Programs & Examples On #Ixmldomdocument

How to find sitemap.xml path on websites?

There is no standard, so there is no guarantee. With that said, its common for the sitemap to be self labeled and on the root, like this:

Case is sensitive on some servers, so keep that in mind. If its not there, look in the robots file on the root:

If you don't see it listed in the robots file head to Google and search this: filetype:xml

This will limit the results to XML files on your target domain. At this point its trial-and-error and based on the specifics of the website you are working with. If you get several pages of results from the Google search phrase above then try to limit the results further:

filetype:xml inurl:sitemap


filetype:xml inurl:products

If you still can't find it you can right-click > "View Source" and do a search (aka: "control find" or Ctrl + F) for .xml to see if there is a reference to it in the code.

MongoDB not equal to

Use $ne -- $not should be followed by the standard operator:

An examples for $ne, which stands for not equal:

use test
switched to db test
db.test.insert({author : 'me', post: ""})
db.test.insert({author : 'you', post: "how to query"})
db.test.find({'post': {$ne : ""}})
{ "_id" : ObjectId("4f68b1a7768972d396fe2268"), "author" : "you", "post" : "how to query" }

And now $not, which takes in predicate ($ne) and negates it ($not):

db.test.find({'post': {$not: {$ne : ""}}})
{ "_id" : ObjectId("4f68b19c768972d396fe2267"), "author" : "me", "post" : "" }

org.hibernate.MappingException: Unknown entity: annotations.Users

I was facing the same issue and I searched for almost 2 hours and tried with different possible ways like replacing old hibernate JARs and changing the DB table schema. But finally got the solution as below:

SessionFactory factory = new Configuration().configure().buildSessionFactory(); //This line to be replaced with below commented line

Replace above for

//Configuration config = new Configuration().configure();
//ServiceRegistry servReg = new StandardServiceRegistryBuilder().applySettings(config.getProperties()).build();
//SessionFactory factory = config.buildSessionFactory(servReg);

It will then work fine..

How do I extract data from JSON with PHP?

Consider using JSONPath

There is a pretty clear explanation of how to use it and parse a JSON-file avoiding all the loops proposed. If you are familiar with XPath for XML you will start loving this approach.

Convert timestamp to date in MySQL query

Convert timestamp to date in MYSQL

Make the table with an integer timestamp:

mysql> create table foo(id INT, mytimestamp INT(11));
Query OK, 0 rows affected (0.02 sec)

Insert some values

mysql> insert into foo values(1, 1381262848);
Query OK, 1 row affected (0.01 sec)

Take a look

mysql> select * from foo;
| id   | mytimestamp |
|    1 |  1381262848 |
1 row in set (0.00 sec)

Convert the number to a timestamp:

mysql> select id, from_unixtime(mytimestamp) from foo;
| id   | from_unixtime(mytimestamp) |
|    1 | 2013-10-08 16:07:28        |
1 row in set (0.00 sec)

Convert it into a readable format:

mysql> select id, from_unixtime(mytimestamp, '%Y %D %M %H:%i:%s') from foo;
| id   | from_unixtime(mytimestamp, '%Y %D %M %H:%i:%s') |
|    1 | 2013 8th October 04:07:28                       |
1 row in set (0.00 sec)

Set time to 00:00:00

One more JAVA 8 way:

LocalDateTime localDateTime =;

But it's a lot more useful to edit the date that already exists.

UIButton: set image for selected-highlighted state

Correct me if I am wrong. By doing

   [button setSelected:YES];

you are clearly changing the state of the buttons as selected. So naturally by the code you have provided the image will that for the selected state in your case checked.png

Converting Long to Date in Java returns 1970

The Date constructor (click the link!) accepts the time as long in milliseconds, not seconds. You need to multiply it by 1000 and make sure that you supply it as long.

Date d = new Date(1220227200L * 1000);

This shows here

Sun Aug 31 20:00:00 GMT-04:00 2008

There is no ViewData item of type 'IEnumerable<SelectListItem>' that has the key 'xxx'

In my case there was a conflict in the namespaces , I have:

using System.Web.Mvc;


using System.Collections.Generic;

I explicitly want to use the Mvc one so I declared it as :

new System.Web.Mvc.SelectList(...)

"Sources directory is already netbeans project" error when opening a project from existing sources

If this is your own source code and you already have a Netbeans project folder with your source files you should just start with:

File | Open Project... 


File | New Project ... 

because the project is not new.

Circle button css

An round button with box-shadow

.btn {
  height: 50px;
  width: 50px;
  line-height: 50px;
  font-size: 2em;
  border-radius: 50%;
  background-color: red;
  color: white;
  text-align: center;
  border: none;
  cursor: pointer;
  position: fixed;
  z-index: 1;
  bottom: 10%;
  right: 4%;
  box-shadow: 0 3px 5px -1px rgba(0, 0, 0, 0.2), 0 6px 10px 0 rgba(0, 0, 0, 0.14), 0 1px 18px 0 rgba(0, 0, 0, 0.12);
<div class="btn">+</div>

Command to collapse all sections of code?

if you want to collapse and expand particular loop, if else then install following plugins for visual studio.

enter image description here

How to Avoid Response.End() "Thread was being aborted" Exception during the Excel file download

I removed the linkbutton from the UpdatePanel and also commented the Response.End() Success!!!

Where is nodejs log file?

For nodejs log file you can use winston and morgan and in place of your console.log() statement user winston.log() or other winston methods to log. For working with winston and morgan you need to install them using npm. Example: npm i -S winston npm i -S morgan

Then create a folder in your project with name winston and then create a config.js in that folder and copy this code given below.

const appRoot = require('app-root-path');
const winston = require('winston');

// define the custom settings for each transport (file, console)
const options = {
  file: {
    level: 'info',
    filename: `${appRoot}/logs/app.log`,
    handleExceptions: true,
    json: true,
    maxsize: 5242880, // 5MB
    maxFiles: 5,
    colorize: false,
  console: {
    level: 'debug',
    handleExceptions: true,
    json: false,
    colorize: true,

// instantiate a new Winston Logger with the settings defined above
let logger;
if (process.env.logging === 'off') {
  logger = winston.createLogger({
    transports: [
      new winston.transports.File(options.file),
    exitOnError: false, // do not exit on handled exceptions
} else {
  logger = winston.createLogger({
    transports: [
      new winston.transports.File(options.file),
      new winston.transports.Console(options.console),
    exitOnError: false, // do not exit on handled exceptions

// create a stream object with a 'write' function that will be used by `morgan` = {
  write(message) {;

module.exports = logger;

After copying the above code make make a folder with name logs parallel to winston or wherever you want and create a file app.log in that logs folder. Go back to config.js and set the path in the 5th line "filename: ${appRoot}/logs/app.log, " to the respective app.log created by you.

After this go to your index.js and include the following code in it.

const morgan = require('morgan');
const winston = require('./winston/config');
const express = require('express');
const app = express();
app.use(morgan('combined', { stream: }));'You have successfully started working with winston and morgan');

How to achieve ripple animation using support library?

I made a simple class that makes ripple buttons, i never needed it in the end so its not the best, But here it is:

import android.content.Context;
import android.os.Handler;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.widget.Button;

public class RippleView extends Button
    private float duration = 250;

    private float speed = 1;
    private float radius = 0;
    private Paint paint = new Paint();
    private float endRadius = 0;
    private float rippleX = 0;
    private float rippleY = 0;
    private int width = 0;
    private int height = 0;
    private OnClickListener clickListener = null;
    private Handler handler;
    private int touchAction;
    private RippleView thisRippleView = this;

    public RippleView(Context context)
        this(context, null, 0);

    public RippleView(Context context, AttributeSet attrs)
        this(context, attrs, 0);

    public RippleView(Context context, AttributeSet attrs, int defStyleAttr)
        super(context, attrs, defStyleAttr);

    private void init()
        if (isInEditMode())

        handler = new Handler();

    protected void onSizeChanged(int w, int h, int oldw, int oldh)
        super.onSizeChanged(w, h, oldw, oldh);
        width = w;
        height = h;

    protected void onDraw(@NonNull Canvas canvas)

        if(radius > 0 && radius < endRadius)
            canvas.drawCircle(rippleX, rippleY, radius, paint);
            if(touchAction == MotionEvent.ACTION_UP)

    public boolean onTouchEvent(@NonNull MotionEvent event)
        rippleX = event.getX();
        rippleY = event.getY();

            case MotionEvent.ACTION_UP:
                touchAction = MotionEvent.ACTION_UP;

                radius = 1;
                endRadius = Math.max(Math.max(Math.max(width - rippleX, rippleX), rippleY), height - rippleY);
                speed = endRadius / duration * 10;
                handler.postDelayed(new Runnable()
                    public void run()
                        if(radius < endRadius)
                            radius += speed;
                            paint.setAlpha(90 - (int) (radius / endRadius * 90));
                            handler.postDelayed(this, 1);
                }, 10);
            case MotionEvent.ACTION_CANCEL:
                touchAction = MotionEvent.ACTION_CANCEL;
                radius = 0;
            case MotionEvent.ACTION_DOWN:
                touchAction = MotionEvent.ACTION_UP;
                endRadius = Math.max(Math.max(Math.max(width - rippleX, rippleX), rippleY), height - rippleY);
                radius = endRadius/4;
                return true;
            case MotionEvent.ACTION_MOVE:
                if(rippleX < 0 || rippleX > width || rippleY < 0 || rippleY > height)
                    touchAction = MotionEvent.ACTION_CANCEL;
                    radius = 0;
                    touchAction = MotionEvent.ACTION_MOVE;
                    return true;

        return false;

    public void setOnClickListener(OnClickListener l)
        clickListener = l;


Since many people are looking for something like this i made a class that can make other views have the ripple effect:

import android.content.Context;
import android.os.Handler;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewGroup;
import android.widget.FrameLayout;

public class RippleViewCreator extends FrameLayout
    private float duration = 150;
    private int frameRate = 15;

    private float speed = 1;
    private float radius = 0;
    private Paint paint = new Paint();
    private float endRadius = 0;
    private float rippleX = 0;
    private float rippleY = 0;
    private int width = 0;
    private int height = 0;
    private Handler handler = new Handler();
    private int touchAction;

    public RippleViewCreator(Context context)
        this(context, null, 0);

    public RippleViewCreator(Context context, AttributeSet attrs)
        this(context, attrs, 0);

    public RippleViewCreator(Context context, AttributeSet attrs, int defStyleAttr)
        super(context, attrs, defStyleAttr);

    private void init()
        if (isInEditMode())



    public static void addRippleToView(View v)
        ViewGroup parent = (ViewGroup)v.getParent();
        int index = -1;
        if(parent != null)
            index = parent.indexOfChild(v);
        RippleViewCreator rippleViewCreator = new RippleViewCreator(v.getContext());
        if(index == -1)
            parent.addView(rippleViewCreator, index);

    protected void onSizeChanged(int w, int h, int oldw, int oldh)
        super.onSizeChanged(w, h, oldw, oldh);
        width = w;
        height = h;

    protected void dispatchDraw(@NonNull Canvas canvas)

        if(radius > 0 && radius < endRadius)
            canvas.drawCircle(rippleX, rippleY, radius, paint);
            if(touchAction == MotionEvent.ACTION_UP)

    public boolean onInterceptTouchEvent(MotionEvent event)
        return true;

    public boolean onTouchEvent(@NonNull MotionEvent event)
        rippleX = event.getX();
        rippleY = event.getY();

        touchAction = event.getAction();
            case MotionEvent.ACTION_UP:

                radius = 1;
                endRadius = Math.max(Math.max(Math.max(width - rippleX, rippleX), rippleY), height - rippleY);
                speed = endRadius / duration * frameRate;
                handler.postDelayed(new Runnable()
                    public void run()
                        if(radius < endRadius)
                            radius += speed;
                            paint.setAlpha(90 - (int) (radius / endRadius * 90));
                            handler.postDelayed(this, frameRate);
                        else if(getChildAt(0) != null)
                }, frameRate);
            case MotionEvent.ACTION_CANCEL:
            case MotionEvent.ACTION_DOWN:
                endRadius = Math.max(Math.max(Math.max(width - rippleX, rippleX), rippleY), height - rippleY);
                radius = endRadius/3;
                return true;
            case MotionEvent.ACTION_MOVE:
                if(rippleX < 0 || rippleX > width || rippleY < 0 || rippleY > height)
                    touchAction = MotionEvent.ACTION_CANCEL;
                    return true;
        return false;

    public final void addView(@NonNull View child, int index, ViewGroup.LayoutParams params)
        //limit one view
        if (getChildCount() > 0)
            throw new IllegalStateException(this.getClass().toString()+" can only have one child.");
        super.addView(child, index, params);

How do I use a 32-bit ODBC driver on 64-bit Server 2008 when the installer doesn't create a standard DSN?

Open IIS manager, select Application Pools, select the application pool you are using, click on Advanced Settings in the right-hand menu. Under General, set "Enable 32-Bit Applications" to "True".

What is the right way to check for a null string in Objective-C?

If you want to test against all nil/empty objects (like empty strings or empty arrays/sets) you can use the following:

static inline BOOL IsEmpty(id object) {
    return object == nil
        || ([object respondsToSelector:@selector(length)]
        && [(NSData *) object length] == 0)
        || ([object respondsToSelector:@selector(count)]
        && [(NSArray *) object count] == 0);

In Objective-C, how do I test the object type?

Simple, [yourobject class] it will return the class name of yourobject.

How to run a script at a certain time on Linux?

Cron is good for something that will run periodically, like every Saturday at 4am. There's also anacron, which works around power shutdowns, sleeps, and whatnot. As well as at.

But for a one-off solution, that doesn't require root or anything, you can just use date to compute the seconds-since-epoch of the target time as well as the present time, then use expr to find the difference, and sleep that many seconds.

How can I find script's directory?

import os,sys
# Store current working directory
pwd = os.path.dirname(__file__)
# Append current directory to the python path

How can I search sub-folders using glob.glob module?

If you can install glob2 package...

import glob2
filenames = glob2.glob("C:\\top_directory\\**\\*.ext")  # Where ext is a specific file extension
folders = glob2.glob("C:\\top_directory\\**\\")

All filenames and folders:

all_ff = glob2.glob("C:\\top_directory\\**\\**")  

ImportError: No module named PIL

You will need to install Image and pillow with your python package. Rest assured, the command line will take care of everything for you.


python -m pip install image

How to store a dataframe using Pandas

The easiest way is to pickle it using to_pickle:

df.to_pickle(file_name)  # where to save it, usually as a .pkl

Then you can load it back using:

df = pd.read_pickle(file_name)

Note: before 0.11.1 save and load were the only way to do this (they are now deprecated in favor of to_pickle and read_pickle respectively).

Another popular choice is to use HDF5 (pytables) which offers very fast access times for large datasets:

import pandas as pd
store = pd.HDFStore('store.h5')

store['df'] = df  # save it
store['df']  # load it

More advanced strategies are discussed in the cookbook.

Since 0.13 there's also msgpack which may be be better for interoperability, as a faster alternative to JSON, or if you have python object/text-heavy data (see this question).

Apache HttpClient 4.0.3 - how do I set cookie with sessionID for POST request?

