Programs & Examples On #Rackspace cloud

The Rackspace Cloud is a set of cloud computing products and services billed on a utility computing basis from the US-based company Rackspace. Offerings include web application hosting or platform as a service ("Cloud Sites"), Cloud Storage ("Cloud Files"), virtual private server ("Cloud Servers"), load balancers, databases, backup, and monitoring.

What are native methods in Java and where should they be used?

What are native methods in Java and where should they be used?

Once you see a small example, it becomes clear:

Main.java:

public class Main {
    public native int intMethod(int i);
    public static void main(String[] args) {
        System.loadLibrary("Main");
        System.out.println(new Main().intMethod(2));
    }
}

Main.c:

#include <jni.h>
#include "Main.h"

JNIEXPORT jint JNICALL Java_Main_intMethod(
    JNIEnv *env, jobject obj, jint i) {
  return i * i;
}

Compile and run:

javac Main.java
javah -jni Main
gcc -shared -fpic -o libMain.so -I${JAVA_HOME}/include \
  -I${JAVA_HOME}/include/linux Main.c
java -Djava.library.path=. Main

Output:

4

Tested on Ubuntu 14.04 with Oracle JDK 1.8.0_45.

So it is clear that it allows you to:

  • call a compiled dynamically loaded library (here written in C) with arbitrary assembly code from Java
  • and get results back into Java

This could be used to:

  • write faster code on a critical section with better CPU assembly instructions (not CPU portable)
  • make direct system calls (not OS portable)

with the tradeoff of lower portability.

It is also possible for you to call Java from C, but you must first create a JVM in C: How to call Java functions from C++?

Example on GitHub for you to play with.

Unzip files programmatically in .net

I found out about this one (Unzip package on NuGet) today, since I ran into a hard bug in DotNetZip, and I realized there hasn't been really that much work done on DotNetZip for the last two years.

The Unzip package is lean, and it did the job for me - it didn't have the bug that DotNetZip had. Also, it was a reasonably small file, relying upon the Microsoft BCL for the actual decompression. I could easily make adjustments which I needed (to be able to keep track of the progress while decompressing). I recommend it.

How to downgrade python from 3.7 to 3.6

pyenv can be used in Linux/MacOS for python version management. pyenv-win is the fork of pyenv which can be used on Windows.

Installation

MacOS

Tested on Mac Catalina

  1. Install pyenv.

    brew install pyenv
    
  2. Add following to your shell config file:

    • .bashrc/.bash_profile - For Bash
    • .zshrc - For Zsh
    export PYENV_ROOT="$HOME/.pyenv"
    export PATH="$PYENV_ROOT/bin:$PATH"
    eval "$(pyenv init -)"
    
  3. Restart your shell. Start a new shell or run exec "$SHELL" in your current shell.

Linux / Windows on Linux Subsystem

Tested on Arch Linux

  1. Install pyenv on your system.

    curl https://pyenv.run | bash
    
  2. Follow same steps as in Step 2 and 3 of MacOS installation.

Windows

  1. Install pyenv-win on Windows.

    In Powershell

    pip install pyenv-win --target "$HOME\.pyenv"
    

    In cmd.exe

    pip install pyenv-win --target "%USERPROFILE%\.pyenv"
    
  2. Setup the environment variables using Powershell/Terminal.

    [System.Environment]::SetEnvironmentVariable('PYENV',$env:USERPROFILE + "\.pyenv\pyenv-win\","User")
    [System.Environment]::SetEnvironmentVariable('PYENV_HOME',$env:USERPROFILE + "\.pyenv\pyenv-win\","User")
    [System.Environment]::SetEnvironmentVariable('path', $HOME + "\.pyenv\pyenv-win\bin;" + $HOME + "\.pyenv\pyenv-win\shims;" + $env:Path,"User")
    
  3. Close and re-open your terminal. Run pyenv --version on the terminal.

    a. If the return value is the installed version of pyenv, then continue below. b. If you receive a command not found error, ensure the environment variables are properly set via the GUI: This PC ? Properties ? Advanced system settings ? Advanced ? Environment Variables... ? PATH c. If you receive a command not found error and you are using Visual Studio Code or another IDE with a built in terminal, restart it and try again.

  4. Run pyenv rehash from the home directory.

Usage

Check installed python versions

pyenv versions

Example

$ pyenv versions
* system (set by /home/souser/.pyenv/version)
  3.6.9

Installed a specific python version

pyenv install <version-number>

Uninstall an installed python version

pyenv uninstall <version-number>

Set a python version as system-wide python version

pyenv global <version-number> # <version-number> is the name assigned to your python in output of `pyenv versions`

Example

$ python --version
Python 3.9.1
$ pyenv global 3.6.9
$ python --version
Python 3.6.9
Set a python version for a directory and all it's sub-directories
pyenv local <version-number> # <version-number> is the name assigned to your python in output of `pyenv versions`

Example

~/tmp/temp$ python --version
Python 3.9.1
~/tmp/temp$ pyenv local 3.6.9
~/tmp/temp$ python --version
Python 3.6.9

For more details, you can check the Github repos : pyenv and pyenv-win.

How do I convert an enum to a list in C#?

Here is the way I love, using LINQ:

public class EnumModel
{
    public int Value { get; set; }
    public string Name { get; set; }
}

public enum MyEnum
{
    Name1=1,
    Name2=2,
    Name3=3
}

public class Test
{
        List<EnumModel> enums = ((MyEnum[])Enum.GetValues(typeof(MyEnum))).Select(c => new EnumModel() { Value = (int)c, Name = c.ToString() }).ToList();

        // A list of Names only, does away with the need of EnumModel 
        List<string> MyNames = ((MyEnum[])Enum.GetValues(typeof(MyEnum))).Select(c => c.ToString()).ToList();

        // A list of Values only, does away with the need of EnumModel 
        List<int> myValues = ((MyEnum[])Enum.GetValues(typeof(MyEnum))).Select(c => (int)c).ToList();

        // A dictionnary of <string,int>
        Dictionary<string,int> myDic = ((MyEnum[])Enum.GetValues(typeof(MyEnum))).ToDictionary(k => k.ToString(), v => (int)v);
}

Hope it helps

Is it bad to have my virtualenv directory inside my git repository?

I use pip freeze to get the packages I need into a requirements.txt file and add that to my repository. I tried to think of a way of why you would want to store the entire virtualenv, but I could not.

List rows after specific date

Simply put:

SELECT * 
FROM TABLE_NAME
WHERE
dob > '1/21/2012'

Where 1/21/2012 is the date and you want all data, including that date.

SELECT * 
FROM TABLE_NAME
WHERE
dob BETWEEN '1/21/2012' AND '2/22/2012'

Use a between if you're selecting time between two dates

Can not find module “@angular-devkit/build-angular”

This worked for me: Type npm audit fix in the commandline. Afterwards I was able to use ng serve --open again.

how to get the child node in div using javascript

If you give your table a unique id, its easier:

<div id="ctl00_ContentPlaceHolder1_Jobs_dlItems_ctl01_a"
    onmouseup="checkMultipleSelection(this,event);">
       <table id="ctl00_ContentPlaceHolder1_Jobs_dlItems_ctl01_a_table" 
              cellpadding="0" cellspacing="0" border="0" width="100%">
           <tr>
              <td style="width:50px; text-align:left;">09:15 AM</td>
              <td style="width:50px; text-align:left;">Item001</td>
              <td style="width:50px; text-align:left;">10</td>
              <td style="width:50px; text-align:left;">Address1</td>
              <td style="width:50px; text-align:left;">46545465</td>
              <td style="width:50px; text-align:left;">ref1</td>
           </tr>
       </table>
</div>


var multiselect = 
    document.getElementById(
               'ctl00_ContentPlaceHolder1_Jobs_dlItems_ctl01_a_table'
            ).rows[0].cells,
    timeXaddr = [multiselect[0].innerHTML, multiselect[2].innerHTML];

//=> timeXaddr now an array containing ['09:15 AM', 'Address1'];

Check if URL has certain string with PHP

$url = " www.domain.com/car/audi/";
if (strpos($url, "car")!==false){
    echo "Car here";
}
else {
   echo "No car here :(";
}

See strpos manual

PopupWindow $BadTokenException: Unable to add window -- token null is not valid

Use:

YourActivityName.this

Instead of:

getApplicationContext();

What is "pom" packaging in maven?

To simply answer your question when you do a mvn:install, maven will create a packaged artifact based on (packaging attribute in pom.xml), After you run your maven install you can find the file with .package extension

  • In target directory of the project workspace
  • Also where your maven 2 local repository is search for (.m2/respository) on your box, Your artifact is listed in .m2 repository under (groupId/artifactId/artifactId-version.packaging) directory
  • If you look under the directory you will find packaged extension file and also pom extension (pom extension is basically the pom.xml used to generate this package)
  • If your maven project is multi-module each module will two files as described above except for the top level project that will only have a pom

Android map v2 zoom to show all the markers

Google Map V2

The following solution works for Android Marshmallow 6 (API 23, API 24, API 25, API 26, API 27, API 28). It also works in Xamarin.

LatLngBounds.Builder builder = new LatLngBounds.Builder();

//the include method will calculate the min and max bound.
builder.include(marker1.getPosition());
builder.include(marker2.getPosition());
builder.include(marker3.getPosition());
builder.include(marker4.getPosition());

LatLngBounds bounds = builder.build();

int width = getResources().getDisplayMetrics().widthPixels;
int height = getResources().getDisplayMetrics().heightPixels;
int padding = (int) (width * 0.10); // offset from edges of the map 10% of screen

CameraUpdate cu = CameraUpdateFactory.newLatLngBounds(bounds, width, height, padding);

mMap.animateCamera(cu);

How to use Select2 with JSON via Ajax request?

In Version 4.0.2 slightly different Just in processResults and in result :

    processResults: function (data) {
        return {
            results: $.map(data.items, function (item) {
                return {
                    text: item.tag_value,
                    id: item.tag_id
                }
            })
        };
    }

You must add data.items in result. items is Json name :

{
  "items": [
    {"id": 1,"name": "Tetris","full_name": "s9xie/hed"},
    {"id": 2,"name": "Tetrisf","full_name": "s9xie/hed"}
  ]
}

How can I convert a DateTime to an int?

long n = long.Parse(date.ToString("yyyyMMddHHmmss"));

see Custom Date and Time Format Strings

How to output (to a log) a multi-level array in a format that is human-readable?

http://php.net/manual/en/function.print-r.php This function can be used to format output,

$output = print_r($array,1);

$output is a string variable, it can be logged like every other string. In pure php you can use trigger_error

Ex. trigger_error($output);

http://php.net/manual/en/function.trigger-error.php

if you need to format it also in html, you can use <pre> tag

Angular 2 Checkbox Two Way Data Binding

You must add name="selected" attribute to input element.

For example:

<div class="checkbox">
  <label>
    <input name="selected" [(ngModel)]="saveUsername.selected" type="checkbox">Save username
  </label>
</div>

How to use java.net.URLConnection to fire and handle HTTP requests?

Inspired by this and other questions on SO, I've created a minimal open source basic-http-client that embodies most of the techniques found here.

google-http-java-client is also a great open source resource.

"CASE" statement within "WHERE" clause in SQL Server 2008

Try the following:

select * From emp_master 
where emp_last_name= 
case emp_first_name 
 when 'test'    then 'test' 
 when 'Mr name' then 'name'
end

Twitter bootstrap float div right

You can assign the class name like text-center, left or right. The text will align accordingly to these class name. You don't need to make extra class name separately. These classes are built in BootStrap 3 and bootstrap 4.

Bootstrap 3

v3 Text Alignment Docs

<p class="text-left">Left aligned text.</p>
<p class="text-center">Center aligned text.</p>
<p class="text-right">Right aligned text.</p>
<p class="text-justify">Justified text.</p>
<p class="text-nowrap">No wrap text.</p>

Bootstrap 4

v4 Text Alignment Docs

<p class="text-xs-left">Left aligned text on all viewport sizes.</p>
<p class="text-xs-center">Center aligned text on all viewport sizes.</p>
<p class="text-xs-right">Right aligned text on all viewport sizes.</p>

<p class="text-sm-left">Left aligned text on viewports sized SM (small) or wider.</p>
<p class="text-md-left">Left aligned text on viewports sized MD (medium) or wider.</p>
<p class="text-lg-left">Left aligned text on viewports sized LG (large) or wider.</p>
<p class="text-xl-left">Left aligned text on viewports sized XL (extra-large) or wider.</p>

How to get the nvidia driver version from the command line?

Using nvidia-smi should tell you that:

bwood@mybox:~$ nvidia-smi 
Mon Oct 29 12:30:02 2012       
+------------------------------------------------------+                       
| NVIDIA-SMI 3.295.41   Driver Version: 295.41         |                       
|-------------------------------+----------------------+----------------------+
| Nb.  Name                     | Bus Id        Disp.  | Volatile ECC SB / DB |
| Fan   Temp   Power Usage /Cap | Memory Usage         | GPU Util. Compute M. |
|===============================+======================+======================|
| 0.  GeForce GTX 580           | 0000:25:00.0  N/A    |       N/A        N/A |
|  54%   70 C  N/A   N/A /  N/A |  25%  383MB / 1535MB |  N/A      Default    |
|-------------------------------+----------------------+----------------------|
| Compute processes:                                               GPU Memory |
|  GPU  PID     Process name                                       Usage      |
|=============================================================================|
|  0.           Not Supported                                                 |
+-----------------------------------------------------------------------------+

Http post and get request in angular 6

You can do a post/get using a library which allows you to use HttpClient with strongly-typed callbacks.

The data and the error are available directly via these callbacks.

