Programs & Examples On #Miniport

Enabling/Disabling Microsoft Virtual WiFi Miniport

In my case I had to uninstall and reinstall the wireless adapter driver to be able to execute the command

How to manage a redirect request after a jQuery Ajax call

If you also want to pass the values then you can also set the session variables and access Eg: In your jsp you can write

<% HttpSession ses = request.getSession(true);
   String temp=request.getAttribute("what_you_defined"); %>

And then you can store this temp value in your javascript variable and play around

Printing chars and their ASCII-code in C

Simplest approach in printing ASCII values of a given alphabet.

Here is an example :

int main()
    //we are printing the ASCII value of 'a'
    char a ='a'
    return 0;

What is the difference between single-quoted and double-quoted strings in PHP?

A single-quoted string does not have variables within it interpreted. A double-quoted string does.

Also, a double-quoted string can contain apostrophes without backslashes, while a single-quoted string can contain unescaped quotation marks.

The single-quoted strings are faster at runtime because they do not need to be parsed.

PostgreSQL IF statement

Just to help if anyone stumble on this question like me, if you want to use if in PostgreSQL, you use "CASE"

        when stage = 1 then 'running'
        when stage = 2 then 'done'
        when stage = 3 then 'stopped'
        'not running'
    end as run_status from processes

Fit cell width to content

Simple :

    <div style='overflow-x:scroll;overflow-y:scroll;width:100%;height:100%'>

nodejs module.js:340 error: cannot find module

Try npm install --production and then npm start.

How to store an array into mysql?

I'd prefer to normalize your table structure more, something like;

id (pk)

id (pk)

commentId (pk)
userId (pk)
rating (float)

Now it's easier to maintain! And MySQL only accept one vote per user and comment.

Segmentation Fault - C

Even better

#include <stdio.h>
  char *line = NULL;
  size_t count;
  char *dup_line;

  getline(&line,&count, stdin);



  return 0;

Test if executable exists in Python?

See os.path module for some useful functions on pathnames. To check if an existing file is executable, use os.access(path, mode), with the os.X_OK mode.


Value to include in the mode parameter of access() to determine if path can be executed.

EDIT: The suggested which() implementations are missing one clue - using os.path.join() to build full file names.

Git: How to remove proxy

Some times, local config command won't show the proxy but it wont allow git push due to proxy. Run the following commands within the directory and see.

#git config --local --list

But the following commands displays the proxy set to local repository:

#git config http.proxy
#git config https.proxy

If the above command displays any proxy then clear it by running the following commands:

#git config https.proxy ""
#git config https.proxy ""

whitespaces in the path of windows filepath

Try putting double quotes in your filepath variable

"\"E:/ABC/SEM 2/testfiles/all.txt\""

Check the permissions of the file or in any case consider renaming the folder to remove the space

nginx missing sites-available directory

If you'd prefer a more direct approach, one that does NOT mess with symlinking between /etc/nginx/sites-available and /etc/nginx/sites-enabled, do the following:

  1. Locate your nginx.conf file. Likely at /etc/nginx/nginx.conf
  2. Find the http block.
  3. Somewhere in the http block, write include /etc/nginx/conf.d/*.conf; This tells nginx to pull in any files in the conf.d directory that end in .conf. (I know: it's weird that a directory can have a . in it.)
  4. Create the conf.d directory if it doesn't already exist (per the path in step 3). Be sure to give it the right permissions/ownership. Likely root or www-data.
  5. Move or copy your separate config files (just like you have in /etc/nginx/sites-available) into the directory conf.d.
  6. Reload or restart nginx.
  7. Eat an ice cream cone.

Any .conf files that you put into the conf.d directory from here on out will become active as long as you reload/restart nginx after.

Note: You can use the conf.d and sites-enabled + sites-available method concurrently if you wish. I like to test on my dev box using conf.d. Feels faster than symlinking and unsymlinking.

How to set entire application in portrait mode only?

Yes you can do this both programmatically and for all your activities making an AbstractActivity that all your activities extends.

public abstract class AbstractActivity extends Activity {
    protected void onCreate(Bundle savedInstanceState) {
        setRequestedOrientation (ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);

This abstract activity can also be used for a global menu.

LaTex left arrow over letter in math mode

Use \overleftarrow to create a long arrow to the left.


LaTeX output

How to insert image in mysql database(table)?

Step 1: open your mysql workbench application select table. choose image cell right click select "Open value in Editor" enter image description here

Step 2: click on the load button and choose image file enter image description here

Step 3:then click apply buttonenter image description here

Step 4: Then apply the query to save the image .Don't forgot image data type is "BLOB". Step 5: You can can check uploaded image enter image description here

How to Merge Two Eloquent Collections?

Merge two different eloquent collections into one and some objects happen to have the same id, one will overwrite the other. Use push() method instead or rethink your approach to the problem to avoid that. Refer to web

How to retrieve checkboxes values in jQuery

Anyway, you probably need something like this:

 var val = $('#c_b :checkbox').is(':checked').val();
 $('#t').val( val );

This will get the value of the first checked checkbox on the page and insert that in the textarea with id='textarea'.

Note that in your example code you should put the checkboxes in a form.

Laravel, sync() - how to sync an array and also pass additional pivot fields?

This works for me

foreach ($photos_array as $photo) {

    //collect all inserted record IDs
    $photo_id_array[$photo->id] = ['type' => 'Offence'];  


//Insert into offence_photo table
$offence->photos()->sync($photo_id_array, false);//dont delete old entries = false

How to resolve Nodejs: Error: ENOENT: no such file or directory

I solved this error by simply creating a blank file at that location for which I got the error. If you are getting the error for a directory, You can try by creating empty directory also. All the best.

What steps are needed to stream RTSP from FFmpeg?

Another streaming command I've had good results with is piping the ffmpeg output to vlc to create a stream. If you don't have these installed, you can add them:

sudo apt install vlc ffmpeg

In the example I use an mpeg transport stream (ts) over http, instead of rtsp. I've tried both, but the http ts stream seems to work glitch-free on my playback devices.

I'm using a video capture HDMI>USB device that sets itself up on the video4linux2 driver as input. Piping through vlc must be CPU-friendly, because my old dual-core Pentium CPU is able to do the real-time encoding with no dropped frames. I've also had audio-sync issues with some of the other methods, where this method always has perfect audio-sync.

You will have to adjust the command for your device or file. If you're using a file as input, you won't need all that v4l2 and alsa stuff. Here's the ffmpeg|vlc command:

ffmpeg -thread_queue_size 1024 -f video4linux2 -input_format mjpeg -i /dev/video0 -r 30 -f alsa -ac 1 -thread_queue_size 1024 -i hw:1,0 -acodec aac -vcodec libx264 -preset ultrafast -crf 18 -s hd720 -vf format=yuv420p -profile:v main -threads 0 -f mpegts -|vlc -I dummy - --sout='#std{access=http,mux=ts,dst=:8554}'

For example, lets say your server PC IP is, then the stream can be played by this command:


How to return 2 values from a Java method?

In my opinion the best is to create a new class which constructor is the function you need, e.g.:

public class pairReturn{
        //name your parameters:
        public int sth1;
        public double sth2;
        public pairReturn(int param){
            //place the code of your function, e.g.:

Then simply use the constructor as you would use the function:

pairReturn pR = new pairReturn(15);

and you can use pR.sth1, pR.sth2 as "2 results of the function"

What is the javascript filename naming convention?

One possible naming convention is to use something similar to the naming scheme jQuery uses. It's not universally adopted but it is pretty common.


where the product-name + plugin pair can also represent a namespace and a module. The version and filetype are usually optional.

filetype can be something relative to how the content of the file is. Often seen are:

  • min for minified files
  • custom for custom built or modified files


  • jquery-1.4.2.min.js
  • jquery.plugin-0.1.js
  • myapp.invoice.js

Lowercase and Uppercase with jQuery

If it's just for display purposes, you can render the text as upper or lower case in pure CSS, without any Javascript using the text-transform property:

.myclass {
    text-transform: lowercase;

See for more info.

However, note that this doesn't actually change the value to lower case; it just displays it that way. This means that if you examine the contents of the element (ie using Javascript), it will still be in its original format.

Get refresh token google api

Since March 2016, use prompt=consent to regenerate Google API refresh token.

As mentioned in,

approval_prompt=force has been replaced with prompt=none|consent|select_account

How can I check if a directory exists?

You may also use access in combination with opendir to determine if the directory exists, and, if the name exists, but is not a directory. For example:

/* test that dir exists (1 success, -1 does not exist, -2 not dir) */
xis_dir (const char *d)
    DIR *dirptr;

    if (access ( d, F_OK ) != -1 ) {
        // file exists
        if ((dirptr = opendir (d)) != NULL) {
            closedir (dirptr); /* d exists and is a directory */
        } else {
            return -2; /* d exists but is not a directory */
    } else {
        return -1;     /* d does not exist */

    return 1;

How can labels/legends be added for all chart types in chart.js (

You can include a legend template in the chart options:

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

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

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

  //and append it to your page somewhere

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

How to use: while not in

In your case, ('AND' and 'OR' and 'NOT') evaluates to "NOT", which may or may not be in your list...

while 'AND' not in MyList and 'OR' not in MyList and 'NOT' not in MyList:
    print 'No Boolean Operator'

Error: Main method not found in class Calculate, please define the main method as: public static void main(String[] args)

Where you have written the code

public class Main {
    public static void main(String args[])
        Calculate obj = new Calculate(1,2,'+');

Here you have to run the class "Main" instead of the class you created at the start of the program. To do so pls go to Run Configuration and search for this class name"Main" which is having the main method inside this(public static void main(String args[])). And you will get your output.

Moment.js - How to convert date string into date?

If you are getting a JS based date String then first use the new Date(String) constructor and then pass the Date object to the moment method. Like:

var dateString = 'Thu Jul 15 2016 19:31:44 GMT+0200 (CEST)';
var dateObj = new Date(dateString);
var momentObj = moment(dateObj);
var momentString = momentObj.format('YYYY-MM-DD'); // 2016-07-15

In case dateString is 15-07-2016, then you should use the moment(date:String, format:String) method

var dateString = '07-15-2016';
var momentObj = moment(dateString, 'MM-DD-YYYY');
var momentString = momentObj.format('YYYY-MM-DD'); // 2016-07-15

How do I sort an observable collection?

What the heck, I'll throw in a quickly-cobbled-together answer as looks a bit like some other implementations here, but I'll add it anywho:

(barely tested, hopefully I'm not embarassing myself)

Let's state some goals first (my assumptions):

1) Must sort ObservableCollection<T> in place, to maintain notifications, etc.

2) Must not be horribly inefficient (i.e., something close to standard "good" sorting efficiency)

public static class Ext
    public static void Sort<T>(this ObservableCollection<T> src)
        where T : IComparable<T>
        // Some preliminary safety checks
        if(src == null) throw new ArgumentNullException("src");
        if(!src.Any()) return;

        // N for the select,
        // + ~ N log N, assuming "smart" sort implementation on the OrderBy
        // Total: N log N + N (est)
        var indexedPairs = src
            .Select((item,i) => Tuple.Create(i, item))
            .OrderBy(tup => tup.Item2);
        // N for another select
        var postIndexedPairs = indexedPairs
            .Select((item,i) => Tuple.Create(i, item.Item1, item.Item2));
        // N for a loop over every element
        var pairEnum = postIndexedPairs.GetEnumerator();
        for(int idx = 0; idx < src.Count; idx++, pairEnum.MoveNext())
            src.Insert(idx, pairEnum.Current.Item3);            
        // (very roughly) Estimated Complexity: 
        // N log N + N + N + N
        // == N log N + 3N

Regex to match 2 digits, optional decimal, two digits

To build on Lee's answer, you need to anchor the expression to satisfy the requirement of not having more than 2 numbers before the decimal.

If each number is a separate string, you can use the string anchors:


If each number is within a string, you can use the word anchors:


Why does an SSH remote command get fewer environment variables then when run manually?

How about sourcing the profile before running the command?

ssh user@host "source /etc/profile; /path/"

You might find it best to change that to ~/.bash_profile, ~/.bashrc, or whatever.

(As here (

create unique id with javascript

I think if you really want to have a unique ID then the best approach is to use a library like:
uuid or uniqueid

Note: Unique ID is not the same as Random ID

To use only date time milliseconds approach is wrong.
Nowadays computers are fast enough and able to run more than one iteration of a loop in a single millisecond.

npm install uuid

Importing the library:

If you are using ES modules

import { v4 as uuidv4 } from 'uuid';

And for CommonJS:

const { v4: uuidv4 } = require('uuid');



// This will output something like: 9b1deb4d-3b7d-4bad-9bdd-2b0d7b3dcb6d

What is the proper way to comment functions in Python?

Read about using docstrings in your Python code.

As per the Python docstring conventions:

The docstring for a function or method should summarize its behavior and document its arguments, return value(s), side effects, exceptions raised, and restrictions on when it can be called (all if applicable). Optional arguments should be indicated. It should be documented whether keyword arguments are part of the interface.

There will be no golden rule, but rather provide comments that mean something to the other developers on your team (if you have one) or even to yourself when you come back to it six months down the road.