You should probably set all of the cookie properties not just the value of it. setPath(), setDomain() ... etc

Why do we use $rootScope.$broadcast in AngularJS?

  1. What does $rootScope.$broadcast do?

    $rootScope.$broadcast is sending an event through the application scope. Any children scope of that app can catch it using a simple: $scope.$on().

    It is especially useful to send events when you want to reach a scope that is not a direct parent (A branch of a parent for example)

    !!! One thing to not do however is to use $rootScope.$on from a controller. $rootScope is the application, when your controller is destroyed that event listener will still exist, and when your controller will be created again, it will just pile up more event listeners. (So one broadcast will be caught multiple times). Use $scope.$on() instead, and the listeners will also get destroyed.

  2. What is the difference between $rootScope.$broadcast & $rootScope.$broadcast.apply?

    Sometimes you have to use apply(), especially when working with directives and other JS libraries. However since I don't know that code base, I wouldn't be able to tell if that's the case here.

in a "using" block is a SqlConnection closed on return or exception?

Dispose simply gets called when you leave the scope of using. The intention of "using" is to give developers a guaranteed way to make sure that resources get disposed.

From MSDN:

A using statement can be exited either when the end of the using statement is reached or if an exception is thrown and control leaves the statement block before the end of the statement.

Which font is used in Visual Studio Code Editor and how to change fonts?

Go to Preferences > User Settings. (Alternatively, Ctrl + , / Cmd + , on macOS)

Then you can type inside the JSON object any settings you want to override. User settings are per user. You can also configure workspace settings, which are for the project that you are currently working on.

Here's an example:

// Controls the font family.
"editor.fontFamily": "Consolas",

// Controls the font size.
"editor.fontSize": 13

Useful links:

Best approach to remove time part of datetime in SQL Server

How about select cast(cast my_datetime_field as date) as datetime)? This results in the same date, with the time set to 00:00, but avoids any conversion to text and also avoids any explicit numeric rounding.

Update int column in table with unique incrementing values

DECLARE @IncrementValue int
SET @IncrementValue = 0 
UPDATE Samples SET qty = @IncrementValue,@IncrementValue=@IncrementValue+1

Regex to Match Symbols: !$%^&*()_+|~-=`{}[]:";'<>?,./

Replace all latters from any language in 'A', and if you wish for example all digits to 0:

return str.replace(/[^\s!-@[-`{-~]/g, "A").replace(/\d/g, "0");

How to change plot background color?

Something like this? Use the axisbg keyword to subplot:

>>> from matplotlib.figure import Figure
>>> from matplotlib.backends.backend_agg import FigureCanvasAgg as FigureCanvas
>>> figure = Figure()
>>> canvas = FigureCanvas(figure)
>>> axes = figure.add_subplot(1, 1, 1, axisbg='red')
>>> axes.plot([1,2,3])
[<matplotlib.lines.Line2D object at 0x2827e50>]
>>> canvas.print_figure('red-bg.png')

(Granted, not a scatter plot, and not a black background.)

enter image description here

How do you make an array of structs in C?

Solution using pointers:

#define n 3
struct body
    double p[3];//position
    double v[3];//velocity
    double a[3];//acceleration
    double radius;
    double *mass;

int main()
    struct body *bodies = (struct body*)malloc(n*sizeof(struct body));
    int a, b;
     for(a = 0; a < n; a++)
            for(b = 0; b < 3; b++)
                bodies[a].p[b] = 0;
                bodies[a].v[b] = 0;
                bodies[a].a[b] = 0;
            bodies[a].mass = 0;
            bodies[a].radius = 1.0;

    return 0;

What's the difference between a POST and a PUT HTTP REQUEST?

Actually there's no difference other than their title. There's actually a basic difference between GET and the others. With a "GET"-Request method, you send the data in the url-address-line, which are separated first by a question-mark, and then with a & sign.

But with a "POST"-request method, you can't pass data through the url, but you have to pass the data as an object in the so called "body" of the request. On the server side, you have then to read out the body of the received content in order to get the sent data. But there's on the other side no possibility to send content in the body, when you send a "GET"-Request.

The claim, that "GET" is only for getting data and "POST" is for posting data, is absolutely wrong. Noone can prevent you from creating new content, deleting existing content, editing existing content or do whatever in the backend, based on the data, that is sent by the "GET" request or by the "POST" request. And nobody can prevent you to code the backend in a way, that with a "POST"-Request, the client asks for some data.

With a request, no matter which method you use, you call a URL and send or don't send some data to specify, which information you want to pass to the server to deal with your request, and then the client gets an answer from the server. The data can contain whatever you want to send, the backend is allowed to do whatever it wants with the data and the response can contain any information, that you want to put in there.

There are only these two BASIC METHODS. GET and POST. But it's their structure, which makes them different and not what you code in the backend. In the backend you can code whatever you want to, with the received data. But with the "POST"-request you have to send/retrieve the data in the body and not in the url-addressline, and with a "GET" request, you have to send/retrieve data in the url-addressline and not in the body. That's all.

All the other methods, like "PUT", "DELETE" and so on, they have the same structure as "POST".

The POST Method is mainly used, if you want to hide the content somewhat, because whatever you write in the url-addressline, this will be saved in the cache and a GET-Method is the same as writing a url-addressline with data. So if you want to send sensitive data, which is not always necessarily username and password, but for example some ids or hashes, which you don't want to be shown in the url-address-line, then you should use the POST method.

Also the URL-Addressline's length is limited to 1024 symbols, whereas the "POST"-Method is not restricted. So if you have a bigger amount of data, you might not be able to send it with a GET-Request, but you'll need to use the POST-Request. So this is also another plus point for the POST-request.

But dealing with the GET-request is way easier, when you don't have complicated text to send. Otherwise, and this is another plus point for the POST method, is, that with the GET-method you need to url-encode the text, in order to be able to send some symbols within the text or even spaces. But with a POST method you have no restrictions and your content doesn't need to be changed or manipulated in any way.

How to start an application without waiting in a batch file?

I'm making a guess here, but your start invocation probably looks like this:

start "\Foo\Bar\Path with spaces in it\program.exe"

This will open a new console window, using “\Foo\Bar\Path with spaces in it\program.exe” as its title.

If you use start with something that is (or needs to be) surrounded by quotes, you need to put empty quotes as the first argument:

start "" "\Foo\Bar\Path with spaces in it\program.exe"

This is because start interprets the first quoted argument it finds as the window title for a new console window.

Failed to load resource: the server responded with a status of 404 (Not Found) error in server

Use your browser's network inspector (F12) to see when the browser is requesting the bgbody.png image and what absolute path it's using and why the server is returning a 404 response.

...assuming that bgbody.png actually exists :)

Is your CSS in a stylesheet file or in a <style> block in a page? If it's in a stylesheet then the relative path must be relative to the CSS stylesheet (not the document that references it). If it's in a page then it must be relative to the current resource path. If you're using non-filesystem-based resource paths (i.e. using URL rewriting or URL routing) then this will cause problems and it's best to always use absolute paths.

Going by your relative path it looks like you store your images separately from your stylesheets. I don't think this is a good idea - I support storing images and other resources, like fonts, in the same directory as the stylesheet itself, as it simplifies paths and is also a more logical filesystem arrangement.

Converting an int to std::string

Well the well known way to do that is using the stream operator :

#include <sstream>

std::ostringstream s;
int i;

s << i;

std::string converted(s.str());

Of course you can generalize it for any type using a template function ^^

#include <sstream>

template<typename T>
std::string toString(const T& value)
    std::ostringstream oss;
    oss << value;
    return oss.str();

What's the best way to parse a JSON response from the requests library?

You can use json.loads:

import json
import requests

response = requests.get(...)
json_data = json.loads(response.text)

This converts a given string into a dictionary which allows you to access your JSON data easily within your code.

Or you can use @Martijn's helpful suggestion, and the higher voted answer, response.json().

How to add http:// if it doesn't exist in the URL

Simply check if there is a protocol (delineated by "://") and add "http://" if there isn't.

if (false === strpos($url, '://')) {
    $url = 'http://' . $url;

Note: This may be a simple and straightforward solution, but Jack's answer using parse_url is almost as simple and much more robust. You should probably use that one.

How do I get the result of a command in a variable in windows?

To get the current directory, you can use this:

CD > tmpFile
SET /p myvar= < tmpFile
DEL tmpFile
echo test: %myvar%

It's using a temp-file though, so it's not the most pretty, but it certainly works! 'CD' puts the current directory in 'tmpFile', 'SET' loads the content of tmpFile.

Here is a solution for multiple lines with "array's":

@echo off

rem ---------
rem Obtain line numbers from the file
rem ---------

rem This is the file that is being read: You can replace this with %1 for dynamic behaviour or replace it with some command like the first example i gave with the 'CD' command.
set _readfile=test.txt

for /f "usebackq tokens=2 delims=:" %%a in (`find /c /v "" %_readfile%`) do set _max=%%a
set /a _max+=1
set _i=0
set _filename=temp.dat

rem ---------
rem Make the list
rem ---------

find /n /v "" %_readfile% >%_filename%

rem ---------
rem Read the list
rem ---------

if %_i%==%_max% goto printList

rem ---------
rem Read the lines into the array
rem ---------
for /f "usebackq delims=] tokens=2" %%a in (`findstr /r "\[%_i%]" %_filename%`) do set _data%_i%=%%a
set /a _i+=1
goto readList

del %_filename%
set _i=1
if %_i%==%_max% goto finished
set _data%_i%
set /a _i+=1
goto printMore


But you might want to consider moving to another more powerful shell or create an application for this stuff. It's stretching the possibilities of the batch files quite a bit.

How to compare DateTime in C#?

If you have two DateTime that looks the same, but Compare or Equals doesn't return what you expect, this is how to compare them.

Here an example with 1-millisecond precision:

bool areSame = (date1 - date2) > TimeSpan.FromMilliseconds(1d);

How to change Android usb connect mode to charge only?

I have been searching for this for ages on my CM 11 android phone, running kitkat.

Well.. finally I found it. It's hidden in a totally unintuitive location:

  1. Go to settings
  2. Go to storage
  3. Open the menu and choose USB computer connection

Here you can choose between Media Device (MTP), Camera (PTP) and Mass storage (UMS). Turn them all off to get it to charge only.

Sadly, if the option is not there, it is not supported by the phone. This seems to be the case for my HTC One (M7).

How do I read configuration settings from Symfony2 config.yml?

While the solution of moving the contact_email to parameters.yml is easy, as proposed in other answers, that can easily clutter your parameters file if you deal with many bundles or if you deal with nested blocks of configuration.

  • First, I'll answer strictly the question.
  • Later, I'll give an approach for getting those configs from services without ever passing via a common space as parameters.

FIRST APPROACH: Separated config block, getting it as a parameter

With an extension (more on extensions here) you can keep this easily "separated" into different blocks in the config.yml and then inject that as a parameter gettable from the controller.

Inside your Extension class inside the DependencyInjection directory write this:

class MyNiceProjectExtension extends Extension
    public function load( array $configs, ContainerBuilder $container )
        // The next 2 lines are pretty common to all Extension templates.
        $configuration = new Configuration();
        $processedConfig = $this->processConfiguration( $configuration, $configs );

        // This is the KEY TO YOUR ANSWER
        $container->setParameter( 'my_nice_project.contact_email', $processedConfig[ 'contact_email' ] );

        // Other stuff like loading services.yml

Then in your config.yml, config_dev.yml and so you can set

    contact_email: [email protected]

To be able to process that config.yml inside your MyNiceBundleExtension you'll also need a Configuration class in the same namespace:

class Configuration implements ConfigurationInterface
    public function getConfigTreeBuilder()
        $treeBuilder = new TreeBuilder();
        $rootNode = $treeBuilder->root( 'my_nice_project' );

        $rootNode->children()->scalarNode( 'contact_email' )->end();

        return $treeBuilder;

Then you can get the config from your controller, as you desired in your original question, but keeping the parameters.yml clean, and setting it in the config.yml in separated sections:

$recipient = $this->container->getParameter( 'my_nice_project.contact_email' );

SECOND APPROACH: Separated config block, injecting the config into a service

For readers looking for something similar but for getting the config from a service, there is even a nicer way that never clutters the "paramaters" common space and does even not need the container to be passed to the service (passing the whole container is practice to avoid).

This trick above still "injects" into the parameters space your config.

Nevertheless, after loading your definition of the service, you could add a method-call like for example setConfig() that injects that block only to the service.

For example, in the Extension class:

class MyNiceProjectExtension extends Extension
    public function load( array $configs, ContainerBuilder $container )
        $configuration = new Configuration();
        $processedConfig = $this->processConfiguration( $configuration, $configs );

        // Do not add a paramater now, just continue reading the services.
        $loader = new YamlFileLoader( $container, new FileLocator( __DIR__ . '/../Resources/config' ) );
        $loader->load( 'services.yml' );

        // Once the services definition are read, get your service and add a method call to setConfig()
        $sillyServiceDefintion = $container->getDefinition( 'my.niceproject.sillymanager' );
        $sillyServiceDefintion->addMethodCall( 'setConfig', array( $processedConfig[ 'contact_email' ] ) );

Then in your services.yml you define your service as usual, without any absolute change:

        class: My\NiceProjectBundle\Model\SillyManager
        arguments: []

And then in your SillyManager class, just add the method:

class SillyManager
    private $contact_email;

    public function setConfig( $newConfigContactEmail )
        $this->contact_email = $newConfigContactEmail;

Note that this also works for arrays instead of scalar values! Imagine that you configure a rabbit queue and need host, user and password:

        user: guest
        password: guest

Of course you need to change your Tree, but then you can do:

$sillyServiceDefintion->addMethodCall( 'setConfig', array( $processedConfig[ 'amqp' ] ) );

and then in the service do:

class SillyManager
    private $host;
    private $user;
    private $password;

    public function setConfig( $config )
        $this->host = $config[ 'host' ];
        $this->user = $config[ 'user' ];
        $this->password = $config[ 'password' ];

Hope this helps!

How do I fetch only one branch of a remote Git repository?

If you want to change the default for "git pull" and "git fetch" to only fetch specific branches then you can edit .git/config so that the remote config looks like:

[remote "origin"]
  fetch = +refs/heads/master:refs/remotes/origin/master

This will only fetch master from origin by default. See for more info:

EDIT: Just realized this is the same thing that the -t option does for git remote add. At least this is a nice way to do it after the remote is added if you don't want ot delete the remote and add it again using -t.

jQuery: how to get which button was clicked upon form submission?

You want to use like this:

function clickTheButton() {

var Sender = window.event.srcElement;
alert("the item clicked was " +


for a button that looks like:

<input type="button" id="myButton" onclick="clickTheButton();" value="Click Me"/>

you will get an alert that reads: "the item clicked was myButton.

In your improved example you can add window.event.srcElement to process_form_submission and you will have a reference to whichever element invoked the process.

Microsoft Azure: How to create sub directory in a blob container

If you use Microsoft Azure Storage Explorer, there is a "New Folder" button that allows you to create a folder in a container. This is actually a virtual folder:

enter image description here

Where can I download english dictionary database in a text format?

