Programs & Examples On #Scope chain

How do I get ASP.NET Web API to return JSON instead of XML using Chrome?

You can use as below:

GlobalConfiguration.Configuration.Formatters.Add(new JsonMediaTypeFormatter());

Stop absolutely positioned div from overlapping text

Could you add z-index style to the two sections so that the one you want appears on top?

Maximum value for long integer

Unlike C/C++ Long in Python have unlimited precision. Refer the section Numeric Types in python for more information.To determine the max value of integer you can just refer sys.maxint. You can get more details from the documentation of sys.

Get connection status on client

Track the state of the connection yourself. With a boolean. Set it to false at declaration. Use the various events (connect, disconnect, reconnect, etc.) to reassign the current boolean value. Note: Using undocumented API features (e.g., socket.connected), is not a good idea; the feature could get removed in a subsequent version without the removal being mentioned.

How to remove newlines from beginning and end of a string?

If you only want to remove line breaks (not spaces, tabs) at the beginning and end of a String (not inbetween), then you can use this approach:

Use a regular expressions to remove carriage returns (\\r) and line feeds (\\n) from the beginning (^) and ending ($) of a string:

 s = s.replaceAll("(^[\\r\\n]+|[\\r\\n]+$)", "")

Complete Example:

public class RemoveLineBreaks {
    public static void main(String[] args) {
        var s = "\nHello\nWorld\n";
        System.out.println("before: >"+s+"<");
        s = s.replaceAll("(^[\\r\\n]+|[\\r\\n]+$)", "");
        System.out.println("after: >"+s+"<");

It outputs:

before: >
after: >Hello

What is the difference between git clone and checkout?

One thing to notice is the lack of any "Copyout" within git. That's because you already have a full copy in your local repo - your local repo being a clone of your chosen upstream repo. So you have effectively a personal checkout of everything, without putting some 'lock' on those files in the reference repo.

Git provides the SHA1 hash values as the mechanism for verifying that the copy you have of a file / directory tree / commit / repo is exactly the same as that used by whoever is able to declare things as "Master" within the hierarchy of trust. This avoids all those 'locks' that cause most SCM systems to choke (with the usual problems of private copies, big merges, and no real control or management of source code ;-) !

How to use the "required" attribute with a "radio" input field

I had to use required="required" along with the same name and type, and then validation worked fine.

<input type="radio" name="user-radio"  id="" value="User" required="required" />

<input type="radio" name="user-radio" id="" value="Admin" />

<input type="radio" name="user-radio" id="" value="Guest" /> 

The Android emulator is not starting, showing "invalid command-line parameter"

I had the same problem. I made it work with:

"C:\Program Files (x86)\Android\android-sdk\tools\emulator-arm.exe"  @foo

foo is the name of your virtual device.

How do you test to see if a double is equal to NaN?

Beginners needs practical examples. so try the following code.

public class Not_a_Number {

public static void main(String[] args) {
    // TODO Auto-generated method stub

    String message = "0.0/0.0 is NaN.\nsimilarly Math.sqrt(-1) is NaN.";        
    String dottedLine = "------------------------------------------------";     

    Double numerator = -2.0;
    Double denominator = -2.0;      
    while (denominator <= 1) {
        Double x = numerator/denominator;           
        Double y = new Double (x);
        boolean z = y.isNaN();
        System.out.println("y =  " + y);
        System.out.println("z =  " + z);
        if (z == true){
        else {
            System.out.println("Hi, everyone"); 
        numerator = numerator + 1;
        denominator = denominator +1;
    } // end of while

} // end of main

} // end of class

How to know if a DateTime is between a DateRange in C#

You could use extension methods to make it a little more readable:

public static class DateTimeExtensions
    public static bool InRange(this DateTime dateToCheck, DateTime startDate, DateTime endDate)
        return dateToCheck >= startDate && dateToCheck < endDate;

Now you can write:

dateToCheck.InRange(startDate, endDate)

How to Inspect Element using Safari Browser

in menu bar click on Edit->preference->advance at bottom click the check box true that is for Show develop menu in menu bar now a develop menu is display at menu bar where you can see all develop option and inspect.

Selecting specific rows and columns from NumPy array


 >>> a[[0,1,3]][:,[0,2]]
array([[ 0,  2],
   [ 4,  6],
   [12, 14]])


>>> a[[0,1,3],::2]
array([[ 0,  2],
   [ 4,  6],
   [12, 14]])

How to import a csv file using python with headers intact, where first column is a non-numerical

For Python 3

Remove the rb argument and use either r or don't pass argument (default read mode).

with open( <path-to-file>, 'r' ) as theFile:
    reader = csv.DictReader(theFile)
    for line in reader:
        # line is { 'workers': 'w0', 'constant': 7.334, 'age': -1.406, ... }
        # e.g. print( line[ 'workers' ] ) yields 'w0'

For Python 2

import csv
with open( <path-to-file>, "rb" ) as theFile:
    reader = csv.DictReader( theFile )
    for line in reader:
        # line is { 'workers': 'w0', 'constant': 7.334, 'age': -1.406, ... }
        # e.g. print( line[ 'workers' ] ) yields 'w0'

Python has a powerful built-in CSV handler. In fact, most things are already built in to the standard library.

How can I get sin, cos, and tan to use degrees instead of radians?

I like a more general functional approach:

* converts a trig function taking radians to degrees
* @param {function} trigFunc - eg. Math.cos, Math.sin, etc.
* @param {number} angle - in degrees
* @returns {number}
const dTrig = (trigFunc, angle) => trigFunc(angle * Math.PI / 180);


function dTrig(trigFunc, angle) {
  return trigFunc(angle * Math.PI / 180);

which can be used with any radian-taking function:

dTrig(Math.sin, 90);
  // -> 1

dTrig(Math.tan, 180);
  // -> 0

Hope this helps!

RegEx for validating an integer with a maximum length of 10 characters

0123456789 is not a valid integer (usually zeros will be stripped)

I think something like this regexp would be better to use:


(does not support signed numbers)

JavaScript - document.getElementByID with onClick

Perhaps you might want to use "addEventListener"

document.getElementById("test").addEventListener('click',function ()
   }  ); 

Hope it's still useful for you

How do I remove accents from characters in a PHP string?

You can use an array key => value style to use with strtr() safely for UTF-8 characters even if they are multi-bytes.

function no_accent($str){
    $accents = array('À' => 'A', 'Á' => 'A', 'Â' => 'A', 'Ã' => 'A', 'Ä' => 'A', 'Å' => 'A', 'à' => 'a', 'á' => 'a', 'â' => 'a', 'ã' => 'a', 'ä' => 'a', 'å' => 'a', 'A' => 'A', 'a' => 'a', 'A' => 'A', 'a' => 'a', 'A' => 'A', 'a' => 'a', 'Ç' => 'C', 'ç' => 'c', 'C' => 'C', 'c' => 'c', 'C' => 'C', 'c' => 'c', 'C' => 'C', 'c' => 'c', 'C' => 'C', 'c' => 'c', 'Ð' => 'D', 'ð' => 'd', 'D' => 'D', 'd' => 'd', 'Ð' => 'D', 'd' => 'd', 'È' => 'E', 'É' => 'E', 'Ê' => 'E', 'Ë' => 'E', 'è' => 'e', 'é' => 'e', 'ê' => 'e', 'ë' => 'e', 'E' => 'E', 'e' => 'e', 'E' => 'E', 'e' => 'e', 'E' => 'E', 'e' => 'e', 'E' => 'E', 'e' => 'e', 'E' => 'E', 'e' => 'e', 'G' => 'G', 'g' => 'g', 'G' => 'G', 'g' => 'g', 'G' => 'G', 'g' => 'g', 'G' => 'G', 'g' => 'g', 'H' => 'H', 'h' => 'h', 'H' => 'H', 'h' => 'h', 'Ì' => 'I', 'Í' => 'I', 'Î' => 'I', 'Ï' => 'I', 'ì' => 'i', 'í' => 'i', 'î' => 'i', 'ï' => 'i', 'I' => 'I', 'i' => 'i', 'I' => 'I', 'i' => 'i', 'I' => 'I', 'i' => 'i', 'I' => 'I', 'i' => 'i', 'I' => 'I', 'i' => 'i', 'J' => 'J', 'j' => 'j', 'K' => 'K', 'k' => 'k', '?' => 'k', 'L' => 'L', 'l' => 'l', 'L' => 'L', 'l' => 'l', 'L' => 'L', 'l' => 'l', '?' => 'L', '?' => 'l', 'L' => 'L', 'l' => 'l', 'Ñ' => 'N', 'ñ' => 'n', 'N' => 'N', 'n' => 'n', 'N' => 'N', 'n' => 'n', 'N' => 'N', 'n' => 'n', '?' => 'n', '?' => 'N', '?' => 'n', 'Ò' => 'O', 'Ó' => 'O', 'Ô' => 'O', 'Õ' => 'O', 'Ö' => 'O', 'Ø' => 'O', 'ò' => 'o', 'ó' => 'o', 'ô' => 'o', 'õ' => 'o', 'ö' => 'o', 'ø' => 'o', 'O' => 'O', 'o' => 'o', 'O' => 'O', 'o' => 'o', 'O' => 'O', 'o' => 'o', 'R' => 'R', 'r' => 'r', 'R' => 'R', 'r' => 'r', 'R' => 'R', 'r' => 'r', 'S' => 'S', 's' => 's', 'S' => 'S', 's' => 's', 'S' => 'S', 's' => 's', 'Š' => 'S', 'š' => 's', '?' => 's', 'T' => 'T', 't' => 't', 'T' => 'T', 't' => 't', 'T' => 'T', 't' => 't', 'Ù' => 'U', 'Ú' => 'U', 'Û' => 'U', 'Ü' => 'U', 'ù' => 'u', 'ú' => 'u', 'û' => 'u', 'ü' => 'u', 'U' => 'U', 'u' => 'u', 'U' => 'U', 'u' => 'u', 'U' => 'U', 'u' => 'u', 'U' => 'U', 'u' => 'u', 'U' => 'U', 'u' => 'u', 'U' => 'U', 'u' => 'u', 'W' => 'W', 'w' => 'w', 'Ý' => 'Y', 'ý' => 'y', 'ÿ' => 'y', 'Y' => 'Y', 'y' => 'y', 'Ÿ' => 'Y', 'Z' => 'Z', 'z' => 'z', 'Z' => 'Z', 'z' => 'z', 'Ž' => 'Z', 'ž' => 'z');
    return strtr($str, $accents);

Plus, you save decode/encode in UTF-8 part.

How to load external webpage in WebView


<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android=""
        app:layout_constraintTop_toTopOf="parent" />


package com.example.myapplication;


import android.os.Bundle;
import android.webkit.WebView;
import android.webkit.WebViewClient;

public class MainActivity extends AppCompatActivity {
    private class MyWebViewClient extends WebViewClient {
        public boolean shouldOverrideUrlLoading(WebView view, String url) {
            return true;
    WebView webView;
    protected void onCreate(Bundle savedInstanceState) {

        webView = findViewById(;
        webView .loadUrl("");
        webView.setWebViewClient(new MyWebViewClient());

AndroidManifest.xml: (add uses-permission and android:usesCleartextTraffic)

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android=""

    <uses-permission android:name="android.permission.INTERNET" />

        <activity android:name=".MainActivity">
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />


move column in pandas dataframe

Simple solution:

old_cols = df.columns.values 
new_cols= ['a', 'y', 'b', 'x']
df = df.reindex(columns=new_cols)

How to uninstall mini conda? python

If you are using windows, just search for miniconda and you'll find the folder. Go into the folder and you'll find a miniconda uninstall exe file. Run it.

How to set a Javascript object values dynamically?

You could also create something that would be similar to a value object (vo);


function SomeModelClassNameVO(name,id) { = name; = id;

Than you can just do;

   var someModelClassNameVO = new someModelClassNameVO('name',1);

What underlies this JavaScript idiom: var self = this?

As mentioned several times above, 'self' is simply being used to keep a reference to 'this' prior to entering the funcition. Once in the function 'this' refers to something else.

How to switch activity without animation in Android?

Here is a one-liner solution that works for as low as minSdkVersion 14 which you should insert in you res/styles.xml:

<item name="android:windowAnimationStyle">@null</item>

like so:

    <!-- Base application theme. -->
    <style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">
        <item name="android:windowAnimationStyle">@null</item>


Convert .pem to .crt and .key

If you asked this question because you're using mkcert then the trick is that the .pem file is the cert and the -key.pem file is the key.

(You don't need to convert, just run mkcert )

How to get JSON Key and Value?

$.each(result, function(key, value) {
  console.log(key+ ':' + value);

PHP cURL error code 60

First you have to download the certificate from this link

and put it in a location you want the name of downloadable file is : cacert.pem So in my case I will put it under C:\wamp64\bin\php\cacert.pem

Then you have to specify the location of the php.ini file

For example, I am using php 7 the php.ini file is located at : C:\wamp64\bin\php\php7.0.10\php.ini

So access to that file and uncommit this line ;openssl.cafile

also update it to be looks like this openssl.cafile="C:\wamp64\bin\php\cacert.pem"

Finally restart your apache server and that's all

Table and Index size in SQL Server

On SQL 2012 getting this information on a table level has become deliciously simple:

SQL Management Studio -> Right click on Db -> Reports -> Standard Reports -> Disk usage by table !


Current time formatting with Javascript

A JavaScript Date has several methods allowing you to extract its parts:

getFullYear() - Returns the 4-digit year
getMonth() - Returns a zero-based integer (0-11) representing the month of the year.
getDate() - Returns the day of the month (1-31).
getDay() - Returns the day of the week (0-6). 0 is Sunday, 6 is Saturday.
getHours() - Returns the hour of the day (0-23).
getMinutes() - Returns the minute (0-59).
getSeconds() - Returns the second (0-59).
getMilliseconds() - Returns the milliseconds (0-999).
getTimezoneOffset() - Returns the number of minutes between the machine local time and UTC.