The library is called angular-extended-http-client.

angular-extended-http-client library on GitHub

angular-extended-http-client library on NPM

Very easy to use.

Traditional approach

In the traditional approach you return Observable<HttpResponse<T>> from Service API. This is tied to HttpResponse.

With this approach you have to use .subscribe(x => ...) in the rest of your code.

This creates a tight coupling between the http layer and the rest of your code.

Strongly-typed callback approach

You only deal with your Models in these strongly-typed callbacks.

Hence, The rest of your code only knows about your Models.

Sample usage

The strongly-typed callbacks are

Success:

  • IObservable<T>
  • IObservableHttpResponse
  • IObservableHttpCustomResponse<T>

Failure:

  • IObservableError<TError>
  • IObservableHttpError
  • IObservableHttpCustomError<TError>

Add package to your project and in your app module

import { HttpClientExtModule } from 'angular-extended-http-client';

and in the @NgModule imports

  imports: [
    .
    .
    .
    HttpClientExtModule
  ],

Your Models


export class SearchModel {
    code: string;
}

//Normal response returned by the API.
export class RacingResponse {
    result: RacingItem[];
}

//Custom exception thrown by the API.
export class APIException {
    className: string;
}

Your Service

In your Service, you just create params with these callback types.

Then, pass them on to the HttpClientExt's get method.

import { Injectable, Inject } from '@angular/core'
import { SearchModel, RacingResponse, APIException } from '../models/models'
import { HttpClientExt, IObservable, IObservableError, ResponseType, ErrorType } from 'angular-extended-http-client';
.
.

@Injectable()
export class RacingService {

    //Inject HttpClientExt component.
    constructor(private client: HttpClientExt, @Inject(APP_CONFIG) private config: AppConfig) {

    }

    //Declare params of type IObservable<T> and IObservableError<TError>.
    //These are the success and failure callbacks.
    //The success callback will return the response objects returned by the underlying HttpClient call.
    //The failure callback will return the error objects returned by the underlying HttpClient call.
    searchRaceInfo(model: SearchModel, success: IObservable<RacingResponse>, failure?: IObservableError<APIException>) {
        let url = this.config.apiEndpoint;

        this.client.post<SearchModel, RacingResponse>(url, model, 
                                                      ResponseType.IObservable, success, 
                                                      ErrorType.IObservableError, failure);
    }
}

Your Component

In your Component, your Service is injected and the searchRaceInfo API called as shown below.

  search() {    


    this.service.searchRaceInfo(this.searchModel, response => this.result = response.result,
                                                  error => this.errorMsg = error.className);

  }

Both, response and error returned in the callbacks are strongly typed. Eg. response is type RacingResponse and error is APIException.

Adding new line of data to TextBox

If you use WinForms:

Use the AppendText(myTxt) method on the TextBox instead (.net 3.5+):

    private void button1_Click(object sender, EventArgs e)
    {
        string sent = chatBox.Text;

        displayBox.AppendText(sent);
        displayBox.AppendText(Environment.NewLine);

    }

Text in itself has typically a low memory footprint (you can say a lot within f.ex. 10kb which is "nothing"). The TextBox does not render all text that is in the buffer, only the visible part so you don't need to worry too much about lag. The slower operations are inserting text. Appending text is relatively fast.

If you need a more complex handling of the content you can use StringBuilder combined with the textbox. This will give you a very efficient way of handling text.

What's the difference between F5 refresh and Shift+F5 in Google Chrome browser?

Reload the current page:
F5
or
CTRL + R


Reload the current page, ignoring cached content (i.e. JavaScript files, images, etc.):
SHIFT + F5
or
CTRL + F5
or
CTRL + SHIFT + R

How can I find the latitude and longitude from address?

public void goToLocationFromAddress(String strAddress) {
    //Create coder with Activity context - this
    Geocoder coder = new Geocoder(this);
    List<Address> address;

    try {
        //Get latLng from String
        address = coder.getFromLocationName(strAddress, 5);

        //check for null
        if (address != null) {

            //Lets take first possibility from the all possibilities.
            try {
                Address location = address.get(0);
                LatLng latLng = new LatLng(location.getLatitude(), location.getLongitude());

                //Animate and Zoon on that map location
                mMap.moveCamera(CameraUpdateFactory.newLatLng(latLng));
                mMap.animateCamera(CameraUpdateFactory.zoomTo(15));
            } catch (IndexOutOfBoundsException er) {
                Toast.makeText(this, "Location isn't available", Toast.LENGTH_SHORT).show();
            }

        }


    } catch (IOException e) {
        e.printStackTrace();
    }
}

How to remove unused imports from Eclipse

Remove all unused import in eclipse:

Right click on the desired package then Source->Organize Imports. Or You can direct use the shortcut by pressing Ctrl+Shift+O

Work perfectly.

Printing everything except the first field with awk

The field separator in gawk (at least) can be a string as well as a character (it can also be a regex). If your data is consistent, then this will work:

awk -F "  " '{print $2,$1}' inputfile

That's two spaces between the double quotes.

Connect Bluestacks to Android Studio

Steps to connect Blue Stack with Android Studio

  1. Close Android Studio.
  2. Go to adb.exe location (default location: %LocalAppData%\Android\sdk\platform-tools)
  3. Run adb connect localhost:5555 from this location.
  4. Start Android Studio and you will get Blue Stack as emulator when you run your app.

What do <o:p> elements do anyway?

Couldn't find any official documentation (no surprise there) but according to this interesting article, those elements are injected in order to enable Word to convert the HTML back to fully compatible Word document, with everything preserved.

The relevant paragraph:

Microsoft added the special tags to Word's HTML with an eye toward backward compatibility. Microsoft wanted you to be able to save files in HTML complete with all of the tracking, comments, formatting, and other special Word features found in traditional DOC files. If you save a file in HTML and then reload it in Word, theoretically you don't loose anything at all.

This makes lots of sense.

For your specific question.. the o in the <o:p> means "Office namespace" so anything following the o: in a tag means "I'm part of Office namespace" - in case of <o:p> it just means paragraph, the equivalent of the ordinary <p> tag.

I assume that every HTML tag has its Office "equivalent" and they have more.

Reflection generic get field value

I post my solution in Kotlin, but it can work with java objects as well. I create a function extension so any object can use this function.

fun Any.iterateOverComponents() {

val fields = this.javaClass.declaredFields

fields.forEachIndexed { i, field ->

    fields[i].isAccessible = true
    // get value of the fields
    val value = fields[i].get(this)

    // print result
    Log.w("Msg", "Value of Field "
            + fields[i].name
            + " is " + value)
}}

Take a look at this webpage: https://www.geeksforgeeks.org/field-get-method-in-java-with-examples/

How to increase Neo4j's maximum file open limit (ulimit) in Ubuntu?

What you are doing will not work for root user. Maybe you are running your services as root and hence you don't get to see the change.

To increase the ulimit for root user you should replace the * by root. * does not apply for root user. Rest is the same as you did. I will re-quote it here.

Add the following lines to the file: /etc/security/limits.conf

root soft  nofile 40000

root hard  nofile 40000

And then add following line in the file: /etc/pam.d/common-session

session required pam_limits.so

This will update the ulimit for root user. As mentioned in comments, you may don't even have to reboot to see the change.

Calculate last day of month in JavaScript

var month = 0; // January
var d = new Date(2008, month + 1, 0);
alert(d); // last day in January

IE 6:                     Thu Jan 31 00:00:00 CST 2008
IE 7:                     Thu Jan 31 00:00:00 CST 2008
IE 8: Beta 2:             Thu Jan 31 00:00:00 CST 2008
Opera 8.54:               Thu, 31 Jan 2008 00:00:00 GMT-0600
Opera 9.27:               Thu, 31 Jan 2008 00:00:00 GMT-0600
Opera 9.60:               Thu Jan 31 2008 00:00:00 GMT-0600
Firefox 2.0.0.17:         Thu Jan 31 2008 00:00:00 GMT-0600 (Canada Central Standard Time)
Firefox 3.0.3:            Thu Jan 31 2008 00:00:00 GMT-0600 (Canada Central Standard Time)
Google Chrome 0.2.149.30: Thu Jan 31 2008 00:00:00 GMT-0600 (Canada Central Standard Time)
Safari for Windows 3.1.2: Thu Jan 31 2008 00:00:00 GMT-0600 (Canada Central Standard Time)

Output differences are due to differences in the toString() implementation, not because the dates are different.

Of course, just because the browsers identified above use 0 as the last day of the previous month does not mean they will continue to do so, or that browsers not listed will do so, but it lends credibility to the belief that it should work the same way in every browser.

DLL load failed error when importing cv2

(base) C:\WINDOWS\system32>conda install C:\Users\Todd\Downloads\opencv3-3.1.0-py35_0.tar.bz2

I ran this command from anaconda terminal after I downloaded the version from https://anaconda.org/menpo/opencv3/files

This is the only way I could get cv2 to work and I tried everything for two days.

Waiting till the async task finish its work

wait until this call is finish its executing

You will need to call AsyncTask.get() method for getting result back and make wait until doInBackground execution is not complete. but this will freeze Main UI thread if you not call get method inside a Thread.

To get result back in UI Thread start AsyncTask as :

String str_result= new RunInBackGround().execute().get();

How to register multiple implementations of the same interface in Asp.Net Core?

How about a service for services?

If we had an INamedService interface (with .Name property), we could write an IServiceCollection extension for .GetService(string name), where the extension would take that string parameter, and do a .GetServices() on itself, and in each returned instance, find the instance whose INamedService.Name matches the given name.

Like this:

public interface INamedService
{
    string Name { get; }
}

public static T GetService<T>(this IServiceProvider provider, string serviceName)
    where T : INamedService
{
    var candidates = provider.GetServices<T>();
    return candidates.FirstOrDefault(s => s.Name == serviceName);
}

Therefore, your IMyService must implement INamedService, but you'll get the key-based resolution you want, right?

To be fair, having to even have this INamedService interface seems ugly, but if you wanted to go further and make things more elegant, then a [NamedServiceAttribute("A")] on the implementation/class could be found by the code in this extension, and it'd work just as well. To be even more fair, Reflection is slow, so an optimization may be in order, but honestly that's something the DI engine should've been helping with. Speed and simplicity are each grand contributors to TCO.

All in all, there's no need for an explicit factory, because "finding a named service" is such a reusable concept, and factory classes don't scale as a solution. And a Func<> seems fine, but a switch block is so bleh, and again, you'll be writing Funcs as often as you'd be writing Factories. Start simple, reusable, with less code, and if that turns out not to do it for ya, then go complex.

Is it possible to program Android to act as physical USB keyboard?

I am bit late to comment in this question but it might be useful for some other people.

You can make your android phone to work like keyboard, mouse, camera, sound streaming system, tethering device. In short what ever usb gadget you see in the market and until and unless hardware doesn't limit you. Such as speed, or gadget interface not available.

USB device is of two type, host and gadget. So gadget device acts like client and usually has usb otg interface in most of the phones. So in gadget end, you can make your phone to behave like different device at all by switching between different configuration(you are already doing it when you go into usb settings and make your device as mass storage or anything else).

But for doing all these you have to modify android kernel. If you are a android device developer you can for sure do it.

what innerHTML is doing in javascript?

For understanding innerHTML property you first need to go through the basics of the javascript object and HTML DOM(Document object model). I will try to explain:

  1. JavaScript objects consist of properties and methods.
  2. for rendering HTML document web browser creates a DOM, in DOM every HTML element is treated as a JavaScript Object which has a set of properties and methods associated with it.

Now coming to your Question:

HTML code:

<p id= "myPara"> We love to Code.</p>

JavaScript code:

alert(document.getElementById("myPara").innerHTML);

here, document.getElementById("myPara") will return our html element as a javascript object which has pre-defined property innerHTML. innerHTML property contains the content of HTML tag.

Hope this will help.

You can run following HTML code in your browser to understand it:

<html>
<body>
  <p id= "myPara"> We love to Code.</p>
  <script>
    alert(document.getElementById("myPara").innerHTML);
  </script>
</body>
</html>

Python constructors and __init__

There is no function overloading in Python, meaning that you can't have multiple functions with the same name but different arguments.

In your code example, you're not overloading __init__(). What happens is that the second definition rebinds the name __init__ to the new method, rendering the first method inaccessible.

As to your general question about constructors, Wikipedia is a good starting point. For Python-specific stuff, I highly recommend the Python docs.

Conversion from Long to Double in Java

As already mentioned, you can simply cast long to double. But be careful with long to double conversion because long to double is a narrowing conversion in java.

Conversion from type double to type long requires a nontrivial translation from a 64-bit floating-point value to the 64-bit integer representation. Depending on the actual run-time value, information may be lost.

e.g. following program will print 1 not 0

    long number = 499999999000000001L;
    double converted = (double) number;
    System.out.println( number - (long) converted);

Opening A Specific File With A Batch File?

start wgnplot.exe "c:\path to file to open\foo.dat"

SyntaxError: JSON.parse: unexpected character at line 1 column 1 of the JSON data

Changing the data type to text helped dataType: 'text'

I have check with JSONlint and my json format was proper. Still it was throwing error when I set dataType: 'json'

JSON Data: {"eventinvite":1,"groupcount":8,"totalMessagesUnread":0,"unreadmessages":{"378":0,"379":0,"380":0,"385":0,"390":0,"393":0,"413":0,"418":0}} 

Eclipse: Error ".. overlaps the location of another project.." when trying to create new project

Go to the actual FILE menu and create a new general project.

