Programs & Examples On #Jtextpane

A Java Swing text component that can be marked up with attributes that are represented graphically.

How to push a single file in a subdirectory to Github (not master)

Push only single file

git commit -m "Message goes here" filename

Push only two files.

git commit -m "Message goes here" file1 file2

Bootstrap 3 .img-responsive images are not responsive inside fieldset in FireFox

in FF use inline style i.e.

<img src="..." class="img-responsive" style="width:100%; height:auto;" />

It rocks :)

Start ssh-agent on login

So I used to use the approaches described above, but I kind of prefer the agent to die when my last bash session ends. This is a bit longer than the other solutions, but its my preferred approach. The basic idea is that the first bash session starts the ssh-agent. Then each additional bash session checks for the config file (~/.ssh/.agent_env). If that is there and there is a session running then source the environment and create a hardlink to the socket file in /tmp (needs to be on the same filesystem as the original socket file). As bash sessions shut down each deletes its own hardlink. The last session to close will find that the hardlinks have 2 links (the hardlink and the original), removal of the processes own socket and killing of the process will result in 0, leaving a clean environment after the last bash session closes.

# Start ssh-agent to keep you logged in with keys, use `ssh-add` to log in
agent=`pgrep ssh-agent -u $USER` # get only your agents           
if [[ "$agent" == "" || ! -e ~/.ssh/.agent_env ]]; then
    # if no agents or environment file is missing create a new one
    # remove old agents / environment variable files
    kill $agent running
    rm ~/.ssh/.agent_env 

    # restart
    eval `ssh-agent` 
    echo 'export SSH_AUTH_SOCK'=$SSH_AUTH_SOCK >> ~/.ssh/.agent_env             
    echo 'export SSH_AGENT_PID'=$SSH_AGENT_PID >> ~/.ssh/.agent_env             

# create our own hardlink to the socket (with random name)           
source ~/.ssh/.agent_env                                                    
ln -T $SSH_AUTH_SOCK $MYSOCK                                                
export SSH_AUTH_SOCK=$MYSOCK                                                

    # if we are the last holder of a hardlink, then kill the agent
    nhard=`ls -l $SSH_AUTH_SOCK | awk '{print $2}'`                             
    if [[ "$nhard" -eq 2 ]]; then                                               
        rm ~/.ssh/.agent_env                                                    
        ssh-agent -k                                                            
    rm $SSH_AUTH_SOCK                                                           
trap end_agent EXIT                                                             
set +x              

jQuery input button click event listener

    //Put your code here

ESLint - "window" is not defined. How to allow global variables in package.json

I found it on this page:

In package.json, this works:

"eslintConfig": {
  "globals": {
    "window": true

How to POST JSON request using Apache HttpClient?

Apache HttpClient doesn't know anything about JSON, so you'll need to construct your JSON separately. To do so, I recommend checking out the simple JSON-java library from (If "JSON-java" doesn't suit you, has a big list of libraries available in different languages.)

Once you've generated your JSON, you can use something like the code below to POST it

StringRequestEntity requestEntity = new StringRequestEntity(

PostMethod postMethod = new PostMethod("");

int statusCode = httpClient.executeMethod(postMethod);


Note - The above answer, as asked for in the question, applies to Apache HttpClient 3.1. However, to help anyone looking for an implementation against the latest Apache client:

StringEntity requestEntity = new StringEntity(

HttpPost postMethod = new HttpPost("");

HttpResponse rawResponse = httpclient.execute(postMethod);

Mixing C# & VB In The Same Project

For .net 2.0 this works. It DOES compile both in the same project if you create sub directories of in app code with the related language code. As of yet, I am looking for whether this should work in 3.5 or not though.

Switch case in C# - a constant value is expected

Now you can use nameof:

public static void Output<T>(IEnumerable<T> dataSource) where T : class
    string dataSourceName = typeof(T).Name;
    switch (dataSourceName)
        case nameof(CustomerDetails):
            var t = 123;

nameof(CustomerDetails) is basically identical to the string literal "CustomerDetails", but with a compile-time check that it refers to some symbol (to prevent a typo).

nameof appeared in C# 6.0, so after this question was asked.

Convert Variable Name to String?

print "var"
print "something_else"

Or did you mean something_else?

Getting GET "?" variable in laravel

Query params are used like this:

use Illuminate\Http\Request;

class MyController extends BaseController{

    public function index(Request $request){
         $param = $request->query('param');

How can you run a Java program without main method?

public class X { static {
  System.out.println("Main not required to print this");

Run from the cmdline with java X.

How to let an ASMX file output JSON

Are you calling the web service from client script or on the server side?

You may find sending a content type header to the server will help, e.g.

'application/json; charset=utf-8'

On the client side, I use prototype client side library and there is a contentType parameter when making an Ajax call where you can specify this. I think jQuery has a getJSON method.

Generate random string/characters in JavaScript

If a library is a possibility, Chance.js might be of help:

Magento - Retrieve products with a specific attribute value

Almost all Magento Models have a corresponding Collection object that can be used to fetch multiple instances of a Model.

To instantiate a Product collection, do the following

$collection = Mage::getModel('catalog/product')->getCollection();

Products are a Magento EAV style Model, so you'll need to add on any additional attributes that you want to return.

$collection = Mage::getModel('catalog/product')->getCollection();

//fetch name and orig_price into data

There's multiple syntaxes for setting filters on collections. I always use the verbose one below, but you might want to inspect the Magento source for additional ways the filtering methods can be used.

The following shows how to filter by a range of values (greater than AND less than)

$collection = Mage::getModel('catalog/product')->getCollection();

//filter for products whose orig_price is greater than (gt) 100

//AND filter for products whose orig_price is less than (lt) 130

While this will filter by a name that equals one thing OR another.

$collection = Mage::getModel('catalog/product')->getCollection();

//filter for products who name is equal (eq) to Widget A, or equal (eq) to Widget B
    array('attribute'=>'name','eq'=>'Widget A'),
    array('attribute'=>'name','eq'=>'Widget B'),        

A full list of the supported short conditionals (eq,lt, etc.) can be found in the _getConditionSql method in lib/Varien/Data/Collection/Db.php

Finally, all Magento collections may be iterated over (the base collection class implements on of the the iterator interfaces). This is how you'll grab your products once filters are set.

$collection = Mage::getModel('catalog/product')->getCollection();

//filter for products who name is equal (eq) to Widget A, or equal (eq) to Widget B
    array('attribute'=>'name','eq'=>'Widget A'),
    array('attribute'=>'name','eq'=>'Widget B'),        

foreach ($collection as $product) {

Defining private module functions in python

For methods: (I am not sure if this exactly what you want)

def private(method):
    def methodist(string):
        if __name__ == "__main__":
    return methodist
def private_print3(string):
    print(string * 3)

private_print3("Hello ") # output: Hello Hello Hello

from print_thrice import private_print3
private_print3("Hello From Another File? ") # no output

This is probably not a perfect solution, as you can still "see" and/or "call" the method. Regardless, it doesn't execute.

Make button width fit to the text

If you are developing to a modern browser.

You can use:

width: fit-content;

Why in C++ do we use DWORD rather than unsigned int?

SDK developers prefer to define their own types using typedef. This allows changing underlying types only in one place, without changing all client code. It is important to follow this convention. DWORD is unlikely to be changed, but types like DWORD_PTR are different on different platforms, like Win32 and x64. So, if some function has DWORD parameter, use DWORD and not unsigned int, and your code will be compiled in all future windows headers versions.

AWS CLI S3 A client error (403) occurred when calling the HeadObject operation: Forbidden

I got this error with a mis-configured test event. I changed the source buckets ARN but forgot to edit the default S3 bucket name.

I.e. make sure that in the bucket section of the test event both the ARN and bucket name are set correctly:

"bucket": {
  "arn": "arn:aws:s3:::your_bucket_name",
  "name": "your_bucket_name",
  "ownerIdentity": {
    "principalId": "EXAMPLE"

How to Set Opacity (Alpha) for View in Android

Much more easier from the above. Default alpha attribute is there for button


The range is between 0 for complete transparent and 1 for complete opacity.

Convert javascript array to string

If value is associative array, such code will work fine:

var value = { "aaa": "111", "bbb": "222", "ccc": "333" };_x000D_
var blkstr = [];_x000D_
$.each(value, function(idx2,val2) {                    _x000D_
  var str = idx2 + ":" + val2;_x000D_
console.log(blkstr.join(", "));
<script src=""></script>

(output will appear in the dev console)

As Felix mentioned, each() is just iterating the array, nothing more.

Value of type 'T' cannot be converted to

I know similar code that the OP posted in this question from generic parsers. From a performance perspective, you should use Unsafe.As<TFrom, TResult>(ref TFrom source), which can be found in the System.Runtime.CompilerServices.Unsafe NuGet package. It avoids boxing for value types in these scenarios. I also think that Unsafe.As results in less machine code produced by the JIT than casting twice (using (TResult) (object) actualString), but I haven't checked that out.

public TResult ParseSomething<TResult>(ParseContext context)
    if (typeof(TResult) == typeof(string))
        var token = context.ParseNextToken();
        string parsedString = token.ParseToDotnetString();
        return Unsafe.As<string, TResult>(ref parsedString);
    else if (typeof(TResult) == typeof(int))
        var token = context.ParseNextToken();
        int parsedInt32 = token.ParseToDotnetInt32();
        // This will not box which might be critical to performance
        return Unsafe.As<int, TResult>(ref parsedInt32); 
    // other cases omitted for brevity's sake

Unsafe.As will be replaced by the JIT with efficient machine code instructions, as you can see in the official CoreFX repo:

Source Code of Unsafe.As

Locking pattern for proper use of .NET MemoryCache

Somewhat dated question, but maybe still useful: you may take a look at FusionCache ?, which I recently released.

The feature you are looking for is described here, and you can use it like this:

const string CacheKey = "CacheKey";
static string GetCachedData()
    return fusionCache.GetOrSet(
        _ => SomeHeavyAndExpensiveCalculation(),

You may also find some of the other features interesting like fail-safe, advanced timeouts with background factory completion and support for an optional, distributed 2nd level cache.

If you will give it a chance please let me know what you think.


Angular2 use [(ngModel)] with [ngModelOptions]="{standalone: true}" to link to a reference to model's property

Using @angular/forms when you use a <form> tag it automatically creates a FormGroup.

For every contained ngModel tagged <input> it will create a FormControl and add it into the FormGroup created above; this FormControl will be named into the FormGroup using attribute name.


<form #f="ngForm">
    <input type="text" [(ngModel)]="firstFieldVariable" name="firstField">
    <span>{{ f.controls['firstField']?.value }}</span>

Said this, the answer to your question follows.

