Programs & Examples On #Connection leaks

What is a good practice to check if an environmental variable exists or not?

To be on the safe side use

os.getenv('FOO') or 'bar'

A corner case with the above answers is when the environment variable is set but is empty

For this special case you get

print(os.getenv('FOO', 'bar'))
# prints new line - though you expected `bar`


if "FOO" in os.environ:
    print("FOO is here")
# prints FOO is here - however its not

To avoid this just use or

os.getenv('FOO') or 'bar'

Then you get

print(os.getenv('FOO') or 'bar')
# bar

When do we have empty environment variables?

You forgot to set the value in the .env file

# .env

or exported as

$ export FOO=

or forgot to set it in

os.environ['FOO'] = ''

Update: if in doubt, check out these one-liners

>>> import os; os.environ['FOO'] = ''; print(os.getenv('FOO', 'bar'))

$ FOO= python -c "import os; print(os.getenv('FOO', 'bar'))"

SQL Server Error : String or binary data would be truncated

This error is usually encountered when inserting a record in a table where one of the columns is a VARCHAR or CHAR data type and the length of the value being inserted is longer than the length of the column.

I am not satisfied how Microsoft decided to inform with this "dry" response message, without any point of where to look for the answer.

Why doesn't importing java.util.* include Arrays and Lists?

The difference between

import java.util.*;


import java.util.*;
import java.util.List;
import java.util.Arrays;

becomes apparent when the code refers to some other List or Arrays (for example, in the same package, or also imported generally). In the first case, the compiler will assume that the Arrays declared in the same package is the one to use, in the latter, since it is declared specifically, the more specific java.util.Arrays will be used.

Copy data from one existing row to another existing row in SQL?

Try this:

UPDATE barang
SET ID FROM(SELECT tblkatalog.tblkatalog_id FROM tblkatalog 
WHERE tblkatalog.tblkatalog_nomor = barang.NO_CAT) WHERE barang.NO_CAT <>'';

Java: How to set Precision for double value?

To set precision for double values DecimalFormat is good technique. To use this class import java.text.DecimalFormat and create object of it for example

double no=12.786;
DecimalFormat dec = new DecimalFormat("#0.00");

So it will print two digits after decimal point here it will print 12.79

How do I display the current value of an Android Preference in the Preference summary?

After several hours I've been spent to solve such problem I've implemented this code:

[UPDATE: the final version listing]

public class MyPreferencesActivity extends PreferenceActivity {
    ListPreference m_updateList;
    protected void onCreate(Bundle savedInstanceState) {

        m_updateList = (ListPreference) findPreference(getString(R.string.pref_update_interval_key));
        String currentValue = m_updateList.getValue();
        if (currentValue == null) {
            currentValue = m_updateList.getValue();

        m_updateList.setOnPreferenceChangeListener(new OnPreferenceChangeListener() {
            public boolean onPreferenceChange(Preference preference, Object newValue) {
                return true;

    private void updateListSummary(String newValue) {
        int index = m_updateList.findIndexOfValue(newValue);
        CharSequence entry = m_updateList.getEntries()[index];

That was the only solution that worked for me fine. Before I've tried to subclass from ListPreferences and to implement android:summary="bla bla bla %s". Neither worked.

"code ." Not working in Command Line for Visual Studio Code on OSX/Mac

I've tried install add code command to PATH with Visual Studio Code's command pannel, but it's disabled after restart bash. if you want it be consolidated, just create a code file in your PATH; I create a code file in usr/local/bin and add

#!/usr/bin/env bash
function realpath() { python -c "import os,sys;print(os.path.realpath(sys.argv[1]))" "$0"; }
CONTENTS="/Applications/Visual Studio"
exit $?

just replace this CONTENTS with your VS Code's installed path. and don't forget make it excuteable with chmod +x /usr/local/bin/code

How do I print the content of a .txt file in Python?

Just do this:

>>> with open("path/to/file") as f: # The with keyword automatically closes the file when you are done
...     print

This will print the file in the terminal.

SVN "Already Locked Error"

TortoiseSVN users: right click on the root project directory > TortoiseSVN > Clean up... (make sure you check all the boxes). This worked for me.

bootstrap button shows blue outline when clicked

Override the exact bootstrap statements:

.btn-primary.focus, .btn-primary:focus, .btn-primary:not(:disabled):not(.disabled).active:focus,.btn-primary:not(:disabled):not(.disabled):active:focus,.show>.btn-primary.dropdown-toggle:focus{
 box-shadow: none;

concat scope variables into string in angular directive expression

You can just concat the values using +

<a ng-click="$navigate.go('#/path/' + obj.val1 + '/' + obj.val2)">{{obj.val1}}, {{obj.val2}}</a>

Simple example on jsfiddle

I am sure the code you posted is a simplified example, if your path building is more complex I would recommend extracting out a function (or service) that would build your urls so you can effectively write unit test.

UnicodeEncodeError: 'ascii' codec can't encode character at special name

Try setting the system default encoding as utf-8 at the start of the script, so that all strings are encoded using that.

Example -

import sys

The above should set the default encoding as utf-8 .

Ajax success function

It is because Ajax is asynchronous, the success or the error function will be called later, when the server answer the client. So, just move parts depending on the result into your success function like that :


            url: myAjax.ajaxurl,
            data: {action: 'submit_data', info: info},
            success: function(data) {
                successmessage = 'Data was succesfully captured';
            error: function(data) {
                successmessage = 'Error';

        return false;

How to escape indicator characters (i.e. : or - ) in YAML

According to the YAML spec, neither the : nor the - should be a problem. : is only a key separator with a space after it, and - is only an array indicator at the start of a line with a space after it.

But if your YAML implementation has a problem with it, you potentially have lots of options:

- url: ''
- url: ""
- url:
- url: >-
- url: |-

There is explicitly no form of escaping possible in "plain style", however.

Set height of chart in Chart.js

He's right. If you want to stay with jQuery you could do this

var ctx = $('#myChart')[0];
ctx.height = 500;


var ctx = $('#myChart');

Java 8 Lambda filter by Lists

Something like:>{>u.getName().equals(c.getName()).count()>0

This is however not an awfully efficient way to do it. Unless the collections are very small, you will be better of building a set of user names and using that in the condition.

Set content of HTML <span> with Javascript

With modern browsers, you can set the textContent property, see Node.textContent:

var span = document.getElementById("myspan");
span.textContent = "some text";

Javascript querySelector vs. getElementById

The functions getElementById and getElementsByClassName are very specific, while querySelector and querySelectorAll are more elaborate. My guess is that they will actually have a worse performance.