If the project type isn't recognized, preventing one of these import methods from working, then try this. Once you add the generic project, you can then add support for whatever language you require.

wget can't download - 404 error

I had the same problem. Solved using single quotes like this:

$ wget 'http://www.icerts.com/images/logo.jpg'

wget version in use:

$ wget --version
GNU Wget 1.11.4 Red Hat modified

How to drop all stored procedures at once in SQL Server database?

I would prefer to do it this way:

  • first generate the list of stored procedures to drop by inspecting the system catalog view:

    SELECT 'DROP PROCEDURE [' + SCHEMA_NAME(p.schema_id) + '].[' + p.NAME + '];'
    FROM sys.procedures p 
    

    This generates a list of DROP PROCEDURE statements in your SSMS output window.

  • copy that list into a new query window, and possibly adapt it / change it and then execute it

No messy and slow cursors, gives you the ability to check and double-check your list of procedure to be dropped before you actually drop it

iOS / Android cross platform development

MonoTouch and MonoDroid but what will happen to that part of Attachmate now is anybody's guess. Of course even with the mono solutions you're still creating non cross platform views but the idea being the reuse of business logic.

Keep an eye on http://www.xamarin.com/ it will be interesting to see what they come up with.

Where does Anaconda Python install on Windows?

You can search for "Anaconda prompt" in installed programs and run it.
When it opens, it shows the directory anaconda is working from.
enter image description here

As you can see c:\programdata\anaconda2 is my installed directory.
*side note: programdata folder is hidden in windows so you'll have to enter its path in the folder explorer to access it.

Format output string, right alignment

To do it by using f-string and with control of the number of trailing digits:

print(f'A number -> {my_number:>20.5f}')

Maximum number of records in a MySQL database table

There is no limit. It only depends on your free memory and system maximum file size. But that doesn't mean you shouldn't take precautionary measure in tackling memory usage in your database. Always create a script that can delete rows that are out of use or that will keep total no of rows within a particular figure, say a thousand.

JQuery: detect change in input field

Use $.on() to bind your chosen event to the input, don't use the shortcuts like $.keydown() etc because as of jQuery 1.7 $.on() is the preferred method to attach event handlers (see here: http://api.jquery.com/on/ and http://api.jquery.com/bind/).

$.keydown() is just a shortcut to $.bind('keydown'), and $.bind() is what $.on() replaces (among others).

To answer your question, as far as I'm aware, unless you need to fire an event on keydown specifically, the change event should do the trick for you.

$('element').on('change', function(){
    console.log('change');
});

To respond to the below comment, the javascript change event is documented here: https://developer.mozilla.org/en-US/docs/Web/Events/change

And here is a working example of the change event working on an input element, using jQuery: http://jsfiddle.net/p1m4xh08/

Installing ADB on macOS

  1. You must download Android SDK from this link.

  2. You can really put it anywhere, but the best place at least for me was right in the YOUR USERNAME folder root.

  3. Then you need to set the path by copying the below text, but edit your username into the path, copy the text into Terminal by hitting command+spacebar type terminal. export PATH = ${PATH}:/Users/**YOURUSERNAME**/android-sdk/platform-tools/

  4. Verify ADB works by hitting command+spacebar and type terminal, and type ADB.

There you go. You have ADB setup on MAC OS X. It works on latest MAC OS X 10.10.3.

R Plotting confidence bands with ggplot

require(ggplot2)
require(nlme)

set.seed(101)
mp <-data.frame(year=1990:2010)
N <- nrow(mp)

mp <- within(mp,
         {
             wav <- rnorm(N)*cos(2*pi*year)+rnorm(N)*sin(2*pi*year)+5
             wow <- rnorm(N)*wav+rnorm(N)*wav^3
         })

m01 <- gls(wow~poly(wav,3), data=mp, correlation = corARMA(p=1))

Get fitted values (the same as m01$fitted)

fit <- predict(m01)

Normally we could use something like predict(...,se.fit=TRUE) to get the confidence intervals on the prediction, but gls doesn't provide this capability. We use a recipe similar to the one shown at http://glmm.wikidot.com/faq :

V <- vcov(m01)
X <- model.matrix(~poly(wav,3),data=mp)
se.fit <- sqrt(diag(X %*% V %*% t(X)))

Put together a "prediction frame":

predframe <- with(mp,data.frame(year,wav,
                                wow=fit,lwr=fit-1.96*se.fit,upr=fit+1.96*se.fit))

Now plot with geom_ribbon

(p1 <- ggplot(mp, aes(year, wow))+
    geom_point()+
    geom_line(data=predframe)+
    geom_ribbon(data=predframe,aes(ymin=lwr,ymax=upr),alpha=0.3))

year vs wow

It's easier to see that we got the right answer if we plot against wav rather than year:

(p2 <- ggplot(mp, aes(wav, wow))+
    geom_point()+
    geom_line(data=predframe)+
    geom_ribbon(data=predframe,aes(ymin=lwr,ymax=upr),alpha=0.3))

wav vs wow

It would be nice to do the predictions with more resolution, but it's a little tricky to do this with the results of poly() fits -- see ?makepredictcall.

Is there a way to disable initial sorting for jquery DataTables?

Try this:

$(document).ready( function () {
  $('#example').dataTable({
    "order": []
  });
});

this will solve your problem.

Why do I need to configure the SQL dialect of a data source?

The SQL dialect converts the HQL query which we write in our java or any other object oriented program to the specific database SQL.

For example in the java suppose I write List employees = session.createQuery("FROM Employee").list();

but when my dialect is <property name="hibernate.dialect"> org.hibernate.dialect.MySQLDialect

The HQL ("FROM Employee") gets converted to "SELECT * FROM EMPLOYEE" before hitting the MySQL database

How to debug Spring Boot application with Eclipse?

Please see http://java.dzone.com/articles/how-debug-remote-java-applicat to enable the remote debugging. If you are using tomcat to run your application, start tomcat with remote debug parameters or you can start tomcat with JPDA support by using following command.

Windows

<tomcat bin dir>/startup.bat jpda

*nix

<tomcat bin dir>/startup.sh jpda

this will enable remote debugging on port 8000

Get a list of checked checkboxes in a div using jQuery

Combination of two previous answers:

var selected = [];
$('#checkboxes input:checked').each(function() {
    selected.push($(this).attr('name'));
});

jQuery AJAX single file upload

After hours of searching and looking for answer, finally I made it!!!!! Code is below :))))

HTML:

<form id="fileinfo" enctype="multipart/form-data" method="post" name="fileinfo">
    <label>File to stash:</label>
    <input type="file" name="file" required />
</form>
<input type="button" value="Stash the file!"></input>
<div id="output"></div>

jQuery:

$(function(){
    $('#uploadBTN').on('click', function(){ 
        var fd = new FormData($("#fileinfo"));
        //fd.append("CustomField", "This is some extra data");
        $.ajax({
            url: 'upload.php',  
            type: 'POST',
            data: fd,
            success:function(data){
                $('#output').html(data);
            },
            cache: false,
            contentType: false,
            processData: false
        });
    });
});

In the upload.php file you can access the data passed with $_FILES['file'].

Thanks everyone for trying to help:)

I took the answer from here (with some changes) MDN

Remove the title bar in Windows Forms

Set FormsBorderStyle of the Form to None.

If you do, it's up to you how to implement the dragging and closing functionality of the window.

Event when window.location.href changes

I use this script in my extension "Grab Any Media" and work fine ( like youtube case )

var oldHref = document.location.href;

window.onload = function() {

    var
         bodyList = document.querySelector("body")

        ,observer = new MutationObserver(function(mutations) {

            mutations.forEach(function(mutation) {

                if (oldHref != document.location.href) {

                    oldHref = document.location.href;

                    /* Changed ! your code here */

                }

            });

        });

    var config = {
        childList: true,
        subtree: true
    };

    observer.observe(bodyList, config);

};

Reduce git repository size

This should not affect everyone, but one of the semi-hidden reasons of the repository size being large could be Git submodules.

You might have added one or more submodules, but stopped using it at some time, and some files remained in .git/modules directory. To make redundant submodule files gone away, see this question.

However, just like the main repository, the other way is to navigate to the submodule directory in .git/modules, and do a, for example, git gc --aggressive --prune.

These should have a good impact in the repository size, but as long as you use Git submodules, e.g. especially with large libraries, your repository size should not change drastically.

Get folder up one level

You could do either:

dirname(__DIR__);

Or:

__DIR__ . '/..';

...but in a web server environment you will probably find that you are already working from current file's working directory, so you can probably just use:

'../'

...to reference the directory above. You can replace __DIR__ with dirname(__FILE__) before PHP 5.3.0.

You should also be aware what __DIR__ and __FILE__ refers to:

The full path and filename of the file. If used inside an include, the name of the included file is returned.

So it may not always point to where you want it to.

PHP & localStorage;

localStorage is something that is kept on the client side. There is no data transmitted to the server side.

You can only get the data with JavaScript and you can send it to the server side with Ajax.

Copying from one text file to another using Python

Safe and memory-saving:

with open("out1.txt", "w") as fw, open("in.txt","r") as fr: 
    fw.writelines(l for l in fr if "tests/file/myword" in l)

It doesn't create temporary lists (what readline and [] would do, which is a non-starter if the file is huge), all is done with generator comprehensions, and using with blocks ensure that the files are closed on exit.

Django - Static file not found

TEMPLATE_DIR=os.path.join(BASE_DIR,'templates')
STATIC_DIR=os.path.join(BASE_DIR,'static')

STATICFILES_DIRS=[STATIC_DIR]

How to remove components created with Angular-CLI

No As of now you can't do this by any command. You've to remove Manually from app.module.ts and app.routing.module.ts if you're using Angular 5

Removing unwanted table cell borders with CSS

Try assigning the style of border: 0px; border-collapse: collapse; to the table element.

Is there StartsWith or Contains in t sql with variables?

It seems like what you want is http://msdn.microsoft.com/en-us/library/ms186323.aspx.

In your example it would be (starts with):

set @isExpress = (CharIndex('Express Edition', @edition) = 1)

Or contains

set @isExpress = (CharIndex('Express Edition', @edition) >= 1)

How to uninstall Golang?

In MacOS, you can just do it with brew:

brew uninstall go
brew install go
brew upgrade go

Using getopts to process long and short command line options

In ksh93, getopts does support long names...

while getopts "f(file):s(server):" flag
do
    echo "$flag" $OPTIND $OPTARG
done

Or so the tutorials I have found have said. Try it and see.

Round to at most 2 decimal places (only if necessary)

There is a solution working for all numbers, give it a try. expression is given below.

Math.round((num + 0.00001) * 100) / 100. Try Math.round((1.005 + 0.00001) * 100) / 100 and Math.round((1.0049 + 0.00001) * 100) / 100

I recently tested every possible solution and finally arrived at the output after trying almost 10 times. Here is a screenshot of issue arised during caculations, Screen Capture.

head over to the amount field, It's returning almost infinite. I gave a try to toFixed() method but it's not working for some cases(i.e try with PI) and finally derived s solution given above.

Raising a number to a power in Java

1) We usually do not use int data types to height, weight, distance, temperature etc.(variables which can have decimal points) Therefore height, weight should be double or float. but double is more accurate than float when you have more decimal points

2) And instead of ^, you can change that calculation as below using Math.pow()

bmi = (weight/(Math.pow(height/100, 2)));

3) Math.pow() method has below definition

Math.pow(double var_1, double var_2);

Example:

i) Math.pow(8, 2) is produced 64 (8 to the power 2)

ii) Math.pow(8.2, 2.1) is produced 82.986813689753 (8.2 to the power 2.1)

T-SQL: Export to new Excel file

Use PowerShell:

$Server = "TestServer"
$Database = "TestDatabase"
$Query = "select * from TestTable"
$FilePath = "C:\OutputFile.csv"

# This will overwrite the file if it already exists.
Invoke-Sqlcmd -Query $Query -Database $Database -ServerInstance $Server | Export-Csv $FilePath

In my usual cases, all I really need is a CSV file that can be read by Excel. However, if you need an actual Excel file, then tack on some code to convert the CSV file to an Excel file. This answer gives a solution for this, but I've not tested it.

How to check if a query string value is present via JavaScript?

this function help you to get parameter from URL in JS

function getQuery(q) {
    return (window.location.search.match(new RegExp('[?&]' + q + '=([^&]+)')) || [, null])[1];
}

PHP: Read Specific Line From File

I like daggett answer but there is another solution you can get try if your file is not big enough.

$file = __FILE__; // Let's take the current file just as an example.

$start_line = __LINE__ -1; // The same with the line what we look for. Take the line number where $line variable is declared as the start.

$lines_to_display = 5; // The number of lines to display. Displays only the $start_line if set to 1. If $lines_to_display argument is omitted displays all lines starting from the $start_line.

echo implode('', array_slice(file($file), $start_line, lines_to_display));

How do I deal with installing peer dependencies in Angular CLI?

Peer dependency warnings, more often than not, can be ignored. The only time you will want to take action is if the peer dependency is missing entirely, or if the version of a peer dependency is higher than the version you have installed.

Let's take this warning as an example:

npm WARN @angular/[email protected] requires a peer of @angular/[email protected] but none is installed. You must install peer dependencies yourself.

With Angular, you would like the versions you are using to be consistent across all packages. If there are any incompatible versions, change the versions in your package.json, and run npm install so they are all synced up. I tend to keep my versions for Angular at the latest version, but you will need to make sure your versions are consistent for whatever version of Angular you require (which may not be the most recent).

In a situation like this:

npm WARN [email protected] requires a peer of @angular/core@^2.4.0 || ^4.0.0 but none is installed. You must install peer dependencies yourself.