Creating Roles in Identity MVC 5

the method i Use for creating roles is below, assigning them to users in code is also listed. the below code does be in "configuration.cs" in the migrations folder.

string [] roleNames = { "role1", "role2", "role3" };
var RoleManager = new RoleManager<IdentityRole>(new RoleStore<IdentityRole>(context));

                IdentityResult roleResult;
                foreach(var roleName in roleNames)
                        roleResult = RoleManager.Create(new IdentityRole(roleName));
                var UserManager = new UserManager<ApplicationUser>(new UserStore<ApplicationUser>(context));
                UserManager.AddToRole("user", "role1");
                UserManager.AddToRole("user", "role2");

HTML5 input type range show range value

an even better way would be to catch the input event on the input itself rather than on the whole form (performance wise) :

<input type="range" id="rangeInput" name="rangeInput" min="0" max="20" value="0"

<output id="amount" name="amount" for="rangeInput">0</output>

Here's a fiddle (with the id added as per Ryan's comment).

Int to byte array

If you came here from Google

Alternative answer to an older question refers to John Skeet's Library that has tools for letting you write primitive data types directly into a byte[] with an Index offset. Far better than BitConverter if you need performance.

Older thread discussing this issue here

John Skeet's Libraries are here

Just download the source and look at the MiscUtil.Conversion namespace. EndianBitConverter.cs handles everything for you.

Is there a way to get a collection of all the Models in your Rails app?

To avoid pre-load all Rails, you can do this:

Dir.glob("#{Rails.root}/app/models/**/*.rb").each {|f| require_dependency(f) }

require_dependency(f) is the same that Rails.application.eager_load! uses. This should avoid already required file errors.

Then you can use all kind of solutions to list AR models, like ActiveRecord::Base.descendants

How do I position a div relative to the mouse pointer using jQuery?

<script type="text/javascript" language="JavaScript">

  var cX = 0;
  var cY = 0;
  var rX = 0;
  var rY = 0;

  function UpdateCursorPosition(e) {
    cX = e.pageX;
    cY = e.pageY;

  function UpdateCursorPositionDocAll(e) {
    cX = event.clientX;
    cY = event.clientY;
  if (document.all) {
    document.onmousemove = UpdateCursorPositionDocAll;
  } else {
    document.onmousemove = UpdateCursorPosition;

  function AssignPosition(d) {
    if (self.pageYOffset) {
      rX = self.pageXOffset;
      rY = self.pageYOffset;
    } else if (document.documentElement && document.documentElement.scrollTop) {
      rX = document.documentElement.scrollLeft;
      rY = document.documentElement.scrollTop;
    } else if (document.body) {
      rX = document.body.scrollLeft;
      rY = document.body.scrollTop;
    if (document.all) {
      cX += rX;
      cY += rY;
    } = (cX + 10) + "px"; = (cY + 10) + "px";

  function HideContent(d) {
    if (d.length < 1) {
    document.getElementById(d).style.display = "none";

  function ShowContent(d) {
    if (d.length < 1) {
    var dd = document.getElementById(d);
    AssignPosition(dd); = "block";

  function ReverseContentDisplay(d) {
    if (d.length < 1) {
    var dd = document.getElementById(d);
    if ( == "none") { = "block";
    } else { = "none";

<a onmouseover="ShowContent('uniquename3'); return true;" onmouseout="HideContent('uniquename3'); return true;" href="javascript:ShowContent('uniquename3')">
[show on mouseover, hide on mouseout]
<div id="uniquename3" style="display:none;
border-style: solid;
background-color: white;
padding: 5px;">
  Content goes here.

fast way to copy formatting in excel

For me, you can't. But if that suits your needs, you could have speed and formatting by copying the whole range at once, instead of looping:

range("B2:B5002").Copy Destination:=Sheets("Output").Cells(startrow, 2)

And, by the way, you can build a custom range string, like Range("B2:B4, B6, B11:B18")

edit: if your source is "sparse", can't you just format the destination at once when the copy is finished ?

right click context menu for datagridview

  • Put a context menu on your form, name it, set captions etc. using the built-in editor
  • Link it to your grid using the grid property ContextMenuStrip
  • For your grid, create an event to handle CellContextMenuStripNeeded
  • The Event Args e has useful properties e.ColumnIndex, e.RowIndex.

I believe that e.RowIndex is what you are asking for.

Suggestion: when user causes your event CellContextMenuStripNeeded to fire, use e.RowIndex to get data from your grid, such as the ID. Store the ID as the menu event's tag item.

Now, when user actually clicks your menu item, use the Sender property to fetch the tag. Use the tag, containing your ID, to perform the action you need.

Using different Web.config in development and production environment

I'd like to know, too. This helps isolate the problem for me

<connectionStrings configSource="connectionStrings.config"/>

I then keep a connectionStrings.config as well as a "{host} connectionStrings.config". It's still a problem, but if you do this for sections that differ in the two environments, you can deploy and version the same web.config.

(And I don't use VS, btw.)

Check if a row exists, otherwise insert

I assume a single row for each flight? If so:


I assume what I said, as your way of doing things can overbook a flight, as it will insert a new row when there are 10 tickets max and you are booking 20.

How to convert datetime to integer in python

This in an example that can be used for example to feed a database key, I sometimes use instead of using AUTOINCREMENT options.

import datetime 

dt =
seq = int(dt.strftime("%Y%m%d%H%M%S"))

Polygon Drawing and Getting Coordinates with Google Map API v3

It's cleaner/safer to use the getters provided by google instead of accessing the properties like some did

google.maps.event.addListener(drawingManager, 'overlaycomplete', function(polygon) {
    var coordinatesArray = polygon.overlay.getPath().getArray();

Swing JLabel text change on the running application

import java.awt.*;
import javax.swing.*;
import javax.swing.border.*;
import java.awt.event.*;
public class Test extends JFrame implements ActionListener
    private JLabel label;
    private JTextField field;
    public Test()
        super("The title");
        setPreferredSize(new Dimension(400, 90));
        ((JPanel) getContentPane()).setBorder(new EmptyBorder(13, 13, 13, 13) );
        setLayout(new FlowLayout());
        JButton btn = new JButton("Change");
        label = new JLabel("flag");
        field = new JTextField(5);
    public void actionPerformed(ActionEvent e)
    public static void main(String[] args)
        new Test();

#1130 - Host ‘localhost’ is not allowed to connect to this MySQL server

Use the IP instead:

DROP USER 'root'@''; GRANT ALL PRIVILEGES ON . TO 'root'@'%';

For more possibilities, see this link.

To create the root user, seeing as MySQL is local & all, execute the following from the command line (Start > Run > "cmd" without quotes):

mysqladmin -u root password 'mynewpassword'

Documentation, and Lost root access in MySQL.

When to use Hadoop, HBase, Hive and Pig?


HDFS stands for Hadoop Distributed File System which uses Computational processing model Map-Reduce.


HBase is Key-Value storage, good for reading and writing in near real time.


Hive is used for data extraction from the HDFS using SQL-like syntax. Hive use HQL language.


Pig is a data flow language for creating ETL. It's an scripting language.

java.lang.ClassNotFoundException: HttpServletRequest

The same error i got

Caused by: org.apache.catalina.LifecycleException: A child container failed during start

I deleted the project from eclipse work space , deleted .settings folder of project and re imported to the eclipse. Did the trick for me.

Converting HTML string into DOM elements?

Here is a little code that is useful.

var uiHelper = function () {

var htmls = {};

var getHTML = function (url) {
                /// <summary>Returns HTML in a string format</summary>
                /// <param name="url" type="string">The url to the file with the HTML</param>

    if (!htmls[url])
    var xmlhttp = new XMLHttpRequest();"GET", url, false);
    htmls[url] = xmlhttp.responseText;
     return htmls[url];

        return {
            getHTML: getHTML

--Convert the HTML string into a DOM Element

String.prototype.toDomElement = function () {

        var wrapper = document.createElement('div');
        wrapper.innerHTML = this;
        var df= document.createDocumentFragment();
        return df.addChilds(wrapper.children);

--prototype helper

HTMLElement.prototype.addChilds = function (newChilds) {
        /// <summary>Add an array of child elements</summary>
        /// <param name="newChilds" type="Array">Array of HTMLElements to add to this HTMLElement</param>
        /// <returns type="this" />
        for (var i = 0; i < newChilds.length; i += 1) { this.appendChild(newChilds[i]); };
        return this;


 thatHTML = uiHelper.getHTML('/Scripts/elevation/ui/add/html/add.txt').toDomElement();

Can I set subject/content of email using mailto:?

If you want to add html content to your email, url encode your html code for the message body and include it in your mailto link code, but trouble is you can't set the type of the email from this link from plaintext to html, the client using the link needs their mail client to send html emails by default. In case you want to test here is the code for a simple mailto link, with an image wrapped in a link (angular style urls added for visibility):

<a href="mailto:?body=%3Ca%20href%3D%22{{ scope.url }}%22%3E%3Cimg%20src%3D%22{{ scope.url }}%22%20width%3D%22300%22%20%2F%3E%3C%2Fa%3E">

The html tags are url encoded.

How to put individual tags for a scatter plot

Perhaps use plt.annotate:

import numpy as np
import matplotlib.pyplot as plt

N = 10
data = np.random.random((N, 4))
labels = ['point{0}'.format(i) for i in range(N)]

plt.subplots_adjust(bottom = 0.1)
    data[:, 0], data[:, 1], marker='o', c=data[:, 2], s=data[:, 3] * 1500,

for label, x, y in zip(labels, data[:, 0], data[:, 1]):
        xy=(x, y), xytext=(-20, 20),
        textcoords='offset points', ha='right', va='bottom',
        bbox=dict(boxstyle='round,pad=0.5', fc='yellow', alpha=0.5),
        arrowprops=dict(arrowstyle = '->', connectionstyle='arc3,rad=0'))

enter image description here

Better way to Format Currency Input editText?

Kotlin version:

    var current = ""

    editText.addTextChangedListener(object: TextWatcher {
        override fun afterTextChanged(s: Editable?) {}
        override fun beforeTextChanged(s: CharSequence?, start: Int, count: Int, after: Int) {}

        override fun onTextChanged(s: CharSequence?, start: Int, before: Int, count: Int) {
            val stringText = s.toString()

            if(stringText != current) {

                val locale: Locale = Locale.UK
                val currency = Currency.getInstance(locale)
                val cleanString = stringText.replace("[${currency.symbol},.]".toRegex(), "")
                val parsed = cleanString.toDouble()
                val formatted = NumberFormat.getCurrencyInstance(locale).format(parsed / 100)

                current = formatted

Sorting string array in C#

If you have problems with numbers (say 1, 2, 10, 12 which will be sorted 1, 10, 12, 2) you can use LINQ:

var arr = arr.OrderBy(x=>x).ToArray();

Doctrine - How to print out the real sql, not just the prepared statement?

Maybe it can be useful for someone:

// Printing the SQL with real values
$vals = $query->getFlattenedParams();
foreach(explode('?', $query->getSqlQuery()) as $i => $part) {
    $sql = (isset($sql) ? $sql : null) . $part;
    if (isset($vals[$i])) $sql .= $vals[$i];

echo $sql;

How can I catch a ctrl-c event?

signal isn't the most reliable way as it differs in implementations. I would recommend using sigaction. Tom's code would now look like this :

#include <signal.h>
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>

void my_handler(int s){
           printf("Caught signal %d\n",s);


int main(int argc,char** argv)

   struct sigaction sigIntHandler;

   sigIntHandler.sa_handler = my_handler;
   sigIntHandler.sa_flags = 0;

   sigaction(SIGINT, &sigIntHandler, NULL);


   return 0;    

JQuery Parsing JSON array

var dataArray = [];
var obj = jQuery.parseJSON(yourInput);

$.each(obj, function (index, value) {
    dataArray.push([value["yourID"].toString(), value["yourValue"] ]);

this helps me a lot :-)

How to kill all processes matching a name?

use pgrep

kill -9 $(pgrep amarok)

How to write header row with csv.DictWriter?

A few options:

(1) Laboriously make an identity-mapping (i.e. do-nothing) dict out of your fieldnames so that csv.DictWriter can convert it back to a list and pass it to a csv.writer instance.

(2) The documentation mentions "the underlying writer instance" ... so just use it (example at the end).