Also, you need to check for the support of each function in the browsers you are targetting. The newer it is, the higher probability of lack of support or the function being "buggy".

Yii2 data provider default sorting

Try to this one

$dataProvider = new ActiveDataProvider([
    'query' => $query,

$sort = $dataProvider->getSort();

$sort->defaultOrder = ['id' => SORT_ASC];


When & why to use delegates?

Delegates are extremely useful when wanting to declare a block of code that you want to pass around. For example when using a generic retry mechanism.


function Retry(Delegate func, int numberOfTimes)
    catch { if(numberOfTimes blabla) func.Invoke(); etc. etc. }

Or when you want to do late evaluation of code blocks, like a function where you have some Transform action, and want to have a BeforeTransform and an AfterTransform action that you can evaluate within your Transform function, without having to know whether the BeginTransform is filled, or what it has to transform.

And of course when creating event handlers. You don't want to evaluate the code now, but only when needed, so you register a delegate that can be invoked when the event occurs.

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

I just add the following in App_Start / WebApiConfig.cs class in my MVC Web API project.

    .Add(new MediaTypeHeaderValue("text/html") );

That makes sure you get JSON on most queries, but you can get XML when you send text/xml.

If you need to have the response Content-Type as application/json please check Todd's answer below.

NameSpace is using System.Net.Http.Headers.

Change working directory in my current shell context when running Node script

The correct way to change directories is actually with process.chdir(directory). Here's an example from the documentation:

console.log('Starting directory: ' + process.cwd());
try {
  console.log('New directory: ' + process.cwd());
catch (err) {
  console.log('chdir: ' + err);

This is also testable in the Node.js REPL:

[monitor@s2 ~]$ node
> process.cwd()
> process.chdir('../');
> process.cwd();

SVN repository backup strategies

There's a script available on the Subversion web site that's quite handy for automating backups.

How best to determine if an argument is not sent to the JavaScript function

This is one of the few cases where I find the test:

if(! argument2) {  


works quite nicely and carries the correct implication syntactically.

(With the simultaneous restriction that I wouldn't allow a legitimate null value for argument2 which has some other meaning; but that would be really confusing.)


This is a really good example of a stylistic difference between loosely-typed and strongly-typed languages; and a stylistic option that javascript affords in spades.

My personal preference (with no criticism meant for other preferences) is minimalism. The less the code has to say, as long as I'm consistent and concise, the less someone else has to comprehend to correctly infer my meaning.

One implication of that preference is that I don't want to - don't find it useful to - pile up a bunch of type-dependency tests. Instead, I try to make the code mean what it looks like it means; and test only for what I really will need to test for.

One of the aggravations I find in some other peoples' code is needing to figure out whether or not they expect, in the larger context, to actually run into the cases they are testing for. Or if they are trying to test for everything possible, on the chance that they don't anticipate the context completely enough. Which means I end up needing to track them down exhaustively in both directions before I can confidently refactor or modify anything. I figure that there's a good chance they might have put those various tests in place because they foresaw circumstances where they would be needed (and which usually aren't apparent to me).

(I consider that a serious downside in the way these folks use dynamic languages. Too often people don't want to give up all the static tests, and end up faking it.)

I've seen this most glaringly in comparing comprehensive ActionScript 3 code with elegant javascript code. The AS3 can be 3 or 4 times the bulk of the js, and the reliability I suspect is at least no better, just because of the number (3-4X) of coding decisions that were made.

As you say, Shog9, YMMV. :D

Referencing value in a closed Excel workbook using INDIRECT?

Check INDEX Function:


Generating random number between 1 and 10 in Bash Shell Script

To generate random numbers with bash use the $RANDOM internal Bash function. Note that $RANDOM should not be used to generate an encryption key. $RANDOM is generated by using your current process ID (PID) and the current time/date as defined by the number of seconds elapsed since 1970.

 echo $RANDOM % 10 + 1 | bc

What is a CSRF token? What is its importance and how does it work?

The Cloud Under blog has a good explanation of CSRF tokens. (archived)

Imagine you had a website like a simplified Twitter, hosted on Signed in users can enter some text (a tweet) into a form that’s being sent to the server as a POST request and published when they hit the submit button. On the server the user is identified by a cookie containing their unique session ID, so your server knows who posted the Tweet.

The form could be as simple as that:

 <form action="" method="POST">
   <input type="text" name="tweet">
   <input type="submit">

Now imagine, a bad guy copies and pastes this form to his malicious website, let’s say The form would still work. As long

as a user is signed in to your Twitter (i.e. they’ve got a valid session cookie for, the POST request would be sent to and processed as usual when the user clicks the submit button.

So far this is not a big issue as long as the user is made aware about what the form exactly does, but what if our bad guy tweaks the form like this:

 <form action="" method="POST">
   <input type="hidden" name="tweet" value="Buy great products at">
   <input type="submit" value="Click to win!">

Now, if one of your users ends up on the bad guy’s website and hits the “Click to win!” button, the form is submitted to

your website, the user is correctly identified by the session ID in the cookie and the hidden Tweet gets published.

If our bad guy was even worse, he would make the innocent user submit this form as soon they open his web page using JavaScript, maybe even completely hidden away in an invisible iframe. This basically is cross-site request forgery.

A form can easily be submitted from everywhere to everywhere. Generally that’s a common feature, but there are many more cases where it’s important to only allow a form being submitted from the domain where it belongs to.

Things are even worse if your web application doesn’t distinguish between POST and GET requests (e.g. in PHP by using $_REQUEST instead of $_POST). Don’t do that! Data altering requests could be submitted as easy as <img src="">, embedded in a malicious website or even an email.

How do I make sure a form can only be submitted from my own website? This is where the CSRF token comes in. A CSRF token is a random, hard-to-guess string. On a page with a form you want to protect, the server would generate a random string, the CSRF token, add it to the form as a hidden field and also remember it somehow, either by storing it in the session or by setting a cookie containing the value. Now the form would look like this:

    <form action="" method="POST">
      <input type="hidden" name="csrf-token" value="nc98P987bcpncYhoadjoiydc9ajDlcn">
      <input type="text" name="tweet">
      <input type="submit">

When the user submits the form, the server simply has to compare the value of the posted field csrf-token (the name doesn’t

matter) with the CSRF token remembered by the server. If both strings are equal, the server may continue to process the form. Otherwise the server should immediately stop processing the form and respond with an error.