If you are working with a version of Angular that is higher than 4.0.0, then you will likely have no issues. Nothing to do about this one then. If you are using an Angular version under 2.4.0, then you need to bring your version up. Update the package.json, and run npm install, or run npm install for the specific version you need. Like this:

npm install @angular/[email protected] --save

You can leave out the --save if you are running npm 5.0.0 or higher, that version saves the package in the dependencies section of the package.json automatically.

In this situation:

npm WARN optional SKIPPING OPTIONAL DEPENDENCY: [email protected] (node_modules\fsevents): npm WARN notsup SKIPPING OPTIONAL DEPENDENCY: Unsupported platform for [email protected]: wanted {"os":"darwin","arch":"any"} (current: {"os":"win32","arch":"x64"})

You are running Windows, and fsevent requires OSX. This warning can be ignored.

Hope this helps, and have fun learning Angular!

Access restriction: Is not accessible due to restriction on required library ..\jre\lib\rt.jar

Not a true solution, but everywhere I looked the solution suggested was to simply tell Eclipse that those aren't errors. You can change it by going to Properties --> Java Compiler --> Errors Warnings --> Deprecated and restrited APIs --> Forbidden reference (acess rule), Change it from Error to Warning or Ignore.

Set an environment variable in git bash

A normal variable is set by simply assigning it a value; note that no whitespace is allowed around the =:

HOME=c

An environment variable is a regular variable that has been marked for export to the environment.

export HOME
HOME=c

You can combine the assignment with the export statement.

export HOME=c

Bulk Insert Correctly Quoted CSV File in SQL Server

I've spent half a day on this problem. It's best to import using SQL Server Import & Export data wizard. There is a setting in that wizard which solves this problem. Detailed screenshots here: https://www.mssqltips.com/sqlservertip/1316/strip-double-quotes-from-an-import-file-in-integration-services-ssis/ Thanks

How can I solve the error 'TS2532: Object is possibly 'undefined'?

For others facing a similar problem to mine, where you know a particular object property cannot be null, you can use the non-null assertion operator (!) after the item in question. This was my code:

  const naciStatus = dataToSend.naci?.statusNACI;
  if (typeof naciStatus != "undefined") {
    switch (naciStatus) {
      case "AP":
        dataToSend.naci.certificateStatus = "FALSE";
        break;
      case "AS":
      case "WR":
        dataToSend.naci.certificateStatus = "TRUE";
        break;
      default:
        dataToSend.naci.certificateStatus = "";
    }
  }

And because dataToSend.naci cannot be undefined in the switch statement, the code can be updated to include exclamation marks as follows:

  const naciStatus = dataToSend.naci?.statusNACI;
  if (typeof naciStatus != "undefined") {
    switch (naciStatus) {
      case "AP":
        dataToSend.naci!.certificateStatus = "FALSE";
        break;
      case "AS":
      case "WR":
        dataToSend.naci!.certificateStatus = "TRUE";
        break;
      default:
        dataToSend.naci!.certificateStatus = "";
    }
  }

How can labels/legends be added for all chart types in chart.js (chartjs.org)?

You can include a legend template in the chart options:

//legendTemplate takes a template as a string, you can populate the template with values from your dataset 
var options = {
  legendTemplate : '<ul>'
                  +'<% for (var i=0; i<datasets.length; i++) { %>'
                    +'<li>'
                    +'<span style=\"background-color:<%=datasets[i].lineColor%>\"></span>'
                    +'<% if (datasets[i].label) { %><%= datasets[i].label %><% } %>'
                  +'</li>'
                +'<% } %>'
              +'</ul>'
  }

  //don't forget to pass options in when creating new Chart
  var lineChart = new Chart(element).Line(data, options);

  //then you just need to generate the legend
  var legend = lineChart.generateLegend();

  //and append it to your page somewhere
  $('#chart').append(legend);

You'll also need to add some basic css to get it looking ok.

Convert RGBA PNG to RGB with PIL

Here's a solution in pure PIL.

def blend_value(under, over, a):
    return (over*a + under*(255-a)) / 255

def blend_rgba(under, over):
    return tuple([blend_value(under[i], over[i], over[3]) for i in (0,1,2)] + [255])

white = (255, 255, 255, 255)

im = Image.open(object.logo.path)
p = im.load()
for y in range(im.size[1]):
    for x in range(im.size[0]):
        p[x,y] = blend_rgba(white, p[x,y])
im.save('/tmp/output.png')

Adjusting the Xcode iPhone simulator scale and size

You are seeing it huge because of your screen resolution. iPhone 5's display is 640x1136. Current resolution of your display can be found in System preferences, and it's height on notebooks is usually around 1000 px (give or take). So surely, the simulator in 1:1 scale will take all the height of the screen and even more.

The iPhone simulator has three scales, 100%, 75% and 50%. You can change between them any time by pressing CMD+1, CMD+2, CMD+3 or from Window menu.

Note that 100%-mode is very helpful for graphic checks, on full resolution you will be able to notice all defects or measure point size of the elements.

List passed by ref - help me explain this behaviour

There are two parts of memory allocated for an object of reference type. One in stack and one in heap. The part in stack (aka a pointer) contains reference to the part in heap - where the actual values are stored.

When ref keyword is not use, just a copy of part in stack is created and passed to the method - reference to same part in heap. Therefore if you change something in heap part, those change will stayed. If you change the copied pointer - by assign it to refer to other place in heap - it will not affect to origin pointer outside of the method.

changing color of h2

Try CSS:

<h2 style="color:#069">Process Report</h2>

If you have more than one h2 tags which should have the same color add a style tag to the head tag like this:

<style type="text/css">
h2 {
    color:#069;
}
</style>

Angular - res.json() is not a function

HttpClient.get() applies res.json() automatically and returns Observable<HttpResponse<string>>. You no longer need to call this function yourself.

See Difference between HTTP and HTTPClient in angular 4?

Postgresql tables exists, but getting "relation does not exist" when querying

I hit this error and it turned out my connection string was pointing to another database, obviously the table didn't exist there.

I spent a few hours on this and no one else has mentioned to double check your connection string.

Git undo local branch delete

Follow these Steps:

1: Enter:

git reflog show 

This will display all the Commit history, you need to select the sha-1 that has the last commit that you want to get back

2: create a branch name with the Sha-1 ID you selected eg: 8c87714

git branch your-branch-name 8c87714

What is the difference between a framework and a library?

From Web developer perspective:

  1. Library can be easily replaceable by another library. But framework cannot.

    If you don't like jquery date picker library, you can replace with other date picker such as bootstrap date picker or pickadate.

    If you don't like AngularJS on which you built your product, you cannot just replace with any other frameworks. You have to rewrite your entire code base.

  2. Mostly library takes very less learning curve compared to Frameworks. Eg: underscore.js is a library, Ember.js is a framework.

C# 'or' operator?

The single " | " operator will evaluate both sides of the expression.

    if (ActionsLogWriter.Close | ErrorDumpWriter.Close == true)
{
    // Do stuff here
}

The double operator " || " will only evaluate the left side if the expression returns true.

    if (ActionsLogWriter.Close || ErrorDumpWriter.Close == true)
{
    // Do stuff here
}

C# has many similarities to C++ but their still are differences between the two languages ;)

Change package name for Android in React Native

you can simply use react-native-rename npm package.

Install using

npm install react-native-rename -g

Then from the root of your React Native project execute the following

react-native-rename "MyApp" -b com.mycompany.myapp

react-native-rename on npm

but notice that, this lib remove your MainActivity.java and MainApplication.java. before changing your package name, give a backup from this two file and, after changing package name just put it back to their place. this solution work for me

more info: react-native-rename

How do you manually execute SQL commands in Ruby On Rails using NuoDB

For me, I couldn't get this to return a hash.

results = ActiveRecord::Base.connection.execute(sql)

But using the exec_query method worked.

results = ActiveRecord::Base.connection.exec_query(sql)

How to block calls in android

You can do it by listening to phone call events . You do it by having a BroadcastReceiver to PHONE_STATE and to NEW_OUTGOING_CALL. You find there what is the phone number.

Then when you decide to end the call, this is a bit tricky, because only from Android P it's guaranteed to work. Check here.

How to get file path from OpenFileDialog and FolderBrowserDialog?

I am sorry if i am late to reply here but i just thought i should throw in a much simpler solution for the OpenDialog.

OpenDialog ofd = new OpenDialog();
var fullPathIncludingFileName = ofd.Filename; //returns the full path including the filename
var fullPathExcludingFileName = ofd.Filename.Replace(ofd.SafeFileName, "");//will remove the filename from the full path

I have not yet used a FolderBrowserDialog before so i will trust my fellow coders's take on this. I hope this helps.

How to round float numbers in javascript?

Number((6.688689).toFixed(1)); // 6.7

var number = 6.688689;
var roundedNumber = Math.round(number * 10) / 10;

Use toFixed() function.

(6.688689).toFixed(); // equal to "7"
(6.688689).toFixed(1); // equal to "6.7"
(6.688689).toFixed(2); // equal to "6.69"

Location of the mongodb database on mac

If mongodb is installed via Homebrew the default location is:

/usr/local/var/mongodb

See the answer from @simonbogarde for the location of other interesting files that are different when using Homebrew.

Flutter: Run method on Widget build complete

UPDATE: Flutter v1.8.4

Both mentioned codes are working now:

Working:

WidgetsBinding.instance
        .addPostFrameCallback((_) => yourFunction(context));

Working

import 'package:flutter/scheduler.dart';

SchedulerBinding.instance.addPostFrameCallback((_) => yourFunction(context));

How can I make my layout scroll both horizontally and vertically?

You can do this by using below code

<HorizontalScrollView
                    android:layout_width="match_parent"
                    android:layout_height="match_parent">
                    <ScrollView
                        android:layout_width="wrap_content"
                        android:layout_height="match_parent">
                        <LinearLayout
                            android:layout_width="match_parent"
                            android:layout_height="wrap_content">
                            
                        </LinearLayout>
                    </ScrollView>
    </HorizontalScrollView>

Forbidden You don't have permission to access / on this server

This works for me on Mac OS Mojave:

<Directory "/Users/{USERNAME}/Sites/project">
    Options +Indexes +FollowSymLinks +MultiViews
    AllowOverride All
    require all granted
</Directory>

How to filter empty or NULL names in a QuerySet?

You could do this:

Name.objects.exclude(alias__isnull=True)

If you need to exclude null values and empty strings, the preferred way to do so is to chain together the conditions like so:

Name.objects.exclude(alias__isnull=True).exclude(alias__exact='')

Chaining these methods together basically checks each condition independently: in the above example, we exclude rows where alias is either null or an empty string, so you get all Name objects that have a not-null, not-empty alias field. The generated SQL would look something like:

SELECT * FROM Name WHERE alias IS NOT NULL AND alias != ""

You can also pass multiple arguments to a single call to exclude, which would ensure that only objects that meet every condition get excluded:

Name.objects.exclude(some_field=True, other_field=True)

Here, rows in which some_field and other_field are true get excluded, so we get all rows where both fields are not true. The generated SQL code would look a little like this:

SELECT * FROM Name WHERE NOT (some_field = TRUE AND other_field = TRUE)

Alternatively, if your logic is more complex than that, you could use Django's Q objects:

from django.db.models import Q
Name.objects.exclude(Q(alias__isnull=True) | Q(alias__exact=''))

For more info see this page and this page in the Django docs.

As an aside: My SQL examples are just an analogy--the actual generated SQL code will probably look different. You'll get a deeper understanding of how Django queries work by actually looking at the SQL they generate.

Make body have 100% of the browser height

Here:

html,body{
    height:100%;
}

body{
  margin:0;
  padding:0
  background:blue;
}

What is an NP-complete in computer science?

NP stands for Non-deterministic Polynomial time.

This means that the problem can be solved in Polynomial time using a Non-deterministic Turing machine (like a regular Turing machine but also including a non-deterministic "choice" function). Basically, a solution has to be testable in poly time. If that's the case, and a known NP problem can be solved using the given problem with modified input (an NP problem can be reduced to the given problem) then the problem is NP complete.

The main thing to take away from an NP-complete problem is that it cannot be solved in polynomial time in any known way. NP-Hard/NP-Complete is a way of showing that certain classes of problems are not solvable in realistic time.

Edit: As others have noted, there are often approximate solutions for NP-Complete problems. In this case, the approximate solution usually gives an approximation bound using special notation which tells us how close the approximation is.

How to add a Browse To File dialog to a VB.NET application

You're looking for the OpenFileDialog class.

For example:

Sub SomeButton_Click(sender As Object, e As EventArgs) Handles SomeButton.Click
    Using dialog As New OpenFileDialog
        If dialog.ShowDialog() <> DialogResult.OK Then Return
        File.Copy(dialog.FileName, newPath)
    End Using
End Sub

C++ Matrix Class

For a matrix class, you want to stay away from overloading the [] operator.
See C++ FAQ 13.10

Also, search the web for some freeware Matrix classes. Worst case, they can give you guidance. Best case, less software that you have to write and debug.

Tomcat startup logs - SEVERE: Error filterStart how to get a stack trace?

Just wanted to contribute after spending the last hour on a nearly identical problem. My solution was that somehow our applicatons .jar was corrupted, so placing the jar from our dev server provided a fix.

Subtract one day from datetime

To simply subtract one day from todays date:

Select DATEADD(day,-1,GETDATE())

(original post used -7 and was incorrect)

Android: disabling highlight on listView click

in code

listView.setSelector(getResources().getDrawable(R.drawable.transparent));

and add small transparent image to drawable folder.