The Gutenberg Project hosts Webster's Unabridged English Dictionary plus many other public domain literary works. Actually it looks like they've got several versions of the dictionary hosted with copyright from different years. The one I linked has a 2009 copyright. You may want to poke around the site and investigate the different versions of Webster's dictionary.

Are global variables bad?

Yes, because if you let incompetent programmers use them (read 90% especially scientists) you end up with 600+ global variable spread over 20+ files and a project of 12,000 lines where 80% of the functions take void, return void, and operate entirely on global state.

It quickly becomes impossible to understand what is going on at any one point unless you know the entire project.

ng-repeat: access key and value for each object in array of objects

A repeater inside a repeater

<div ng-repeat="step in steps">
    <div ng-repeat="(key, value) in step">
        {{key}} : {{value}}

Click event on select option element in chrome

We can achieve this other way despite of directly calling event with <select>.

JS part:


    alert('Selected value: ' + $(this).val());

HTML part:

<select id="sort">
    <option value="1">View All</option>
    <option value="2">Ready for Review</option>
    <option value="3">Registration Date</option>
    <option value="4">Last Modified</option>
    <option value="5">Ranking</option>
    <option value="6">Reviewed</option>

How do I fix the Visual Studio compile error, "mismatch between processor architecture"?

I had similar problem it was caused by MS UNIT Test DLL. My WPF application was compiled as x86 but unit test DLL (referenced EXE file) as "Any CPU". I changed unit test DLL to be compiled for x86 (same as EXE) and it was resovled.

Objective-C: Extract filename from path string

If you're displaying a user-readable file name, you do not want to use lastPathComponent. Instead, pass the full path to NSFileManager's displayNameAtPath: method. This basically does does the same thing, only it correctly localizes the file name and removes the extension based on the user's preferences.

Draw on HTML5 Canvas using a mouse

I think, other examples here are too complicated. This one is simpler and JS only...

// create canvas element and append it to document body_x000D_
var canvas = document.createElement('canvas');_x000D_
// some hotfixes... ( ?_?)_x000D_ = 0;_x000D_ = 'fixed';_x000D_
// get canvas 2D context and set him correct size_x000D_
var ctx = canvas.getContext('2d');_x000D_
// last known position_x000D_
var pos = { x: 0, y: 0 };_x000D_
window.addEventListener('resize', resize);_x000D_
document.addEventListener('mousemove', draw);_x000D_
document.addEventListener('mousedown', setPosition);_x000D_
document.addEventListener('mouseenter', setPosition);_x000D_
// new position from mouse event_x000D_
function setPosition(e) {_x000D_
  pos.x = e.clientX;_x000D_
  pos.y = e.clientY;_x000D_
// resize canvas_x000D_
function resize() {_x000D_
  ctx.canvas.width = window.innerWidth;_x000D_
  ctx.canvas.height = window.innerHeight;_x000D_
function draw(e) {_x000D_
  // mouse left button must be pressed_x000D_
  if (e.buttons !== 1) return;_x000D_
  ctx.beginPath(); // begin_x000D_
  ctx.lineWidth = 5;_x000D_
  ctx.lineCap = 'round';_x000D_
  ctx.strokeStyle = '#c0392b';_x000D_
  ctx.moveTo(pos.x, pos.y); // from_x000D_
  ctx.lineTo(pos.x, pos.y); // to_x000D_
  ctx.stroke(); // draw it!_x000D_

dynamic_cast and static_cast in C++

First, to describe dynamic cast in C terms, we have to represent classes in C. Classes with virtual functions use a "VTABLE" of pointers to the virtual functions. Comments are C++. Feel free to reformat and fix compile errors...

// class A { public: int data; virtual int GetData(){return data;} };
typedef struct A { void**vtable; int data;} A;
int AGetData(A*this){ return this->data; }
void * Avtable[] = { (void*)AGetData };
A * newA() { A*res = malloc(sizeof(A)); res->vtable = Avtable; return res; }

// class B : public class A { public: int moredata; virtual int GetData(){return data+1;} }
typedef struct B { void**vtable; int data; int moredata; } B;
int BGetData(B*this){ return this->data + 1; }
void * Bvtable[] = { (void*)BGetData };
B * newB() { B*res = malloc(sizeof(B)); res->vtable = Bvtable; return res; }

// int temp = ptr->GetData();
int temp = ((int(*)())ptr->vtable[0])();

Then a dynamic cast is something like:

// A * ptr = new B();
A * ptr = (A*) newB();
// B * aB = dynamic_cast<B>(ptr);
B * aB = ( ptr->vtable == Bvtable ? (B*) aB : (B*) 0 );

Passing arguments to JavaScript function from code-behind

    <script type="text/javascript">

        function test(x, y) 
            var cc = "";
            for (var i = 0; i < x.length; i++) 
                cc += x[i]; 
            cc += "\ny: " + y; 
            return cc;




    <form id="form1" runat="server">

        <asp:Button ID="Button1" runat="server" Text="Button"   />

             <asp:TextBox ID="TextBox1"  Name="TextBox1"  runat="server" AutoPostBack="True"  TextMode="MultiLine"></asp:TextBox>


protected void Page_Load(object sender, EventArgs e)
    int[] x = new int[] { 1, 2, 3, 4, 5 };
    int[] y = new int[] { 1, 2, 3, 4, 5 };

    string xStr = getArrayString(x); // converts {1,2,3,4,5} to [1,2,3,4,5]
    string yStr = getArrayString(y);

    string script = String.Format(" var y = test({0},{1}) ; ", xStr, yStr);
    script += String.Format("  document.getElementById(\"TextBox1\").value = y  ");

    this.Page.ClientScript.RegisterStartupScript(this.GetType(),  "testFunction", script, true);
  //  this.Page.ClientScript.RegisterClientScriptBlock(this.GetType(), "testFunction", script, true); // different result

private string getArrayString(int[] array)
    StringBuilder sb = new StringBuilder();
    for (int i = 0; i < array.Length; i++)
        sb.Append(array[i] + ",");
    string arrayStr = string.Format("[{0}]", sb.ToString().TrimEnd(','));
    return arrayStr;

JavaScript string newline character?

Get a line separator for the current browser:

function getLineSeparator() {
  var textarea = document.createElement("textarea");
  textarea.value = "\n"; 
  return textarea.value;

How add items(Text & Value) to ComboBox & read them in SelectedIndexChanged (SelectedValue = null)

You can take the SelectedItem and cast it back to your class and access its properties.


Edit You can try using DataTextField and DataValueField, I used it with DataSource.

ComboBox_Servers.DataTextField = "Text";
ComboBox_Servers.DataValueField = "Value";

In Python, how to check if a string only contains certain characters?

Simpler approach? A little more Pythonic?

>>> ok = "0123456789abcdef"
>>> all(c in ok for c in "123456abc")
>>> all(c in ok for c in "hello world")

It certainly isn't the most efficient, but it's sure readable.

Regular expression for matching latitude/longitude coordinates?

You can try this:

var latExp = /^(?=.)-?((8[0-5]?)|([0-7]?[0-9]))?(?:\.[0-9]{1,20})?$/;
var lngExp = /^(?=.)-?((0?[8-9][0-9])|180|([0-1]?[0-7]?[0-9]))?(?:\.[0-9]{1,20})?$/;

Why are exclamation marks used in Ruby methods?

It is most accurate to say that methods with a Bang! are the more dangerous or surprising version. There are many methods that mutate without a Bang such as .destroy and in general methods only have bangs where a safer alternative exists in the core lib.

For instance, on Array we have .compact and .compact!, both methods mutate the array, but .compact! returns nil instead of self if there are no nil's in the array, which is more surprising than just returning self.

The only non-mutating method I've found with a bang is Kernel's .exit! which is more surprising than .exit because you cannot catch SystemExit while the process is closing.

Rails and ActiveRecord continues this trend in that it uses bang for more 'surprising' effects like .create! which raises errors on failure.

Convert Set to List without creating new List

Map<String, List> mainMap = new HashMap<String, List>();

for(int i=0; i<something.size(); i++){
  Set set = getSet(...); //return different result each time
  mainMap.put(differentKeyName, new ArrayList(set));

Get current date/time in seconds

These JavaScript solutions give you the milliseconds or the seconds since the midnight, January 1st, 1970.

The IE 9+ solution(IE 8 or the older version doesn't support this.):

var timestampInMilliseconds =;
var timestampInSeconds = / 1000; // A float value; not an integer.
    timestampInSeconds = Math.floor( / 1000); // Floor it to get the seconds.
    timestampInSeconds = / 1000 | 0; // Also you can do floor it like this.
    timestampInSeconds = Math.round( / 1000); // Round it to get the seconds.

To get more information about

The generic solution:

// ‘+’ operator makes the operand numeric.
// And ‘new’ operator can be used without the arguments ‘(……)’.
var timestampInMilliseconds = +new Date;
var timestampInSeconds = +new Date / 1000; // A float value; not an intger.
    timestampInSeconds = Math.floor(+new Date / 1000); // Floor it to get the seconds.
    timestampInSeconds = +new Date / 1000 | 0; // Also you can do floor it like this.
    timestampInSeconds = Math.round(+new Date / 1000); // Round it to get the seconds.

Be careful to use, if you don't want something like this case.

if(1000000 < Math.round(1000000.2)) // false.

lodash: mapping array to object

You can use one liner javascript with array reduce method and ES6 destructuring to convert array of key value pairs to object.

arr.reduce((map, { name, input }) => ({, [name]: input }), {});

no module named urllib.parse (How should I install it?)

You want urlparse using python2:

from urlparse import urlparse

How do I get the max and min values from a set of numbers entered?

This is what I did and it works try and play around with it. It calculates total,avarage,minimum and maximum.

public static void main(String[] args) {
   int[] score= {56,90,89,99,59,67};
   double avg;
   int sum=0;
   int maxValue=0;
   int minValue=100;

   for(int i=0;i<6;i++){
System.out.print("Max: "+maxValue+"," +" Min: "+minValue+","+" Avarage: "+avg+","+" Sum: "+sum);}


List Git aliases

for windows:

git config --list | findstr "alias"

How to change value for innodb_buffer_pool_size in MySQL on Mac OS?

As stated,


Following the convention on the other predefined variables, make sure there is no space either side of the equals sign.

Then run

sudo service mysqld stop
sudo service mysqld start


Sometimes, e.g. on Ubuntu, the MySQL daemon is named mysql as opposed to mysqld

I find that running /etc/init.d/mysqld restart doesn't always work and you may get an error like

Stopping mysqld:                                           [FAILED]
Starting mysqld:                                           [  OK  ]

To see if the variable has been set, run show variables and see if the value has been updated.

Efficient thresholding filter of an array with numpy

b = a[a>threshold] this should do

I tested as follows:

import numpy as np, datetime
# array of zeros and ones interleaved
lrg = np.arange(2).reshape((2,-1)).repeat(1000000,-1).flatten()

t0 =
flt = lrg[lrg==0]
print - t0

t0 =
flt = np.array(filter(lambda x:x==0, lrg))
print - t0

I got

$ python

No 'Access-Control-Allow-Origin' header in Angular 2 app

this is server configuration, set up config.addAllowedHeader("*"); in the CorsConfiguration.

Why would I use dirname(__FILE__) in an include or include_once statement?

I might have even a simpler explanation to this question compared to the accepted answer so I'm going to give it a go: Assume this is the structure of the files and directories of a project:

Project root directory:

(dir1 is a directory and file2.php is inside it)

And this is the content of each of the three files above:

<?php include "dir1/file2.php"

<?php include "../file3.php"

<?php echo "Hello, Test!";

Now run file1.php and try to guess what should happen. You might expect to see "Hello, Test!", however, it won't be shown! What you'll get instead will be an error indicating that the file you have requested(file3.php) does not exist!

The reason is that, inside file1.php when you include file2.php, the content of it is getting copied and then pasted back directly into file1.php which is inside the root directory, thus this part "../file3.php" runs from the root directory and thus goes one directory up the root! (and obviously it won't find the file3.php).

Now, what should we do ?!

Relative paths of course have the problem above, so we have to use absolute paths. However, absolute paths have also one problem. If you (for example) copy the root folder (containing your whole project) and paste it in anywhere else on your computer, the paths will be invalid from that point on! And that'll be a REAL MESS!

So we kind of need paths that are both absolute and dynamic(Each file dynamically finds the absolute path of itself wherever we place it)!

The way we do that is by getting help from PHP, and dirname() is the function to go for, which gives the absolute path to the directory in which a file exists in. And each file name could also be easily accessed using the __FILE__ constant. So dirname(__FILE__) would easily give you the absolute (while dynamic!) path to the file we're typing in the above code. Now move your whole project to a new place, or even a new system, and tada! it works!

So now if we turn the project above to this:

<?php include(dirname(__FILE__)."/dir1/file2.php");

<?php include(dirname(__FILE__)."/../file3.php");

<?php echo "Hello, Test!";

if you run it, you'll see the almighty Hello, Test!! (hopefully, if you've not done anything else wrong).

It's also worth mentioning that from PHP5, a nicer way(with regards to readability and preventing eye boilage!) has been provided by PHP as well which is the constant __DIR__ which does exactly the same thing as dirname(__FILE__)!

Hope that helps.

JQUERY: Uncaught Error: Syntax error, unrecognized expression



your solution is passing the double quotes as part of the string.

How do I dynamically set HTML5 data- attributes using react?

You should not wrap JavaScript expressions in quotes.

<option data-img-src={this.props.imageUrl} value="1">{this.props.title}</option>

Take a look at the JavaScript Expressions docs for more info.