Why does this work? There are several reasons why the bad guy from our example above is unable to obtain the CSRF token:

Copying the static source code from our page to a different website would be useless, because the value of the hidden field changes with each user. Without the bad guy’s website knowing the current user’s CSRF token your server would always reject the POST request.

Because the bad guy’s malicious page is loaded by your user’s browser from a different domain ( instead of, the bad guy has no chance to code a JavaScript, that loads the content and therefore our user’s current CSRF token from your website. That is because web browsers don’t allow cross-domain AJAX requests by default.

The bad guy is also unable to access the cookie set by your server, because the domains wouldn’t match.

When should I protect against cross-site request forgery? If you can ensure that you don’t mix up GET, POST and other request methods as described above, a good start would be to protect all POST requests by default.

You don’t have to protect PUT and DELETE requests, because as explained above, a standard HTML form cannot be submitted by a browser using those methods.

JavaScript on the other hand can indeed make other types of requests, e.g. using jQuery’s $.ajax() function, but remember, for AJAX requests to work the domains must match (as long as you don’t explicitly configure your web server otherwise).

This means, often you do not even have to add a CSRF token to AJAX requests, even if they are POST requests, but you will have to make sure that you only bypass the CSRF check in your web application if the POST request is actually an AJAX request. You can do that by looking for the presence of a header like X-Requested-With, which AJAX requests usually include. You could also set another custom header and check for its presence on the server side. That’s safe, because a browser would not add custom headers to a regular HTML form submission (see above), so no chance for Mr Bad Guy to simulate this behaviour with a form.

If you’re in doubt about AJAX requests, because for some reason you cannot check for a header like X-Requested-With, simply pass the generated CSRF token to your JavaScript and add the token to the AJAX request. There are several ways of doing this; either add it to the payload just like a regular HTML form would, or add a custom header to the AJAX request. As long as your server knows where to look for it in an incoming request and is able to compare it to the original value it remembers from the session or cookie, you’re sorted.

Java way to check if a string is palindrome

I'm new to java and I'm taking up your question as a challenge to improve my knowledge as well so please forgive me if this does not answer your question well:

import java.util.ArrayList;
import java.util.List;

public class PalindromeRecursiveBoolean {

    public static boolean isPalindrome(String str) {

        str = str.toUpperCase();
        char[] strChars = str.toCharArray();

        List<Character> word = new ArrayList<>();
        for (char c : strChars) {

        while (true) {
            if ((word.size() == 1) || (word.size() == 0)) {
                return true;
            if (word.get(0) == word.get(word.size() - 1)) {
                word.remove(word.size() - 1);
            } else {
                return false;


  1. If the string is made of no letters or just one letter, it is a palindrome.
  2. Otherwise, compare the first and last letters of the string.
    • If the first and last letters differ, then the string is not a palindrome
    • Otherwise, the first and last letters are the same. Strip them from the string, and determine whether the string that remains is a palindrome. Take the answer for this smaller string and use it as the answer for the original string then repeat from 1.

The only string manipulation is changing the string to uppercase so that you can enter something like 'XScsX'

git is not installed or not in the PATH

I did install git and tried again and got the same error. But running 'npm install' in a new command prompt window worked for me. Restarting the machine is not required.

What is a good pattern for using a Global Mutex in C#?

A global Mutex is not only to ensure to have only one instance of an application. I personally prefer using Microsoft.VisualBasic to ensure single instance application like described in What is the correct way to create a single-instance WPF application? (Dale Ragan answer)... I found that's easier to pass arguments received on new application startup to the initial single instance application.

But regarding some previous code in this thread, I would prefer to not create a Mutex each time I want to have a lock on it. It could be fine for a single instance application but in other usage it appears to me has overkill.

That's why I suggest this implementation instead:


static MutexGlobal _globalMutex = null;
static MutexGlobal GlobalMutexAccessEMTP
        if (_globalMutex == null)
            _globalMutex = new MutexGlobal();
        return _globalMutex;

using (GlobalMutexAccessEMTP.GetAwaiter())

Mutex Global Wrapper:

using System;
using System.Reflection;
using System.Runtime.InteropServices;
using System.Security.AccessControl;
using System.Security.Principal;
using System.Threading;

namespace HQ.Util.General.Threading
    public class MutexGlobal : IDisposable
        // ************************************************************************
        public string Name { get; private set; }
        internal Mutex Mutex { get; private set; }
        public int DefaultTimeOut { get; set; }
        public Func<int, bool> FuncTimeOutRetry { get; set; }

        // ************************************************************************
        public static MutexGlobal GetApplicationMutex(int defaultTimeOut = Timeout.Infinite)
            return new MutexGlobal(defaultTimeOut, ((GuidAttribute)Assembly.GetExecutingAssembly().GetCustomAttributes(typeof(GuidAttribute), false).GetValue(0)).Value);

        // ************************************************************************
        public MutexGlobal(int defaultTimeOut = Timeout.Infinite, string specificName = null)
                if (string.IsNullOrEmpty(specificName))
                    Name = Guid.NewGuid().ToString();
                    Name = specificName;

                Name = string.Format("Global\\{{{0}}}", Name);

                DefaultTimeOut = defaultTimeOut;

                FuncTimeOutRetry = DefaultFuncTimeOutRetry;

                var allowEveryoneRule = new MutexAccessRule(new SecurityIdentifier(WellKnownSidType.WorldSid, null), MutexRights.FullControl, AccessControlType.Allow);
                var securitySettings = new MutexSecurity();

                Mutex = new Mutex(false, Name, out bool createdNew, securitySettings);

                if (Mutex == null)
                    throw new Exception($"Unable to create mutex: {Name}");
            catch (Exception ex)
                Log.Log.Instance.AddEntry(Log.LogType.LogException, $"Unable to create Mutex: {Name}", ex);

        // ************************************************************************
        /// <summary>
        /// </summary>
        /// <param name="timeOut"></param>
        /// <returns></returns>
        public MutexGlobalAwaiter GetAwaiter(int timeOut)
            return new MutexGlobalAwaiter(this, timeOut);

        // ************************************************************************
        /// <summary>
        /// </summary>
        /// <param name="timeOut"></param>
        /// <returns></returns>
        public MutexGlobalAwaiter GetAwaiter()
            return new MutexGlobalAwaiter(this, DefaultTimeOut);