(3) Avoid the csv.Dictwriter overhead and do it yourself with csv.writer

Writing data:

w.writerow([d[k] for k in fieldnames])


w.writerow([d.get(k, restval) for k in fieldnames])

Instead of the extrasaction "functionality", I'd prefer to code it myself; that way you can report ALL "extras" with the keys and values, not just the first extra key. What is a real nuisance with DictWriter is that if you've verified the keys yourself as each dict was being built, you need to remember to use extrasaction='ignore' otherwise it's going to SLOWLY (fieldnames is a list) repeat the check:

wrong_fields = [k for k in rowdict if k not in self.fieldnames]


>>> f = open('csvtest.csv', 'wb')
>>> import csv
>>> fns = 'foo bar zot'.split()
>>> dw = csv.DictWriter(f, fns, restval='Huh?')
# dw.writefieldnames(fns) -- no such animal
>>> dw.writerow(fns) # no such luck, it can't imagine what to do with a list
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "C:\python26\lib\", line 144, in writerow
    return self.writer.writerow(self._dict_to_list(rowdict))
  File "C:\python26\lib\", line 141, in _dict_to_list
    return [rowdict.get(key, self.restval) for key in self.fieldnames]
AttributeError: 'list' object has no attribute 'get'
>>> dir(dw)
['__doc__', '__init__', '__module__', '_dict_to_list', 'extrasaction', 'fieldnam
es', 'restval', 'writer', 'writerow', 'writerows']
# eureka
>>> dw.writer.writerow(dw.fieldnames)
>>> dw.writerow({'foo':'oof'})
>>> f.close()
>>> open('csvtest.csv', 'rb').read()

Simple way to compare 2 ArrayLists

As far as I understand it correctly, I think it's easiest to work with 4 lists: - Your sourceList - Your destinationList - A removedItemsList - A newlyAddedItemsList

Unable to set data attribute using jQuery Data() API

Had the same problem. Since you can still get data using the .data() method, you only have to figure out a way to write to the elements. This is the helper method I use. Like most people have said, you will have to use .attr. I have it replacing any _ with - as I know it does that. I'm not aware of any other characters it replaces...however I have not researched that.

function ExtendElementData(element, object){
    //element is what you want to set data on
    //object is a hash/js-object
    var keys = Object.keys(object);
    for (var i = 0; i < keys.length; i++){
        var key = keys[i];
        $(element).attr('data-'+key.replace("_", "-"), object[key]);

EDIT: 5/1/2017

I found there were still instances where you could not get the correct data using built in methods so what I use now is as follows:

function setDomData(element, object){
    //object is a hash

    var keys = Object.keys(object);
    for (var i = 0; i < keys.length; i++){
        var key = keys[i];
        $(element).attr('data-'+key.replace("_", "-"), object[key]);

function getDomData(element, key){
    var domObject = $(element).get(0);
    var attKeys = Object.keys(domObject.attributes);

    var values = null;
    if (key != null){
        values = $(element).attr('data-' + key);
    } else {
        values = {};

        var keys = [];
        for (var i = 0; i < attKeys.length; i++) {

        for (var i = 0; i < keys.length; i++){
                values[keys[i]] = $(element).attr(keys[i]);
    return values;

How to get single value from this multi-dimensional PHP array

I think you want this:

foreach ($myarray as $key => $value) {
    echo "$key = $value\n";

Remove a fixed prefix/suffix from a string in Bash

Using @Adrian Frühwirth answer:

function strip {
    local STRING=${1#$"$2"}
    echo ${STRING%$"$2"}

use it like this

HELLO=$(strip "$HELLO" ":")
echo $HELLO # hello

How can I return camelCase JSON serialized by JSON.NET from ASP.NET MVC controller methods?

or, simply put:

    new JsonSerializerSettings 
        ContractResolver = new CamelCasePropertyNamesContractResolver() 

For instance:

return new ContentResult
    ContentType = "application/json",
    Content = JsonConvert.SerializeObject(new { content = result, rows = dto }, new JsonSerializerSettings { ContractResolver = new CamelCasePropertyNamesContractResolver() }),
    ContentEncoding = Encoding.UTF8

Change URL without refresh the page


Based on Manipulating the browser history, passing the empty string as second parameter of pushState method (aka title) should be safe against future changes to the method, so it's better to use pushState like this:

history.pushState(null, '', '/en/step2');    

You can read more about that in mentioned article

Original Answer

Use history.pushState like this:

history.pushState(null, null, '/en/step2');

Update 2 to answer Idan Dagan's comment:

Why not using history.replaceState()?

From MDN

history.replaceState() operates exactly like history.pushState() except that replaceState() modifies the current history entry instead of creating a new one

That means if you use replaceState, yes the url will be changed but user can not use Browser's Back button to back to prev. state(s) anymore (because replaceState doesn't add new entry to history) and it's not recommended and provide bad UX.

Update 3 to add window.onpopstate

So, as this answer got your attention, here is additional info about manipulating the browser history, after using pushState, you can detect the back/forward button navigation by using window.onpopstate like this:

window.onpopstate = function(e) {
    // ... 

As the first argument of pushState is an object, if you passed an object instead of null, you can access that object in onpopstate which is very handy, here is how:

window.onpopstate = function(e) {
    if(e.state) {

Update 4 to add Reading the current state:

When your page loads, it might have a non-null state object, you can read the state of the current history entry without waiting for a popstate event using the history.state property like this:


Bonus: Use following to check history.pushState support:

if (history.pushState) {
  // \o/

Determine the size of an InputStream

For InputStream

For Optional < MultipartFile >


error: Error parsing XML: not well-formed (invalid token) ...?

Verify that you don't have any spaces or tabs before

<?xml version="1.0" encoding="utf-8"?>

also refresh and clean your project in eclipse.

I get this error every now and then and the above suggestions fix the issue 99% of the time

How to run python script in webpage

In order for your code to show, you need several things:

Firstly, there needs to be a server that handles HTTP requests. At the moment you are just opening a file with Firefox on your local hard drive. A server like Apache or something similar is required.

Secondly, presuming that you now have a server that serves the files, you will also need something that interprets the code as Python code for the server. For Python users the go to solution is nowadays mod_wsgi. But for simpler cases you could stick with CGI (more info here), but if you want to produce web pages easily, you should go with a existing Python web framework like Django.

Setting this up can be quite the hassle, so be prepared.

Use ssh from Windows command prompt

Cygwin can give you this functionality.

For..In loops in JavaScript - key value pairs

In the last few year since this question was made, Javascript has added a few new features. One of them is the Object.Entries method.

Copied directly from MDN is the follow code snippet

const object1 = {
  a: 'somestring',
  b: 42

for (let [key, value] of Object.entries(object1)) {
  console.log(`${key}: ${value}`);

Passing Multiple route params in Angular2

OK realized a mistake .. it has to be /:id/:id2

Anyway didn't find this in any tutorial or other StackOverflow question.

@RouteConfig([{path: '/component/:id/:id2',name: 'MyCompB', component:MyCompB}])
export class MyCompA {
        this._router.navigate( ['MyCompB', {id: "someId", id2: "another ID"}]);

Search for value in DataGridView in a column

Why you are using row.Cells[row.Index]. You need to specify index of column you want to search (Problem #2). For example, you need to change row.Cells[row.Index] to row.Cells[2] where 2 is index of your column:

private void btnSearch_Click(object sender, EventArgs e)
    string searchValue = textBox1.Text;

    dgvProjects.SelectionMode = DataGridViewSelectionMode.FullRowSelect;
        foreach (DataGridViewRow row in dgvProjects.Rows)
            if (row.Cells[2].Value.ToString().Equals(searchValue))
                row.Selected = true;
    catch (Exception exc)

How to get all of the IDs with jQuery?

You can get the ids of specifict tags and send it to a annother element. For exemple:

$("input").map(function() {
    $( "textarea" ).append("\n");

It will get all input ids and send it to textarea.

LINQ Contains Case Insensitive

IndexOf works best in this case

return this
   .Where(fi => fi.DESCRIPTION.IndexOf(description, StringComparison.OrdinalIgnoreCase)>=0);

Get the current script file name

__FILE__ use examples based on localhost server results:

echo __FILE__;
// C:\LocalServer\www\templates\page.php

echo strrchr( __FILE__ , '\\' );
// \page.php

echo substr( strrchr( __FILE__ , '\\' ), 1);
// page.php

echo basename(__FILE__, '.php');
// page

How do I set the default page of my application in IIS7?

If you want to do something like,User enter url "" & default page is displayed then I guess you have to set the default/home/welcome page attribute in IIS. But if user just enters "" and you still want to forward to your url, then you have write a line of code in the default page to forward to your desired url. This default page should be in root directory of your application, so will load which will redirect the user to your desired url

SQLite error 'attempt to write a readonly database' during insert?

I used:

echo exec('whoami');

to find out who is running the script (say username), and then gave the user permissions to the entire application directory, like:

sudo chown -R :username /var/www/html/myapp

Hope this helps someone out there.

jQuery UI Tabs - How to Get Currently Selected Tab Index

UPDATE [Sun 08/26/2012] This answer has become so popular that I decided to make it into a full-fledged blog/tutorial
Please visit My Blog Here to see the latest in easy access information to working with tabs in jQueryUI
Also included (in the blog too) is a jsFiddle

¡¡¡ Update! Please note: In newer versions of jQueryUI (1.9+), ui-tabs-selected has been replaced with ui-tabs-active. !!!

I know this thread is old, but something I didn't see mentioned was how to get the "selected tab" (Currently dropped down panel) from somewhere other than the "tab events". I do have a simply way ...

var curTab = $('.ui-tabs-panel:not(.ui-tabs-hide)');

And to easily get the index, of course there is the way listed on the site ...

var $tabs = $('#example').tabs();
var selected = $tabs.tabs('option', 'selected'); // => 0

However, you could use my first method to get the index and anything you want about that panel pretty easy ...

var curTab = $('.ui-tabs-panel:not(.ui-tabs-hide)'),
    curTabIndex = curTab.index(),
    curTabID = curTab.prop("id"),
    curTabCls = curTab.attr("class");
        //  etc ....

PS. If you use an iframe variable then .find('.ui-tabs-panel:not(.ui-tabs-hide)'), you will find it easy to do this for selected tabs in frames as well. Remember, jQuery already did all the hard work, no need to reinvent the wheel!

Just to expand (updated)

Question was brought up to me, "What if there are more than one tabs areas on the view?" Again, just think simple, use my same setup but use an ID to identify which tabs you want to get hold of.

For example, if you have:


And you want the current panel of the second tab set:

var curTabPanel = $('#example-2 .ui-tabs-panel:not(.ui-tabs-hide)');

And if you want the ACTUAL tab and not the panel (really easy, which is why I ddn't mention it before but I suppose I will now, just to be thorough)

// for page with only one set of tabs
var curTab = $('.ui-tabs-selected'); // '.ui-tabs-active' in jQuery 1.9+

// for page with multiple sets of tabs
var curTab2 = $('#example-2 .ui-tabs-selected'); // '.ui-tabs-active' in jQuery 1.9+

Again, remember, jQuery did all the hard work, don't think so hard.

Checking if a number is an Integer in Java

Quick and dirty...

if (x == (int)x)

edit: This is assuming x is already in some other numeric form. If you're dealing with strings, look into Integer.parseInt.

How do I add an existing directory tree to a project in Visual Studio?

As far as I can tell, the only way to do this in VS2010 is akin to the drag and drop method. Right click the solution to which you want to add a project. The application menu will have an add ... item. Opening that, you find that one of the options is to add an existing project to the solution.

In the dialog box that opens, navigate to the folder containing the project file for the solution and select it. VS will, as part of importing that project file, also import the entire directory and, I assume any subordinate directories which are part of that project.

As this does require an existing project file, it won't be impossible to import a directory tree until that tree has been converted to a project.

converting date time to 24 hour format

You should take a look at Java date formatting, in particular SimpleDateFormat. There's some examples here: - but you can also find a lot more with a quick google.

How to set a header for a HTTP GET request, and trigger file download?

There are two ways to download a file where the HTTP request requires that a header be set.

The credit for the first goes to @guest271314, and credit for the second goes to @dandavis.

The first method is to use the HTML5 File API to create a temporary local file, and the second is to use base64 encoding in conjunction with a data URI.

The solution I used in my project uses the base64 encoding approach for small files, or when the File API is not available, otherwise using the the File API approach.


        var id = 123;

        var req = ic.ajax.raw({
            type: 'GET',
            url: '/api/dowloads/'+id,
            beforeSend: function (request) {
                request.setRequestHeader('token', 'token for '+id);
            processData: false

        var maxSizeForBase64 = 1048576; //1024 * 1024

            function resolve(result) {
                var str = result.response;

                var anchor = $('.vcard-hyperlink');
                var windowUrl = window.URL || window.webkitURL;
                if (str.length > maxSizeForBase64 && typeof windowUrl.createObjectURL === 'function') {
                    var blob = new Blob([result.response], { type: 'text/bin' });
                    var url = windowUrl.createObjectURL(blob);
                    anchor.prop('href', url);
                    anchor.prop('download', id+'.bin');
                else {
                    //use base64 encoding when less than set limit or file API is not available
                        href: 'data:text/plain;base64,'+FormatUtils.utf8toBase64(result.response),
                        download: id+'.bin',

            function reject(err) {

Note that I'm not using a raw XMLHttpRequest, and instead using ic-ajax, and should be quite similar to a jQuery.ajax solution.

Note also that you should substitute text/bin and .bin with whatever corresponds to the file type being downloaded.

The implementation of FormatUtils.utf8toBase64 can be found here

com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure

I got the communications failure error when using a java.sql.PreparedStatement with a specific statement.

This was running against MySQL 5.6, Tomcat 7.0.29 and JDK 1.7.0_67 on a Windows 7 x64 machine.

The cause turned out to be setting an integer to a string parameter and a string to an integer parameter then trying to perform executeQuery on the prepared statement. After I corrected the order of parameter setting the statement performed correctly.

This had nothing to do with network issues as the wording of the error message suggested.

Difference between single and double quotes in Bash

Since this is the de facto answer when dealing with quotes in bash, I'll add upon one more point missed in the answers above, when dealing with the arithmetic operators in the shell.

The bash shell supports two ways do arithmetic operation, one defined by the built-in let command and the $((..)) operator. The former evaluates an arithmetic expression while the latter is more of a compound statement.