Showing all errors and warnings

Straight from the php.ini file:

; Error handling and logging ;

; This directive informs PHP of which errors, warnings and notices you would like
; it to take action for. The recommended way of setting values for this
; directive is through the use of the error level constants and bitwise
; operators. The error level constants are below here for convenience as well as
; some common settings and their meanings.
; By default, PHP is set to take action on all errors, notices and warnings EXCEPT
; those related to E_NOTICE and E_STRICT, which together cover best practices and
; recommended coding standards in PHP. For performance reasons, this is the
; recommend error reporting setting. Your production server shouldn't be wasting
; resources complaining about best practices and coding standards. That's what
; development servers and development settings are for.
; Note: The php.ini-development file has this setting as E_ALL. This
; means it pretty much reports everything which is exactly what you want during
; development and early testing.
; Error Level Constants:
; E_ALL             - All errors and warnings (includes E_STRICT as of PHP 5.4.0)
; E_ERROR           - fatal run-time errors
; E_RECOVERABLE_ERROR  - almost fatal run-time errors
; E_WARNING         - run-time warnings (non-fatal errors)
; E_PARSE           - compile-time parse errors
; E_NOTICE          - run-time notices (these are warnings which often result
;                     from a bug in your code, but it's possible that it was
;                     intentional (e.g., using an uninitialized variable and
;                     relying on the fact it is automatically initialized to an
;                     empty string)
; E_STRICT          - run-time notices, enable to have PHP suggest changes
;                     to your code which will ensure the best interoperability
;                     and forward compatibility of your code
; E_CORE_ERROR      - fatal errors that occur during PHP's initial startup
; E_CORE_WARNING    - warnings (non-fatal errors) that occur during PHP's
;                     initial startup
; E_COMPILE_ERROR   - fatal compile-time errors
; E_COMPILE_WARNING - compile-time warnings (non-fatal errors)
; E_USER_ERROR      - user-generated error message
; E_USER_WARNING    - user-generated warning message
; E_USER_NOTICE     - user-generated notice message
; E_DEPRECATED      - warn about code that will not work in future versions
;                     of PHP
; E_USER_DEPRECATED - user-generated deprecation warnings
; Common Values:
;   E_ALL (Show all errors, warnings and notices including coding standards.)
;   E_ALL & ~E_NOTICE  (Show all errors, except for notices)
;   E_ALL & ~E_NOTICE & ~E_STRICT  (Show all errors, except for notices and coding standards warnings.)
; Default Value: E_ALL & ~E_NOTICE & ~E_STRICT & ~E_DEPRECATED
; Development Value: E_ALL
; Production Value: E_ALL & ~E_DEPRECATED & ~E_STRICT
error_reporting = E_ALL & ~E_DEPRECATED & ~E_STRICT

For pure development I go for:

error_reporting = E_ALL ^ E_NOTICE ^ E_WARNING

Also don't forget to put display_errors to on

display_errors = On

After that, restart your server for Apache on Ubuntu:

sudo /etc/init.d/apache2 restart

php function mail() isn't working

I think you are not configured properly,

if you are using XAMPP then you can easily send mail from localhost.

for example you can configure C:\xampp\php\php.ini and c:\xampp\sendmail\sendmail.ini for gmail to send mail.

in C:\xampp\php\php.ini find extension=php_openssl.dll and remove the semicolon from the beginning of that line to make SSL working for gmail for localhost.

in php.ini file find [mail function] and change
sendmail_from = [email protected]
sendmail_path = "C:\xampp\sendmail\sendmail.exe -t"

(use the above send mail path only and it will work)

Now Open C:\xampp\sendmail\sendmail.ini. Replace all the existing code in sendmail.ini with following code

[email protected]
[email protected]

Now you have done!! create php file with mail function and send mail from localhost.


First, make sure you PHP installation has SSL support (look for an "openssl" section in the output from phpinfo()).

You can set the following settings in your PHP.ini:


How to select the first, second, or third element with a given class name?

use nth-child(item number) EX

<div class="parent_class">
    <div class="myclass">my text1</div>
    some other code+containers...

    <div class="myclass">my text2</div>
    some other code+containers...

    <div class="myclass">my text3</div>
    some other code+containers...
.parent_class:nth-child(1) { };
.parent_class:nth-child(2) { };
.parent_class:nth-child(3) { };


:nth-of-type(item number) same your code

.myclass:nth-of-type(1) { };
.myclass:nth-of-type(2) { };
.myclass:nth-of-type(3) { };

Android Studio - Failed to notify project evaluation listener error

I had buildToolsVersion "27.0.1", upgrading it to 27.0.2 fixed the issue.

Also, my android support deps were at version 27.0.2 so they were not aligned to the buildToolsVersion

Add swipe to delete UITableViewCell

swift 3

func tableView(_ tableView: UITableView, canEditRowAt indexPath: IndexPath) -> Bool {

    return true

func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCellEditingStyle, forRowAt indexPath: IndexPath) {

    if (editingStyle == UITableViewCellEditingStyle.delete) {

        arrayCityName.remove(at: indexPath.row)

How do I clone a single branch in Git?

Can be done in 2 steps

  1. Clone the repository

    git clone <http url>
  2. Checkout the branch you want

    git checkout $BranchName

C++ String Concatenation operator<<

nametext is an std::string but these do not have the stream insertion operator (<<) like output streams do.

To concatenate strings you can use the append member function (or its equivalent, +=, which works in the exact same way) or the + operator, which creates a new string as a result of concatenating the previous two.

pandas python how to count the number of records or rows in a dataframe

Simply, row_num = df.shape[0] # gives number of rows, here's the example:

import pandas as pd
import numpy as np

In [322]: df = pd.DataFrame(np.random.randn(5,2), columns=["col_1", "col_2"])

In [323]: df
      col_1     col_2
0 -0.894268  1.309041
1 -0.120667 -0.241292
2  0.076168 -1.071099
3  1.387217  0.622877
4 -0.488452  0.317882

In [324]: df.shape
Out[324]: (5, 2)

In [325]: df.shape[0]   ## Gives no. of rows/records
Out[325]: 5

In [326]: df.shape[1]   ## Gives no. of columns
Out[326]: 2

Html table tr inside td

Try this code

<table border="1" width="100%">
    <td>Name 1</td>
    <td>Name 2</td>
    <td colspan="2">Name 3</td>
    <td>Name 4</td>

    <td rowspan="3">ITEM 1</td>
    <td rowspan="3">ITEM 2</td>
    <td rowspan="3">ITEM 4</td>

Declaration of Methods should be Compatible with Parent Methods in PHP

This message means that there are certain possible method calls which may fail at run-time. Suppose you have

class A { public function foo($a = 1) {;}}
class B extends A { public function foo($a) {;}}
function bar(A $a) {$a->foo();}

The compiler only checks the call $a->foo() against the requirements of A::foo() which requires no parameters. $a may however be an object of class B which requires a parameter and so the call would fail at runtime.

This however can never fail and does not trigger the error

class A { public function foo($a) {;}}
class B extends A { public function foo($a = 1) {;}}
function bar(A $a) {$a->foo();}

So no method may have more required parameters than its parent method.

The same message is also generated when type hints do not match, but in this case PHP is even more restrictive. This gives an error:

class A { public function foo(StdClass $a) {;}}
class B extends A { public function foo($a) {;}}

as does this:

class A { public function foo($a) {;}}
class B extends A { public function foo(StdClass $a) {;}}

That seems more restrictive than it needs to be and I assume is due to internals.

Visibility differences cause a different error, but for the same basic reason. No method can be less visible than its parent method.

Calling C/C++ from Python?

pybind11 minimal runnable example

pybind11 was previously mentioned at but I would like to give here a concrete usage example and some further discussion about implementation.

All and all, I highly recommend pybind11 because it is really easy to use: you just include a header and then pybind11 uses template magic to inspect the C++ class you want to expose to Python and does that transparently.

The downside of this template magic is that it slows down compilation immediately adding a few seconds to any file that uses pybind11, see for example the investigation done on this issue. PyTorch agrees. A proposal to remediate this problem has been made at:

Here is a minimal runnable example to give you a feel of how awesome pybind11 is:


#include <string>

#include <pybind11/pybind11.h>

struct ClassTest {
    ClassTest(const std::string &name) : name(name) { }
    void setName(const std::string &name_) { name = name_; }
    const std::string &getName() const { return name; }
    std::string name;

namespace py = pybind11;

PYBIND11_PLUGIN(class_test) {
    py::module m("my_module", "pybind11 example plugin");
    py::class_<ClassTest>(m, "ClassTest")
        .def(py::init<const std::string &>())
        .def("setName", &ClassTest::setName)
        .def("getName", &ClassTest::getName)
        .def_readwrite("name", &ClassTest::name);
    return m.ptr();

#!/usr/bin/env python3

import class_test

my_class_test = class_test.ClassTest("abc");
assert(my_class_test.getName() ==

Compile and run:

#!/usr/bin/env bash
set -eux
g++ `python3-config --cflags` -shared -std=c++11 -fPIC class_test.cpp \
  -o class_test`python3-config --extension-suffix` `python3-config --libs`

This example shows how pybind11 allows you to effortlessly expose the ClassTest C++ class to Python! Compilation produces a file named which automatically picks up as the definition point for the class_test natively defined module.

Perhaps the realization of how awesome this is only sinks in if you try to do the same thing by hand with the native Python API, see for example this example of doing that, which has about 10x more code: On that example you can see how the C code has to painfully and explicitly define the Python class bit by bit with all the information it contains (members, methods, further metadata...). See also:

pybind11 claims to be similar to Boost.Python which was mentioned at but more minimal because it is freed from the bloat of being inside the Boost project:

pybind11 is a lightweight header-only library that exposes C++ types in Python and vice versa, mainly to create Python bindings of existing C++ code. Its goals and syntax are similar to the excellent Boost.Python library by David Abrahams: to minimize boilerplate code in traditional extension modules by inferring type information using compile-time introspection.

The main issue with Boost.Python—and the reason for creating such a similar project—is Boost. Boost is an enormously large and complex suite of utility libraries that works with almost every C++ compiler in existence. This compatibility has its cost: arcane template tricks and workarounds are necessary to support the oldest and buggiest of compiler specimens. Now that C++11-compatible compilers are widely available, this heavy machinery has become an excessively large and unnecessary dependency.

Think of this library as a tiny self-contained version of Boost.Python with everything stripped away that isn't relevant for binding generation. Without comments, the core header files only require ~4K lines of code and depend on Python (2.7 or 3.x, or PyPy2.7 >= 5.7) and the C++ standard library. This compact implementation was possible thanks to some of the new C++11 language features (specifically: tuples, lambda functions and variadic templates). Since its creation, this library has grown beyond Boost.Python in many ways, leading to dramatically simpler binding code in many common situations.

pybind11 is also the only non-native alternative hightlighted by the current Microsoft Python C binding documentation at: (archive).

Tested on Ubuntu 18.04, pybind11 2.0.1, Python 3.6.8, GCC 7.4.0.

Create array of regex matches

From the Official Regex Java Trails:

        Pattern pattern = 
        Pattern.compile(console.readLine("%nEnter your regex: "));

        Matcher matcher = 
        pattern.matcher(console.readLine("Enter input string to search: "));

        boolean found = false;
        while (matcher.find()) {
            console.format("I found the text \"%s\" starting at " +
               "index %d and ending at index %d.%n",
      , matcher.start(), matcher.end());
            found = true;

Use find and insert the resulting group at your array / List / whatever.

Showing empty view when ListView is empty

Just to add that you don't really need to create new IDs, something like the following will work.

In the layout:



Then in the activity:

    ListView listView = (ListView) findViewById(;

How to get Toolbar from fragment?

You need to cast your activity from getActivity() to AppCompatActivity first. Here's an example:

((AppCompatActivity) getActivity()).getSupportActionBar().setTitle();

The reason you have to cast it is because getActivity() returns a FragmentActivity and you need an AppCompatActivity

In Kotlin:

(activity as AppCompatActivity).supportActionBar?.title = "My Title"

python: unhashable type error

I don't think converting to a tuple is the right answer. You need go and look at where you are calling the function and make sure that c is a list of list of strings, or whatever you designed this function to work with

For example you might get this error if you passed [c] to the function instead of c

Is there any way to start with a POST request using Selenium?

Selenium doesn't currently offer API for this, but there are several ways to initiate an HTTP request in your test. It just depends what language you are writing in.

In Java for example, it might look like this:

// setup the request
String request = "startpoint?stuff1=foo&stuff2=bar";
URL url = new URL(request);
HttpURLConnection connection = (HttpURLConnection) url.openConnection();

// get a response - maybe "success" or "true", XML or JSON etc.
InputStream inputStream = connection.getInputStream();
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
String line;
StringBuffer response = new StringBuffer();
while ((line = bufferedReader.readLine()) != null) {

// continue with test
if (response.toString().equals("expected response"){
    // do selenium

Are there any Java method ordering conventions?

Are you using Eclipse? If so I would stick with the default member sort order, because that is likely to be most familiar to whoever reads your code (although it is not my favourite sort order.)

How to customize message box

You can't restyle the default MessageBox as that's dependant on the current Windows OS theme, however you can easily create your own MessageBox. Just add a new form (i.e. MyNewMessageBox) to your project with these settings:

FormBorderStyle    FixedToolWindow
ShowInTaskBar      False
StartPosition      CenterScreen

To show it use myNewMessageBoxInstance.ShowDialog();. And add a label and buttons to your form, such as OK and Cancel and set their DialogResults appropriately, i.e. add a button to MyNewMessageBox and call it btnOK. Set the DialogResult property in the property window to DialogResult.OK. When that button is pressed it would return the OK result:

MyNewMessageBox myNewMessageBoxInstance = new MyNewMessageBox();
DialogResult result = myNewMessageBoxInstance.ShowDialog();
if (result == DialogResult.OK)
    // etc

It would be advisable to add your own Show method that takes the text and other options you require:

public DialogResult Show(string text, Color foreColour)
     lblText.Text = text;
     lblText.ForeColor = foreColour;
     return this.ShowDialog();

Reading a cell value in Excel vba and write in another Cell

I have this function for this case ..

Function GetValue(r As Range, Tag As String) As Integer
Dim c, nRet As String
Dim n, x As Integer
Dim bNum As Boolean

c = r.Value
n = InStr(c, Tag)
For x = n + 1 To Len(c)
  Select Case Mid(c, x, 1)
    Case ":":    bNum = True
    Case " ": Exit For
    Case Else: If bNum Then nRet = nRet & Mid(c, x, 1)
  End Select
GetValue = val(nRet)
End Function

To fill cell BC .. (assumed that you check cell A1)

Worksheets("Übersicht_2013").Cells(i, "BC") = GetValue(range("A1"),"S")

PHP equivalent of .NET/Java's toString()

You can either use typecasting:

$var = (string)$varname;

or StringValue:

$var = strval($varname);

or SetType:

$success = settype($varname, 'string');
// $varname itself becomes a string

They all work for the same thing in terms of Type-Juggling.

Android device does not show up in adb list

I also had same problem, i tried to use all the possible solution posted on this thread, but i found out i had same problem as JohnnyFun explained, but as per HenrikB solution i could not find any settings option in my Samsung Galaxy S6 phone ( Android 6.0.1)

Settings -> Storage -> menu -> USB computer connection

I finally figure - when connecting my phone throught charger in pull down menu i see options like -

enter image description here

Then click on "Connected for chargin " >>> you will see options like >>

enter image description here

Over there you can change option to "Transferring media type files"

React-router urls don't work when refreshing or writing manually

If you are hosting in IIS ; Adding this to my webconfig solved my problem

<httpErrors errorMode="Custom" defaultResponseMode="ExecuteURL">
    <remove statusCode="500" subStatusCode="100" />
    <remove statusCode="500" subStatusCode="-1" />
    <remove statusCode="404" subStatusCode="-1" />
    <error statusCode="404" path="/" responseMode="ExecuteURL" />
    <error statusCode="500" prefixLanguageFilePath="" path="/error_500.asp" responseMode="ExecuteURL" />
    <error statusCode="500" subStatusCode="100" path="/error_500.asp" responseMode="ExecuteURL" />

You can make similar configuration for any other server

Converting 'ArrayList<String> to 'String[]' in Java

In Java 11, we can use the Collection.toArray(generator) method. The following code will create a new array of strings:

List<String> list = List.of("one", "two", "three");
String[] array = list.toArray(String[]::new)

from java.base's java.util.Collection.toArray().

Setting a system environment variable from a Windows batch file?

System variables can be set through CMD and registry For ex. reg query "HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Environment" /v PATH

All the commonly used CMD codes and system variables are given here: Set Windows system environment variables using CMD.

Open CMD and type Set

You will get all the values of system variable.