        // ************************************************************************
        /// <summary>
        /// This method could either throw any user specific exception or return 
        /// true to retry. Otherwise, retruning false will let the thread continue
        /// and you should verify the state of MutexGlobalAwaiter.HasTimedOut to 
        /// take proper action depending on timeout or not. 
        /// </summary>
        /// <param name="timeOutUsed"></param>
        /// <returns></returns>
        private bool DefaultFuncTimeOutRetry(int timeOutUsed)
            // throw new TimeoutException($"Mutex {Name} timed out {timeOutUsed}.");

            Log.Log.Instance.AddEntry(Log.LogType.LogWarning, $"Mutex {Name} timeout: {timeOutUsed}.");
            return true; // retry

        // ************************************************************************
        public void Dispose()
            if (Mutex != null)

        // ************************************************************************



using System;

namespace HQ.Util.General.Threading
    public class MutexGlobalAwaiter : IDisposable
        MutexGlobal _mutexGlobal = null;

        public bool HasTimedOut { get; set; } = false;

        internal MutexGlobalAwaiter(MutexGlobal mutexEx, int timeOut)
            _mutexGlobal = mutexEx;

                HasTimedOut = !_mutexGlobal.Mutex.WaitOne(timeOut, false);
                if (! HasTimedOut) // Signal received
            } while (_mutexGlobal.FuncTimeOutRetry(timeOut));

        #region IDisposable Support
        private bool disposedValue = false; // To detect redundant calls

        protected virtual void Dispose(bool disposing)
            if (!disposedValue)
                if (disposing)

                // TODO: free unmanaged resources (unmanaged objects) and override a finalizer below.
                // TODO: set large fields to null.

                disposedValue = true;
        // TODO: override a finalizer only if Dispose(bool disposing) above has code to free unmanaged resources.
        // ~MutexExAwaiter()
        // {
        //   // Do not change this code. Put cleanup code in Dispose(bool disposing) above.
        //   Dispose(false);
        // }

        // This code added to correctly implement the disposable pattern.
        public void Dispose()
            // Do not change this code. Put cleanup code in Dispose(bool disposing) above.
            // TODO: uncomment the following line if the finalizer is overridden above.
            // GC.SuppressFinalize(this);

Check that a input to UITextField is numeric only

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
    if(string.length > 0)
        NSCharacterSet *numbersOnly = [NSCharacterSet characterSetWithCharactersInString:@"0123456789"];
        NSCharacterSet *characterSetFromTextField = [NSCharacterSet characterSetWithCharactersInString:string];

        BOOL stringIsValid = [numbersOnly isSupersetOfSet:characterSetFromTextField];
        return stringIsValid;
    return YES;

Function to calculate distance between two coordinates

I have written a similar equation before - tested it and also got 1.6 km.

Your google maps was showing the DRIVING distance.

Your function is calculating as the crow flies (straight line distance).


    //This function takes in latitude and longitude of two location and returns the distance between them as the crow flies (in km)
    function calcCrow(lat1, lon1, lat2, lon2) 
      var R = 6371; // km
      var dLat = toRad(lat2-lat1);
      var dLon = toRad(lon2-lon1);
      var lat1 = toRad(lat1);
      var lat2 = toRad(lat2);

      var a = Math.sin(dLat/2) * Math.sin(dLat/2) +
        Math.sin(dLon/2) * Math.sin(dLon/2) * Math.cos(lat1) * Math.cos(lat2); 
      var c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1-a)); 
      var d = R * c;
      return d;

    // Converts numeric degrees to radians
    function toRad(Value) 
        return Value * Math.PI / 180;

Fail during installation of Pillow (Python module) in Linux

I had the ValueError: zlib is required unless explicitly disabled using --disable-zlib but upgrading pip from 7.x to 8.y resolved the problem.

So I would try to update tools before anything else.

That can be done using:

pip install --upgrade pip

How to set a:link height/width with css?

add display: block;

a-tag is an inline element so your height and width are ignored.

#header div#snav div a{

iPhone is not available. Please reconnect the device

I am using an iPhone SE iOS 13.6.1 and Xcode 13.5 and I faced the same issue. While the iPhone is not available. Please reconnect the device warning window is open, I turned off the iPhone, reopened and rebuilt the Xcode project, Trusted in the iPhone and my problem was solved.

Unable to find the requested .Net Framework Data Provider. It may not be installed. - when following mvc3 tutorial

Add these lines to your web.config file:

               <add name="MySQL Data Provider" invariant="MySql.Data.MySqlClient" description=".Net Framework Data Provider for MySQL" type="MySql.Data.MySqlClient.MySqlClientFactory,MySql.Data,  Version=, Culture=neutral, PublicKeyToken=C5687FC88969C44D"/>

Change your provider from MySQL to SQL Server or whatever database provider you are connecting to.

C++ inheritance - inaccessible base?

You have to do this:

class Bar : public Foo
    // ...

The default inheritance type of a class in C++ is private, so any public and protected members from the base class are limited to private. struct inheritance on the other hand is public by default.

How to clear the text of all textBoxes in the form?

You can try this code

protected override bool ProcessCmdKey(ref Message msg, Keys keyData)

            return true;

        return base.ProcessCmdKey(ref msg, keyData);

'mvn' is not recognized as an internal or external command,

Make sure you have your maven bin directory in the path and the JAVA_HOME property set

Returning pointer from a function

To my knowledge the use of the keyword new, does relatively the same thing as malloc(sizeof identifier). The code below demonstrates how to use the keyword new.

    void main(void){
        int* test;
        test = tester();
    int* tester(void){
        int *retMe;
        retMe = new int;//<----Here retMe is getting malloc for integer type
        *retMe = 12;<---- Initializes retMe... Note * dereferences retMe 
    return retMe;

build maven project with propriatery libraries included

A good way to achieve this is to have a Maven mirror server such as Sonatype Nexus. It is free and very easy to setup (Java web app). With Nexus one can have private (team, corporate etc) repository with a capability of deploying third party and internal apps into it, while also registering other Maven repositories as part of the same server. This way the local Maven settings would reference only the one private Nexus server and all the dependencies will be resolved using it.

Pandas df.to_csv("file.csv" encode="utf-8") still gives trash characters for minus sign

Your "bad" output is UTF-8 displayed as CP1252.

On Windows, many editors assume the default ANSI encoding (CP1252 on US Windows) instead of UTF-8 if there is no byte order mark (BOM) character at the start of the file. While a BOM is meaningless to the UTF-8 encoding, its UTF-8-encoded presence serves as a signature for some programs. For example, Microsoft Office's Excel requires it even on non-Windows OSes. Try:


That encoder will add the BOM.

connect to host localhost port 22: Connection refused

Make sure that /etc/hosts.allow contains:




OR - some other variant


INSURE that the first line in the file DOES NOT begin with ALL:ALL:DENY

NOTHING will be able to communicate with the host... on any port.