Like: transparent.xml

<?xml version="1.0" encoding="utf-8"?>    
<shape xmlns:android="http://schemas.android.com/apk/res/android">
    <solid android:color="#00000000"/>
</shape>

How to check empty object in angular 2 template using *ngIf

A bit of a lengthier way (if interested in it):

In your typescript code do this:

this.objectLength = Object.keys(this.previous_info).length != 0;

And in the template:

ngIf="objectLength != 0"

How to create User/Database in script for Docker Postgres

I add custom commands to a environment evoked in a CMD after starting services... I haven't done it with postgres, but with Oracle:

#set up var with noop command
RUN export POST_START_CMDS=":"
RUN mkdir /scripts
ADD script.sql /scripts
CMD service oracle-xe start; $POST_START_CMDS; tail -f /var/log/dmesg

and start with

docker run -d ... -e POST_START_CMDS="su - oracle -c 'sqlplus @/scripts/script' " <image>

.

What is Persistence Context?

While @pritam kumar gives a good overview the 5th point is not true.

Persistence Context can be either Transaction Scoped-- the Persistence Context 'lives' for the length of the transaction, or Extended-- the Persistence Context spans multiple transactions.

https://blogs.oracle.com/carolmcdonald/entry/jpa_caching

JPA's EntityManager and Hibernate's Session offer an extended Persistence Context.

How to set the focus for a particular field in a Bootstrap modal, once it appears

I had the same problem with bootstrap 3, focus when i click the link, but not when trigger the event with javascript. The solution:

$('#myModal').on('shown.bs.modal', function () {
    setTimeout(function(){
        $('#inputId').focus();
    }, 100);
});

Probably it´s something about the animation!

How to make a boolean variable switch between true and false every time a method is invoked?

value ^= true;

That is value xor-equals true, which will flip it every time, and without any branching or temporary variables.

Set inputType for an EditText Programmatically?

Hide:

edtPassword.setInputType(InputType.TYPE_CLASS_TEXT);
edtPassword.setTransformationMethod(null);

Show:

edtPassword.setInputType(InputType.TYPE_TEXT_VARIATION_PASSWORD);                    
edtPassword.setTransformationMethod(PasswordTransformationMethod.getInstance());

Fragment onResume() & onPause() is not called on backstack

Follow the below steps, and you shall get the needed answer

1- For both fragments, create a new abstract parent one.
2- Add a custom abstract method that should be implemented by both of them.
3- Call it from the current instance before replacing with the second one.

How to display Woocommerce Category image?

To display the category image for the currently displayed category in archive-product.php, use the current category term_id when is_product_category() is true:

// verify that this is a product category page
if ( is_product_category() ){
    global $wp_query;

    // get the query object
    $cat = $wp_query->get_queried_object();

    // get the thumbnail id using the queried category term_id
    $thumbnail_id = get_term_meta( $cat->term_id, 'thumbnail_id', true ); 

    // get the image URL
    $image = wp_get_attachment_url( $thumbnail_id ); 

    // print the IMG HTML
    echo "<img src='{$image}' alt='' width='762' height='365' />";
}

Cassandra port usage - how are the ports used?

For Apache Cassandra 2.0 you need to take into account the following TCP ports: (See EC2 security group configuration and Apache Cassandra FAQ)

Cassandra

  • 7199 JMX monitoring port
  • 1024 - 65355 Random port required by JMX. Starting with Java 7u4 a specific port can be specified using the com.sun.management.jmxremote.rmi.port property.
  • 7000 Inter-node cluster
  • 7001 SSL inter-node cluster
  • 9042 CQL Native Transport Port
  • 9160 Thrift

DataStax OpsCenter

  • 61620 opscenterd daemon
  • 61621 Agent
  • 8888 Website

Architecture

A possible architecture with Cassandra + OpsCenter on EC2 could look like this: AWS EC2 with OpsCenter

How do I get an Excel range using row and column numbers in VSTO / C#?

UsedRange work fine with "virgins" cells, but if your cells are filled in the past, then UsedRange will deliver to you the old value.

For example:

"Think in a Excel sheet that have cells A1 to A5 filled with text". In this scenario, UsedRange must be implemented as:

Long SheetRows;
SheetRows = ActiveSheet.UsedRange.Rows.Count;

A watch to SheetRows variable must display a value of 5 after the execution of this couple of lines.

Q1: But, what happen if the value of A5 is deleted?

A1: The value of SheetRows would be 5

Q2: Why this?

A2: Because MSDN define UsedRange property as:

Gets a Microsoft.Office.Interop.Excel.Range object that represents all the cells that have contained a value at any time.


So, the question is: Exist some/any workaround for this behavior?

I think in 2 alternatives:

  1. Avoid deleting the content of the cell, preferring deletion of the whole row (right click in the row number, then "delete row".
  2. Use CurrentRegion instead of UsedRange property as follow:

Long SheetRows;
SheetRows = ActiveSheet.Range("A1").CurrentRegion.Rows.Count;

HTTP Status 504

You can't. The problem is not that your app is impatient and timing out; the problem is that an intermediate proxy is impatient and timing out. "The server, while acting as a gateway or proxy, did not receive a timely response from the upstream server specified by the URI." (http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.5.5) It most likely indicates that the origin server is having some sort of issue, so it's not responding quickly to the forwarded request.

Possible solutions, none of which are likely to make you happy:

  • Increase timeout value of the proxy (if it's under your control)
  • Make your request to a different server (if there's another server with the same data)
  • Make your request differently (if possible) such that you are requesting less data at a time
  • Try again once the server is not having issues

ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2)

Upgrading MySQL fixed it for me. On RHEL-based servers, just run:

sudo yum upgrade mysql-server

What is the difference between XML and XSD?

SIMPLE XML EXAMPLE:

<school>
  <firstname>John</firstname>
  <lastname>Smith</lastname>
</school>

XSD OF ABOVE XML(Explained):

<xs:element name="school">
  <xs:complexType>
    <xs:sequence>
      <xs:element name="firstname" type="xs:string"/>
      <xs:element name="lastname" type="xs:string"/>
    </xs:sequence>
  </xs:complexType>
</xs:element>

Here:

xs:element : Defines an element.

xs:sequence : Denotes child elements only appear in the order mentioned.

xs:complexType : Denotes it contains other elements.

xs:simpleType : Denotes they do not contain other elements.

type: string, decimal, integer, boolean, date, time,

  • In simple words, xsd is another way to represent and validate XML data with the specific type.
  • With the help of extra attributes, we can perform multiple operations.

  • Performing any task on xsd is simpler than xml.

Oracle Installer:[INS-13001] Environment does not meet minimum requirements

its awful oracle installer:

[INS-13001]

I got it as I used MY_PC as NETBIOS name instead of MYPC (Underscore is bad for it..)

Can be an historical reason.. but message is obscure.

Get values from an object in JavaScript

In ES2017 you can use Object.values():

Object.values(data)

At the time of writing support is limited (FireFox and Chrome).All major browsers except IE support this now.

In ES2015 you can use this:

Object.keys(data).map(k => data[k])

$location / switching between html5 and hashbang mode / link rewriting

The documentation is not very clear about AngularJS routing. It talks about Hashbang and HTML5 mode. In fact, AngularJS routing operates in three modes:

  • Hashbang Mode
  • HTML5 Mode
  • Hashbang in HTML5 Mode

For each mode there is a a respective LocationUrl class (LocationHashbangUrl, LocationUrl and LocationHashbangInHTML5Url).

In order to simulate URL rewriting you must actually set html5mode to true and decorate the $sniffer class as follows:

$provide.decorator('$sniffer', function($delegate) {
  $delegate.history = false;
  return $delegate;
});

I will now explain this in more detail:

Hashbang Mode

Configuration:

$routeProvider
  .when('/path', {
    templateUrl: 'path.html',
});
$locationProvider
  .html5Mode(false)
  .hashPrefix('!');

This is the case when you need to use URLs with hashes in your HTML files such as in

<a href="index.html#!/path">link</a>

In the Browser you must use the following Link: http://www.example.com/base/index.html#!/base/path

As you can see in pure Hashbang mode all links in the HTML files must begin with the base such as "index.html#!".

HTML5 Mode

Configuration:

$routeProvider
  .when('/path', {
    templateUrl: 'path.html',
  });
$locationProvider
  .html5Mode(true);

You should set the base in HTML-file

<html>
  <head>
    <base href="/">
  </head>
</html>

In this mode you can use links without the # in HTML files

<a href="/path">link</a>

Link in Browser:

http://www.example.com/base/path

Hashbang in HTML5 Mode

This mode is activated when we actually use HTML5 mode but in an incompatible browser. We can simulate this mode in a compatible browser by decorating the $sniffer service and setting history to false.

Configuration:

$provide.decorator('$sniffer', function($delegate) {
  $delegate.history = false;
  return $delegate;
});
$routeProvider
  .when('/path', {
    templateUrl: 'path.html',
  });
$locationProvider
  .html5Mode(true)
  .hashPrefix('!');

Set the base in HTML-file:

<html>
  <head>
    <base href="/">
  </head>
</html>

In this case the links can also be written without the hash in the HTML file

<a href="/path">link</a>

Link in Browser:

http://www.example.com/index.html#!/base/path

How do I upgrade to Python 3.6 with conda?

This is how I mange to get (as currently there is no direct support- in future it will be for sure) python 3.9 in anaconda and windows 10
Note: I needed extra packages so install them, install only what you need

conda create --name e39 python=3.9 --channel conda-forge

Beautiful way to remove GET-variables with PHP?

just use echo'd javascript to rid the URL of any variables with a self-submitting, blank form:

    <?
    if (isset($_GET['your_var'])){
    //blah blah blah code
    echo "<script type='text/javascript'>unsetter();</script>"; 
    ?> 

Then make this javascript function:

    function unsetter() {
    $('<form id = "unset" name = "unset" METHOD="GET"><input type="submit"></form>').appendTo('body');
    $( "#unset" ).submit();
    }

Rails: Check output of path helper from console

For Rails 5.2.4.1, I had to

app.extend app._routes.named_routes.path_helpers_module
app.whatever_path

How to open a txt file and read numbers in Java

   try{

    BufferedReader br = new BufferedReader(new FileReader("textfile.txt"));
    String strLine;
    //Read File Line By Line
    while ((strLine = br.readLine()) != null)   {
      // Print the content on the console
      System.out.println (strLine);
    }
    //Close the input stream
    in.close();
    }catch (Exception e){//Catch exception if any
      System.err.println("Error: " + e.getMessage());
    }finally{
     in.close();
    }

This will read line by line,

If your no. are saperated by newline char. then in place of

 System.out.println (strLine);

You can have

try{
int i = Integer.parseInt(strLine);
}catch(NumberFormatException npe){
//do something
}  

If it is separated by spaces then

try{
    String noInStringArr[] = strLine.split(" ");
//then you can parse it to Int as above
    }catch(NumberFormatException npe){
    //do something
    }  

Is arr.__len__() the preferred way to get the length of an array in Python?

The way you take a length of anything for which that makes sense (a list, dictionary, tuple, string, ...) is to call len on it.

l = [1,2,3,4]
s = 'abcde'
len(l) #returns 4
len(s) #returns 5

The reason for the "strange" syntax is that internally python translates len(object) into object.__len__(). This applies to any object. So, if you are defining some class and it makes sense for it to have a length, just define a __len__() method on it and then one can call len on those instances.

Is it a bad practice to use an if-statement without curly braces?

Use braces for all if statements even the simple ones. Or, rewrite a simple if statement to use the ternary operator:

if (someFlag) {
 someVar= 'someVal1';
} else {
 someVar= 'someVal2';
}

Looks much nicer like this:

someVar= someFlag ? 'someVal1' : 'someVal2';

But only use the ternary operator if you are absolutely sure there's nothing else that needs to go in the if/else blocks!

How do I compare 2 rows from the same table (SQL Server)?

SELECT COUNT(*) FROM (SELECT * FROM tbl WHERE id=1 UNION SELECT * FROM tbl WHERE id=2) a

If you got two rows, they different, if one - the same.

Detect IF hovering over element with jQuery

I like the first response, but for me it's weird. When attempting to check just after page load for the mouse, I have to put in at least a 500 millisecond delay for it to work:

$(window).on('load', function() {
    setTimeout(function() {
        $('img:hover').fadeOut().fadeIn();
    }, 500);
});

http://codepen.io/molokoloco/pen/Grvkx/

parsing JSONP $http.jsonp() response in angular.js

for me the above solutions worked only once i added "format=jsonp" to the request parameters.

Using Ajax.BeginForm with ASP.NET MVC 3 Razor

Ajax forms work asynchronously using Javascript. So it is required, to load the script files for execution. Even though it's a small performance compromise, the execution happens without postback.

We need to understand the difference between the behaviours of both Html and Ajax forms.

Ajax:

  1. Won't redirect the form, even you do a RedirectAction().

  2. Will perform save, update and any modification operations asynchronously.

Html:

  1. Will redirect the form.

  2. Will perform operations both Synchronously and Asynchronously (With some extra code and care).

Demonstrated the differences with a POC in below link. Link

How to set different colors in HTML in one statement?

Use the span tag

<style>
    .redText
    {
        color:red;
    }
    .blackText
    {
        color:black;
        font-weight:bold;
    }
</style>

<span class="redText">My Name is:</span>&nbsp;<span class="blackText">Tintincute</span>

It's also a good idea to avoid inline styling. Use a custom CSS class instead.

Set a default font for whole iOS app?

