Programs & Examples On #User agent

A user agent is a piece of software (a software agent) that acts on behalf of a user. The term is often used to refer to browsers, and other software that sends network requests. In the HTTP protocol, a user agent identifies itself to the server using a user-agent string. The user-agent string is a string in the header of an HTTP request that identifies the browser, version, device, os, and other information about the device from which the request came.

What is the iOS 6 user agent string?

Some more:

Mozilla/5.0 (iPhone; CPU iPhone OS 6_1_3 like Mac OS X) AppleWebKit/536.26 (KHTML, like Gecko) Version/6.0 Mobile/10B329 Safari/8536.25

Mozilla/5.0 (iPhone; CPU iPhone OS 6_1_4 like Mac OS X) AppleWebKit/536.26 (KHTML, like Gecko) Version/6.0 Mobile/10B350 Safari/8536.25

Setting user agent of a java URLConnection

Just for clarification: setRequestProperty("User-Agent", "Mozilla ...") now works just fine and doesn't append java/xx at the end! At least with Java 1.6.30 and newer.

I listened on my machine with netcat(a port listener):

$ nc -l -p 8080

It simply listens on the port, so you see anything which gets requested, like raw http-headers.

And got the following http-headers without setRequestProperty:

GET /foobar HTTP/1.1
User-Agent: Java/1.6.0_30
Host: localhost:8080
Accept: text/html, image/gif, image/jpeg, *; q=.2, */*; q=.2
Connection: keep-alive

And WITH setRequestProperty:

GET /foobar HTTP/1.1
User-Agent: Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.4; en-US; rv: Gecko/20100316 Firefox/3.6.2
Host: localhost:8080
Accept: text/html, image/gif, image/jpeg, *; q=.2, */*; q=.2
Connection: keep-alive

As you can see the user agent was properly set.

Full example:


public class TestUrlOpener {

    public static void main(String[] args) throws IOException {
        URL url = new URL("http://localhost:8080/foobar");
        URLConnection hc = url.openConnection();
        hc.setRequestProperty("User-Agent", "Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.4; en-US; rv: Gecko/20100316 Firefox/3.6.2");



How to use curl to get a GET request exactly same as using Chrome?

Check the HTTP headers that chrome is sending with the request (Using browser extension or proxy) then try sending the same headers with CURL - Possibly one at a time till you figure out which header(s) makes the request work.

curl -A [user-agent] -H [headers] ""

Get operating system info

If you want very few info like a class in your html for common browsers for instance, you could use:

function get_browser()
    $browser = '';
    $ua = strtolower($_SERVER['HTTP_USER_AGENT']);
    if (preg_match('~(?:msie ?|trident.+?; ?rv: ?)(\d+)~', $ua, $matches)) $browser = 'ie ie'.$matches[1];
    elseif (preg_match('~(safari|chrome|firefox)~', $ua, $matches)) $browser = $matches[1];

    return $browser;

which will return 'safari' or 'firefox' or 'chrome', or 'ie ie8', 'ie ie9', 'ie ie10', 'ie ie11'.

Change user-agent for Selenium web-driver

There is no way in Selenium to read the request or response headers. You could do it by instructing your browser to connect through a proxy that records this kind of information.

Setting the User Agent in Firefox

The usual way to change the user agent for Firefox is to set the variable "general.useragent.override" in your Firefox profile. Note that this is independent from Selenium.

You can direct Selenium to use a profile different from the default one, like this:

from selenium import webdriver
profile = webdriver.FirefoxProfile()
profile.set_preference("general.useragent.override", "whatever you want")
driver = webdriver.Firefox(profile)

Setting the User Agent in Chrome

With Chrome, what you want to do is use the user-agent command line option. Again, this is not a Selenium thing. You can invoke Chrome at the command line with chrome --user-agent=foo to set the agent to the value foo.

With Selenium you set it like this:

from selenium import webdriver
from import Options
opts = Options()
opts.add_argument("user-agent=whatever you want")

driver = webdriver.Chrome(chrome_options=opts)

Both methods above were tested and found to work. I don't know about other browsers.

Getting the User Agent

Selenium does not have methods to query the user agent from an instance of WebDriver. Even in the case of Firefox, you cannot discover the default user agent by checking what general.useragent.override would be if not set to a custom value. (This setting does not exist before it is set to some value.)

Once the browser is started, however, you can get the user agent by executing:

agent = driver.execute_script("return navigator.userAgent")

The agent variable will contain the user agent.

What is the iPad user agent?

From a real device:

Mozilla/5.0 (iPad; U; CPU OS OS 3_2 like Mac OS X; en-us) AppleWebKit/531.21.10 (KHTML, like Gecko) Version/4.0.4 Mobile/7B367 Safari/531.21.10

How does HTTP_USER_AGENT work?

Visit that page, it'll give you a good explanation of each element of your user agent.


MozillaProductSlice. Claims to be a Mozilla based user agent, which is only true for Gecko browsers like Firefox and Netscape. For all other user agents it means 'Mozilla-compatible'. In modern browsers, this is only used for historical reasons. It has no real meaning anymore

Changing user agent on urllib2.urlopen

All these should work in theory, but (with Python 2.7.2 on Windows at least) any time you send a custom User-agent header, urllib2 doesn't send that header. If you don't try to send a User-agent header, it sends the default Python / urllib2

None of these methods seem to work for adding User-agent but they work for other headers:

opener = urllib2.build_opener(proxy)
opener.addheaders = {'User-agent':'Custom user agent'}

request = urllib2.Request(url, headers={'User-agent':'Custom user agent'})

request.headers['User-agent'] = 'Custom user agent'

request.add_header('User-agent', 'Custom user agent')

Determine a user's timezone

Try this PHP code:

    $ip = $_SERVER['REMOTE_ADDR'];
    $json = file_get_contents("" . $ip . "&full=true");
    $json = json_decode($json,true);
    $timezone = $json['LocalTimeZone'];

Auto detect mobile browser (via user-agent?)

You can detect mobile clients simply through navigator.userAgent , and load alternate scripts based on the detected client type as:

 $(document).ready(function(e) {

          || navigator.userAgent.match(/webOS/i)
          || navigator.userAgent.match(/iPhone/i)
          || navigator.userAgent.match(/iPad/i)
          || navigator.userAgent.match(/iPod/i)
          || navigator.userAgent.match(/BlackBerry/i)
          || navigator.userAgent.match(/Windows Phone/i)) {

         //write code for your mobile clients here.

          var jsScript = document.createElement("script");
          jsScript.setAttribute("type", "text/javascript");
          jsScript.setAttribute("src", "js/alternate_js_file.js");
          document.getElementsByTagName("head")[0].appendChild(jsScript );

          var cssScript = document.createElement("link");
          cssScript.setAttribute("rel", "stylesheet");
          cssScript.setAttribute("type", "text/css");
          cssScript.setAttribute("href", "css/alternate_css_file.css");

         // write code for your desktop clients here


How to find the operating system version using JavaScript?

I started to write a Script to read OS and browser version that can be tested on Fiddle. Feel free to use and extend.
Breaking Change:
Since September 2020 the new Edge gets detected. So 'Microsoft Edge' is the new version based on Chromium and the old Edge is now detected as 'Microsoft Legacy Edge'!

 * JavaScript Client Detection
 * (C) viazenetti GmbH (Christian Ludwig)
(function (window) {
        var unknown = '-';

        // screen
        var screenSize = '';
        if (screen.width) {
            width = (screen.width) ? screen.width : '';
            height = (screen.height) ? screen.height : '';
            screenSize += '' + width + " x " + height;

        // browser
        var nVer = navigator.appVersion;
        var nAgt = navigator.userAgent;
        var browser = navigator.appName;
        var version = '' + parseFloat(navigator.appVersion);
        var majorVersion = parseInt(navigator.appVersion, 10);
        var nameOffset, verOffset, ix;

        // Opera
        if ((verOffset = nAgt.indexOf('Opera')) != -1) {
            browser = 'Opera';
            version = nAgt.substring(verOffset + 6);
            if ((verOffset = nAgt.indexOf('Version')) != -1) {
                version = nAgt.substring(verOffset + 8);
        // Opera Next
        if ((verOffset = nAgt.indexOf('OPR')) != -1) {
            browser = 'Opera';
            version = nAgt.substring(verOffset + 4);
        // Legacy Edge
        else if ((verOffset = nAgt.indexOf('Edge')) != -1) {
            browser = 'Microsoft Legacy Edge';
            version = nAgt.substring(verOffset + 5);
        // Edge (Chromium)
        else if ((verOffset = nAgt.indexOf('Edg')) != -1) {
            browser = 'Microsoft Edge';
            version = nAgt.substring(verOffset + 4);
        // MSIE
        else if ((verOffset = nAgt.indexOf('MSIE')) != -1) {
            browser = 'Microsoft Internet Explorer';
            version = nAgt.substring(verOffset + 5);
        // Chrome
        else if ((verOffset = nAgt.indexOf('Chrome')) != -1) {
            browser = 'Chrome';
            version = nAgt.substring(verOffset + 7);
        // Safari
        else if ((verOffset = nAgt.indexOf('Safari')) != -1) {
            browser = 'Safari';
            version = nAgt.substring(verOffset + 7);
            if ((verOffset = nAgt.indexOf('Version')) != -1) {
                version = nAgt.substring(verOffset + 8);
        // Firefox
        else if ((verOffset = nAgt.indexOf('Firefox')) != -1) {
            browser = 'Firefox';
            version = nAgt.substring(verOffset + 8);
        // MSIE 11+
        else if (nAgt.indexOf('Trident/') != -1) {
            browser = 'Microsoft Internet Explorer';
            version = nAgt.substring(nAgt.indexOf('rv:') + 3);
        // Other browsers
        else if ((nameOffset = nAgt.lastIndexOf(' ') + 1) < (verOffset = nAgt.lastIndexOf('/'))) {
            browser = nAgt.substring(nameOffset, verOffset);
            version = nAgt.substring(verOffset + 1);
            if (browser.toLowerCase() == browser.toUpperCase()) {
                browser = navigator.appName;
        // trim the version string
        if ((ix = version.indexOf(';')) != -1) version = version.substring(0, ix);
        if ((ix = version.indexOf(' ')) != -1) version = version.substring(0, ix);
        if ((ix = version.indexOf(')')) != -1) version = version.substring(0, ix);

        majorVersion = parseInt('' + version, 10);
        if (isNaN(majorVersion)) {
            version = '' + parseFloat(navigator.appVersion);
            majorVersion = parseInt(navigator.appVersion, 10);

        // mobile version
        var mobile = /Mobile|mini|Fennec|Android|iP(ad|od|hone)/.test(nVer);

        // cookie
        var cookieEnabled = (navigator.cookieEnabled) ? true : false;

        if (typeof navigator.cookieEnabled == 'undefined' && !cookieEnabled) {
            document.cookie = 'testcookie';
            cookieEnabled = (document.cookie.indexOf('testcookie') != -1) ? true : false;

        // system
        var os = unknown;
        var clientStrings = [
            {s:'Windows 10', r:/(Windows 10.0|Windows NT 10.0)/},
            {s:'Windows 8.1', r:/(Windows 8.1|Windows NT 6.3)/},
            {s:'Windows 8', r:/(Windows 8|Windows NT 6.2)/},
            {s:'Windows 7', r:/(Windows 7|Windows NT 6.1)/},
            {s:'Windows Vista', r:/Windows NT 6.0/},
            {s:'Windows Server 2003', r:/Windows NT 5.2/},
            {s:'Windows XP', r:/(Windows NT 5.1|Windows XP)/},
            {s:'Windows 2000', r:/(Windows NT 5.0|Windows 2000)/},
            {s:'Windows ME', r:/(Win 9x 4.90|Windows ME)/},
            {s:'Windows 98', r:/(Windows 98|Win98)/},
            {s:'Windows 95', r:/(Windows 95|Win95|Windows_95)/},
            {s:'Windows NT 4.0', r:/(Windows NT 4.0|WinNT4.0|WinNT|Windows NT)/},
            {s:'Windows CE', r:/Windows CE/},
            {s:'Windows 3.11', r:/Win16/},
            {s:'Android', r:/Android/},
            {s:'Open BSD', r:/OpenBSD/},
            {s:'Sun OS', r:/SunOS/},
            {s:'Chrome OS', r:/CrOS/},
            {s:'Linux', r:/(Linux|X11(?!.*CrOS))/},
            {s:'iOS', r:/(iPhone|iPad|iPod)/},
            {s:'Mac OS X', r:/Mac OS X/},
            {s:'Mac OS', r:/(Mac OS|MacPPC|MacIntel|Mac_PowerPC|Macintosh)/},
            {s:'QNX', r:/QNX/},
            {s:'UNIX', r:/UNIX/},
            {s:'BeOS', r:/BeOS/},
            {s:'OS/2', r:/OS\/2/},
            {s:'Search Bot', r:/(nuhk|Googlebot|Yammybot|Openbot|Slurp|MSNBot|Ask Jeeves\/Teoma|ia_archiver)/}
        for (var id in clientStrings) {
            var cs = clientStrings[id];
            if (cs.r.test(nAgt)) {
                os = cs.s;

        var osVersion = unknown;

        if (/Windows/.test(os)) {
            osVersion = /Windows (.*)/.exec(os)[1];
            os = 'Windows';

        switch (os) {
            case 'Mac OS':
            case 'Mac OS X':
            case 'Android':
                osVersion = /(?:Android|Mac OS|Mac OS X|MacPPC|MacIntel|Mac_PowerPC|Macintosh) ([\.\_\d]+)/.exec(nAgt)[1];

            case 'iOS':
                osVersion = /OS (\d+)_(\d+)_?(\d+)?/.exec(nVer);
                osVersion = osVersion[1] + '.' + osVersion[2] + '.' + (osVersion[3] | 0);
        // flash (you'll need to include swfobject)
        /* script src="//" */
        var flashVersion = 'no check';
        if (typeof swfobject != 'undefined') {
            var fv = swfobject.getFlashPlayerVersion();
            if (fv.major > 0) {
                flashVersion = fv.major + '.' + fv.minor + ' r' + fv.release;
            else  {
                flashVersion = unknown;

    window.jscd = {
        screen: screenSize,
        browser: browser,
        browserVersion: version,
        browserMajorVersion: majorVersion,
        mobile: mobile,
        os: os,
        osVersion: osVersion,
        cookies: cookieEnabled,
        flashVersion: flashVersion

    'OS: ' + jscd.os +' '+ jscd.osVersion + '\n' +
    'Browser: ' + jscd.browser +' '+ jscd.browserMajorVersion +
      ' (' + jscd.browserVersion + ')\n' + 
    'Mobile: ' + + '\n' +
    'Flash: ' + jscd.flashVersion + '\n' +
    'Cookies: ' + jscd.cookies + '\n' +
    'Screen Size: ' + jscd.screen + '\n\n' +
    'Full User Agent: ' + navigator.userAgent

How to get user agent in PHP

You could also use the php native funcion get_browser()

IMPORTANT NOTE: You should have a browscap.ini file.

What is the iOS 5.0 user agent string?

I use the following to detect different mobile devices, viewport and screen. Works quite well for me, might be helpful to others:

var pixelRatio = window.devicePixelRatio || 1;

var viewport = {
    width: window.innerWidth,
    height: window.innerHeight

var screen = {
    width: window.screen.availWidth * pixelRatio,
    height: window.screen.availHeight * pixelRatio

var iPhone = /iPhone/i.test(navigator.userAgent);
var iPhone4 = (iPhone && pixelRatio == 2);
var iPhone5 = /iPhone OS 5_0/i.test(navigator.userAgent);
var iPad = /iPad/i.test(navigator.userAgent);
var android = /android/i.test(navigator.userAgent);
var webos = /hpwos/i.test(navigator.userAgent);
var iOS = iPhone || iPad;
var mobile = iOS || android || webos;

window.devicePixelRatio is the ratio between physical pixels and device-independent pixels (dips) on the device. window.devicePixelRatio = physical pixels / dips.

More info here.

How to use Python requests to fake a browser visit a.k.a and generate User Agent?

The root of the answer is that the person asking the question needs to have a JavaScript interpreter to get what they are after. What I have found is I am able to get all of the information I wanted on a website in json before it was interpreted by JavaScript. This has saved me a ton of time in what would be parsing html hoping each webpage is in the same format.

So when you get a response from a website using requests really look at the html/text because you might find the javascripts JSON in the footer ready to be parsed.

Detect IE version (prior to v9) in JavaScript

The most comprehensive JS script I found to check for versions of IE is The entire library is at

With IE10, conditional statements are no longer supported.

With IE11, the user agent no longer contains MSIE. Also, using the user agent is not reliable because that can be modified.

Using the PluginDetect JS script, you can detect for IE and detect the exact versions by using very specific and well-crafted code that targets specific IE versions. This is very useful when you care exactly what version of browser you are working with.

Sites not accepting wget user agent header

I created a ~/.wgetrc file with the following content (obtained from but with a newer user agent, because otherwise it didn’t work always):

header = Accept-Language: en-us,en;q=0.5
header = Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
header = Connection: keep-alive
user_agent = Mozilla/5.0 (X11; Fedora; Linux x86_64; rv:40.0) Gecko/20100101 Firefox/40.0
referer = /
robots = off

Now I’m able to download from most (all?) file-sharing (streaming video) sites.

How to scale an Image in ImageView to keep the aspect ratio

If you want an ImageView that both scales up and down while keeping the proper aspect ratio, add this to your XML:


Add this to your code:

// We need to adjust the height if the width of the bitmap is
// smaller than the view width, otherwise the image will be boxed.
final double viewWidthToBitmapWidthRatio = (double)image.getWidth() / (double)bitmap.getWidth();
image.getLayoutParams().height = (int) (bitmap.getHeight() * viewWidthToBitmapWidthRatio);

It took me a while to get this working, but this appears to work in the cases both where the image is smaller than the screen width and larger than the screen width, and it does not box the image.

ERROR Error: StaticInjectorError(AppModule)[UserformService -> HttpClient]:

Simply i have import in appmodule.ts

import { HttpClientModule } from '@angular/common/http';
  imports: [
     HttpClientModule  <<<this 

My problem resolved

Input type DateTime - Value format?

This works for setting the value of the INPUT:

strftime('%Y-%m-%dT%H:%M:%S', time())

How to get name of the computer in VBA?

Looks like I'm late to the game, but this is a common question...

This is probably the code you want.

Please note that this code is in the public domain, from Usenet, MSDN, and the Excellerando blog.

Public Function ComputerName() As String
'' Returns the host name

'' Uses late-binding: bad for performance and stability, useful for 
'' code portability. The correct declaration is:

'   Dim objNetwork  As IWshRuntimeLibrary.WshNetwork
'   Set objNetwork = New IWshRuntimeLibrary.WshNetwork

    Dim objNetwork As Object
    Set objNetwork = CreateObject("WScript.Network")

    ComputerName = objNetwork.ComputerName
    Set objNetwork = Nothing

End Function

You'll probably need this, too:

Public Function UserName(Optional WithDomain As Boolean = False) As String
'' Returns the user's network name

'' Uses late-binding: bad for performance and stability, useful for
'' code portability. The correct declaration is:

'   Dim objNetwork  As IWshRuntimeLibrary.WshNetwork
'   Set objNetwork = New IWshRuntimeLibrary.WshNetwork

    Dim objNetwork As Object
    Set objNetwork = CreateObject("WScript.Network")

    If WithDomain Then
        UserName = objNetwork.UserDomain & "\" & objNetwork.UserName
        UserName = objNetwork.UserName
    End If
    Set objNetwork = Nothing

End Function

SQL Server Escape an Underscore

T-SQL Reference for LIKE:

You can use the wildcard pattern matching characters as literal characters. To use a wildcard character as a literal character, enclose the wildcard character in brackets. The following table shows several examples of using the LIKE keyword and the [ ] wildcard characters.