When you mark it as standalone: true this will not happen (it will not be added to the FormGroup).


How can I set the font-family & font-size inside of a div?

You need a semicolon after font-family: Arial, Helvetica, sans-serif. This will make your updated code the following:

        <title>DIV Font</title>

                font-family:    Arial, Helvetica, sans-serif;
                font-size:      40px;
                font-weight:    bold;

        <div class="my_text">some text</div>

java : non-static variable cannot be referenced from a static context Error

You probably want to add "static" to the declaration of con2.

In Java, things (both variables and methods) can be properties of the class (which means they're shared by all objects of that type), or they can be properties of the object (a different one in each object of the same class). The keyword "static" is used to indicate that something is a property of the class.

"Static" stuff exists all the time. The other stuff only exists after you've created an object, and even then each individual object has its own copy of the thing. And the flip side of this is key in this case: static stuff can't access non-static stuff, because it doesn't know which object to look in. If you pass it an object reference, it can do stuff like "thingie.con2", but simply saying "con2" is not allowed, because you haven't said which object's con2 is meant.

MySQL : transaction within a stored procedure

Take a look at

Basically you declare error handler which will call rollback



Copy Paste in Bash on Ubuntu on Windows

Edit / Paste from the title bar's context menu (until they fix the control key shortcuts)

Delete all items from a c++ std::vector

If you keep pointers in container and don't want to bother with manually destroying of them, then use boost shared_ptr. Here is sample for std::vector, but you can use it for any other STL container (set, map, queue, ...)

#include <iostream>
#include <vector>
#include <boost/shared_ptr.hpp>

struct foo
    foo( const int i_x ) : d_x( i_x )
        std::cout << "foo::foo " << d_x << std::endl;

        std::cout << "foo::~foo " << d_x << std::endl;

    int d_x;

typedef boost::shared_ptr< foo > smart_foo_t;

int main()
    std::vector< smart_foo_t > foos;
    for ( int i = 0; i < 10; ++i )
        smart_foo_t f( new foo( i ) );
        foos.push_back( f );


    return 0;

How to import and export components using React + ES6 + webpack?

There are two different ways of importing components in react and the recommended way is component way

  1. Library way(not recommended)
  2. Component way(recommended)

PFB detail explanation

Library way of importing

import { Button } from 'react-bootstrap';
import { FlatButton } from 'material-ui';

This is nice and handy but it does not only bundles Button and FlatButton (and their dependencies) but the whole libraries.

Component way of importing

One way to alleviate it is to try to only import or require what is needed, lets say the component way. Using the same example:

import Button from 'react-bootstrap/lib/Button';
import FlatButton from 'material-ui/lib/flat-button';

This will only bundle Button, FlatButton and their respective dependencies. But not the whole library. So I would try to get rid of all your library imports and use the component way instead.

If you are not using lot of components then it should reduce considerably the size of your bundled file.

Android: How to turn screen on and off programmatically?

The best way to do it ( using rooted devices) :

protected void onCreate(Bundle savedInstanceState) {

    int flags = WindowManager.LayoutParams.FLAG_DISMISS_KEYGUARD | WindowManager.LayoutParams.FLAG_SHOW_WHEN_LOCKED | WindowManager.LayoutParams.FLAG_TURN_SCREEN_ON;
    getWindow().addFlags(flags); // this is how your app will wake up the screen
    //you will call this activity later


Now we have this two functions:

private void turnOffScreen(){

     Class c = Class.forName("android.os.PowerManager");
     PowerManager  mPowerManager = (PowerManager) this.getSystemService(Context.POWER_SERVICE);
     for(Method m : c.getDeclaredMethods()){
          if(m.getParameterTypes().length == 1){
  } catch (Exception e){

And this:

public void turnOnScreen(){
  Intent i = new Intent(this,YOURACTIVITYWITHFLAGS.class);

Sorry for my bad english.

Select arrow style change

It's working in all browser:

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


XPath with multiple conditions

You can apply multiple conditions in xpath using and, or

//input[@class='_2zrpKA _1dBPDZ' and @type='text']

//input[@class='_2zrpKA _1dBPDZ' or @type='text']

How to use OAuth2RestTemplate?

My simple solution. IMHO it's the cleanest.

First create a application.yml

spring.main.allow-bean-definition-overriding: true

      clientId: XXX
      clientSecret: XXX
      accessTokenUri: XXX
      tokenName: access_token
      grant-type: client_credentials

Create the main class: Main

public class Main extends WebSecurityConfigurerAdapter {

    protected void configure(HttpSecurity http) throws Exception {

    public static void main(String[] args) {, args);

    public OAuth2RestTemplate oauth2RestTemplate(ClientCredentialsResourceDetails details) {
        return new OAuth2RestTemplate(details);


Then Create the controller class: Controller

class OfferController {

    private OAuth2RestOperations restOperations;

    @RequestMapping(value = "/<your url>"
            , method = RequestMethod.GET
            , produces = "application/json")
    public String foo() {
        ResponseEntity<String> responseEntity = restOperations.getForEntity(<the url you want to call on the server>, String.class);
        return responseEntity.getBody();

Maven dependencies


Turn off auto formatting in Visual Studio

In addition to Tango's answer for the actual solution, there may be people actually want to stay current with auto-formats but not have it screw up your relevant changes. I would suggest that you modify the file to have auto-format activate, check in those changes, then proceed with the actual changes you wish to make.

That way your code can stay up to date, but your check in will be relevant.

Performance of Java matrix math libraries?

You may want to check out the jblas project. It's a relatively new Java library that uses BLAS, LAPACK and ATLAS for high-performance matrix operations.

The developer has posted some benchmarks in which jblas comes off favourably against MTJ and Colt.

How can I use "." as the delimiter with String.split() in java

The argument to split is a regular expression. The period is a regular expression metacharacter that matches anything, thus every character in line is considered to be a split character, and is thrown away, and all of the empty strings between them are thrown away (because they're empty strings). The result is that you have nothing left.

If you escape the period (by adding an escaped backslash before it), then you can match literal periods. (line.split("\\."))

How to execute a Windows command on a remote PC?

psexec \\RemoteComputer cmd.exe

or use ssh or TeamViewer or RemoteDesktop!

OSError [Errno 22] invalid argument when use open() in Python

In my case,the problem exists beacause I have not set permission for drive "C:\" and when I change my path to other drive like "F:\" my problem resolved.

Java NoSuchAlgorithmException - SunJSSE,$DefaultSSLContext

I've had a similar issue with this error. In my case, I was entering the incorrect password for the Keystore.

I changed the password for the Keystore to match what I was entering (I didn't want to change the password I was entering), but it still gave the same error.

keytool -storepasswd -keystore keystore.jks

Problem was that I also needed to change the Key's password within the Keystore.

When I initially created the Keystore, the Key was created with the same password as the Keystore (I accepted this default option). So I had to also change the Key's password as follows:

keytool -keypasswd  -alias my.alias -keystore keystore.jks

Reading column names alone in a csv file

import pandas as pd
data = pd.read_csv("data.csv")
cols = data.columns

How do I resolve "Run-time error '429': ActiveX component can't create object"?

You say it works once you install the VB6 IDE so the problem is likely to be that the components you are trying to use depend on the VB6 runtime being installed.

The VB6 runtime isn't installed on Windows by default.

Installing the IDE is one way to get the runtime. For non-developer machines, a "redistributable" installer package from Microsoft should be used instead.

Here is one VB6 runtime installer from Microsoft. I'm not sure if it will be the right version for your components:

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

git rm --cached file

should do what you want.

You can read more details at git help rm

Delete directory with files in it?

The Best Solution for me



function my_folder_delete($path) {
    if(!empty($path) && is_dir($path) ){
        $dir  = new RecursiveDirectoryIterator($path, RecursiveDirectoryIterator::SKIP_DOTS); //upper dirs are not included,otherwise DISASTER HAPPENS :)
        $files = new RecursiveIteratorIterator($dir, RecursiveIteratorIterator::CHILD_FIRST);
        foreach ($files as $f) {if (is_file($f)) {unlink($f);} else {$empty_dirs[] = $f;} } if (!empty($empty_dirs)) {foreach ($empty_dirs as $eachDir) {rmdir($eachDir);}} rmdir($path);

dont pass EMPTY VALUES to any Directory deleting functions!!! (backup them always, otherwise one day you might get DISASTER!!)

What is the best open-source java charting library? (other than jfreechart)

For dynamic 2D charts, I have been using JChart2D. It's fast, simple, and being updated regularly. The author has been quick to respond to my one bug report and few feature requests. We, at our company, prefer it over JFreeChart because it was designed for dynamic use, unlike JFreeChart.

How to make a view with rounded corners?

public class RoundedCornerLayout extends FrameLayout {
    private double mCornerRadius;

    public RoundedCornerLayout(Context context) {
        this(context, null, 0);

    public RoundedCornerLayout(Context context, AttributeSet attrs) {
        this(context, attrs, 0);

    public RoundedCornerLayout(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        init(context, attrs, defStyle);

    private void init(Context context, AttributeSet attrs, int defStyle) {
        DisplayMetrics metrics = context.getResources().getDisplayMetrics();
        setLayerType(View.LAYER_TYPE_SOFTWARE, null);

    public double getCornerRadius() {
        return mCornerRadius;

    public void setCornerRadius(double cornerRadius) {
        mCornerRadius = cornerRadius;

    public void draw(Canvas canvas) {
        int count =;

        final Path path = new Path();
        path.addRoundRect(new RectF(0, 0, canvas.getWidth(), canvas.getHeight()), (float) mCornerRadius, (float) mCornerRadius, Path.Direction.CW);
        canvas.clipPath(path, Region.Op.REPLACE);


Calling other function in the same controller?

To call a function inside a same controller in any laravel version follow as bellow

$role = $this->sendRequest('parameter');
// sendRequest is a public function

Is bool a native C type?

bool exists in the current C - C99, but not in C89/90.

In C99 the native type is actually called _Bool, while bool is a standard library macro defined in stdbool.h (which expectedly resolves to _Bool). Objects of type _Bool hold either 0 or 1, while true and false are also macros from stdbool.h.

Note, BTW, that this implies that C preprocessor will interpret #if true as #if 0 unless stdbool.h is included. Meanwhile, C++ preprocessor is required to natively recognize true as a language literal.

Scroll to a specific Element Using html

By using an href attribute inside an anchor tag you can scroll the page to a specific element using a # in front of the elements id name.

Also, here is some jQuery/JS that will accomplish putting variables into a div.


Click <a href="#myContent">here</a> to scroll to the myContent section.

<div id="myContent">

    var myClassName = "foo";

    $(function() {


How to ORDER BY a SUM() in MySQL?