There are no built-in methods allowing you to get localized strings like "Friday", "February", or "PM". You have to code that yourself. To get the string you want, you at least need to store string representations of days and months:

var months = ["Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"];
var days = ["Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"];

Then, put it together using the methods above:

var months = ["Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"];_x000D_
var days = ["Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"];_x000D_
var d = new Date();_x000D_
var day = days[d.getDay()];_x000D_
var hr = d.getHours();_x000D_
var min = d.getMinutes();_x000D_
if (min < 10) {_x000D_
    min = "0" + min;_x000D_
var ampm = "am";_x000D_
if( hr > 12 ) {_x000D_
    hr -= 12;_x000D_
    ampm = "pm";_x000D_
var date = d.getDate();_x000D_
var month = months[d.getMonth()];_x000D_
var year = d.getFullYear();_x000D_
var x = document.getElementById("time");_x000D_
x.innerHTML = day + " " + hr + ":" + min + ampm + " " + date + " " + month + " " + year;
<span id="time"></span>

I have a date format function I like to include in my standard library. It takes a format string parameter that defines the desired output. The format strings are loosely based on .Net custom Date and Time format strings. For the format you specified the following format string would work: "dddd h:mmtt d MMM yyyy".

var d = new Date();
var x = document.getElementById("time");
x.innerHTML = formatDate(d, "dddd h:mmtt d MMM yyyy");


Here is my full date formatting function:

function formatDate(date, format, utc) {
    var MMMM = ["\x00", "January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"];
    var MMM = ["\x01", "Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"];
    var dddd = ["\x02", "Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"];
    var ddd = ["\x03", "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"];

    function ii(i, len) {
        var s = i + "";
        len = len || 2;
        while (s.length < len) s = "0" + s;
        return s;

    var y = utc ? date.getUTCFullYear() : date.getFullYear();
    format = format.replace(/(^|[^\\])yyyy+/g, "$1" + y);
    format = format.replace(/(^|[^\\])yy/g, "$1" + y.toString().substr(2, 2));
    format = format.replace(/(^|[^\\])y/g, "$1" + y);

    var M = (utc ? date.getUTCMonth() : date.getMonth()) + 1;
    format = format.replace(/(^|[^\\])MMMM+/g, "$1" + MMMM[0]);
    format = format.replace(/(^|[^\\])MMM/g, "$1" + MMM[0]);
    format = format.replace(/(^|[^\\])MM/g, "$1" + ii(M));
    format = format.replace(/(^|[^\\])M/g, "$1" + M);

    var d = utc ? date.getUTCDate() : date.getDate();
    format = format.replace(/(^|[^\\])dddd+/g, "$1" + dddd[0]);
    format = format.replace(/(^|[^\\])ddd/g, "$1" + ddd[0]);
    format = format.replace(/(^|[^\\])dd/g, "$1" + ii(d));
    format = format.replace(/(^|[^\\])d/g, "$1" + d);

    var H = utc ? date.getUTCHours() : date.getHours();
    format = format.replace(/(^|[^\\])HH+/g, "$1" + ii(H));
    format = format.replace(/(^|[^\\])H/g, "$1" + H);

    var h = H > 12 ? H - 12 : H == 0 ? 12 : H;
    format = format.replace(/(^|[^\\])hh+/g, "$1" + ii(h));
    format = format.replace(/(^|[^\\])h/g, "$1" + h);

    var m = utc ? date.getUTCMinutes() : date.getMinutes();
    format = format.replace(/(^|[^\\])mm+/g, "$1" + ii(m));
    format = format.replace(/(^|[^\\])m/g, "$1" + m);

    var s = utc ? date.getUTCSeconds() : date.getSeconds();
    format = format.replace(/(^|[^\\])ss+/g, "$1" + ii(s));
    format = format.replace(/(^|[^\\])s/g, "$1" + s);

    var f = utc ? date.getUTCMilliseconds() : date.getMilliseconds();
    format = format.replace(/(^|[^\\])fff+/g, "$1" + ii(f, 3));
    f = Math.round(f / 10);
    format = format.replace(/(^|[^\\])ff/g, "$1" + ii(f));
    f = Math.round(f / 10);
    format = format.replace(/(^|[^\\])f/g, "$1" + f);

    var T = H < 12 ? "AM" : "PM";
    format = format.replace(/(^|[^\\])TT+/g, "$1" + T);
    format = format.replace(/(^|[^\\])T/g, "$1" + T.charAt(0));

    var t = T.toLowerCase();
    format = format.replace(/(^|[^\\])tt+/g, "$1" + t);
    format = format.replace(/(^|[^\\])t/g, "$1" + t.charAt(0));

    var tz = -date.getTimezoneOffset();
    var K = utc || !tz ? "Z" : tz > 0 ? "+" : "-";
    if (!utc) {
        tz = Math.abs(tz);
        var tzHrs = Math.floor(tz / 60);
        var tzMin = tz % 60;
        K += ii(tzHrs) + ":" + ii(tzMin);
    format = format.replace(/(^|[^\\])K/g, "$1" + K);

    var day = (utc ? date.getUTCDay() : date.getDay()) + 1;
    format = format.replace(new RegExp(dddd[0], "g"), dddd[day]);
    format = format.replace(new RegExp(ddd[0], "g"), ddd[day]);

    format = format.replace(new RegExp(MMMM[0], "g"), MMMM[M]);
    format = format.replace(new RegExp(MMM[0], "g"), MMM[M]);

    format = format.replace(/\\(.)/g, "$1");

    return format;

How to select all instances of selected region in Sublime Text

In the other posts, you have the shortcut keys, but if you want the menu option in every system, just go to Find > Quick Find All, as shown in the image attached.

Also, check the other answers for key binding to do it faster than menu clicking.

Sublime Text 3

Why is json_encode adding backslashes?

This happens because the JSON format uses ""(Quotes) and anything in between these quotes is useful information (either key or the data).

Suppose your data was : He said "This is how it is done". Then the actual data should look like "He said \"This is how it is done\".".

This ensures that the \" is treated as "(Quotation mark) and not as JSON formatting. This is called escape character.

This usually happens when one tries to encode an already JSON encoded data, which is a common way I have seen this happen.

Try this

$arr = ['This is a sample','This is also a "sample"']; echo json_encode($arr);


["This is a sample","This is also a \"sample\""]

Converting json results to a date

You need to extract the number from the string, and pass it into the Date constructor:

var x = [{
    "id": 1,
    "start": "\/Date(1238540400000)\/"
}, {
    "id": 2,
    "start": "\/Date(1238626800000)\/"

var myDate = new Date(x[0].start.match(/\d+/)[0] * 1);

The parts are:

x[0].start                                - get the string from the JSON
x[0].start.match(/\d+/)[0]                - extract the numeric part
x[0].start.match(/\d+/)[0] * 1            - convert it to a numeric type
new Date(x[0].start.match(/\d+/)[0] * 1)) - Create a date object

Apache 2.4.3 (with XAMPP 1.8.1) not starting in windows 8

So here is the solution for this:

I check port 80 used by Skype, after that I changes port to 81 and also along with that somewhere i read this error may be because of SSL Port then I changed SSL port to 444. However this got resolved easily.

One most important thing to notice here, all the port changes should be done inside config files, for http port change: httpd.conf for SSL httpd-ssl.conf. Otherwise changes will not replicate to Apache, Sometime PC reboot is also required.

Edit: Make Apache use port 80 and make Skype communicate on other Port

For those who are struggling with Skype, want to change its port and to make Apache to use port 80.

No need to Re-Install, Here is simply how to change Skype Port

Goto: Tools > Options > Advanced > Connection

There you need to uncheck Use port 80 and 443 as alternative for incoming connections.

That's it, here is screen shot of it.

Changing Skype Port

How do you round a double in Dart to a given degree of precision AFTER the decimal point?

If you don't want any decimals when the resulting decimals are all zeroes, something like this would work:

String fixedDecimals(double d, int decimals, {bool removeZeroDecimals = true}){
  double mod = pow(10.0, decimals);
  double result = ((d * mod).round().toDouble() / mod);
  if( removeZeroDecimals && result - (result.truncate()) == 0.0 ) decimals = 0;
  return result.toStringAsFixed(decimals);

This will simply output 9 instead of 9.00 if the input is 9.004 and you want 2 decimals.

How to print variables without spaces between values

To build off what Martjin was saying. I'd use string interpolation/formatting.

In Python 2.x which seems to be what you're using due to the lack of parenthesis around the print function you do:

print 'Value is "%d"' % value

In Python 3.x you'd use the format method instead, so you're code would look like this.

message = 'Value is "{}"'

jQuery input button click event listener

First thing first, button() is a jQuery ui function to create a button widget which has nothing to do with jQuery core, it just styles the button.
So if you want to use the widget add jQuery ui's javascript and CSS files or alternatively remove it, like this:


Another thing that might have caused you the problem is if you didn't wait for the input to be rendered and wrote the code before the input. jQuery has the ready function, or it's alias $(func) which execute the callback once the DOM is ready.


So even if the order is this it will work:


<input type="button" id="filter" name="filter" value="Filter" />


Should C# or C++ be chosen for learning Games Programming (consoles)?

C++, for two reasons.

1) a lot of games are programmed in C++. No mainstream game is, as yet, programmed in a managed language.

2) C++ is as hard as it gets. You have to master manual memory management and generally no bounds checking (beyond the excellent Valgrind!). If you master C++, you will find this transferable to managed procedural languages. Less so the other way around.

C++ has a level of complexity close to APL! You'll never get better by playing weaker opponents.

Joel makes a very strong point about this. People who understand how the machine works make better programmers, because all abstractions are leaky.

CSS fixed width in a span

Using HTML 5.0, it is possible to fix width of text block using <span> or <div>.

enter image description here

For <span>, what is important is to add following CCS line

display: inline-block;

For your empty <span> what is important is to add &nbsp; space.

My code is following

 font-family: Arial;_x000D_
 background-color: lime;_x000D_
div span_x000D_
 background-color: lime;_x000D_
ul li span_x000D_
 display: inline-block;_x000D_
 width: 80px;_x000D_
 background-color: yellow;_x000D_
 display: inline-block;_x000D_
 width: 80px;_x000D_
 background-color: yellow;_x000D_
<div class='test'>ABCDEF</div>_x000D_
    <span class='test'>ABCDEF</span>_x000D_
  <li><span class='tab'>&nbsp;</span> The lazy dog.</li>_x000D_
  <li><span class='tab'>AND</span> The lazy cat.</li>_x000D_
  <li><span class='tab'>OR</span> The active goldfish.</li>_x000D_

PS: I have defined tab class because ul li span CSS selector is not working on my PC !

collapse cell in jupyter notebook

There are many answers to this question, all of which I feel are not satisfactory (some more than others), of the many extensions - code folding, folding by headings etc etc. None do what I want in simple and effective way. I am literally amazed that a solution has not been implemented (as it has for Jupyter Lab).

In fact, I was so dissatisfied that I have developed a very simple notebook extension that can expand/collapse the code in a notebook cell, while keeping it executable.

The GitHub repository:

Below is a small demo of what the extension does:

Simply double clicking left of the code cell will collapse it to a single line:

Double clicking again will expand the cell.

The extension can be installed easily with pip:

pip install nbextension-cellfolding
jupyter nbextension install --py cellfolding --user
jupyter nbextension enable --py cellfolding --user 

and is also compatible with nbextension configurator. I hope that people will find this useful!

jQuery - disable selected options

Add this line to your change event handler

    $("#theSelect option:selected").attr('disabled','disabled')

This will disable the selected option, and enable any previously disabled options.


If you did not want to re-enable the previous ones, just remove this part of the line:



To re-enable when you click remove, add this to your click handler.

$("#theSelect option[value=" + value + "]").removeAttr('disabled');

Deserialize JSON to ArrayList<POJO> using Jackson

You can deserialize directly to a list by using the TypeReference wrapper. An example method:

public static <T> T fromJSON(final TypeReference<T> type,
      final String jsonPacket) {
   T data = null;

   try {
      data = new ObjectMapper().readValue(jsonPacket, type);
   } catch (Exception e) {
      // Handle the problem
   return data;

And is used thus:

final String json = "";
Set<POJO> properties = fromJSON(new TypeReference<Set<POJO>>() {}, json);

TypeReference Javadoc

PostgreSQL 'NOT IN' and subquery

When using NOT IN you should ensure that none of the values are NULL:

SELECT mac, creation_date 
FROM logs 
WHERE logs_type_id=11
AND mac NOT IN (
    SELECT mac
    FROM consols
    WHERE mac IS NOT NULL -- add this

Restful API service

I know @Martyn does not want full code, but I think this annotation its good for this question:

10 Open Source Android Apps which every Android developer must look into

Foursquared for Android is open-source, and have an interesting code pattern interacting with the foursquare REST API.

IIS_IUSRS and IUSR permissions in IIS8

I would use specific user (and NOT Application user). Then I will enable impersonation in the application. Once you do that whatever account is set as the specific user, those credentials would used to access local resources on that server (Not for external resources).

Specific User setting is specifically meant for accessing local resources.

Rendering HTML inside textarea

I have the same problem but in reverse, and the following solution. I want to put html from a div in a textarea (so I can edit some reactions on my website; I want to have the textarea in the same location.)

To put the content of this div in a textarea I use:

var content = $('#msg500').text();_x000D_
$('#msg500').wrapInner('<textarea>' + content + '</textarea>');
<script src=""></script>_x000D_
<div id="msg500">here some <strong>html</strong> <i>tags</i>.</div>

String.Format not work in TypeScript

You can use TypeScript's native string interpolation in case if your only goal to eliminate ugly string concatenations and boring string conversions:

var yourMessage = `Your text ${yourVariable} your text continued ${yourExpression} and so on.`


At the right side of the assignment statement the delimiters are neither single or double quotes, instead a special char called backtick or grave accent.