For your case:

... LIKE '%[_]d'

VBA for clear value in specific range of cell and protected cell from being wash away formula

Not sure its faster with VBA - the fastest way to do it in the normal Excel programm would be:

  1. Ctrl-G
  2. A1:X50 Enter
  3. Delete

Unless you have to do this very often, entering and then triggering the VBAcode is more effort.

And in case you only want to delete formulas or values, you can insert Ctrl-G, Alt-S to select Goto Special and here select Formulas or Values.

Get the string representation of a DOM node

Under FF you can use the XMLSerializer object to serialize XML into a string. IE gives you an xml property of a node. So you can do the following:

function xml2string(node) {
   if (typeof(XMLSerializer) !== 'undefined') {
      var serializer = new XMLSerializer();
      return serializer.serializeToString(node);
   } else if (node.xml) {
      return node.xml;

Check if a number is odd or even in python

It shouldn't matter if the word has an even or odd amount fo letters:

def is_palindrome(word):
    if word == word[::-1]:
        return True
        return False

Difference between Constructor and ngOnInit

Short and simple answer would be,

Constructor : constructor is a default method runs (by default) when component is being constructed. When you create an instance of a class that time also constructor(default method) would be called. So in other words, when the component is being constructed or/and an instance is created constructor(default method) is called and relevant code is written within is called. Basically and generally in Angular2, it used to inject things like services when the component is being constructed for further use.

OnInit: ngOnInit is component's life cycle hook which runs first after constructor(default method) when the component is being initialized.

So, Your constructor will be called first and Oninit will be called later after constructor method.


import {Cmomponent, OnInit} from 'angular2/core';
import {ExternalService} from '../externalService';

export class app implements OnInit{

     // this.myService.someMethod() 

Resources: LifeCycle hook

You can check this small demo which shows an implementation of both things.

How to get the full url in Express?

Just the code below was enough for me!

const baseUrl = `${request.protocol}://${}`;

laravel-5 passing variable to JavaScript

Is very easy, I use this code:


$langs = Language::all()->toArray();
return view('NAATIMockTest.Admin.Language.index', compact('langs'));


<script type="text/javascript">
    var langs = <?php echo json_decode($langs); ?>;

hope it has been helpful, regards!

How to add Apache HTTP API (legacy) as compile-time dependency to build.grade for Android M?

FWIW the removal of Apache library was foreshadowed a while ago. Our good friend Jesse Wilson gave us a clue back in 2011:

Google stopped working on ApacheHTTPClient a while ago, so any library that is still relying upon that should be put onto the list of deprecated libraries unless the maintainers update their code.

<rant> I can't tell you how many technical arguments I've had with people who insisted on sticking with Apache HTTP client. There are some major apps that are going to break because management at my not-to-be-named previous employers didn't listen to their top engineers or knew what they were talking about when they ignored the warning ... but, water under the bridge.

I win.


How can I send mail from an iPhone application

On iOS 3.0 and later you should use the MFMailComposeViewController class, and the MFMailComposeViewControllerDelegate protocol, that is tucked away in the MessageUI framework.

First add the framework and import:

#import <MessageUI/MFMailComposeViewController.h>

Then, to send a message:

MFMailComposeViewController* controller = [[MFMailComposeViewController alloc] init];
controller.mailComposeDelegate = self;
[controller setSubject:@"My Subject"];
[controller setMessageBody:@"Hello there." isHTML:NO]; 
if (controller) [self presentModalViewController:controller animated:YES];
[controller release];

Then the user does the work and you get the delegate callback in time:

- (void)mailComposeController:(MFMailComposeViewController*)controller  
  if (result == MFMailComposeResultSent) {
    NSLog(@"It's away!");
  [self dismissModalViewControllerAnimated:YES];

Remember to check if the device is configured for sending email:

if ([MFMailComposeViewController canSendMail]) {
  // Show the composer
} else {
  // Handle the error

How do I make a transparent border with CSS?

You can use "transparent" as a colour. In some versions of IE, that comes up as black, but I've not tested it out since the IE6 days.

File Upload in WebView

Webview - Single & Multiple files choose

you needs two minutes to implement this code:


implementation 'com.github.angads25:filepicker:1.1.1'

java code:

import android.annotation.SuppressLint;
import android.content.DialogInterface;
import android.content.Intent;
import android.os.Build;
import android.os.Bundle;
import android.util.Log;
import android.view.KeyEvent;
import android.view.View;
import android.webkit.ValueCallback;
import android.webkit.WebChromeClient;
import android.webkit.WebSettings;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import android.widget.ProgressBar;
import android.widget.Toast;

import com.bivoiclient.utils.Constants;
import com.github.angads25.filepicker.controller.DialogSelectionListener;
import com.github.angads25.filepicker.model.DialogConfigs;
import com.github.angads25.filepicker.model.DialogProperties;
import com.github.angads25.filepicker.view.FilePickerDialog;


public class WebBrowserScreen extends Activity {

    private WebView webView;
    private ValueCallback<Uri[]> mUploadMessage;
    private FilePickerDialog dialog;
    private String LOG_TAG = "DREG";
    private Uri[] results;

    protected void onCreate(Bundle savedInstanceState) {

        webView = findViewById(;
        WebSettings webSettings = webView.getSettings();
        webView.setWebViewClient(new PQClient());
        webView.setWebChromeClient(new PQChromeClient());
        if (Build.VERSION.SDK_INT >= 19) {
            webView.setLayerType(View.LAYER_TYPE_HARDWARE, null);
        } else {
            webView.setLayerType(View.LAYER_TYPE_SOFTWARE, null);



    private void openFileSelectionDialog() {

        if (null != dialog && dialog.isShowing()) {

        //Create a DialogProperties object.
        final DialogProperties properties = new DialogProperties();

        //Instantiate FilePickerDialog with Context and DialogProperties.
        dialog = new FilePickerDialog(WebBrowserScreen.this, properties);
        dialog.setTitle("Select a File");
        properties.selection_mode = DialogConfigs.MULTI_MODE; // for multiple files
//        properties.selection_mode = DialogConfigs.SINGLE_MODE; // for single file
        properties.selection_type = DialogConfigs.FILE_SELECT;

        //Method handle selected files.
        dialog.setDialogSelectionListener(new DialogSelectionListener() {
            public void onSelectedFilePaths(String[] files) {
                results = new Uri[files.length];
                for (int i = 0; i < files.length; i++) {
                    String filePath = new File(files[i]).getAbsolutePath();
                    if (!filePath.startsWith("file://")) {
                        filePath = "file://" + filePath;
                    results[i] = Uri.parse(filePath);
                    Log.d(LOG_TAG, "file path: " + filePath);
                    Log.d(LOG_TAG, "file uri: " + String.valueOf(results[i]));
                mUploadMessage = null;
        dialog.setOnCancelListener(new DialogInterface.OnCancelListener() {
            public void onCancel(DialogInterface dialogInterface) {
                if (null != mUploadMessage) {
                    if (null != results && results.length >= 1) {
                    } else {
                mUploadMessage = null;
        dialog.setOnDismissListener(new DialogInterface.OnDismissListener() {
            public void onDismiss(DialogInterface dialogInterface) {
                if (null != mUploadMessage) {
                    if (null != results && results.length >= 1) {
                    } else {
                mUploadMessage = null;


    public class PQChromeClient extends WebChromeClient {

        public boolean onShowFileChooser(WebView webView, ValueCallback<Uri[]> filePathCallback, FileChooserParams fileChooserParams) {
            // Double check that we don't have any existing callbacks
            if (mUploadMessage != null) {
            mUploadMessage = filePathCallback;


            return true;


    //Add this method to show Dialog when the required permission has been granted to the app.
    public void onRequestPermissionsResult(int requestCode, @NonNull String permissions[], @NonNull int[] grantResults) {
        switch (requestCode) {
            case FilePickerDialog.EXTERNAL_READ_PERMISSION_GRANT: {
                if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                    if (dialog != null) {
                } else {
                    //Permission has not been granted. Notify the user.
                    Toast.makeText(WebBrowserScreen.this, "Permission is Required for getting list of files", Toast.LENGTH_SHORT).show();

    public boolean onKeyDown(int keyCode, KeyEvent event) {
        // Check if the key event was the Back button and if there's history
        if ((keyCode == KeyEvent.KEYCODE_BACK) && webView.canGoBack()) {
            return true;
        // If it wasn't the Back key or there's no web page history, bubble up to the default
        // system behavior (probably exit the activity)

        return super.onKeyDown(keyCode, event);

    public class PQClient extends WebViewClient {
        ProgressBar progressDialog;

        public boolean shouldOverrideUrlLoading(WebView view, String url) {

            // If url contains mailto link then open Mail Intent
            if (url.contains("mailto:")) {

                // Could be cleverer and use a regex
                //Open links in new browser
                        new Intent(Intent.ACTION_VIEW, Uri.parse(url)));

                // Here we can open new activity

                return true;

            } else {
                // Stay within this webview and load url
                return true;

        // Show loader on url load
        public void onPageStarted(WebView view, String url, Bitmap favicon) {
            // Then show progress  Dialog
            // in standard case YourActivity.this
            if (progressDialog == null) {
                progressDialog = findViewById(;

        // Called when all page resources loaded
        public void onPageFinished(WebView view, String url) {
            webView.loadUrl("javascript:(function(){ " +

            try {
                // Close progressDialog
            } catch (Exception exception) {


What is the official "preferred" way to install pip and virtualenv systemwide?

There really isn't a single "answer" to this question, but there are definitely some helpful concepts that can help you to come to a decision.

The first question that needs to be answered in your use case is "Do I want to use the system Python?" If you want to use the Python distributed with your operating system, then using the apt-get install method may be just fine. Depending on the operating system distribution method though, you still have to ask some more questions, such as "Do I want to install multiple versions of this package?" If the answer is yes, then it is probably not a good idea to use something like apt. Dpkg pretty much will just untar an archive at the root of the filesystem, so it is up to the package maintainer to make sure the package installs safely under very little assumptions. In the case of most debian packages, I would assume (someone can feel free to correct me here) that they simply untar and provide a top level package.

For example, say the package is "virtualenv", you'd end up with /usr/lib/python2.x/site-packages/virtualenv. If you install it with easy_install you'd get something like /usr/lib/python2.x/site-packages/virtualenv.egg-link that might point to /usr/lib/python2.x/site-packages/virtualenv-1.2-2.x.egg which may be a directory or zipped egg. Pip does something similar although it doesn't use eggs and instead will place the top level package directly in the lib directory.

I might be off on the paths, but the point is that each method takes into account different needs. This is why tools like virtualenv are helpful as they allow you to sandbox your Python libraries such that you can have any combination you need of libraries and versions.

Setuptools also allows installing packages as multiversion which means there is not a singular module_name.egg-link created. To import those packages you need to use pkg_resources and the __import__ function.

Going back to your original question, if you are happy with the system python and plan on using virtualenv and pip to build environments for different applications, then installing virtualenv and / or pip at the system level using apt-get seems totally appropriate. One word of caution though is that if you plan on upgrading your distributions Python, that may have a ripple effect through your virtualenvs if you linked back to your system site packages.

I should also mention that none of these options is inherently better than the others. They simply take different approaches. Using the system version is an excellent way to install Python applications, yet it can be a very difficult way to develop with Python. Easy install and setuptools is very convenient in a world without virtualenv, but if you need to use different versions of the same library, then it also become rather unwieldy. Pip and virtualenv really act more like a virtual machine. Instead of taking care to install things side by side, you just create an whole new environment. The downside here is that 30+ virtualenvs later you might have used up quite bit of diskspace and cluttered up your filesystem.

As you can see, with the many options it is difficult to say which method to use, but with a little investigation into your use cases, you should be able to find a method that works.

Output array to CSV in Ruby

Building on @boulder_ruby's answer, this is what I'm looking for, assuming us_eco contains the CSV table as from my gist.'outfile.txt','wb', col_sep: "\t") do |csvfile|
  csvfile << us_eco.first.keys
  us_eco.each do |row|
    csvfile << row.values

Updated the gist at

SQL Server - stop or break execution of a SQL script

I would suggest that you wrap your appropriate code block in a try catch block. You can then use the Raiserror event with a severity of 11 in order to break to the catch block if you wish. If you just want to raiserrors but continue execution within the try block then use a lower severity.

Make sense?

Cheers, John

[Edited to include BOL Reference]

Images can't contain alpha channels or transparencies

i was able to use imageoptim to remove alpha channel and compress png files.

Adding extra zeros in front of a number using jQuery?

var str = "43215"; 
console.log("Before : \n string :"+str+"\n Length :"+str.length);
var max = 9;
while(str.length < max ){
                                str = "0" + str;

console.log("After : \n string :"+str+"\n Length :"+str.length);

It worked for me ! To increase the zeroes, update the 'max' variable

Working Fiddle URL : Adding extra zeros in front of a number using jQuery?:

HTML checkbox onclick called in Javascript

Label without an onclick will behave as you would expect. It changes the input. What you relly want is to execute selectAll() when you click on a label, right? Then only add select all to the label onclick. Or wrap the input into the the label and assign onclick only for the label

<label for="check_all_1" onclick="selectAll(document.wizard_form, this);">
  <input type="checkbox" id="check_all_1" name="check_all_1" title="Select All">
  Select All

Eclipse - Installing a new JRE (Java SE 8 1.8.0)

You can have many java versions in your system.

I think you should add the java 8 in yours JREs installed or edit.

Take a look my screen:

enter image description here

If you click in edit (check your java 8 path):

enter image description here

Handling Enter Key in Vue.js

Event Modifiers

You can refer to event modifiers in vuejs to prevent form submission on enter key.

It is a very common need to call event.preventDefault() or event.stopPropagation() inside event handlers.

Although we can do this easily inside methods, it would be better if the methods can be purely about data logic rather than having to deal with DOM event details.

To address this problem, Vue provides event modifiers for v-on. Recall that modifiers are directive postfixes denoted by a dot.

<form v-on:submit.prevent="<method>">

As the documentation states, this is syntactical sugar for e.preventDefault() and will stop the unwanted form submission on press of enter key.

Here is a working fiddle.

new Vue({_x000D_
  el: '#myApp',_x000D_
  data: {_x000D_
    emailAddress: '',_x000D_
    log: ''_x000D_
  methods: {_x000D_
    validateEmailAddress: function(e) {_x000D_
      if (e.keyCode === 13) {_x000D_
        alert('Enter was pressed');_x000D_
      } else if (e.keyCode === 50) {_x000D_
        alert('@ was pressed');_x000D_
      }      _x000D_
      this.log += e.key;_x000D_
    postEmailAddress: function() {_x000D_
   this.log += '\n\nPosting';_x000D_
    noop () {_x000D_
      // do nothing ?_x000D_
html, body, #editor {_x000D_
  margin: 0;_x000D_
  height: 100%;_x000D_
  color: #333;_x000D_
<script src="[email protected]/dist/vue.js"></script>_x000D_
<div id="myApp" style="padding:2rem; background-color:#fff;">_x000D_
<form v-on:submit.prevent="noop">_x000D_
  <input type="text" v-model="emailAddress" v-on:keyup="validateEmailAddress" />_x000D_
  <button type="button" v-on:click="postEmailAddress" >Subscribe</button> _x000D_
  <br /><br />_x000D_
  <textarea v-model="log" rows="4"></textarea>  _x000D_

SQL UPDATE all values in a field with appended string CONCAT not working

CONCAT with a null value returns null, so the easiest solution is:

UPDATE myTable SET spares = IFNULL (CONCAT( spares , "string" ), "string")

What encoding/code page is cmd.exe using?

To answer your second query re. how encoding works, Joel Spolsky wrote a great introductory article on this. Strongly recommended.

"Could not find or load main class" Error while running java program using cmd prompt

I faced the same problem and tried everything mentioned here. The thing was I didn't refresh my project in eclipse after class creation . And once I refreshed it things worked as expected.

How do I get an empty array of any size in python?

Just declare the list and append each element. For ex:

a = []
a.append('first item')
a.append('second item')

Responsive dropdown navbar with angular-ui bootstrap (done in the correct angular kind of way)

Not sure if anyone is having the same responsive issue, but it was just a simple css solution for me.

same example

...  ng-init="isCollapsed = true" ng-click="isCollapsed = !isCollapsed"> ...
...  div collapse="isCollapsed"> ...


@media screen and (min-width: 768px) {
        display: block !important;

document.getElementByID is not a function

It worked like this for me:

document.getElementById("theElementID").setAttribute("src", source);
document.getElementById("task-text").innerHTML = "";

Change the


for your element locator (name, css, xpath...)

How do I create directory if it doesn't exist to create a file?

var filePath = context.Server.MapPath(Convert.ToString(ConfigurationManager.AppSettings["ErrorLogFile"]));

var file = new FileInfo(filePath);

file.Directory.Create(); If the directory already exists, this method does nothing.

var sw = new StreamWriter(filePath, true);

sw.WriteLine(Enter your message here);


php execute a background process

I am heavily using fast_cgi_finish_request()

In combination with a closure and register_shutdown_function()

$message ='job executed';
$backgroundJob = function() use ($message) {
     //do some work here
    echo $message;

Then register this closure to be executed before shutdown.


Finally when the response was sent to the client you can close the connection to the client and continue working with the PHP process:


The closure will be executed after fast_cgi_finish_request.

The $message will not be visible at any time. And you can register as much closures as you want, but take care about script execution time. This will only work if PHP is running as a Fast CGI module (was that right?!)

equivalent of rm and mv in windows .cmd

If you want to see a more detailed discussion of differences for the commands, see the Details about Differences section, below.

From the website1 (archived), specifically the Windows and Unix command line equivalents page (archived), I found the following2. There's a better/more complete table in the next edit.

Windows command     Unix command
rmdir               rmdir
rmdir /s            rm -r
move                mv

I'm interested to hear from @Dave and @javadba to hear how equivalent the commands are - how the "behavior and capabilities" compare, whether quite similar or "woefully NOT equivalent".

All I found out was that when I used it to try and recursively remove a directory and its constituent files and subdirectories, e.g.

(Windows cmd)>rmdir /s C:\my\dirwithsubdirs\

gave me a standard Windows-knows-better-than-you-do-are-you-sure message and prompt

dirwithsubdirs, Are you sure (Y/N)?

and that when I typed Y, the result was that my top directory and its constituent files and subdirectories went away.


I'm looking back at this after finding this answer. I retried each of the commands, and I'd change the table a little bit.

Windows command     Unix command
rmdir               rmdir
rmdir /s /q         rm -r
rmdir /s /q         rm -rf
rmdir /s            rm -ri
move                mv
del <file>          rm <file>

If you want the equivalent for

rm -rf

you can use

rmdir /s /q

or, as the author of the answer I sourced described,

But there is another "old school" way to do it that was used back in the day when commands did not have options to suppress confirmation messages. Simply ECHO the needed response and pipe the value into the command.

echo y | rmdir /s

Details about Differences

I tested each of the commands using Windows CMD and Cygwin (with its bash).

Before each test, I made the following setup.