It is important to understand that the arithmetic expression used with let undergoes word-splitting, pathname expansion just like any other shell commands. So proper quoting and escaping needs to be done.

See this example when using let

let 'foo = 2 + 1'
echo $foo

Using single quotes here is absolutely fine here, as there is no need for variable expansions here, consider a case of

let 'foo = $bar + 1'

would fail miserably, as the $bar under single quotes would not expand and needs to be double-quoted as

let 'foo = '"$bar"' + 1'

This should be one of the reasons, the $((..)) should always be considered over using let. Because inside it, the contents aren't subject to word-splitting. The previous example using let can be simply written as

(( bar=1, foo = bar + 1 ))

Always remember to use $((..)) without single quotes

Though the $((..)) can be used with double-quotes, there is no purpose to it as the result of it cannot contain a content that would need the double-quote. Just ensure it is not single quoted.

printf '%d\n' '$((1+1))'
-bash: printf: $((1+1)): invalid number
printf '%d\n' $((1+1))
printf '%d\n' "$((1+1))"

May be in some special cases of using the $((..)) operator inside a single quoted string, you need to interpolate quotes in a way that the operator either is left unquoted or under double quotes. E.g. consider a case, when you are tying to use the operator inside a curl statement to pass a counter every time a request is made, do

curl --data-binary '{"requestCounter":'"$((reqcnt++))"'}'

Notice the use of nested double-quotes inside, without which the literal string $((reqcnt++)) is passed to requestCounter field.

Why does the Visual Studio editor show dots in blank spaces?

In Visual Studio vesrion 1.34.0 View -> Toggle Render Whitespace

How do I get the current absolute URL in Ruby on Rails?

if you want to be specific, meaning, you know the path you need:

link_to current_path(@resource, :only_path => false), current_path(@resource)

Error : Program type already present:$Behavior

The solution for this is that remove this following dependency:

implementation ''

put general dependencies as:

dependencies {
    implementation fileTree(include: ['*.jar'], dir: 'libs')
    //noinspection GradleCompatible
    implementation ''
    implementation ''
    implementation ''    
    implementation ''
    testImplementation 'junit:junit:4.12'
    androidTestImplementation ''
    androidTestImplementation ''
    implementation ''

jQuery - Detecting if a file has been selected in the file input

You should be able to attach an event handler to the onchange event of the input and have that call a function to set the text in your span.

<script type="text/javascript">
  $(function() {
     $("input:file").change(function (){
       var fileName = $(this).val();

You may want to add IDs to your input and span so you can select based on those to be specific to the elements you are concerned with and not other file inputs or spans in the DOM.

NSURLErrorDomain error codes description

I received the error Domain=NSURLErrorDomain Code=-1011 when using Parse, and providing the wrong clientKey. As soon as I corrected that, it began working.

How do I provide a username and password when running "git clone [email protected]"?

Follow this arguments to replace with ur special cases if they are creating an issue:

! # $ & ' ( ) * + , / : ; = ? @ [ ]

%21 %23 %24 %26 %27 %28 %29 %2A %2B %2C %2F %3A %3B %3D %3F %40 %5B %5D

So for example-

actual URL: https://usern@me:p@ssword@git/reponame.git

Solution URL to use: https://usern%40me:p%40ssword@git/reponame.git

How can I check what version/edition of Visual Studio is installed programmatically?

Put this code somewhere in your C++ project:

#ifdef _DEBUG
TCHAR version[50];
sprintf(&version[0], "Version = %d", _MSC_VER);
MessageBox(NULL, (LPCTSTR)szMsg, "Visual Studio", MB_OK | MB_ICONINFORMATION);

Note that _MSC_VER symbol is Microsoft specific. Here you can find a list of Visual Studio versions with the value for _MSC_VER for each version.

How to get the first column of a pandas DataFrame as a Series?

From v0.11+, ... use df.iloc.

In [7]: df.iloc[:,0]
0    1
1    2
2    3
3    4
Name: x, dtype: int64

multiple prints on the same line in Python

Found this Quora post, with this example which worked for me (python 3), which was closer to what I needed it for (i.e. erasing the whole previous line).

The example they provide:

def clock():
   while True:
       print("%H:%M:%S"), end="\r")

For printing the on the same line, as others have suggested, just use end=""

Rails: Address already in use - bind(2) (Errno::EADDRINUSE)

To kill the puma process first run

    lsof -wni tcp:3000 

to show what is using port 3000. Then use the PID that comes with the result to run the kill process.

For example after running lsof -wni tcp:3000 you might get something like

    ruby    3366 dummy    8u  IPv4  16901      0t0  TCP (LISTEN)

Now run the following to kill the process. (where 3366 is the PID)

kill -9 3366

Should resolve the issue

When must we use NVARCHAR/NCHAR instead of VARCHAR/CHAR in SQL Server?

Josh says: "....Something to keep in mind when you are using Unicode although you can store different languages in a single column you can only sort using a single collation. There are some languages that use latin characters but do not sort like other latin languages. Accents is a good example of this, I can't remeber the example but there was a eastern european language whose Y didn't sort like the English Y. Then there is the spanish ch which spanish users expet to be sorted after h."

I'm a native Spanish Speaker and "ch" is not a letter but two "c" and "h" and the Spanish alphabet is like: abcdefghijklmn ñ opqrstuvwxyz We don't expect "ch" after "h" but "i" The alphabet is the same as in English except for the ñ or in HTML "&ntilde ;"


null terminating a string

Be very careful: NULL is a macro used mainly for pointers. The standard way of terminating a string is:

char *buffer;
buffer[end_position] = '\0';

This (below) works also but it is not a big difference between assigning an integer value to a int/short/long array and assigning a character value. This is why the first version is preferred and personally I like it better.

buffer[end_position] = 0; 

Vertically align text within input field of fixed-height without display: table or padding?

You should remove your title text and use the input placeholder for your label's title. Some visual and CSS work after that and your form will be looking tight and user friendly. I'm aware of the disadvantages but this will completely relieve the alignment wrestling.

"static const" vs "#define" vs "enum"

Another drawback of const in C is that you can't use the value in initializing another const.

static int const NUMBER_OF_FINGERS_PER_HAND = 5;
static int const NUMBER_OF_HANDS = 2;

// initializer element is not constant, this does not work.
                                     * NUMBER_OF_HANDS;

Even this does not work with a const since the compiler does not see it as a constant:

static uint8_t const ARRAY_SIZE = 16;
static int8_t const lookup_table[ARRAY_SIZE] = {
    1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16}; // ARRAY_SIZE not a constant!

I'd be happy to use typed const in these cases, otherwise...

How can I enable or disable the GPS programmatically on Android?


Intent intent=new Intent("android.location.GPS_ENABLED_CHANGE");
intent.putExtra("enabled", true);


Intent intent = new Intent("android.location.GPS_ENABLED_CHANGE");
intent.putExtra("enabled", false);

call a function in success of datatable ajax call

You can use this:

"drawCallback": function(settings) {
   //do whatever  

How to JSON decode array elements in JavaScript?

I decode JSON this way:

eval( 'var from_json_object = ' + my_json_str + ';' );

How to align linearlayout to vertical center?

Use android:weightSum property to the parent LinearLayout and give value 3. Then in the children LinearLayout use android:layout_weight 2 and 1 respectively. Then in the First Chil LinearLayout use android:layout_gravity="center_vertical". As shown in the following code



Why do I get "warning longer object length is not a multiple of shorter object length"?

I had a similar issue and using %in% operator instead of the == (equality) operator was the solution:

# %in%

Hope it helps.

Good Java graph algorithm library?

It's also good to be convinced that a Graph can be represented as simply as :

class Node {
   int value;
   List<Node> adj;

and implement most the algorithms you find interesting by yourself. If you fall on this question in the middle of some practice/learning session on graphs, that's the best lib to consider. ;)

You can also prefer adjacency matrix for most common algorithms :

class SparseGraph {
  int[] nodeValues;
  List<Integer>[] edges;     

or a matrix for some operations :

class DenseGraph {
  int[] nodeValues;
  int[][] edges;     

How to test android apps in a real device with Android Studio?

I have a Nexus 4 and own a Thinkpad L430 Windows 8.1

My errors: "Waiting for device. USB device not found"

I went to: Device Manager > View > Drop to "Acer Device" > Right click on Acer Composite ADB Interface > Update it

Afterward, Reboot/Restart your computer. Once it turned on Plug Your USB Device onto the computer.

Go to: Setting > Enable "Developer options" > Check the "USB debugging" option > Check "Allow mock locations" > Check "Verify apps over USB".

Swipe down from the drop down menu of your phone where it Shows the USB Connection Icon. Tap on USB Computer Connection > Select the Check box "Camera (PTP)"

Run your Android Studio App and it should work

Can I change the scroll speed using css or jQuery?

Just use this js file. (I mentioned 2 examples with different js files. hope the second one is what you need) You can simply change the scroll amount, speed etc by changing the parameters.

Here's a Demo

You can also try this. Here's a demo

Cannot read property 'length' of null (javascript)

I tried this:

if(capital !== null){ 
//Capital has something 

Wpf control size to content?

I had a problem like this whereby I had specified the width of my Window, but had the height set to Auto. The child DockPanel had it's VerticalAlignment set to Top and the Window had it's VerticalContentAlignment set to Top, yet the Window would still be much taller than the contents.

Using Snoop, I discovered that the ContentPresenter within the Window (part of the Window, not something I had put there) has it's VerticalAlignment set to Stretch and can't be changed without retemplating the entire Window!

After a lot of frustration, I discovered the SizeToContent property - you can use this to specify whether you want the Window to size vertically, horizontally or both, according to the size of the contents - everything is sizing nicely now, I just can't believe it took me so long to find that property!

Get installed applications in a system

I agree that enumerating through the registry key is the best way.

Note, however, that the key given, @"SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall", will list all applications in a 32-bit Windows installation, and 64-bit applications in a Windows 64-bit installation.

In order to also see 32-bit applications installed on a Windows 64-bit installation, you would also need to enumeration the key @"SOFTWARE\WOW6432Node\Microsoft\Windows\CurrentVersion\Uninstall".

How to declare global variables in Android?

You could create a class that extends Application class and then declare your variable as a field of that class and providing getter method for it.

public class MyApplication extends Application {
    private String str = "My String";

    synchronized public String getMyString {
        return str;

And then to access that variable in your Activity, use this:

MyApplication application = (MyApplication) getApplication();
String myVar = application.getMyString();

IntelliJ does not show project folders

Check out answer at

Can't see project folders in IntelliJ IDEA

It might be because the project didn't have any modules defined. Try adding existing source code by hitting File > New > Module from Existing Sources and select the parent directory of the project for source codeenter image description here

Hook up Raspberry Pi via Ethernet to laptop without router?

No router + no screen + regular Ethernet cable + RPI 2 + Raspbian Lite 2018-11-13 + Ubuntu 18.10

First we must enable the SSH server on the Pi, which is disabled by default for security.

If you already have a shell on the Pi through a non-SSH method such as screen + keyboard or UART (see below), just run:

sudo systemctl enable ssh
sudo service sshd start

as explained at: This persists across boots.

Otherwise, insert he SD card on your host, and create a magic empty file named ssh file in the boot/ partition.

On Ubuntu hosts, it gets mounted automatically and you can do just:

sudo touch /media/$USER/boot/ssh

which you can confirm with:


which contains:

mmcblk0     179:0    0  14.4G  0 disk
+-mmcblk0p1 179:1    0  43.9M  0 part /media/ciro/boot
+-mmcblk0p2 179:2    0  14.4G  0 part /media/ciro/rootfs

If you don't enable the SSHD daemon on the Pi then SSH connection will fail with:

ssh: connect to host port 22: Connection refused

when we try it later on.

After enabling the SSH server

Next, boot the Pi, and link an Ethernet cable from your laptop directly to the Pi:

enter image description here

On Ubuntu 17.04 to work around this bug as mentioned on this answer you first need:

sudo apt-get install dnsmasq-base

On the host, open the network manager:


And go:

  1. + sign (Add a new connection)
  2. Ethernet
  3. Create
  4. IPv4 Settings
  5. Method: Shared to other computers
  6. Set a good name for it
  7. Save

enter image description here

Find the IP of the Pi on host:

cat /var/lib/misc/dnsmasq.leases

outputs something like:

1532204957 b8:27:eb:0c:1f:69 raspberrypi 01:b8:27:eb:0c:1f:69 is the IP, then as usual:

ssh [email protected]

I also have the following in my .bashrc:

piip() ( cat /var/lib/misc/dnsmasq.leases | cut -d ' ' -f 3; )
pissh() ( sshpass -p raspberry ssh "pi@$(piip)"; )

From inside the Pi, notice that it can access the internet normally through your host's other interfaces:


For example on my laptop, the Pi takes up the Ethernet, but the host is also connected to the internet through WiFi.

The crossover cable is not required if the host network card supports Auto MDI-X. This is the case for most recent hardware, including for example the 2012 Lenovo T430 I tested with, which has an "Intel® 82579LM Gigabit Network Connection" which documents support for Auto MDI-X.

Now you can also:

UART serial USB converter

This is an alternative to SSH if you just want to get a shell on the Pi:

This does not use SSH or networking itself, but rather the older, simpler, more direct, more reliable, lower bandwidth, lower distance serial interface. The Pi won't have access to the Internet with this method.