How can I declare a two dimensional string array?

When you are trying to create a multi-dimensional array all you need to do is add a comma to the declaration like so:

string[,] tablero = new string[3,3].

Correct use for angular-translate in controllers

EDIT: Please see the answer from PascalPrecht (the author of angular-translate) for a better solution.

The asynchronous nature of the loading causes the problem. You see, with {{ pageTitle | translate }}, Angular will watch the expression; when the localization data is loaded, the value of the expression changes and the screen is updated.

So, you can do that yourself:

.controller('FirstPageCtrl', ['$scope', '$filter', function ($scope, $filter) {
        function() { return $filter('translate')('HELLO_WORLD'); },
        function(newval) { $scope.pageTitle = newval; }

However, this will run the watched expression on every digest cycle. This is suboptimal and may or may not cause a visible performance degradation. Anyway it is what Angular does, so it cant be that bad...

Bootstrap 3 with remote Modal

If you don't want to send the full modal structure you can replicate the old behaviour doing something like this:

// this is just an example, remember to adapt the selectors to your code!
$('.modal-link').click(function(e) {
    var modal = $('#modal'), modalBody = $('#modal .modal-body');

        .on('', function () {

How can I show current location on a Google Map on Android Marshmallow?

For using FusedLocationProviderClient with Google Play Services 11 and higher:

see here: How to get current Location in GoogleMap using FusedLocationProviderClient

For using (now deprecated) FusedLocationProviderApi:

If your project uses Google Play Services 10 or lower, using the FusedLocationProviderApi is the optimal choice.

The FusedLocationProviderApi offers less battery drain than the old open source LocationManager API. Also, if you're already using Google Play Services for Google Maps, there's no reason not to use it.

Here is a full Activity class that places a Marker at the current location, and also moves the camera to the current position.

It also checks for the Location permission at runtime for Android 6 and later (Marshmallow, Nougat, Oreo). In order to properly handle the Location permission runtime check that is necessary on Android M/Android 6 and later, you need to ensure that the user has granted your app the Location permission before calling mGoogleMap.setMyLocationEnabled(true) and also before requesting location updates.

public class MapLocationActivity extends AppCompatActivity
        implements OnMapReadyCallback,
        LocationListener {

    GoogleMap mGoogleMap;
    SupportMapFragment mapFrag;
    LocationRequest mLocationRequest;
    GoogleApiClient mGoogleApiClient;
    Location mLastLocation;
    Marker mCurrLocationMarker;

    protected void onCreate(Bundle savedInstanceState)

        getSupportActionBar().setTitle("Map Location Activity");

        mapFrag = (SupportMapFragment) getSupportFragmentManager().findFragmentById(;

    public void onPause() {

        //stop location updates when Activity is no longer active
        if (mGoogleApiClient != null) {
            LocationServices.FusedLocationApi.removeLocationUpdates(mGoogleApiClient, this);

    public void onMapReady(GoogleMap googleMap)

        //Initialize Google Play Services
        if (android.os.Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
            if (ContextCompat.checkSelfPermission(this,
                    == PackageManager.PERMISSION_GRANTED) {
                //Location Permission already granted
            } else {
                //Request Location Permission
        else {

    protected synchronized void buildGoogleApiClient() {
        mGoogleApiClient = new GoogleApiClient.Builder(this)

    public void onConnected(Bundle bundle) {
        mLocationRequest = new LocationRequest();
        if (ContextCompat.checkSelfPermission(this,
                == PackageManager.PERMISSION_GRANTED) {
            LocationServices.FusedLocationApi.requestLocationUpdates(mGoogleApiClient, mLocationRequest, this);

    public void onConnectionSuspended(int i) {}

    public void onConnectionFailed(ConnectionResult connectionResult) {}

    public void onLocationChanged(Location location)
        mLastLocation = location;
        if (mCurrLocationMarker != null) {

        //Place current location marker
        LatLng latLng = new LatLng(location.getLatitude(), location.getLongitude());
        MarkerOptions markerOptions = new MarkerOptions();
        markerOptions.title("Current Position");
        mCurrLocationMarker = mGoogleMap.addMarker(markerOptions);

        //move map camera


    public static final int MY_PERMISSIONS_REQUEST_LOCATION = 99;
    private void checkLocationPermission() {
        if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION)
                != PackageManager.PERMISSION_GRANTED) {

            // Should we show an explanation?
            if (ActivityCompat.shouldShowRequestPermissionRationale(this,
                    Manifest.permission.ACCESS_FINE_LOCATION)) {

                // Show an explanation to the user *asynchronously* -- don't block
                // this thread waiting for the user's response! After the user
                // sees the explanation, try again to request the permission.
                new AlertDialog.Builder(this)
                        .setTitle("Location Permission Needed")
                        .setMessage("This app needs the Location permission, please accept to use location functionality")
                        .setPositiveButton("OK", new DialogInterface.OnClickListener() {
                            public void onClick(DialogInterface dialogInterface, int i) {
                                //Prompt the user once explanation has been shown
                                        new String[]{Manifest.permission.ACCESS_FINE_LOCATION},
                                        MY_PERMISSIONS_REQUEST_LOCATION );

            } else {
                // No explanation needed, we can request the permission.
                        new String[]{Manifest.permission.ACCESS_FINE_LOCATION},
                        MY_PERMISSIONS_REQUEST_LOCATION );

    public void onRequestPermissionsResult(int requestCode,
                                           String permissions[], int[] grantResults) {
        switch (requestCode) {
                // If request is cancelled, the result arrays are empty.
                if (grantResults.length > 0
                        && grantResults[0] == PackageManager.PERMISSION_GRANTED) {

                    // permission was granted, yay! Do the
                    // location-related task you need to do.
                    if (ContextCompat.checkSelfPermission(this,
                            == PackageManager.PERMISSION_GRANTED) {

                        if (mGoogleApiClient == null) {

                } else {

                    // permission denied, boo! Disable the
                    // functionality that depends on this permission.
                    Toast.makeText(this, "permission denied", Toast.LENGTH_LONG).show();

            // other 'case' lines to check for other
            // permissions this app might request



<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android=""
    android:orientation="vertical" android:layout_width="match_parent"

    <fragment xmlns:android=""



Show permission explanation if needed using an AlertDialog (this happens if the user denies a permission request, or grants the permission and then later revokes it in the settings):

enter image description here

Prompt the user for Location permission by calling ActivityCompat.requestPermissions():

enter image description here

Move camera to current location and place Marker when the Location permission is granted:

enter image description here

How can you run a Java program without main method?