Windows CMD

>mkdir this_directory
>echo some text stuff > this_directory/some.txt
>mkdir this_empty_directory

Cygwin bash

$ mkdir this_directory
$ echo "some text stuff" > this_directory/some.txt
$ mkdir this_empty_directory

That resulted in the following file structure for both.

|-- this_directory
|   `-- some.txt
`-- this_empty_directory

Here are the results. Note that I'll not mark each as CMD or bash; the CMD will have a > in front, and the bash will have a $ in front.


>rmdir this_directory
The directory is not empty.

>tree /a /f .
Folder PATH listing for volume Windows
Volume serial number is ¦¦¦¦¦¦¦¦ ¦¦¦¦:¦¦¦¦
|       some.txt

> rmdir this_empty_directory

>tree /a /f .
$ rmdir this_directory
rmdir: failed to remove 'this_directory': Directory not empty

$ tree --charset=ascii
|-- this_directory
|   `-- some.txt
`-- this_empty_directory

2 directories, 1 file

$ rmdir this_empty_directory

$ tree --charset=ascii
`-- this_directory
    `-- some.txt

RMDIR /S /Q and RM -R ; RM -RF

>rmdir /s /q this_directory

>tree /a /f

>rmdir /s /q this_empty_directory

>tree /a /f
No subfolders exist
$ rm -r this_directory

$ tree --charset=ascii
`-- this_empty_directory

$ rm -r this_empty_directory

$ tree --charset=ascii
0 directories, 0 files
$ rm -rf this_directory

$ tree --charset=ascii
`-- this_empty_directory

$ rm -rf this_empty_directory

$ tree --charset=ascii
0 directories, 0 files

RMDIR /S AND RM -RI Here, we have a bit of a difference, but they're pretty close.

>rmdir /s this_directory
this_directory, Are you sure (Y/N)? y

>tree /a /f

>rmdir /s this_empty_directory
this_empty_directory, Are you sure (Y/N)? y

>tree /a /f
No subfolders exist
$ rm -ri this_directory
rm: descend into directory 'this_directory'? y
rm: remove regular file 'this_directory/some.txt'? y
rm: remove directory 'this_directory'? y

$ tree --charset=ascii
`-- this_empty_directory

$ rm -ri this_empty_directory
rm: remove directory 'this_empty_directory'? y

$ tree --charset=ascii
0 directories, 0 files



  1. I know almost nothing about the LeMoDa website, other than the fact that the info is

Copyright © Ben Bullock 2009-2018. All rights reserved.

(archived copyright notice)

and that there seem to be a bunch of useful programming tips along with some humour (yes, the British spelling) and information on how to fix Japanese toilets. I also found some stuff talking about the "Ibaraki Report", but I don't know if that is the website.

I think I shall go there more often; it's quite useful. Props to Ben Bullock, whose email is on his page. If he wants me to remove this info, I will.

I will include the disclaimer (archived) from the site:

Disclaimer Please read the following disclaimer before using any of the computer program code on this site.

There Is No Warranty For The Program, To The Extent Permitted By Applicable Law. Except When Otherwise Stated In Writing The Copyright Holders And/Or Other Parties Provide The Program “As Is” Without Warranty Of Any Kind, Either Expressed Or Implied, Including, But Not Limited To, The Implied Warranties Of Merchantability And Fitness For A Particular Purpose. The Entire Risk As To The Quality And Performance Of The Program Is With You. Should The Program Prove Defective, You Assume The Cost Of All Necessary Servicing, Repair Or Correction.

In No Event Unless Required By Applicable Law Or Agreed To In Writing Will Any Copyright Holder, Or Any Other Party Who Modifies And/Or Conveys The Program As Permitted Above, Be Liable To You For Damages, Including Any General, Special, Incidental Or Consequential Damages Arising Out Of The Use Or Inability To Use The Program (Including But Not Limited To Loss Of Data Or Data Being Rendered Inaccurate Or Losses Sustained By You Or Third Parties Or A Failure Of The Program To Operate With Any Other Programs), Even If Such Holder Or Other Party Has Been Advised Of The Possibility Of Such Damages.

  1. Actually, I found the information with a Google search for "cmd equivalent of rm"

The information I'm sharing came up first.

How can jQuery deferred be used?

The best use case I can think of is in caching AJAX responses. Here's a modified example from Rebecca Murphey's intro post on the topic:

var cache = {};

function getData( val ){

    // return either the cached value or jqXHR object wrapped Promise
    return $.when(
        cache[ val ] || 
        $.ajax('/foo/', {
            data: { value: val },
            dataType: 'json',
            success: function( resp ){
                cache[ val ] = resp;

    // do something with the response, which may
    // or may not have been retrieved using an
    // XHR request.

Basically, if the value has already been requested once before it's returned immediately from the cache. Otherwise, an AJAX request fetches the data and adds it to the cache. The $.when/.then doesn't care about any of this; all you need to be concerned about is using the response, which is passed to the .then() handler in both cases. jQuery.when() handles a non-Promise/Deferred as a Completed one, immediately executing any .done() or .then() on the chain.

Deferreds are perfect for when the task may or may not operate asynchronously, and you want to abstract that condition out of the code.

Another real world example using the $.when helper:

$.when($.getJSON('/some/data/'), $.get('template.tpl')).then(function (data, tmpl) {

    $(tmpl) // create a jQuery object out of the template
    .tmpl(data) // compile it
    .appendTo("#target"); // insert it into the DOM


Convert base-2 binary number string to int

You use the built-in int function, and pass it the base of the input number, i.e. 2 for a binary number:

>>> int('11111111', 2)

Here is documentation for python2, and for python3.

Adding timestamp to a filename with mv in BASH

The few lines you posted from your script look okay to me. It's probably something a bit deeper.

You need to find which line is giving you this error. Add set -xv to the top of your script. This will print out the line number and the command that's being executed to STDERR. This will help you identify where in your script you're getting this particular error.

BTW, do you have a shebang at the top of your script? When I see something like this, I normally expect its an issue with the Shebang. For example, if you had #! /bin/bash on top, but your bash interpreter is located in /usr/bin/bash, you'll see this error.


New question: How can I save the file correctly in the first place, to avoid having to perform this fix every time I resend the file?

Two ways:

  1. Select the Edit->EOL Conversion->Unix Format menu item when you edit a file. Once it has the correct line endings, Notepad++ will keep them.
  2. To make sure all new files have the correct line endings, go to the Settings->Preferences menu item, and pull up the Preferences dialog box. Select the New Document/Default Directory tab. Under New Document and Format, select the Unix radio button. Click the Close button.

Passing in class names to react components

For anyone interested, I ran into this same issue when using css modules and react css modules.

Most components have an associated css module style, and in this example my Button has its own css file, as does the Promo parent component. But I want to pass some additional styles to Button from Promo

So the styleable Button looks like this:


import React, { Component } from 'react'
import CSSModules from 'react-css-modules'
import styles from './Button.css'

class Button extends Component {

  render() {

    let button = null,
        className = ''

    if(this.props.className !== undefined){
        className = this.props.className

    button = (
      <button className={className} styleName='button'>

    return (

export default CSSModules(Button, styles, {allowMultiple: true} )

In the above Button component the Button.css styles handle the common button styles. In this example just a .button class

Then in my component where I want to use the Button, and I also want to modify things like the position of the button, I can set extra styles in Promo.css and pass through as the className prop. In this example again called .button class. I could have called it anything e.g. promoButton.

Of course with css modules this class will be .Promo__button___2MVMD whereas the button one will be something like .Button__button___3972N


import React, { Component } from 'react';
import CSSModules from 'react-css-modules';
import styles from './Promo.css';

import Button from './Button/Button'

class Promo extends Component {

  render() {

    return (
        <div styleName='promo' >
          <h1>Testing the button</h1>
          <Button className={styles.button} >
            <span>Hello button</span>

export default CSSModules(Promo, styles, {allowMultiple: true} ); Validation of viewstate MAC failed

This solution worked for me in ASP.NET 4.5 using a Web Forms site.

  1. Use the following site to generate a Machine Key:
  2. Copy Full Machine Key Code.
  3. Go To your Web.Config File.
  4. Paste the Machine Key in the following code section:
        <machineKey ... />

You should not see the viewstate Mac failed error anymore. Each website in the same app pool should have a separate machine key otherwise this error will continue.

':app:lintVitalRelease' error when generating signed apk

I have faced same issue when creating signed apk from android studio. I just change little bit change on build.gradle file inside android {}

lintOptions {
        checkReleaseBuilds false
        abortOnError false

SQL Error: ORA-00933: SQL command not properly ended

Your query should look like

UPDATE table_name
SET column1=value, column2=value2,...
WHERE some_column=some_value

You can check the below question for help

Specified cast is not valid?

Try this:

public void LoadData()
            SqlConnection con = new SqlConnection("Data Source=.;Initial Catalog=Stocks;Integrated Security=True;Pooling=False");
            SqlDataAdapter sda = new SqlDataAdapter("Select * From [Stocks].[dbo].[product]", con);
            DataTable dt = new DataTable();

        foreach (DataRow item in dt.Rows)
            int n = DataGridView1.Rows.Add();
            DataGridView1.Rows[n].Cells[0].Value = item["ProductCode"].ToString();
            DataGridView1.Rows[n].Cells[1].Value = item["Productname"].ToString();
            DataGridView1.Rows[n].Cells[2].Value = item["qty"].ToString();                
            if ((bool)item["productstatus"])
                DataGridView1.Rows[n].Cells[3].Value = "Active";
                DataGridView1.Rows[n].Cells[3].Value = "Deactive";

How do you import an Eclipse project into Android Studio now?

According to, You have a couple of choices
- simply importing
- pre-exporting first from Eclipse.

Pre-exporting from eclipse may be the better choice if your project contains a lot of relationships that are Eclipse-specific. A.S. cannot 'translate' everything Eclipse can produce. If you want to continue using Eclipse as well as A.S. on this project code, this is the better choice. If you choose this method, please read the above link, there are some important pre-requisites.

Simply importing into AS will let AS 'translate' and rearrange the project, and is the recommended method, especially if you have no intention of returning to Eclipse. In this case, you let the A.S. wizard do everything and you dont need to manually generate gradle files.

How to check command line parameter in ".bat" file?

Look at for an answer; the command is IF [%1]==[] GOTO NO_ARGUMENT or similar.

Can I change the fill color of an svg path with CSS?

You can use this syntax but it will require some changes in the SVG file. And remove any fill/stroke from the SVG itself.


<svg xmlns="" xmlns:xlink="" version="1.1">
<!-- use symbol instead of defs and g, 
  must add viewBox on symbol just copy yhe viewbox from the svg tag itself
  must add id on symbol
<symbol id="location" viewBox="0 0 430.114 430.114">
  <!-- add all the icon's paths and shapes here -->
  <path d="M356.208,107.051c-1.531-5.738-4.64-11.852-6.94-17.205C321.746,23.704,261.611,0,213.055,0   C148.054,0,76.463,43.586,66.905,133.427v18.355c0,0.766,0.264,7.647,0.639,11.089c5.358,42.816,39.143,88.32,64.375,131.136   c27.146,45.873,55.314,90.999,83.221,136.106c17.208-29.436,34.354-59.259,51.17-87.933c4.583-8.415,9.903-16.825,14.491-24.857   c3.058-5.348,8.9-10.696,11.569-15.672c27.145-49.699,70.838-99.782,70.838-149.104v-20.262   C363.209,126.938,356.581,108.204,356.208,107.051z M214.245,199.193c-19.107,0-40.021-9.554-50.344-35.939   c-1.538-4.2-1.414-12.617-1.414-13.388v-11.852c0-33.636,28.56-48.932,53.406-48.932c30.588,0,54.245,24.472,54.245,55.06   C270.138,174.729,244.833,199.193,214.245,199.193z"/>


<svg><use xlink:href="file_path/location.svg#location"></use></svg>

How to place a div on the right side with absolute position

I'm assuming that your container element is probably position:relative;. This is will mean that the dialog box will be positioned accordingly to the container, not the page.

Can you change the markup to this?

    <!-- Need to place this div at the top right of the page-->
        <div class="ajax-message">
            <div class="row">
                <div class="span9">
                    <div class="alert">
                        <a class="close icon icon-remove"></a>
                        <div class="message-content">
                            Some message goes here
    <div class="container">
        <!-- Page contents starts here. These are dynamic-->
        <div class="row">
            <div class="span12 inner-col">

With the dialog box outside the main container then you can use absolute positioning relative to the page.

Android: show/hide a view using an animation




        android:text="message_error_authentication" />

        android:text="message_error_authentication_connection" />

        android:text="message_error_authentication_field_empty" />



public void show(int viewId) {
    ViewAnimator animator = (ViewAnimator) findView(animatorId);
    View view = findViewById(viewId);

    if (animator.getDisplayedChild() != animator.indexOfChild(view)) {

 private void showAuthenticationConnectionFailureMessage() {

Is it possible to create a remote repo on GitHub from the CLI without opening browser?

CLI commands for github API v3 (replace all CAPS keywords):

curl -u 'USER' -d '{"name":"REPO"}'
# Remember replace USER with your username and REPO with your repository/application name!
git remote add origin [email protected]:USER/REPO.git
git push origin master

How to use OpenSSL to encrypt/decrypt files?

Update using a random generated public key.


openssl enc -aes-256-cbc -a -salt -in {raw data} -out {encrypted data} -pass file:{random key}


openssl enc -d -aes-256-cbc -in {ciphered data} -out {raw data}

Merging a lot of data.frames

Put them into a list and use merge with Reduce

Reduce(function(x, y) merge(x, y, all=TRUE), list(df1, df2, df3))
#    id v1 v2 v3
# 1   1  1 NA NA
# 2  10  4 NA NA
# 3   2  3  4 NA
# 4  43  5 NA NA
# 5  73  2 NA NA
# 6  23 NA  2  1
# 7  57 NA  3 NA
# 8  62 NA  5  2
# 9   7 NA  1 NA
# 10 96 NA  6 NA

You can also use this more concise version:

Reduce(function(...) merge(..., all=TRUE), list(df1, df2, df3))

What is the difference between require() and library()?

My initial theory about the difference was that library loads the packages whether it is already loaded or not, i.e. it might reload an already loaded package, while require just checks that it is loaded, or loads it if it isn't (thus the use in functions that rely on a certain package). The documentation refutes this, however, and explicitly states that neither function will reload an already loaded package.

ReactJS - .JS vs .JSX

Besides the mentioned fact that JSX tags are not standard javascript, the reason I use .jsx extension is because with it Emmet still works in the editor - you know, that useful plugin that expands html code, for example ul>li into


Numpy - add row to array

import numpy as np
array_ = np.array([[1,2,3]])
add_row = np.array([[4,5,6]])

array_ = np.concatenate((array_, add_row), axis=0)

Cannot read property 'style' of undefined -- Uncaught Type Error

It's currently working, I've just changed the operator > in order to work in the snippet, take a look:

window.onload = function() {_x000D_
  if (window.location.href.indexOf("test") <= -1) {_x000D_
    var search_span = document.getElementsByClassName("securitySearchQuery");_x000D_
    search_span[0].style.color = "blue";_x000D_
    search_span[0].style.fontWeight = "bold";_x000D_
    search_span[0].style.fontSize = "40px";_x000D_
<h1 class="keyword-title">Search results for<span class="securitySearchQuery"> "hi".</span></h1>

How can I change an element's class with JavaScript?

Here's a toggleClass to toggle/add/remove a class on an element:

// If newState is provided add/remove theClass accordingly, otherwise toggle theClass
function toggleClass(elem, theClass, newState) {
    var matchRegExp = new RegExp('(?:^|\\s)' + theClass + '(?!\\S)', 'g');
    var add=(arguments.length>2 ? newState : (elem.className.match(matchRegExp) == null));

    elem.className=elem.className.replace(matchRegExp, ''); // clear all
    if (add) elem.className += ' ' + theClass;

see jsfiddle

also see my answer here for creating a new class dynamically

OpenSSL Verify return code: 20 (unable to get local issuer certificate)

this error messages means that CABundle is not given by (-CAfile ...) OR the CABundle file is not closed by a self-signed root certificate.

Don't worry. The connection to server will work even you get theis message from openssl s_client ... (assumed you dont take other mistake too)

Simple 3x3 matrix inverse code (C++)

# include <conio.h>
# include<iostream.h>

const int size = 9;

int main()
    char ch;

        int i, j, x, y, z, det, a[size], b[size];

        cout << "           **** MATRIX OF 3x3 ORDER ****"
             << endl
             << endl
             << endl;

        for (i = 0; i <= size; i++)

        for (i = 0; i < size; i++)
            cout << "Enter "
                 << i + 1
                 << " element of matrix=";

            cin >> a[i]; 

            cout << endl


        cout << "your entered matrix is "
             << endl

        for (i = 0; i < size; i += 3)
            cout << a[i]
                 << "  "
                 << a[i+1]
                 << "  "
                 << a[i+2]
                 << endl

        cout << "Transpose of given matrix is"
             << endl
             << endl;

        for (i = 0; i < 3; i++)
            cout << a[i]
                 << "  "
                 << a[i+3]
                 << "  "
                 << a[i+6]
                 << endl
                 << endl;

        cout << "Determinent of given matrix is = ";

        x = a[0] * (a[4] * a[8] -a [5] * a[7]);
        y = a[1] * (a[3] * a[8] -a [5] * a[6]);
        z = a[2] * (a[3] * a[7] -a [4] * a[6]);
        det = x - y + z;

        cout << det 
             << endl
             << endl
             << endl
             << endl;

        if (det == 0)
            cout << "As Determinent=0 so it is singular matrix and its inverse cannot exist"
                 << endl
                 << endl;

            goto quit;

        b[0] = a[4] * a[8] - a[5] * a[7];
        b[1] = a[5] * a[6] - a[3] * a[8];
        b[2] = a[3] * a[7] - a[4] * a[6];
        b[3] = a[2] * a[7] - a[1] * a[8];
        b[4] = a[0] * a[8] - a[2] * a[6];
        b[5] = a[1] * a[6] - a[0] * a[7];
        b[6] = a[1] * a[5] - a[2] * a[4];
        b[7] = a[2] * a[3] - a[0] * a[5];
        b[8] = a[0] * a[4] - a[1] * a[3];

        cout << "Adjoint of given matrix is"
             << endl
             << endl;

        for (i = 0; i < 3; i++)
            cout << b[i]
                 << "  "
                 << b[i+3]
                 << "  "
                 << b[i+6]
                 << endl

        cout << endl

        cout << "Inverse of given matrix is "
             << endl
             << endl
             << endl;

        for (i = 0; i < 3; i++)
            cout << b[i]
                 << "/"
                 << det
                 << "  "
                 << b[i+3]
                 << "/" 
                 << det
                 << "  "
                 << b[i+6]
                 << "/" 
                 << det
                 << endl


        cout << endl
             << endl;

        cout << "Do You want to continue this again press (y/yes,n/no)";

        cin >> ch; 

        cout << endl
             << endl;
    } /* end do */

    while (ch == 'y');
    getch ();

    return 0;

font awesome icon in select option

You can't add i tag in option tag because tags are stripped.

But you can add it after the select like this

If you can decode JWT, how are they secure?

Let's discuss from the very beginning:

JWT is a very modern, simple and secure approach which extends for Json Web Tokens. Json Web Tokens are a stateless solution for authentication. So there is no need to store any session state on the server, which of course is perfect for restful APIs. Restful APIs should always be stateless, and the most widely used alternative to authentication with JWTs is to just store the user's log-in state on the server using sessions. But then of course does not follow the principle that says that restful APIs should be stateless and that's why solutions like JWT became popular and effective.

