if-else condition in the try block to navigate your login page based on success or failure.

I hope, it will help you. If any problem, then please revert.

Nikhil Pahariya

Among $_REQUEST, $_GET and $_POST which one is the fastest?

I'd suggest using $_POST and $_GET explicitly.

Using $_REQUEST should be unnecessary with proper site design anyway, and it comes with some downsides like leaving you open to easier CSRF/XSS attacks and other silliness that comes from storing data in the URL.

The speed difference should be minimal either way.

How to obtain values of request variables using Python and Flask

You can get posted form data from request.form and query string data from request.args.

myvar =  request.form["myvar"]
myvar = request.args["myvar"]

How do I load an HTTP URL with App Transport Security enabled in iOS 9?

I have solved as plist file.

  1. Add a NSAppTransportSecurity : Dictionary.
  2. Add Subkey named " NSAllowsArbitraryLoads " as Boolean : YES

enter image description here