Applets from what I remember do not need a main method, though I am not sure they are technically a program.

Cannot get Kerberos service ticket: KrbException: Server not found in Kerberos database (7)

In my case, My principal was kafka/[email protected] I got below lines in the terminal:

>>> KrbKdcReq send: #bytes read=190
>>> KdcAccessibility: remove
>>> KDCRep: init() encoding tag is 126 req type is 13
         cTime is Thu Oct 05 03:42:15 UTC 1995 812864535000
         sTime is Fri May 31 06:43:38 UTC 2019 1559285018000
         suSec is 111309
         error code is 7
         error Message is Server not found in Kerberos database
         cname is kafka/[email protected]
         sname is kafka/[email protected]
         msgType is 30

After hours of checking, I just found the below line has a wrong value in kafka_2.12-2.2.0/


Also I got two entries of and for same IP address.

I changed it to as listeners=SASL_PLAINTEXT:// Then it worked!

According to the below link, the principal should contain the Fully Qualified Domain Name (FQDN) of each host and it should be matched with the principal.

SQL Error: ORA-00922: missing or invalid option

You should not use space character while naming database objects. Even though it's possible by using double quotes(quoted identifiers), CREATE TABLE "chartered flight" ..., it's not recommended. Take a closer look here

How to determine whether a given Linux is 32 bit or 64 bit?

The command

$ arch    

is equivalent to

$ uname -m

but is twice as fast to type

How do I remove a MySQL database?

For Visual Studio, in the package manager console:


How to deploy a war file in Tomcat 7

You just need to put your war file in webapps and then start your server.

it will get deployed.

otherwise you can also use tomcat manager a webfront to upload & deploy your war remotely.

How to "z-index" to make a menu always on top of the content

you could put the style in container div menu with:

<div style="position:relative; z-index:10">
   <!--html menu-->

before enter image description here


enter image description here

PRINT statement in T-SQL

Query Analyzer buffers messages. The PRINT and RAISERROR statements both use this buffer, but the RAISERROR statement has a WITH NOWAIT option. To print a message immediately use the following:

RAISERROR ('Your message', 0, 1) WITH NOWAIT

RAISERROR will only display 400 characters of your message and uses a syntax similar to the C printf function for formatting text.

Please note that the use of RAISERROR with the WITH NOWAIT option will flush the message buffer, so all previously buffered information will be output also.

Could not create the Java virtual machine

Set the JVM memory:

export _JAVA_OPTIONS=-Xmx512M

Use PHP to convert PNG to JPG with compression?

This is a small example that will convert 'image.png' to 'image.jpg' at 70% image quality:

$image = imagecreatefrompng('image.png');
imagejpeg($image, 'image.jpg', 70);

Hope that helps

How to make a DIV always float on the screen in top right corner?

Use position:fixed, as previously stated, IE6 doesn't recognize position:fixed, but with some css magic you can get IE6 to behave:

html, body {
    height: 100%;
body #fixedElement {
    position:fixed !important;
    position: absolute; /*ie6 */
    bottom: 0;

The !important flag makes it so you don't have to use a conditional comment for IE. This will have #fixedElement use position:fixed in all browsers but IE, and in IE, position:absolute will take effect with bottom:0. This will simulate position:fixed for IE6

How to preventDefault on anchor tags?

The easiest solution I have found is this one :

<a href="#" ng-click="do(); $event.preventDefault()">Click</a>

Python function to convert seconds into minutes, hours, and days

Patching as well Ralph Bolton's answer. Moving to a class and moving tulp of tulp (intervals) to dictionary. Adding an optional rounded function depending of granularity (enable by default). Ready to translation using gettext (default is disable). This is intend to be load from an module. This is for python3 (tested 3.6 - 3.8)

import gettext
import locale
from itertools import chain

mylocale = locale.getdefaultlocale()
# see --> thx 
#localedir = os.path.join(os.path.dirname(__file__), 'locales')
# or python > 3.4:
    localedir = pathlib.Path(__file__).parent/'locales'
    lang_translations = gettext.translation('utils', localedir, 
    _ = lang_translations.gettext
except Exception as exc:
    print('Error: unexcept error while initializing translation:', file=sys.stderr)
    print(f'Error: {exc}', file=sys.stderr)
    print(f'Error: localedir={localedir}, languages={mylocale[0]}', file=sys.stderr)
    print('Error: translation has been disabled.', file=sys.stderr)
    _ = gettext.gettext

Here is the class:

class FormatTimestamp:
    """Convert seconds to, optional rounded, time depending of granularity's degrees.
        inspired by"""
    def __init__(self):
        # For now i haven't found a way to do it better
        # TODO: optimize ?!? ;)
        self.intervals = {
            # 'years'     :   31556952,  #
            # -> 2629746 seconds
            # But it's outputing some strange result :
            # So 3 seconds less (2629743) : 4 weeks, 2 days, 10 hours, 29 minutes and 3 seconds
            # than after 3 more seconds : 1 month ?!?
            # Google give me 2628000 seconds
            # So 3 seconds less (2627997): 4 weeks, 2 days, 9 hours, 59 minutes and 57 seconds
            # Strange as well 
            # So for the moment latest is week ...
            #'months'    :   2419200, # 60 * 60 * 24 * 7 * 4 
            'weeks'     :   604800,  # 60 * 60 * 24 * 7
            'days'      :   86400,    # 60 * 60 * 24
            'hours'     :   3600,    # 60 * 60
            'minutes'   :   60,
            'seconds'  :   1
        self.nextkey = {
            'seconds'   :   'minutes',
            'minutes'   :   'hours',
            'hours'     :   'days',
            'days'      :   'weeks',
            'weeks'     :   'weeks',
            #'months'    :   'months',
            #'years'     :   'years' # stop here
        self.translate = {
            'weeks'     :   _('weeks'),
            'days'      :   _('days'),
            'hours'     :   _('hours'),
            'minutes'   :   _('minutes'),
            'seconds'   :   _('seconds'),
            ## Single
            'week'      :   _('week'),
            'day'       :   _('day'),
            'hour'      :   _('hour'),
            'minute'    :   _('minute'),
            'second'    :   _('second'),
            ' and'      :   _('and'),
            ','         :   _(','),     # This is for compatibility
            ''          :   '\0'        # same here BUT we CANNOT pass empty string to gettext 
                                        # or we get : warning: Empty msgid.  It is reserved by GNU gettext:
                                        # gettext("") returns the header entry with
                                        # meta information, not the empty string.
                                        # Thx to --> - saved my day