This is how you do it


The SUM function will add up all rows, so the order by clause is useless, instead you will have to use the group by clause.

One command to create a directory and file inside it linux command

mkdir -p Python/Beginner/CH01 && touch $_/

Explanation: -p -> use -p if you wanna create parent and child directories $_ -> use it for current directory we work with it inline

How I can get and use the header file <graphics.h> in my C++ program?

<graphics.h> is not a standard header. Most commonly it refers to the header for Borland's BGI API for DOS and is antiquated at best.

However it is nicely simple; there is a Win32 implementation of the BGI interface called WinBGIm. It is implemented using Win32 GDI calls - the lowest level Windows graphics interface. As it is provided as source code, it is perhaps a simple way of understanding how GDI works.

WinBGIm however is by no means cross-platform. If all you want are simple graphics primitives, most of the higher level GUI libraries such as wxWidgets and Qt support that too. There are simpler libraries suggested in the possible duplicate answers mentioned in the comments.

Disable form auto submit on button click

<button>'s are in fact submit buttons, they have no other main functionality. You will have to set the type to button.
But if you bind your event handler like below, you target all buttons and do not have to do it manually for each button!

$('form button').on("click",function(e){

Error when using scp command "bash: scp: command not found"

Make sure the scp command is available on both sides - both on the client and on the server.

If this is Fedora or Red Hat Enterprise Linux and clones (CentOS), make sure this package is installed:

    yum -y install openssh-clients

If you work with Debian or Ubuntu and clones, install this package:

    apt-get install openssh-client

Again, you need to do this both on the server and the client, otherwise you can encounter "weird" error messages on your client: scp: command not found or similar although you have it locally. This already confused thousands of people, I guess :)

What command shows all of the topics and offsets of partitions in Kafka?

If anyone is interested, you can have the the offset information for all the consumer groups with the following command:

kafka-consumer-groups --bootstrap-server localhost:9092 --all-groups --describe

The parameter --all-groups is available from Kafka 2.4.0

Running Java gives "Error: could not open `C:\Program Files\Java\jre6\lib\amd64\jvm.cfg'"

If you have downloaded several Jdks you have to delete all except of the JDK you want to use!

Where is android studio building my .apk file?

Take a look at this question.

TL;DR: clean, then build.

./gradlew clean packageDebug 

How do you enable auto-complete functionality in Visual Studio C++ express edition?

  • Goto => Tools >> Options >> Text Editor >> C/C++ >> Advanced >> IntelliSense
  • Change => Member List Commit Aggressive to True

getting " (1) no such column: _id10 " error

I think you missed a equal sign at:

Cursor c = ourDatabase.query(DATABASE_TABLE, column, KEY_ROWID + "" + l, null, null, null, null);  

Change to:

Cursor c = ourDatabase.query(DATABASE_TABLE, column, KEY_ROWID + " = " + l, null, null, null, null); 

How to add/subtract time (hours, minutes, etc.) from a Pandas DataFrame.Index whos objects are of type datetime.time?

This one worked for me:

>> print(df)
                          TotalVolume  Symbol
2016-04-15 09:00:00       108400       2802.T
2016-04-15 09:05:00       50300        2802.T

>> print(df.set_index(pd.to_datetime(df.index.values) - datetime(2016, 4, 15)))

             TotalVolume  Symbol
09:00:00     108400       2802.T
09:05:00     50300        2802.T

expected constructor, destructor, or type conversion before ‘(’ token

The first constructor in the header should not end with a semicolon. #include <string> is missing in the header. string is not qualified with std:: in the .cpp file. Those are all simple syntax errors. More importantly: you are not using references, when you should. Also the way you use the ifstream is broken. I suggest learning C++ before trying to use it.

Let's fix this up:

# if !defined(__POLYGONE_H__)
# define __POLYGONE_H__

#include <iostream>
#include <string>    

class Polygone {
  // declarations have to end with a semicolon, definitions do not
  Polygone(){} // why would we needs this?
  Polygone(const std::string& fichier);

# endif


// no need to include things twice
#include "polygone.h"
#include <fstream>

Polygone::Polygone(const std::string& nom)
  std::ifstream fichier (nom, ios::in);

  if (fichier.is_open())
    // keep the scope as tiny as possible
    std::string line;
    // getline returns the stream and streams convert to booleans
    while ( std::getline(fichier, line) )
      std::cout << line << std::endl;
    std::cerr << "Erreur a l'ouverture du fichier" << std::endl;

android: how to change layout on button click?

First I would suggest putting a Log in each case of your switch to be sure that your code is being called.

Then I would check that the layouts are actually different.

Getting first and last day of the current month

An alternative way is to use DateTime.DaysInMonth to get the number of days in the current month as suggested by @Jade

Since we know the first day of the month will always 1 we can use it as default for the first day with the current Month & year as current.year,current.Month,1.

var now = DateTime.Now; // get the current DateTime 

//Get the number of days in the current month
int daysInMonth = DateTime.DaysInMonth (now.Year, now.Month); 
//First day of the month is always 1
var firstDay = new DateTime(now.Year,now.Month,1); 
//Last day will be similar to the number of days calculated above
var lastDay = new DateTime(now.Year,now.Month,daysInMonth);

rdpStartDate.SelectedDate = firstDay;
rdpEndDate.SelectedDate = lastDay; 

Download old version of package with NuGet

By using the Nuget Package Manager UI as mentioned above it helps to uninstall the nuget package first. I always have problems when going back on a nuget package version if I don't uninstall first. Some references are not cleaned properly. So I suggest the following workflow when installing an old nuget package through the Nuget Package Manager:

  1. Selected your nuget server / source
  2. Find and select the nuget package your want to install an older version
  3. Uninstall current version
  4. Click on the install drop-down > Select older version > Click Install

enter image description here

Good Luck :)

ORA-12154: TNS:could not resolve the connect identifier specified (PLSQL Developer)

For me it was bad formatting of the tnsnames.ora connect identifier. The indentation of the identifier string is required as shown in the tnsnames.ora example in the comment.

Open Facebook Page in Facebook App (if installed) on Android

you can use this:

try {
                Intent followIntent = new Intent(Intent.ACTION_VIEW, Uri.parse("fb://facewebmodal/f?href=" +
                        ""+scoped user id+"/"));
            } catch (Exception e) {
                activity.startActivity(new Intent(Intent.ACTION_VIEW, Uri.parse("" + user name)));
                String errorMessage = (e.getMessage() == null) ? "Message is empty" : e.getMessage();

attention: you can get scoped user id from "link" permission facebook api

Securely storing passwords for use in python script

I typically have a that is stored separately from my other python scripts and is not under version control. Then whenever required, you can do from secrets import <required_pwd_var>. This way you can rely on the operating systems in-built file security system without re-inventing your own.

Using Base64 encoding/decoding is also another way to obfuscate the password though not completely secure

More here - Hiding a password in a python script (insecure obfuscation only)

C++ Cout & Cin & System "Ambiguous"

This kind of thing doesn't just magically happen on its own; you changed something! In industry we use version control to make regular savepoints, so when something goes wrong we can trace back the specific changes we made that resulted in that problem.

Since you haven't done that here, we can only really guess. In Visual Studio, Intellisense (the technology that gives you auto-complete dropdowns and those squiggly red lines) works separately from the actual C++ compiler under the bonnet, and sometimes gets things a bit wrong.

In this case I'd ask why you're including both cstdlib and stdlib.h; you should only use one of them, and I recommend the former. They are basically the same header, a C header, but cstdlib puts them in the namespace std in order to "C++-ise" them. In theory, including both wouldn't conflict but, well, this is Microsoft we're talking about. Their C++ toolchain sometimes leaves something to be desired. Any time the Intellisense disagrees with the compiler has to be considered a bug, whichever way you look at it!

Anyway, your use of using namespace std (which I would recommend against, in future) means that std::system from cstdlib now conflicts with system from stdlib.h. I can't explain what's going on with std::cout and std::cin.

Try removing #include <stdlib.h> and see what happens.

If your program is building successfully then you don't need to worry too much about this, but I can imagine the false positives being annoying when you're working in your IDE.

:after and :before pseudo-element selectors in Sass

Use ampersand to specify the parent selector.

SCSS syntax:

p {
    margin: 2em auto;

    > a {
        color: red;

    &:before {
        content: "";

    &:after {
        content: "* * *";

Python argparse: default value or specified value

Actually, you only need to use the default argument to add_argument as in this script:

import argparse

if __name__ == '__main__':

    parser = argparse.ArgumentParser()
    parser.add_argument('--example', default=1)
    args = parser.parse_args()
    print(args.example) --example
% 1 --example 2
% 2

Details are here.

FIX CSS <!--[if lt IE 8]> in IE

How about

<!--[if IE]>

You can read here about conditional comments.

Get MAC address using shell script

This was the only thing that worked for me on Armbian:

dmesg | grep -oE 'mac=.*\w+' | cut -b '5-'

Nodejs - Redirect url

You have to use the following code:

response.writeHead(302 , {
           'Location' : '/view/index.html' // This is your url which you want

How to exit git log or git diff

The END comes from the pager used to display the log (your are at that moment still inside it). Type q to exit it.

Why are the Level.FINE logging messages not showing?

I found my actual problem and it was not mentioned in any answer: some of my unit-tests were causing logging initialization code to be run multiple times within the same test suite, messing up the logging on the later tests.

How to format a number as percentage in R?

Check out the scales package. It used to be a part of ggplot2, I think.

percent((1:10) / 100)
#  [1] "1%"  "2%"  "3%"  "4%"  "5%"  "6%"  "7%"  "8%"  "9%"  "10%"

The built-in logic for detecting the precision should work well enough for most cases.

percent((1:10) / 1000)
#  [1] "0.1%" "0.2%" "0.3%" "0.4%" "0.5%" "0.6%" "0.7%" "0.8%" "0.9%" "1.0%"
percent((1:10) / 100000)
#  [1] "0.001%" "0.002%" "0.003%" "0.004%" "0.005%" "0.006%" "0.007%" "0.008%"
#  [9] "0.009%" "0.010%"
percent(sqrt(seq(0, 1, by=0.1)))
#  [1] "0%"   "32%"  "45%"  "55%"  "63%"  "71%"  "77%"  "84%"  "89%"  "95%" 
# [11] "100%"
percent(seq(0, 0.1, by=0.01) ** 2)
#  [1] "0.00%" "0.01%" "0.04%" "0.09%" "0.16%" "0.25%" "0.36%" "0.49%" "0.64%"
# [10] "0.81%" "1.00%"

Codeigniter : calling a method of one controller from other

Controller to be extended

require_once(PHYSICAL_BASE_URL . 'system/application/controllers/abc.php');

        $report= new onlineAssessmentReport();
        echo ($report->detailView());

python pip: force install ignoring dependencies

pip has a --no-dependencies switch. You should use that.