So now let's know how authentication actually works with Json Web Tokens. Assuming we already have a registered user in our database. So the user's client starts by making a post request with the username and the password, the application then checks if the user exists and if the password is correct, then the application will generate a unique Json Web Token for only that user.

The token is created using a secret string that is stored on a server. Next, the server then sends that JWT back to the client which will store it either in a cookie or in local storage. enter image description here

Just like this, the user is authenticated and basically logged into our application without leaving any state on the server.

So the server does in fact not know which user is actually logged in, but of course, the user knows that he's logged in because he has a valid Json Web Token which is a bit like a passport to access protected parts of the application.

So again, just to make sure you got the idea. A user is logged in as soon as he gets back his unique valid Json Web Token which is not saved anywhere on the server. And so this process is therefore completely stateless.

Then, each time a user wants to access a protected route like his user profile data, for example. He sends his Json Web Token along with a request, so it's a bit like showing his passport to get access to that route.

Once the request hits the server, our app will then verify if the Json Web Token is actually valid and if the user is really who he says he is, well then the requested data will be sent to the client and if not, then there will be an error telling the user that he's not allowed to access that resource. enter image description here

All this communication must happen over https, so secure encrypted Http in order to prevent that anyone can get access to passwords or Json Web Tokens. Only then we have a really secure system.

enter image description here

So a Json Web Token looks like left part of this screenshot which was taken from the JWT debugger at So essentially, it's an encoding string made up of three parts. The header, the payload and the signature Now the header is just some metadata about the token itself and the payload is the data that we can encode into the token, any data really that we want. So the more data we want to encode here the bigger the JWT. Anyway, these two parts are just plain text that will get encoded, but not encrypted.

So anyone will be able to decode them and to read them, we cannot store any sensitive data in here. But that's not a problem at all because in the third part, so in the signature, is where things really get interesting. The signature is created using the header, the payload, and the secret that is saved on the server.

And this whole process is then called signing the Json Web Token. The signing algorithm takes the header, the payload, and the secret to create a unique signature. So only this data plus the secret can create this signature, all right? Then together with the header and the payload, these signature forms the JWT, which then gets sent to the client. enter image description here

Once the server receives a JWT to grant access to a protected route, it needs to verify it in order to determine if the user really is who he claims to be. In other words, it will verify if no one changed the header and the payload data of the token. So again, this verification step will check if no third party actually altered either the header or the payload of the Json Web Token.

So, how does this verification actually work? Well, it is actually quite straightforward. Once the JWT is received, the verification will take its header and payload, and together with the secret that is still saved on the server, basically create a test signature.

But the original signature that was generated when the JWT was first created is still in the token, right? And that's the key to this verification. Because now all we have to do is to compare the test signature with the original signature. And if the test signature is the same as the original signature, then it means that the payload and the header have not been modified. enter image description here

Because if they had been modified, then the test signature would have to be different. Therefore in this case where there has been no alteration of the data, we can then authenticate the user. And of course, if the two signatures are actually different, well, then it means that someone tampered with the data. Usually by trying to change the payload. But that third party manipulating the payload does of course not have access to the secret, so they cannot sign the JWT. So the original signature will never correspond to the manipulated data. And therefore, the verification will always fail in this case. And that's the key to making this whole system work. It's the magic that makes JWT so simple, but also extremely powerful.

How to solve ' a 'type', which is not valid in the given context'? (C#)

CERAS is a class name which cannot be assigned. As the class implements IDisposable a typical usage would be:

using (CERas.CERAS ceras = new CERas.CERAS())
    // call some method on ceras

phantomjs not waiting for "full" page load

You could try a combination of the waitfor and rasterize examples:

 * See
 * Wait until the test condition is true or a timeout occurs. Useful for waiting
 * on a server response or for a ui change (fadeIn, etc.) to occur.
 * @param testFx javascript condition that evaluates to a boolean,
 * it can be passed in as a string (e.g.: "1 == 1" or "$('#bar').is(':visible')" or
 * as a callback function.
 * @param onReady what to do when testFx condition is fulfilled,
 * it can be passed in as a string (e.g.: "1 == 1" or "$('#bar').is(':visible')" or
 * as a callback function.
 * @param timeOutMillis the max amount of time to wait. If not specified, 3 sec is used.
function waitFor(testFx, onReady, timeOutMillis) {
    var maxtimeOutMillis = timeOutMillis ? timeOutMillis : 3000, //< Default Max Timout is 3s
        start = new Date().getTime(),
        condition = (typeof(testFx) === "string" ? eval(testFx) : testFx()), //< defensive code
        interval = setInterval(function() {
            if ( (new Date().getTime() - start < maxtimeOutMillis) && !condition ) {
                // If not time-out yet and condition not yet fulfilled
                condition = (typeof(testFx) === "string" ? eval(testFx) : testFx()); //< defensive code
            } else {
                if(!condition) {
                    // If condition still not fulfilled (timeout but condition is 'false')
                    console.log("'waitFor()' timeout");
                } else {
                    // Condition fulfilled (timeout and/or condition is 'true')
                    console.log("'waitFor()' finished in " + (new Date().getTime() - start) + "ms.");
                    typeof(onReady) === "string" ? eval(onReady) : onReady(); //< Do what it's supposed to do once the condition is fulfilled
                    clearInterval(interval); //< Stop this interval
        }, 250); //< repeat check every 250ms

var page = require('webpage').create(), system = require('system'), address, output, size;

if (system.args.length < 3 || system.args.length > 5) {
    console.log('Usage: rasterize.js URL filename [paperwidth*paperheight|paperformat] [zoom]');
    console.log('  paper (pdf output) examples: "5in*7.5in", "10cm*20cm", "A4", "Letter"');
} else {
    address = system.args[1];
    output = system.args[2];
    if (system.args.length > 3 && system.args[2].substr(-4) === ".pdf") {
        size = system.args[3].split('*');
        page.paperSize = size.length === 2 ? {
            width : size[0],
            height : size[1],
            margin : '0px'
        } : {
            format : system.args[3],
            orientation : 'portrait',
            margin : {
                left : "5mm",
                top : "8mm",
                right : "5mm",
                bottom : "9mm"
    if (system.args.length > 4) {
        page.zoomFactor = system.args[4];
    var resources = [];
    page.onResourceRequested = function(request) {
        resources[] = request.stage;
    page.onResourceReceived = function(response) {
        resources[] = response.stage;
    };, function(status) {
        if (status !== 'success') {
            console.log('Unable to load the address!');
        } else {
            waitFor(function() {
                // Check in the page if a specific element is now visible
                for ( var i = 1; i < resources.length; ++i) {
                    if (resources[i] != 'end') {
                        return false;
                return true;
            }, function() {
            }, 10000);

Show "loading" animation on button click

        beforeSend : function(xhr, opts){
            //show loading gif
        success: function(){

        complete : function() {
           //remove loading gif

Android emulator: could not get wglGetExtensionsStringARB error

i had a same issue because of my Nvidea Graphics card Driver Problem.

If your System has Dedicated Graphics card then Check for the latest Driver and Install it.

Other wise simply Choose Emulated Performance as Software in Emulator Configurations enter image description here

After Updating the driver the issue is resolved :)

How to change JAVA.HOME for Eclipse/ANT

Under Windows you need to follow:

Start -> Control Panel -> System -> Advanced -> Environment Variables.

... and you need to set JAVA_HOME (which is distinct from the PATH variable you mention) to reference the JDK home directory, not the bin sub-directory; e.g. "C:\program files\java\jdk".

Increasing Google Chrome's max-connections-per-server limit to more than 6

I don't know that you can do it in Chrome outside of Windows -- some Googling shows that Chrome (and therefore possibly Chromium) might respond well to a certain registry hack.

However, if you're just looking for a simple solution without modifying your code base, have you considered Firefox? In the about:config you can search for "network.http.max" and there are a few values in there that are definitely worth looking at.

Also, for a device that will not be moving (i.e. it is mounted in a fixed location) you should consider not using Wi-Fi (even a Home-Plug would be a step up as far as latency / stability / dropped connections go).

C# How can I check if a URL exists/is valid?

If I understand your question correctly, you could use a small method like this to give you the results of your URL test:

WebRequest webRequest = WebRequest.Create(url);  
WebResponse webResponse;
  webResponse = webRequest.GetResponse();
catch //If exception thrown then couldn't get response from address
  return 0;
return 1;

You could wrap the above code in a method and use it to perform validation. I hope this answers the question you were asking.

Function stoi not declared

In comments under another answer, you indicated you are using a dodgy version of g++ under MS Windows.

In this case, -std=c++11 as suggested by the top answer would still not fix the problem.

Please see the following thread which does discuss your situation: std::stoi doesn't exist in g++ 4.6.1 on MinGW

Reading rows from a CSV file in Python

I just leave my solution here.

import csv
import numpy as np

with open(name, newline='') as f:
    reader = csv.reader(f, delimiter=",")
    # skip header
    # convert csv to list and then to np.array
    data  = np.array(list(reader))[:, 1:] # skip the first column

print(data.shape) # => (N, 2)

# sum each row
s = data.sum(axis=1)
print(s.shape) # => (N,)

What's the console.log() of java?

Use the Android logging utility.

Log has a bunch of static methods for accessing the different log levels. The common thread is that they always accept at least a tag and a log message.

Tags are a way of filtering output in your log messages. You can use them to wade through the thousands of log messages you'll see and find the ones you're specifically looking for.

You use the Log functions in Android by accessing the Log.x objects (where the x method is the log level). For example:

Log.d("MyTagGoesHere", "This is my log message at the debug level here");
Log.e("MyTagGoesHere", "This is my log message at the error level here");

I usually make it a point to make the tag my class name so I know where the log message was generated too. Saves a lot of time later on in the game.

You can see your log messages using the logcat tool for android:

adb logcat

Or by opening the eclipse Logcat view by going to the menu bar

Window->Show View->Other then select the Android menu and the LogCat view

Measure string size in Bytes in php

PHP's strlen() function returns the number of ASCII characters.

strlen('borsc') -> 5 (bytes)

strlen('boršc') -> 7 (bytes)

$limit_in_kBytes = 20000;

$pointer = 0;
while(strlen($your_string) > (($pointer + 1) * $limit_in_kBytes)){
    $str_to_handle = substr($your_string, ($pointer * $limit_in_kBytes ), $limit_in_kBytes);
    // here you can handle (0 - n) parts of string

$str_to_handle = substr($your_string, ($pointer * $limit_in_kBytes), $limit_in_kBytes);
// here you can handle last part of string

.. or you can use a function like this:

function parseStrToArr($string, $limit_in_kBytes){
    $ret = array();

    $pointer = 0;
    while(strlen($string) > (($pointer + 1) * $limit_in_kBytes)){
        $ret[] = substr($string, ($pointer * $limit_in_kBytes ), $limit_in_kBytes);

    $ret[] = substr($string, ($pointer * $limit_in_kBytes), $limit_in_kBytes);

    return $ret;

$arr = parseStrToArr($your_string, $limit_in_kBytes = 20000);

What is an example of the Liskov Substitution Principle?

Would implementing ThreeDBoard in terms of an array of Board be that useful?

Perhaps you may want to treat slices of ThreeDBoard in various planes as a Board. In that case you may want to abstract out an interface (or abstract class) for Board to allow for multiple implementations.

In terms of external interface, you might want to factor out a Board interface for both TwoDBoard and ThreeDBoard (although none of the above methods fit).

How to test if a DataSet is empty?

This code will show an error like Table[0] can not be found! because there will not be any table in position 0.

if (ds.Tables[0].Rows.Count == 0)

How to remove all elements in String array in java?

Usually someone uses collections if something frequently changes.


    List<String> someList = new ArrayList<String>();
    // initialize list
    // remove all elements
    // empty list

An ArrayList for example uses a backing Array. The resizing and this stuff is handled automatically. In most cases this is the appropriate way.

How do you create a hidden div that doesn't create a line break or horizontal space?

In addition to CMS´ answer you may want to consider putting the style in an external stylesheet and assign the style to the id, like this:

#divCheckbox {
display: none;

What is

Probably to guarantee that public webservices will be unique.

It always makes me think of delicious deep fried treats...

Resize on div element

There is a really nice, easy to use, lightweight (uses native browser events for detection) plugin for both basic JavaScript and for jQuery that was released this year. It performs perfectly:

Add colorbar to existing axis

This technique is usually used for multiple axis in a figure. In this context it is often required to have a colorbar that corresponds in size with the result from imshow. This can be achieved easily with the axes grid tool kit:

import numpy as np
import matplotlib.pyplot as plt
from mpl_toolkits.axes_grid1 import make_axes_locatable

data = np.arange(100, 0, -1).reshape(10, 10)

fig, ax = plt.subplots()
divider = make_axes_locatable(ax)
cax = divider.append_axes('right', size='5%', pad=0.05)

im = ax.imshow(data, cmap='bone')

fig.colorbar(im, cax=cax, orientation='vertical')

Image with proper colorbar in size

Dynamic height for DIV

You should be okay to just take the height property out of the CSS.

How to call a function within class?

Since these are member functions, call it as a member function on the instance, self.

def isNear(self, p):

Get column index from label in a data frame

The following will do it:


python location on mac osx

i found it here: /Library/Frameworks/Python.framework/Versions/3.6/bin

C pointers and arrays: [Warning] assignment makes pointer from integer without a cast

What are you doing: (I am using bytes instead of in for better reading)

You start with int *ap and so on, so your (your computers) memory looks like this:

-------------- memory used by some one else --------
000: ?
001: ?
098: ?
099: ?
-------------- your memory  --------
100: something          <- here is *ap
101: 41                 <- here starts a[] 
102: 42
103: 43
104: 44
105: 45
106: something          <- here waits x

lets take a look waht happens when (print short cut for ...print("$d", ...)

print a[0]  -> 41   //no surprise
print a     -> 101  // because a points to the start of the array
print *a    -> 41   // again the first element of array
print a+1   -> guess? 102
print *(a+1)    -> whats behind 102? 42 (we all love this number)

and so on, so a[0] is the same as *a, a[1] = *(a+1), ....

a[n] just reads easier.

now, what happens at line 9?

ap=a[4] // we know a[4]=*(a+4) somehow *105 ==>  45 
// warning! converting int to pointer!
-------------- your memory  --------
100: 45         <- here is *ap now 45

x = *ap;   // wow ap is 45 -> where is 45 pointing to?
-------------- memory used by some one else --------
bang!      // dont touch neighbours garden

So the "warning" is not just a warning it's a severe error.

How to extract table as text from the PDF using Python?

If your pdf is text-based and not a scanned document (i.e. if you can click and drag to select text in your table in a PDF viewer), then you can use the module camelot-py with

import camelot
tables = camelot.read_pdf('foo.pdf')

You then can choose how you want to save the tables (as csv, json, excel, html, sqlite), and whether the output should be compressed in a ZIP archive.

tables.export('foo.csv', f='csv', compress=False)

Edit: tabula-py appears roughly 6 times faster than camelot-py so that should be used instead.

import camelot
import cProfile
import pstats
import tabula

cmd_tabula = "tabula.read_pdf('table.pdf', pages='1', lattice=True)"
prof_tabula = cProfile.Profile().run(cmd_tabula)
time_tabula = pstats.Stats(prof_tabula).total_tt

cmd_camelot = "camelot.read_pdf('table.pdf', pages='1', flavor='lattice')"
prof_camelot = cProfile.Profile().run(cmd_camelot)
time_camelot = pstats.Stats(prof_camelot).total_tt

print(time_tabula, time_camelot, time_camelot/time_tabula)


1.8495559890000015 11.057014036000016 5.978199147125147

ab load testing

Steps to set up Apache Bench(AB) on windows (IMO - Recommended).

Step 1 - Install Xampp.
Step 2 - Open CMD.
Step 3 - Go to the apache bench destination (cd C:\xampp\apache\bin) from CMD
Step 4 - Paste the command (ab -n 100 -c 10 -k -H "Accept-Encoding: gzip, deflate" http://localhost:yourport/)
Step 5 - Wait for it. Your done

How to find out line-endings in a text file?

You may use the command todos filename to convert to DOS endings, and fromdos filename to convert to UNIX line endings. To install the package on Ubuntu, type sudo apt-get install tofrodos.

HTML table needs spacing between columns, not rows

<table cellpadding="pixels"cellspacing="pixels"></table>
<td align="position"valign="position"></td>

cellpadding="length in pixels" ~ The cellpadding attribute, used in the <table> tag, specifies how much blank space to display in between the content of each table cell and its respective border. The value is defined as a length in pixels. Hence, a cellpadding="10" attribute-value pair will display 10 pixels of blank space on all four sides of the content of each cell in that table.

cellspacing="length in pixels" ~ The cellspacing attribute, also used in the <table> tag, defines how much blank space to display in between adjacent table cells and in between table cells and the table border. The value is defined as a length in pixels. Hence, a cellspacing="10" attribute-value pair will horizontally and vertically separate all adjacent cells in the respective table by a length of 10 pixels. It will also offset all cells from the table's frame on all four sides by a length of 10 pixels.

Animate a custom Dialog

I've been struggling with Dialog animation today, finally got it working using styles, so here is an example.

To start with, the most important thing — I probably had it working 5 different ways today but couldn't tell because... If your devices animation settings are set to "No Animations" (Settings ? Display ? Animation) then the dialogs won't be animated no matter what you do!

The following is a stripped down version of my styles.xml. Hopefully it is self-explanatory. This should be located in res/values.

<?xml version="1.0" encoding="utf-8"?>
    <style name="PauseDialog" parent="@android:style/Theme.Dialog">
        <item name="android:windowAnimationStyle">@style/PauseDialogAnimation</item>

    <style name="PauseDialogAnimation">
        <item name="android:windowEnterAnimation">@anim/spin_in</item>
        <item name="android:windowExitAnimation">@android:anim/slide_out_right</item>

The windowEnterAnimation is one of my animations and is located in res\anim. The windowExitAnimation is one of the animations that is part of the Android SDK.

Then when I create the Dialog in my activities onCreateDialog(int id) method I do the following.

Dialog dialog = new Dialog(this,;

// Setting the title and layout for the dialog

Alternatively you could set the animations the following way instead of using the Dialog constructor that takes a theme.

Dialog dialog = new Dialog(this);
dialog.getWindow().getAttributes().windowAnimations =;

Repository access denied. access via a deployment key is read-only

here is yhe full code to clone all repos from a given BitBucket team/user

# -*- coding: utf-8 -*-


    Little script to clone all repos from a given BitBucket team/user.

    :copyright: (c) 2019

from git import Repo
from requests.auth import HTTPBasicAuth

import argparse
import json
import os
import requests
import sys

def get_repos(username, password, team):
    bitbucket_api_root = ''
    raw_request = requests.get(bitbucket_api_root + team, auth=HTTPBasicAuth(username, password))
    dict_request = json.loads(raw_request.content.decode('utf-8'))
    repos = dict_request['repositories']

    return repos

def clone_all(repos):
    i = 1
    success_clone = 0
    for repo in repos:
        name = repo['name']
        clone_path = os.path.abspath(os.path.join(full_path, name))

        if os.path.exists(clone_path):
            print('Skipping repo {} of {} because path {} exists'.format(i, len(repos), clone_path))
            # Folder name should be the repo's name
            print('Cloning repo {} of {}. Repo name: {}'.format(i, len(repos), name))
                git_repo_loc = '[email protected]:{}/{}.git'.format(team, name)
                Repo.clone_from(git_repo_loc, clone_path)
                print('Cloning complete for repo {}'.format(name))
                success_clone = success_clone + 1
            except Exception as e:
                print('Unable to clone repo {}. Reason: {} (exit code {})'.format(name, e.stderr, e.status))
        i = i + 1

    print('Successfully cloned {} out of {} repos'.format(success_clone, len(repos)))

parser = argparse.ArgumentParser(description='clooney - clone all repos from a given BitBucket team/user')

                    help='Full path of directory which will hold the cloned repos')

                    help='Bitbucket username')

                    help='Bitbucket password')

                    help='The target team/user')


args = parser.parse_args()

username = args.username
password = args.password
full_path = args.full_path
team =

if not team:
    team = username

if __name__ == '__main__':
        print('Fetching repos...')
        repos = get_repos(username, password, team)
        print('Done: {} repos fetched'.format(len(repos)))
    except Exception as e:
        print('FATAL: Could not get repos: ({}). Terminating script.'.format(e))


More info:

How do you format a Date/Time in TypeScript?