    def convert(self, seconds, granularity=2, rounded=True, translate=False):
        """Proceed the conversion"""

        def _format(result):
            """Return the formatted result
            TODO : numpy / google docstrings"""
            start = 1 
            length = len(result)
            none = 0
            next_item = False
            for item in reversed(result[:]):
                if item['value']:
                    # if we have more than one item
                    if length - none > 1:
                        # This is the first 'real' item 
                        if start == 1:
                            item['punctuation'] = ''
                            next_item = True
                        elif next_item:
                            # This is the second 'real' item
                            # Happened 'and' to key name
                            item['punctuation'] = ' and'
                            next_item = False
                        # If there is more than two 'real' item
                        # than happened ','
                        elif 2 < start:
                            item['punctuation'] = ','
                            item['punctuation'] = ''
                        item['punctuation'] = ''
                    start += 1
                    none += 1
            return [ { 'value'        :   mydict['value'], 
                       'name'         :   mydict['name_strip'],
                       'punctuation'  :   mydict['punctuation'] } for mydict in result \
                                                                  if mydict['value'] is not None ]

        def _rstrip(value, name):
            """Rstrip 's' name depending of value"""
            if value == 1:
                name = name.rstrip('s')
            return name

        # Make sure granularity is an integer
        if not isinstance(granularity, int):
            raise ValueError(f'Granularity should be an integer: {granularity}')

        # For seconds only don't need to compute
        if seconds < 0:
            return 'any time now.'
        elif seconds < 60:
            return 'less than a minute.'

        result = []
        for name, count in self.intervals.items():
            value = seconds // count
            if value:
                seconds -= value * count
                name_strip = _rstrip(value, name)
                # save as dict: value, name_strip (eventually strip), name (for reference), value in seconds
                # and count (for reference)
                        'value'        :   value,
                        'name_strip'   :   name_strip,
                        'name'         :   name, 
                        'seconds'      :   value * count,
                        'count'        :   count
                if len(result) > 0:
                    # We strip the name as second == 0
                    name_strip = name.rstrip('s')
                    # adding None to key 'value' but keep other value
                    # in case when need to add seconds when we will 
                    # recompute every thing
                        'value'        :   None,
                        'name_strip'   :   name_strip,
                        'name'         :   name, 
                        'seconds'      :   0,
                        'count'        :   count

        # Get the length of the list
        length = len(result)
        # Don't need to compute everything / every time
        if length < granularity or not rounded:
            if translate:
                return ' '.join('{0} {1}{2}'.format(item['value'], _(self.translate[item['name']]), 
                                                _(self.translate[item['punctuation']])) \
                                                for item in _format(result))
                return ' '.join('{0} {1}{2}'.format(item['value'], item['name'], item['punctuation']) \
                                                for item in _format(result))

        start = length - 1
        # Reverse list so the firsts elements 
        # could be not selected depending on granularity.
        # And we can delete item after we had his seconds to next
        # item in the current list (result)
        for item in reversed(result[:]):
            if granularity <= start <= length - 1:
                # So we have to round
                current_index = result.index(item)
                next_index = current_index - 1
                # skip item value == None
                # if the seconds of current item is superior
                # to the half seconds of the next item: round
                if item['value'] and item['seconds'] > result[next_index]['count'] // 2:
                    # +1 to the next item (in seconds: depending on item count)
                    result[next_index]['seconds'] += result[next_index]['count']
                # Remove item which is not selected
                del result[current_index]
            start -= 1
        # Ok now recalculate everything
        # Reverse as well 
        for item in reversed(result[:]):
            # Check if seconds is superior or equal to the next item 
            # but not from 'result' list but from 'self.intervals' dict
            # Make sure it's not None
            if item['value']:
                next_item_name = self.nextkey[item['name']]
                # This mean we are at weeks
                if item['name'] == next_item_name:
                    # Just recalcul
                    item['value'] = item['seconds'] // item['count']
                    item['name_strip'] = _rstrip(item['value'], item['name'])
                # Stop to weeks to stay 'right' 
                elif item['seconds'] >= self.intervals[next_item_name]:
                    # First make sure we have the 'next item'
                    # found via -->
                    # maybe there is a faster way to do it ? - TODO
                    if any(search_item['name'] == next_item_name for search_item in result):
                        next_item_index = result.index(item) - 1
                        # Append to
                        result[next_item_index]['seconds'] += item['seconds']
                        # recalculate value
                        result[next_item_index]['value'] = result[next_item_index]['seconds'] // \
                        # strip or not
                        result[next_item_index]['name_strip'] = _rstrip(result[next_item_index]['value'],
                        # Creating 
                        next_item_index = result.index(item) - 1
                        # get count
                        next_item_count = self.intervals[next_item_name]
                        # convert seconds
                        next_item_value = item['seconds'] // next_item_count
                        # strip 's' or not
                        next_item_name_strip = _rstrip(next_item_value, next_item_name)
                        # added to dict
                        next_item = {
                                       'value'      :   next_item_value,
                                       'name_strip' :   next_item_name_strip,
                                       'name'       :   next_item_name,
                                       'seconds'    :   item['seconds'],
                                       'count'      :   next_item_count
                        # insert to the list
                        result.insert(next_item_index, next_item)
                    # Remove current item
                    del result[result.index(item)]
                    # for current item recalculate
                    # keys 'value' and 'name_strip'
                    item['value'] = item['seconds'] // item['count']
                    item['name_strip'] = _rstrip(item['value'], item['name'])
        if translate:
            return ' '.join('{0} {1}{2}'.format(item['value'], 
                                                _(self.translate[item['punctuation']])) \
                                                for item in _format(result))
            return ' '.join('{0} {1}{2}'.format(item['value'], item['name'], item['punctuation']) \
                                                for item in _format(result))