For more information, run pip install -h, where you'll see this line:

--no-deps, --no-dependencies
                        Ignore package dependencies

How can I send and receive WebSocket messages on the server side?

In addition to the PHP frame encoding function, here follows a decode function:

function Decode($M){
    $M = array_map("ord", str_split($M));
    $L = $M[1] AND 127;

    if ($L == 126)
        $iFM = 4;
    else if ($L == 127)
        $iFM = 10;
        $iFM = 2;

    $Masks = array_slice($M, $iFM, 4);

    $Out = "";
    for ($i = $iFM + 4, $j = 0; $i < count($M); $i++, $j++ ) {
        $Out .= chr($M[$i] ^ $Masks[$j % 4]);
    return $Out;

I've implemented this and also other functions in an easy-to-use WebSocket PHP class here.

What's the difference between getRequestURI and getPathInfo methods in HttpServletRequest?

getPathInfo() gives the extra path information after the URI, used to access your Servlet, where as getRequestURI() gives the complete URI.

I would have thought they would be different, given a Servlet must be configured with its own URI pattern in the first place; I don't think I've ever served a Servlet from root (/).

For example if Servlet 'Foo' is mapped to URI '/foo' then I would have thought the URI:


Would result in:

RequestURI = /foo/path/to/resource


PathInfo = /path/to/resource

How do I autoindent in Netbeans?

Ctrl+Shift+F will do a format of all the code in the page.

Binding an Image in WPF MVVM

If you have a process that already generates and returns an Image type, you can alter the bind and not have to modify any additional image creation code.

Refer to the ".Source" of the image in the binding statement.


<Image Name="imgOpenClose" Source="{Binding ImageOpenClose.Source}"/>

View Model Field

private Image _imageOpenClose;
public Image ImageOpenClose
        return _imageOpenClose;
        _imageOpenClose = value;

How can I filter a date of a DateTimeField in Django?

Hm.. My solution is working:

Mymodel.objects.filter(date_time_field__startswith=datetime.datetime(1986, 7, 28))

Making button go full-width?

Why not use the Bootstrap predefined class input-block-level that does the job?

<a href="#" class="btn input-block-level">Full-Width Button</a> <!-- BS2 -->
<a href="#" class="btn form-control">Full-Width Button</a> <!-- BS3 -->

<!-- And let's join both for BS# :) -->
<a href="#" class="btn input-block-level form-control">Full-Width Button</a>

Learn more here in the Control Sizing^ section.

How do you remove a specific revision in the git history?

I also landed in a similar situation. Use interactive rebase using the command below and while selecting, drop 3rd commit.

git rebase -i remote/branch

Swift - how to make custom header for UITableView?

If you are using custom cell as header, add the following.

func tableView(_ tableView: UITableView, viewForHeaderInSection section: Int) -> UIView? {

        let headerView = UIView()
        let headerCell = tableView.dequeueReusableCell(withIdentifier: "customTableCell") as! CustomTableCell
        return headerView

If you want to have simple view, add the following.

func tableView(_ tableView: UITableView, viewForHeaderInSection section: Int) -> UIView? {
let headerView:UIView =  UIView()
    return headerView

How can I indent multiple lines in Xcode?

Basically ? [ for left multiple indent and ? ] right multiple indent.

For TR keyboard you can left multiple indent with ? ? 8 and right multiple indent with ? ? 9.Because both 8 and 9 are ALT characters of the these nums.Or if you have a keyboard which has [ or ] characters are belong to ALT(?) property so you can use ? ? KEYBOARD CHARACTER

CSS3 equivalent to jQuery slideUp and slideDown?

    try this for slide up slide down with animation 
give your **height

        @keyframes slide_up{
                min-height: 0;
                height: 0px;
                opacity: 0;
                height: 560px;
                opacity: 1;

        @keyframes slide_down{
                height: 560px;
                opacity: 1;
                min-height: 0;
                height: 0px;
                opacity: 0;

Is there any publicly accessible JSON data source to test with real world data?

Twitter has a public API which returns JSON, for example -

A GET request to:,

EDIT: Removed due to twitter restricting their API with OAUTH requirements...

{"errors": [{"message": "The Twitter REST API v1 is no longer active. Please migrate to API v1.1.", "code": 68}]}

Replacing it with a simple example of the Github API - that returns a tree, of in this case, my repositories...

I won't include the output, as it's long.. (returns 30 repos at a time) ... But here is proof of it's tree-ed-ness.

enter image description here

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

Xcode 5.1 no longer provides command line tools in the Preferences section. You now go to, and select the command line tools version for your OS X release. The installer puts them in /usr/bin.

How to set HttpResponse timeout for Android in Java

In my example, two timeouts are set. The connection timeout throws Socket is not connected and the socket timeout The operation timed out.

HttpGet httpGet = new HttpGet(url);
HttpParams httpParameters = new BasicHttpParams();
// Set the timeout in milliseconds until a connection is established.
// The default value is zero, that means the timeout is not used. 
int timeoutConnection = 3000;
HttpConnectionParams.setConnectionTimeout(httpParameters, timeoutConnection);
// Set the default socket timeout (SO_TIMEOUT) 
// in milliseconds which is the timeout for waiting for data.
int timeoutSocket = 5000;
HttpConnectionParams.setSoTimeout(httpParameters, timeoutSocket);

DefaultHttpClient httpClient = new DefaultHttpClient(httpParameters);
HttpResponse response = httpClient.execute(httpGet);

If you want to set the Parameters of any existing HTTPClient (e.g. DefaultHttpClient or AndroidHttpClient) you can use the function setParams().


How to insert data into elasticsearch

Simple fundamentals, Elastic community has exposed indexing, searching, deleting operation as rest web service. You can interact elastic using curl or sense(chrome plugin) or any rest client like postman.

If you are just testing few commands, I would recommend can use of sense chrome plugin which has simple UI and pretty mature plugin now.

Docker: unable to prepare context: unable to evaluate symlinks in Dockerfile path: GetFileAttributesEx

I had named my file dockerfile instead of Dockerfile (capitalized), and once I changed that, it started processing my "Dockerfile".

Error:Unknown host You may need to adjust the proxy settings in Gradle

make sure that you disable the proxy setting. settting > apperance and behaviour > Http Proxy > and select no proxy check box and check the connection after you select no proxy or auto detect proxy setting > the apply ok

Remove sensitive files and their commits from Git history

You can use git forget-blob.

The usage is pretty simple git forget-blob file-to-forget. You can get more info here

It will disappear from all the commits in your history, reflog, tags and so on

I run into the same problem every now and then, and everytime I have to come back to this post and others, that's why I automated the process.

Credits to contributors from Stack Overflow that allowed me to put this together

java Compare two dates

You equals(Object o) comparison is correct.

Yet, you should use after(Date d) and before(Date d) for date comparison.

How can I change the size of a Bootstrap checkbox?

It is possible in css, but not for all the browsers.

The effect on all browsers:

A possibility is a custom checkbox with javascript:

Vagrant error : Failed to mount folders in Linux guest

I believe this is the most updated answer now and it worked for me ( Guest Additions Version: 5.0.6, VirtualBox Version: 4.3.16, Ubuntu 14.04 LTS)

Basically i says:

Simple and Quick Solution for Failed to mount folders in Linux guest issue.

Add the following line to your Homestead/Vagrantfile:

config.vbguest.auto_update = false
Your Homestead/Vagrantfile should looks like this:


Vagrant.configure(VAGRANTFILE_API_VERSION) do |config|

   # To avoid install and uninstall VBoxGuessAdditions during vagrant provisioning.
    config.vbguest.auto_update = false

Save it and execute

$ vagrant destroy --force
$ vagrant up

Python datetime - setting fixed hour and minute after using strptime to get day,month,year

datetime.replace() will provide the best options. Also, it provides facility for replacing day, year, and month.

Suppose we have a datetime object and date is represented as: "2017-05-04"

>>> from datetime import datetime
>>> date = datetime.strptime('2017-05-04',"%Y-%m-%d")
>>> print(date)
2017-05-04 00:00:00
>>> date = date.replace(minute=59, hour=23, second=59, year=2018, month=6, day=1)
>>> print(date)
2018-06-01 23:59:59

How to determine total number of open/active connections in ms sql server 2005

If your PHP app is holding open many SQL Server connections, then, as you may know, you have a problem with your app's database code. It should be releasing/disposing those connections after use and using connection pooling. Have a look here for a decent article on the topic...

SQL Server Text type vs. varchar data type

If you're using SQL Server 2005 or later, use varchar(MAX). The text datatype is deprecated and should not be used for new development work. From the docs:


ntext , text, and image data types will be removed in a future version of Microsoft SQL Server. Avoid using these data types in new development work, and plan to modify applications that currently use them. Use nvarchar(max), varchar(max), and varbinary(max) instead.

How do I get my page title to have an icon?

They're called favicons, and are quite easy to make/use. Have a read of for help.

Calculate Pandas DataFrame Time Difference Between Two Columns in Hours and Minutes

This was driving me bonkers as the .astype() solution above didn't work for me. But I found another way. Haven't timed it or anything, but might work for others out there:

t1 = pd.to_datetime('1/1/2015 01:00')
t2 = pd.to_datetime('1/1/2015 03:30')

print pd.Timedelta(t2 - t1).seconds / 3600.0

...if you want hours. Or:

print pd.Timedelta(t2 - t1).seconds / 60.0

...if you want minutes.

How to get value of Radio Buttons?

For Win Forms :

To get the value (assuming that you want the value, not the text) out of a radio button, you get the Checked property:

string value = "";
bool isChecked = radioButton1.Checked;
if(isChecked )

For Web Forms :

<asp:RadioButtonList ID="rdoPriceRange" runat="server" RepeatLayout="Flow">
    <asp:ListItem Value="Male">Male</asp:ListItem>
    <asp:ListItem Value="Female">Female</asp:ListItem>

And CS-in some button click

string value=rdoPriceRange.SelectedItem.Value.ToString();

How do I force files to open in the browser instead of downloading (PDF)?

Just open Adobe Reader, menu ? Edit ? Preferences ? Internet, then change to browser mode or for detailed instructions on different browsers try Display PDF in browser | Acrobat, Acrobat Reader.