This worked for me

     * Convert Date type to "YYYY/MM/DD" string 
     * - AKA ISO format?
     * - It's logical and sortable :)
     * - 20200227
     * @param Date eg. new Date()
    static DateToYYYYMMDD(Date: Date): string {
        let DS: string = Date.getFullYear()
            + '/' + ('0' + (Date.getMonth() + 1)).slice(-2)
            + '/' + ('0' + Date.getDate()).slice(-2)
        return DS

You can certainly add HH:MM something like this...

    static DateToYYYYMMDD_HHMM(Date: Date): string {
        let DS: string = Date.getFullYear()
            + '/' + ('0' + (Date.getMonth() + 1)).slice(-2)
            + '/' + ('0' + Date.getDate()).slice(-2)
            + ' ' + ('0' + Date.getHours()).slice(-2)
            + ':' + ('0' + Date.getMinutes()).slice(-2)
        return DS

What is the difference between "px", "dip", "dp" and "sp"?

Where to use what & relationship between px & dp?

Density-independent pixel (dp)

A virtual pixel unit that you should use when defining UI layout, to express layout dimensions or position in a density-independent way. As described above, the density-independent pixel is equivalent to one physical pixel on a 160 dpi screen, which is the baseline density assumed by the system for a "medium" density screen. At runtime, the system transparently handles any scaling of the dp units, as necessary, based on the actual density of the screen in use. The conversion of dp units to screen pixels is simple:

px = dp * (dpi / 160).

For example, on a 240 dpi screen, 1 dp equals 1.5 physical pixels. You should always use dp units when defining your application's UI, to ensure proper display of your UI on screens with different densities.

Understanding pixel to dp and vice versa is very essential (especially for giving exact dp values to creative team)

dp = px * 160 / dpi

MDPI = 160 dpi || Therefore, on MDPI 1 px = 1 dp
For example, if you want to convert 20 pixel to dp, use the above formula,
dp = 20 * 160 / 160 = 20.
So, 20 pixel = 20 dp.

HDPI = 240 dpi - So, on HDPI 1.5 px = 1 dp
XHDPI = 320 dpi - So, on XHDPI 2 px = 1 dp
XXHDPI = 480 dpi - So, on XXHDPI 3 px = 1 dp

For example, let us consider Nexus 4.
If 24 pixels to be converted to dp and if it is a Nexus 4 screen, developers can
convert it to dp easily by the following calculation :
dp = 24 * 160 / 320 = 12 dp
Screen dimension:
768 x 1280 pixel resolution (320 ppi or 320dpi)
Optional (screen size):
 4.7" diagonal
  • Try to get all pixel values in even numbers from the creative team. Otherwise precision lose will happen while multiplying with 0.5.


It is explained above. Try to avoid in layout files. But there are some cases, where px is required. for example, ListView divider line. px is better here for giving a one-pixel line as a divider for all across screen resolutions.


Use sp for font sizes. Then only the font inside the application will change while device fonts size changes (that is, Display -> Fonts on Device). If you want to keep a static sized font inside the app, you can give the font dimension in dp. In such a case, it will never change. Developers may get such a requirement for some specific screens, for that, developers can use dp instead of sp. In all other cases, sp is recommended.

What does 'const static' mean in C and C++?

That line of code can actually appear in several different contexts and alghough it behaves approximately the same, there are small differences.

Namespace Scope

// foo.h
static const int i = 0;

'i' will be visible in every translation unit that includes the header. However, unless you actually use the address of the object (for example. '&i'), I'm pretty sure that the compiler will treat 'i' simply as a type safe 0. Where two more more translation units take the '&i' then the address will be different for each translation unit.

static const int i = 0;

'i' has internal linkage, and so cannot be referred to from outside of this translation unit. However, again unless you use its address it will most likely be treated as a type-safe 0.

One thing worth pointing out, is that the following declaration:

const int i1 = 0;

is exactly the same as static const int i = 0. A variable in a namespace declared with const and not explicitly declared with extern is implicitly static. If you think about this, it was the intention of the C++ committee to allow const variables to be declared in header files without always needing the static keyword to avoid breaking the ODR.

Class Scope

class A {
  static const int i = 0;

In the above example, the standard explicitly specifies that 'i' does not need to be defined if its address is not required. In other words if you only use 'i' as a type-safe 0 then the compiler will not define it. One difference between the class and namespace versions is that the address of 'i' (if used in two ore more translation units) will be the same for the class member. Where the address is used, you must have a definition for it:

// a.h
class A {
  static const int i = 0;

#include "a.h"
const int A::i;            // Definition so that we can take the address

Will #if RELEASE work like #if DEBUG does in C#?

No, it won't, unless you do some work.

The important part here is what DEBUG really is, and it's a kind of constant defined that the compiler can check against.

If you check the project properties, under the Build tab, you'll find three things:

  • A text box labelled "Conditional compilation symbols"
  • A check box labelled "Define DEBUG constant"
  • A check box labelled "Define TRACE constant"

There is no such checkbox, nor constant/symbol pre-defined that has the name RELEASE.

However, you can easily add that name to the text box labelled Conditional compilation symbols, but make sure you set the project configuration to Release-mode before doing so, as these settings are per configuration.

So basically, unless you add that to the text box, #if RELEASE won't produce any code under any configuration.

SSIS package creating Hresult: 0x80004005 Description: "Login timeout expired" error

The answer here is not clear, so I wanted to add more detail.

Using the link provided above, I performed the following step.

In my XML config manager I changed the "Provider" to SQLOLEDB.1 rather than SQLNCLI.1. This got me past this error.

This information is available at the link the OP posted in the Answer.

The link the got me there:

TypeError: Cannot read property "0" from undefined

Check your array index to see if it's accessed out of bound.

Once I accessed categories[0]. Later I changed the array name from categories to category but forgot to change the access point--from categories[0] to category[0], thus I also get this error.

JavaScript does a poor debug message. In your case, I reckon probably the access gets out of bound.

Is there a java setting for disabling certificate validation?

On my Mac that I'm sure I'm not going to allow java anyplace other than a specific site, I was able to use Preferences->Java to bring up the Java control panel and turned the checking off. If DLink ever fixes their certificate, I'll turn it back on.

Java control panel - Advanced

How can I represent an 'Enum' in Python?

Why must enumerations be ints? Unfortunately, I can't think of any good looking construct to produce this without changing the Python language, so I'll use strings:

class Enumerator(object):
    def __init__(self, name): = name

    def __eq__(self, other):
        if == other:
            return True
        return self is other

    def __ne__(self, other):
        if != other:
            return False
        return self is other

    def __repr__(self):
        return 'Enumerator({0})'.format(

    def __str__(self):

class Enum(object):
    def __init__(self, *enumerators):
        for e in enumerators:
            setattr(self, e, Enumerator(e))
    def __getitem__(self, key):
        return getattr(self, key)

Then again maybe it's even better now that we can naturally test against strings, for the sake of configuration files or other remote input.


class Cow(object):
    State = Enum(
    state = State.standing

In [1]: from enum import Enum

In [2]: c = Cow()

In [3]: c2 = Cow()

In [4]: c.state, c2.state
Out[4]: (Enumerator(standing), Enumerator(standing))

In [5]: c.state == c2.state
Out[5]: True

In [6]: c.State.mooing
Out[6]: Enumerator(mooing)

In [7]: c.State['mooing']
Out[7]: Enumerator(mooing)

In [8]: c.state = Cow.State.dead

In [9]: c.state == c2.state
Out[9]: False

In [10]: c.state == Cow.State.dead
Out[10]: True

In [11]: c.state == 'dead'
Out[11]: True

In [12]: c.state == Cow.State['dead']
Out[11]: True

Get User Selected Range

Selection is its own object within VBA. It functions much like a Range object.

Selection and Range do not share all the same properties and methods, though, so for ease of use it might make sense just to create a range and set it equal to the Selection, then you can deal with it programmatically like any other range.

Dim myRange as Range
Set myRange = Selection

For further reading, check out the MSDN article.

What is ViewModel in MVC?

A lot of big examples, let me explain in clear and crispy way.

ViewModel = Model that is created to serve the view.

ASP.NET MVC view can't have more than one model so if we need to display properties from more than one models into the view, it is not possible. ViewModel serves this purpose.

View Model is a model class that can hold only those properties that is required for a view. It can also contains properties from more than one entities (tables) of the database. As the name suggests, this model is created specific to the View requirements.

Few examples of View Models are below

  • To list data from more than entities in a view page – we can create a View model and have properties of all the entities for which we want to list data. Join those database entities and set View model properties and return to the View to show data of different entities in one tabular form
  • View model may define only specific fields of a single entity that is required for the View.

ViewModel can also be used to insert, update records into more than one entities however the main use of ViewModel is to display columns from multiple entities (model) into a single view.

The way of creating ViewModel is same as creating Model, the way of creating view for the Viewmodel is same as creating view for Model.

Here is a small example of List data using ViewModel.

Hope this will be useful.

Do I need to explicitly call the base virtual destructor?

What the others said, but also note that you do not have to declare the destructor virtual in the derived class. Once you declare a destructor virtual, as you do in the base class, all derived destructors will be virtual whether you declare them so or not. In other words:

struct A {
   virtual ~A() {}

struct B : public A {
   virtual ~B() {}   // this is virtual

struct C : public A {
   ~C() {}          // this is virtual too

Does Spring Data JPA have any way to count entites using method name resolving?

JpaRepository also extends QueryByExampleExecutor. So you don't even need to define custom methods on your interface:

public interface UserRepository extends JpaRepository<User, Long> {
    // no need of custom method

And then query like:

User probe = new User();
u.setName = "John";
long count = repo.count(Example.of(probe));

live output from subprocess command

None of the Pythonic solutions worked for me. It turned out that or similar may block forever.

Therefore, I use tee like this:'./my_long_running_binary 2>&1 | tee -a my_log_file.txt && exit ${PIPESTATUS}', shell=True, check=True, executable='/bin/bash')

This solution is convenient if you are already using shell=True.

${PIPESTATUS} captures the success status of the entire command chain (only available in Bash). If I omitted the && exit ${PIPESTATUS}, then this would always return zero since tee never fails.

unbuffer might be necessary for printing each line immediately into the terminal, instead of waiting way too long until the "pipe buffer" gets filled. However, unbuffer swallows the exit status of assert (SIG Abort)...

2>&1 also logs stderror to the file.

Getting a list of files in a directory with a glob

You can achieve this pretty easily with the help of NSPredicate, like so:

NSString *bundleRoot = [[NSBundle mainBundle] bundlePath];
NSFileManager *fm = [NSFileManager defaultManager];
NSArray *dirContents = [fm contentsOfDirectoryAtPath:bundleRoot error:nil];
NSPredicate *fltr = [NSPredicate predicateWithFormat:@"self ENDSWITH '.jpg'"];
NSArray *onlyJPGs = [dirContents filteredArrayUsingPredicate:fltr];

If you need to do it with NSURL instead it looks like this:

NSURL *bundleRoot = [[NSBundle mainBundle] bundleURL];
NSArray * dirContents = 
      [fm contentsOfDirectoryAtURL:bundleRoot
NSPredicate * fltr = [NSPredicate predicateWithFormat:@"pathExtension='jpg'"];
NSArray * onlyJPGs = [dirContents filteredArrayUsingPredicate:fltr];

Controlling a USB power supply (on/off) with Linux

I had a problem when connecting my android phone, I couldn't charge my phone because the power switch on and then off ... PowerTop let me find this setting and was useful to fix the issue ( auto value was causing issue):

echo 'on' | sudo tee /sys/bus/usb/devices/1-1/power/control

Android open pdf file

The problem is that there is no app installed to handle opening the PDF. You should use the Intent Chooser, like so:

File file = new File(Environment.getExternalStorageDirectory().getAbsolutePath() +"/"+ filename);
Intent target = new Intent(Intent.ACTION_VIEW);

Intent intent = Intent.createChooser(target, "Open File");
try {
} catch (ActivityNotFoundException e) {
    // Instruct the user to install a PDF reader here, or something

How to check if an Object is a Collection Type in Java?

Update: there are two possible scenarios here:

  1. You are determining if an object is a collection;

  2. You are determining if a class is a collection.

The solutions are slightly different but the principles are the same. You also need to define what exactly constitutes a "collection". Implementing either Collection or Map will cover the Java Collections.

Solution 1:

public static boolean isCollection(Object ob) {
  return ob instanceof Collection || ob instanceof Map;

Solution 2:

public static boolean isClassCollection(Class c) {
  return Collection.class.isAssignableFrom(c) || Map.class.isAssignableFrom(c);

(1) can also be implemented in terms of (2):

public static boolean isCollection(Object ob) {
  return ob != null && isClassCollection(ob.getClass());

I don't think the efficiency of either method will be greatly different from the other.

List of all unique characters in a string?

Use an OrderedDict. This will ensure that the order is preserved

>>> ''.join(OrderedDict.fromkeys( "aaabcabccd").keys())

PS: I just timed both the OrderedDict and Set solution, and the later is faster. If order does not matter, set should be the natural solution, if Order Matter;s this is how you should do.

>>> from timeit import Timer
>>> t1 = Timer(stmt=stmt1, setup="from __main__ import data, OrderedDict")
>>> t2 = Timer(stmt=stmt2, setup="from __main__ import data")
>>> t1.timeit(number=1000)
>>> t2.timeit(number=1000)

How to display Oracle schema size with SQL query?

select T.TABLE_NAME, T.TABLESPACE_NAME, t.avg_row_len*t.num_rows from dba_tables t
order by T.TABLE_NAME asc

See e.g. for more options

Where is the Query Analyzer in SQL Server Management Studio 2008 R2?

You can use Database Engine Tuning Advisor.

This tool is for improving the query performances by examining the way queries are processed and recommended enhancements by specific indexes.

How to use the Database Engine Tuning Advisor?

1- Copy the select statement that you need to speed up into the new query.

2- Parse (Ctrl+F5).

3- Press The Icon of the (Database Engine Tuning Advisor).

isset() and empty() - what to use

$var = 'abcdef';
   if (strlen($var) > 0);
      //do something, string length greater than zero
     //do something else, string length 0 or less

This is a simple example. Hope it helps.

edit: added isset in the event a variable isn't defined like above, it would cause an error, checking to see if its first set at the least will help remove some headache down the road.

jQuery onclick toggle class name

jQuery has a toggleClass function:

<button class="switch">Click me</button>

<div class="text-block collapsed pressed">some text</div>

    $('.switch').on('click', function(e) {
      $('.text-block').toggleClass("collapsed pressed"); //you can list several class names 

Disable browsers vertical and horizontal scrollbars

(I can't comment yet, but wanted to share this):

Lyncee's code worked for me in desktop browser. However, on iPad (Chrome, iOS 9), it crashed the application. To fix it, I changed = ...

to = ...

which solved my problem.

How can I color a UIImage in Swift?

Here is swift 3 version of H R's solution.

func overlayImage(color: UIColor) -> UIImage? {
    UIGraphicsBeginImageContextWithOptions(self.size, false, UIScreen.main.scale)
    let context = UIGraphicsGetCurrentContext()


    context!.translateBy(x: 0, y: self.size.height)
    context!.scaleBy(x: 1.0, y: -1.0)

    let rect = CGRect(x: 0, y: 0, width: self.size.width, height: self.size.height)
    context!.draw(self.cgImage!, in: rect)

    context!.drawPath(using: CGPathDrawingMode.fill)

    let coloredImage = UIGraphicsGetImageFromCurrentImageContext()

    return coloredImage

How to connect to remote Oracle DB with PL/SQL Developer?

I am facing to this problem so many times till I have 32bit PL/SQL Developer and 64bit Oracle DB or Oracle Client.

The solution is:

  1. install a 32bit client.
  2. set PLSQL DEV-Tools-Preferencies-Oracle Home to new 32bit client Home
  3. set PLSQL DEV-Tools-Preferencies-OCI to new 32 bit home /bin/oci.dll For example: c:\app\admin\product\11.2.0\client_1\BIN\oci.dll
  4. Save and restart PLSQL DEV.

Edit or create a TNSNAMES.ORA file in c:\app\admin\product\11.2.0\client_1\NETWORK\admin folder like mentioned above.

Try with TNSPING in console like

C:>tnsping ORCL

If still have problem, set the TNS_ADMIN Enviroment properties value pointing to the folder where the TNSNAMES.ORA located, like: c:\app\admin\product\11.2.0\client_1\network\admin

Show/hide 'div' using JavaScript

Just Simple Function Need To implement Show/hide 'div' using JavaScript

<a id="morelink" class="link-more" style="font-weight: bold; display: block;" onclick="'none'; document.getElementById('states').style.display='block'; return false;">READ MORE</a>

<div id="states" style="display: block; line-height: 1.6em;">
 text here text here text here text here text here text here text here text here text here text here text here text here text here text here text here text here text here text here text here text here  
    <a class="link-less" style="font-weight: bold;" onclick="document.getElementById('morelink').style.display='inline-block'; document.getElementById('states').style.display='none'; return false;">LESS INFORMATION</a>

How to clear radio button in Javascript?

If you have a radio button with same id, then you can clear the selection

Radio Button definition :

<input type="radio" name="paymentType" id="paymentType" value="CASH" /> CASH
<input type="radio" name="paymentType" id="paymentType" value="CHEQUE" /> CHEQUE
<input type="radio" name="paymentType" id="paymentType" value="DD" /> DD

Clearing all values of radio button:

document.formName.paymentType[0].checked = false;
document.formName.paymentType[1].checked = false;
document.formName.paymentType[2].checked = false;

Delete files in subfolder using batch script

I had to complete the same task and I used a "for" loop and a "del" command as follows:


set dir=%cd%

FOR /d /r %dir% %%x in (archive\) do (
    if exist "%%x" del %%x\*.txt /f /q

You can set the dir variable with any start directory you want or used the current directory (%cd%) variable.

These are the options for "for" command:

  • /d For directories
  • /r For recursive

These are the options for "del" command:

  • /f Force deletes read-only files
  • /q Quiet mode; suppresses prompts for delete confirmations.

How to prevent rm from reporting that a file was not found?

\rm -f file will never report not found.

How do I add my bot to a channel?

As of now:

  • Only the creator of the channel can add a bot.
  • Other administrators can't add bots to channels.
  • Channel can be public or private (doesn't matter)
  • bots can be added only as admins, not members.*

To add the bot to your channel:

  • click on the channel name: enter image description here

  • click on admins: enter image description here

  • click on Add Admin: enter image description here

  • search for your bot like @your_bot_name, and click add:** enter image description here

* In some platforms like mac native telegram client it may look like that you can add bot as a member, but at the end it won't work.
** the bot doesn't need to be in your contact list.