The TypeScript compiler will translate your right side special literal to a string concatenation expression. With other words this syntax is not relies the ECMAScript 6 feature instead a native TypeScript feature. Your generated javascript code remains compatible.

MySQL - Get row number on select

Take a look at this.

Change your query to:

SET @rank=0;
SELECT @rank:=@rank+1 AS rank, itemID, COUNT(*) as ordercount
  FROM orders
  ORDER BY ordercount DESC;
SELECT @rank;

The last select is your count.

How do you check in python whether a string contains only numbers?

You'll want to use the isdigit method on your str object:

if len(isbn) == 10 and isbn.isdigit():

From the isdigit documentation:


Return True if all characters in the string are digits and there is at least one character, False otherwise. Digits include decimal characters and digits that need special handling, such as the compatibility superscript digits. This covers digits which cannot be used to form numbers in base 10, like the Kharosthi numbers. Formally, a digit is a character that has the property value Numeric_Type=Digit or Numeric_Type=Decimal.

Creating a new column based on if-elif-else condition

df.loc[df['A'] == df['B'], 'C'] = 0
df.loc[df['A'] > df['B'], 'C'] = 1
df.loc[df['A'] < df['B'], 'C'] = -1

Easy to solve using indexing. The first line of code reads like so, if column A is equal to column B then create and set column C equal to 0.

Where can I find "make" program for Mac OS X Lion?

Have you installed Xcode and the developer tools? I think make, along with gcc and friends, is installed with that and not before. Xcode 4.1 for Lion is free.

Adding Buttons To Google Sheets and Set value to Cells on clicking

You can insert an image that looks like a button. Then attach a script to the image.

  • INSERT menu
  • Image

Insert Image

You can insert any image. The image can be edited in the spreadsheet

Edit Image

Image of a Button

Image of Button

Assign a function name to an image:

Assign Function

Setting the value of checkbox to true or false with jQuery

Try this:


<input type="checkbox" value="FALSE" />


$("input[type='checkbox']").on('change', function(){
  $(this).val(this.checked ? "TRUE" : "FALSE");


Please bear in mind that unchecked checkbox will not be submitted in regular form, and you should use hidden filed in order to do it.

Are email addresses case sensitive?

Way late to this post, but I've got something slightly different to say...

>> "Are email addresses case sensitive?"

Well, "It Depends..." (TM)

Some organizations actually think that's a good idea and their email servers enforce case sensitivity.

So, for those crazy places, "Yes, Emails are case sensitive."

Note: Just because a specification says you can do something does not mean it is a good idea to do so.

The principle of KISS suggests that our systems use case insensitive emails.

Whereas the Robustness principle suggests that we accept case sensitive emails.


  • Store emails with case sensitivity
  • Send emails with case sensitivity
  • Perform internal searches with case insensitivity

This would mean that if this email already exists: [email protected]

... and another user comes along and wants to use this email: [email protected]

... that our case insensitive searching logic would return a "That email already exists" error message.

Now, you have a decision to make: Is that solution adequate in your case?

If not, you could charge a convenience fee to those clients that demand support for their case sensitive emails and implement custom logic that allows the [email protected] into your system, even if [email protected] already exists.

In which case your email search/validation logic might look like something this pseudocode:

if (user.paidEmailFee) {
   // case sensitive email
   query = "select * from users where email LIKE ' + + '"
} else {
   // case insensitive email
   query = "select * from users where email ILIKE ' + + '"

This way, you are mostly enforcing case insensitivity but allowing customers to pay for this support if they are using email systems that support such nonsense.

p.s. ILIKE is a PostgreSQL keyword:

Floating point comparison functions for C#

From Bruce Dawson's paper on comparing floats, you can also compare floats as integers. Closeness is determined by least significant bits.

public static bool AlmostEqual2sComplement( float a, float b, int maxDeltaBits ) 
    int aInt = BitConverter.ToInt32( BitConverter.GetBytes( a ), 0 );
    if ( aInt <  0 )
        aInt = Int32.MinValue - aInt;  // Int32.MinValue = 0x80000000

    int bInt = BitConverter.ToInt32( BitConverter.GetBytes( b ), 0 );
    if ( bInt < 0 )
        bInt = Int32.MinValue - bInt;

    int intDiff = Math.Abs( aInt - bInt );
    return intDiff <= ( 1 << maxDeltaBits );

EDIT: BitConverter is relatively slow. If you're willing to use unsafe code, then here is a very fast version:

    public static unsafe int FloatToInt32Bits( float f )
        return *( (int*)&f );

    public static bool AlmostEqual2sComplement( float a, float b, int maxDeltaBits )
        int aInt = FloatToInt32Bits( a );
        if ( aInt < 0 )
            aInt = Int32.MinValue - aInt;

        int bInt = FloatToInt32Bits( b );
        if ( bInt < 0 )
            bInt = Int32.MinValue - bInt;

        int intDiff = Math.Abs( aInt - bInt );
        return intDiff <= ( 1 << maxDeltaBits );

What does this thread join code mean?

Simply put:
t1.join() returns after t1 is completed.
It doesn't do anything to thread t1, except wait for it to finish.
Naturally, code following t1.join() will be executed only after t1.join() returns.

ASP.NET Identity DbContext confusion

If you drill down through the abstractions of the IdentityDbContext you'll find that it looks just like your derived DbContext. The easiest route is Olav's answer, but if you want more control over what's getting created and a little less dependency on the Identity packages have a look at my question and answer here. There's a code example if you follow the link, but in summary you just add the required DbSets to your own DbContext subclass.

How do I remove a MySQL database?

If you are using an SQL script when you are creating your database and have any users created by your script, you need to drop them too. Lastly you need to flush the users; i.e., force MySQL to read the user's privileges again.


drop schema <database_name>;
-- Same as `drop database <database_name>`

drop user <a_user_name>;
-- You may need to add a hostname e.g `drop user bob@localhost`


Good luck!

converting json to string in python

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

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

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

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

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

iPad browser WIDTH & HEIGHT standard

There's no simple answer to this question. Apple's mobile version of WebKit, used in iPhones, iPod Touches, and iPads, will scale the page to fit the screen, at which point the user can zoom in and out freely.

That said, you can design your page to minimize the amount of zooming necessary. Your best bet is to make the width and height the same as the lower resolution of the iPad, since you don't know which way it's oriented; in other words, you would make your page 768x768, so that it will fit well on the iPad's screen whether it's oriented to be 1024x768 or 768x1024.

More importantly, you'd want to design your page with big controls with lots of space that are easy to hit with your thumbs - you could easily design a 768x768 page that was very cluttered and therefore required lots of zooming. To accomplish this, you'll likely want to divide your controls among a number of web pages.

On the other hand, it's not the most worthwhile pursuit. If while designing you find opportunities to make your page more "finger-friendly", then go for it...but the reality is that iPad users are very comfortable with moving around and zooming in and out of the page to get to things because it's necessary on most web sites. If anything, you probably want to design it so that it's conducive to this type of navigation.

Make boxes with relevant grouped data that can be easily double-tapped to focus on, and keep related controls close to each other. iPad users will most likely appreciate a page that facilitates the familiar zoom-and-pan navigation they're accustomed to more than they will a page that has fewer controls so that they don't have to.

How to return a specific element of an array?

I want to return odd numbers of an array

If i read that correctly, you want something like this?

List<Integer> getOddNumbers(int[] integers) {
  List<Integer> oddNumbers = new ArrayList<Integer>();
  for (int i : integers)
    if (i % 2 != 0)
  return oddNumbers;

How do I remove javascript validation from my eclipse project?

I was able to exclude the 1.1.1 in Juno by selecting Add Multiple next to the Exlusion Patterns, which brings up the tree, then drilling down to the jquery-mobile folder and selecting that.

This corrected all the warnings for the library!

delete all record from table in mysql

It’s because you tried to update a table without a WHERE that uses a KEY column.

The quick fix is to add SET SQL_SAFE_UPDATES=0; before your query :



close the safe update mode. Edit -> Preferences -> SQL Editor -> SQL Editor remove Forbid UPDATE and DELETE statements without a WHERE clause (safe updates) .

BTW you can use TRUNCATE TABLE tablename; to delete all the records .

How to get all privileges back to the root user in MySQL?

If you facing grant permission access denied problem, you can try mysql to fix the problem:

grant all privileges on . to root@'localhost' identified by 'Your password';

grant all privileges on . to root@'IP ADDRESS' identified by 'Your password?';

your can try this on any mysql user, its working.

Use below command to login mysql with iP address.

mysql -h -u root -p

Cannot add a project to a Tomcat server in Eclipse

In my case, the .project file was read-only (it was pulled from the source code control system that way). Making it writable resolved the issue.

Eclipse v4.7 (Oxygen).

qmake: could not find a Qt installation of ''

sudo apt-get install qt5-default works for me.

$ aptitude show qt5-default
tells that

This package sets Qt 5 to be the default Qt version to be used when using development binaries like qmake. It provides a default configuration for qtchooser, but does not prevent alternative Qt installations from being used.

Replace and overwrite instead of appending

Using truncate(), the solution could be

import re
#open the xml file for reading:
with open('path/test.xml','r+') as f:
    #convert to string:
    data =

What datatype to use when storing latitude and longitude data in SQL databases?

For longitudes use: Decimal(9,6), and latitudes use: Decimal(8,6)

If you're not used to precision and scale parameters, here's a format string visual:

###.###### and ##.######

Terminating a script in PowerShell

Terminates this process and gives the underlying operating system the specified exit code.


This will allow you to exit with a specific exit code, that can be picked up from the caller.

ascending/descending in LINQ - can one change the order via parameter?

In terms of how this is implemented, this changes the method - from OrderBy/ThenBy to OrderByDescending/ThenByDescending. However, you can apply the sort separately to the main query...

var qry = from .... // or just dataList.AsEnumerable()/AsQueryable()

if(sortAscending) {
    qry = qry.OrderBy(x=>x.Property);
} else {
    qry = qry.OrderByDescending(x=>x.Property);

Any use? You can create the entire "order" dynamically, but it is more involved...

Another trick (mainly appropriate to LINQ-to-Objects) is to use a multiplier, of -1/1. This is only really useful for numeric data, but is a cheeky way of achieving the same outcome.

Is this the proper way to do boolean test in SQL?

If u r using SQLite3 beware:

It takes only 't' or 'f'. Not 1 or 0. Not TRUE OR FALSE.

Just learned the hard way.

Getting current date and time in JavaScript

.getDay returns day of week. You need .getDate instead. .getMonth returns values from 0 to 11. You'll need to add 1 to the result to get "human" month number.

How do I POST form data with UTF-8 encoding by using curl?

You CAN use UTF-8 in the POST request, all you need is to specify the charset in your request.

You should use this request:

curl -X POST -H "Content-Type: application/x-www-form-urlencoded; charset=utf-8" --data-ascii "content=derinhält&date=asdf"

Switch in Laravel 5 - Blade

Updated 2020 Answer

Since Laravel 5.5 the @switch is built into the Blade. Use it as shown below.

        <span> `E-mail` input is empty!</span>

        <span>`Password` input is empty!</span>

        <span>Something went wrong, please try again</span>

Older Answer

Unfortunately Laravel Blade does not have switch statement. You can use Laravel if else approach or use use plain PHP switch. You can use plain PHP in blade templates like in any other PHP application. Starting from Laravel 5.2 and up use @php statement.

Option 1:

@if ($login_error == 1)
    `E-mail` input is empty!
@elseif ($login_error == 2)
    `Password` input is empty!

How to install OpenSSL in windows 10?

In case you have Git installed,

you can open the Git Bash (shift pressed + right click in the folder -> Git Bash Here) and use openssl command right in the Bash

Override and reset CSS style: auto or none don't work

The best way that I've found to revert a min-width setting is:

min-width: 0;
min-width: unset;

unset is in the spec, but some browsers (IE 10) do not respect it, so 0 is a good fallback in most cases. min-width: 0;

Is it acceptable and safe to run pip install under sudo?

Use a virtual environment:

$ virtualenv myenv
.. some output ..
$ source myenv/bin/activate
(myenv) $ pip install what-i-want

You only use sudo or elevated permissions when you want to install stuff for the global, system-wide Python installation.

It is best to use a virtual environment which isolates packages for you. That way you can play around without polluting the global python install.

As a bonus, virtualenv does not need elevated permissions.

How can I set focus on an element in an HTML form using JavaScript?

For what it's worth, you can use the autofocus attribute on HTML5 compatible browsers. Works even on IE as of version 10.

<input name="myinput" value="whatever" autofocus />

How to set array length in c# dynamically

Typically, arrays require constants to initialize their size. You could sweep over nvPairs once to get the length, then "dynamically" create an array using a variable for length like this.

InputProperty[] ip = (InputProperty[])Array.CreateInstance(typeof(InputProperty), length);

I wouldn't recommend it, though. Just stick with the

List<InputProperty> ip = ...
update.Items = ip.ToArray();

solution. It's not that much less performant, and way better looking.

Calling Javascript from a html form

Remove javascript: from onclick=".., onsubmit=".. declarations

javascript: prefix is used only in href="" or similar attributes (not events related)

how to create insert new nodes in JsonNode?

These methods are in ObjectNode: the division is such that most read operations are included in JsonNode, but mutations in ObjectNode and ArrayNode.

Note that you can just change first line to be:

ObjectNode jNode = mapper.createObjectNode();
// version ObjectMapper has should return ObjectNode type


ObjectNode jNode = (ObjectNode) objectCodec.createObjectNode();
// ObjectCodec is in core part, must be of type JsonNode so need cast

How do I (or can I) SELECT DISTINCT on multiple columns?

If your DBMS doesn't support distinct with multiple columns like this:

select distinct(col1, col2) from table

Multi select in general can be executed safely as follows:

select distinct * from (select col1, col2 from table ) as x

As this can work on most of the DBMS and this is expected to be faster than group by solution as you are avoiding the grouping functionality.