C# Parsing JSON array of objects

Though this is an old question, I thought I'd post my answer anyway, if that helps someone in future

 JArray array = JArray.Parse(jsonString);
 foreach (JObject obj in array.Children<JObject>())
     foreach (JProperty singleProp in obj.Properties())
         string name = singleProp.Name;
         string value = singleProp.Value.ToString();
         //Do something with name and value
         //System.Windows.MessageBox.Show("name is "+name+" and value is "+value);

This solution uses Newtonsoft library, don't forget to include using Newtonsoft.Json.Linq;

Spring configure @ResponseBody JSON format

In spring3.2, new solution is introduced by: , the below is my example:

     ??<bean class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">
       ???<property name="objectMapper">
           ?????<property name="featuresToEnable">
               ???????<util:constant static-field="com.fasterxml.jackson.core.JsonParser.Feature.ALLOW_SINGLE_QUOTES" />

How to align linearlayout to vertical center?

use android:layout_gravity instead of android:gravity

android:gravity sets the gravity of the content of the View its used on. android:layout_gravity sets the gravity of the View or Layout in its parent.

Join two sql queries

Try this:

select Activity, SUM(Incomes.Amount) as "Total Amount 2009", SUM(Incomes2008.Amount) 
as "Total Amount 2008" from
Activities, Incomes, Incomes2008
where Activities.UnitName = ?  AND
Incomes.ActivityId = Activities.ActivityID  AND
Incomes2008.ActivityId = Activities.ActivityID GROUP BY
Activity ORDER BY Activity;

Basically you have to JOIN Incomes2008 table with the output of your first query.

laravel throwing MethodNotAllowedHttpException

// not done
Route::post('`/posts/{id}`', 'PostsController@store')->name('');

return redirect('`/posts'`)->with('status','Post was created !');

// done
Route::post('`/posts`', 'PostsController@store')->name('');

return redirect('`/posts'`)->with('status','Post was created !');

removing html element styles via javascript

In JavaScript:

document.getElementById("id").style.display = null;

In jQuery:


How to get the date from the DatePicker widget in Android?

U can also use te Calendar.GregorianCalendar java class

    GregorianCalendar calendarBeg=new GregorianCalendar(datePicker.getYear(),
    Date begin=calendarBeg.getTime();

No Main class found in NetBeans

The connections I made in preparing this for posting really cleared it up for me, once and for all. It's not completely obvious what goes in the Main Class: box until you see the connections. (Note that the class containing the main method need not necessarily be named Main but the main method can have no other name.)

enter image description here

Round to 5 (or other number) in Python

In case someone needs "financial rounding" (0.5 rounds always up):

def myround(x, base=5):
    roundcontext = decimal.Context(rounding=decimal.ROUND_HALF_UP)
    return int(base *float(decimal.Decimal(x/base).quantize(decimal.Decimal('0'))))

As per documentation other rounding options are:

ROUND_CEILING (towards Infinity),
ROUND_DOWN (towards zero),
ROUND_FLOOR (towards -Infinity),
ROUND_HALF_DOWN (to nearest with ties going towards zero),
ROUND_HALF_EVEN (to nearest with ties going to nearest even integer),
ROUND_HALF_UP (to nearest with ties going away from zero), or
ROUND_UP (away from zero).
ROUND_05UP (away from zero if last digit after rounding towards zero would have been 0 or 5; otherwise towards zero)

By default Python uses ROUND_HALF_EVEN as it has some statistical advantages (the rounded results are not biased).

How do I delete all messages from a single queue using the CLI?

To purge queue you can use following command (more information in API doc):

curl -i -u guest:guest -XDELETE http://localhost:15672/api/queues/vhost_name/queue_name/contents

Recommendation for compressing JPG files with ImageMagick

I'm using the Google Pagespeed Insights image optimization guidelines, and for ImageMagick they recommend the following:

-sampling-factor 4:2:0
-quality 85 [it can vary, I use range 60-80, lower number here means smaller file]
-colorspace RGB

Command in ImageMagick:

convert image.jpg -sampling-factor 4:2:0 -strip -quality 85 -interlace JPEG -colorspace RGB image_converted.jpg

With these options I get up to 40% savings in JPEG size without much visible loss.

How to change checkbox's border style in CSS?

Here's my version that uses FontAwesome for checkbox ticker, I think FontAwesome is used by almost everybody so it's safe to assume you have it too. Not tested in IE/Edge and I don't think anyone cares.

input[type=checkbox] {_x000D_
 outline: none;_x000D_
 content: none; _x000D_
input[type=checkbox]:before {_x000D_
 font-family: "FontAwesome";_x000D_
    content: "\f00c";_x000D_
    font-size: 15px;_x000D_
    color: transparent !important;_x000D_
    background: #fef2e0;_x000D_
    display: block;_x000D_
    width: 15px;_x000D_
    height: 15px;_x000D_
    border: 1px solid black;_x000D_
    margin-right: 7px;_x000D_
input[type=checkbox]:checked:before {_x000D_
 color: black !important;_x000D_
<link href="" rel="stylesheet"/>_x000D_
<input type="checkbox">

How do I set up NSZombieEnabled in Xcode 4?

Cocoa offers a cool feature which greatly enhances your capabilities to debug such situations. It is an environment variable which is called NSZombieEnabled, watch this video that explains setting up NSZombieEnabled in objective-C

How to resolve "Server Error in '/' Application" error?

You may get this error when trying to browse an ASP.NET application.

The debug information shows that "This error can be caused by a virtual directory not being configured as an application in IIS."

However, this error occurs primarily out of two scenarios.

  1. When you create an new web application using Visual Studio .NET, it automatically creates the virtual directory and configures it as an application. However, if you manually create the virtual directory and it is not configured as an application, then you will not be able to browse the application and may get the above error. The debug information you get as mentioned above, is applicable to this scenario.

To resolve it, right click on the virtual directory - select properties and then click on "Create" next to the "Application" Label and the text box. It will automatically create the "application" using the virtual directory's name. Now the application can be accessed.

  1. When you have sub-directories in your application, you can have web.config file for the sub-directory. However, there are certain properties which cannot be set in the web.config of the sub-directory such as authentication, session state (you may see that the error message shows the line number where the authentication or session state is declared in the web.config of the sub-directory). The reason is, these settings cannot be overridden at the sub-directory level unless the sub-directory is also configured as an application (as mentioned in the above point).

Mostly, we have the practice of adding web.config in the sub-directory if we want to protect access to the sub-directory files (say, the directory is admin and we wish to protect the admin pages from unauthorized users).

The maximum message size quota for incoming messages (65536) has been exceeded

Updating the config didn't work for me, but I was able to edit the binding programmatically:

private YourAPIClient GetClient()
    Uri baseAddress = new Uri(APIURL);

    var binding = new BasicHttpBinding();
    binding.MaxReceivedMessageSize = 20000000;
    binding.MaxBufferSize = 20000000;
    binding.MaxBufferPoolSize = 20000000;
    binding.AllowCookies = true;

    var readerQuotas = new XmlDictionaryReaderQuotas();
    readerQuotas.MaxArrayLength = 20000000;
    readerQuotas.MaxStringContentLength = 20000000;
    readerQuotas.MaxDepth = 32;
    binding.ReaderQuotas = readerQuotas;

    if (baseAddress.Scheme.ToLower() == "https")
        binding.Security.Mode = BasicHttpSecurityMode.Transport;

    var client = new YourAPIClient(binding, new EndpointAddress(baseAddress));
    return client;

Android, How to limit width of TextView (and add three dots at the end of text)?

Add These two lines in your text


What are some good Python ORM solutions?

We use Elixir alongside SQLAlchemy and have liked it so far. Elixir puts a layer on top of SQLAlchemy that makes it look more like the "ActiveRecord pattern" counter parts.

New Line Issue when copying data from SQL Server 2012 to Excel

Instead of copying & pasting into excel you could export to Excel. Right click the database -> Tasks -> Export Data...

  • Source: SQL Server Native Client
  • Destination: Excel
  • Specify Table Copy or Query: pick query and enter your query

CR/LF retained in the data.

BONUS(nulls are not copied as 'NULL').

Run Button is Disabled in Android Studio

Above answer didn't work for me, just do click File -> Invalidate/cache -> Invalidate and Restart.

How to get the type of a variable in MATLAB?

MATLAB - Checking type of variables

class() exactly works like Javascript's typeof operator.

To get more details about variables you can use whos command or whos() function.

Here is the example code executed on MATLAB R2017a's Command Window.

>> % Define a number
>> num = 67

num =


>> % Get type of variable num
>> class(num)

ans =


>> % Define character vector
>> myName = 'Rishikesh Agrawani'

myName =

    'Rishikesh Agrwani'

>> % Check type of myName
>> class(myName)

ans =


>> % Define a cell array
>> cellArr = {'This ', 'is ', 'a ', 'big chance to learn ', 'MATLAB.'}; % Cell array
>> class(cellArr)

ans =


>> % Get more details including type
>> whos num
  Name      Size            Bytes  Class     Attributes

  num       1x1                 8  double              

>> whos myName
  Name        Size            Bytes  Class    Attributes

  myName      1x17               34  char               

>> whos cellArr
  Name         Size            Bytes  Class    Attributes

  cellArr      1x5               634  cell               

>> % Another way to use whos i.e using whos(char_vector)
>> whos('cellArr')
  Name         Size            Bytes  Class    Attributes

  cellArr      1x5               634  cell               

>> whos('num')
  Name      Size            Bytes  Class     Attributes

  num       1x1                 8  double              

>> whos('myName')
  Name        Size            Bytes  Class    Attributes

  myName      1x17               34  char               


need to add a class to an element

You can use result.className = 'red';, but you can also use result.classList.add('red');. The .classList.add(str) way is usually easier if you need to add a class in general, and don't want to check if the class is already in the list of classes.

How to output messages to the Eclipse console when developing for Android

i use below log format for print my content in logCat

Log.e("Msg","What you have to print");

Git:nothing added to commit but untracked files present

Follow all the steps.

Step 1: initialize git

$ git init

Step 2: Check files are exist or not.

$git ls

Step 3 : Add the file

$git add filename

Step 4: Add comment to show

$git commit -m "your comment"

Step 5: Link to your repository

$git remote add origin  "copy repository link  and paste here"

Step 6: Push on Git

$ git push -u origin master

Setting Custom ActionBar Title from Fragment

Just to add onto the selected answer, you may also want to add a second method to your main activity. So you would end up with the following methods in your main activity:

public void setActionBarTitle(String title) {

public void setActionBarTitle(int resourceId) {

This will allow you set the title from both a String variable as well as a resource ID such as from your strings.xml file. This will also work a little more like how getSupportActionBar().setTitle() works since it allows you to pass in a resource ID.

SSH Private Key Permissions using Git GUI or ssh-keygen are too open

What did the trick for me was to update CYGWIN environment variable with: "tty nodosfilewarning". Didn't even need to chmod the key.