Desktop computers still have a serial port which you can connect directly wire to wire with the Pi, but these are hidden in most laptops, and so we need to buy a cheap USB adapter. Here I've used: See also:

First plug the SD card on the host, and edit the config.txt file present in the first partition to add:


as explained at:

This first partition contains the bootloader, its configuration files and the (Linux / your) kernel, config.txt being one of them. The second partition contains the actual Linux root filesystem.

Now connect your computer to the Pi as:

enter image description here

You only need to attach 3 cables:

  • Ground to Ground
  • Tx on Pi to Rx on the USB to serial port
  • Rx on Pi to Tx on tye USB to serial port

This is also documented at:

Be careful not to link the Ground to the 5V, I've already burned 2 UART to USB chips and a RPI UART by doing that!

You don't need to connect the 5V to the 5V at all. I think you can power your Pi like that, but I've read that this is a bad idea, just use the usual USB power source.

Finally, plug the USB side of the connector to your host computer, and get a shell with:

sudo apt install screen
sudo usermod -a -G dialout $USER
screen /dev/ttyUSB0 115200

Exit with Ctrl-A \.

Here is a video by Adafruit showing it:

See also

Similar question on RPI SE:

moving committed (but not pushed) changes to a new branch after pull

Here is a much simpler way:

  1. Create a new branch

  2. On your new branch do a git merge master- this will merge your committed (not pushed) changes to your new branch

  3. Delete you local master branch git branch -D master Use -D instead of -d because you want to force delete the branch.

  4. Just do a git fetch on your master branch and do a git pull on your master branch to ensure you have your teams latest code.

Get elements by attribute when querySelectorAll is not available without using libraries?

I played a bit around and ended up with this crude solution:

function getElementsByAttribute(attribute, context) {
  var nodeList = (context || document).getElementsByTagName('*');
  var nodeArray = [];
  var iterator = 0;
  var node = null;

  while (node = nodeList[iterator++]) {
    if (node.hasAttribute(attribute)) nodeArray.push(node);

  return nodeArray;

The usage is quite simple, and works even in IE8:

// or with parentNode
getElementsByAttribute('data-foo', document);

But I recommend to use querySelector / All for this (and to support older browsers use a polyfill):


Best way to define private methods for a class in Objective-C

There isn't really a "private method" in Objective-C, if the runtime can work out which implementation to use it will do it. But that's not to say that there aren't methods which aren't part of the documented interface. For those methods I think that a category is fine. Rather than putting the @interface at the top of the .m file like your point 2, I'd put it into its own .h file. A convention I follow (and have seen elsewhere, I think it's an Apple convention as Xcode now gives automatic support for it) is to name such a file after its class and category with a + separating them, so @interface GLObject (PrivateMethods) can be found in GLObject+PrivateMethods.h. The reason for providing the header file is so that you can import it in your unit test classes :-).

By the way, as far as implementing/defining methods near the end of the .m file is concerned, you can do that with a category by implementing the category at the bottom of the .m file:

@implementation GLObject(PrivateMethods)
- (void)secretFeature;

or with a class extension (the thing you call an "empty category"), just define those methods last. Objective-C methods can be defined and used in any order in the implementation, so there's nothing to stop you putting the "private" methods at the end of the file.

Even with class extensions I will often create a separate header (GLObject+Extension.h) so that I can use those methods if required, mimicking "friend" or "protected" visibility.

Since this answer was originally written, the clang compiler has started doing two passes for Objective-C methods. This means you can avoid declaring your "private" methods completely, and whether they're above or below the calling site they'll be found by the compiler.

How do I resolve the " Address already in use: JVM_Bind" error?

The port is already being used by some other process as @Diego Pino said u can use lsof on unix to locate the process and kill the respective one, if you are on windows use netstat -ano to get all the pids of the process and the ports that everyone acquires. search for your intended port and kill.

to be very easy just restart your machine , if thats possible :)

Git push existing repo to a new and different remote repo server?

  1. Create a new repo at github.
  2. Clone the repo from fedorahosted to your local machine.
  3. git remote rename origin upstream
  4. git remote add origin URL_TO_GITHUB_REPO
  5. git push origin master

Now you can work with it just like any other github repo. To pull in patches from upstream, simply run git pull upstream master && git push origin master.

Convert double to Int, rounded down

If you explicitly cast double to int, the decimal part will be truncated. For example:

int x = (int) 4.97542;   //gives 4 only
int x = (int) 4.23544;   //gives 4 only

Moreover, you may also use Math.floor() method to round values in case you want double value in return.

Should ol/ul be inside <p> or outside?

The second. The first is invalid.

  • A paragraph cannot contain a list.
  • A list cannot contain a paragraph unless that paragraph is contained entirely within a single list item.

A browser will handle it like so:

<!-- Start of paragraph -->
<!-- Start of ordered list. Paragraphs cannot contain lists. Insert </p> -->
<li>first element</li></ol>
<!-- A list item element. End of list -->
<!-- End of paragraph, but not inside paragraph, discard this tag to recover from the error -->
<p>other textetxet</p>
<!-- Another paragraph -->

php date validation

I know this is an older post, but I've developed the following function for validating a date:

function IsDateTime($aDateTime) {
    try {
        $fTime = new DateTime($aDateTime);
        $fTime->format('m/d/Y H:i:s');
        return true;
    catch (Exception $e) {
        return false;

Java serialization - local class incompatible

@DanielChapman gives a good explanation of serialVersionUID, but no solution. the solution is this: run the serialver program on all your old classes. put these serialVersionUID values in your current versions of the classes. as long as the current classes are serial compatible with the old versions, you should be fine. (note for future code: you should always have a serialVersionUID on all Serializable classes)

if the new versions are not serial compatible, then you need to do some magic with a custom readObject implementation (you would only need a custom writeObject if you were trying to write new class data which would be compatible with old code). generally speaking adding or removing class fields does not make a class serial incompatible. changing the type of existing fields usually will.

Of course, even if the new class is serial compatible, you may still want a custom readObject implementation. you may want this if you want to fill in any new fields which are missing from data saved from old versions of the class (e.g. you have a new List field which you want to initialize to an empty list when loading old class data).

How do I do an OR filter in a Django query?

It is worth to note that it's possible to add Q expressions.

For example:

from django.db.models import Q

query = Q(first_name='mark')
query.add(Q(email='[email protected]'), Q.OR)
query.add(Q(last_name='doe'), Q.AND)

queryset = User.objects.filter(query)

This ends up with a query like :

(first_name = 'mark' or email = '[email protected]') and last_name = 'doe'

This way there is no need to deal with or operators, reduce's etc.

Sending multipart/formdata with jQuery.ajax

Look at my code, it does the job for me

$( '#formId' )
  .submit( function( e ) {
    $.ajax( {
      url: 'FormSubmitUrl',
      type: 'POST',
      data: new FormData( this ),
      processData: false,
      contentType: false
    } );
  } );

How to use paginator from material angular?

This issue is resolved after spending few hours and i got it working. which is believe is the simplest way to solve the pagination with angular material. - Do first start by working on (component.html) file

 <mat-paginator [pageSizeOptions]="[2, 5, 10, 15, 20]" showFirstLastButtons>

and do in the (component.ts) file

 import { MatPaginator } from '@angular/material/paginator';
 import { Component, OnInit, ViewChild } from '@angular/core';

 export interface UserData {
 full_name: string;
 email: string;
 mob_number: string;

 export class UserManagementComponent implements OnInit{
  dataSource : MatTableDataSource<UserData>;

  @ViewChild(MatPaginator) paginator: MatPaginator;


    ngOnInit() { }

   public userList() {

      response => {

      this.dataSource = new MatTableDataSource<UserData>(response['results']);
      this.dataSource.paginator = this.paginator;


      error => {});



Remember Must import the pagination module in your currently working module(module.ts) file.

  import {MatPaginatorModule} from '@angular/material/paginator';

      imports: [MatPaginatorModule]

Hope it will Work for you.

Why are static variables considered evil?

I have just summarized some of the points made in the answers. If you find anything wrong please feel free to correct it.

Scaling: We have exactly one instance of a static variable per JVM. Suppose we are developing a library management system and we decided to put the name of book a static variable as there is only one per book. But if system grows and we are using multiple JVMs then we dont have a way to figure out which book we are dealing with?

Thread-Safety: Both instance variable and static variable need to be controlled when used in multi threaded environment. But in case of an instance variable it does not need protection unless it is explicitly shared between threads but in case of a static variable it is always shared by all the threads in the process.

Testing: Though testable design does not equal to good design but we will rarely observe a good design that is not testable. As static variables represent global state and it gets very difficult to test them.

Reasoning about state: If I create a new instance of a class then we can reason about the state of this instance but if it is having static variables then it could be in any state. Why? Because it is possible that the static variable has been modified by some different instance as static variable is shared across instances.

Serialization: Serialization also does not work well with them.

Creation and destruction: Creation and destruction of static variables can not be controlled. Usually they are created and destroyed at program loading and unloading time. It means they are bad for memory management and also add up the initialization time at start up.

But what if we really need them?

But sometimes we may have a genuine need of them. If we really feel the need of many static variables that are shared across the application then one option is to make use of Singleton Design pattern which will have all these variables. Or we can create some object which will have these static variable and can be passed around.

Also if the static variable is marked final it becomes a constant and value assigned to it once cannot be changed. It means it will save us from all the problems we face due to its mutability.

How to select element using XPATH syntax on Selenium for Python?


<div id='a'>
    <a class='click'>abc</a>

You could use the XPATH as :



<a class="click">abc</a>

That said your Python code should be as :


Inserting data into a temporary table

insert into #temptable (col1, col2, col3)
select col1, col2, col3 from othertable

Note that this is considered poor practice:

insert into #temptable 
select col1, col2, col3 from othertable

If the definition of the temp table were to change, the code could fail at runtime.

Copying from one text file to another using Python

readlines() reads the entire input file into a list and is not a good performer. Just iterate through the lines in the file. I used 'with' on output.txt so that it is automatically closed when done. That's not needed on 'list1.txt' because it will be closed when the for loop ends.

#!/usr/bin/env python
with open('output.txt', 'a') as f1:
    for line in open('list1.txt'):
        if 'tests/file/myword' in line:

eclipse stuck when building workspace

I have this problem whe I have too much maven projects open at once. What I tend to do is:

  • Restart eclipse (sometimes I need to kill eclipse)
  • Disable automatic build immediatly (project > uncheck Build automatically)
  • Right click the project(s) I want to have rebuild
  • Close unrelated projects
  • Re-enable automatic build

This enables a functioning rebuild in 99% off the cases in my workspace.

How to fix the session_register() deprecated issue?

Don't use it. The description says:

Register one or more global variables with the current session.

Two things that came to my mind:

  1. Using global variables is not good anyway, find a way to avoid them.
  2. You can still set variables with $_SESSION['var'] = "value".

See also the warnings from the manual:

If you want your script to work regardless of register_globals, you need to instead use the $_SESSION array as $_SESSION entries are automatically registered. If your script uses session_register(), it will not work in environments where the PHP directive register_globals is disabled.

This is pretty important, because the register_globals directive is set to False by default!


This registers a global variable. If you want to register a session variable from within a function, you need to make sure to make it global using the global keyword or the $GLOBALS[] array, or use the special session arrays as noted below.


If you are using $_SESSION (or $HTTP_SESSION_VARS), do not use session_register(), session_is_registered(), and session_unregister().


As @Musa comments it, it seems that the reason is that:

Postman doesn't care about SOP, it's a dev tool not a browser

By the way here's a chrome extension in order to make it work on your browser (this one is for chrome, but you can find either for FF or Safari).

Check here if you want to learn more about Cross-Origin and why it's working for extensions.

TSQL CASE with if comparison in SELECT statement

Should be:

SELECT registrationDate, 
        WHEN COUNT(*)< 2 THEN 'Ama'
        WHEN COUNT(*)< 5 THEN 'SemiAma' 
        WHEN COUNT(*)< 7 THEN 'Good'  
        WHEN COUNT(*)< 9 THEN 'Better' 
        WHEN COUNT(*)< 12 THEN 'Best'
        ELSE 'Outstanding'
        END as a FROM Articles 
        WHERE Articles.userId = Users.userId) as ranking,
        (SELECT COUNT(*) 
        FROM Articles 
        WHERE userId = Users.userId) as articleNumber,
hobbies, etc...

Why is it not advisable to have the database and web server on the same machine?

An additional concern is that databases like to take up all the available memory and hold it in reserve for when it wants to use it. You can force it to limit the memory but this can considerably slow data access.