Optimal way to Read an Excel file (.xls/.xlsx)

Using OLE Query, it's quite simple (e.g. sheetName is Sheet1):

DataTable LoadWorksheetInDataTable(string fileName, string sheetName)
    DataTable sheetData = new DataTable();
    using (OleDbConnection conn = this.returnConnection(fileName))
       // retrieve the data using data adapter
       OleDbDataAdapter sheetAdapter = new OleDbDataAdapter("select * from [" + sheetName + "$]", conn);
    return sheetData;

private OleDbConnection returnConnection(string fileName)
    return new OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + fileName + "; Jet OLEDB:Engine Type=5;Extended Properties=\"Excel 8.0;\"");

For newer Excel versions:

return new OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + fileName + ";Extended Properties=Excel 12.0;");

You can also use Excel Data Reader an open source project on CodePlex. Its works really well to export data from Excel sheets.

The sample code given on the link specified:

FileStream stream = File.Open(filePath, FileMode.Open, FileAccess.Read);

//1. Reading from a binary Excel file ('97-2003 format; *.xls)
IExcelDataReader excelReader = ExcelReaderFactory.CreateBinaryReader(stream);
//2. Reading from a OpenXml Excel file (2007 format; *.xlsx)
IExcelDataReader excelReader = ExcelReaderFactory.CreateOpenXmlReader(stream);
//3. DataSet - The result of each spreadsheet will be created in the result.Tables
DataSet result = excelReader.AsDataSet();
//4. DataSet - Create column names from first row
excelReader.IsFirstRowAsColumnNames = true;
DataSet result = excelReader.AsDataSet();

//5. Data Reader methods
while (excelReader.Read())

//6. Free resources (IExcelDataReader is IDisposable)

Reference: How do I import from Excel to a DataSet using Microsoft.Office.Interop.Excel?

MySQL - select data from database between two dates

You need to use '2011-12-07' as the end point as a date without a time default to time 00:00:00.

So what you have actually written is interpreted as:

 SELECT users.* 
 FROM   users
 WHERE  created_at >= '2011-12-01 00:00:00' 
   AND  created_at <= '2011-12-06 00:00:00'

And your time stamp is: 2011-12-06 10:45:36 which is not between those points.
Change this too:

 SELECT users.* 
 FROM   users
 WHERE  created_at >= '2011-12-01'  -- Implied 00:00:00
   AND  created_at <  '2011-12-07'  -- Implied 00:00:00 and smaller than 
                                   --                  thus any time on 06

How do I git rm a file without deleting it from disk?

git rm --cached file

should do what you want.

You can read more details at git help rm

javascript regex - look behind alternative?

If you can look ahead but back, you could reverse the string first and then do a lookahead. Some more work will need to be done, of course.

Prepend text to beginning of string

you could also do it this way


Using Python's list index() method on a list of tuples or objects?

tuple_list = [("pineapple", 5), ("cherry", 7), ("kumquat", 3), ("plum", 11)]

def eachtuple(tupple, pos1, val):
    for e in tupple:
        if e == val:
            return True

for e in tuple_list:
    if eachtuple(e, 1, 7) is True:
        print tuple_list.index(e)

for e in tuple_list:
    if eachtuple(e, 0, "kumquat") is True:
        print tuple_list.index(e)

How to create timer in angular2

With rxjs 6.2.2 and Angular 6.1.7, I was getting an:

Observable.timer is not a function

error. This was resolved by replacing Observable.timer with timer:

import { timer, Subscription } from 'rxjs';

private myTimerSub: Subscription;    

    const ti = timer(2000,1000);    
    this.myTimerSub = ti.subscribe(t => {    

ngOnDestroy() {    

How to use *ngIf else?

In Angular 4.x.x You can use ngIf in four way to achieve simple if else procedure:

  1. Just Use If

    <div *ngIf="isValid">
        If isValid is true
  2. Using If with Else (Please notice to templateName)

    <div *ngIf="isValid; else templateName">
        If isValid is true
    <ng-template #templateName>
        If isValid is false
  3. Using If with Then (Please notice to templateName)

    <div *ngIf="isValid; then templateName">
        Here is never showing
    <ng-template #templateName>
        If isValid is true
  4. Using If with Then and Else

    <div *ngIf="isValid; then thenTemplateName else elseTemplateName">
        Here is never showing
    <ng-template #thenTemplateName>
        If isValid is true
    <ng-template #elseTemplateName>
        If isValid is false

Tip: ngIf evaluates the expression and then renders the then or else template in its place when expression is truthy or falsy respectively. Typically the:

  • then template is the inline template of ngIf unless bound to a different value.
  • else template is blank unless it is bound.

null check in jsf expression language

Use empty (it checks both nullness and emptiness) and group the nested ternary expression by parentheses (EL is in certain implementations/versions namely somewhat problematic with nested ternary expressions). Thus, so:

styleClass="#{empty obj.validationErrorMap ? ' ' :  
 (obj.validationErrorMap.contains('key') ? 'highlight_field' : 'highlight_row')}"

If still in vain (I would then check JBoss EL configs), use the "normal" EL approach:

styleClass="#{empty obj.validationErrorMap ? ' ' :  
 (obj.validationErrorMap['key'] ne null ? 'highlight_field' : 'highlight_row')}"

Update: as per the comments, the Map turns out to actually be a List (please work on your naming conventions). To check if a List contains an item the "normal" EL way, use JSTL fn:contains (although not explicitly documented, it works for List as well).

styleClass="#{empty obj.validationErrorMap ? ' ' :  
 (fn:contains(obj.validationErrorMap, 'key') ? 'highlight_field' : 'highlight_row')}"

Pad left or right with string.format (not padleft or padright) with arbitrary string


    dim input as string = "SPQR"
    dim format as string =""
    dim result as string = ""

    'pad left:
    format = "{0,-8}"
    result = String.Format(format,input)
    'result = "SPQR    "

    'pad right
    format = "{0,8}"
    result = String.Format(format,input)
    'result = "    SPQR"

In Windows cmd, how do I prompt for user input and use the result in another command?

set /p choice= "Please Select one of the above options :" 
echo '%choice%'

The space after = is very important.

How to fix Error: "Could not find schema information for the attribute/element" by creating schema

Most of what I write has already been covered by Pressacco, but this is specific to SpecFlow.

I was getting this message for the <specFlow> element and therefore I added a specflow.xsd file to the solution this answer (with some modifications to allow for the <plugins> element).

Thereafter I (like Pressacco), right clicked within the file buffer of app.config and selected properties, and within Schemas, I added "specflow.xsd" to the end. The entirety of Schemas now reads:

"C:\Program Files (x86)\Microsoft Visual Studio 12.0\xml\Schemas\1033\DotNetConfig.xsd" "C:\Program Files (x86)\Microsoft Visual Studio 12.0\xml\Schemas\EntityFrameworkConfig_6_1_0.xsd" "C:\Program Files (x86)\Microsoft Visual Studio 12.0\xml\Schemas\RazorCustomSchema.xsd" "specflow.xsd"

How to make background of table cell transparent

You can do it setting the transparency via style right within the table tag:

<table id="Main table" style="background-color:rgba(0, 0, 0, 0);">

The last digit in the rgba function is for transparency. 1 means 100% opaque, while 0 stands for 100% transparent.

SQL Server Subquery returned more than 1 value. This is not permitted when the subquery follows =, !=, <, <= , >, >=

The select statement in the cost part of your select is returning more than one value. You need to add more where clauses, or use an aggregation.

How do I do multiple CASE WHEN conditions using SQL Server 2008?

    when a.REASONID in ('02','03','04','05','06') then
        case b.CALSOC 
            when '1' then 'yes' 
            when '2' then 'no' 
            else 'no' 
    else 'no' 

How to completely DISABLE any MOUSE CLICK

You can add a simple css3 rule in the body or in specific div, use pointer-events: none; property.

Create a circular button in BS3

you can do something like adding a class to add border radius


<a href="#" class="btn btn-default btn-circle"><i class="fa fa-user"></i></a>


.btn-circle {
  width: 30px;
  height: 30px;
  text-align: center;
  padding: 6px 0;
  font-size: 12px;
  line-height: 1.42;
  border-radius: 15px;

in case you wanted to change dimension you need to change the font size or padding accordingly

Read .csv file in C

The following code is in plain c language and handles blank spaces. It only allocates memory once, so one free() is needed, for each processed line.

/* Tiny CSV Reader */
/* Copyright (C) 2015, Deligiannidis Konstantinos

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program.  If not, see <>.  */

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

/* For more that 100 columns or lines (when delimiter = \n), minor modifications are needed. */
int getcols( const char * const line, const char * const delim, char ***out_storage )

const char *start_ptr, *end_ptr, *iter;
char **out;
int i;                                          //For "for" loops in the old c style.
int tokens_found = 1, delim_size, line_size;    //Calculate "line_size" indirectly, without strlen() call.
int start_idx[100], end_idx[100];   //Store the indexes of tokens. Example "Power;": loc('P')=1, loc(';')=6
//Change 100 with MAX_TOKENS or use malloc() for more than 100 tokens. Example: "b1;b2;b3;...;b200"

if ( *out_storage != NULL )                 return -4;  //This SHOULD be NULL: Not Already Allocated
if ( !line || !delim )                      return -1;  //NULL pointers Rejected Here
if ( (delim_size = strlen( delim )) == 0 )  return -2;  //Delimiter not provided

start_ptr = line;   //Start visiting input. We will distinguish tokens in a single pass, for good performance.
                    //Then we are allocating one unified memory region & doing one memory copy.
while ( ( end_ptr = strstr( start_ptr, delim ) ) ) {

    start_idx[ tokens_found -1 ] = start_ptr - line;    //Store the Index of current token
    end_idx[ tokens_found - 1 ] = end_ptr - line;       //Store Index of first character that will be replaced with
                                                        //'\0'. Example: "arg1||arg2||end" -> "arg1\0|arg2\0|end"
    tokens_found++;                                     //Accumulate the count of tokens.
    start_ptr = end_ptr + delim_size;                   //Set pointer to the next c-string within the line

for ( iter = start_ptr; (*iter!='\0') ; iter++ );

start_idx[ tokens_found -1 ] = start_ptr - line;    //Store the Index of current token: of last token here.
end_idx[ tokens_found -1 ] = iter - line;           //and the last element that will be replaced with \0

line_size = iter - line;    //Saving CPU cycles: Indirectly Count the size of *line without using strlen();

int size_ptr_region = (1 + tokens_found)*sizeof( char* );   //The size to store pointers to c-strings + 1 (*NULL).
out = (char**) malloc( size_ptr_region + ( line_size + 1 ) + 5 );   //Fit everything is all memory.
//It reserves a contiguous space for both (char**) pointers AND string region. 5 Bytes for "Out of Range" tests.
*out_storage = out;     //Update the char** pointer of the caller function.

//"Out of Range" TEST. Verify that the extra reserved characters will not be changed. Assign Some Values.
//char *extra_chars = (char*) out + size_ptr_region + ( line_size + 1 );
//extra_chars[0] = 1; extra_chars[1] = 2; extra_chars[2] = 3; extra_chars[3] = 4; extra_chars[4] = 5;

for ( i = 0; i < tokens_found; i++ )    //Assign adresses first part of the allocated memory pointers that point to
    out[ i ] = (char*) out + size_ptr_region + start_idx[ i ];  //the second part of the memory, reserved for Data.
out[ tokens_found ] = (char*) NULL; //[ ptr1, ptr2, ... , ptrN, (char*) NULL, ... ]: We just added the (char*) NULL.
                                                    //Now assign the Data: c-strings. (\0 terminated strings):
char *str_region = (char*) out + size_ptr_region;   //Region inside allocated memory which contains the String Data.
memcpy( str_region, line, line_size );   //Copy input with delimiter characters: They will be replaced with \0.

//Now we should replace: "arg1||arg2||arg3" with "arg1\0|arg2\0|arg3". Don't worry for characters after '\0'
//They are not used in standard c lbraries.
for( i = 0; i < tokens_found; i++) str_region[ end_idx[ i ] ] = '\0';

//"Out of Range" TEST. Wait until Assigned Values are Printed back.
//for ( int i=0; i < 5; i++ ) printf("c=%x ", extra_chars[i] ); printf("\n");

// *out memory should now contain (example data):
//[ ptr1, ptr2,...,ptrN, (char*) NULL, "token1\0", "token2\0",...,"tokenN\0", 5 bytes for tests ]
//   |__________________________________^           ^              ^             ^
//          |_______________________________________|              |             |
//                   |_____________________________________________|      These 5 Bytes should be intact.

return tokens_found;

int main()


char in_line[] = "Arg1;;Th;s is not Del;m;ter;;Arg3;;;;Final";
char delim[] = ";;";
char **columns;
int i;

columns = NULL; //Should be NULL to indicate that it is not assigned to allocated memory. Otherwise return -4;

int cols_found = getcols( in_line, delim, &columns);
for ( i = 0; i < cols_found; i++ ) printf("Column[ %d ] = %s\n", i, columns[ i ] );  //<- (1st way).
// (2nd way) // for ( i = 0; columns[ i ]; i++) printf("start_idx[ %d ] = %s\n", i, columns[ i ] );

free( columns );    //Release the Single Contiguous Memory Space.
columns = NULL;     //Pointer = NULL to indicate it does not reserve space and that is ready for the next malloc().

printf("\n\nExample2, Nested:\n\n");

char example_file[] = "ID;Day;Month;Year;Telephone;email;Date of registration\n"
        "1;Sunday;january;2009;123-124-456;[email protected];2015-05-13\n"
        "2;Monday;March;2011;(+30)333-22-55;[email protected];2009-05-23";

char **rows;
int j;

rows = NULL; //getcols() requires it to be NULL. (Avoid dangling pointers, leaks e.t.c).

getcols( example_file, "\n", &rows);
for ( i = 0; rows[ i ]; i++) {
        printf("Line[ %d ] = %s\n", i, rows[ i ] );
        char **columnX = NULL;
        getcols( rows[ i ], ";", &columnX);
        for ( j = 0; columnX[ j ]; j++) printf("  Col[ %d ] = %s\n", j, columnX[ j ] );
        free( columnX );

free( rows );
rows = NULL;

return 0;

Why doesn't GCC optimize a*a*a*a*a*a to (a*a*a)*(a*a*a)?