Regex select all text between tags

Try this....


How to compile a 64-bit application using Visual C++ 2010 Express?

Note that Visual C++ compilers are removed when you upgrade Visual Studio 2010 Professional or Visual Studio 2010 Express to Visual Studio 2010 SP1 if Windows SDK v7.1 is installed.

For instructions on resolving this, see KB2519277 on the Microsoft Support site.

Get css top value as number not as string?

You can use the parseInt() function to convert the string to a number, e.g:


Update: (as suggested by Ben): You should give the radix too:

parseInt($('#elem').css('top'), 10);

Forces it to be parsed as a decimal number, otherwise strings beginning with '0' might be parsed as an octal number (might depend on the browser used).

How does one set up the Visual Studio Code compiler/debugger to GCC?

Ctrl+P and Type "ext install cpptools" it will install everything you need to debug c and c++.

Debugging in VS code is very complete, but if you just need to compile and run:

Look in the debugging section and it will explain everything

How can I get screen resolution in java?

int screenResolution = Toolkit.getDefaultToolkit().getScreenResolution();

When do I need to use Begin / End Blocks and the Go keyword in SQL Server?

GO ends a batch, you would only very rarely need to use it in code. Be aware that if you use it in a stored proc, no code after the GO will be executed when you execute the proc.

BEGIN and END are needed for any procedural type statements with multipe lines of code to process. You will need them for WHILE loops and cursors (which you will avoid if at all possible of course) and IF statements (well techincally you don't need them for an IF statment that only has one line of code, but it is easier to maintain the code if you always put them in after an IF). CASE statements also use an END but do not have a BEGIN.

What should I set JAVA_HOME environment variable on macOS X 10.6?

I've found this stack to help, i was having the same issue and i could fix:

My java path was here:

/Library/Internet Plug-Ins/JavaAppletPlugin.plugin/Contents/Home

and was needed to put into my .bash_profile:

export JAVA_HOME=\"/Library/Internet Plug-Ins/JavaAppletPlugin.plugin/Contents/Home\"

Hope help

Regex Named Groups in Java

(Update: August 2011)

As geofflane mentions in his answer, Java 7 now support named groups.
tchrist points out in the comment that the support is limited.
He details the limitations in his great answer "Java Regex Helper"

Java 7 regex named group support was presented back in September 2010 in Oracle's blog.

In the official release of Java 7, the constructs to support the named capturing group are:

  • (?<name>capturing text) to define a named group "name"
  • \k<name> to backreference a named group "name"
  • ${name} to reference to captured group in Matcher's replacement string
  • name) to return the captured input subsequence by the given "named group".

Other alternatives for pre-Java 7 were:

(Original answer: Jan 2009, with the next two links now broken)

You can not refer to named group, unless you code your own version of Regex...

That is precisely what Gorbush2 did in this thread.


(limited implementation, as pointed out again by tchrist, as it looks only for ASCII identifiers. tchrist details the limitation as:

only being able to have one named group per same name (which you don’t always have control over!) and not being able to use them for in-regex recursion.

Note: You can find true regex recursion examples in Perl and PCRE regexes, as mentioned in Regexp Power, PCRE specs and Matching Strings with Balanced Parentheses slide)



"TEST 123"


"(?<login>\\w+) (?<id>\\d+)"

Access ==> TEST"login") ==> TEST ==> login


matcher.replaceAll("aaaaa_$1_sssss_$2____") ==> aaaaa_TEST_sssss_123____
matcher.replaceAll("aaaaa_${login}_sssss_${id}____") ==> aaaaa_TEST_sssss_123____ 

(extract from the implementation)

public final class Pattern
     * Parses a group and returns the head node of a set of nodes that process
     * the group. Sometimes a double return system is used where the tail is
     * returned in root.
    private Node group0() {
        boolean capturingGroup = false;
        Node head = null;
        Node tail = null;
        int save = flags;
        root = null;
        int ch = next();
        if (ch == '?') {
            ch = skip();
            switch (ch) {

            case '<':   // (?<xxx)  look behind or group name
                ch = read();
                int start = cursor;
                // test forGroupName
                int startChar = ch;
                while(ASCII.isWord(ch) && ch != '>') ch=read();
                if(ch == '>'){
                    // valid group name
                    int len = cursor-start;
                    int[] newtemp = new int[2*(len) + 2];
                    //System.arraycopy(temp, start, newtemp, 0, len);
                    StringBuilder name = new StringBuilder();
                    for(int i = start; i< cursor; i++){
                    // create Named group
                    head = createGroup(false);
                    ((GroupTail)root).name = name.toString();

                    capturingGroup = true;
                    tail = root;
           = expr(tail);

How to determine an object's class?

You can use:

Object instance = new SomeClass();
instance.getClass().getName(); //will return the name (as String) (== "SomeClass")
instance.getClass(); //will return the SomeClass' Class object

HTH. But I think most of the time it is no good practice to use that for control flow or something similar...

Exception : mockito wanted but not invoked, Actually there were zero interactions with this mock

@Jk1's answer is fine, but Mockito also allows for more succinct injection using annotations:

@InjectMocks MyClass myClass; //@InjectMocks automatically instantiates too
@Mock MyInterface myInterface

But regardless of which method you use, the annotations are not being processed (not even your @Mock) unless you somehow call the static MockitoAnnotation.initMocks() or annotate the class with @RunWith(MockitoJUnitRunner.class).

Run C++ in command prompt - Windows

  1. Download MinGW form :
  2. use notepad++ to write the C++ source code.
  3. using command line change the directory/folder where the source code is saved(using notepad++)
  4. compile: g++ file_name.cpp -o file_name.exe
  5. run the executable: file_name.exe

Android background music service

way too late for the party here but i will still add my $0.02, Google has released a free sample called universal music player with which you can learn to stream music across all android platforms(auto, watch,mobile,tv..) it uses service to play music in the background, do check it out very helpful. here's the link to the project

AngularJs event to call after content is loaded

I was using {{myFunction()}} in the template but then found another way here using $timeout inside the controller. Thought I'd share it, works great for me.

angular.module('myApp').controller('myCtrl', ['$timeout',
function($timeout) {
var self = this;

self.controllerFunction = function () { alert('controller function');}

$timeout(function () {
    var vanillaFunction = function () { alert('vanilla function'); }();


How do I see active SQL Server connections?

Click the "activity monitor" icon in the toolbar.

From Thorsten's comment:

In SQL Server Management Studio, right click on Server, choose "Activity Monitor" from context menu -or- use keyboard shortcut Ctrl + Alt + A.

Reference: Microsoft Docs - Open Activity Monitor in SQL Server Management Studio (SSMS)

How to fill a datatable with List<T>

Try this

static DataTable ConvertToDatatable(List<Item> list)
    DataTable dt = new DataTable();

    foreach (var item in list)
        var row = dt.NewRow();

        row["Name"] = item.Name;
        row["Price"] = Convert.ToString(item.Price);
        row["URL"] = item.URL;


    return dt;

Inserting Data into Hive Table

You can use following lines of code to insert values into an already existing table. Here the table is db_name.table_name having two columns, and I am inserting 'All','done' as a row in the table.

insert into table db_name.table_name
select 'ALL','Done';

Hope this was helpful.

Hiding and Showing TabPages in tabControl

A different approach would be to have two tab controls, one visible, and one not. You can move the tabs from one to the other like this (

If Me.chkShowTab1.Checked = True Then
End If

If the tab order is important, change the .Add method on tabsShown to .Insert and specify the ordinal position. One way to do that is to call a routine that returns the desired ordinal position.

jQuery select by attribute using AND and OR operators

In your special case it would be


Conditional formatting, entire row based

Use the "indirect" function on conditional formatting.

  1. Select Conditional Formatting
  2. Select New Rule
  3. Select "Use a Formula to determine which cells to format"
  4. Enter the Formula, =INDIRECT("g"&ROW())="X"
  5. Enter the Format you want (text color, fill color, etc).
  6. Select OK to save the new format
  7. Open "Manage Rules" in Conditional Formatting
  8. Select "This Worksheet" if you can't see your new rule.
  9. In the "Applies to" box of your new rule, enter =$A$1:$Z$1500 (or however wide/long you want the conditional formatting to extend depending on your worksheet)

For every row in the G column that has an X, it will now turn to the format you specified. If there isn't an X in the column, the row won't be formatted.

You can repeat this to do multiple row formatting depending on a column value. Just change either the g column or x specific text in the formula and set different formats.

For example, if you add a new rule with the formula, =INDIRECT("h"&ROW())="CAR", then it will format every row that has CAR in the H Column as the format you specified.

Get single row result with Doctrine NativeQuery

I use fetchObject() here a small example using Symfony 4.4

    use Doctrine\DBAL\Driver\Connection;

    class MyController{

    public function index($username){
      $queryBuilder = $connection->createQueryBuilder();
        ->select('id', 'name')
        ->where('name = ?')
        ->setParameter(0, $username)
      $stmUser = $queryBuilder->execute();


      //get_class_methods($stmUser) -> to see all methods


"id": "2", "name":"myuser"

What is the difference between Serialization and Marshaling?

My vies is:

Problem: Object belongs to some process(VM) and it's lifetime is the same

Serialisation - transform object state into stream of bytes(JSON, XML...) for saving, sharing, transforming...

Marshalling - contains Serialisation + codebase. Usually it used by Remote procedure call(RPC) -> Java Remote Method Invocation(Java RMI) where you are able to invoke a object's method which is hosted on remote Java processes.

codebase - is a place or URL to class definition where it can be downloaded by ClassLoader. CLASSPATH[About] is as a local codebase

JVM -> Class Loader -> load class definition -> class

Very simple diagram for RMI

Serialisation - state
Marshalling - state + class definition

Official doc

Set transparent background using ImageMagick and commandline prompt

If you want to control the level of transparency you can use rgba. where a is the alpha. 0 for transparent and 1 for opaque. Make sure that final output file must have .png extension for transparency.