I created my own conversion of typography for Swift 4 after reviewing a few posts, it covers most of the cases, such as:

1st Add fonts to project estructure and to .plist file (with the same name):

<key>UIAppFonts</key>
<array>
    <string>Typo-Light.ttf</string>
    <string>Typo-Regular.ttf</string>
    <string>Typo-Semibold.ttf</string>
    <string>Typo-LightItalic.ttf</string>
</array>

Then

struct Resources {

    struct Fonts {
        //struct is extended in Fonts
    }
}

extension Resources.Fonts {

    enum Weight: String {
        case light = "Typo-Light"
        case regular = "Typo-Regular"
        case semibold = "Typo-Semibold"
        case italic = "Typo-LightItalic"
    }
}

extension UIFontDescriptor.AttributeName {
    static let nsctFontUIUsage = UIFontDescriptor.AttributeName(rawValue: "NSCTFontUIUsageAttribute")
}

extension UIFont {

    @objc class func mySystemFont(ofSize: CGFloat, weight: UIFont.Weight) -> UIFont {
        switch weight {
        case .semibold, .bold, .heavy, .black:
            return UIFont(name: Resources.Fonts.Weight.semibold.rawValue, size: ofSize)!

        case .medium, .regular:
            return UIFont(name: Resources.Fonts.Weight.regular.rawValue, size: ofSize)!

        default:
            return UIFont(name: Resources.Fonts.Weight.light.rawValue, size: ofSize)!
        }
    }

    @objc class func mySystemFont(ofSize size: CGFloat) -> UIFont {
        return UIFont(name: Resources.Fonts.Weight.light.rawValue, size: size)!
    }

    @objc class func myBoldSystemFont(ofSize size: CGFloat) -> UIFont {
        return UIFont(name: Resources.Fonts.Weight.semibold.rawValue, size: size)!
    }

    @objc class func myItalicSystemFont(ofSize size: CGFloat) -> UIFont {
        return UIFont(name: Resources.Fonts.Weight.italic.rawValue, size: size)!
    }

    @objc convenience init(myCoder aDecoder: NSCoder) {
        guard
            let fontDescriptor = aDecoder.decodeObject(forKey: "UIFontDescriptor") as? UIFontDescriptor,
            let fontAttribute = fontDescriptor.fontAttributes[.nsctFontUIUsage] as? String else {
                self.init(myCoder: aDecoder)
                return
        }
        var fontName = ""
        switch fontAttribute {
        case "CTFontRegularUsage", "CTFontMediumUsage":
            fontName = Resources.Fonts.Weight.regular.rawValue
        case "CTFontEmphasizedUsage", "CTFontBoldUsage", "CTFontSemiboldUsage","CTFontHeavyUsage", "CTFontBlackUsage":
            fontName = Resources.Fonts.Weight.semibold.rawValue
        case "CTFontObliqueUsage":
            fontName = Resources.Fonts.Weight.italic.rawValue
        default:
            fontName = Resources.Fonts.Weight.light.rawValue
        }
        self.init(name: fontName, size: fontDescriptor.pointSize)!
    }

    class func overrideDefaultTypography() {
        guard self == UIFont.self else { return }

        if let systemFontMethodWithWeight = class_getClassMethod(self, #selector(systemFont(ofSize: weight:))),
            let mySystemFontMethodWithWeight = class_getClassMethod(self, #selector(mySystemFont(ofSize: weight:))) {
            method_exchangeImplementations(systemFontMethodWithWeight, mySystemFontMethodWithWeight)
        }

        if let systemFontMethod = class_getClassMethod(self, #selector(systemFont(ofSize:))),
            let mySystemFontMethod = class_getClassMethod(self, #selector(mySystemFont(ofSize:))) {
            method_exchangeImplementations(systemFontMethod, mySystemFontMethod)
        }

        if let boldSystemFontMethod = class_getClassMethod(self, #selector(boldSystemFont(ofSize:))),
            let myBoldSystemFontMethod = class_getClassMethod(self, #selector(myBoldSystemFont(ofSize:))) {
            method_exchangeImplementations(boldSystemFontMethod, myBoldSystemFontMethod)
        }

        if let italicSystemFontMethod = class_getClassMethod(self, #selector(italicSystemFont(ofSize:))),
            let myItalicSystemFontMethod = class_getClassMethod(self, #selector(myItalicSystemFont(ofSize:))) {
            method_exchangeImplementations(italicSystemFontMethod, myItalicSystemFontMethod)
        }

        if let initCoderMethod = class_getInstanceMethod(self, #selector(UIFontDescriptor.init(coder:))),
            let myInitCoderMethod = class_getInstanceMethod(self, #selector(UIFont.init(myCoder:))) {
            method_exchangeImplementations(initCoderMethod, myInitCoderMethod)
        }
    }
}

Finally call to created method at Appdelegate like next:

class AppDelegate: UIResponder, UIApplicationDelegate {
    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey : Any]? = nil) -> Bool {

        UIFont.overrideDefaultTypography()
        return true
    }
}

How to write macro for Notepad++?

I'm not sure if this helps, but I needed to create a macro to hold a snippet, so I simply recorded myself inserting the items and set a shortcut to it. Granted, I'm not using version 5.9 so there might be some slight version differences. To access the macro recorder go to Macro > Start Recording. Then you will perform your action and then go to Macro > Stop Recording. I'd recommend playing it back to ensure it's correct and then save and set your shortcut key.

Hope the helps.

Fragment Inside Fragment

Fragments can be added inside other fragments but then you will need to remove it from parent Fragment each time when onDestroyView() method of parent fragment is called. And again add it in Parent Fragment's onCreateView() method.

Just do like this :

@Override
    public void onDestroyView()
    {
                FragmentManager mFragmentMgr= getFragmentManager();
        FragmentTransaction mTransaction = mFragmentMgr.beginTransaction();
                Fragment childFragment =mFragmentMgr.findFragmentByTag("qa_fragment")
        mTransaction.remove(childFragment);
        mTransaction.commit();
        super.onDestroyView();
    }

Import Libraries in Eclipse?

If you want to get this library into your library and use it, follow these steps:

  1. You can create a new folder within Eclipse by right-clicking on your project, and selecting New Folder. The library folder is traditionally called lib.

  2. Drag and drop your jar folder into the new lib folder, and when prompted select Copy Files.

  3. Selecting the Project tab at the top of the screen, and click Properties.

  4. Select Java Build Path followed by the Libraries tab.

  5. Click the Add JARs… button and select your JAR file from within the lib folder.

  6. Your JAR file will now appear in both the lib and Referenced Libraries folders. You can explore the JAR's resources by clicking Referenced Libraries.

Convert decimal to binary in python

For the sake of completion: if you want to convert fixed point representation to its binary equivalent you can perform the following operations:

  1. Get the integer and fractional part.

    from decimal import *
    a = Decimal(3.625)
    a_split = (int(a//1),a%1)
    
  2. Convert the fractional part in its binary representation. To achieve this multiply successively by 2.

    fr = a_split[1]
    str(int(fr*2)) + str(int(2*(fr*2)%1)) + ...
    

You can read the explanation here.

Convert date to datetime in Python

If you need something quick, datetime_object.date() gives you a date of a datetime object.

Need a row count after SELECT statement: what's the optimal SQL approach?

If you're concerned the number of rows that meet the condition may change in the few milliseconds since execution of the query and retrieval of results, you could/should execute the queries inside a transaction:

BEGIN TRAN bogus

SELECT COUNT( my_table.my_col ) AS row_count
FROM my_table
WHERE my_table.foo = 'bar'

SELECT my_table.my_col
FROM my_table
WHERE my_table.foo = 'bar'
ROLLBACK TRAN bogus

This would return the correct values, always.

Furthermore, if you're using SQL Server, you can use @@ROWCOUNT to get the number of rows affected by last statement, and redirect the output of real query to a temp table or table variable, so you can return everything altogether, and no need of a transaction:

DECLARE @dummy INT

SELECT my_table.my_col
INTO #temp_table
FROM my_table
WHERE my_table.foo = 'bar'

SET @dummy=@@ROWCOUNT
SELECT @dummy, * FROM #temp_table

Regex Named Groups in Java

For those running pre-java7, named groups are supported by joni (Java port of the Oniguruma regexp library). Documentation is sparse, but it has worked well for us.
Binaries are available via Maven (http://repository.codehaus.org/org/jruby/joni/joni/).

How do I get console input in javascript?

You can try something like process.argv, that is if you are using node.js to run the program.
console.log(process.argv) => Would print an array containing

[                                                                                                                                                                                          
  '/usr/bin/node',                                                                                                                                                                         
  '/home/user/path/filename.js',                                                                                                                                            
  'your_input'                                                                                                                                                                                   
]

You get the user provided input via array index, i.e., console.log(process.argv[3]) This should provide you with the input which you can store.


Example:

var somevariable = process.argv[3]; // input one
var somevariable2 = process.argv[4]; // input two

console.log(somevariable);
console.log(somevariable2);

If you are building a command-line program then the npm package yargs would be really helpful.

How can I use different certificates on specific connections?

Create an SSLSocket factory yourself, and set it on the HttpsURLConnection before connecting.

...
HttpsURLConnection conn = (HttpsURLConnection)url.openConnection();
conn.setSSLSocketFactory(sslFactory);
conn.setMethod("POST");
...

You'll want to create one SSLSocketFactory and keep it around. Here's a sketch of how to initialize it:

/* Load the keyStore that includes self-signed cert as a "trusted" entry. */
KeyStore keyStore = ... 
TrustManagerFactory tmf = 
  TrustManagerFactory.getInstance(TrustManagerFactory.getDefaultAlgorithm());
tmf.init(keyStore);
SSLContext ctx = SSLContext.getInstance("TLS");
ctx.init(null, tmf.getTrustManagers(), null);
sslFactory = ctx.getSocketFactory();

If you need help creating the key store, please comment.


Here's an example of loading the key store:

KeyStore keyStore = KeyStore.getInstance(KeyStore.getDefaultType());
keyStore.load(trustStore, trustStorePassword);
trustStore.close();

To create the key store with a PEM format certificate, you can write your own code using CertificateFactory, or just import it with keytool from the JDK (keytool won't work for a "key entry", but is just fine for a "trusted entry").

keytool -import -file selfsigned.pem -alias server -keystore server.jks

How can I count the number of matches for a regex?

matcher.find() does not find all matches, only the next match.

Solution for Java 9+

long matches = matcher.results().count();

Solution for Java 8 and older

You'll have to do the following. (Starting from Java 9, there is a nicer solution)

int count = 0;
while (matcher.find())
    count++;

Btw, matcher.groupCount() is something completely different.

Complete example:

import java.util.regex.*;

class Test {
    public static void main(String[] args) {
        String hello = "HelloxxxHelloxxxHello";
        Pattern pattern = Pattern.compile("Hello");
        Matcher matcher = pattern.matcher(hello);

        int count = 0;
        while (matcher.find())
            count++;

        System.out.println(count);    // prints 3
    }
}

Handling overlapping matches

When counting matches of aa in aaaa the above snippet will give you 2.

aaaa
aa
  aa

To get 3 matches, i.e. this behavior:

aaaa
aa
 aa
  aa

You have to search for a match at index <start of last match> + 1 as follows:

String hello = "aaaa";
Pattern pattern = Pattern.compile("aa");
Matcher matcher = pattern.matcher(hello);

int count = 0;
int i = 0;
while (matcher.find(i)) {
    count++;
    i = matcher.start() + 1;
}

System.out.println(count);    // prints 3

Html.BeginForm and adding properties

I know this is old but you could create a custom extension if you needed to create that form over and over:

public static MvcForm BeginMultipartForm(this HtmlHelper htmlHelper)
{
    return htmlHelper.BeginForm(null, null, FormMethod.Post, 
     new Dictionary<string, object>() { { "enctype", "multipart/form-data" } });
}

Usage then just becomes

<% using(Html.BeginMultipartForm()) { %>

How to send an email from JavaScript

window.open('mailto:[email protected]'); as above does nothing to hide the "[email protected]" email address from being harvested by spambots. I used to constantly run into this problem.

var recipient="test";
var at = String.fromCharCode(64);
var dotcom="example.com";
var mail="mailto:";
window.open(mail+recipient+at+dotcom);

Set width of dropdown element in HTML select dropdown options

u can simply use "width" attribute of "style" to change the length of the dropdown box

<select class="my_dropdown" id="my_dropdown" style="width:APPROPRIATE WIDTH IN PIXLES">
<option value="1">LONG OPTION</option>
<option value="2">short</option>
</select>

e.g.

style="width:200px"

Easiest way to mask characters in HTML(5) text input

Use this JavaScript.

$(":input").inputmask();
$("#phone").inputmask({"mask": "(999) 999-9999"});

How do I break out of a loop in Perl?

Additional data (in case you have more questions):

FOO: {
       for my $i ( @listone ){
          for my $j ( @listtwo ){
                 if ( cond( $i,$j ) ){

                    last FOO;  # --->
                                   # |
                 }                 # |
          }                        # |
       }                           # |
 } # <-------------------------------

Find out how much memory is being used by an object in Python

Try this:

sys.getsizeof(object)

getsizeof() Return the size of an object in bytes. It calls the object’s __sizeof__ method and adds an additional garbage collector overhead if the object is managed by the garbage collector.

A recursive recipe

Tab key == 4 spaces and auto-indent after curly braces in Vim

Related, if you open a file that uses both tabs and spaces, assuming you've got

set expandtab ts=4 sw=4 ai

You can replace all the tabs with spaces in the entire file with

:%retab

How to print last two columns using awk

try with this

$ cat /tmp/topfs.txt
/dev/sda2      xfs        32G   10G   22G  32% /

awk print last column
$ cat /tmp/topfs.txt | awk '{print $NF}'

awk print before last column
$ cat /tmp/topfs.txt | awk '{print $(NF-1)}'
32%

awk - print last two columns
$ cat /tmp/topfs.txt | awk '{print $(NF-1), $NF}'
32% /

Convert string to Boolean in javascript

I believe the following code will do the work.

function isBoolean(foo) {
    if((foo + "") == 'true' || (foo + "") == 'false') {
        foo = (foo + "") == 'true';
    } else { 
        console.log("The variable does not have a boolean value.");
        return;
    }
    return foo;
}

Explaining the code:

foo + ""

converts the variable 'foo' to a string so if it is already boolean the function will not return an invalid result.