Type set java to know the path details of java installed on your window OS.

Variables not showing while debugging in Eclipse

If you are able to jump on breakpoints, it is ok to Reset Perspective.

On Eclipse Version: Luna Service Release 2 (4.4.2) Build id: 20150219-0600 I notived that not only the Variable View was empty, but also the buttons to navigate the execution (F5, F6, F8 functionality buttons) were disabled. In this case, go to Debug View, right click to the row with the yellow pause symbol, and choose an option like "Resume". On the next breakpoint, Variable View will be automagically fullfilled and execution navigation buttons will be enabled. Can't explain why

Using gradle to find dependency tree

Note that you may need to do something like ./gradlew <module_directory>:<module_name>:dependencies if the module has extra directory before reach its build.gradle. When in doubt, do ./gradlew tasks --all to check the name.

How to implement a tree data-structure in Java?

There are a couple of tree data structures in Java, such as DefaultMutableTreeNode in JDK Swing, Tree in Stanford parser package, and other toy codes. But none of these are sufficient yet small enough for general purpose.

Java-tree project attempts to provide another general-purpose tree data structure in Java. The difference between this and others are

  • Totally free. You can use it anywhere (except in your homework :P)
  • Small but general enough. I put everything of the data structure in one class file, so it would be easy to copy/paste.
  • Not just a toys. I am aware of dozens of Java tree codes that can only handle binary trees or limited operations. This TreeNode is much more than that. It provides different ways of visiting nodes, such as preorder, postorder, breadthfirst, leaves, path to root, etc. Moreover, iterators are provided too for the sufficiency.
  • More utils will be added. I am willing to add more operations to make this project comprehensive, especially if you send a request through github.

CSS scale down image to fit in containing div, without specifing original size

This is an old question I know, but this is in the top five for several related Google searches. Here's the CSS-only solution without changing the images to background images:

width: auto;
height: auto;
max-width: MaxSize;
max-height: MaxSize;

"MaxSize" is a placeholder for whatever max-width and max-height you want to use, in pixels or percentage. auto will increase (or decrease) the width and height to occupy the space you specify with MaxSize. It will override any defaults for images you or the viewer's browser might have for images. I've found it's especially important on Android's Firefox. Pixels or percentages work for max size. With both the height and width set to auto, the aspect ratio of the original image will be retained.

If you want to fill the space entirely and don't mind the image being larger than its original size, change the two max-widths to min-width: 100% - this will make them completely occupy their space and maintain aspect ratio. You can see an example of this with a Twitter profile's background image.

Getting all types in a namespace via reflection

Namespaces are actually rather passive in the design of the runtime and serve primarily as organizational tools. The Full Name of a type in .NET consists of the Namespace and Class/Enum/Etc. combined. If you only wish to go through a specific assembly, you would simply loop through the types returned by assembly.GetExportedTypes() checking the value of type.Namespace. If you were trying to go through all assemblies loaded in the current AppDomain it would involve using AppDomain.CurrentDomain.GetAssemblies()

How to set the env variable for PHP?

Try display phpinfo() by file and check this var.

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

I have always found Exceptions are much slower to be handled.

Perhaps a less intensive way would yeild a better, faster, result?

public bool IsValidUri(Uri uri)

    using (HttpClient Client = new HttpClient())

    HttpResponseMessage result = Client.GetAsync(uri).Result;
    HttpStatusCode StatusCode = result.StatusCode;

    switch (StatusCode)

        case HttpStatusCode.Accepted:
            return true;
        case HttpStatusCode.OK:
            return true;
            return false;

Then just use:

IsValidUri(new Uri(""));

postgres default timezone

In addition to the previous answers, if you use the tool pgAdmin III you can set the time zone as follows:

  1. Open Postgres config via Tools > Server Configuration > postgresql.conf
  2. Look for the entry timezone and double click to open
  3. Change the Value
  4. Reload Server to apply configuration changes (Play button on top or via services)

Postgres config in pgAdmin III

Aggregate a dataframe on a given column and display another column

The plyr package can be used for this. With the ddply() function you can split a data frame on one or more columns and apply a function and return a data frame, then with the summarize() function you can use the columns of the splitted data frame as variables to make the new data frame/;

dat <- read.table(textConnection('Group Score Info
1     1     1    a
2     1     2    b
3     1     3    c
4     2     4    d
5     2     3    e
6     2     1    f'))


    Max = max(Score),
    Info = Info[which.max(Score)])
  Group Max Info
1     1   3    c
2     2   4    d

PHP: How to check if image file exists?

You can use the file_get_contents function to access remote files. See for details.

Auto-loading lib files in Rails 4

I think this may solve your problem:

  1. in config/application.rb:

    config.autoload_paths << Rails.root.join('lib')

    and keep the right naming convention in lib.

    in lib/foo.rb:

    class Foo

    in lib/foo/bar.rb:

    class Foo::Bar
  2. if you really wanna do some monkey patches in file like lib/extensions.rb, you may manually require it:

    in config/initializers/require.rb:

    require "#{Rails.root}/lib/extensions" 


What are the differences between Mustache.js and Handlebars.js?

Mustache pros:

  • Very popular choice with a large, active community.
  • Server side support in many languages, including Java.
  • Logic-less templates do a great job of forcing you to separate presentation from logic.
  • Clean syntax leads to templates that are easy to build, read, and maintain.

Mustache cons:

  • A little too logic-less: basic tasks (e.g. label alternate rows with different CSS classes) are difficult.
  • View logic is often pushed back to the server or implemented as a "lambda" (callable function).
  • For lambdas to work on client and server, you must write them in JavaScript.

Handlebars pros:

  • Logic-less templates do a great job of forcing you to separate presentation from logic.
  • Clean syntax leads to templates that are easy to build, read, and maintain.
  • Compiled rather than interpreted templates.
  • Better support for paths than mustache (ie, reaching deep into a context object).
  • Better support for global helpers than mustache.

Handlebars cons:

  • Requires server-side JavaScript to render on the server.

Source: The client-side templating throwdown: mustache, handlebars, dust.js, and more

Access restriction on class due to restriction on required library rt.jar?

In addition to Nels Beckman's solution, I have the following tips:

Under Configure Build Path, I had to rearrange the order of my entries under Order and Export.

Additionally, as an Eclipse PDE developer, I needed to rearrange the order of my dependencies in my MANIFEST.MF, adding the problematic package as first on the list.

Playing with these dials, along with running Project > Clean in between, I was able to resolve these warnings.

Drawing Isometric game worlds

Update: Corrected map rendering algorithm, added more illustrations, changed formating.

Perhaps the advantage for the "zig-zag" technique for mapping the tiles to the screen can be said that the tile's x and y coordinates are on the vertical and horizontal axes.

"Drawing in a diamond" approach:

By drawing an isometric map using "drawing in a diamond", which I believe refers to just rendering the map by using a nested for-loop over the two-dimensional array, such as this example:

tile_map[][] = [[...],...]

for (cellY = 0; cellY < tile_map.size; cellY++):
    for (cellX = 0; cellX < tile_map[cellY].size cellX++):
            screenX = (cellX * tile_width  / 2) + (cellY * tile_width  / 2)
            screenY = (cellY * tile_height / 2) - (cellX * tile_height / 2)


The advantage to the approach is that it is a simple nested for-loop with fairly straight forward logic that works consistently throughout all tiles.


One downside to that approach is that the x and y coordinates of the tiles on the map will increase in diagonal lines, which might make it more difficult to visually map the location on the screen to the map represented as an array:

Image of tile map

However, there is going to be a pitfall to implementing the above example code -- the rendering order will cause tiles that are supposed to be behind certain tiles to be drawn on top of the tiles in front:

Resulting image from incorrect rendering order

In order to amend this problem, the inner for-loop's order must be reversed -- starting from the highest value, and rendering toward the lower value:

tile_map[][] = [[...],...]

for (i = 0; i < tile_map.size; i++):
    for (j = tile_map[i].size; j >= 0; j--):  // Changed loop condition here.
            x = (j * tile_width / 2) + (i * tile_width / 2)
            y = (i * tile_height / 2) - (j * tile_height / 2)

With the above fix, the rendering of the map should be corrected:

Resulting image from correct rendering order

"Zig-zag" approach:


Perhaps the advantage of the "zig-zag" approach is that the rendered map may appear to be a little more vertically compact than the "diamond" approach:

Zig-zag approach to rendering seems compact


From trying to implement the zig-zag technique, the disadvantage may be that it is a little bit harder to write the rendering code because it cannot be written as simple as a nested for-loop over each element in an array:

tile_map[][] = [[...],...]

for (i = 0; i < tile_map.size; i++):
    if i is odd:
        offset_x = tile_width / 2
        offset_x = 0

    for (j = 0; j < tile_map[i].size; j++):
            x = (j * tile_width) + offset_x,
            y = i * tile_height / 2

Also, it may be a little bit difficult to try to figure out the coordinate of a tile due to the staggered nature of the rendering order:

Coordinates on a zig-zag order rendering

Note: The illustrations included in this answer were created with a Java implementation of the tile rendering code presented, with the following int array as the map:

tileMap = new int[][] {
    {0, 1, 2, 3},
    {3, 2, 1, 0},
    {0, 0, 1, 1},
    {2, 2, 3, 3}

The tile images are:

  • tileImage[0] -> A box with a box inside.
  • tileImage[1] -> A black box.
  • tileImage[2] -> A white box.
  • tileImage[3] -> A box with a tall gray object in it.

A Note on Tile Widths and Heights

The variables tile_width and tile_height which are used in the above code examples refer to the width and height of the ground tile in the image representing the tile:

Image showing the tile width and height

Using the dimensions of the image will work, as long as the image dimensions and the tile dimensions match. Otherwise, the tile map could be rendered with gaps between the tiles.

Importing a Maven project into Eclipse from Git

As of this (updated) writing, a working setup is the following:

  1. Eclipse 3.8 (Eclipse Indigo update site)
  2. EGit 1.3.0 (Eclipse Indigo update site)
  3. m2e 1.0.200 (Eclipse Indigo update site)
  4. m2e-egit 0.14.0 (m2e marketplace when adding a connector)

Tested on Ubuntu Raring.

You can certainly "Import" -> "Maven" -> "Check out Maven Projects from SCM", and this is the quickest way. However, such direct import currently does not give you control over the cloned repository folder name. You may be better off working from the "Git Repository" View and perform either a "Clone from a Git Repository and add the clone to this view", followed by an "Import Maven Projects" from such clone; the longest way would be to do your manual cloning and then "Add an existing local Git Repository to this view", followed again by an "Import Maven Projects". Either case you have full control on the cloned folder.

A final comment on a side issue that made me cry in frustration. As far as I know, if the cloned repository lies on the root of your Eclipse workspace, and your Maven project file hierarchy has a POM on its root, then importing such root project will rename the cloned folder (with the template you chose, defaults to [artifactId]). Without changing your project structure and without keeping files outside your workspace, you can easily work around this issue by cloning on a subsubfolder of the workspace folder.

How can I get the list of files in a directory using C or C++?

C++17 now has a std::filesystem::directory_iterator, which can be used as

#include <string>
#include <iostream>
#include <filesystem>
namespace fs = std::filesystem;

int main() {
    std::string path = "/path/to/directory";
    for (const auto & entry : fs::directory_iterator(path))
        std::cout << entry.path() << std::endl;

Also, std::filesystem::recursive_directory_iterator can iterate the subdirectories as well.

Get top 1 row of each group

I just learned how to use cross apply. Here's how to use it in this scenario:

 select d.DocumentID, ds.Status, ds.DateCreated 
 from Documents as d 
 cross apply 
     (select top 1 Status, DateCreated
      from DocumentStatusLogs 
      where DocumentID = d.DocumentId
      order by DateCreated desc) as ds

Check if item is in an array / list

Assuming you mean "list" where you say "array", you can do

if item in my_list:
    # whatever

This works for any collection, not just for lists. For dictionaries, it checks whether the given key is present in the dictionary.

Get the current script file name

Here is the difference between basename(__FILE__, ".php") and basename($_SERVER['REQUEST_URI'], ".php").

basename(__FILE__, ".php") shows the name of the file where this code is included - It means that if you include this code in header.php and current page is index.php, it will return header not index.

basename($_SERVER["REQUEST_URI"], ".php") - If you use include this code in header.php and current page is index.php, it will return index not header.

Execution Failed for task :app:compileDebugJavaWithJavac in Android Studio

I encountered the same error. JAVA_HOME pointing to the correct version of JDK. All support libraries and build tools updated. Was still facing the same issue.

I am using Android annotations in my project. I added a new View..and there was already an existing view with the same name in the Java file. When I run the project, instead of indicating the view already exists, I was receiving the above error.

Check your java files errors if other solutions does not work.

history.replaceState() example?

Indeed this is a bug, although intentional for 2 years now. The problem lies with some unclear specs and the complexity when document.title and back/forward are involved.

See bug reference on Webkit and Mozilla. Also Opera on the introduction of History API said it wasn't using the title parameter and probably still doesn't.

Currently the 2nd argument of pushState and replaceState — the title of the history entry — isn't used in Opera's implementation, but may be one day.

Potential solution

The only way I see is to alter the title element and use pushState instead:

document.getElementsByTagName('title')[0].innerHTML = 'bar';
window.history.pushState( {} , 'bar', '/bar' );

Cannot start MongoDB as a service

Have your checked you logging to see the real problem?

I suggest extracting the Mongo installation to c:\mongodb.

Create the c:\mongodb\logs and the c:\mongodb\data\db directories.

Then browse the the c:\mongodb\bin directory and run the following to remove the service (if you've installed it!):

mongod --remove

Then install the service, specifying the log and data directories:

mongod --logpath c:\mongodb\logs\mongo.log --dbpath c:\mongodb\data\db --directoryperdb --install

Then if there is a problem starting the service you should see the reason in the specified log file.

More info here.

How do I change the select box arrow

Working with just one selector:

select {
    width: 268px;
    padding: 5px;
    font-size: 16px;
    line-height: 1;
    border: 0;
    border-radius: 5px;
    height: 34px;
    background: url( no-repeat right #ddd;
    -webkit-appearance: none;
    background-position-x: 244px;


How to copy and edit files in Android shell?

I could suggest just install Terminal-ide on you device which available in play market. Its free, does not require root and provide convenient *nix environment like cp, find, du, mc and many other utilities which installed in binary form by one button tap.

Exporting data In SQL Server as INSERT INTO

You could also check out the "Data Scripter Add-In" for SQL Server Management Studio 2008 from:

Their features list:

  • It was developed on SSMS 2008 and is not supported on the 2005 version at this time (soon!)

  • Export data quickly to T-SQL for MSSQL and MySQL syntax

  • CSV, TXT, XML are also supported! Harness the full potential, power, and speed that SQL has to offer.

  • Don't wait for Access or Excel to do scripting work for you that could take several minutes to do -- let SQL Server do it for you and take all the guess work out of exporting your data!

  • Customize your data output for rapid backups, DDL manipulation, and more...

  • Change table names and database schemas to your needs, quickly and efficiently

  • Export column names or simply generate data without the names.

  • You can chose individual columns to script.

  • You can chose sub-sets of data (WHERE clause).