As Lambdageek pointed out float multiplication is not associative and you can get less accuracy, but also when get better accuracy you can argue against optimisation, because you want a deterministic application. For example in game simulation client/server, where every client has to simulate the same world you want floating point calculations to be deterministic.

javascript node.js next()

This appears to be a variable naming convention in Node.js control-flow code, where a reference to the next function to execute is given to a callback for it to kick-off when it's done.

See, for example, the code samples here:

Let's look at the example you posted:

function loadUser(req, res, next) {
  if (req.session.user_id) {
    User.findById(req.session.user_id, function(user) {
      if (user) {
        req.currentUser = user;
        return next();
      } else {
  } else {

app.get('/documents.:format?', loadUser, function(req, res) {
  // ...

The loadUser function expects a function in its third argument, which is bound to the name next. This is a normal function parameter. It holds a reference to the next action to perform and is called once loadUser is done (unless a user could not be found).

There's nothing special about the name next in this example; we could have named it anything.

Set custom attribute using JavaScript

Please use dataset

var article = document.querySelector('#electriccars'),
    data = article.dataset;

// data.columns -> "3"
// data.indexnumber -> "12314"
// data.parent -> "cars"

so in your case for setting data:

getElementById('item1').dataset.icon = "base2.gif";

Can I add jars to maven 2 build classpath without installing them?

Maven install plugin has command line usage to install a jar into the local repository, POM is optional but you will have to specify the GroupId, ArtifactId, Version and Packaging (all the POM stuff).

Regular cast vs. static_cast vs. dynamic_cast

You should look at the article C++ Programming/Type Casting.

It contains a good description of all of the different cast types. The following taken from the above link:


const_cast(expression) The const_cast<>() is used to add/remove const(ness) (or volatile-ness) of a variable.


static_cast(expression) The static_cast<>() is used to cast between the integer types. 'e.g.' char->long, int->short etc.

Static cast is also used to cast pointers to related types, for example casting void* to the appropriate type.


Dynamic cast is used to convert pointers and references at run-time, generally for the purpose of casting a pointer or reference up or down an inheritance chain (inheritance hierarchy).


The target type must be a pointer or reference type, and the expression must evaluate to a pointer or reference. Dynamic cast works only when the type of object to which the expression refers is compatible with the target type and the base class has at least one virtual member function. If not, and the type of expression being cast is a pointer, NULL is returned, if a dynamic cast on a reference fails, a bad_cast exception is thrown. When it doesn't fail, dynamic cast returns a pointer or reference of the target type to the object to which expression referred.


Reinterpret cast simply casts one type bitwise to another. Any pointer or integral type can be casted to any other with reinterpret cast, easily allowing for misuse. For instance, with reinterpret cast one might, unsafely, cast an integer pointer to a string pointer.

Conversion failed when converting date and/or time from character string in SQL SERVER 2008

If you're trying to insert in to last_accessed_on, which is a DateTime2, then your issue is with the fact that you are converting it to a varchar in a format that SQL doesn't understand.

If you modify your code to this, it should work, note the format of your date has been changed to: YYYY-MM-DD hh:mm:ss:

UPDATE  student_queues 
SET  Deleted=0, 
     last_accessed_on=CONVERT(datetime2,'2014-07-23 09:37:00')
WHERE std_id IN ('2144-384-11564') AND reject_details='REJECT'

Or if you want to use CAST, replace with:

CAST('2014-07-23 09:37:00.000' AS datetime2)

This is using the SQL ISO Date Format.

How to make sure that string is valid JSON using JSON.NET

Here is a TryParse extension method based on Habib's answer:

public static bool TryParse(this string strInput, out JToken output)
    if (String.IsNullOrWhiteSpace(strInput))
        output = null;
        return false;
    strInput = strInput.Trim();
    if ((strInput.StartsWith("{") && strInput.EndsWith("}")) || //For object
        (strInput.StartsWith("[") && strInput.EndsWith("]"))) //For array
            output = JToken.Parse(strInput);
            return true;
        catch (JsonReaderException jex)
            //Exception in parsing json
            //optional: LogError(jex);
            output = null;
            return false;
        catch (Exception ex) //some other exception
            //optional: LogError(ex);
            output = null;
            return false;
        output = null;
        return false;


JToken jToken;
if (strJson.TryParse(out jToken))
    // work with jToken
    // not valid json

Custom Listview Adapter with filter Android

In your CustomAdapter class implement filterable.

listview with search search listview

 public class CustomAdapter extends BaseAdapter implements Filterable {

    private List<ItemsModel> itemsModelsl;
    private List<ItemsModel> itemsModelListFiltered;
    private Context context;

    public CustomAdapter(List<ItemsModel> itemsModelsl, Context context) {
        this.itemsModelsl = itemsModelsl;
        this.itemsModelListFiltered = itemsModelsl;
        this.context = context;

    public int getCount() {
        return itemsModelListFiltered.size();

    public Object getItem(int position) {
        return itemsModelListFiltered.get(position);

    public long getItemId(int position) {
        return position;

    public View getView(final int position, View convertView, ViewGroup parent) {
        View view = getLayoutInflater().inflate(R.layout.row_items,null);

        TextView names = view.findViewById(;
        TextView emails = view.findViewById(;
        ImageView imageView = view.findViewById(;


        view.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                Log.e("main activity","item clicked");
                startActivity(new Intent(MainActivity.this,ItemsPreviewActivity.class).putExtra("items",itemsModelListFiltered.get(position)));


        return view;

    public Filter getFilter() {
        Filter filter = new Filter() {
            protected FilterResults performFiltering(CharSequence constraint) {

                FilterResults filterResults = new FilterResults();
                if(constraint == null || constraint.length() == 0){
                    filterResults.count = itemsModelsl.size();
                    filterResults.values = itemsModelsl;

                    List<ItemsModel> resultsModel = new ArrayList<>();
                    String searchStr = constraint.toString().toLowerCase();

                    for(ItemsModel itemsModel:itemsModelsl){
                        if(itemsModel.getName().contains(searchStr) || itemsModel.getEmail().contains(searchStr)){

                         filterResults.count = resultsModel.size();
                            filterResults.values = resultsModel;


                return filterResults;

            protected void publishResults(CharSequence constraint, FilterResults results) {

                itemsModelListFiltered = (List<ItemsModel>) results.values;

        return filter;


You can get the whole tutorial here: ListView With Search/Filter and OnItemClickListener

Github Source Code

HttpClient does not exist in .net 4.0: what can I do?

Referring to the answers above, I am only adding this to help clarify things. It is possible to use HttpClient from .Net 4.0, and you have to install the package from here

However, the text is very confusion and contradicts itself.

This package is not supported in Visual Studio 2010, and is only required for projects targeting .NET Framework 4.5, Windows 8, or Windows Phone 8.1 when consuming a library that uses this package.

But underneath it states that these are the supported platforms.

Supported Platforms:

  • .NET Framework 4

  • Windows 8

  • Windows Phone 8.1

  • Windows Phone Silverlight 7.5

  • Silverlight 4

  • Portable Class Libraries

Ignore what it ways about targeting .Net 4.5. This is wrong. The package is all about using HttpClient in .Net 4.0. However, you may need to use VS2012 or higher. Not sure if it works in VS2010, but that may be worth testing.

How to wait in bash for several subprocesses to finish and return exit code !=0 when any subprocess ends with code !=0?

Trapping CHLD signal may not work because you can lose some signals if they arrived simultaneously.


trap 'rm -f $tmpfile' EXIT


doCalculations() {
    echo start job $i...
    sleep $((RANDOM % 5)) 
    echo ...end job $i
    exit $((RANDOM % 10))


for i in $( seq 1 $number_of_jobs )
    ( trap "echo job$i : exit value : \$? >> $tmpfile" EXIT; doCalculations ) &


while read res; do
    echo "$res"
    let i++
done < "$tmpfile"

echo $i jobs done !!!

console.log timestamps in Chrome?

This adds a "log" function to the local scope (using this) using as many arguments as you want:

this.log = function() {
    var args = [];
    args.push('[' + new Date().toUTCString() + '] ');
    //now add all the other arguments that were passed in:
    for (var _i = 0, _len = arguments.length; _i < _len; _i++) {
      arg = arguments[_i];

    //pass it all into the "real" log function
    window.console.log.apply(window.console, args); 

So you can use it:

this.log({test: 'log'}, 'monkey', 42);

Outputs something like this:

[Mon, 11 Mar 2013 16:47:49 GMT] Object {test: "log"} monkey 42

Android: Storing username and password?

You can also look at the SampleSyncAdapter sample from the SDK. It may help you.

How do I use Spring Boot to serve static content located in Dropbox folder?

Based on @Dave Syers answer I add the following class to my Spring Boot project:

public class StaticResourceConfiguration extends WebMvcConfigurerAdapter {

 private static final Logger LOG = LoggerFactory.getLogger(StaticResourceConfiguration.class);

 private String staticPath;

 public void addResourceHandlers(ResourceHandlerRegistry registry) {

    if(staticPath != null) {"Serving static content from " + staticPath);
        registry.addResourceHandler("/**").addResourceLocations("file:" + staticPath);

 // see
 public void addViewControllers(ViewControllerRegistry registry) {

This allows me to start my spring boot app with the parameter --static.path like

java -jar spring-app-1.0-SNAPSHOT.jar --static.path=/path/to/my/static-files/

This can be very handy for development and testing.

Git pull till a particular commit

If you merge a commit into your branch, you should get all the history between.


$ git init ./
Initialized empty Git repository in /Users/dfarrell/git/demo/.git/
$ echo 'a' > letter
$ git add letter
$ git commit -m 'Initial Letter'
[master (root-commit) 6e59e76] Initial Letter
 1 file changed, 1 insertion(+)
 create mode 100644 letter
$ echo 'b' >> letter
$ git add letter && git commit -m 'Adding letter'
[master 7126e6d] Adding letter
 1 file changed, 1 insertion(+)
$ echo 'c' >> letter; git add letter && git commit -m 'Adding letter'
[master f2458be] Adding letter
 1 file changed, 1 insertion(+)
$ echo 'd' >> letter; git add letter && git commit -m 'Adding letter'
[master 7f77979] Adding letter
 1 file changed, 1 insertion(+)
$ echo 'e' >> letter; git add letter && git commit -m 'Adding letter'
[master 790eade] Adding letter
 1 file changed, 1 insertion(+)
$ git log
commit 790eade367b0d8ab8146596cd717c25fd895302a
Author: Dan Farrell 
Date:   Thu Jul 16 14:21:26 2015 -0500

    Adding letter

commit 7f77979efd17f277b4be695c559c1383d2fc2f27
Author: Dan Farrell 
Date:   Thu Jul 16 14:21:24 2015 -0500

    Adding letter

commit f2458bea7780bf09fe643095dbae95cf97357ccc
Author: Dan Farrell 
Date:   Thu Jul 16 14:21:19 2015 -0500

    Adding letter

commit 7126e6dcb9c28ac60cb86ae40fb358350d0c5fad
Author: Dan Farrell 
Date:   Thu Jul 16 14:20:52 2015 -0500

    Adding letter

commit 6e59e7650314112fb80097d7d3803c964b3656f0
Author: Dan Farrell 
Date:   Thu Jul 16 14:20:33 2015 -0500

    Initial Letter
$ git checkout 6e59e7650314112fb80097d7d3803c964b3656f
$ git checkout 7126e6dcb9c28ac60cb86ae40fb358350d0c5fad
Note: checking out '7126e6dcb9c28ac60cb86ae40fb358350d0c5fad'.

You are in 'detached HEAD' state. You can look around, make experimental
changes and commit them, and you can discard any commits you make in this
state without impacting any branches by performing another checkout.

If you want to create a new branch to retain commits you create, you may
do so (now or later) by using -b with the checkout command again. Example:

  git checkout -b new_branch_name

HEAD is now at 7126e6d... Adding letter
$ git checkout -b B 7126e6dcb9c28ac60cb86ae40fb358350d0c5fad
Switched to a new branch 'B'
$ git pull 790eade367b0d8ab8146596cd717c25fd895302a
fatal: '790eade367b0d8ab8146596cd717c25fd895302a' does not appear to be a git repository
fatal: Could not read from remote repository.

Please make sure you have the correct access rights
and the repository exists.
$ git merge 7f77979efd17f277b4be695c559c1383d2fc2f27
Updating 7126e6d..7f77979
 letter | 2 ++
 1 file changed, 2 insertions(+)
$ cat letter

How to get everything after last slash in a URL?

First extract the path element from the URL:

from urllib.parse import urlparse
parsed= urlparse('https://www.dummy.example/this/is/PATH?q=/a/b&r=5#asx')

and then you can extract the last segment with string functions:


(example resulting to 'PATH')

Print specific part of webpage

Just use CSS to hide the content you do not want printed. When the user selects print - the page will look to the " media="print" CSS for instructions about the layout of the page.

The media="print" CSS has instructions to hide the content that we do not want printed.

<!-- CSS for the things we want to print (print view) -->
<style type="text/css" media="print">

        display: none;

<!-- CSS for the things we DO NOT want to print (web view) -->
<style type="text/css" media="screen">

      display: none;

     the stuff I DO NOT want printed is here and will be hidden - 
     and not printed when the user selects print.

<div id="PRINT_VIEW">
     the stuff I DO want printed is here.