    -channel rgba 
    -fuzz 40% 
    -fill "rgba(255,255,255,0.5)" 
    -opaque "rgb(255,255,255)" 

Getting title and meta tags from external website

Improved answer from @shamittomar above to get the meta tags (or the specified one from html source)

Can be improved further... the difference from php's default get_meta_tags is that it works even when there is unicode string

function getMetaTags($html, $name = null)
    $doc = new DOMDocument();
    try {
    } catch (Exception $e) {


    $metas = $doc->getElementsByTagName('meta');

    $data = [];
    for ($i = 0; $i < $metas->length; $i++)
        $meta = $metas->item($i);

        if (!empty($meta->getAttribute('name'))) {
            // will ignore repeating meta tags !!
            $data[$meta->getAttribute('name')] = $meta->getAttribute('content');

    if (!empty($name)) {
        return !empty($data[$name]) ? $data[$name] : false;

    return $data;

Converting data frame column from character to numeric

If we need only one column to be numeric

yyz$b <- as.numeric(as.character(yyz$b))

But, if all the columns needs to changed to numeric, use lapply to loop over the columns and convert to numeric by first converting it to character class as the columns were factor.

yyz[] <- lapply(yyz, function(x) as.numeric(as.character(x)))

Both the columns in the OP's post are factor because of the string "n/a". This could be easily avoided while reading the file using na.strings = "n/a" in the read.table/read.csv or if we are using data.frame, we can have character columns with stringsAsFactors=FALSE (the default is stringsAsFactors=TRUE)

Regarding the usage of apply, it converts the dataset to matrix and matrix can hold only a single class. To check the class, we need

lapply(yyz, class)


sapply(yyz, class)

Or check


segmentation fault : 11

What system are you running on? Do you have access to some sort of debugger (gdb, visual studio's debugger, etc.)?

That would give us valuable information, like the line of code where the program crashes... Also, the amount of memory may be prohibitive.

Additionally, may I recommend that you replace the numeric limits by named definitions?

As such:

#define DIM1_SZ 1000
#define DIM2_SZ 1000000

Use those whenever you wish to refer to the array dimension limits. It will help avoid typing errors.

How can I get System variable value in Java?

Actually the variable can be set or not, so, In Java 8 or superior its nullable value should be wrapped into an Optional object, which allows really good features. In the following example we gonna try to obtain the variable ENV_VAR1, if it doesnt exist we may throw some custom Exception to alert about it:

String ENV_VAR1 = Optional.ofNullable(System.getenv("ENV_VAR1")).orElseThrow(
  () -> new CustomException("ENV_VAR1 is not set in the environment"));

What exactly does += do in python?

+= adds a number to a variable, changing the variable itself in the process (whereas + would not). Similar to this, there are the following that also modifies the variable:

  • -=, subtracts a value from variable, setting the variable to the result
  • *=, multiplies the variable and a value, making the outcome the variable
  • /=, divides the variable by the value, making the outcome the variable
  • %=, performs modulus on the variable, with the variable then being set to the result of it

There may be others. I am not a Python programmer.

Postgresql -bash: psql: command not found

In case you are running it on Fedora or CentOS, this is what worked for me (PostgreSQL 9.6):

In terminal:

$ sudo visudo -f /etc/sudoers

modify the following text from:

Defaults    secure_path = /sbin:/bin:/usr/sbin:/usr/bin


Defaults    secure_path = /sbin:/bin:/usr/sbin:/usr/bin:/usr/pgsql-9.6/bin

exit, then:

$ printenv PATH

$ sudo su postgres

$ psql

To exit postgreSQL terminal, you need to digit:

$ \q


Replace comma with newline in sed on MacOS?

MacOS is different, there is two way to solve this problem with sed in mac

  • first ,use \'$'\n'' replace \n, it can work in MacOS:

    sed 's/,/\'$'\n''/g' file
  • the second, just use an empty line:

    sed 's/,/\
    /g' file
  • Ps. Pay attention the range separated by '

  • the third, use gnu-sed replace the mac-sed

How to replace all occurrences of a string in Javascript?

Say you want to replace all the 'abc' with 'x':

let some_str = 'abc def def lom abc abc def'.split('abc').join('x')
console.log(some_str) //x def def lom x x def

I was trying to think about something more simple than modifying the string prototype.

Check if returned value is not null and if so assign it, in one line, with one method call

If you're not on java 1.8 yet and you don't mind to use commons-lang you can use org.apache.commons.lang3.ObjectUtils#defaultIfNull

Your code would be:

dinner = ObjectUtils.defaultIfNull(cage.getChicken(),getFreeRangeChicken())

Measuring Query Performance : "Execution Plan Query Cost" vs "Time Taken"

I understand it’s an old question – however I would like to add an example where cost is same but one query is better than the other.

As you observed in the question, % shown in execution plan is not the only yardstick for determining best query. In the following example, I have two queries doing the same task. Execution Plan shows both are equally good (50% each). Now I executed the queries with SET STATISTICS IO ON which shows clear differences.

In the following example, the query 1 uses seek whereas Query 2 uses scan on the table LWManifestOrderLineItems. When we actually checks the execution time however it is find that Query 2 works better.

Also read When is a Seek not a Seek? by Paul White





FROM LWManifestOrderLineItems LW
INNER JOIN ManifestContainers MC
    ON MC.Manifest = LW.Manifest
GROUP BY LW.Manifest,LW.OrderID

SELECT LW.Manifest,LW.OrderID,COUNT( LineItemID) LineCount
FROM LWManifestOrderLineItems LW
WHERE LW.Manifest IN (SELECT Manifest FROM ManifestContainers)
GROUP BY LW.Manifest,LW.OrderID

Statistics IO

enter image description here

Execution Plan

enter image description here

How to get SLF4J "Hello World" working with log4j?

you need to add 3 dependency ( API+ API implementation + log4j dependency) 
Add also this 

# And to see log in command line , set 

# Root logger option
log4j.rootLogger=INFO, file, stdout
log4j.appender.stdout.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss} %-5p %c{1}:%L - %m%n

#And to see log in file  , set 
# Direct log messages to a log file
log4j.appender.file.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss} %-5p %c{1}:%L - %m%n

Limiting the number of characters per line with CSS

Another approach to this would put a span element with a display:block style inside the p element each time you need the content to break. It would only be useful when your p content is static.

<p>this is a not-dynamic text and I want to put<span style="display:block">the following words in the next line</span>and these other words in a third one</p>

It would output:

This is a not-dynamic text and I want to put

the following words in the next line

and these others in a third one

This allows you to change your text line-breaks in different viewports without JS.

how to set ulimit / file descriptor on docker container the image tag is phusion/baseimage-docker

The docker run command has a --ulimit flag you can use this flag to set the open file limit in your docker container.

Run the following command when spinning up your container to set the open file limit.

docker run --ulimit nofile=<softlimit>:<hardlimit> the first value before the colon indicates the soft file limit and the value after the colon indicates the hard file limit. you can verify this by running your container in interactive mode and executing the following command in your containers shell ulimit -n

PS: check out this blog post for more clarity

Setting the number of map tasks and reduce tasks

In the newer version of Hadoop, there are much more granular and mapreduce.job.running.reduce.limit which allows you to set the mapper and reducer count irrespective of hdfs file split size. This is helpful if you are under constraint to not take up large resources in the cluster.


How do I use InputFilter to limit characters in an EditText in Android?

First add into strings.xml:

<string name="vin_code_mask">0123456789abcdefghjklmnprstuvwxyz</string>



Code in Kotlin:

edit_text.filters += InputFilter { source, start, end, _, _, _ ->
    val mask = getString(R.string.vin_code_mask)
    for (i in start until end) {
        if (!mask.contains(source[i])) {
            return@InputFilter ""

Strange, but it works weirdly on emulator's soft keyboard.

Warning! The following code will filter all letters and other symbols except digits for software keyboards. Only digital keyboard will appear on smartphones.

edit_text.keyListener = DigitsKeyListener.getInstance(context.getString(R.string.vin_code_mask))

I also usually set maxLength, filters, inputType.

SQL Server function to return minimum date (January 1, 1753)

This is what I use to get the minimum date in SQL Server. Please note that it is globalisation friendly:

CREATE FUNCTION [dbo].[DateTimeMinValue]()
RETURNS datetime
    CAST('17530101' AS datetime))

Call using:

SELECT [dbo].[DateTimeMinValue]()

How to visualize an XML schema?

We use Liquid XML Studio, it provides a intuitive editable representation of an XSD schema. It also shows the annotations inline, which we find very useful and the split code/gfx view is invaluable when writting or editing an XSD.

Liquid XML Studio XSD Editor

Start / Stop a Windows Service from a non-Administrator user account

There is a free GUI Tool ServiceSecurityEditor

Which allows you to edit Windows Service permissions. I have successfully used it to give a non-Administrator user the rights to start and stop a service.

I had used "sc sdset" before I knew about this tool.

ServiceSecurityEditor feels like cheating, it's that easy :)

.attr("disabled", "disabled") issue


  if (something) {
     console.log("A:"+$target.prev("input")) // gives out the right object
     $target.toggleClass("open").prev("input").attr("disabled", "disabled");
     console.log("A:"+$target.prev("input")) // any thing from there for a single click?
     $target.toggleClass("open").prev("input").removeAttr("disabled"); //this works

How to install a gem or update RubyGems if it fails with a permissions error

I used this and worked.

$ sudo chown myuser /var/lib/gems

Firing a Keyboard Event in Safari, using JavaScript

I am not very good with this but KeyboardEvent => see KeyboardEvent is initialized with initKeyEvent .
Here is an example for emitting event on <input type="text" /> element

document.getElementById("txbox").addEventListener("keypress", function(e) {_x000D_
  alert("Event " + e.type + " emitted!\nKey / Char Code: " + e.keyCode + " / " + e.charCode);_x000D_
}, false);_x000D_
document.getElementById("btn").addEventListener("click", function(e) {_x000D_
  var doc = document.getElementById("txbox");_x000D_
  var kEvent = document.createEvent("KeyboardEvent");_x000D_
  kEvent.initKeyEvent("keypress", true, true, null, false, false, false, false, 74, 74);_x000D_
}, false);
<input id="txbox" type="text" value="" />_x000D_
<input id="btn" type="button" value="CLICK TO EMIT KEYPRESS ON TEXTBOX" />

Creating email templates with Django

If you want dynamic email templates for your mail then save the email content in your database tables. This is what i saved as HTML code in database =

<p>Hello.. {{ first_name }} {{ last_name }}.  <br> This is an <strong>important</strong> {{ message }}
<br> <b> By Admin.</b>

 <p style='color:red'> Good Day </p>

In your views:

from django.core.mail import EmailMultiAlternatives
from django.template.loader import get_template

def dynamic_email(request):
    application_obj = AppDetails.objects.get(id=1)
    subject = 'First Interview Call'
    email =
    to_email =
    message = application_obj.message

    text_content = 'This is an important message.'
    d = {'first_name': application_obj.first_name,'message':message}
    htmly = FirstInterviewCall.objects.get(id=1).html_content #this is what i have saved previously in database which i have to send as Email template as mentioned above HTML code

    open("partner/templates/first_interview.html", "w").close() # this is the path of my file partner is the app, Here i am clearing the file content. If file not found it will create one on given path.
    text_file = open("partner/templates/first_interview.html", "w") # opening my file
    text_file.write(htmly) #putting HTML content in file which i saved in DB
    text_file.close() #file close

    htmly = get_template('first_interview.html')
    html_content = htmly.render(d)  
    msg = EmailMultiAlternatives(subject, text_content, email, [to_email])
    msg.attach_alternative(html_content, "text/html")

This will send the dynamic HTML template what you have save in Db.