  • You can chose ordering of data (ORDER BY clause).

  • Great backup utility for those grungy database debugging operations that require data manipulation. Don't lose data while experimenting. Manipulate data on the fly!

MySQL my.ini location

Open your run console type: services.msc look for: mysql right click properties where is written "path to executable", click and move the cursor to the right until you see the directory of my.ini, it's written "defaults-file-". to reach it manually on your explore folders you have to enable the visualization of hidden elements (explore folder>top menu>visualize>visualize hidden elements)

as explained by this video

Where can I find the assembly System.Web.Extensions dll?


The info below is only applicable to VS2008 and the 3.5 framework. VS2010 has a new registry location. Further details can be found on MSDN: How to Add or Remove References in Visual Studio.


It should be listed in the .NET tab of the Add Reference dialog. Assemblies that appear there have paths in registry keys under:


I have a key there named Microsoft .NET Framework 3.5 Reference Assemblies with a string value of:

C:\Program Files\Reference Assemblies\Microsoft\Framework\v3.5\

Navigating there I can see the actual System.Web.Extensions dll.


I found my .NET 4.0 version in:

C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.0\System.Web.Extensions.dll

I'm running Win 7 64 bit, so if you're on a 32 bit OS drop the (x86).

how to make a whole row in a table clickable as a link?

Here is simple solution..

<tr style='cursor: pointer; cursor: hand;' onclick="window.location='';"></tr>

CSS Animation onClick

Add a

-webkit-animation-play-state: paused;

to your CSS file, then you can control whether the animation is running or not by using this JS line:

document.getElementById("myDIV").style.WebkitAnimationPlayState = "running";

if you want the animation to run once, every time you click. Remember to set

-webkit-animation-iteration-count: 1;

how to increase the limit for max.print in R

See ?options:


Checking for #N/A in Excel cell from VBA code

First check for an error (N/A value) and then try the comparisation against cvErr(). You are comparing two different things, a value and an error. This may work, but not always. Simply casting the expression to an error may result in similar problems because it is not a real error only the value of an error which depends on the expression.

If IsError(ActiveWorkbook.Sheets("Publish").Range("G4").offset(offsetCount, 0).Value) Then
  If (ActiveWorkbook.Sheets("Publish").Range("G4").offset(offsetCount, 0).Value <> CVErr(xlErrNA)) Then
    'do something
  End If
End If

jQuery checkbox event handling

Acknowledging the fact that the asker specifically requested jQuery and that the answer selected is correct, it should be noted that this problem doesn't actually need jQuery per say. If one desires to solve this problem without it, one can simply set the onClick attribute of the checkboxes that he or she wants to add additional functionality to, like so:


<form id="myform">
  <input type="checkbox" name="check1" value="check1" onClick="cbChanged(this);">
  <input type="checkbox" name="check2" value="check2" onClick="cbChanged(this);">


function cbChanged(checkboxElem) {
  if (checkboxElem.checked) {
    // Do something special
  } else {
    // Do something else


How to split strings over multiple lines in Bash?

However, if you have indented code, it doesn't work out so well:

    echo "continuation \
>continuation     lines

Try with single quotes and concatenating the strings:

    echo 'continuation' \
>continuation lines

Note: the concatenation includes a whitespace.

Why does visual studio 2012 not find my tests?

The simplest thing you can do is, just drag and drop those files from the File Explorer to the Test project. Build the project again, and you are good to go!


Open the .csproj file of your Test project in a text editor and manually include the file name to compile. Search for the Compile tag in the file and add your file which you want to run.

    <Compile Include="TestSettings.cs" />
    <Compile Include="TestLibrary.cs" />
    <Compile Include="UnitTest1.cs" />

Add the Compile tag for your file and save it. Now run the tests. Your file with unit test will be detected and run.

Adding header to all request with Retrofit 2

Kotlin version would be

fun getHeaderInterceptor():Interceptor{
    return object : Interceptor {
        override fun intercept(chain: Interceptor.Chain): Response {
            val request =
                    .header(Headers.KEY_AUTHORIZATION, "Bearer.....")
            return chain.proceed(request)

private fun createOkHttpClient(): OkHttpClient {
    return OkHttpClient.Builder()
            .apply {

Sorting a list with stream.sorted() in Java

This is a simple example :

List<String> citiesName = Arrays.asList( "Delhi","Mumbai","Chennai","Banglore","Kolkata");
System.out.println("Cities : "+citiesName);
List<String> sortedByName =
System.out.println("Sorted by Name : "+ sortedByName);

It may be possible that your IDE is not getting the jdk 1.8 or upper version to compile the code.

Set the Java version 1.8 for Your_Project > properties > Project Facets > Java version 1.8

What's a simple way to get a text input popup dialog box on an iPhone

Tested out Warkst's third code snippet--worked great, except I changed it to be default input type instead of numeric:

UIAlertView * alert = [[UIAlertView alloc] initWithTitle:@"Hello!" message:@"Please enter your name:" delegate:self cancelButtonTitle:@"Continue" otherButtonTitles:nil];
alert.alertViewStyle = UIAlertViewStylePlainTextInput;
UITextField * alertTextField = [alert textFieldAtIndex:0];
alertTextField.keyboardType = UIKeyboardTypeDefault;
alertTextField.placeholder = @"Enter your name";
[alert show];

JFrame Maximize window

Something like this.setExtendedState(this.getExtendedState() | this.MAXIMIZED_BOTH);

import java.awt.*;
import javax.swing.*;

public class Test extends JFrame
    public Test()
        GraphicsEnvironment env =
        this.setExtendedState(this.getExtendedState() | this.MAXIMIZED_BOTH);

    public static void main(String[] args)

        Test t = new Test();

GetType used in PowerShell, difference between variables

First of all, you lack parentheses to call GetType. What you see is the MethodInfo describing the GetType method on [DayOfWeek]. To actually call GetType, you should do:


You should see that $a is a [DayOfWeek], and $b is a custom object generated by the Select-Object cmdlet to capture only the DayOfWeek property of a data object. Hence, it's an object with a DayOfWeek property only:

C:\> $b.DayOfWeek -eq $a

Finding a substring within a list in Python

I'd just use a simple regex, you can do something like this

import re
old_list = ['abc123', 'def456', 'ghi789']
new_list = [x for x in old_list if'abc', x)]
for item in new_list:
    print item

How do I get the title of the current active window using c#?

you can use process class it's very easy. use this namespace

using System.Diagnostics;

if you want to make a button to get active window.

private void button1_Click(object sender, EventArgs e)
       Process currentp = Process.GetCurrentProcess();
       TextBox1.Text = currentp.MainWindowTitle;  //this textbox will be filled with active window.

How to trigger event when a variable's value is changed?

The .NET framework actually provides an interface that you can use for notifying subscribers when a property has changed: System.ComponentModel.INotifyPropertyChanged. This interface has one event PropertyChanged. Its usually used in WPF for binding but I have found it useful in business layers as a way to standardize property change notification.

In terms of thread safety I would put a lock under in the setter so that you don't run into any race conditions.

Here are my thoughts in code :) :

public class MyClass : INotifyPropertyChanged
    private object _lock;

    public int MyProperty
            return _myProperty;
                //The property changed event will get fired whenever
                //the value changes. The subscriber will do work if the value is
                //1. This way you can keep your business logic outside of the setter
                if(value != _myProperty)
                    _myProperty = value;

    private NotifyPropertyChanged(string propertyName)
        //Raise PropertyChanged event
    public event PropertyChangedEventHandler PropertyChanged;

public class MySubscriber
    private MyClass _myClass;        

    void PropertyChangedInMyClass(object sender, PropertyChangedEventArgs e)
            case "MyProperty":

    void DoWorkOnMyProperty(int newValue)
        if(newValue == 1)
             //DO WORK HERE

Hope this is helpful :)

How to filter input type="file" dialog by specific file type?

<asp:FileUpload ID="FileUploadExcel" ClientIDMode="Static" runat="server" />
<asp:Button ID="btnUpload" ClientIDMode="Static" runat="server" Text="Upload Excel File" />


$('#btnUpload').click(function () {
    var uploadpath = $('#FileUploadExcel').val();
    var fileExtension = uploadpath.substring(uploadpath.lastIndexOf(".") + 1, uploadpath.length);

    if ($('#FileUploadExcel').val().length == 0) {
        // write error message
        return false;

    if (fileExtension == "xls" || fileExtension == "xlsx") {
        //write code for success
    else {
        //error code - select only excel files
        return false;


installing JDK8 on Windows XP - advapi32.dll error

There is also an alternate solution for those who aren't afraid of using hex editors (e.g. XVI32) [thanks to Trevor for this]: in the unpacked 1 installer executable (jdk-8uXX-windows-i586.exe in case of JDK) simply replace all occurrences of RegDeleteKeyExA (the name of API found in "new" ADVAPI32.DLL) with RegDeleteKeyA (legacy API name), followed by two hex '00's (to preserve padding/segmentation boundaries). The installer will complain about unsupported Windows version, but will work nevertheless.

For reference, the raw hex strings will be:

52 65 67 44 65 6C 65 74 65 4B 65 79 45 78 41

replaced with

52 65 67 44 65 6C 65 74 65 4B 65 79 41 00 00

Note: this procedure applies to both offline (standalone) and online (downloader) package.

1: some newer installer versions are packed with UPX - you'd need to unpack them first, otherwise you simply won't be able to find the hex string required

How to use MySQL DECIMAL?

DOUBLE columns are not the same as DECIMAL columns, and you will get in trouble if you use DOUBLE columns for financial data.

DOUBLE is actually just a double precision (64 bit instead of 32 bit) version of FLOAT. Floating point numbers are approximate representations of real numbers and they are not exact. In fact, simple numbers like 0.01 do not have an exact representation in FLOAT or DOUBLE types.

DECIMAL columns are exact representations, but they take up a lot more space for a much smaller range of possible numbers. To create a column capable of holding values from 0.0001 to 99.9999 like you asked you would need the following statement

CREATE TABLE your_table
    your_column DECIMAL(6,4) NOT NULL

The column definition follows the format DECIMAL(M, D) where M is the maximum number of digits (the precision) and D is the number of digits to the right of the decimal point (the scale).

This means that the previous command creates a column that accepts values from -99.9999 to 99.9999. You may also create an UNSIGNED DECIMAL column, ranging from 0.0000 to 99.9999.

For more information on MySQL DECIMAL the official docs are always a great resource.

Bear in mind that all of this information is true for versions of MySQL 5.0.3 and greater. If you are using previous versions, you really should upgrade.

Can I use Twitter Bootstrap and jQuery UI at the same time?

Although this question specifically mentions jQuery-UI autosuggest feature, the question title is more general: does bootstrap 3 work with jQuery UI? I was having trouble with the jQUI datepicker (pop-up calendar) feature. I solved the datepicker problem and hope the solution will help with other jQUI/BS issues.

I had a difficult time today getting the latest jQueryUI (ver 1.12.1) datepicker to work with bootstrap 3.3.7. What was happening is that the calendar would display but it would not close.

Turned out to be a version problem with jQUI and BS. I was using the latest version of Bootstrap, and found that I had to downgrade to these versions of jQUI and jQuery:

jQueryUI - 1.9.2 (tested - works)
jQuery - 1.9.1 or 2.1.4 (tested - both work. Other vers may work, but these work.)
Bootstrap 3.3.7 (tested - works)

Because I wanted to use a custom theme, I also built a custom download of jQUI (removed a few things like all the interactions, dialog, progressbar and a few effects I don't use) -- and made sure to select "Cupertino" at the bottom as my theme.

I installed them thus:

<link rel="stylesheet" href="css/font-awesome.min.css">
<link rel="stylesheet" href="css/cupertino/jquery-ui-1.9.2.custom.min.css">
<link rel="stylesheet" href="css/bootstrap-3.3.7.min.css">

<!-- <script src="js/jquery-1.9.1.min.js"></script> -->
<script src="js/jquery-2.1.4.min.js"></script>
<script src="js/jquery-ui-1.9.2.custom.min.js"></script>
<script src="js/bootstrap-3.3.7.min.js"></script>

For those interested, the CSS folder looks like this:

  - bootstrap-3.3.7.min.css
  - font-awesome.min.css
  - style.css
  - [cupertino]
      - jquery-ui-1.9.2.custom.min.css
          - ui-bg_diagonals-thick_90_eeeeee_40x40.png
          - ui-bg_glass_100_e4f1fb_1x400.png
          - ui-bg_glass_50_3baae3_1x400.png
          - ui-bg_glass_80_d7ebf9_1x400.png
          - ui-bg_highlight-hard_100_f2f5f7_1x100.png
          - etc (8 more files that were in the downloaded jQUI zip file)

How to get a shell environment variable in a makefile?

    echo ${PATH}

Or change PATH just for one command:

    PATH=/my/path:${PATH} cmd

Eclipse : Maven search dependencies doesn't work

You can get this result if you are inside a corporate proxy and the new project isn't pointing to the correct settings.xml file with the proxy credentials.

You can also get this if you are using Maven proxy (Nexus, for example) and the index into the proxy is messed up somehow. I don't know a way to describe how to fix this. Fool around with it or call the one who set up the Maven proxy.

You can also get this if the new workspace hasn't yet downloaded the index either from Maven central or from the proxy. (This is the best one as you just have to wait a while and it will work itself out.)

How do I get the last four characters from a string in C#?

It is just this:

int count = 4;
string sub = mystring.Substring(mystring.Length - count, count);

Python initializing a list of lists

The problem is that they're all the same exact list in memory. When you use the [x]*n syntax, what you get is a list of n many x objects, but they're all references to the same object. They're not distinct instances, rather, just n references to the same instance.

To make a list of 3 different lists, do this:

x = [[] for i in range(3)]

This gives you 3 separate instances of [], which is what you want

[[]]*n is similar to

l = []
x = []
for i in range(n):

While [[] for i in range(3)] is similar to:

x = []
for i in range(n):
    x.append([])   # appending a new list!

In [20]: x = [[]] * 4

In [21]: [id(i) for i in x]
Out[21]: [164363948, 164363948, 164363948, 164363948] # same id()'s for each list,i.e same object

In [22]: x=[[] for i in range(4)]

In [23]: [id(i) for i in x]
Out[23]: [164382060, 164364140, 164363628, 164381292] #different id(), i.e unique objects this time

Check if TextBox is empty and return MessageBox?

For multiple text boxes - add them into a list and show all errors into 1 messagebox.

// Append errors into 1 Message Box      

 List<string> errors = new List<string>();   

 if (string.IsNullOrEmpty(textBox1.Text))

    if (string.IsNullOrEmpty(textBox2.Text))
        errors.Add("Document Ref Code");

    if (errors.Count > 0)
        errors.Insert(0, "The following fields are empty:");
        string message = string.Join(Environment.NewLine, errors);
        MessageBox.Show(message, "errors", MessageBoxButtons.OK, MessageBoxIcon.Warning);

Enter triggers button click

My situation has two Submit buttons within the form element: Update and Delete. The Delete button deletes an image and the Update button updates the database with the text fields in the form.

Because the Delete button was first in the form, it was the default button on Enter key. Not what I wanted. The user would expect to be able to hit Enter after changing some text fields.