Convert a list to a data frame

assume your list is called L,

data.frame(Reduce(rbind, L))

xampp MySQL does not start

You already have a version of mySQL installed on this machine that is using port 3306. Go into the most recent my.ini file and change the port to 3307. Restart the mySQL service and see if it comes up.

You also need to change port 3306 to 3307 in xampp\php\php.ini

PHP, Get tomorrows date from date

 $tomorrow = date("Y-m-d", strtotime('tomorrow'));


  $tomorrow = date("Y-m-d", strtotime("+1 day"));

Help Link: STRTOTIME()

Get Android .apk file VersionName or VersionCode WITHOUT installing apk

aapt dump badging test.apk | grep "VersionName" | sed -e "s/.*versionName='//" -e "s/' .*//"

This answers the question by returning only the version number as a result. However......

The goal as previously stated should be to find out if the apk on the server is newer than the one installed BEFORE attempting to download or install it. The easiest way to do this is include the version number in the filename of the apk hosted on the server eg myapp_1.01.apk

You will need to establish the name and version number of the apps already installed (if it is installed) in order to make the comparison. You will need a rooted device or a means of installing the aapt binary and busybox if they are not already included in the rom.

This script will get the list of apps from your server and compare with any installed apps. The result is a list flagged for upgrade/installation.

SERVER_LIST=$(wget -qO- "" | grep 'href' | grep '\.apk' | sed 's/.*href="//' | \
              sed 's/".*//' | grep -v '\/' | sed -E "s/%/\\\\x/g" | sed -e "s/x20/ /g" -e "s/\\\\//g")
LOCAL_LIST=$(for APP in $(pm list packages -f | sed -e 's/package://' -e 's/=.*//' | sort -u); do \
              INFO=$(echo -n $(aapt dump badging $APP | grep -e 'package: name=' -e 'application: label=')) 2>/dev/null; \
              PACKAGE=$(echo $INFO | sed "s/.*package: name='//" | sed "s/'.*$//"); \
              LABEL=$(echo $INFO | sed "s/.*application: label='//" | sed "s/'.*$//"); if [ -z "$LABEL" ]; then LABEL="$PACKAGE"; fi; \
              VERSION=$(echo $INFO | sed -e "s/.*versionName='//" -e "s/' .*//"); \
              NAME=$LABEL"_"$VERSION".apk"; echo "$NAME"; \
OFS=$IFS; IFS=$'\t\n'
    REMOTE_NAME=$(echo $REMOTE | sed 's/_.*//'); REMOTE_VER=$(echo $REMOTE | sed 's/^[^_]*_//g' | sed 's/[^0-9]*//g')
    for LOCAL in $LOCAL_LIST; do
        LOCAL_NAME=$(echo $LOCAL | sed 's/_.*//'); LOCAL_VER=$(echo $LOCAL | sed 's/^[^_]*_//g' | sed 's/[^0-9]*//g')
        if [ "$REMOTE_NAME" == "$LOCAL_NAME" ]; then INSTALLED=1; fi
        if [ "$REMOTE_NAME" == "$LOCAL_NAME" ] && [ ! "$REMOTE_VER" == "$LOCAL_VER" ]; then echo remote=$REMOTE ver=$REMOTE_VER local=$LOCAL ver=$LOCAL_VER; fi
    if [ "$INSTALLED" == "0" ]; then echo "$REMOTE"; fi

As somebody asked how to do it without using aapt. It is also possible to extract apk info with apktool and a bit of scripting. This way is slower and not simple in android but will work on windows/mac or linux as long as you have working apktool setup.

rm -f -R $TMPDIR
apktool d -q -f -s --force-manifest -o $TMPDIR $APK
APK=$(basename $APK)
VERSION=$(cat $TMPDIR/apktool.yml | grep "versionName" | sed -e "s/versionName: //")
LABEL=$(cat $TMPDIR/res/values/strings.xml | grep 'string name="title"' | sed -e 's/.*">//' -e 's/<.*//')
rm -f -R $TMPDIR
echo ${LABEL}_$(echo $V).apk

Also consider a drop folder on your server. Upload apks to it and a cron task renames and moves them to your update folder.

# Drop Folder script for renaming APKs
# Read apk file from SRC folder and move it to TGT folder while changing filename to APKLABEL_APKVERSION.apk
# If an existing version of the APK exists in the target folder then script will remove it
# Define METHOD as "aapt" or "apktool" depending upon what is available on server 

# Variables
if [ -d "$SRC" ];then mkdir -p $SRC
if [ -d "$TGT" ]then mkdir -p $TGT

# Functions
get_apk_filename () {
    if [ "$1" = "" ]; then return 1; fi
    local A="$1"
    case $METHOD in
            local D=/tmp/apktool
            rm -f -R $D
            apktool d -q -f -s --force-manifest -o $D $A
            local A=$(basename $A)
            local V=$(cat $D/apktool.yml | grep "versionName" | sed -e "s/versionName: //")
            local T=$(cat $D/res/values/strings.xml | grep 'string name="title"' | sed -e 's/.*">//' -e 's/<.*//')
            rm -f -R $D<commands>
            local A=$(aapt dump badging $A | grep -e "application-label:" -e "VersionName")
            local V=$(echo $A | sed -e "s/.*versionName='//" -e "s/' .*//")
            local T=$(echo $A | sed -e "s/.*application-label:'//" -e "s/'.*//")
    echo ${T}_$(echo $V).apk

# Begin script
for APK in $(ls "$SRC"/*.apk); do
    APKNAME=$(get_apk_filename "$APK")
    rm -f $TGT/$(echo APKNAME | sed "s/_.*//")_*.apk
    mv "$APK" "$TGT"/$APKNAME

How to find my php-fpm.sock?

I know this is old questions but since I too have the same problem just now and found out the answer, thought I might share it. The problem was due to configuration at pood.d/ directory.




listen =

change to

listen = /var/run/php5-fpm.sock

Restart both nginx and php5-fpm service afterwards and check if php5-fpm.sock already created.

How to easily initialize a list of Tuples?

Old question, but this is what I typically do to make things a bit more readable:

Func<int, string, Tuple<int, string>> tc = Tuple.Create;

var tupleList = new List<Tuple<int, string>>
    tc( 1, "cow" ),
    tc( 5, "chickens" ),
    tc( 1, "airplane" )

Horizontal swipe slider with jQuery and touch devices support?

Take a look at iScroll v4 here:

It may not be jQuery, but it works on Desktop Mobile, and iPad quite well; I've used it on many projects and combined it with jQuery.

Good Luck!

How to match all occurrences of a regex

Using scan should do the trick:


Get latest from Git branch

If you have forked a repository fro Delete your forked copy and fork it again from master.

SQLite table constraint - unique on multiple columns

If you already have a table and can't/don't want to recreate it for whatever reason, use indexes:

CREATE UNIQUE INDEX my_index ON my_table(col_1, col_2);

Using a Python subprocess call to invoke a Python script

The subprocess call is a very literal-minded system call. it can be used for any generic process...hence does not know what to do with a Python script automatically.


call ('python')

If that doesn't work, you might want to try an absolute path, and/or check permissions on your Python script...the typical fun stuff.

Remove duplicates in the list using linq

Try this extension method out. Hopefully this could help.

public static class DistinctHelper
    public static IEnumerable<TSource> DistinctBy<TSource, TKey>(this IEnumerable<TSource> source, Func<TSource, TKey> keySelector)
        var identifiedKeys = new HashSet<TKey>();
        return source.Where(element => identifiedKeys.Add(keySelector(element)));


var outputList = sourceList.DistinctBy(x => x.TargetProperty);

Git - deleted some files locally, how do I get them from a remote repository

Also, I add to do the following steps so that the git repo would be correctly linked with the IDE:

 $ git reset <commit #>

 $ git checkout <file/path>

I hope this was helpful!!

How to secure phpMyAdmin

In newer versions of phpMyAdmin access permissions for user-names + ip-addresses can be set up inside the phpMyAdmin's file. This is a much better and more robust method of restricting access (over hard-coding URLs and IP addresses into Apache's httpd.conf).

Here is a full example of how to switch to white-listing all users (no one outside this list will be allowed access), and also how to restrict user root to the local system and network only.

$cfg['Servers'][$i]['AllowDeny']['order'] = 'deny,allow';
$cfg['Servers'][$i]['AllowDeny']['rules'] = array(
    'deny % from all', // deny everyone by default, then -

    'allow % from', // allow all local users
    'allow % from ::1',

    //'allow % from SERVER_ADDRESS', // allow all from server IP

    // allow user:root access from these locations (local network)
    'allow root from localhost',
    'allow root from',
    'allow root from',
    'allow root from',
    'allow root from',

    'allow root from ::1',

    // add more usernames and their IP (or IP ranges) here -    

Source: How to Install and Secure phpMyAdmin on localhost for Windows

This gives you much more fine-grained access restrictions than Apache's URL permissions or an .htaccess file can provide, at the MySQL user name level.

Make sure that the user you are login in with, has its MySQL Host: field set to or ::1, as phpMyAdmin and MySQL are on the same system.

JSON library for C#

To give a more up to date answer to this question: yes, .Net includes JSON seriliazer/deserliazer since version 3.5 through the System.Runtime.Serialization.Json Namespace:

But according to the creator of JSON.Net, the .Net Framework compared to his open source implementation is very much slower.

How can I get city name from a latitude and longitude point?

Following Code Works Fine to Get City Name (Using Google Map Geo API) :


<p><button onclick="getLocation()">Get My Location</button></p>
<p id="demo"></p>
<script src=""></script>


var x=document.getElementById("demo");
function getLocation(){
    if (navigator.geolocation){
        x.innerHTML="Geolocation is not supported by this browser.";

function showPosition(position){

function showError(error){
        case error.PERMISSION_DENIED:
            x.innerHTML="User denied the request for Geolocation."
        case error.POSITION_UNAVAILABLE:
            x.innerHTML="Location information is unavailable."
        case error.TIMEOUT:
            x.innerHTML="The request to get user location timed out."
        case error.UNKNOWN_ERROR:
            x.innerHTML="An unknown error occurred."

function displayLocation(latitude,longitude){
    var geocoder;
    geocoder = new google.maps.Geocoder();
    var latlng = new google.maps.LatLng(latitude, longitude);

        {'latLng': latlng}, 
        function(results, status) {
            if (status == google.maps.GeocoderStatus.OK) {
                if (results[0]) {
                    var add= results[0].formatted_address ;
                    var  value=add.split(",");

                    x.innerHTML = "city name is: " + city;
                else  {
                    x.innerHTML = "address not found";
            else {
                x.innerHTML = "Geocoder failed due to: " + status;

disable horizontal scroll on mobile web

For me, the viewport meta tag actually caused a horizontal scroll issue on the Blackberry.

I removed content="initial-scale=1.0; maximum-scale=1.0; from the viewport tag and it fixed the issue. Below is my current viewport tag:

<meta name="viewport" content="user-scalable=0;"/>

I don't understand -Wl,-rpath -Wl,

One other thing. You may need to specify the -L option as well - eg

-Wl,-rpath,/path/to/foo -L/path/to/foo -lbaz

or you may end up with an error like

ld: cannot find -lbaz

Remove a specific character using awk or sed

tr can be more concise for removing characters than sed or awk, especially when you want to remove different characters from a string.

Removing double quotes:

echo '"Hi"' | tr -d \"
# Produces Hi without quotes

Removing different kinds of brackets:

echo '[{Hi}]' | tr -d {}[]
# Produces Hi without brackets

-d stands for "delete".

Jquery Open in new Tab (_blank)

window.location always refers to the location of the current window. Changing it will affect only the current window.

One thing that can be done is forcing a click on the link after setting its target attribute to _blank:

Check this:

Disclaimer: Its my blog.

INSERT statement conflicted with the FOREIGN KEY constraint - SQL Server

It means exactly what it says. You're trying to insert a value into a column that has a FK constraint on it that doesn't match any values in the lookup table.

"android.view.WindowManager$BadTokenException: Unable to add window" on

Try this :

    public class <class> extends Activity{

    private AlertDialog.Builder builder;

    public void onCreate(Bundle savedInstanceState) {


                builder = new AlertDialog.Builder(<class>.this);

        //call the <className> class to execute

    private class <className> extends AsyncTask<String, Void, String>{

    protected String doInBackground(String... params) {

    protected void onPostExecute(String result){
        if(page.contains("error")) //when not subscribed
                builder.setNeutralButton("Ok",new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int whichButton){
                        String pl = ""; 

                        mHelper.<flow>(<class>.this, SKU, RC_REQUEST, 
                        <listener>, pl);

                        catch(Exception e)



How to modify a text file?

The fileinput module of the Python standard library will rewrite a file inplace if you use the inplace=1 parameter:

import sys
import fileinput

# replace all occurrences of 'sit' with 'SIT' and insert a line after the 5th
for i, line in enumerate(fileinput.input('lorem_ipsum.txt', inplace=1)):
    sys.stdout.write(line.replace('sit', 'SIT'))  # replace 'sit' and write
    if i == 4: sys.stdout.write('\n')  # write a blank line after the 5th line

If else on WHERE clause

Note the following is functionally different to Gordon Linoff's answer. His answer assumes that you want to use email2 if email is NULL. Mine assumes you want to use email2 if email is an empty-string. The correct answer will depend on your database (or you could perform a NULL check and an empty-string check - it all depends on what is appropriate for your database design).

SELECT  `id` ,  `naam` 
FROM  `klanten` 
WHERE `email` LIKE  '%[email protected]%'
OR (LENGTH(email) = 0 AND `email2` LIKE  '%[email protected]%')

jquery 3.0 url.indexOf error

I came across the same error after updating to the latest version of JQuery. Therefore I updated the jquery file I was working on, as stated in a previous answer, so it said .on("load") instead of .load().