(foo + "") == 'true'

This comparison will return true only if 'foo' is equal to 'true' or true (string or boolean). Note that it is case-sensitive so 'True' or any other variation will result in false.

(foo + "") == 'true' || (foo + "") == 'false'

Similarly, the sentence above will result in true only if the variable 'foo' is equal to 'true', true, 'false' or false. So any other value like 'test' will return false and then it will not run the code inside the 'if' statement. This makes sure that only boolean values (string or not) will be considered.

In the 3rd line, the value of 'foo' is finally "converted" to boolean.

C# HttpWebRequest The underlying connection was closed: An unexpected error occurred on a send

Your project supports .Net Framework 4.0 and .Net Framework 4.5. If you have upgrade issues

ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12;

instead of can use;

ServicePointManager.SecurityProtocol = (SecurityProtocolType)3072;

MySQL: Error Code: 1118 Row size too large (> 8126). Changing some columns to TEXT or BLOB

I tried all the solutions here, but only this parameter

innodb_strict_mode             = 0

solved my day...

From the manual:

The innodb_strict_mode setting affects the handling of syntax errors for CREATE TABLE, ALTER TABLE and CREATE INDEX statements. innodb_strict_mode also enables a record size check, so that an INSERT or UPDATE never fails due to the record being too large for the selected page size.

Use nginx to serve static files from subdirectories of a given directory

It should work, however http://nginx.org/en/docs/http/ngx_http_core_module.html#alias says:

When location matches the last part of the directive’s value: it is better to use the root directive instead:

which would yield:

server {
  listen        8080;
  server_name   www.mysite.com mysite.com;
  error_log     /home/www-data/logs/nginx_www.error.log;
  error_page    404    /404.html;

  location /public/doc/ {
    autoindex on;
    root  /home/www-data/mysite;
  } 

  location = /404.html {
    root /home/www-data/mysite/static/html;
  }       
}

How to merge many PDF files into a single one?

First, get Pdftk:

sudo apt-get install pdftk

Now, as shown on example page, use

pdftk 1.pdf 2.pdf 3.pdf cat output 123.pdf

for merging pdf files into one.

Why is my JavaScript function sometimes "not defined"?

It shouldn't be possible for this to happen if you're just including the scripts on the page.

The "copyArray" function should always be available when the JavaScript code starts executing no matter if it is declared before or after it -- unless you're loading the JavaScript files in dynamically with a dependency library. There are all sorts of problems with timing if that's the case.

How can I restart a Java application?

Windows

public void restartApp(){

    // This launches a new instance of application dirctly, 
    // remember to add some sleep to the start of the cmd file to make sure current instance is
    // completely terminated, otherwise 2 instances of the application can overlap causing strange
    // things:)

    new ProcessBuilder("cmd","/c start /min c:/path/to/script/that/launches/my/application.cmd ^& exit").start();
    System.exit(0);
}

/min to start script in minimized window

^& exit to close cmd window after finish

a sample cmd script could be

@echo off
rem add some sleep (e.g. 10 seconds) to allow the preceding application instance to release any open resources (like ports) and exit gracefully, otherwise the new instance could fail to start
sleep 10   
set path=C:\someFolder\application_lib\libs;%path%
java -jar application.jar

sleep 10 sleep for 10 seconds

HttpListener Access Denied

I also faced similar problem.If you have already reserved url then you have to first delete the url to run in non admin mode else it will fail with Access is Denied error.

netsh http delete urlacl url=http://+:80

UNION with WHERE clause

Just a caution

If you tried

SELECT colA, colB FROM tableA WHERE colA > 1
UNION
SELECT colX, colA FROM tableB WHERE colA > 1

compared to:

SELECT * 
  FROM (SELECT colA, colB FROM tableA
        UNION
        SELECT colX, colA FROM tableB) 
 WHERE colA > 1

Then in the second query, the colA in the where clause will actually have the colX from tableB, making it a very different query. If columns are being aliased in this way, it can get confusing.

Compiler error "archive for required library could not be read" - Spring Tool Suite

Delete your C:\Users\PC\.m2** folder
and update maven project 

Programmatically Install Certificate into Mozilla

I have an update of this awesome answer (just not working any more with last Firefox updates), in this same thread, made by H.-Dirk Schmitt, also thanks to the answer in this other thread made by BecarioEstrella.

I just adapted the script to recent changes.

Tested in 2021 just in Firefox 85.0.1 (64bit) in Ubuntu 20.04 and 18.04.

#!/usr/bin/env bash

function usage {
  echo "Error: no certificate filename or name supplied."
  echo "Usage: $ ./installcerts.sh <certname>.pem <Cert-DB-Name>"
  exit 1

}

if [ -z "$1" ] || [ -z "$2" ]
  then
    usage
fi

certificate_file="$1"
certificate_name="$2"
for certDB in $(find  ~/.mozilla* ~/.thunderbird -name "cert9.db")
do
  cert_dir=$(dirname ${certDB});
  echo "Mozilla Firefox certificate" "install '${certificate_name}' in ${cert_dir}"
  certutil -A -n "${certificate_name}" -t "TCu,Cuw,Tuw" -i ${certificate_file} -d sql:"${cert_dir}"
done

If you want it just for Firefox, replace the line:

for certDB in $(find  ~/.mozilla* ~/.thunderbird -name "cert9.db")

By

for certDB in $(find  ~/.mozilla* -name "cert9.db")

Further readings:

Copy / Put text on the clipboard with FireFox, Safari and Chrome

Building off the excellent answer from @David from Studio.201, this works in Safari, FF, and Chrome. It also ensures no flashing could occur from the textarea by placing it off-screen.

// ================================================================================
// ClipboardClass
// ================================================================================
var ClipboardClass = (function() {


   function copyText(text) {
    // Create temp element off-screen to hold text.
        var tempElem = $('<textarea style="position: absolute; top: -8888px; left: -8888px">');
        $("body").append(tempElem);

        tempElem.val(text).select();
        document.execCommand("copy");
        tempElem.remove();
   }


    // ============================================================================
   // Class API
   // ============================================================================
    return {
        copyText: copyText
    };
})();

How to check if a character in a string is a digit or letter

By using regular expressions:

boolean isChar = character.matches("[a-zA-z]{1}");
boolean isDigit = character.matches("\\d{1}"); 

Convert JSON to Map

JSON to Map always gonna be a string/object data type. i haved GSON lib from google.

works very well and JDK 1.5 is the min requirement.

How to sanity check a date in Java

Key is df.setLenient(false);. This is more than enough for simple cases. If you are looking for a more robust (I doubt) and/or alternate libraries like joda-time then look at the answer by the user "tardate"

final static String DATE_FORMAT = "dd-MM-yyyy";

public static boolean isDateValid(String date) 
{
        try {
            DateFormat df = new SimpleDateFormat(DATE_FORMAT);
            df.setLenient(false);
            df.parse(date);
            return true;
        } catch (ParseException e) {
            return false;
        }
}

Add Insecure Registry to Docker

Anyone looking to add insecure registry on amazon linux 2: You will have to change the setting under /etc/sysconfig/docker and then restart docker daemon: here's how my /etc/sysconfig/docker looks like

# The max number of open files for the daemon itself, and all
# running containers.  The default value of 1048576 mirrors the value
# used by the systemd service unit.
DAEMON_MAXFILES=1048576

# Additional startup options for the Docker daemon, for example:
# OPTIONS="--ip-forward=true --iptables=true"
# By default we limit the number of open files per container
OPTIONS="--default-ulimit nofile=1024:4096 --insecure-registry yourinsecureregistryhostname:port"

# How many seconds the sysvinit script waits for the pidfile to appear
# when starting the daemon.
DAEMON_PIDFILE_TIMEOUT=10

ReactJS - Add custom event listener to component

First off, custom events don't play well with React components natively. So you cant just say <div onMyCustomEvent={something}> in the render function, and have to think around the problem.

Secondly, after taking a peek at the documentation for the library you're using, the event is actually fired on document.body, so even if it did work, your event handler would never trigger.

Instead, inside componentDidMount somewhere in your application, you can listen to nv-enter by adding

document.body.addEventListener('nv-enter', function (event) {
    // logic
});

Then, inside the callback function, hit a function that changes the state of the component, or whatever you want to do.

Failure during conversion to COFF: file invalid or corrupt

I am using Visual Studio 2010.

This happened to me when I installed .NET 4.5. Uninstall of .NET 4.5 and install of .NET 4.0 helped me and error messages disappeared.

How can I add a table of contents to a Jupyter / JupyterLab notebook?

As Ian already pointed out, there is a table-of-contents extension by minrk for the IPython Notebook. I had some trouble to make it work and made this IPython Notebook which semi-automatically generates the files for minrk's table of contents extension in Windows. It does not use the 'curl'-commands or links, but writes the *.js and *.css files directly into your IPython Notebook-profile-directory.

There is a section in the notebook called 'What you need to do' - follow it and have a nice floating table of contents : )

Here is an html version which already shows it: http://htmlpreview.github.io/?https://github.com/ahambi/140824-TOC/blob/master/A%20floating%20table%20of%20contents.htm

Call a Vue.js component method from outside the component

I have used a very simple solution. I have included a HTML element, that calls the method, in my Vue Component that I select, using Vanilla JS, and I trigger click!

In the Vue Component, I have included something like the following:

<span data-id="btnReload" @click="fetchTaskList()"><i class="fa fa-refresh"></i></span>

That I use using Vanilla JS:

const btnReload = document.querySelector('[data-id="btnReload"]');
btnReload.click();                

ActivityCompat.requestPermissions not showing dialog box

I had this same issue.I updated to buildToolsVersion "23.0.3" It all of a sudden worked. Hope this helps anyone having this issue.

Oracle SQL Where clause to find date records older than 30 days

Use:

SELECT *
  FROM YOUR_TABLE
 WHERE creation_date <= TRUNC(SYSDATE) - 30

SYSDATE returns the date & time; TRUNC resets the date to being as of midnight so you can omit it if you want the creation_date that is 30 days previous including the current time.

Depending on your needs, you could also look at using ADD_MONTHS:

SELECT *
  FROM YOUR_TABLE
 WHERE creation_date <= ADD_MONTHS(TRUNC(SYSDATE), -1)

JUnit assertEquals(double expected, double actual, double epsilon)

Epsilon is your "fuzz factor," since doubles may not be exactly equal. Epsilon lets you describe how close they have to be.

If you were expecting 3.14159 but would take anywhere from 3.14059 to 3.14259 (that is, within 0.001), then you should write something like

double myPi = 22.0d / 7.0d; //Don't use this in real life!
assertEquals(3.14159, myPi, 0.001);

(By the way, 22/7 comes out to 3.1428+, and would fail the assertion. This is a good thing.)

What is the difference between <html lang="en"> and <html lang="en-US">?

XML Schema requires that the xml namespace be declared and imported before using xml:lang (and other xml namespace values) RELAX NG predeclares the xml namespace, as in XML, so no additional declaration is needed.

Find size of Git repository

UPDATE git 1.8.3 introduced a more efficient way to get a rough size: git count-objects -vH (see answer by @VonC)

For different ideas of "complete size" you could use:

git bundle create tmp.bundle --all
du -sh tmp.bundle

Close (but not exact:)

git gc
du -sh .git/

With the latter, you would also be counting:

  • hooks
  • config (remotes, push branches, settings (whitespace, merge, aliases, user details etc.)
  • stashes (see Can I fetch a stash from a remote repo into a local branch? also)
  • rerere cache (which can get considerable)
  • reflogs
  • backups (from filter-branch, e.g.) and various other things (intermediate state from rebase, bisect etc.)

Does MySQL ignore null values on unique constraints?

I am unsure if the author originally was just asking whether or not this allows duplicate values or if there was an implied question here asking, "How to allow duplicate NULL values while using UNIQUE?" Or "How to only allow one UNIQUE NULL value?"

The question has already been answered, yes you can have duplicate NULL values while using the UNIQUE index.

Since I stumbled upon this answer while searching for "how to allow one UNIQUE NULL value." For anyone else who may stumble upon this question while doing the same, the rest of my answer is for you...

In MySQL you can not have one UNIQUE NULL value, however you can have one UNIQUE empty value by inserting with the value of an empty string.

Warning: Numeric and types other than string may default to 0 or another default value.

How to use gitignore command in git

If you don't have a .gitignore file. You can create a new one by

touch .gitignore

And you can exclude a folder by entering the below command in the .gitignore file

/folderName

push this file into your git repository so that when a new person clone your project he don't have to add the same again

Best way to store passwords in MYSQL database

best to use crypt for password storing in DB

example code :

$crypted_pass = crypt($password);

//$pass_from_login is the user entered password
//$crypted_pass is the encryption
if(crypt($pass_from_login,$crypted_pass)) == $crypted_pass)
{
   echo("hello user!")
}

documentation :

http://www.php.net/manual/en/function.crypt.php

Apply function to each element of a list

Sometimes you need to apply a function to the members of a list in place. The following code worked for me:

>>> def func(a, i):
...     a[i] = a[i].lower()
>>> a = ['TEST', 'TEXT']
>>> list(map(lambda i:func(a, i), range(0, len(a))))
[None, None]
>>> print(a)
['test', 'text']

Please note, the output of map() is passed to the list constructor to ensure the list is converted in Python 3. The returned list filled with None values should be ignored, since our purpose was to convert list a in place

Set TextView text from html-formatted string resource in XML

Android does not have a specification to indicate the type of resource string (e.g. text/plain or text/html). There is a workaround, however, that will allow the developer to specify this within the XML file.