I found my answer to setting the default button here:

<form action="/action_page.php" method="get" id="form1">
  First name: <input type="text" name="fname"><br>
  Last name: <input type="text" name="lname"><br>
<button type="submit" form="form1" value="Submit">Submit</button>

Without using any script, I defined the form that each button belongs to using the <button> form="bla" attribute. I set the Delete button to a form that doesn't exist and set the Update button I wanted to trigger on the Enter key to the form that the user would be in when entering text.

This is the only thing that has worked for me so far.

Escape double quote in grep

The problem is that you aren't correctly escaping the input string, try:

echo "\"member\":\"time\"" | grep -e "member\""

Alternatively, you can use unescaped double quotes within single quotes:

echo '"member":"time"' | grep -e 'member"'

It's a matter of preference which you find clearer, although the second approach prevents you from nesting your command within another set of single quotes (e.g. ssh 'cmd').

Does a favicon have to be 32x32 or 16x16?

Update for 2020: Sticking to the original question of 16x16 versus 32x32 icons: the current recommendation should be to provide a 32x32 icon, skipping 16x16 entirely. All current browsers and devices support 32x32 icons. The icon will routinely be upscaled to as much as 192x192 depending on the environment (assuming there are no larger sizes available or the system didn't recognize them). Upscaling from ultra low resolution has a noticeable effect so better stick to 32x32 as the smallest baseline.

For IE, Microsoft recommends 16x16, 32x32 and 48x48 packed in the favicon.ico file.

For iOS, Apple recommends specific file names and resolutions, at most 180x180 for latest devices running iOS 8.

Android Chrome primarily uses a manifest and also relies on the Apple touch icon.

IE 10 on Windows 8.0 requires PNG pictures and a background color and IE 11 on Windows 8.1 and 10 accepts several PNG pictures declared in a dedicated XML file called browserconfig.xml.

Safari for Mac OS X El Capitan introduces an SVG icon for pinned tabs.

Some other platforms look for PNG files with various resolutions, like the 96x96 picture for Google TV or the 228x228 picture for Opera Coast.

Look at this favicon pictures list for a complete reference.

TLDR: This favicon generator can generate all these files at once. The generator can also be implemented as a WordPress plugin. Full disclosure: I am the author of this site.

JQuery post JSON object to a server

To send json to the server, you first have to create json

function sendData() {
        url: '/helloworld',
        type: 'POST',
        contentType: 'application/json',
        data: JSON.stringify({
        dataType: 'json'

This is how you would structure the ajax request to send the json as a post var.

function sendData() {
        url: '/helloworld',
        type: 'POST',
        data: { json: JSON.stringify({
        dataType: 'json'

The json will now be in the json post var.

How do I set the size of an HTML text box?

Lookout! The width attribute is clipped by the max-width attribute. So I used....

    <form method="post" style="width:1200px">
    <h4 style="width:1200px">URI <input type="text" name="srcURI" id="srcURI" value="@m.SrcURI" style="width:600px;max-width:600px"/></h4>

How to set the title text color of UIButton?

Swift UI solution

Button(action: {}) {
        }.foregroundColor(Color(red: 1.0, green: 0.0, blue: 0.0))

Swift 3, Swift 4, Swift 5

to improve comments. This should work:

button.setTitleColor(.red, for: .normal)

Adding Access-Control-Allow-Origin header response in Laravel 5.3 Passport

For those who didn't solve the problem setting route middleware in App\Http\Kernel, try to set global middleware. In App\Http\Middleware\Cors:

public function handle($request, Closure $next)
    return $next($request)->header('Access-Control-Allow-Origin', '*')
        ->header('Access-Control-Allow-Methods','GET', 'POST', 'PUT', 'PATCH', 'DELETE', 'OPTIONS')
        ->header('Access-Control-Allow-Headers', 'Content-Type, Authorization');

In App\Http\Kernel:

protected $middleware = [

Extract value of attribute node via XPath

As answered above:


will only output the name attribute of the 4 child nodes belonging to the Parent specified by its predicate [@id=1]. You'll then need to change the predicate to [@id=2] to get the set of child nodes for the next Parent.

However, if you ignore the Parent node altogether and use:


you can select name attribute of all child nodes in one go.


Reading a plain text file in Java

Use Java kiss if this is about simplicity of structure:

import static kiss.API.*;

class App {
  void run() {
    String line;
    try (Close in = inOpen("file.dat")) {
      while ((line = readLine()) != null) {

Getting Date or Time only from a DateTime Object

You can also use DateTime.Now.ToString("yyyy-MM-dd") for the date, and DateTime.Now.ToString("hh:mm:ss") for the time.

Remove HTML tags from string including &nbsp in C#

I took @Ravi Thapliyal's code and made a method: It is simple and might not clean everything, but so far it is doing what I need it to do.

public static string ScrubHtml(string value) {
    var step1 = Regex.Replace(value, @"<[^>]+>|&nbsp;", "").Trim();
    var step2 = Regex.Replace(step1, @"\s{2,}", " ");
    return step2;

Syntax error "syntax error, unexpected end-of-input, expecting keyword_end (SyntaxError)"

Do you perhaps have one too many here?

 describe "when name is too long" do
     before { = "a" * 51 }
     it { should_not be_valid }

How do I get the n-th level parent of an element in jQuery?

If you have a common parent div you can use parentsUntil() link

eg: $('#element').parentsUntil('.commonClass')

Advantage is that you need not to remember how many generation are there between this element and the common parent(defined by commonclass).

Tool for comparing 2 binary files in Windows

I prefer to use objcopy to convert to hex, then use diff.

What HTTP status response code should I use if the request is missing a required parameter?

I often use a 403 Forbidden error. The reasoning is that the request was understood, but I'm not going to do as asked (because things are wrong). The response entity explains what is wrong, so if the response is an HTML page, the error messages are in the page. If it's a JSON or XML response, the error information is in there.

From rfc2616:

10.4.4 403 Forbidden

The server understood the request, but is refusing to fulfill it.
Authorization will not help and the request SHOULD NOT be repeated.
If the request method was not HEAD and the server wishes to make
public why the request has not been fulfilled, it SHOULD describe the reason for the refusal in the entity. If the server does not wish to make this information available to the client, the status code 404
(Not Found) can be used instead.

Rethrowing exceptions in Java without losing the stack trace

You can also wrap the exception in another one AND keep the original stack trace by passing in the Exception as a Throwable as the cause parameter:

catch (Exception e)
     throw new YourOwnException(e);

How can I run a directive after the dom has finished rendering?

It depends on how your $('site-header') is constructed.

You can try to use $timeout with 0 delay. Something like:

return function(scope, element, attrs) {
        $('.main').height( $('.site-header').height() -  $('.site-footer').height() );

Explanations how it works: one, two.

Don't forget to inject $timeout in your directive:

.directive('sticky', function($timeout)

Server.UrlEncode vs. HttpUtility.UrlEncode

Server.UrlEncode() is there to provide backward compatibility with Classic ASP,


Is equivalent to:

HttpUtility.UrlEncode(str, Response.ContentEncoding);

Can I scale a div's height proportionally to its width using CSS?

If you want vertical sizing proportional to a width set in pixels on an enclosing div, I believe you need an extra element, like so:


<div class="ptest">
    <div class="ptest-wrap">
        <div class="ptest-inner">
            Put content here

.ptest {
  width: 200px;
  position: relative;

.ptest-wrap {
    padding-top: 60%;
.ptest-inner {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: #333;

Here's the 2 div solution that doesn't work. Note the 60% vertical padding is proportional to the window width, not the div.ptest width:

Here's the example with the code above, which does work:

How to call a JavaScript function within an HTML body

Try wrapping the createtable(); statement in a <script> tag:



I would avoid using document.write() and use the DOM if I were you though.

Making a triangle shape using xml definitions?

        android:orientation="horizontal" >

        android:toDegrees="45" >
        <shape android:shape="rectangle" >
                android:color="@color/black_color" />

            <solid android:color="@color/white" />

            <padding android:left="1dp" />
<item android:top="200dp">
    <shape android:shape="line" >
            android:color="@color/black_color" />

        <solid android:color="@color/white" /> 

Merge Two Lists in R

Here's some code that I ended up writing, based upon @Andrei's answer but without the elegancy/simplicity. The advantage is that it allows a more complex recursive merge and also differs between elements that should be connected with rbind and those that are just connected with c:

# Decided to move this outside the mapply, not sure this is 
# that important for speed but I imagine redefining the function
# might be somewhat time-consuming
mergeLists_internal <- function(o_element, n_element){
  if (is.list(n_element)){
    # Fill in non-existant element with NA elements
    if (length(n_element) != length(o_element)){
      n_unique <- names(n_element)[! names(n_element) %in% names(o_element)]
      if (length(n_unique) > 0){
        for (n in n_unique){
          if (is.matrix(n_element[[n]])){
            o_element[[n]] <- matrix(NA, 
            o_element[[n]] <- rep(NA, 

      o_unique <- names(o_element)[! names(o_element) %in% names(n_element)]
      if (length(o_unique) > 0){
        for (n in o_unique){
          if (is.matrix(n_element[[n]])){
            n_element[[n]] <- matrix(NA, 
            n_element[[n]] <- rep(NA, 

    # Now merge the two lists

    new_cols <- ifelse(is.matrix(n_element), ncol(n_element), length(n_element))
    old_cols <- ifelse(is.matrix(o_element), ncol(o_element), length(o_element))
    if (new_cols != old_cols)
      stop("Your length doesn't match on the elements,",
           " new element (", new_cols , ") !=",
           " old element (", old_cols , ")")

mergeLists <- function(old, new){
  if (is.null(old))
    return (new)

  m <- mapply(mergeLists_internal, old, new, SIMPLIFY=FALSE)

Here's my example:

v1 <- list("a"=c(1,2), b="test 1", sublist=list(one=20:21, two=21:22))
v2 <- list("a"=c(3,4), b="test 2", sublist=list(one=10:11, two=11:12, three=1:2))
mergeLists(v1, v2)

This results in:

     [,1] [,2]
[1,]    1    2
[2,]    3    4

[1] "test 1" "test 2"

     [,1] [,2]
[1,]   20   21
[2,]   10   11

     [,1] [,2]
[1,]   21   22
[2,]   11   12

     [,1] [,2]
[1,]   NA   NA
[2,]    1    2

Yeah, I know - perhaps not the most logical merge but I have a complex parallel loop that I had to generate a more customized .combine function for, and therefore I wrote this monster :-)

Excel formula to reference 'CELL TO THE LEFT'

I think this is the easiest answer.

Use a "Name" to reference the offset.

Say you want to sum a column (Column A) all the way to, but not including, the cell holding the summation (say Cell A100); do this:

(I assume you are using A1 referencing when creating the Name; R1C1 can subsequently be switched to)

  1. Click anywhere in the sheet not on the top row - say Cell D9
  2. Define a Named Range called, say "OneCellAbove", but overwrite the 'RefersTo' box with "=D8" (no quotes)
  3. Now, in Cell A100 you can use the formula

How to display full (non-truncated) dataframe information in html when converting from pandas dataframe to html?

Another way of viewing the full content of the cells in a pandas dataframe is to use IPython's display functions:

from IPython.display import HTML


Center an element in Bootstrap 4 Navbar

Why Not using bootstrap utilities. here is the code

    <nav class="navbar navbar-expand-md bg-light navbar-light fixed-top">
  <!-- Brand -->
  <a class="navbar-brand" href="#"><img src="your-logo"/></a>

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Using wire or reg with input or output in Verilog

basically reg is used to store values.For example if you want a counter(which will count and thus will have some value for each count),we will use a reg. On the other hand,if we just have a plain signal with 2 values 0 and 1,we will declare it as wire.Wire can't hold values.So assigning values to wire leads to problems....

Check if checkbox is NOT checked on click - jQuery

$(document).ready(function() {
        $("#check1").click(function() {
            var checked = $(this).is(':checked');
            if (checked) {
            } else {

Running Python on Windows for Node.js dependencies

If you're trying to use this on Cygwin, then you need to follow the instructions in this answer. (It's a problem how Cygwin treats Windows symlinks.)

Use of the MANIFEST.MF file in Java

Manifest.MF contains information about the files contained in the JAR file.

Whenever a JAR file is created a default file is created inside META-INF folder and it contains the default entries like this:

Manifest-Version: 1.0
Created-By: 1.7.0_06 (Oracle Corporation)

These are entries as “header:value” pairs. The first one specifies the manifest version and second one specifies the JDK version with which the JAR file is created.

Main-Class header: When a JAR file is used to bundle an application in a package, we need to specify the class serving an entry point of the application. We provide this information using ‘Main-Class’ header of the manifest file,

Main-Class: {fully qualified classname}

The ‘Main-Class’ value here is the class having main method. After specifying this entry we can execute the JAR file to run the application.

Class-Path header: Most of the times we need to access the other JAR files from the classes packaged inside application’s JAR file. This can be done by providing their fully qualified paths in the manifest file using ‘Class-Path’ header,

Class-Path: {jar1-name jar2-name directory-name/jar3-name}

This header can be used to specify the external JAR files on the same local network and not inside the current JAR.

Package version related headers: When the JAR file is used for package versioning the following headers are used as specified by the Java language specification:

Headers in a manifest
Header                  | Definition
Name                    | The name of the specification.
Specification-Title     | The title of the specification.
Specification-Version   | The version of the specification.
Specification-Vendor    | The vendor of the specification.
Implementation-Title    | The title of the implementation.
Implementation-Version  | The build number of the implementation.
Implementation-Vendor   | The vendor of the implementation.

Package sealing related headers:

We can also specify if any particular packages inside a JAR file should be sealed meaning all the classes defined in that package must be archived in the same JAR file. This can be specified with the help of ‘Sealed’ header,

Name: {package/some-package/} Sealed:true

Here, the package name must end with ‘/’.

Enhancing security with manifest files:

We can use manifest files entries to ensure the security of the web application or applet it packages with the different attributes as ‘Permissions’, ‘Codebae’, ‘Application-Name’, ‘Trusted-Only’ and many more.

META-INF folder:

This folder is where the manifest file resides. Also, it can contain more files containing meta data about the application. For example, in an EJB module JAR file, this folder contains the EJB deployment descriptor for the EJB module along with the manifest file for the JAR. Also, it contains the xml file containing mapping of an abstract EJB references to concrete container resources of the application server on which it will be run.


Xcode5 "No matching provisioning profiles found issue" (but good at xcode4)

I have 2 targets in my project, Free and Paid. My mistake was i was looking at my free target while trying to build the paid target, a stupid mistake but possible someone out there might learn from this as well.

In Firebase, is there a way to get the number of children of a node without loading all the node data?

Save the count as you go - and use validation to enforce it. I hacked this together - for keeping a count of unique votes and counts which keeps coming up!. But this time I have tested my suggestion! (notwithstanding cut/paste errors!).

The 'trick' here is to use the node priority to as the vote count...