This fix isn't very stable and sometimes it didn't work for me. Therefore to fix this issue you should update your code from:




I got this fix from the following source:

Getting URL parameter in java and extract a specific text from that URL

Import these libraries

import org.apache.http.NameValuePair;
import org.apache.http.message.BasicNameValuePair;

Similar to the verisimilitude, but with the capabilities of handling multivalue parameters. Note: I've seen HTTP GET requests without a value, in this case the value will be null.

public static List<NameValuePair> getQueryMap(String query)  
    List<NameValuePair> queryMap = new ArrayList<NameValuePair>();
    String[] params = query.split(Pattern.quote("&"));  
    for (String param : params)
        String[] chunks = param.split(Pattern.quote("="));
        String name = chunks[0], value = null;  
        if(chunks.length > 1) {
            value = chunks[1];
        queryMap.add(new BasicNameValuePair(name, value));
    return queryMap;


GET /bottom.gif?e235c08=1509896923&%49%6E%...

Check if a div does NOT exist with javascript

getElementById returns null if there is no such element.

How to split an integer into an array of digits?

[int(i) for i in str(number)]

or, if do not want to use a list comprehension or you want to use a base different from 10

from __future__ import division # for compatibility of // between Python 2 and 3
def digits(number, base=10):
    assert number >= 0
    if number == 0:
        return [0]
    l = []
    while number > 0:
        l.append(number % base)
        number = number // base
    return l

Is there a way to do repetitive tasks at intervals?

If you want to stop it in any moment ticker

ticker := time.NewTicker(500 * time.Millisecond)
go func() {
    for range ticker.C {
time.Sleep(1600 * time.Millisecond)

If you do not want to stop it tick:

tick := time.Tick(500 * time.Millisecond)
for range tick {

Error:Execution failed for task ':app:transformClassesWithJarMergingForDebug'

Use project root in terminal like this:-/Users/rajnish/Desktop/RankProjects/ProjectCloud

After that enter this command ./gradlew clean

It will work.

Representing EOF in C code?

The value of EOF can't be confused with any real character.

If a= getchar(), then we must declare a big enough to hold any value that getchar() returns. We can't use char since a must be big enough to hold EOF in addition to characters.

Removing page title and date when printing web page (with CSS?)

Try this;

@media print{ @page { margin-top: 30px; margin-bottom: 30px;}}

Random String Generator Returning Same String

I added the option to choose the length using the Ranvir solution

public static string GenerateRandomString(int length)
            string randomString= string.Empty;

            while (randomString.Length <= length)
                randomString+= Path.GetRandomFileName();
                randomString= randomString.Replace(".", string.Empty);

            return randomString.Substring(0, length);

Removing character in list of strings

A faster way is to join the list, replace 8 and split the new string:

mylist = [("aaaa8"),("bb8"),("ccc8"),("dddddd8")]
mylist = ' '.join(mylist).replace('8','').split()
print mylist

What jsf component can render a div tag?

In JSF 2.2 it's possible to use passthrough elements:

<html xmlns=""
    <div jsf:id="id1" />

The requirement is to have at least one attribute in the element using jsf namespace.

How to import a SQL Server .bak file into MySQL?

In this problem, the answer is not updated in a timely. So it's happy to say that in 2020 Migrating to MsSQL into MySQL is that much easy. An online converter like RebaseData will do your job with one click. You can just upload your .bak file which is from MsSQL and convert it into .sql format which is readable to MySQL.

Additional note: This can not only convert your .bak files but also this site is for all types of Database migrations that you want.

How to call a vue.js function on page load

If you get data in array you can do like below. It's worked for me

    {{ id }}

    import axios from "axios";

        export default {
            name: 'HelloWorld',
            data () {
                return {
                    id: "",

    mounted() {
                axios({ method: "GET", "url": "https://localhost:42/api/getdata" }).then(result => {
                }, error => {

Ajax - 500 Internal Server Error

One must use behavior: JsonRequestBehavior.AllowGet in Post Json Return in C#

How to use "not" in xpath?

you can use not(expression) function


expression != true()

grabbing first row in a mysql query only

You didn't specify how the order is determined, but this will give you a rank value in MySQL:

       @rownum := @rownum +1 AS rank
  JOIN (SELECT @rownum := 0) r
 WHERE = 'sarmen'

Then you can pick out what rows you want, based on the rank value.

Mark error in form using Bootstrap

(UPDATED with examples for Bootstrap v4, v3 and v3)

Examples of forms with validation classes for the past few major versions of Bootstrap.

Bootstrap v4

See the live version on codepen

bootstrap v4 form validation

<div class="container">
    <div class="form-group row">
      <label for="inputEmail" class="col-sm-2 col-form-label text-success">Email</label>
      <div class="col-sm-7">
        <input type="email" class="form-control is-valid" id="inputEmail" placeholder="Email">

    <div class="form-group row">
      <label for="inputPassword" class="col-sm-2 col-form-label text-danger">Password</label>
      <div class="col-sm-7">
        <input type="password" class="form-control is-invalid" id="inputPassword" placeholder="Password">
      <div class="col-sm-3">
        <small id="passwordHelp" class="text-danger">
          Must be 8-20 characters long.

Bootstrap v3

See the live version on codepen

bootstrap v3 form validation

<form role="form">
  <div class="form-group has-warning">
    <label class="control-label" for="inputWarning">Input with warning</label>
    <input type="text" class="form-control" id="inputWarning">
    <span class="help-block">Something may have gone wrong</span>
  <div class="form-group has-error">
    <label class="control-label" for="inputError">Input with error</label>
    <input type="text" class="form-control" id="inputError">
    <span class="help-block">Please correct the error</span>
  <div class="form-group has-info">
    <label class="control-label" for="inputError">Input with info</label>
    <input type="text" class="form-control" id="inputError">
    <span class="help-block">Username is taken</span>
  <div class="form-group has-success">
    <label class="control-label" for="inputSuccess">Input with success</label>
    <input type="text" class="form-control" id="inputSuccess" />
    <span class="help-block">Woohoo!</span>

Bootstrap v2

See the live version on jsfiddle

bootstrap v2 form validation

The .error, .success, .warning and .info classes are appended to the .control-group. This is standard Bootstrap markup and styling in v2. Just follow that and you're in good shape. Of course you can go beyond with your own styles to add a popup or "inline flash" if you prefer, but if you follow Bootstrap convention and hang those validation classes on the .control-group it will stay consistent and easy to manage (at least since you'll continue to have the benefit of Bootstrap docs and examples)

  <form class="form-horizontal">
    <div class="control-group warning">
      <label class="control-label" for="inputWarning">Input with warning</label>
      <div class="controls">
        <input type="text" id="inputWarning">
        <span class="help-inline">Something may have gone wrong</span>
    <div class="control-group error">
      <label class="control-label" for="inputError">Input with error</label>
      <div class="controls">
        <input type="text" id="inputError">
        <span class="help-inline">Please correct the error</span>
    <div class="control-group info">
      <label class="control-label" for="inputInfo">Input with info</label>
      <div class="controls">
        <input type="text" id="inputInfo">
        <span class="help-inline">Username is taken</span>
    <div class="control-group success">
      <label class="control-label" for="inputSuccess">Input with success</label>
      <div class="controls">
        <input type="text" id="inputSuccess">
        <span class="help-inline">Woohoo!</span>

MySql with JAVA error. The last packet sent successfully to the server was 0 milliseconds ago

Try the following suggestions:

  1. Your machine may have a static IP; map this IP to the hosts file as localhost.
  2. Try to log in from your computer or within the network via mysql command; if login is successful, it means that MySQL runs fine.

AngularJS : Custom filters and ng-repeat

One of the easiest ways to fix this is to use the $ which is the search all.

Here is a plunker that shows it working. I have changed the checkboxes to radio ( because I thought they should be complementary )..

If you want a very specific way of doing this ( instead of doing a generic search ) you need work with functions in the search.

The documentation is here

Java 8 stream's .min() and .max(): why does this compile?

Let me explain what is happening here, because it isn't obvious!

First, Stream.max() accepts an instance of Comparator so that items in the stream can be compared against each other to find the minimum or maximum, in some optimal order that you don't need to worry too much about.

So the question is, of course, why is Integer::max accepted? After all it's not a comparator!

The answer is in the way that the new lambda functionality works in Java 8. It relies on a concept which is informally known as "single abstract method" interfaces, or "SAM" interfaces. The idea is that any interface with one abstract method can be automatically implemented by any lambda - or method reference - whose method signature is a match for the one method on the interface. So examining the Comparator interface (simple version):

public Comparator<T> {
    T compare(T o1, T o2);

If a method is looking for a Comparator<Integer>, then it's essentially looking for this signature:

int xxx(Integer o1, Integer o2);

I use "xxx" because the method name is not used for matching purposes.

Therefore, both Integer.min(int a, int b) and Integer.max(int a, int b) are close enough that autoboxing will allow this to appear as a Comparator<Integer> in a method context.

Magento: get a static block as html in a phtml file

In the layout (app/design/frontend/your_theme/layout/default.xml):

    <cms_page> <!-- need to be redefined for your needs -->
        <reference name="content">
            <block type="cms/block" name="cms_newest_product" as="cms_newest_product">
                <action method="setBlockId"><block_id>newest_product</block_id></action>

In your phtml template:

<?php echo $this->getChildHtml('newest_product'); ?>

Don't forget about cache cleaning.

I think it help.

How to position a div in the middle of the screen when the page is bigger than the screen

Try this one.

.centered {
  position: fixed;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);

Android studio Error "Unsupported Modules Detected: Compilation is not supported for following modules"

Try this steps Individually:-

1) Go to File->Invalidate Caches / Restart.

2) Close android studio, Go to C:\Users\(Your UserName)\.AndroidStudio(version)\system and delete caches folder.

If till now nothing worked, then this step will definitely work...

3) Simply change project location and import project with new location.

Enjoy :-):-)

Is Xamarin free in Visual Studio 2015?

If you go to the Visual Studio 2015 RC cross-platform and mobile apps page, then read and scroll to the bottom, it appears that Microsoft is including Xamarin, and upon installing it you do have, as James said, the Xamarin Starter edition. In 2015 RC go to Tools, Xamarin Account to see your Xamarin license. I do not know the limitations, or any expiration date, of this Starter Xamarin Account.

Still, I don't know about you, but the Visual Studio 2015 RC "Community" edition I installed expires in less than 180 days. (Check the Help menu, go to "About...", and click on your license status to check.)

Let's say Xamarin Starter edition is free, but Visual Studio 2015 "Community" has an expiration date. So the bigger question might be whether Visual Studio 2015 "Community" will be free.

Without Xamarin though, Microsoft is offering C++ tools for cross-platform development, but scroll down to the bottom of the page and you might be surprised or confused at the download link description.

How can I get a Unicode character's code?

In Java, char is technically a "16-bit integer", so you can simply cast it to int and you'll get it's code. From Oracle:

The char data type is a single 16-bit Unicode character. It has a minimum value of '\u0000' (or 0) and a maximum value of '\uffff' (or 65,535 inclusive).

So you can simply cast it to int.

char registered = '®';
System.out.println(String.format("This is an int-code: %d", (int) registered));
System.out.println(String.format("And this is an hexa code: %x", (int) registered));

Convert pandas dataframe to NumPy array

A Simpler Way for Example DataFrame:


         gbm       nnet        reg
0  12.097439  12.047437  12.100953
1  12.109811  12.070209  12.095288
2  11.720734  11.622139  11.740523
3  11.824557  11.926414  11.926527
4  11.800868  11.727730  11.729737
5  12.490984  12.502440  12.530894




array([[(0, 12.097439  , 12.047437, 12.10095324),
        (1, 12.10981081, 12.070209, 12.09528824),
        (2, 11.72073428, 11.622139, 11.74052253),
        (3, 11.82455653, 11.926414, 11.92652727),
        (4, 11.80086775, 11.72773 , 11.72973699),
        (5, 12.49098389, 12.50244 , 12.53089367)]],
dtype=(numpy.record, [('index', '<i8'), ('gbm', '<f8'), ('nnet', '<f4'),
       ('reg', '<f8')]))

How to detect reliably Mac OS X, iOS, Linux, Windows in C preprocessor?

There are predefined macros that are used by most compilers, you can find the list here. GCC compiler predefined macros can be found here. Here is an example for gcc:

#if defined(WIN32) || defined(_WIN32) || defined(__WIN32__) || defined(__NT__)
   //define something for Windows (32-bit and 64-bit, this part is common)
   #ifdef _WIN64
      //define something for Windows (64-bit only)
      //define something for Windows (32-bit only)
#elif __APPLE__
    #include <TargetConditionals.h>
         // iOS Simulator
        // iOS device
    #elif TARGET_OS_MAC
        // Other kinds of Mac OS
    #   error "Unknown Apple platform"
#elif __linux__
    // linux
#elif __unix__ // all unices not caught above
    // Unix
#elif defined(_POSIX_VERSION)
    // POSIX
#   error "Unknown compiler"

The defined macros depend on the compiler that you are going to use.

The _WIN64 #ifdef can be nested into the _WIN32 #ifdef because _WIN32 is even defined when targeting the Windows x64 version. This prevents code duplication if some header includes are common to both (also WIN32 without underscore allows IDE to highlight the right partition of code).

Python - Locating the position of a regex match in a string?

I don't think this question has been completely answered yet because all of the answers only give single match examples. The OP's question demonstrates the nuances of having 2 matches as well as a substring match which should not be reported because it is not a word/token.

To match multiple occurrences, one might do something like this:

iter = re.finditer(r"\bis\b", String)
indices = [m.start(0) for m in iter]

This would return a list of the two indices for the original string.

What is a 'Closure'?

A simple example in Groovy for your reference:

def outer() {
    def x = 1
    return { -> println(x)} // inner
def innerObj = outer()
innerObj() // prints 1

How can I use a local image as the base image with a dockerfile?