Convert Java object to XML string

I took the JAXB.marshal implementation and added jaxb.fragment=true to remove the XML prolog. This method can handle objects even without the XmlRootElement annotation. This also throws the unchecked DataBindingException.

public static String toXmlString(Object o) {
    try {
        Class<?> clazz = o.getClass();
        JAXBContext context = JAXBContext.newInstance(clazz);
        Marshaller marshaller = context.createMarshaller();
        marshaller.setProperty(Marshaller.JAXB_FRAGMENT, true); // remove xml prolog
        marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true); // formatted output

        final QName name = new QName(Introspector.decapitalize(clazz.getSimpleName()));
        JAXBElement jaxbElement = new JAXBElement(name, clazz, o);

        StringWriter sw = new StringWriter();
        marshaller.marshal(jaxbElement, sw);
        return sw.toString();

    } catch (JAXBException e) {
        throw new DataBindingException(e);

If the compiler warning bothers you, here's the templated, two parameter version.

public static <T> String toXmlString(T o, Class<T> clazz) {
    try {
        JAXBContext context = JAXBContext.newInstance(clazz);
        Marshaller marshaller = context.createMarshaller();
        marshaller.setProperty(Marshaller.JAXB_FRAGMENT, true); // remove xml prolog
        marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true); // formatted output

        QName name = new QName(Introspector.decapitalize(clazz.getSimpleName()));
        JAXBElement jaxbElement = new JAXBElement<>(name, clazz, o);

        StringWriter sw = new StringWriter();
        marshaller.marshal(jaxbElement, sw);
        return sw.toString();

    } catch (JAXBException e) {
        throw new DataBindingException(e);

Populate a Drop down box from a mySQL table in PHP

Below is the code for drop down using MySql and PHP:

$sql="Select PcID from PC"
echo "<select name=\"pcid\">"; 
echo "<option size =30 ></option>";
while($row = mysql_fetch_array($q)) 
echo "<option value='".$row['PcID']."'>".$row['PcID']."</option>"; 
echo "</select>";

Change background position with jQuery

$('#submenu li').hover(function(){
    $('#carousel').css('backgroundPosition', newValue);

How can I remove item from querystring in using c#?

My personal preference here is rewriting the query or working with a namevaluecollection at a lower point, but there are times where the business logic makes neither of those very helpful and sometimes reflection really is what you need. In those circumstances you can just turn off the readonly flag for a moment like so:

// reflect to readonly property
PropertyInfo isreadonly = typeof(System.Collections.Specialized.NameValueCollection).GetProperty("IsReadOnly", BindingFlags.Instance | BindingFlags.NonPublic);

// make collection editable
isreadonly.SetValue(this.Request.QueryString, false, null);

// remove

// modify
this.Request.QueryString.Set("bar", "123");

// make collection readonly again
isreadonly.SetValue(this.Request.QueryString, true, null);

No provider for TemplateRef! (NgIf ->TemplateRef)

You missed the * in front of NgIf (like we all have, dozens of times):

<div *ngIf="answer.accepted">&#10004;</div>

Without the *, Angular sees that the ngIf directive is being applied to the div element, but since there is no * or <template> tag, it is unable to locate a template, hence the error.

If you get this error with Angular v5:

Error: StaticInjectorError[TemplateRef]:
    NullInjectorError: No provider for TemplateRef!

You may have <template>...</template> in one or more of your component templates. Change/update the tag to <ng-template>...</ng-template>.

A formula to copy the values from a formula to another column

you can use those functions together with iferror as a work around.


Extract csv file specific columns to list in Python

This looks like a problem with line endings in your code. If you're going to be using all these other scientific packages, you may as well use Pandas for the CSV reading part, which is both more robust and more useful than just the csv module:

import pandas
colnames = ['year', 'name', 'city', 'latitude', 'longitude']
data = pandas.read_csv('test.csv', names=colnames)

If you want your lists as in the question, you can now do:

names =
latitude = data.latitude.tolist()
longitude = data.longitude.tolist()

How to take backup of a single table in a MySQL database?

just use mysqldump -u root database table or if using with password mysqldump -u root -p pass database table

Can you "compile" PHP code and upload a binary-ish file, which will just be run by the byte code interpreter?

There are several "compilers" of PHP code. Most of them do not support all of PHP features, since these simply must be interpreted during run time.

We are using Phalanger - - that is supporting even those dirty PHP dynamic features, and still is able to compile them as .NET assembly, that can be distributed as a standalone DLL.

Creating an empty file in C#

File.WriteAllText("path", String.Empty);



Filter by Dates in SQL

WHERE dates BETWEEN (convert(datetime, '2012-12-12',110) AND (convert(datetime, '2012-12-12',110))

C# Debug - cannot start debugging because the debug target is missing

Try these:

  1. Make sure that output path of project is correct (Project > Properties > Build > Output path)

  2. Go in menu to Build > Configuration Manager, and check if your main/entry project has checked Build. If not, check it.

Vue js error: Component template should contain exactly one root element

if, for any reasons, you don't want to add a wrapper (in my first case it was for <tr/> components), you can use a functionnal component.

Instead of having a single components/MyCompo.vue you will have few files in a components/MyCompo folder :

  • components/MyCompo/index.js
  • components/MyCompo/File.vue
  • components/MyCompo/Avatar.vue

With this structure, the way you call your component won't change.

components/MyCompo/index.js file content :

import File from './File';
import Avatar from './Avatar';   

const commonSort=(a,b)=>b-a;

export default {
  functional: true,
  name: 'MyCompo',
  props: [ 'someProp', 'plopProp' ],
  render(createElement, context) {
    return [
        createElement( File, { props: Object.assign({light: true, sort: commonSort},context.props) } ),
        createElement( Avatar, { props: Object.assign({light: false, sort: commonSort},context.props) } )

And if you have some function or data used in both templates, passed them as properties and that's it !

I let you imagine building list of components and so much features with this pattern.

How do I execute a program using Maven?

In order to execute multiple programs, I also needed a profiles section:


This is then executable as:

mvn exec:exec -Ptraverse

Android get Current UTC time

see my answer here:

How can I get the current date and time in UTC or GMT in Java?

I've fully tested it by changing the timezones on the emulator

How can we store into an NSDictionary? What is the difference between NSDictionary and NSMutableDictionary?

The NSDictionary and NSMutableDictionary docs are probably your best bet. They even have some great examples on how to do various things, like...

...create an NSDictionary

NSArray *keys = [NSArray arrayWithObjects:@"key1", @"key2", nil];
NSArray *objects = [NSArray arrayWithObjects:@"value1", @"value2", nil];
NSDictionary *dictionary = [NSDictionary dictionaryWithObjects:objects 

...iterate over it

for (id key in dictionary) {
    NSLog(@"key: %@, value: %@", key, [dictionary objectForKey:key]);

...make it mutable

NSMutableDictionary *mutableDict = [dictionary mutableCopy];

Note: historic version before 2010: [[dictionary mutableCopy] autorelease]

...and alter it

[mutableDict setObject:@"value3" forKey:@"key3"];

...then store it to a file

[mutableDict writeToFile:@"path/to/file" atomically:YES];

...and read it back again

NSMutableDictionary *anotherDict = [NSMutableDictionary dictionaryWithContentsOfFile:@"path/to/file"]; a value

NSString *x = [anotherDict objectForKey:@"key1"];

...check if a key exists

if ( [anotherDict objectForKey:@"key999"] == nil ) NSLog(@"that key is not there");

...use scary futuristic syntax

From 2014 you can actually just type dict[@"key"] rather than [dict objectForKey:@"key"]

Laravel use same form for create and edit

you can use @$variable in your single blade file for create and edit. it will not through error when variable not defined.

<input name="name" value="@{{$your_variable->name}}">

How to query values from xml nodes?

Try this:

SELECT RawXML.value('(/GrobXmlFile//Grob//ReportHeader//OrganizationReportReferenceIdentifier/node())[1]','varchar(50)') AS ReportIdentifierNumber,
       RawXML.value('(/GrobXmlFile//Grob//ReportHeader//OrganizationNumber/node())[1]','int') AS OrginazationNumber
FROM Batches

npm install hangs

I am behind a corporate proxy, so I usually use an intermediate proxy to enable NTLM authentication.

I had hangs problem with npm install when using CNTLM proxy. With NTLM-APS (a similar proxy) the hangs were gone.

What is the difference between function and procedure in PL/SQL?

  1. we can call a stored procedure inside stored Procedure,Function within function ,StoredProcedure within function but we can not call function within stored procedure.
  2. we can call function inside select statement.
  3. We can return value from function without passing output parameter as a parameter to the stored procedure.

This is what the difference i found. Please let me know if any .

Convert a timedelta to days, hours and minutes

Here is a little function I put together to do this right down to microseconds:

def tdToDict(td:datetime.timedelta) -> dict:
    def __t(t, n):
        if t < n: return (t, 0)
        v = t//n
        return (t -  (v * n), v)
    (s, h) = __t(td.seconds, 3600)
    (s, m) = __t(s, 60)    
    (micS, milS) = __t(td.microseconds, 1000)

    return {
         'days': td.days
        ,'hours': h
        ,'minutes': m
        ,'seconds': s
        ,'milliseconds': milS
        ,'microseconds': micS

Here is a version that returns a tuple:

# usage: (_d, _h, _m, _s, _mils, _mics) = tdTuple(td)
def tdTuple(td:datetime.timedelta) -> tuple:
    def _t(t, n):
        if t < n: return (t, 0)
        v = t//n
        return (t -  (v * n), v)
    (s, h) = _t(td.seconds, 3600)
    (s, m) = _t(s, 60)    
    (mics, mils) = _t(td.microseconds, 1000)
    return (td.days, h, m, s, mics, mils)

Get current URL path in PHP

function current_url()
    $url      = "http://" . $_SERVER['HTTP_HOST'] . $_SERVER['REQUEST_URI'];
    $validURL = str_replace("&", "&amp", $url);
    return $validURL;
//echo "page URL is : ".current_url();

$offer_url = current_url();



if ($offer_url == "checking url name") {
?> <p> hi this is manip5595 </p>


How to remove items from a list while iterating?

The answers suggesting list comprehensions are ALMOST correct -- except that they build a completely new list and then give it the same name the old list as, they do NOT modify the old list in place. That's different from what you'd be doing by selective removal, as in @Lennart's suggestion -- it's faster, but if your list is accessed via multiple references the fact that you're just reseating one of the references and NOT altering the list object itself can lead to subtle, disastrous bugs.

Fortunately, it's extremely easy to get both the speed of list comprehensions AND the required semantics of in-place alteration -- just code:

somelist[:] = [tup for tup in somelist if determine(tup)]

Note the subtle difference with other answers: this one is NOT assigning to a barename - it's assigning to a list slice that just happens to be the entire list, thereby replacing the list contents within the same Python list object, rather than just reseating one reference (from previous list object to new list object) like the other answers.

How to terminate the script in JavaScript?

Not applicable in most circumstances, but I had lots of async scripts running in the browser and as a hack I do


to stop everything.

A terminal command for a rooted Android to remount /System as read/write

Instead of

mount -o rw,remount /system/


mount -o rw,remount /system

mind the '/' at the end of the command. you ask why this matters? /system/ is the directory under /system while /system is the volume name.

Posting a File and Associated Data to a RESTful WebService preferably as JSON

I asked a similar question here:

How do I upload a file with metadata using a REST web service?

You basically have three choices:

  1. Base64 encode the file, at the expense of increasing the data size by around 33%, and add processing overhead in both the server and the client for encoding/decoding.
  2. Send the file first in a multipart/form-data POST, and return an ID to the client. The client then sends the metadata with the ID, and the server re-associates the file and the metadata.
  3. Send the metadata first, and return an ID to the client. The client then sends the file with the ID, and the server re-associates the file and the metadata.

Ruby: Merging variables in to a string

["The", animal, action, "the", second_animal].join(" ")

is another way to do it.

Get webpage contents with Python?

If you ask me. try this one

import urllib2
resp = urllib2.urlopen('')

and read the normal way ie

page =

Good luck though

Should you choose the MONEY or DECIMAL(x,y) datatypes in SQL Server?

As a counter point to the general thrust of the other answers. See The Many Benefits of Money…Data Type! in SQLCAT's Guide to Relational Engine

Specifically I would point out the following

Working on customer implementations, we found some interesting performance numbers concerning the money data type. For example, when Analysis Services was set to the currency data type (from double) to match the SQL Server money data type, there was a 13% improvement in processing speed (rows/sec). To get faster performance within SQL Server Integration Services (SSIS) to load 1.18 TB in under thirty minutes, as noted in SSIS 2008 - world record ETL performance, it was observed that changing the four decimal(9,2) columns with a size of 5 bytes in the TPC-H LINEITEM table to money (8 bytes) improved bulk inserting speed by 20% ... The reason for the performance improvement is because of SQL Server’s Tabular Data Stream (TDS) protocol, which has the key design principle to transfer data in compact binary form and as close as possible to the internal storage format of SQL Server. Empirically, this was observed during the SSIS 2008 - world record ETL performance test using Kernrate; the protocol dropped significantly when the data type was switched to money from decimal. This makes the transfer of data as efficient as possible. A complex data type needs additional parsing and CPU cycles to handle than a fixed-width type.

So the answer to the question is "it depends". You need to be more careful with certain arithmetical operations to preserve precision but you may find that performance considerations make this worthwhile.

Find (and kill) process locking port 3000 on Mac

You should try this, This technique is OS Independent.

In side your application there is a folder called tmp, inside that there is an another folder called pids. That file contains the server pid file. Simply delete that file. port automatically kill itself.

I think this is the easy way.

What does file:///android_asset/www/index.html mean?

It took me more than 4 hours to fix this problem. I followed the guide from

I'm using Android Studio (Eclipse with ADT could not work properly because of the build problem).

Solution that worked for me:

  1. I put the /assets/www/index.html under app/src/main/assets directory. (take care AndroidStudio has different perspectives like Project or Android)

  2. use super.loadUrl("file:///android_asset/www/index.html"); instead of super.loadUrl("file:///android_assets/www/index.html"); (no s)

Is there a better way to iterate over two lists, getting one element from each list for each iteration?