Setting custom UITableViewCells height

Your UITableViewDelegate should implement tableView:heightForRowAtIndexPath:


- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
    return [indexPath row] * 20;

Swift 5

func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
    return indexPath.row * 20

You will probably want to use NSString's sizeWithFont:constrainedToSize:lineBreakMode: method to calculate your row height rather than just performing some silly math on the indexPath :)

Python vs. Java performance (runtime speed)

There is no good answer as Python and Java are both specifications for which there are many different implementations. For example, CPython, IronPython, Jython, and PyPy are just a handful of Python implementations out there. For Java, there is the HotSpot VM, the Mac OS X Java VM, OpenJRE, etc. Jython generates Java bytecode, and so it would be using more-or-less the same underlying Java. CPython implements quite a handful of things directly in C, so it is very fast, but then again Java VMs also implement many functions in C. You would probably have to measure on a function-by-function basis and across a variety of interpreters and VMs in order to make any reasonable statement.

How to get device make and model on iOS?

Below Function Perfectly Working on iOS7 or later version in Swift

func DeviceName()-> String {

        var myDeviceName : String = String()

        var systemInfo = [UInt8](count: sizeof(utsname), repeatedValue: 0)

        let model = systemInfo.withUnsafeMutableBufferPointer { (inout body: UnsafeMutableBufferPointer<UInt8>) -> String? in

            if uname(UnsafeMutablePointer(body.baseAddress)) != 0 {
                return nil

            return String.fromCString(UnsafePointer(body.baseAddress.advancedBy(Int(_SYS_NAMELEN * 4))))

        let deviceNamesByCode : [String: String] = ["iPod1,1":"iPod Touch 1",
                                                    "iPod2,1":"iPod Touch 2",
                                                    "iPod3,1":"iPod Touch 3",
                                                    "iPod4,1":"iPod Touch 4",
                                                    "iPod5,1":"iPod Touch 5",
                                                    "iPod7,1":"iPod Touch 6",
                                                    "iPhone1,2":"iPhone ",
                                                    "iPhone2,1":"iPhone ",
                                                    "iPhone3,1":"iPhone 4",
                                                    "iPhone3,2":"iPhone 4",
                                                    "iPhone3,3":"iPhone 4",
                                                    "iPhone4,1":"iPhone 4s",
                                                    "iPhone5,1":"iPhone 5",
                                                    "iPhone5,2":"iPhone 5",
                                                    "iPhone5,3":"iPhone 5c",
                                                    "iPhone5,4":"iPhone 5c",
                                                    "iPhone6,1":"iPhone 5s",
                                                    "iPhone6,2":"iPhone 5s",
                                                    "iPhone7,2":"iPhone 6",
                                                    "iPhone7,1":"iPhone 6 Plus",
                                                    "iPhone8,1":"iPhone 6s",
                                                    "iPhone8,2":"iPhone 6s Plus",
                                                    "iPhone8,4":"iPhone SE",
                                                    "iPad2,1":"iPad 2",
                                                    "iPad2,2":"iPad 2",
                                                    "iPad2,3":"iPad 2",
                                                    "iPad2,4":"iPad 2",
                                                    "iPad3,1":"iPad 3",
                                                    "iPad3,2":"iPad 3",
                                                    "iPad3,3":"iPad 3",
                                                    "iPad3,4":"iPad 4",
                                                    "iPad3,5":"iPad 4",
                                                    "iPad3,6":"iPad 4",
                                                    "iPad4,1":"iPad Air",
                                                    "iPad4,2":"iPad Air",
                                                    "iPad4,3":"iPad Air",
                                                    "iPad5,3":"iPad Air 2",
                                                    "iPad5,4":"iPad Air 2",
                                                    "iPad2,5":"iPad Mini",
                                                    "iPad2,6":"iPad Mini",
                                                    "iPad2,7":"iPad Mini",
                                                    "iPad4,4":"iPad Mini 2",
                                                    "iPad4,5":"iPad Mini 2",
                                                    "iPad4,6":"iPad Mini 2",
                                                    "iPad4,7":"iPad Mini 3",
                                                    "iPad4,8":"iPad Mini 3",
                                                    "iPad4,9":"iPad Mini 3",
                                                    "iPad5,1":"iPad Mini 4",
                                                    "iPad5,2":"iPad Mini 4",
                                                    "iPad6,3":"iPad Pro",
                                                    "iPad6,4":"iPad Pro",
                                                    "iPad6,7":"iPad Pro",
                                                    "iPad6,8":"iPad Pro",
                                                    "AppleTV5,3":"Apple TV",


        if model!.characters.count > 0 {
            myDeviceName = deviceNamesByCode[model!]!
            myDeviceName = UIDevice.currentDevice().model

        return myDeviceName


how to release localhost from Error: listen EADDRINUSE


ps -ax | grep node

You'll get something like:

60778 ??         0:00.62 /usr/local/bin/node abc.js

Then do:

kill -9 60778

How to programmatically log out from Facebook SDK 3.0 without using Facebook login/logout button?

Since Facebook's Android SDK v4.0 you need to execute the following:


This is not sufficient. This will simply clear cached access token and profile so that AccessToken.getCurrentAccessToken() and Profile.getCurrentProfile() will now become null.

To completely logout you need to revoke permissions and then call LoginManager.getInstance().logOut();. To revoke permission execute following graph API -

    GraphRequest delPermRequest = new GraphRequest(AccessToken.getCurrentAccessToken(), "/{user-id}/permissions/", null, HttpMethod.DELETE, new GraphRequest.Callback() {
        public void onCompleted(GraphResponse graphResponse) {
                FacebookRequestError error =graphResponse.getError();
                    Log.e(TAG, error.toString());
                }else {
    Log.d(TAG,"Executing revoke permissions with graph path" + delPermRequest.getGraphPath());

How to remove the arrows from input[type="number"] in Opera

Those arrows are part of the Shadow DOM, which are basically DOM elements on your page which are hidden from you. If you're new to the idea, a good introductory read can be found here.

For the most part, the Shadow DOM saves us time and is good. But there are instances, like this question, where you want to modify it.

You can modify these in Webkit now with the right selectors, but this is still in the early stages of development. The Shadow DOM itself has no unified selectors yet, so the webkit selectors are proprietary (and it isn't just a matter of appending -webkit, like in other cases).

Because of this, it seems likely that Opera just hasn't gotten around to adding this yet. Finding resources about Opera Shadow DOM modifications is tough, though. A few unreliable internet sources I've found all say or suggest that Opera doesn't currently support Shadow DOM manipulation.

I spent a bit of time looking through the Opera website to see if there'd be any mention of it, along with trying to find them in Dragonfly...neither search had any luck. Because of the silence on this issue, and the developing nature of the Shadow DOM + Shadow DOM manipulation, it seems to be a safe conclusion that you just can't do it in Opera, at least for now.

Run PostgreSQL queries from the command line

I also noticed that the query

SELECT * FROM tablename;

gives an error on the psql command prompt and

SELECT * FROM "tablename";

runs fine, really strange, so don't forget the double quotes. I always liked databases :-(

How to create a DataFrame from a text file in Spark

I have given different ways to create DataFrame from text file

val conf = new SparkConf().setAppName(appName).setMaster("local")
val sc = SparkContext(conf)

raw text file

val file = sc.textFile("C:\\vikas\\spark\\Interview\\text.txt")
val fileToDf =",")).map{case Array(a,b,c) => 

spark session without schema

import org.apache.spark.sql.SparkSession
val sparkSess = 

val df ="header", 

spark session with schema

import org.apache.spark.sql.types._
val schemaString = "name age city"
val fields = schemaString.split(" ").map(fieldName => StructField(fieldName, 
StringType, nullable=true))
val schema = StructType(fields)

val dfWithSchema ="header", 

using sql context

import org.apache.spark.sql.SQLContext

val fileRdd = 
=> org.apache.spark.sql.Row(x:_*)}
val sqlDf = sqlCtx.createDataFrame(fileRdd,schema)

How to convert SSH keypairs generated using PuTTYgen (Windows) into key-pairs used by ssh-agent and Keychain (Linux)

Newer versions of PuTTYgen (mine is 0.64) are able to show the OpenSSH public key to be pasted in the linux system in the .ssh/authorized_keys file, as shown in the following image:

enter image description here

Multi-gradient shapes

Try this method then you can do every thing you want.
It is like a stack so be careful which item comes first or last.

<?xml version="1.0" encoding="utf-8"?>
<item android:right="50dp" android:start="10dp" android:left="10dp">
        <corners android:radius="3dp" />
        <solid android:color="#012d08"/>
<item android:top="50dp">
    <shape android:shape="rectangle">
        <solid android:color="#7c4b4b" />
<item android:top="90dp" android:end="60dp">
    <shape android:shape="rectangle">
        <solid android:color="#e2cc2626" />
<item android:start="50dp" android:bottom="20dp" android:top="120dp">
    <shape android:shape="rectangle">
        <solid android:color="#360e0e" />

Creating email templates with Django

send_emai() didn't work for me so I used EmailMessage here in django docs.

I have included two versions of the anser:

  1. With html email version only
  2. With plain text email and html email versions
from django.template.loader import render_to_string 
from django.core.mail import EmailMessage

# import file with html content
html_version = 'path/to/html_version.html'

html_message = render_to_string(html_version, { 'context': context, })

message = EmailMessage(subject, html_message, from_email, [to_email])
message.content_subtype = 'html' # this is required because there is no plain text email version

If you want to include a plain text version of your email, modify the above like this:

from django.template.loader import render_to_string 
from django.core.mail import EmailMultiAlternatives # <= EmailMultiAlternatives instead of EmailMessage

plain_version = 'path/to/plain_version.html' # import plain version. No html content
html_version = 'path/to/html_version.html' # import html version. Has html content

plain_message = render_to_string(plain_version, { 'context': context, })
html_message = render_to_string(html_version, { 'context': context, })

message = EmailMultiAlternatives(subject, plain_message, from_email, [to_email])
message.attach_alternative(html_message, "text/html") # attach html version

My plain and html versions look like this: plain_version.html:

Plain text {{ context }}


<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "">
<html xmlns="">
<table align="center" border="0" cellpadding="0" cellspacing="0" width="320" style="border: none; border-collapse: collapse; font-family:  Arial, sans-serif; font-size: 14px; line-height: 1.5;">
{{ context }}

Unfortunately Launcher3 has stopped working error in android studio?

May 2017; I had the same issue, could not even get to apps as it just cycled between starting and stopping. Went into avd settings, edited the multi core (unticked the box) and set graphics to software Gles. It appears to have fixed the issue

How, in general, does Node.js handle 10,000 concurrent requests?

Adding to slebetman answer: When you say Node.JS can handle 10,000 concurrent requests they are essentially non-blocking requests i.e. these requests are majorly pertaining to database query.

Internally, event loop of Node.JS is handling a thread pool, where each thread handles a non-blocking request and event loop continues to listen to more request after delegating work to one of the thread of the thread pool. When one of the thread completes the work, it send a signal to the event loop that it has finished aka callback. Event loop then process this callback and send the response back.

As you are new to NodeJS, do read more about nextTick to understand how event loop works internally. Read blogs on, they were really helpful for me when I started with JavaScript/NodeJS.

ASP.NET MVC Html.ValidationSummary(true) does not display model errors

I know this is kind of old and has been marked as answers with 147 up votes, but there is something else to consider.

You can have all the model errors, the property named and string.Empty keys alike, be shown in the ValidationSummary if you need to. There is an overload in the ValidationSummary that will do this.

    //   excludePropertyErrors:
    //   true to have the summary display model-level errors only, or false to have
    //   the summary display all errors.
    public static MvcHtmlString ValidationSummary(this HtmlHelper htmlHelper, bool excludePropertyErrors);

enter image description here

Find records with a date field in the last 24 hours

SELECT * FROM news WHERE date < DATEADD(Day, -1, date)

Best data type to store money values in MySQL

If GAAP Compliance is required or you need 4 decimal places:

DECIMAL(13, 4) Which supports a max value of:


Otherwise, if 2 decimal places is enough: DECIMAL(13,2)


How do I use dataReceived event of the SerialPort Port Object in C#?

By the way, you can use next code in you event handler:

  case SerialData.Chars:
    // means you receives something
  case SerialData.Eof:
    // means receiving ended

How to run html file on localhost?

You can install Xampp and run apache serve and place your file to www folder and access your file at localhost/{file name} or simply at localhost if your file is named index.html

rails 3.1.0 ActionView::Template::Error (application.css isn't precompiled)

I was having the exact same error in my development environment. In the end all I needed to do in order to fix it was to add:

config.assets.manifest = Rails.root.join("public/assets")

to my config/environments/development.rb file and it fixed it. My final config in development related to assets looks like:

config.assets.compress = false  
config.assets.precompile += %w[bootstrap-alerts.js] #Lots of other space separated files
config.assets.compile = false
config.assets.digest = true
config.assets.manifest = Rails.root.join("public/assets")
config.assets.debug = true

pass post data with window.location.href

Short answer: no. window.location.href is not capable of passing POST data.

Somewhat more satisfying answer: You can use this function to clone all your form data and submit it.

var submitMe = document.createElement("form");
submitMe.action = "YOUR_URL_HERE"; // Remember to change me
submitMe.method = "post";
submitMe.enctype = "multipart/form-data";
var nameJoiner = "_";
// ^ The string used to join form name and input name
//   so that you can differentiate between forms when
//   processing the data server-side.
submitMe.importFields = function(form){
    for(k in form.elements){
        if(input = form.elements[k]){
                var output = input.cloneNode(true);
       = + nameJoiner +;
  • Do submitMe.importFields(form_element); for each of the three forms you want to submit.
  • This function will add each form's name to the names of its child inputs (If you have an <input name="email"> in <form name="login">, the submitted name will be login_name.
  • You can change the nameJoiner variable to something other than _ so it doesn't conflict with your input naming scheme.
  • Once you've imported all the necessary forms, do submitMe.submit();

How to recover corrupted Eclipse workspace?

I also experienced an issue like this, my workspace was corrupted and didn't do all the important things anymore.

For some reason, I had a corrupt resource on one of my projects. It didn't show up in the package tree, but it did show in the error log in Eclipse as

Error while creating a link for external folder X:\somefolder

After checking every project (because the error didn't point to one), I indeed found this resource in one of the build paths (in Configure Build Path menu it did show an error icon!) and deleted it.

See Eclipse (Kepler) Workspace acting weird (type hierarchy, searching for references not working) for a wider description of my issue if you're experiencing something similar.

Posted this for future developers to reference.

Difference between Method and Function?

From Object-Oriented Programming Concept:

If you have a function that is accessing/muttating the fields of your class, it becomes method. Otherwise, it is a function.

It will not be a crime if you keep calling all the functions in Java/C++ classes as methods. The reason is that you are directly/indirectly accessing/mutating class properties. So why not all the functions in Java/C++ classes are methods?

Why is my variable unaltered after I modify it inside of a function? - Asynchronous code reference

Here's a more concise answer for people that are looking for a quick reference as well as some examples using promises and async/await.

Start with the naive approach (that doesn't work) for a function that calls an asynchronous method (in this case setTimeout) and returns a message:

function getMessage() {
  var outerScopeVar;
  setTimeout(function() {
    outerScopeVar = 'Hello asynchronous world!';
  }, 0);
  return outerScopeVar;

undefined gets logged in this case because getMessage returns before the setTimeout callback is called and updates outerScopeVar.

The two main ways to solve it are using callbacks and promises:


The change here is that getMessage accepts a callback parameter that will be called to deliver the results back to the calling code once available.

function getMessage(callback) {
  setTimeout(function() {
    callback('Hello asynchronous world!');
  }, 0);
getMessage(function(message) {


Promises provide an alternative which is more flexible than callbacks because they can be naturally combined to coordinate multiple async operations. A Promises/A+ standard implementation is natively provided in node.js (0.12+) and many current browsers, but is also implemented in libraries like Bluebird and Q.

function getMessage() {
  return new Promise(function(resolve, reject) {
    setTimeout(function() {
      resolve('Hello asynchronous world!');
    }, 0);

getMessage().then(function(message) {

jQuery Deferreds

jQuery provides functionality that's similar to promises with its Deferreds.

function getMessage() {
  var deferred = $.Deferred();
  setTimeout(function() {
    deferred.resolve('Hello asynchronous world!');
  }, 0);
  return deferred.promise();

getMessage().done(function(message) {


If your JavaScript environment includes support for async and await (like Node.js 7.6+), then you can use promises synchronously within async functions:

function getMessage () {
    return new Promise(function(resolve, reject) {
        setTimeout(function() {
            resolve('Hello asynchronous world!');
        }, 0);

async function main() {
    let message = await getMessage();


What is the error "Every derived table must have its own alias" in MySQL?

I arrived here because I thought I should check in SO if there are adequate answers, after a syntax error that gave me this error, or if I could possibly post an answer myself.

OK, the answers here explain what this error is, so not much more to say, but nevertheless I will give my 2 cents using my words:

This error is caused by the fact that you basically generate a new table with your subquery for the FROM command.

That's what a derived table is, and as such, it needs to have an alias (actually a name reference to it).

So given the following hypothetical query:

SELECT id, key1
    SELECT t1.ID id, t2.key1 key1, t2.key2 key2, t2.key3 key3
    FROM table1 t1 
    LEFT JOIN table2 t2 ON =
    WHERE t2.key3 = 'some-value'
) AS tt

So, at the end, the whole subquery inside the FROM command will produce the table that is aliased as tt and it will have the following columns id, key1, key2, key3.

So, then with the initial SELECT from that table we finally select the id and key1 from the tt.

'if' in prolog?

There are essentially three different ways how to express something like if-then-else in Prolog. To compare them consider char_class/2. For a and b the class should be ab and other for all other terms. One could write this clumsily like so:

char_class(a, ab).
char_class(b, ab).
char_class(X, other) :-
   dif(X, a),
   dif(X, b).

?- char_class(Ch, Class).
   Ch = a, Class = ab
;  Ch = b, Class = ab
;  Class = other,
   dif(Ch, a), dif(Ch, b).

To write things more compactly, an if-then-else construct is needed. Prolog has a built-in one:

?- ( ( Ch = a ; Ch = b ) -> Class = ab ; Class = other ).
   Ch = a, Class = ab.

While this answer is sound, it is incomplete. Just the first answer from ( Ch = a ; Ch = b ) is given. The other answers are chopped away. Not very relational, indeed.

A better construct, often called a "soft cut" (don't believe the name, a cut is a cut is a cut), gives slightly better results (this is in YAP):

?- ( ( Ch = a ; Ch = b ) *-> Class = ab ; Class = other ).
   Ch = a, Class = ab
;  Ch = b, Class = ab.

Alternatively, SICStus has if/3 with very similar semantics:

?- if( ( Ch = a ; Ch = b ), Class = ab , Class = other ).
   Ch = a, Class = ab
;  Ch = b, Class = ab.

So the last answer is still suppressed. Now enter library(reif) for SICStus, YAP, and SWI. Install it and say:

?- use_module(library(reif)).

?- if_( ( Ch = a ; Ch = b ), Class = ab , Class = other ).
   Ch = a, Class = ab
;  Ch = b, Class = ab
;  Class = other,
   dif(Ch, a), dif(Ch, b).