Remember to put not only the tag but also the repository in which that tag is, this way:

docker images
REPOSITORY                                TAG                       IMAGE ID            CREATED             SIZE
elixir                                    1.7-centos7_3             e15e6bf57262        20 hours ago        925MB

You should reference it this way:


Using a string variable as a variable name

You can use exec for that:

>>> foo = "bar"
>>> exec(foo + " = 'something else'")
>>> print bar
something else

How to write and save html file in python?

As others have mentioned, use triple quotes ”””abc””” for multiline strings. Also, you can do this without having to call close() using the with keyword. For example:

# HTML String
html = """
<table border=1>
     <% for i in range(10): %>
         <td><%= i %></td>
         <td><%= i**2 %></td>

# Write HTML String to file.html
with open("file.html", "w") as file:

See for more details on the with keyword in Python.

How to get resources directory path programmatically



File folder = new ClassPathResource("sql").getFile();
File[] listOfFiles = folder.listFiles();

It is worth noting that this will limit your deployment options, ClassPathResource.getFile() only works if the container has exploded (unzipped) your war file.

What does -save-dev mean in npm install grunt --save-dev

Documentation from npm for npm install <package-name> --save and npm install <package-name> --save-dev can be found here:

A package.json file declares metadata about the module you are developing. Both aforementioned commands modify this package.json file. --save will declare the installed package (in this case, grunt) as a dependency for your module; --save-dev will declare it as a dependency for development of your module.

Ask yourself: will the installed package be required for use of my module, or will it only be required for developing it?

Convert Data URI to File then append to FormData

The evolving standard looks to be canvas.toBlob() not canvas.getAsFile() as Mozilla hazarded to guess.

I don't see any browser yet supporting it :(

Thanks for this great thread!

Also, anyone trying the accepted answer should be careful with BlobBuilder as I'm finding support to be limited (and namespaced):

    var bb;
    try {
        bb = new BlobBuilder();
    } catch(e) {
        try {
            bb = new WebKitBlobBuilder();
        } catch(e) {
            bb = new MozBlobBuilder();

Were you using another library's polyfill for BlobBuilder?

Simple Java Client/Server Program

If you got your IP address from an external web site (, you have your external IP address. If your server is on the same local network, you may need an internal IP address instead. Local IP addresses look like 10.X.X.X, 172.X.X.X, or 192.168.X.X.

Try the suggestions on this page to find what your machine thinks its IP address is.

How to use RecyclerView inside NestedScrollView?

I had to implement CoordinatorLayout with toolbar scrolling and it just took me all the day messing around this. I've got it working by removing NestedScrollView at all. So I'm just using RelativeLayout at the root.

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android=""

            app:layout_behavior="@string/appbar_scrolling_view_behavior" />


Format XML string to print friendly XML string

You will have to parse the content somehow ... I find using LINQ the most easy way to do it. Again, it all depends on your exact scenario. Here's a working example using LINQ to format an input XML string.

string FormatXml(string xml)
         XDocument doc = XDocument.Parse(xml);
         return doc.ToString();
     catch (Exception)
         // Handle and throw if fatal exception here; don't just ignore them
         return xml;

[using statements are ommitted for brevity]

How to set button click effect in Android?

For all the views


But for cardview which has elevation use


For Circular click effect as in toolbar


Also you need to set


Overlaying a DIV On Top Of HTML 5 Video

<div id="video_box">
  <div id="video_overlays"></div>
    <video id="player" src="" type="video/webm" onclick=";">Your browser does not support this streaming content.</video>

for this you need to just add css like this:

#video_overlays {
  position: absolute;
  background-color: rgba(0, 0, 0, 0.46);
  z-index: 2;
  left: 0;
  right: 0;
  top: 0;
  bottom: 0;
#video_box{position: relative;}

How to add local .jar file dependency to build.gradle file?

The solution which worked for me is the usage of fileTree in build.gradle file. Keep the .jar which need to add as dependency in libs folder. The give the below code in dependenices block in build.gradle:

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])

git returns http error 407 from proxy after CONNECT

What worked for me is something similar to what rohitmohta is proposing ; in regular DOS command prompt (not on git bash) :


git config --global http.proxy http://username:password@proxiURL:proxiPort

and in some cases also

git config --global https.proxy http://username:password@proxiURL:proxiPort


git config --global http.sslVerify false

(I confirm it's necessary : if set to true getting "SSL certificate problem: unable to get local issuer certificate" error)

in my case, no need of defining all_proxy variable

and finally

git clone

Javascript getElementById based on a partial string

querySelectorAll with modern enumeration

polls = document.querySelectorAll('[id ^= "poll-"]');, callback);

function callback(element, iterator) {

The first line selects all elements which id starts with the string poll-. The second line evokes the enumeration and a callback function.

Set port for php artisan.php serve

you can also add host as well with same command like :

php artisan serve --host= --port=8080

Get value of div content using jquery

Use .text() to extract the content of the div

var text = $('#field-function_purpose').text()

How to Fill an array from user input C#?

of course....Console.ReadLine always return you have to convert type string to double


Change the selected value of a drop-down list with jQuery

Just try with


and not with


How to convert a byte array to a hex string in Java?

I usually use the following method for debuf statement, but i don't know if it is the best way of doing it or not

private static String digits = "0123456789abcdef";

public static String toHex(byte[] data){
    StringBuffer buf = new StringBuffer();
    for (int i = 0; i != data.length; i++)
        int v = data[i] & 0xff;
        buf.append(digits.charAt(v >> 4));
        buf.append(digits.charAt(v & 0xf));
    return buf.toString();

Unable to load config info from /usr/local/ssl/openssl.cnf on Windows

The only thing that worked for me in this situation was the self-created openssl.cnf file.

Here are the basics needed for this exercise (edit as needed):

# OpenSSL configuration file.

# Establish working directory.

dir                         = .

[ ca ]
default_ca                  = CA_default

[ CA_default ]
serial                      = $dir/serial
database                    = $dir/certindex.txt
new_certs_dir               = $dir/certs
certificate                 = $dir/cacert.pem
private_key                 = $dir/private/cakey.pem
default_days                = 365
default_md                  = md5
preserve                    = no
email_in_dn                 = no
nameopt                     = default_ca
certopt                     = default_ca
policy                      = policy_match

[ policy_match ]
countryName                 = match
stateOrProvinceName         = match
organizationName            = match
organizationalUnitName      = optional
commonName                  = supplied
emailAddress                = optional

[ req ]
default_bits                = 1024          # Size of keys
default_keyfile             = key.pem       # name of generated keys
default_md                  = md5               # message digest algorithm
string_mask                 = nombstr       # permitted characters
distinguished_name          = req_distinguished_name
req_extensions              = v3_req

[ req_distinguished_name ]
# Variable name             Prompt string
#-------------------------    ----------------------------------
0.organizationName          = Organization Name (company)
organizationalUnitName      = Organizational Unit Name (department, division)
emailAddress                = Email Address
emailAddress_max            = 40
localityName                = Locality Name (city, district)
stateOrProvinceName         = State or Province Name (full name)
countryName                 = Country Name (2 letter code)
countryName_min             = 2
countryName_max             = 2
commonName                  = Common Name (hostname, IP, or your name)
commonName_max              = 64

# Default values for the above, for consistency and less typing.
# Variable name             Value
#------------------------     ------------------------------
0.organizationName_default  = My Company
localityName_default        = My Town
stateOrProvinceName_default = State or Providence
countryName_default         = US

[ v3_ca ]
basicConstraints            = CA:TRUE
subjectKeyIdentifier        = hash
authorityKeyIdentifier      = keyid:always,issuer:always

[ v3_req ]
basicConstraints            = CA:FALSE
subjectKeyIdentifier        = hash

I hope that helps.

glm rotate usage in Opengl

GLM has good example of rotation :

glm::mat4 Projection = glm::perspective(45.0f, 4.0f / 3.0f, 0.1f, 100.f);
glm::mat4 ViewTranslate = glm::translate(
    glm::vec3(0.0f, 0.0f, -Translate)
glm::mat4 ViewRotateX = glm::rotate(
    glm::vec3(-1.0f, 0.0f, 0.0f)
glm::mat4 View = glm::rotate(
    glm::vec3(0.0f, 1.0f, 0.0f)
glm::mat4 Model = glm::scale(
glm::mat4 MVP = Projection * View * Model;
glUniformMatrix4fv(LocationMVP, 1, GL_FALSE, glm::value_ptr(MVP));

Create a File object in memory from a string in Java

FileReader r = new FileReader(file);

Use a file reader load the file and then write its contents to a string buffer.


The link above shows you an example of how to accomplish this. As other post to this answer say to load a file into memory you do not need write access as long as you do not plan on making changes to the actual file.

How to check if a view controller is presented modally or pushed on a navigation stack?

self.navigationController != nil would mean it's in a navigation stack.

In order to handle the case that the current view controller is pushed while the navigation controller is presented modally, I have added some lines of code to check if the current view controller is the root controller in the navigation stack .

extension UIViewController {
    var isModal: Bool {
        if let index = navigationController?.viewControllers.firstIndex(of: self), index > 0 {
            return false
        } else if presentingViewController != nil {
            return true
        } else if let navigationController = navigationController, navigationController.presentingViewController?.presentedViewController == navigationController {
            return true
        } else if let tabBarController = tabBarController, tabBarController.presentingViewController is UITabBarController {
            return true
        } else {
            return false

How to add Options Menu to Fragment in Android

In your menu folder make a .menu xml file and add this xml

    app:showAsAction="always|collapseActionView" />

In your fragment class overide this method and

implement SearchView.OnQueryTextListener    in your fragment class

 public void onViewCreated(View view, Bundle savedInstanceState) {    
  super.onViewCreated(view, savedInstanceState);


Now just setup your menu xml file in fragment class

public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
    inflater.inflate(, menu);

    final MenuItem item = menu.findItem(;
    final SearchView searchView = (SearchView)    

            new MenuItemCompat.OnActionExpandListener() {
                public boolean onMenuItemActionCollapse(MenuItem item) {
                    // Do something when collapsed

                    return true; // Return true to collapse action view

                public boolean onMenuItemActionExpand(MenuItem item) {
                    // Do something when expanded
                    return true; // Return true to expand action view


Visual Studio displaying errors even if projects build

My symptoms in VS2019 were that I would build with some errors. Then I'd fix the errors, and the build would work, as shown in the Output window. But the Errors windows still showed the old errors. I could run it just fine. Closing VS2019 and reopneing fixed the issue, but only for a little while. This started happening on version 16.4.3

This solution seems to work for me:

Uncheck Tools->Option->Projects and Solutions->General->Allow parallel project initialization

I found this fix buried way down in the comments here:

ASP.NET Core return JSON with status code

Awesome answers I found here and I also tried this return statement see StatusCode(whatever code you wish) and it worked!!!

return Ok(new {
                    Token = new JwtSecurityTokenHandler().WriteToken(token),
                    Expiration = token.ValidTo,
                    username = user.FullName,
                    StatusCode = StatusCode(200)

How to pass a variable from Activity to Fragment, and pass it back?

Sending data from Activity into Fragments linked by XML

If you create a fragment in Android Studio using one of the templates e.g. File > New > Fragment > Fragment (List), then the fragment is linked via XML. The newInstance method is created in the fragment but is never called so can't be used to pass arguments.

Instead in the Activity override the method onAttachFragment

public void onAttachFragment(Fragment fragment) {
    if (fragment instanceof DetailsFragment) {
        Bundle args = new Bundle();
        args.putInt("index", index);

Then read the arguments in the fragment onCreate method as per the other answers

How do I use the includes method in lodash to check if an object is in the collection?

Supplementing the answer by p.s.w.g, here are three other ways of achieving this using lodash 4.17.5, without using _.includes():

Say you want to add object entry to an array of objects numbers, only if entry does not exist already.

let numbers = [
    { to: 1, from: 2 },
    { to: 3, from: 4 },
    { to: 5, from: 6 },
    { to: 7, from: 8 },
    { to: 1, from: 2 } // intentionally added duplicate

let entry = { to: 1, from: 2 };

 * 1. This will return the *index of the first* element that matches:
_.findIndex(numbers, (o) => { return _.isMatch(o, entry) });
// output: 0

 * 2. This will return the entry that matches. Even if the entry exists
 *    multiple time, it is only returned once.
_.find(numbers, (o) => { return _.isMatch(o, entry) });
// output: {to: 1, from: 2}

 * 3. This will return an array of objects containing all the matches.
 *    If an entry exists multiple times, if is returned multiple times.
_.filter(numbers, _.matches(entry));
// output: [{to: 1, from: 2}, {to: 1, from: 2}]

If you want to return a Boolean, in the first case, you can check the index that is being returned:

_.findIndex(numbers, (o) => { return _.isMatch(o, entry) }) > -1;
// output: true

How to actually search all files in Visual Studio

Press Ctrl+,

Then you will see a docked window under name of "Go to all"

This a picture of the "Go to all" in my IDE


How to inject a Map using the @Value Spring Annotation?

You can inject .properties as a map in your class using @Resource annotation.

If you are working with XML based configuration, then add below bean in your spring configuration file:

 <bean id="myProperties" class="org.springframework.beans.factory.config.PropertiesFactoryBean">
      <property name="location" value=""/>

For, Annotation based:

@Bean(name = "myProperties")
public static PropertiesFactoryBean mapper() {
        PropertiesFactoryBean bean = new PropertiesFactoryBean();
        bean.setLocation(new ClassPathResource(
        return bean;

Then you can pick them up in your application as a Map:

@Resource(name = "myProperties")
private Map<String, String> myProperties;

How to add custom method to Spring Data JPA

Im using the following code in order to access generated find methods from my custom implementation. Getting the implementation through the bean factory prevents circular bean creation problems.

public class MyRepositoryImpl implements MyRepositoryExtensions, BeanFactoryAware {

    private BrandRepository myRepository;

    public MyBean findOne(int first, int second) {
        return myRepository.findOne(new Id(first, second));

    public void setBeanFactory(BeanFactory beanFactory) throws BeansException {
        myRepository = beanFactory.getBean(MyRepository.class);