Good to see lots of love for zip in the answers here.

However it should be noted that if you are using a python version before 3.0, the itertools module in the standard library contains an izip function which returns an iterable, which is more appropriate in this case (especially if your list of latt/longs is quite long).

In python 3 and later zip behaves like izip.

How to center a "position: absolute" element

Just use display: flex and justify-content: center on the parent element

body {
    text-align: center;

#slideshowWrapper {
    margin-top: 50px;
    text-align: center;

ul#slideshow {
    list-style: none;
    position: relative;
    margin: auto;
    display: flex;
    justify-content: center;

ul#slideshow li {
    position: absolute;

ul#slideshow li img {
    border: 1px solid #ccc;
    padding: 4px;
    height: 100px;
   <div id="slideshowWrapper">
      <ul id="slideshow">
         <li><img src="*300?technology" alt="Dummy 1" /></li>
         <li><img src="*301?technology" alt="Dummy 2" /></li>

<!-- Images from Unsplash-->

You can find this solution in JSFIDDLE

How to define partitioning of DataFrame?

In Spark < 1.6 If you create a HiveContext, not the plain old SqlContext you can use the HiveQL DISTRIBUTE BY colX... (ensures each of N reducers gets non-overlapping ranges of x) & CLUSTER BY colX... (shortcut for Distribute By and Sort By) for example;

hiveCtx.sql("select * from partitionMe DISTRIBUTE BY accountId SORT BY accountId, date")

Not sure how this fits in with Spark DF api. These keywords aren't supported in the normal SqlContext (note you dont need to have a hive meta store to use the HiveContext)

EDIT: Spark 1.6+ now has this in the native DataFrame API

How can I insert into a BLOB column from an insert statement in sqldeveloper?

Yes, it's possible, e.g. using the implicit conversion from RAW to BLOB:

insert into blob_fun values(1, hextoraw('453d7a34'));

453d7a34 is a string of hexadecimal values, which is first explicitly converted to the RAW data type and then inserted into the BLOB column. The result is a BLOB value of 4 bytes.

Angular2 - Input Field To Accept Only Numbers

I know this is an old question, but since this is a common funcionality, I want to share the modifications I've made:

  • Custom decimal separator (point or comma)
  • Support for integers only or integer and decimals
  • Support for positive numbers only or positives and negatives
  • Validate minus sign(-) is in the beginning
  • Support to mouse pasting (with some limitation though
  • Support for Mac command key
  • Replace strings like ".33" and "33." for the correct versions: 0.33 and 33.0

    import { Directive, ElementRef, HostListener, Input } from '@angular/core';
    @Directive({ selector: '[NumbersOnly]' })
    export class NumbersOnly { 
        @Input() allowDecimals: boolean = true;
        @Input() allowSign: boolean = false;
        @Input() decimalSeparator: string = '.';
        previousValue: string = '';
        // --------------------------------------
        //  Regular expressions
        integerUnsigned: string = '^[0-9]*$';
        integerSigned: string = '^-?[0-9]+$';
        decimalUnsigned: string = '^[0-9]+(.[0-9]+)?$';
        decimalSigned: string = '^-?[0-9]+(.[0-9]+)?$';
         * Class constructor
         * @param hostElement
        constructor(private hostElement: ElementRef) { }
         * Event handler for host's change event
         * @param e
        @HostListener('change', ['$event']) onChange(e) {
     * Event handler for host's paste event
     * @param e
    @HostListener('paste', ['$event']) onPaste(e) {
        // get and validate data from clipboard
        let value = e.clipboardData.getData('text/plain');
     * Event handler for host's keydown event
     * @param event
    @HostListener('keydown', ['$event']) onKeyDown(e: KeyboardEvent) {
        let cursorPosition: number =['selectionStart'];
        let originalValue: string =['value'];
        let key: string = this.getName(e);
        let controlOrCommand = (e.ctrlKey === true || e.metaKey === true);
        let signExists = originalValue.includes('-');
        let separatorExists = originalValue.includes(this.decimalSeparator);
        // allowed keys apart from numeric characters
        let allowedKeys = [
            'Backspace', 'ArrowLeft', 'ArrowRight', 'Escape', 'Tab'
        // when decimals are allowed, add
        // decimal separator to allowed codes when
        // its position is not close to the the sign (-. and .-)
        let separatorIsCloseToSign = (signExists && cursorPosition <= 1);
        if (this.allowDecimals && !separatorIsCloseToSign && !separatorExists) {
            if (this.decimalSeparator == '.')
        // when minus sign is allowed, add its
        // key to allowed key only when the
        // cursor is in the first position, and
        // first character is different from
        // decimal separator
        let firstCharacterIsSeparator = (originalValue.charAt(0) != this.decimalSeparator);
        if (this.allowSign && !signExists &&
            firstCharacterIsSeparator && cursorPosition == 0) {
        // allow some non-numeric characters
        if (allowedKeys.indexOf(key) != -1 ||
            // Allow: Ctrl+A and Command+A
            (key == 'a' && controlOrCommand) ||
            // Allow: Ctrl+C and Command+C
            (key == 'c' && controlOrCommand) ||
            // Allow: Ctrl+V and Command+V
            (key == 'v' && controlOrCommand) ||
            // Allow: Ctrl+X and Command+X
            (key == 'x' && controlOrCommand)) {
            // let it happen, don't do anything
        // save value before keydown event
        this.previousValue = originalValue;
        // allow number characters only
        let isNumber = (new RegExp(this.integerUnsigned)).test(key);
        if (isNumber) return; else e.preventDefault();
     * Test whether value is a valid number or not
     * @param value
    validateValue(value: string): void {
        // choose the appropiate regular expression
        let regex: string;
        if (!this.allowDecimals && !this.allowSign) regex = this.integerUnsigned;
        if (!this.allowDecimals && this.allowSign) regex = this.integerSigned;
        if (this.allowDecimals && !this.allowSign) regex = this.decimalUnsigned;
        if (this.allowDecimals &&  this.allowSign) regex = this.decimalSigned;
        // when a numbers begins with a decimal separator,
        // fix it adding a zero in the beginning
        let firstCharacter = value.charAt(0);
        if (firstCharacter == this.decimalSeparator)
            value = 0 + value;
        // when a numbers ends with a decimal separator,
        // fix it adding a zero in the end
        let lastCharacter = value.charAt(value.length-1);
        if (lastCharacter == this.decimalSeparator)
            value = value + 0;
        // test number with regular expression, when
        // number is invalid, replace it with a zero
        let valid: boolean = (new RegExp(regex)).test(value);
        this.hostElement.nativeElement['value'] = valid ? value : 0;
     * Get key's name
     * @param e
    getName(e): string {
        if (e.key) {
            return e.key;
        } else {
            // for old browsers
            if (e.keyCode && String.fromCharCode) {
                switch (e.keyCode) {
                    case   8: return 'Backspace';
                    case   9: return 'Tab';
                    case  27: return 'Escape';
                    case  37: return 'ArrowLeft';
                    case  39: return 'ArrowRight';
                    case 188: return ',';
                    case 190: return '.';
                    case 109: return '-'; // minus in numbpad
                    case 173: return '-'; // minus in alphabet keyboard in firefox
                    case 189: return '-'; // minus in alphabet keyboard in chrome
                    default: return String.fromCharCode(e.keyCode);


 <input NumbersOnly

std::string to char*

You can make it using iterator.

std::string str = "string";
std::string::iterator p=str.begin();
char* chr = &(*p);

Good luck.

Difference between scaling horizontally and vertically for databases

Scaling horizontally ===> Thousands of minions will do the work together for you.

Scaling vertically ===> One big hulk will do all the work for you.

enter image description here

Batch file include external file for variables

:: savevars.bat
:: Use $ to prefix any important variable to save it for future runs.


REM Load variables
IF EXIST config.txt FOR /F "delims=" %%A IN (config.txt) DO SET "%%A"

REM Change variables
    SET $RunCount=1
) ELSE SET /A $RunCount+=1

REM Display variables

REM Save variables
SET $>config.txt






The technique outlined above can also be used to share variables among multiple batch files.


Combining two expressions (Expression<Func<T, bool>>)

Well, you can use Expression.AndAlso / OrElse etc to combine logical expressions, but the problem is the parameters; are you working with the same ParameterExpression in expr1 and expr2? If so, it is easier:

var body = Expression.AndAlso(expr1.Body, expr2.Body);
var lambda = Expression.Lambda<Func<T,bool>>(body, expr1.Parameters[0]);

This also works well to negate a single operation:

static Expression<Func<T, bool>> Not<T>(
    this Expression<Func<T, bool>> expr)
    return Expression.Lambda<Func<T, bool>>(
        Expression.Not(expr.Body), expr.Parameters[0]);

Otherwise, depending on the LINQ provider, you might be able to combine them with Invoke:

// OrElse is very similar...
static Expression<Func<T, bool>> AndAlso<T>(
    this Expression<Func<T, bool>> left,
    Expression<Func<T, bool>> right)
    var param = Expression.Parameter(typeof(T), "x");
    var body = Expression.AndAlso(
            Expression.Invoke(left, param),
            Expression.Invoke(right, param)
    var lambda = Expression.Lambda<Func<T, bool>>(body, param);
    return lambda;

Somewhere, I have got some code that re-writes an expression-tree replacing nodes to remove the need for Invoke, but it is quite lengthy (and I can't remember where I left it...)

Generalized version that picks the simplest route:

static Expression<Func<T, bool>> AndAlso<T>(
    this Expression<Func<T, bool>> expr1,
    Expression<Func<T, bool>> expr2)
    // need to detect whether they use the same
    // parameter instance; if not, they need fixing
    ParameterExpression param = expr1.Parameters[0];
    if (ReferenceEquals(param, expr2.Parameters[0]))
        // simple version
        return Expression.Lambda<Func<T, bool>>(
            Expression.AndAlso(expr1.Body, expr2.Body), param);
    // otherwise, keep expr1 "as is" and invoke expr2
    return Expression.Lambda<Func<T, bool>>(
            Expression.Invoke(expr2, param)), param);

Starting from .NET 4.0, there is the ExpressionVisitor class which allows you to build expressions that are EF safe.

    public static Expression<Func<T, bool>> AndAlso<T>(
        this Expression<Func<T, bool>> expr1,
        Expression<Func<T, bool>> expr2)
        var parameter = Expression.Parameter(typeof (T));

        var leftVisitor = new ReplaceExpressionVisitor(expr1.Parameters[0], parameter);
        var left = leftVisitor.Visit(expr1.Body);

        var rightVisitor = new ReplaceExpressionVisitor(expr2.Parameters[0], parameter);
        var right = rightVisitor.Visit(expr2.Body);

        return Expression.Lambda<Func<T, bool>>(
            Expression.AndAlso(left, right), parameter);

    private class ReplaceExpressionVisitor
        : ExpressionVisitor
        private readonly Expression _oldValue;
        private readonly Expression _newValue;

        public ReplaceExpressionVisitor(Expression oldValue, Expression newValue)
            _oldValue = oldValue;
            _newValue = newValue;

        public override Expression Visit(Expression node)
            if (node == _oldValue)
                return _newValue;
            return base.Visit(node);

How do I integrate Ajax with Django applications?

I am writing this because the accepted answer is pretty old, it needs a refresher.

So this is how I would integrate Ajax with Django in 2019 :) And lets take a real example of when we would need Ajax :-

Lets say I have a model with registered usernames and with the help of Ajax I wanna know if a given username exists.


<p id="response_msg"></p> 
<form id="username_exists_form" method='GET'>
      Name: <input type="username" name="username" />
      <button type='submit'> Check </button>           


    var username = $(this).find('input').val();
          {'username': username},   
          function(response){ $('#response_msg').text(response.msg); }

from django.contrib import admin
from django.urls import path
from . import views

urlpatterns = [
    path('exists/', views.username_exists, name='exists'),

def username_exists(request):
    data = {'msg':''}   
    if request.method == 'GET':
        username = request.GET.get('username').lower()
        exists = Usernames.objects.filter(name=username).exists()
        if exists:
            data['msg'] = username + ' already exists.'
            data['msg'] = username + ' does not exists.'
    return JsonResponse(data)

Also render_to_response which is deprecated and has been replaced by render and from Django 1.7 onwards instead of HttpResponse we use JsonResponse for ajax response. Because it comes with a JSON encoder, so you don’t need to serialize the data before returning the response object but HttpResponse is not deprecated.

Ansible Ignore errors in tasks and fail at end of the playbook if any tasks had errors

Use Fail module.

  1. Use ignore_errors with every task that you need to ignore in case of errors.
  2. Set a flag (say, result = false) whenever there is a failure in any task execution
  3. At the end of the playbook, check if flag is set, and depending on that, fail the execution
- fail: msg="The execution has failed because of errors."
  when: flag == "failed"


Use register to store the result of a task like you have shown in your example. Then, use a task like this:

- name: Set flag
  set_fact: flag = failed
  when: "'FAILED' in command_result.stderr"

hasOwnProperty in JavaScript

hasOwnProperty() is a nice property to validate object keys. Example:

var obj = {a:1, b:2};

obj.hasOwnProperty('a') // true

Location of hibernate.cfg.xml in project?