Note that all the if_/3 is compiled away to a wildly nested if-then-else for

char_class(Ch, Class) :-
   if_( ( Ch = a ; Ch = b ), Class = ab , Class = other ).

which expands in YAP 6.3.4 to:

char_class(A,B) :-
   ( A\=a
     ( A\=b
       ( A==b
     ( A==a
     ( A\=b
       ( A==b

file_put_contents: Failed to open stream, no such file or directory

I was also stuck on the same kind of problem and I followed the simple steps below.

Just get the exact url of the file to which you want to copy, for example: (file to copy)

Then pass the exact absolute folder path with filename where you do want to write that file.

  1. If you are on a Windows machine then d:/xampp/htdocs/upload/test.txt

  2. If you are on a Linux machine then /var/www/html/upload/test.txt

You can get the document root with the PHP function $_SERVER['DOCUMENT_ROOT'].

JavaScript: IIF like statement

I typed this in my URL bar:

javascript:{ var col = 'screwdriver'; var x = '<option value="' + col + '"' + ((col == 'screwdriver') ? ' selected' : '') + '>Very roomy</option>'; alert(x); }

How to embed a Google Drive folder in a website

Google Drive folders can be embedded and displayed in list and grid views:

List view

<iframe src="" style="width:100%; height:600px; border:0;"></iframe>

Grid view

<iframe src="" style="width:100%; height:600px; border:0;"></iframe>

Q: What is a folder ID (FOLDER-ID) and how can I get it?

A: Go to Google Drive >> open the folder >> look at its URL in the address bar of your browser. For example:

Folder URL:

Folder ID:

Caveat with folders requiring permission

This technique works best for folders with public access. Folders that are shared only with certain Google accounts will cause trouble when you embed them this way. At the time of this edit, a message "You need permission" appears, with some buttons to help you "Request access" or "Switch accounts" (or possibly sign-in to a Google account). The Javascript in these buttons doesn't work properly inside an IFRAME in Chrome.

Read more at!msg/drive/GpVgCobPL2Y/_Xt7sMc1WzoJ

Unity 2d jumping script

Use Addforce() method of a rigidbody compenent, make sure rigidbody is attached to the object and gravity is enabled, something like this

gameObj.rigidbody2D.AddForce(Vector3.up * 10 * Time.deltaTime); or 
gameObj.rigidbody2D.AddForce(Vector3.up * 1000); 

See which combination and what values matches your requirement and use accordingly. Hope it helps

Loading cross-domain endpoint with AJAX

If the external site doesn't support JSONP or CORS, your only option is to use a proxy.

Build a script on your server that requests that content, then use jQuery ajax to hit the script on your server.

Which "href" value should I use for JavaScript links, "#" or "javascript:void(0)"?

I use href="#" for links that I want a dummy behaviour for. Then I use this code:

$(document).ready(function() {
    $("a[href='#']").click(function(event) {

Meaning if the href equals to a hash (*="#") it prevents the default link behaviour, thus still allowing you to write functionality for it, and it doesn't affect anchor clicks.

How to add a class to a given element?

You can use the classList.add OR classList.remove method to add/remove a class from a element.

var nameElem = document.getElementById("name")

The above code will add(and NOT replace) a class "anyclass" to nameElem. Similarly you can use classList.remove() method to remove a class.


Get last 3 characters of string

The easiest way would be using Substring

string str = "AM0122200204";
string substr = str.Substring(str.Length - 3);

Using the overload with one int as I put would get the substring of a string, starting from the index int. In your case being str.Length - 3, since you want to get the last three chars.

Add leading zeroes to number in Java?

Since Java 1.5 you can use the String.format method. For example, to do the same thing as your example:

String format = String.format("%0%d", digits);
String result = String.format(format, num);
return result;

In this case, you're creating the format string using the width specified in digits, then applying it directly to the number. The format for this example is converted as follows:

%% --> %
0  --> 0
%d --> <value of digits>
d  --> d

So if digits is equal to 5, the format string becomes %05d which specifies an integer with a width of 5 printing leading zeroes. See the java docs for String.format for more information on the conversion specifiers.

Split a large dataframe into a list of data frames based on common value in column

Stumbled across this answer and I actually wanted BOTH groups (data containing that one user and data containing everything but that one user). Not necessary for the specifics of this post, but I thought I would add in case someone was googling the same issue as me.

df <- data.frame(
     g=rep(factor(LETTERS[1:5]), 25)

test_x = split(df,df$g)[['A']]
test_y = split(df,df$g!='A')[['TRUE']]

Here's what it looks like:

            x          y g
1   1.1362198  1.2969541 A
6   0.5510307 -0.2512449 A
11  0.0321679  0.2358821 A
16  0.4734277 -1.2889081 A
21 -1.2686151  0.2524744 A

> head(test_y)
            x          y g
2 -2.23477293  1.1514810 B
3 -0.46958938 -1.7434205 C
4  0.07365603  0.1111419 D
5 -1.08758355  0.4727281 E
7  0.28448637 -1.5124336 B
8  1.24117504  0.4928257 C

AngularJS POST Fails: Response for preflight has invalid HTTP status code 404

For a Node.js app, in the server.js file before registering all of my own routes, I put the code below. It sets the headers for all responses. It also ends the response gracefully if it is a pre-flight "OPTIONS" call and immediately sends the pre-flight response back to the client without "nexting" (is that a word?) down through the actual business logic routes. Here is my server.js file. Relevant sections highlighted for Stackoverflow use.

// server.js

// ==================

// import the packages we need
var express    = require('express');
var app        = express();
var bodyParser = require('body-parser');
var morgan     = require('morgan');
var jwt        = require('jsonwebtoken'); // used to create, sign, and verify tokens

// ====================================================
// configure app to use bodyParser()
// this will let us get the data from a POST
app.use(bodyParser.urlencoded({ extended: true }));

// Logger

// -------------------------------------------------------------
// -------------------------------------------------------------

//Set CORS header and intercept "OPTIONS" preflight call from AngularJS
var allowCrossDomain = function(req, res, next) {
    res.header('Access-Control-Allow-Origin', '*');
    res.header('Access-Control-Allow-Methods', 'GET,PUT,POST,DELETE');
    res.header('Access-Control-Allow-Headers', 'Content-Type');
    if (req.method === "OPTIONS") 

// -------------------------------------------------------------
// -------------------------------------------------------------

// =================================================

var route1 = require("./routes/route1");
var route2 = require("./routes/route2");
var error404 = require("./routes/error404");

// ======================================================

// -------------------------------------------------------------
// -------------------------------------------------------------


// -------------------------------------------------------------
// -------------------------------------------------------------

app.use("/api/v1/route1/", route1);
app.use("/api/v1/route2/", route2);
app.use('/', error404);

// =================

var port = process.env.PORT || 8080;        // set our port
console.log('API Active on port ' + port);

How to get child element by index in Jquery?


Where do I find the current C or C++ standard documents?

The ISO C and C++ standards are bloody expensive. On the other hand, the INCITS republishes them for a lot less. seems to have the PDF for $30 (search for INCITS/ISO/IEC 14882:2003).

Hardcopy versions are available, too. Look for the British Standards Institute versions, published by Wiley.

How can I easily switch between PHP versions on Mac OSX?

If you have both versions of PHP installed, you can switch between versions using the link and unlink brew commands.

For example, to switch between PHP 7.4 and PHP 7.3

brew unlink [email protected]
brew link [email protected]

PS: both versions of PHP have be installed for these commands to work.

Saving an image in OpenCV

i think, simply camera not initialize in first frame. Try to save image after 10 frames.

Javascript - removing undefined fields from an object

Here's a plain javascript (no library required) solution:

function removeUndefinedProps(obj) {
    for (var prop in obj) {
        if (obj.hasOwnProperty(prop) && obj[prop] === undefined) {
            delete obj[prop];

Working demo:

How to set default values in Go structs

  1. Force a method to get the struct (the constructor way).

    From this post:

    A good design is to make your type unexported, but provide an exported constructor function like NewMyType() in which you can properly initialize your struct / type. Also return an interface type and not a concrete type, and the interface should contain everything others want to do with your value. And your concrete type must implement that interface of course.

    This can be done by simply making the type itself unexported. You can export the function NewSomething and even the fields Text and DefaultText, but just don't export the struct type something.

  2. Another way to customize it for you own module is by using a Config struct to set default values (Option 5 in the link). Not a good way though.

multiple packages in context:component-scan, spring config

<context:component-scan base-package="x.y.z"/>

will work since the rest of the packages are sub packages of "x.y.z". Thus, you dont need to mention each package individually.

How to convert a HTMLElement to a string

The most easy way to do is copy innerHTML of that element to tmp variable and make it empty, then append new element, and after that copy back tmp variable to it. Here is an example I used to add jquery script to top of head.

var imported = document.createElement('script');
imported.src = '';
var tmpHead = document.head.innerHTML;
document.head.innerHTML = "";
document.head.innerHTML += tmpHead;

That simple :)

java.util.Date to XMLGregorianCalendar

Here is a method for converting from a GregorianCalendar to XMLGregorianCalendar; I'll leave the part of converting from a java.util.Date to GregorianCalendar as an exercise for you:

import java.util.GregorianCalendar;

import javax.xml.datatype.DatatypeFactory;
import javax.xml.datatype.XMLGregorianCalendar;

public class DateTest {

   public static void main(final String[] args) throws Exception {
      GregorianCalendar gcal = new GregorianCalendar();
      XMLGregorianCalendar xgcal = DatatypeFactory.newInstance()


EDIT: Slooow :-)

MongoDB: How to update multiple documents with a single command?

To Update Entire Collection,

{$set: {"field1" : "value1", "field2" : "value2", "field3" : "value3"}},
{multi: true })

Easiest way to make lua script wait/pause/sleep/block for a few seconds?

It's also easy to use Alien as a libc/msvcrt wrapper:

> luarocks install alien

Then from lua:

require 'alien'

if alien.platform == "windows" then
    -- untested!!
    libc = alien.load("msvcrt.dll")
    libc = alien.default

usleep = libc.usleep
usleep:types('int', 'uint')

function sleep(ms)
    while ms > 1000 do
        ms = ms - 1000
    usleep(1000 * ms)

sleep(500)  -- sleep 500 ms

Caveat lector: I haven't tried this on MSWindows; I don't even know if msvcrt has a usleep()

Difference between session affinity and sticky session?

I've seen those terms used interchangeably, but there are different ways of implementing it:

  1. Send a cookie on the first response and then look for it on subsequent ones. The cookie says which real server to send to.
    Bad if you have to support cookie-less browsers
  2. Partition based on the requester's IP address.
    Bad if it isn't static or if many come in through the same proxy.
  3. If you authenticate users, partition based on user name (it has to be an HTTP supported authentication mode to do this).
  4. Don't require state.
    Let clients hit any server (send state to the client and have them send it back)
    This is not a sticky session, it's a way to avoid having to do it.

I would suspect that sticky might refer to the cookie way, and that affinity might refer to #2 and #3 in some contexts, but that's not how I have seen it used (or use it myself)

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

I got same issue while working with Modal Popup Bootstrap , I used Id and trigger click event for showing and hidding modal popup instead of $("#Id").modal('show') and $("#id").modal('hide'), `

    <button type="button" id="btnPurchaseClose" class="close" data dismiss="modal" aria-label="Close"> <span aria-hidden="true">×</span></button>
<a class="btn btn-default" id="btnOpenPurchasePopup" data-toggle="modal" data target="#newPurchasePopup">Select</a>
    $('#btnPurchaseClose').trigger('click');// for close popup

     $('#btnOpenPurchase').trigger('click');`// for open popup

Getting "type or namespace name could not be found" but everything seems ok?

I was working on VS 2017 community edition and had the same issue with CefSharp nuget packages.

Packages were downloaded and restored successfully, project could be built and run successfully - only the markup indicated that the namespaces were not recognized.

All I had to do was to open the References section and click on one of the yellow exclamation signs.

enter image description here

After a few seconds the markup errors went away.

enter image description here

How to create a function in SQL Server

I can give a small hack, you can use T-SQL function. Try this:

FROM dbo.YourTable .....

Make Error 127 when running trying to compile code

Error 127 means one of two things:

  1. file not found: the path you're using is incorrect. double check that the program is actually in your $PATH, or in this case, the relative path is correct -- remember that the current working directory for a random terminal might not be the same for the IDE you're using. it might be better to just use an absolute path instead.
  2. ldso is not found: you're using a pre-compiled binary and it wants an interpreter that isn't on your system. maybe you're using an x86_64 (64-bit) distro, but the prebuilt is for x86 (32-bit). you can determine whether this is the answer by opening a terminal and attempting to execute it directly. or by running file -L on /bin/sh (to get your default/native format) and on the compiler itself (to see what format it is).

if the problem is (2), then you can solve it in a few diff ways:

  1. get a better binary. talk to the vendor that gave you the toolchain and ask them for one that doesn't suck.
  2. see if your distro can install the multilib set of files. most x86_64 64-bit distros allow you to install x86 32-bit libraries in parallel.
  3. build your own cross-compiler using something like crosstool-ng.
  4. you could switch between an x86_64 & x86 install, but that seems a bit drastic ;).

How can I hide a TD tag using inline JavaScript or CSS?


visibility: hidden


<td class="hide"/>

Edit- Just for you

The difference between display and visibility is this.

"display": has many properties or values, but the ones you're focused on are "none" and "block". "none" is like a hide value, and "block" is like show. If you use the "none" value you will totally hide what ever html tag you have applied this css style. If you use "block" you will see the html tag and it's content. very simple.

"visibility": has many values, but we want to know more about the "hidden" and "visible" values. "hidden" will work in the same way as the "block" value for display, but this will hide tag and it's content, but it will not hide the phisical space of that tag. For example, if you have a couple of text lines, then and image (picture) and then a table with three columns and two rows with icons and text. Now if you apply the visibility css with the hidden value to the image, the image will disappear but the space the image was using will remaing in it's place, in other words, you will end with a big space (hole) between the text and the table. Now if you use the "visible" value your target tag and it's elements will be visible again.

How to convert std::string to LPCSTR?

Converting is simple:

std::string myString;

LPCSTR lpMyString = myString.c_str();

One thing to be careful of here is that c_str does not return a copy of myString, but just a pointer to the character string that std::string wraps. If you want/need a copy you'll need to make one yourself using strcpy.

How to access array elements in a Django template?

You can access sequence elements with arr.0 arr.1 and so on. See The Django template system chapter of the django book for more information.

Eclipse: Java was started but returned error code=13

Since you didn't mention the version of Eclipse, I advice you to download the latest version of Eclipse Luna which comes with Java 8 support by default.

Creating a simple configuration file and parser in C++

Why not trying something simple and human-readable, like JSON (or XML) ?

There are many pre-made open-source implementations of JSON (or XML) for C++ - I would use one of them.

And if you want something more "binary" - try BJSON or BSON :)

Android draw a Horizontal line between views

       android:background="#000000" />

Adjust width of input field to its input

This answer provides one of the most accurate methods of retrieving text width available in the browser and is more accurate than the accepted answer. It uses the canvas html5 element and unlike other answers does not add the element into the DOM and thus avoids any reflow issues caused by excessively adding elements to the DOM.

Read more about the Canvas element here in relation to text width.

NOTE: According to MDN the shorthand versions of the getPropertyValue() method such as font can be unreliable. I'd recommend getting the values singularly to improve compatibility. I only used it here for speed.

 * returns the width of child text of any DOM node as a float_x000D_
function getTextWidth(el) {_x000D_
  // uses a cached canvas if available_x000D_
  var canvas = getTextWidth.canvas || (getTextWidth.canvas = document.createElement("canvas"));_x000D_
  var context = canvas.getContext("2d");_x000D_
  // get the full font style property_x000D_
  var font = window.getComputedStyle(el, null).getPropertyValue('font');_x000D_
  var text = el.value;_x000D_
  // set the font attr for the canvas text_x000D_
  context.font = font;_x000D_
  var textMeasurement = context.measureText(text);_x000D_
  return textMeasurement.width;_x000D_
var input = document.getElementById('myInput');_x000D_
// listen for any input on the input field_x000D_
input.addEventListener('input', function(e) {_x000D_
  var width = Math.floor(getTextWidth(;_x000D_
  // add 10 px to pad the input._x000D_
  var widthInPx = (width + 10) + "px";_x000D_ = widthInPx;_x000D_
}, false);
#myInput {_x000D_
  font: normal normal 400 normal 18px / normal Roboto, sans-serif;_x000D_
  min-width: 40px;_x000D_
<input id="myInput" />

Difference between npx and npm?



Web developers can have dozens of projects on their development machines, and each project has its own particular set of npm-installed dependencies. A few years back, the usual advice for dealing with CLI applications like Grunt or Gulp was to install them locally in each project and also globally so they could easily be run from the command line.

But installing globally caused as many problems as it solved. Projects may depend on different versions of command line tools, and polluting the operating system with lots of development-specific CLI tools isn’t great either. Today, most developers prefer to install tools locally and leave it at that.

Local versions of tools allow developers to pull projects from GitHub without worrying about incompatibilities with globally installed versions of tools. NPM can just install local versions and you’re good to go. But project specific installations aren’t without their problems: how do you run the right version of the tool without specifying its exact location in the project or playing around with aliases?

That’s the problem npx solves. A new tool included in NPM 5.2, npx is a small utility that’s smart enough to run the right application when it’s called from within a project.

If you wanted to run the project-local version of mocha, for example, you can run npx mocha inside the project and it will do what you expect.

A useful side benefit of npx is that it will automatically install npm packages that aren’t already installed. So, as the tool’s creator Kat Marchán points out, you can run npx benny-hill without having to deal with Benny Hill polluting the global environment.

If you want to take npx for a spin, update to the most recent version of npm.

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.

Find unique rows in numpy.array

np.unique works given a list of tuples:

>>> np.unique([(1, 1), (2, 2), (3, 3), (4, 4), (2, 2)])
array([[1, 1],
       [2, 2],
       [3, 3],
       [4, 4]])

With a list of lists it raises a TypeError: unhashable type: 'list'

How to get current SIM card number in Android?

I think sim serial Number and sim number is unique. You can try this for get sim serial number and get sim number and Don't forget to add permission in manifest file.

TelephonyManager telemamanger = (TelephonyManager) getSystemService(Context.TELEPHONY_SERVICE);
String getSimSerialNumber = telemamanger.getSimSerialNumber();
String getSimNumber = telemamanger.getLine1Number();

And add below permission into your Androidmanifest.xml file.

<uses-permission android:name="android.permission.READ_PHONE_STATE"/>

Let me know if there is any issue.

ld cannot find -l<library>

you can add the Path to coinhsl lib to LD_LIBRARY_PATH variable. May be that will help.


where /xx/yy/zz represent the path to coinhsl lib.

How to pass optional arguments to a method in C++?

With commas separating them, just like parameters without default values.

int func( int x = 0, int y = 0 );

func(); // doesn't pass optional parameters, defaults are used, x = 0 and y = 0

func(1, 2); // provides optional parameters, x = 1 and y = 2

possibly undefined macro: AC_MSG_ERROR

i also had similar problem.. my solution is to

apt-get install libcurl4-openssl-dev

(i had libcurl allready installed ) worked for me at least..

How to use workbook.saveas with automatic Overwrite

I recommend that before executing SaveAs, delete the file it exists.