The data is:

vote/$issueBeingVotedOn/user/$uniqueIdOfVoter = thisVotesCount, priority=thisVotesCount vote/$issueBeingVotedOn/count = 'user/'+$idOfLastVoter, priority=CountofLastVote

,"vote": {
  ".read" : true
  ,".write" : true
  ,"$issue" : {
    "user" : {
      "$user" : {
        ".validate" : "!data.exists() && 
             newData.val()==data.parent().parent().child('count').getPriority()+1 &&

user can only vote once && count must be one higher than current count && data value must be same as priority.

    ,"count" : {
      ".validate" : "data.parent().child(newData.val()).val()==newData.getPriority() &&
             newData.getPriority()==data.getPriority()+1 "

count (last voter really) - vote must exist and its count equal newcount, && newcount (priority) can only go up by one.


Test script to add 10 votes by different users (for this example, id's faked, should user auth.uid in production). Count down by (i--) 10 to see validation fail.

<script src=''></script>
  window.fb = new Firebase('');
  window.fb.child('count').once('value', function (dss) {
    votes = dss.getPriority();
    for (var i=1;i<10;i++) vote(dss,i+votes);
  } );

function vote(dss,count)
  var user='user/zz' + count; // replace with or whatever

The 'risk' here is that a vote is cast, but the count not updated (haking or script failure). This is why the votes have a unique 'priority' - the script should really start by ensuring that there is no vote with priority higher than the current count, if there is it should complete that transaction before doing its own - get your clients to clean up for you :)

The count needs to be initialised with a priority before you start - forge doesn't let you do this, so a stub script is needed (before the validation is active!).

Calling Javascript function from server side

You can call the function from code behind like this :


protected void MyButton_Click(object sender, EventArgs e)
    Page.ClientScript.RegisterStartupScript(this.GetType(), "myScript", "AnotherFunction();", true);


<html xmlns="">
<head id="Head1" runat="server">
<title>My Page</title>
<script src="" type="text/javascript"></script>
<script type="text/javascript">
    function Test() {
    function AnotherFunction()
        alert("This is another function");
<form id="form2" runat="server">
            <asp:RadioButtonList ID="SearchCategory" runat="server" onchange="Test()"  RepeatDirection="Horizontal"  BorderStyle="Solid">
    <tr id="ButtonRow"style="display:none">
            <asp:Button ID="MyButton" runat="server" Text="Click Here" OnClick="MyButton_Click" />

How can I add new keys to a dictionary?

You can create one:

class myDict(dict):

    def __init__(self):
        self = dict()

    def add(self, key, value):
        self[key] = value

## example

myd = myDict()


{'apples': 6, 'bananas': 3}

PySpark: withColumn() with two conditions and three outcomes

There are a few efficient ways to implement this. Let's start with required imports:

from pyspark.sql.functions import col, expr, when

You can use Hive IF function inside expr:

new_column_1 = expr(
    """IF(fruit1 IS NULL OR fruit2 IS NULL, 3, IF(fruit1 = fruit2, 1, 0))"""

or when + otherwise:

new_column_2 = when(
    col("fruit1").isNull() | col("fruit2").isNull(), 3
).when(col("fruit1") == col("fruit2"), 1).otherwise(0)

Finally you could use following trick:

from pyspark.sql.functions import coalesce, lit

new_column_3 = coalesce((col("fruit1") == col("fruit2")).cast("int"), lit(3))

With example data:

df = sc.parallelize([
    ("orange", "apple"), ("kiwi", None), (None, "banana"), 
    ("mango", "mango"), (None, None)
]).toDF(["fruit1", "fruit2"])

you can use this as follows:

    .withColumn("new_column_1", new_column_1)
    .withColumn("new_column_2", new_column_2)
    .withColumn("new_column_3", new_column_3))

and the result is:

|orange| apple|           0|           0|           0|
|  kiwi|  null|           3|           3|           3|
|  null|banana|           3|           3|           3|
| mango| mango|           1|           1|           1|
|  null|  null|           3|           3|           3|

Setting session variable using javascript

A session is stored server side, you can't modify it with JavaScript. Sessions may contain sensitive data.

You can modify cookies using document.cookie.

You can easily find many examples how to modify cookies.

Case-insensitive search

Yeah, use .match, rather than .search. The result from the .match call will return the actual string that was matched itself, but it can still be used as a boolean value.

var string = "Stackoverflow is the BEST";
var result = string.match(/best/i);
// result == 'BEST';

if (result){

Using a regular expression like that is probably the tidiest and most obvious way to do that in JavaScript, but bear in mind it is a regular expression, and thus can contain regex metacharacters. If you want to take the string from elsewhere (eg, user input), or if you want to avoid having to escape a lot of metacharacters, then you're probably best using indexOf like this:

matchString = 'best';
// If the match string is coming from user input you could do
// matchString = userInput.toLowerCase() here.

if (string.toLowerCase().indexOf(matchString) != -1){

Nth max salary in Oracle

Refer following query for getting nth highest salary. By this way you get nth highest salary. If you want get nth lowest salary only you need to replace DESC by ASC in the query. for getting highest salary of employee.

undefined reference to WinMain@16 (codeblocks)

When there's no project, Code::Blocks only compiles and links the current file. That file, from your picture, is secrypt.cpp, which does not have a main function. In order to compile and link both source files, you'll need to do it manually or add them to the same project.

Contrary to what others are saying, using a Windows subsystem with main will still work, but there will be no console window.

Your other attempt, compiling and linking just trial.cpp, never links secrypt.cpp. This would normally result in an undefined reference to jRegister(), but you've declared the function inside main instead of calling it. Change main to:

int main()

    return 0;

Build a simple HTTP server in C

There is a duplicate with more responses.

One candidate not mentioned yet is spserver.

How to push both value and key into PHP array

You can use the union operator (+) to combine arrays and keep the keys of the added array. For example:


$arr1 = array('foo' => 'bar');
$arr2 = array('baz' => 'bof');
$arr3 = $arr1 + $arr2;


// prints:
// array(
//   'foo' => 'bar',
//   'baz' => 'bof',
// );

So you could do $_GET += array('one' => 1);.

There's more info on the usage of the union operator vs array_merge in the documentation at

How to make asynchronous HTTP requests in PHP

  1. Fake a request abortion using CURL setting a low CURLOPT_TIMEOUT_MS

  2. set ignore_user_abort(true) to keep processing after the connection closed.

With this method no need to implement connection handling via headers and buffer too dependent on OS, Browser and PHP version

Master process

function async_curl($background_process=''){

    //-------------get curl contents----------------

    $ch = curl_init($background_process);
    curl_setopt_array($ch, array(
        CURLOPT_HEADER => 0,
        CURLOPT_NOSIGNAL => 1, //to timeout immediately if the value is < 1000 ms
        CURLOPT_TIMEOUT_MS => 50, //The maximum number of mseconds to allow cURL functions to execute
        CURLOPT_VERBOSE => 1,
        CURLOPT_HEADER => 1
    $out = curl_exec($ch);

    //-------------parse curl contents----------------

    //$header_size = curl_getinfo($ch, CURLINFO_HEADER_SIZE);
    //$header = substr($out, 0, $header_size);
    //$body = substr($out, $header_size);


    return true;


Background process


//do something...


If you want cURL to timeout in less than one second, you can use CURLOPT_TIMEOUT_MS, although there is a bug/"feature" on "Unix-like systems" that causes libcurl to timeout immediately if the value is < 1000 ms with the error "cURL Error (28): Timeout was reached". The explanation for this behavior is:


The solution is to disable signals using CURLOPT_NOSIGNAL


How to open a local disk file with JavaScript?

The HTML5 fileReader facility does allow you to process local files, but these MUST be selected by the user, you cannot go rooting about the users disk looking for files.

I currently use this with development versions of Chrome (6.x). I don't know what other browsers support it.

How to read values from properties file?

I wanted an utility class which is not managed by spring, so no spring annotations like @Component, @Configuration etc. But I wanted the class to read from

I managed to get it working by getting the class to be aware of the Spring Context, hence is aware of Environment, and hence environment.getProperty() works as expected.

To be explicit, I have:


import org.springframework.core.env.Environment;

// No spring annotations here
public class Utils {
    public String execute(String cmd) {
        // Making the class Spring context aware
        ApplicationContextProvider appContext = new ApplicationContextProvider();
        Environment env = appContext.getApplicationContext().getEnvironment();

        // env.getProperty() works!!!
} (see Spring get current ApplicationContext)

import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.stereotype.Component;

public class ApplicationContextProvider implements ApplicationContextAware {
    private static ApplicationContext CONTEXT;

    public ApplicationContext getApplicationContext() {
        return CONTEXT;

    public void setApplicationContext(ApplicationContext context) throws BeansException {
        CONTEXT = context;

    public static Object getBean(String beanName) {
        return CONTEXT.getBean(beanName);

Common elements comparison between 2 lists

this is my proposition i think its easier with sets than with a for loop

def unique_common_items(list1, list2):
   # Produce the set of *unique* common items in two lists.
   return list(set(list1) & set(list2))

How to concatenate string variables in Bash

I do it this way when convenient: Use an inline command!

echo "The current time is `date`"
echo "Current User: `echo $USER`"

semaphore implementation

Please check this out below sample code for semaphore implementation(Lock and unlock).

    #include <sys/types.h>
    #include <sys/ipc.h>
    #include <sys/sem.h>
    int main()
            int key,share_id,num;
            char *data;
            int semid;
            struct sembuf sb={0,-1,0};
            if(key == -1 ) {
                    printf("\n\n Initialization Falied of shared memory \n\n");
                    return 1;
            if(share_id == -1 ) {
                    printf("\n\n Error captured while share memory allocation\n\n");
                    return 1;
            data=(char *)shmat(share_id,(void *)0,0);
            strcpy(data,"Testing string\n");
            if(!fork()) { //Child Porcess
                 sb.sem_op=-1; //Lock
                 semop(share_id,(struct sembuf *)&sb,1);

                 strncat(data,"feeding form child\n",20);

                 semop(share_id,(struct sembuf *)&sb,1);
            } else {     //Parent Process
              sb.sem_op=-1; //Lock
              semop(share_id,(struct sembuf *)&sb,1);

               strncat(data,"feeding form parent\n",20);

              semop(share_id,(struct sembuf *)&sb,1);

            return 0;

How to stop/shut down an elasticsearch node?

Stopping the service and killing the daemon are indeed the correct ways to shutdown a node. However, it's not recommended to do so directly if you want to take down a node for maintenance. In fact, if you don't have replicas you will lose data.

When you directly shutdown a node, Elasticsearch will wait for 1m (default time) for it to come back online. If it doesn't, then it will start to allocate the shards from that node to other nodes wasting lots of IO.

A typical approach would be to disable shard allocation temporarily by issuing:

PUT _cluster/settings
  "persistent": {
    "cluster.routing.allocation.enable": "none"

Now, when you take down a node, ES won't try to allocate shard from that node to other nodes and you can perform you maintenance activity and then once the node is up, you can enable shard allocation again:

PUT _cluster/settings
  "persistent": {
    "cluster.routing.allocation.enable": "all"


If you don't have replicas for all your indexes, then performing this type of activity will have downtime on some of the indexes. A cleaner way in this case would be to migrate all the shards to other nodes before taking the node down:

PUT _cluster/settings
  "transient" : {
    "cluster.routing.allocation.exclude._ip" : ""

This will move all shards from to other nodes (will take time depending on the data). Once everything is done, you can kill the node, perform maintenance and get it back online. This is a slower operation and is not required if you have replicas.

(Instead of _ip, _id, _name with wildcards will work just fine.)

More information:

Other answers have explained how to kill a process.

How to bundle an Angular app for production

        **Production build with

         - Angular Rc5
         - Gulp
         - typescripts 
         - systemjs**

        1)con-cat all js files  and css files include on index.html using  "gulp-concat".
          - styles.css (all css concat in this files)
          - shims.js(all js concat in this files)

        2)copy all images and fonts as well as html files  with gulp task to "/dist".

        3)Bundling -minify angular libraries and app components mentioned in systemjs.config.js file.
         Using gulp  'systemjs-builder'

            SystemBuilder = require('systemjs-builder'),
            gulp.task('system-build', ['tsc'], function () {
                var builder = new SystemBuilder();
                return builder.loadConfig('systemjs.config.js')
                    .then(function () {
                        builder.buildStatic('assets', 'dist/app/app_libs_bundle.js')
                    .then(function () {

    4)Minify bundles  using 'gulp-uglify'

jsMinify = require('gulp-uglify'),

    gulp.task('minify', function () {
        var options = {
            mangle: false
        var js = gulp.src('dist/app/shims.js')
        var js1 = gulp.src('dist/app/app_libs_bundle.js')
        var css = gulp.src('dist/css/styles.min.css');
        return merge(js,js1, css);

5) In index.html for production 


        <meta name="viewport" content="width=device-width, initial-scale=1">
        <meta charset="utf-8" />

       <link rel="stylesheet" href="app/css/styles.min.css" />   
       <script type="text/javascript" src="app/shims.js"></script>  
       <base href="/">
     <script type="text/javascript" src="app/app_libs_bundle.js"></script> 


 6) Now just copy your dist folder to '/www' in wamp server node need to copy node_modules in www.

JAXB Exception: Class not known to this context

I had this error because I registered the wrong class in this line of code:

JAXBContext context = JAXBContext.newInstance(MyRootXmlClass.class);

Exec : display stdout "live"

There are already several answers however none of them mention the best (and easiest) way to do this, which is using spawn and the { stdio: 'inherit' } option. It seems to produce the most accurate output, for example when displaying the progress information from a git clone.

Simply do this:

var spawn = require('child_process').spawn;

spawn('coffee', ['-cw', ''], { stdio: 'inherit' });

Credit to @MorganTouvereyQuilling for pointing this out in this comment.

Stop an input field in a form from being submitted

You need to add onsubmit at your form:

<form action="YOUR_URL" method="post" accept-charset="utf-8" onsubmit="return validateRegisterForm();">

And the script will be like this:

        function validateRegisterForm(){
            alert("validation failed");
            return false;

            alert("validations passed");
            return true;

This works for me everytime :)

Is the ternary operator faster than an "if" condition in Java

Also, the ternary operator enables a form of "optional" parameter. Java does not allow optional parameters in method signatures but the ternary operator enables you to easily inline a default choice when null is supplied for a parameter value.

For example:

public void myMethod(int par1, String optionalPar2) {

    String par2 = ((optionalPar2 == null) ? getDefaultString() : optionalPar2)

In the above example, passing null as the String parameter value gets you a default string value instead of a NullPointerException. It's short and sweet and, I would say, very readable. Moreover, as has been pointed out, at the byte code level there's really no difference between the ternary operator and if-then-else. As in the above example, the decision on which to choose is based wholly on readability.

Moreover, this pattern enables you to make the String parameter truly optional (if it is deemed useful to do so) by overloading the method as follows:

public void myMethod(int par1) {
    return myMethod(par1, null);

Why doesn't list have safe "get" method like dictionary?

For small index values you can implement

my_list.get(index, default)


(my_list + [default] * (index + 1))[index]

If you know in advance what index is then this can be simplified, for example if you knew it was 1 then you could do

(my_list + [default, default])[index]

Because lists are forward packed the only fail case we need to worry about is running off the end of the list. This approach pads the end of the list with enough defaults to guarantee that index is covered.