Another reason why this exception occurs is if you call the configure method twice on a Configuration or AnnotatedConfiguration object like this -

AnnotationConfiguration config = new AnnotationConfiguration();
//Use this if config files are in src folder
//Use this if config files are in a subfolder of src, such as "resources"

Btw, this project structure is inside eclipse.

How can I convert an image into a Base64 string?

Convert an image to Base64 string in Android:

ByteArrayOutputStream baos = new ByteArrayOutputStream();
Bitmap bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.yourimage);
bitmap.compress(Bitmap.CompressFormat.JPEG, 100, baos);
byte[] imageBytes = baos.toByteArray();
String imageString = Base64.encodeToString(imageBytes, Base64.DEFAULT);

How to solve ERR_CONNECTION_REFUSED when trying to connect to localhost running IISExpress - Error 502 (Cannot debug from Visual Studio)?

I solved this problem by starting Visual Studio with Run as administrator. This is also required if you want to publish your project to the local IIS.

To set this permanently:-

  1. Right-click on the Visual Studio icon
  2. Select Properties
  3. Click Advanced
  4. Ensure Run as administrator is checked-on
  5. Click on OK all the way out.
  6. Start Visual Studio, load your project and start debugging

How to get the primary IP address of the local machine on Linux and OS X?

You can also get IP version 4 address of eth0 by using this command in linux

/sbin/ip -4 -o addr show dev eth0| awk '{split($4,a,"/");print a[1]}'

Output will be like this

[root@localhost Sathish]# /sbin/ip -4 -o addr show dev eth0| awk '{split($4,a,"/");print a[1]}'

Java: How to resolve java.lang.NoClassDefFoundError: javax/xml/bind/JAXBException

For me in Java 11 and gradle this is what worked out:

plugins {
      id 'java'

dependencies {
      runtimeOnly 'javax.xml.bind:jaxb-api:2.3.1'

Uninstall all installed gems, in OSX?

Rubygems >= 2.1.0

gem uninstall -aIx

a removes all versions
I ignores dependencies
x includes executables

Rubgems < 2.1.0

for i in `gem list --no-versions`; do gem uninstall -aIx $i; done

Solving Quadratic Equation

This line is causing problems:


x/2*a is interpreted as (x/2)*a. You need more parentheses:

(-b + math.sqrt(b**2 - 4*a*c)) / (2 * a)

Also, if you're already storing d, why not use it?

x = (-b + math.sqrt(d)) / (2 * a)

Add a column in a table in HIVE QL

You cannot add a column with a default value in Hive. You have the right syntax for adding the column ALTER TABLE test1 ADD COLUMNS (access_count1 int);, you just need to get rid of default sum(max_count). No changes to that files backing your table will happen as a result of adding the column. Hive handles the "missing" data by interpreting NULL as the value for every cell in that column.

So now your have the problem of needing to populate the column. Unfortunately in Hive you essentially need to rewrite the whole table, this time with the column populated. It may be easier to rerun your original query with the new column. Or you could add the column to the table you have now, then select all of its columns plus value for the new column.

You also have the option to always COALESCE the column to your desired default and leave it NULL for now. This option fails when you want NULL to have a meaning distinct from your desired default. It also requires you to depend on always remembering to COALESCE.

If you are very confident in your abilities to deal with the files backing Hive, you could also directly alter them to add your default. In general I would recommend against this because most of the time it will be slower and more dangerous. There might be some case where it makes sense though, so I've included this option for completeness.

Does PHP have threading?

I have a PHP threading class that's been running flawlessly in a production environment for over two years now.

EDIT: This is now available as a composer library and as part of my MVC framework, Hazaar MVC.


Removing duplicate objects with Underscore for Javascript

If you're looking to remove duplicates based on an id you could do something like this:

var res = [
  {id: 1, content: 'heeey'},
  {id: 2, content: 'woah'}, 
  {id: 1, content:'foo'},
  {id: 1, content: 'heeey'},
var uniques =,function(doc){
  return grouped[0];

//[{id: 1, content: 'heeey'},{id: 2, content: 'woah'}]

Java random numbers using a seed

If you're giving the same seed, that's normal. That's an important feature allowing tests.

Check this to understand pseudo random generation and seeds:

Pseudorandom number generator

A pseudorandom number generator (PRNG), also known as a deterministic random bit generator DRBG, is an algorithm for generating a sequence of numbers that approximates the properties of random numbers. The sequence is not truly random in that it is completely determined by a relatively small set of initial values, called the PRNG's state, which includes a truly random seed.

If you want to have different sequences (the usual case when not tuning or debugging the algorithm), you should call the zero argument constructor which uses the nanoTime to try to get a different seed every time. This Random instance should of course be kept outside of your method.

Your code should probably be like this:

private Random generator = new Random();
double randomGenerator() {
    return generator.nextDouble()*0.5;

Postman - How to see request with headers and body data with variables substituted

Update 2018-12-12 - Chrome App v Chrome Plugin - Most recent updates at top

With the deprecation of the Postman Chrome App, assuming that you are now using the Postman Native App, the options are now:

  1. Hover over variables with mouse
  2. Generate "Code" button/link
  3. Postman Console

See below for full details on each option.

Personally, I still go for 2) Generate "Code" button/link as it allows me to see the variables without actually having to send.

Demo Request Demo Request

Demo Environment Demo Environment

1) Hover over variables with mouse Hover over variables with mouse

2) Generate "Code" button/link Generate "Code" button/link

3) Postman Console enter image description here

Update: 2016-06-03

Whilst the method described above does work, in practice, I now normally use the "Generate Code" link on the Postman Request screen. The generated code, no matter what code language you choose, contains the substituted variables. Hitting the "Generate Code" link is just faster, additionally, you can see the substituted variables without actually making the request.

Original Answer below

To see the substituted variables in the Headers and Body, you need to use Chrome Developer tools. To enable Chrome Developer Tools from within Postman do the following, as per

I have copied the instructions from the link above in case the link gets broken in the future:

  1. Type chrome://flags inside your Chrome URL window

  2. Search for “packed” or try to find the “Enable debugging for packed apps”

  3. Enable the setting

  4. Restart Chrome

You can access the Developer Tools window by right clicking anywhere inside Postman and selecting “inspect element”. You can also go to chrome://inspect/#apps and then click “inspect” just below requester.html under the Postman heading.

Once enabled, you can use the Network Tools tab for even more information on your requests or the console while writing test scripts. If something goes wrong with your test scripts, it’ll show up here.

Quickest way to compare two generic lists for differences

try this way:

var difList = list1.Where(a => !list2.Any(a1 => ==
            .Union(list2.Where(a => !list1.Any(a1 => ==;

VBA - Select columns using numbers?

In the example code below I use variables just to show how the command could be used for other situations.

FirstCol = 1
LastCol = FirstCol + 5
Range(Columns(FirstCol), Columns(LastCol)).Select

Proper way to renew distribution certificate for iOS

When your certificate expires, it simply disappears from the ‘Certificates, Identifier & Profiles’ section of Member Center. There is no ‘Renew’ button that allows you to renew your certificate. You can revoke a certificate and generate a new one before it expires. Or you can wait for it to expire and disappear, then generate a new certificate. In Apple's App Distribution Guide:

Replacing Expired Certificates

When your development or distribution certificate expires, remove it and request a new certificate in Xcode.

When your certificate expires or is revoked, any provisioning profile that made use of the expired/revoked certificate will be reflected as ‘Invalid’. You cannot build and sign any app using these invalid provisioning profiles. As you can imagine, I'd rather revoke and regenerate a certificate before it expires.

Q: If I do that then will all my live apps be taken down?

Apps that are already on the App Store continue to function fine. Again, in Apple's App Distribution Guide:

Important: Re-creating your development or distribution certificates doesn’t affect apps that you’ve submitted to the store nor does it affect your ability to update them.


Q: How to I properly renew it?

As mentioned above, there is no renewing of certificates. Follow the steps below to revoke and regenerate a new certificate, along with the affected provisioning profiles. The instructions have been updated for Xcode 8.3 and Xcode 9.

Step 1: Revoke the expiring certificate

Login to Member Center > Certificates, Identifiers & Profiles, select the expiring certificate. Take note of the expiry date of the certificate, and click the ‘Revoke’ button.

Select the expiring certificate and click the Revoke button

Step 2: (Optional) Remove the revoked certificate from your Keychain

Optionally, if you don't want to have the revoked certificate lying around in your system, you can delete them from your system. Unfortunately, the ‘Delete Certificate’ function in Xcode > Preferences > Accounts > [Apple ID] > Manage Certificates… seems to be always disabled, so we have to delete them manually using Keychain (/Applications/Utilities/Keychain

Optionally remove the revoked certificate using Keychain

Filter by ‘login’ Keychains and ‘Certificates’ Category. Locate the certificate that you've just revoked in Step 1.

Depending on the certificate that you've just revoked, search for either ‘Mac’ or ‘iPhone’. Mac App Store distribution certificates begin with “3rd Party Mac Developer”, and iOS App Store distribution certificates begin with “iPhone Distribution”.

You can locate the revoked certificate based on the team name, the type of certificate (Mac or iOS) and the expiry date of the certificate you've noted down in Step 1.

Step 3: Request a new certificate using Xcode

Under Xcode > Preferences > Accounts > [Apple ID] > Manage Certificates…, click on the ‘+’ button on the lower left, and select the same type of certificate that you've just revoked to let Xcode request a new one for you.

Let Xcode request a new certificate for you in Xcode > Preferences > Accounts > Apple ID > Manage Certificates…

Step 4: Update your provisioning profiles to use the new certificate

After which, head back to Member Center > Certificates, Identifiers & Profiles > Provisioning Profiles > All. You'll notice that any provisioning profile that made use of the revoked certificate is now reflected as ‘Invalid’.

Notice that any provisioning profile that made use of the revoked certificate is now reflected as ‘Invalid’

Click on any profile that are now ‘Invalid’, click ‘Edit’, then choose the newly created certificate, then click on ‘Generate’. Repeat this until all provisioning profiles are regenerated with the new certificate.

Choose the newly created certificate, and click on Generate

Step 5: Use Xcode to download the new provisioning profiles

Tip: Before you download the new profiles using Xcode, you may want to clear any existing and possibly invalid provisioning profiles from your Mac. You can do so by removing all the profiles from ~/Library/MobileDevice/Provisioning Profiles

Back in Xcode > Preferences > Accounts > [Apple ID], click on the ‘Download All Profiles’ button to ask Xcode to download all the provisioning profiles from your developer account.

Click Download All Profiles for Xcode to download all the newly generated profiles

How can I retrieve the remote git address of a repo?

If you have the name of the remote, you will be able with git 2.7 (Q4 2015), to use the new git remote get-url command:

git remote get-url origin

(nice pendant of git remote set-url origin <newurl>)

See commit 96f78d3 (16 Sep 2015) by Ben Boeckel (mathstuf).
(Merged by Junio C Hamano -- gitster -- in commit e437cbd, 05 Oct 2015)

remote: add get-url subcommand

Expanding insteadOf is a part of ls-remote --url and there is no way to expand pushInsteadOf as well.
Add a get-url subcommand to be able to query both as well as a way to get all configured urls.

Why was the name 'let' chosen for block-scoped variable declarations in JavaScript?

It does exactly what the var does with a scope difference. Now it can not take the name var since that is already taken.

So it looks that it has taken the next best name which has a semantic in an interesting English language construct.

let myPet = 'dog';

In English it says "Let my pet be a dog"

How do I get the SharedPreferences from a PreferenceActivity in Android?

Try following source code it worked for me

//Fetching id from shared preferences
    SharedPreferences sharedPreferences;
    sharedPreferences =getSharedPreferences(Constant.SHARED_PREF_NAME, Context.MODE_PRIVATE);
    getUserLogin = sharedPreferences.getString(Constant.ID_SHARED_PREF, "");

Equivalent of typedef in C#

You can use an open source library and NuGet package called LikeType that I created that will give you the GenericClass<int> behavior that you're looking for.

The code would look like:

public class SomeInt : LikeType<int>
    public SomeInt(int value) : base(value) { }

public class HashSetExample
    public void Contains_WhenInstanceAdded_ReturnsTrueWhenTestedWithDifferentInstanceHavingSameValue()
        var myInt = new SomeInt(42);
        var myIntCopy = new SomeInt(42);
        var otherInt = new SomeInt(4111);

        Assert.IsTrue(myInt == myIntCopy);

        var mySet = new HashSet<SomeInt>();


TypeError: not all arguments converted during string formatting python

In my case, it's because I need only a single %s, i missing values input.

PostgreSQL: Why psql can't connect to server?

During fresh installation of postgresql. By default, user name and password is assigned as "postgres". The feature this RDBMS provides is to add role for new user and create database. If you are getting such errors:

  1. login in by default username:

    root@kalilinux:~# sudo -i -u postgres

  2. ype psql for interactive prompt

    postgres@kalilinux:~$ psql

  3. To quit from prompt use


  4. To create new user role

    postgres@kalilinux:~$ createuser --interactive

Now you are in interacive psql shell. Enjoy. Dont forget to login in from your username and type psql for shell.

Convert MySQL to SQlite

If you have experience write simple scripts by Perl\Python\etc, and convert MySQL to SQLite. Read data from Mysql and write it on SQLite.

How to downgrade to older version of Gradle

Got to

Change the version of the below mentioned distribution (