How to hide close button in WPF window?

Try adding a Closing event to the window. Add this code to the event handler.

e.Cancel = true;

This will prevent the window from closing. This has the same effect as hiding the close button.

Python: find position of element in array

As Aaron states, you can use .index(value), but because that will throw an exception if value is not present, you should handle that case, even if you're sure it will never happen. A couple options are by checking its presence first, such as:

if value in my_list:
    value_index = my_list.index(value)

or by catching the exception as in:

    value_index = my_list.index(value)
    value_index = -1

You can never go wrong with proper error handling.

Conditional Logic on Pandas DataFrame

In [34]: import pandas as pd

In [35]: import numpy as np

In [36]:  df = pd.DataFrame([1,2,3,4], columns=["data"])

In [37]: df
0     1
1     2
2     3
3     4

In [38]: df["desired_output"] = np.where(df["data"] <2.5, "False", "True")

In [39]: df
   data desired_output
0     1          False
1     2          False
2     3           True
3     4           True

Angular ng-repeat Error "Duplicates in a repeater are not allowed."

My JSON response was like this:

      "index": 1,
      "name": "Samantha",
      "rarity": "Scarborough",
      "email": "[email protected]"
      "index": 2,
      "name": "Amanda",
      "rarity": "Vick",
      "email": "[email protected]"

So, I used ng-repeat = "item in variables.items" to display it.

What is an idempotent operation?

Quite a detailed and technical answers. Just adding a simple definition.

Idempotent = Re-runnable

For example, Create operation in itself is not guaranteed to run without error if executed more than once. But if there is an operation CreateOrUpdate then it states re-runnability (Idempotency).

How to affect other elements when one element is hovered

Big thanks to Mike and Robertc for their helpful posts!

If you have two elements in your HTML and you want to :hover over one and target a style change in the other the two elements must be directly related--parents, children or siblings. This means that the two elements either must be one inside the other or must both be contained within the same larger element.

I wanted to display definitions in a box on the right side of the browser as my users read through my site and :hover over highlighted terms; therefore, I did not want the 'definition' element to be displayed inside the 'text' element.

I almost gave up and just added javascript to my page, but this is the future dang it! We should not have to put up with back sass from CSS and HTML telling us where we have to place our elements to achieve the effects we want! In the end we compromised.

While the actual HTML elements in the file must be either nested or contained in a single element to be valid :hover targets to each other, the css position attribute can be used to display any element where ever you want. I used position:fixed to place the target of my :hover action where I wanted it on the user's screen regardless to its location in the HTML document.

The html:

<div id="explainBox" class="explainBox"> /*Common parent*/

  <a class="defP" id="light" href="http://en.wikipedia.or/wiki/Light">Light                            /*highlighted term in text*/
  </a> is as ubiquitous as it is mysterious. /*plain text*/

  <div id="definitions"> /*Container for :hover-displayed definitions*/
    <p class="def" id="light"> /*example definition entry*/ Light:
      <br/>Short Answer: The type of energy you see


The css:

/*read: "when user hovers over #light somewhere inside #explainBox
    set display to inline-block for #light directly inside of #definitions.*/

#explainBox #light:hover~#definitions>#light {
  display: inline-block;

.def {
  display: none;

#definitions {
  background-color: black;
  position: fixed;
  /*position attribute*/
  top: 5em;
  /*position attribute*/
  right: 2em;
  /*position attribute*/
  width: 20em;
  height: 30em;
  border: 1px solid orange;
  border-radius: 12px;
  padding: 10px;

In this example the target of a :hover command from an element within #explainBox must either be #explainBox or also within #explainBox. The position attributes assigned to #definitions force it to appear in the desired location (outside #explainBox) even though it is technically located in an unwanted position within the HTML document.

I understand it is considered bad form to use the same #id for more than one HTML element; however, in this case the instances of #light can be described independently due to their respective positions in uniquely #id'd elements. Is there any reason not to repeat the id #light in this case?

Storing data into list with class

If you want to instantiate and add in the same line, you'd have to do something like this:

lstemail.Add(new EmailData { FirstName = "JOhn", LastName = "Smith", Location = "Los Angeles" });

or just instantiate the object prior, and add it directly in:

EmailData data = new EmailData();
data.FirstName = "JOhn";
data.LastName = "Smith";
data.Location = "Los Angeles"


Is there a simple, elegant way to define singletons?

class Singleton(object[,...]):

    staticVar1 = None
    staticVar2 = None

    def __init__(self):
        if self.__class__.staticVar1==None :
            # create class instance variable for instantiation of class
            # assign class instance variable values to class static variables
            # assign class static variable values to class instance variables

Changing the highlight color when selecting text in an HTML text input

It seems like when you define the border inside of a focus pseudo element style declaration it uses that instead of the normal blue border. Using that you can define a style that is exactly the same as the element border.

input:focus, textarea:focus {_x000D_
    border:1px solid gray;_x000D_
#textarea  {_x000D_
  width:calc(100% - 20px);_x000D_
<textarea id="textarea">yo</textarea>

Here is a modified border style:

input:focus, textarea:focus {_x000D_
    border:2px dotted red;_x000D_
#textarea  {_x000D_
  width:calc(100% - 20px);_x000D_
<textarea id="textarea">yo</textarea>

Angular pass callback function to child component as @Input similar to AngularJS way

In some cases, you might need business logic to be performed by a parent component. In the example below we have a child component that renders table row depending on the logic provided by the parent component:

  template: '<table-component [getRowColor]="getColor"></table-component>',
  directives: [TableComponent]
export class ParentComponent {

 // Pay attention on the way this function is declared. Using fat arrow (=>) declaration 
 // we can 'fixate' the context of `getColor` function
 // so that it is bound to ParentComponent as if .bind(this) was used.
 getColor = (row: Row) => {
    return this.fancyColorService.getUserFavoriteColor(row);


export class TableComponent{
  // This will be bound to the ParentComponent.getColor. 
  // I found this way of declaration a bit safer and convenient than just raw Function declaration
  @Input('getRowColor') getRowColor: (row: Row) => Color;

    // Notice that `getRowColor` function holds parent's context because of a fat arrow function used in the parent
    const color = this.getRowColor(row);
    renderRow(row, color);

So, I wanted to demonstrate 2 things here:

  1. Fat arrow (=>) functions instead of .bind(this) to hold the right context;
  2. Typesafe declaration of a callback function in the child component.

Convert char to int in C and C++

Use static_cast<int>:

int num = static_cast<int>(letter); // if letter='a', num=97

Edit: You probably should try to avoid to use (int)

int num = (int) letter;

check out Why use static_cast<int>(x) instead of (int)x? for more info.

SVN Commit failed, access forbidden

You can get the "Forbidden" error if your user account lacks access permissions to a repository or repository path; it makes sense to check authorization settings for your user account. Make sure your system administrator hasn't provided you with No Access permission to the repository path.

If you are sure that permissions are set correctly, then double-check the URL you use. URLs in Apache Subversion are case-sensitive.

Additionally, I advise you to read articles on authorization in Subversion and VisualSVN Server:

"The file "" couldn't be opened because you don't have permission to view it" when running app in Xcode 6 Beta 4

I changed name to new name then I returned the old name to my project and it helped me.

Passing arguments to "make run"

Here's another solution that could help with some of these use cases:

    $(PYTHON) $@

In other words, pick some prefix (test- in this case), and then pass the target name directly to the program/runner. I guess this is mostly useful if there is some runner script involved that can unwrap the target name into something useful for the underlying program.

batch to copy files with xcopy

Based on xcopy help, I tried and found that following works perfectly for me (tried on Win 7)

xcopy C:\folder1 C:\folder2\folder1 /E /C /I /Q /G /H /R /K /Y /Z /J

Drop all the tables, stored procedures, triggers, constraints and all the dependencies in one sql statement

The best thing to do it is "Generate scripts for Drop"

Select Database -> Right Click -> Tasks -> Generate Scripts - will open wizard for generating scripts

after choosing objects in set Scripting option click Advanced Button

  • -> Set option 'Script to create' to true (want to create)

  • -> Set option 'Script to Drop' to true (want to drop)

  • -> Select the Check box to select objects wish to create script

  • -> Select the choice to write script (File, New window, Clipboard)

  • It includes dependent objects by default.(and will drop constraint at first)

    Execute the script

This way we can customize our script.

How do I upgrade PHP in Mac OS X?

Option #1

As recommended here, this site provides a convenient, up-to-date one liner.

This doesn't overwrite the base version of PHP on your system, but instead installs it cleanly in /usr/local/php5.

Option #2

My preferred method is to just install via Homebrew.

C++ -- expected primary-expression before ' '

You should not be repeating the string part when sending parameters.

int wordLength = wordLengthFunction(word); //you do not put string word here.

How to commit to remote git repository

Have you tried git push? has a nice section dealing with remote repositories.

You can also get help from the command line using the --help option. For example:

% git push --help
GIT-PUSH(1)                             Git Manual                             GIT-PUSH(1)

       git-push - Update remote refs along with associated objects

       git push [--all | --mirror | --tags] [-n | --dry-run] [--receive-pack=<git-receive-pack>]
                  [--repo=<repository>] [-f | --force] [-v | --verbose] [-u | --set-upstream]
                  [<repository> [<refspec>...]]

Allowed memory size of 536870912 bytes exhausted in Laravel

Share the lines of code executed when you make this request. There might be an error in your code.

Also, you can change the memory limit in your php.ini file via the memory_limit setting. Try doubling your memory to 64M. If this doesn't work you can try doubling it again, but I'd bet the problem is in your code.

ini_set('memory_limit', '64M');

How to embed YouTube videos in PHP?

Use a regex to extract the "video id" after watch?v=

Store the video id in a variable, let's call this variable vid

Get the embed code from a random video, remove the video id from the embed code and replace it with the vid you got.

I don't know how to deal with regex in php, but it shouldn't be too hard

Here's example code in python:

>>> ytlink = ''
>>> import re
>>> vid = re.findall( r'v\=([\-\w]+)', ytlink )[0]
>>> vid
>>> print '''<object width="425" height="344"><param name="movie" value=""></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object>''' % (vid,vid)
<object width="425" height="344"><param name="movie" value=""></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object>

The regular expression v\=([\-\w]+) captures a (sub)string of characters and dashes that comes after v=