  1. Define a custom attribute to specify that the android:text attribute is html.
  2. Use a subclassed TextView.

Once you define these, you can express yourself with HTML in xml files without ever having to call setText(Html.fromHtml(...)) again. I'm rather surprised that this approach is not part of the API.

This solution works to the degree that the Android studio simulator will display the text as rendered HTML.

enter image description here

res/values/strings.xml (the string resource as HTML)

<resources>
<string name="app_name">TextViewEx</string>
<string name="string_with_html"><![CDATA[
       <em>Hello</em> <strong>World</strong>!
 ]]></string>
</resources>

layout.xml (only the relevant parts)

Declare the custom attribute namespace, and add the android_ex:isHtml attribute. Also use the subclass of TextView.

<RelativeLayout
...
xmlns:android_ex="http://schemas.android.com/apk/res-auto"
...>

<tv.twelvetone.samples.textviewex.TextViewEx
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="@string/string_with_html"
    android_ex:isHtml="true"
    />
 </RelativeLayout>

res/values/attrs.xml (define the custom attributes for the subclass)

 <resources>
<declare-styleable name="TextViewEx">
    <attr name="isHtml" format="boolean"/>
    <attr name="android:text" />
</declare-styleable>
</resources>

TextViewEx.java (the subclass of TextView)

 package tv.twelvetone.samples.textviewex;

 import android.content.Context;
 import android.content.res.TypedArray;
 import android.support.annotation.Nullable;
 import android.text.Html;
 import android.util.AttributeSet;
 import android.widget.TextView;

public TextViewEx(Context context, @Nullable AttributeSet attrs) {
    super(context, attrs);
    TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.TextViewEx, 0, 0);
    try {
        boolean isHtml = a.getBoolean(R.styleable.TextViewEx_isHtml, false);
        if (isHtml) {
            String text = a.getString(R.styleable.TextViewEx_android_text);
            if (text != null) {
                setText(Html.fromHtml(text));
            }
        }
    } catch (Exception e) {
        e.printStackTrace();
    } finally {
        a.recycle();
    }
}
}

How to interpret "loss" and "accuracy" for a machine learning model

Just to clarify the Training/Validation/Test data sets: The training set is used to perform the initial training of the model, initializing the weights of the neural network.

The validation set is used after the neural network has been trained. It is used for tuning the network's hyperparameters, and comparing how changes to them affect the predictive accuracy of the model. Whereas the training set can be thought of as being used to build the neural network's gate weights, the validation set allows fine tuning of the parameters or architecture of the neural network model. It's useful as it allows repeatable comparison of these different parameters/architectures against the same data and networks weights, to observe how parameter/architecture changes affect the predictive power of the network.

Then the test set is used only to test the predictive accuracy of the trained neural network on previously unseen data, after training and parameter/architecture selection with the training and validation data sets.

Assignment inside lambda expression in Python

If instead of flag = True we can do an import instead, then I think this meets the criteria:

>>> from itertools import count
>>> a = ['hello', '', 'world', '', '', '', 'bob']
>>> filter(lambda L, j=count(): L or not next(j), a)
['hello', '', 'world', 'bob']

Or maybe the filter is better written as:

>>> filter(lambda L, blank_count=count(1): L or next(blank_count) == 1, a)

Or, just for a simple boolean, without any imports:

filter(lambda L, use_blank=iter([True]): L or next(use_blank, False), a)

How to check SQL Server version

select charindex(  'Express',@@version)

if this value is 0 is not a express edition

Using global variables in a function

You need to reference the global variable in every function you want to use.

As follows:

var = "test"

def printGlobalText():
    global var #wWe are telling to explicitly use the global version
    var = "global from printGlobalText fun."
    print "var from printGlobalText: " + var

def printLocalText():
    #We are NOT telling to explicitly use the global version, so we are creating a local variable
    var = "local version from printLocalText fun"
    print "var from printLocalText: " + var

printGlobalText()
printLocalText()
"""
Output Result:
var from printGlobalText: global from printGlobalText fun.
var from printLocalText: local version from printLocalText
[Finished in 0.1s]
"""

Simple export and import of a SQLite database on Android

Import and Export of a SQLite database on Android

Here is my function for export database into device storage

private void exportDB(){
    String DatabaseName = "Sycrypter.db";
    File sd = Environment.getExternalStorageDirectory();
    File data = Environment.getDataDirectory();
    FileChannel source=null;
    FileChannel destination=null;
    String currentDBPath = "/data/"+ "com.synnlabz.sycryptr" +"/databases/"+DatabaseName ;
    String backupDBPath = SAMPLE_DB_NAME;
    File currentDB = new File(data, currentDBPath);
    File backupDB = new File(sd, backupDBPath);
    try {
        source = new FileInputStream(currentDB).getChannel();
        destination = new FileOutputStream(backupDB).getChannel();
        destination.transferFrom(source, 0, source.size());
        source.close();
        destination.close();
        Toast.makeText(this, "Your Database is Exported !!", Toast.LENGTH_LONG).show();
    } catch(IOException e) {
        e.printStackTrace();
    }
}

Here is my function for import database from device storage into android application

private void importDB(){
    String dir=Environment.getExternalStorageDirectory().getAbsolutePath();
    File sd = new File(dir);
    File data = Environment.getDataDirectory();
    FileChannel source = null;
    FileChannel destination = null;
    String backupDBPath = "/data/com.synnlabz.sycryptr/databases/Sycrypter.db";
    String currentDBPath = "Sycrypter.db";
    File currentDB = new File(sd, currentDBPath);
    File backupDB = new File(data, backupDBPath);

    try {
        source = new FileInputStream(currentDB).getChannel();
        destination = new FileOutputStream(backupDB).getChannel();
        destination.transferFrom(source, 0, source.size());
        source.close();
        destination.close();
        Toast.makeText(this, "Your Database is Imported !!", Toast.LENGTH_SHORT).show();
    } catch (IOException e) {
        e.printStackTrace();
    }
}

How to rename a directory/folder on GitHub website?

As a newer user to git, I took the following approach. From the command line, I was able to rename a folder by creating a new folder, copying the files to it, adding and commiting locally and pushing. These are my steps:

$mkdir newfolder 
$cp oldfolder/* newfolder
$git add newfolder 
$git commit -m 'start rename'     
$git push                             #New Folder appears on Github      
$git rm -r oldfolder
$git commit -m 'rename complete' 
$git push                             #Old Folder disappears on Github  

Probably a better way, but it worked for me.

Setting the default value of a DateTime Property to DateTime.Now inside the System.ComponentModel Default Value Attrbute

I think you can do this using StoreGeneratedPattern = Identity (set in the model designer properties window).

I wouldn't have guessed that would be how to do it, but while trying to figure it out I noticed that some of my date columns were already defaulting to CURRENT_TIMESTAMP() and some weren't. Checking the model, I see that the only difference between the two columns besides the name is that the one getting the default value has StoreGeneratedPattern set to Identity.

I wouldn't have expected that to be the way, but reading the description, it sort of makes sense:

Determines if the corresponding column in the database will be auto-generated during insert and update operations.

Also, while this does make the database column have a default value of "now", I guess it does not actually set the property to be DateTime.Now in the POCO. This hasn't been an issue for me as I have a customized .tt file that already sets all of my date columns to DateTime.Now automatically (it's actually not hard to modify the .tt file yourself, especially if you have ReSharper and get a syntax highlighting plugin. (Newer versions of VS may already syntax highlight .tt files, not sure.))

The issue for me was: how do I get the database column to have a default so that existing queries that omit that column will still work? And the above setting worked for that.

I haven't tested it yet but it's also possible that setting this will interfere with setting your own explicit value. (I only stumbled upon this in the first place because EF6 Database First wrote the model for me this way.)

What techniques can be used to define a class in JavaScript, and what are their trade-offs?

If you're going for simple, you can avoid the "new" keyword entirely and just use factory methods. I prefer this, sometimes, because I like using JSON to create objects.

function getSomeObj(var1, var2){
  var obj = {
     instancevar1: var1,
     instancevar2: var2,
     someMethod: function(param)
     {  
          //stuff; 
     }
  };
  return obj;
}

var myobj = getSomeObj("var1", "var2");
myobj.someMethod("bla");

I'm not sure what the performance hit is for large objects, though.

Refresh Page and Keep Scroll Position

This might be useful for refreshing also. But if you want to keep track of position on the page before you click on a same position.. The following code will help.

Also added a data-confirm for prompting the user if they really want to do that..

Note: I'm using jQuery and js-cookie.js to store cookie info.

$(document).ready(function() {
    // make all links with data-confirm prompt the user first.
    $('[data-confirm]').on("click", function (e) {
        e.preventDefault();
        var msg = $(this).data("confirm");
        if(confirm(msg)==true) {
            var url = this.href;
            if(url.length>0) window.location = url;
            return true;
        }
        return false;
    });

    // on certain links save the scroll postion.
    $('.saveScrollPostion').on("click", function (e) {
        e.preventDefault();
        var currentYOffset = window.pageYOffset;  // save current page postion.
        Cookies.set('jumpToScrollPostion', currentYOffset);
        if(!$(this).attr("data-confirm")) {  // if there is no data-confirm on this link then trigger the click. else we have issues.
            var url = this.href;
            window.location = url;
            //$(this).trigger('click');  // continue with click event.
        }
    });

    // check if we should jump to postion.
    if(Cookies.get('jumpToScrollPostion') !== "undefined") {
        var jumpTo = Cookies.get('jumpToScrollPostion');
        window.scrollTo(0, jumpTo);
        Cookies.remove('jumpToScrollPostion');  // and delete cookie so we don't jump again.
    }
});

A example of using it like this.

<a href='gotopage.html' class='saveScrollPostion' data-confirm='Are you sure?'>Goto what the heck</a>

Send JSON data with jQuery

Because you haven't specified neither request content type, nor correct JSON request. Here's the correct way to send a JSON request:

var arr = { City: 'Moscow', Age: 25 };
$.ajax({
    url: 'Ajax.ashx',
    type: 'POST',
    data: JSON.stringify(arr),
    contentType: 'application/json; charset=utf-8',
    dataType: 'json',
    async: false,
    success: function(msg) {
        alert(msg);
    }
});

Things to notice:

  • Usage of the JSON.stringify method to convert a javascript object into a JSON string which is native and built-into modern browsers. If you want to support older browsers you might need to include json2.js
  • Specifying the request content type using the contentType property in order to indicate to the server the intent of sending a JSON request
  • The dataType: 'json' property is used for the response type you expect from the server. jQuery is intelligent enough to guess it from the server Content-Type response header. So if you have a web server which respects more or less the HTTP protocol and responds with Content-Type: application/json to your request jQuery will automatically parse the response into a javascript object into the success callback so that you don't need to specify the dataType property.

Things to be careful about:

  • What you call arr is not an array. It is a javascript object with properties (City and Age). Arrays are denoted with [] in javascript. For example [{ City: 'Moscow', Age: 25 }, { City: 'Paris', Age: 30 }] is an array of 2 objects.

Unable to execute dex: Multiple dex files define Lcom/myapp/R$array;

I had two related but not identical guava libraries in the /libs directory, after I removed one, the problem went away.

How can I scroll up more (increase the scroll buffer) in iTerm2?

Solution: In order to increase your buffer history on iterm bash terminal you've got two options:

Go to iterm -> Preferences -> Profiles -> Terminal Tab -> Scrollback Buffer (section)

Option 1. select the checkbox Unlimited scrollback

Option 2. type the selected Scrollback lines numbers you'd like your terminal buffer to cache (See image below)

enter image description here

REST API 404: Bad URI, or Missing Resource?

For this scenario HTTP 404 is response code for the response from the REST API Like 400, 401, 404 , 422 unprocessable entity

use the Exception handling to check the full exception message.

try{
  // call the rest api
} catch(RestClientException e) {
     //process exception
     if(e instanceof HttpStatusCodeException){
        String responseText=((HttpStatusCodeException)e).getResponseBodyAsString();
         //now you have the response, construct json from it, and extract the errors
         System.out.println("Exception :" +responseText);
     }

}

This exception block give you the proper message thrown by the REST API

Android - How To Override the "Back" button so it doesn't Finish() my Activity?

just do this

@Override
public void onBackPressed() {
    super.onBackPressed();
}

Aligning a button to the center

You should use something like this:

<div style="text-align:center">  
    <input type="submit" />  
</div>  

Or you could use something like this. By giving the element a width and specifying auto for the left and right margins the element will center itself in its parent.

<input type="submit" style="width: 300px; margin: 0 auto;" />

How to change Visual Studio 2012,2013 or 2015 License Key?

For those of you using Visual Studio 2017 Professional, the registry key is:

HKCR\Licenses\5C505A59-E312-4B89-9508-E162F8150517

I also recommend you first export the registry key, before you delete it, so you'll have a backup if you accidentally delete the wrong key.

How to declare a global variable in php?

$GLOBALS[] is the right solution, but since we're talking about alternatives, a function can also do this job easily:

function capital() {
    return my_var() . ' is the capital of Italy';
}

function my_var() {
    return 'Rome';
}

Align HTML input fields by :

in my case i always put these stuffs in a p tag like

<p> name : < input type=text /> </p>

and so on and then applying the css like

p {
  text-align:left;
}

p input {
  float:right;
}

You need to specify the width of the p tag.because the input tags will float all the way right.

This css will also affect the submit button. You need to override the rule for this tag.