If Dir("f:ull\path\with\filename.xls") <> "" Then
    Kill "f:ull\path\with\filename.xls"
End If

It's easier than setting DisplayAlerts off and on, plus if DisplayAlerts remains off due to code crash, it can cause problems if you work with Excel in the same session.

org.hibernate.StaleStateException: Batch update returned unexpected row count from update [0]; actual row count: 0; expected: 1

its happen when you try to delete the same object and then again update the same object use this after delete


Property 'json' does not exist on type 'Object'

UPDATE: for rxjs > v5.5

As mentioned in some of the comments and other answers, by default the HttpClient deserializes the content of a response into an object. Some of its methods allow passing a generic type argument in order to duck-type the result. Thats why there is no json() method anymore.

import {throwError} from 'rxjs';
import {catchError, map} from 'rxjs/operators';

export interface Order {
  // Properties

interface ResponseOrders {
  results: Order[];

export class FooService {
 ctor(private http: HttpClient){}

 fetch(startIndex: number, limit: number): Observable<Order[]> {
    let params = new HttpParams();
    params = params.set('startIndex',startIndex.toString()).set('limit',limit.toString());
    // base URL should not have ? in it at the en
    return this.http.get<ResponseOrders >(this.baseUrl,{
       map(res => res.results || []),
       catchError(error => _throwError(error.message || error))

Notice that you could easily transform the returned Observable to a Promise by simply invoking toPromise().


In your case, you can

Assumming that your backend returns something like:

{results: [{},{}]}

in JSON format, where every {} is a serialized object, you would need the following:

// Somewhere in your src folder

export interface Order {
  // Properties

import { HttpClient, HttpParams } from '@angular/common/http';
import { Observable } from 'rxjs/Observable';
import 'rxjs/add/operator/catch';
import 'rxjs/add/operator/map';

import { Order } from 'somewhere_in_src';    

export class FooService {
 ctor(private http: HttpClient){}

 fetch(startIndex: number, limit: number): Observable<Order[]> {
    let params = new HttpParams();
    params = params.set('startIndex',startIndex.toString()).set('limit',limit.toString());
    // base URL should not have ? in it at the en
    return this.http.get(this.baseUrl,{
    .map(res => res.results as Order[] || []); 
   // in case that the property results in the res POJO doesnt exist (res.results returns null) then return empty array ([])

I removed the catch section, as this could be archived through a HTTP interceptor. Check the docs. As example:

And to consume you just need to call it like:

// In some component for example
this.fooService.fetch(...).subscribe(data => ...); // data is Order[]

How could I put a border on my grid control in WPF?

This is my solution, wish useful for you:

public class Sheet : Grid
    public static readonly DependencyProperty BorderBrushProperty = DependencyProperty.Register(nameof(BorderBrush), typeof(Brush), typeof(Sheet), new FrameworkPropertyMetadata(Brushes.Transparent, FrameworkPropertyMetadataOptions.AffectsMeasure | FrameworkPropertyMetadataOptions.AffectsRender, OnBorderBrushChanged));

    public static readonly DependencyProperty BorderThicknessProperty = DependencyProperty.Register(nameof(BorderThickness), typeof(double), typeof(Sheet), new FrameworkPropertyMetadata(1D, FrameworkPropertyMetadataOptions.AffectsMeasure | FrameworkPropertyMetadataOptions.AffectsRender, OnBorderThicknessChanged, CoerceBorderThickness));
    public static readonly DependencyProperty CellSpacingProperty = DependencyProperty.Register(nameof(CellSpacing), typeof(double), typeof(Sheet), new FrameworkPropertyMetadata(0D, FrameworkPropertyMetadataOptions.AffectsMeasure | FrameworkPropertyMetadataOptions.AffectsRender, OnCellSpacingChanged, CoerceCellSpacing));

    public Brush BorderBrush
        get => this.GetValue(BorderBrushProperty) as Brush;
        set => this.SetValue(BorderBrushProperty, value);

    public double BorderThickness
        get => (double)this.GetValue(BorderThicknessProperty);
        set => this.SetValue(BorderThicknessProperty, value);

    public double CellSpacing
        get => (double)this.GetValue(CellSpacingProperty);
        set => this.SetValue(CellSpacingProperty, value);

    protected override Size ArrangeOverride(Size arrangeSize)
        Size size = base.ArrangeOverride(arrangeSize);
        double border = this.BorderThickness;
        double doubleBorder = border * 2D;
        double spacing = this.CellSpacing;
        double halfSpacing = spacing * 0.5D;
        if (border > 0D || spacing > 0D)
            foreach (UIElement child in this.InternalChildren)
                this.GetChildBounds(child, out double left, out double top, out double width, out double height);

                left += halfSpacing + border;
                top += halfSpacing + border;
                height -= spacing + doubleBorder;
                width -= spacing + doubleBorder;

                if (width < 0D)
                    width = 0D;

                if (height < 0D)
                    height = 0D;

                left -= left % 0.5D;
                top -= top % 0.5D;
                width -= width % 0.5D;
                height -= height % 0.5D;

                child.Arrange(new Rect(left, top, width, height));

            if (border > 0D && this.BorderBrush != null)

        return size;
    protected override void OnRender(DrawingContext dc)

        if (this.BorderThickness > 0D && this.BorderBrush != null)
            if (this.CellSpacing == 0D)

    private void DrawSeperatedBorder(DrawingContext dc)
        double spacing = this.CellSpacing;
        double halfSpacing = spacing * 0.5D;

        #region draw border
        Pen pen = new Pen(this.BorderBrush, this.BorderThickness);
        UIElementCollection children = this.InternalChildren;
        foreach (UIElement child in children)
            this.GetChildBounds(child, out double left, out double top, out double width, out double height);
            left += halfSpacing;
            top += halfSpacing;
            width -= spacing;
            height -= spacing;

            dc.DrawRectangle(null, pen, new Rect(left, top, width, height));

    private void DrawCollapsedBorder(DrawingContext dc)
        RowDefinitionCollection rows = this.RowDefinitions;
        ColumnDefinitionCollection columns = this.ColumnDefinitions;
        int rowCount = rows.Count;
        int columnCount = columns.Count;
        const byte BORDER_LEFT = 0x08;
        const byte BORDER_TOP = 0x04;
        const byte BORDER_RIGHT = 0x02;
        const byte BORDER_BOTTOM = 0x01;
        byte[,] borderState = new byte[rowCount, columnCount];
        int column = columnCount - 1;
        int columnSpan;
        int row = rowCount - 1;
        int rowSpan;
        #region generate main border data
        for (int i = 0; i < rowCount; i++)
            borderState[i, 0] = BORDER_LEFT;
            borderState[i, column] = BORDER_RIGHT;

        for (int i = 0; i < columnCount; i++)
            borderState[0, i] |= BORDER_TOP;
            borderState[row, i] |= BORDER_BOTTOM;

        #region generate child border data
        UIElementCollection children = this.InternalChildren;
        foreach (UIElement child in children)
            this.GetChildLayout(child, out row, out rowSpan, out column, out columnSpan);
            for (int i = 0; i < rowSpan; i++)
                borderState[row + i, column] |= BORDER_LEFT;
                borderState[row + i, column + columnSpan - 1] |= BORDER_RIGHT;
            for (int i = 0; i < columnSpan; i++)
                borderState[row, column + i] |= BORDER_TOP;
                borderState[row + rowSpan - 1, column + i] |= BORDER_BOTTOM;

        #region draw border
        Pen pen = new Pen(this.BorderBrush, this.BorderThickness);
        double left;
        double top;
        double width, height;

        for (int r = 0; r < rowCount; r++)
            RowDefinition v = rows[r];
            top = v.Offset;
            height = v.ActualHeight;
            for (int c = 0; c < columnCount; c++)
                byte state = borderState[r, c];

                ColumnDefinition h = columns[c];
                left = h.Offset;
                width = h.ActualWidth;
                if ((state & BORDER_LEFT) == BORDER_LEFT)
                    dc.DrawLine(pen, new Point(left, top), new Point(left, top + height));
                if ((state & BORDER_TOP) == BORDER_TOP)
                    dc.DrawLine(pen, new Point(left, top), new Point(left + width, top));
                if ((state & BORDER_RIGHT) == BORDER_RIGHT && (c + 1 >= columnCount || (borderState[r, c + 1] & BORDER_LEFT) == 0))
                    dc.DrawLine(pen, new Point(left + width, top), new Point(left + width, top + height));
                if ((state & BORDER_BOTTOM) == BORDER_BOTTOM && (r + 1 >= rowCount || (borderState[r + 1, c] & BORDER_TOP) == 0))
                    dc.DrawLine(pen, new Point(left, top + height), new Point(left + width, top + height));


    private void GetChildBounds(UIElement child, out double left, out double top, out double width, out double height)
        ColumnDefinitionCollection columns = this.ColumnDefinitions;
        RowDefinitionCollection rows = this.RowDefinitions;
        int rowCount = rows.Count;

        int row = (int)child.GetValue(Grid.RowProperty);
        if (row >= rowCount)
            row = rowCount - 1;

        int rowSpan = (int)child.GetValue(Grid.RowSpanProperty);
        if (row + rowSpan > rowCount)
            rowSpan = rowCount - row;
        int columnCount = columns.Count;

        int column = (int)child.GetValue(Grid.ColumnProperty);
        if (column >= columnCount)
            column = columnCount - 1;

        int columnSpan = (int)child.GetValue(Grid.ColumnSpanProperty);
        if (column + columnSpan > columnCount)
            columnSpan = columnCount - column;

        left = columns[column].Offset;
        top = rows[row].Offset;
        ColumnDefinition right = columns[column + columnSpan - 1];
        width = right.Offset + right.ActualWidth - left;
        RowDefinition bottom = rows[row + rowSpan - 1];
        height = bottom.Offset + bottom.ActualHeight - top;
        if (width < 0D)
            width = 0D;

        if (height < 0D)
            height = 0D;

    private void GetChildLayout(UIElement child, out int row, out int rowSpan, out int column, out int columnSpan)
        int rowCount = this.RowDefinitions.Count;

        row = (int)child.GetValue(Grid.RowProperty);
        if (row >= rowCount)
            row = rowCount - 1;

        rowSpan = (int)child.GetValue(Grid.RowSpanProperty);
        if (row + rowSpan > rowCount)
            rowSpan = rowCount - row;
        int columnCount = this.ColumnDefinitions.Count;

        column = (int)child.GetValue(Grid.ColumnProperty);
        if (column >= columnCount)
            column = columnCount - 1;

        columnSpan = (int)child.GetValue(Grid.ColumnSpanProperty);
        if (column + columnSpan > columnCount)
            columnSpan = columnCount - column;

    private static void OnBorderBrushChanged(DependencyObject d, DependencyPropertyChangedEventArgs args)
        if (d is UIElement element)

    private static void OnBorderThicknessChanged(DependencyObject d, DependencyPropertyChangedEventArgs args)
        if (d is UIElement element)

    private static void OnCellSpacingChanged(DependencyObject d, DependencyPropertyChangedEventArgs args)
        if (d is UIElement element)

    private static object CoerceBorderThickness(DependencyObject d, object baseValue)
        if (baseValue is double value)
            return value < 0D || double.IsNaN(value) || double.IsInfinity(value) ? 0D : value;

        return 0D;
    private static object CoerceCellSpacing(DependencyObject d, object baseValue)
        if (baseValue is double value)
            return value < 0D || double.IsNaN(value) || double.IsInfinity(value) ? 0D : value;

        return 0D;

a demo: demo of a table with collapsed border

JS strings "+" vs concat method

MDN has the following to say about string.concat():

It is strongly recommended to use the string concatenation operators (+, +=) instead of this method for perfomance reasons

Also see the link by @Bergi.

jQuery animated number counter from zero to value

You can get the element itself in .each(), try this instead of using this

$('.Count').each(function (index, value) {
    jQuery({ Counter: 0 }).animate({ Counter: value.text() }, {
        duration: 1000,
        easing: 'swing',
        step: function () {

Rounded table corners CSS only

Seems to work fine in FF and Chrome (haven't tested any others) with separate borders:

Edit: Here's a relatively clean implementation of your sketch:

table {_x000D_
    border:solid black 1px;_x000D_
td, th {_x000D_
    border-left:solid black 1px;_x000D_
    border-top:solid black 1px;_x000D_
th {_x000D_
    background-color: blue;_x000D_
    border-top: none;_x000D_
td:first-child, th:first-child {_x000D_
     border-left: none;_x000D_

MVC 4 Edit modal form using Bootstrap

In reply to Dimitrys answer but using Ajax.BeginForm the following works at least with MVC >5 (4 not tested).

  1. write a model as shown in the other answers,

  2. In the "parent view" you will probably use a table to show the data. Model should be an ienumerable. I assume, the model has an id-property. Howeverm below the template, a placeholder for the modal and corresponding javascript

    @foreach (var item in Model)
        <tr> <td id="[email protected]"> 
            @Html.Partial("dataRowView", item)
        </td> </tr>
    <div class="modal fade" id="editor-container" tabindex="-1" 
         role="dialog" aria-labelledby="editor-title">
        <div class="modal-dialog modal-lg" role="document">
            <div class="modal-content" id="editor-content-container"></div>
    <script type="text/javascript">
        $(function () {
            $('.editor-container').click(function () {
                var url = "/area/controller/MyEditAction";  
                var id = $(this).attr('data-id');  
                $.get(url + '/' + id, function (data) {
        function success(data,status,xhr) {
        function failure(xhr,status,error) {

note the "editor-success-id" in data table rows.

  1. The dataRowView is a partial containing the presentation of an model's item.

    @model ModelView
        var item = Model;
    <div class="row">
            // some data 
            <button type="button" class="btn btn-danger editor-container" data-id="@item.Id">Edit</button>
  2. Write the partial view that is called by clicking on row's button (via JS $('.editor-container').click(function () ... ).

    @model Model
    <div class="modal-header">
        <button type="button" class="close" data-dismiss="modal" aria-label="Close">
            <span aria-hidden="true">&times;</span>
        <h4 class="modal-title" id="editor-title">Title</h4>
    @using (Ajax.BeginForm("MyEditAction", "Controller", FormMethod.Post,
                        new AjaxOptions
                            InsertionMode = InsertionMode.Replace,
                            HttpMethod = "POST",
                            UpdateTargetId = "editor-success-" + @Model.Id,
                            OnSuccess = "success",
                            OnFailure = "failure",
        @Html.HiddenFor(model => model.Id)
        <div class="modal-body">
            <div class="form-horizontal">
                // Models input fields
        <div class="modal-footer">
            <button type="button" class="btn btn-default" data-dismiss="modal">Cancel</button>
            <button type="submit" class="btn btn-primary">Save</button>

This is where magic happens: in AjaxOptions, UpdateTargetId will replace the data row after editing, onfailure and onsuccess will control the modal.

This is, the modal will only close when editing was successful and there have been no errors, otherwise the modal will be displayed after the ajax-posting to display error messages, e.g. the validation summary.

But how to get ajaxform to know if there is an error? This is the controller part, just change response.statuscode as below in step 5:

  1. the corresponding controller action method for the partial edit modal

    public async Task<ActionResult> EditPartData(Guid? id)
        // Find the data row and return the edit form
        Model input = await db.Models.FindAsync(id);
        return PartialView("EditModel", input);
    [HttpPost, ValidateAntiForgeryToken]
    public async Task<ActionResult> MyEditAction([Bind(Include =
       "Id,Fields,...")] ModelView input)
        if (TryValidateModel(input))
            // save changes, return new data row  
            // status code is something in 200-range
            db.Entry(input).State = EntityState.Modified;
            await db.SaveChangesAsync();
            return PartialView("dataRowView", (ModelView)input);
        // set the "error status code" that will redisplay the modal
        Response.StatusCode = 400;
        // and return the edit form, that will be displayed as a 
        // modal again - including the modelstate errors!
        return PartialView("EditModel", (Model)input);

This way, if an error occurs while editing Model data in a modal window, the error will be displayed in the modal with validationsummary methods of MVC; but if changes were committed successfully, the modified data table will be displayed and the modal window disappears.

Note: you get ajaxoptions working, you need to tell your bundles configuration to bind jquery.unobtrusive-ajax.js (may be installed by NuGet):

        bundles.Add(new ScriptBundle("~/bundles/jqueryajax").Include(


PYTHONPATH is an environment variable those content is added to the sys.path where Python looks for modules. You can set it to whatever you like.

However, do not mess with PYTHONPATH. More often than not, you are doing it wrong and it will only bring you trouble in the long run. For example, virtual environments could do strange things…

I would suggest you learned how to package a Python module properly, maybe using this easy setup. If you are especially lazy, you could use cookiecutter to do all the hard work for you.

Set order of columns in pandas dataframe

You can also use OrderedDict:

In [183]: from collections import OrderedDict

In [184]: data = OrderedDict()

In [185]: data['one thing'] = [1,2,3,4]

In [186]: data['second thing'] = [0.1,0.2,1,2]

In [187]: data['other thing'] = ['a','e','i','o']

In [188]: frame = pd.DataFrame(data)

In [189]: frame
   one thing  second thing other thing
0          1           0.1           a
1          2           0.2           e
2          3           1.0           i
3          4           2.0           o

Loading an image to a <img> from <input file>

$('document').ready(function () {
    $("#imgload").change(function () {
        if (this.files && this.files[0]) {
            var reader = new FileReader();
            reader.onload = function (e) {
<script src=""></script>
<input type="file" id="imgload" >
<img src="#" id="imgshow" align="left">

That works for me in jQuery.

WPF Application that only has a tray icon

I recently had this same problem. Unfortunately, NotifyIcon is only a Windows.Forms control at the moment, if you want to use it you are going to have to include that part of the framework. I guess that depends how much of a WPF purist you are.

If you want a quick and easy way of getting started check out this WPF NotifyIcon control on the Code Project which does not rely on the WinForms NotifyIcon at all. A more recent version seems to be available on the author's website and as a NuGet package. This seems like the best and cleanest way to me so far.

  • Rich ToolTips rather than text
  • WPF context menus and popups
  • Command support and routed events
  • Flexible data binding
  • Rich balloon messages rather than the default messages provides by the OS

Check it out. It comes with an amazing sample app too, very easy to use, and you can have great looking Windows Live Messenger style WPF popups, tooltips, and context menus. Perfect for displaying an RSS feed, I am using it for a similar purpose.

Get controller and action name from within controller?

This seems to work nicely for me (so far), also works if you are using attribute routing.

public class BaseController : Controller
    protected string CurrentAction { get; private set; }
    protected string CurrentController { get; private set; }

    protected override void Initialize(RequestContext requestContext)

    private void PopulateControllerActionInfo(RequestContext requestContext)
        RouteData routedata = requestContext.RouteData;

        object routes;

        if (routedata.Values.TryGetValue("MS_DirectRouteMatches", out routes))
            routedata = (routes as List<RouteData>)?.FirstOrDefault();

        if (routedata == null)

        Func<string, string> getValue = (s) =>
            object o;
            return routedata.Values.TryGetValue(s, out o) ? o.ToString() : String.Empty;

        this.CurrentAction = getValue("action");
        this.CurrentController = getValue("controller");

Warning: mysqli_error() expects exactly 1 parameter, 0 given error


die (mysqli_error()); 


die('Error: ' . mysqli_error($myConnection));

in the query

$query = mysqli_query($myConnection, $sqlCommand) or die (mysqli_error()); 

Laravel 5.2 redirect back with success message

You should remove web middleware from routes.php. Adding web middleware manually causes session and request related problems in Laravel 5.2.27 and higher.

If it didn't help (still, keep routes.php without web middleware), you can try little bit different approach:

return redirect()->back()->with('message', 'IT WORKS!');

Displaying message if it exists:

    <div class="alert alert-success">
        {{ session()->get('message') }}