To use it:

myformater = FormatTimestamp()
myconverter = myformater.convert(seconds) 

granularity = 1 - 5, rounded = True / False, translate = True / False

Some test to show difference:

myformater = FormatTimestamp()
for firstrange in [131440, 563440, 604780, 2419180, 113478160]:
    print(f'#### Seconds : {firstrange} ####')
    print('\tFull - function: {0}'.format(display_time(firstrange, granularity=5)))
    print('\tFull -    class: {0}'.format(myformater.convert(firstrange, granularity=5))) 
    for secondrange in range(1, 6, 1):
        print('\tGranularity   this   answer ({0}): {1}'.format(secondrange, 
                                                                                granularity=secondrange, translate=False)))
        print('\tGranularity Bolton\'s answer ({0}): {1}'.format(secondrange, display_time(firstrange,
Seconds : 131440
    Full - function: 1 day, 12 hours, 30 minutes, 40 seconds
    Full -    class: 1 day, 12 hours, 30 minutes and 40 seconds
    Granularity   this   answer (1): 2 days
    Granularity Bolton's answer (1): 1 day
    Granularity   this   answer (2): 1 day and 13 hours
    Granularity Bolton's answer (2): 1 day, 12 hours
    Granularity   this   answer (3): 1 day, 12 hours and 31 minutes
    Granularity Bolton's answer (3): 1 day, 12 hours, 30 minutes
    Granularity   this   answer (4): 1 day, 12 hours, 30 minutes and 40 seconds
    Granularity Bolton's answer (4): 1 day, 12 hours, 30 minutes, 40 seconds
    Granularity   this   answer (5): 1 day, 12 hours, 30 minutes and 40 seconds
    Granularity Bolton's answer (5): 1 day, 12 hours, 30 minutes, 40 seconds
Seconds : 563440
    Full - function: 6 days, 12 hours, 30 minutes, 40 seconds
    Full -    class: 6 days, 12 hours, 30 minutes and 40 seconds
    Granularity   this   answer (1): 1 week
    Granularity Bolton's answer (1): 6 days
    Granularity   this   answer (2): 6 days and 13 hours
    Granularity Bolton's answer (2): 6 days, 12 hours
    Granularity   this   answer (3): 6 days, 12 hours and 31 minutes
    Granularity Bolton's answer (3): 6 days, 12 hours, 30 minutes
    Granularity   this   answer (4): 6 days, 12 hours, 30 minutes and 40 seconds
    Granularity Bolton's answer (4): 6 days, 12 hours, 30 minutes, 40 seconds
    Granularity   this   answer (5): 6 days, 12 hours, 30 minutes and 40 seconds
    Granularity Bolton's answer (5): 6 days, 12 hours, 30 minutes, 40 seconds
Seconds : 604780
    Full - function: 6 days, 23 hours, 59 minutes, 40 seconds
    Full -    class: 6 days, 23 hours, 59 minutes and 40 seconds
    Granularity   this   answer (1): 1 week
    Granularity Bolton's answer (1): 6 days
    Granularity   this   answer (2): 1 week
    Granularity Bolton's answer (2): 6 days, 23 hours
    Granularity   this   answer (3): 1 week
    Granularity Bolton's answer (3): 6 days, 23 hours, 59 minutes
    Granularity   this   answer (4): 6 days, 23 hours, 59 minutes and 40 seconds
    Granularity Bolton's answer (4): 6 days, 23 hours, 59 minutes, 40 seconds
    Granularity   this   answer (5): 6 days, 23 hours, 59 minutes and 40 seconds
    Granularity Bolton's answer (5): 6 days, 23 hours, 59 minutes, 40 seconds
Seconds : 2419180
    Full - function: 3 weeks, 6 days, 23 hours, 59 minutes, 40 seconds
    Full -    class: 3 weeks, 6 days, 23 hours, 59 minutes and 40 seconds
    Granularity   this   answer (1): 4 weeks
    Granularity Bolton's answer (1): 3 weeks
    Granularity   this   answer (2): 4 weeks
    Granularity Bolton's answer (2): 3 weeks, 6 days
    Granularity   this   answer (3): 4 weeks
    Granularity Bolton's answer (3): 3 weeks, 6 days, 23 hours
    Granularity   this   answer (4): 4 weeks
    Granularity Bolton's answer (4): 3 weeks, 6 days, 23 hours, 59 minutes
    Granularity   this   answer (5): 3 weeks, 6 days, 23 hours, 59 minutes and 40 seconds
    Granularity Bolton's answer (5): 3 weeks, 6 days, 23 hours, 59 minutes, 40 seconds
Seconds : 113478160
    Full - function: 187 weeks, 4 days, 9 hours, 42 minutes, 40 seconds
    Full -    class: 187 weeks, 4 days, 9 hours, 42 minutes and 40 seconds
    Granularity   this   answer (1): 188 weeks
    Granularity Bolton's answer (1): 187 weeks
    Granularity   this   answer (2): 187 weeks and 4 days
    Granularity Bolton's answer (2): 187 weeks, 4 days
    Granularity   this   answer (3): 187 weeks, 4 days and 10 hours
    Granularity Bolton's answer (3): 187 weeks, 4 days, 9 hours
    Granularity   this   answer (4): 187 weeks, 4 days, 9 hours and 43 minutes
    Granularity Bolton's answer (4): 187 weeks, 4 days, 9 hours, 42 minutes
    Granularity   this   answer (5): 187 weeks, 4 days, 9 hours, 42 minutes and 40 seconds
    Granularity Bolton's answer (5): 187 weeks, 4 days, 9 hours, 42 minutes, 40 seconds

I have a french translation ready. But it's fast to do the translation ... just few words. Hope this could help as the other answer help me a lot.

How to print matched regex pattern using awk?

gawk can get the matching part of every line using this as action:

{ if (match($0,/your regexp/,m)) print m[0] }

match(string, regexp [, array]) If array is present, it is cleared, and then the zeroth element of array is set to the entire portion of string matched by regexp. If regexp contains parentheses, the integer-indexed elements of array are set to contain the portion of string matching the corresponding parenthesized subexpression.

How can I check if a string contains a character in C#?

Use the function String.Contains();

an example call,

abs.Contains("s"); // to look for lower case s

here is more from MSDN.

How to write "not in ()" sql query using join

I would opt for NOT EXISTS in this case.

SELECT D1.ShortCode
FROM Domain1 D1
    (SELECT 'X'
     FROM Domain2 D2
     WHERE D2.ShortCode = D1.ShortCode

Delete specific line number(s) from a text file using sed?

You can delete a particular single line with its line number by

sed -i '33d' file

This will delete the line on 33 line number and save the updated file.

Can not deserialize instance of java.lang.String out of START_ARRAY token

The error is:

Can not deserialize instance of java.lang.String out of START_ARRAY token at [Source: line: 1, column: 1095] (through reference chain: JsonGen["platforms"])

In JSON, platforms look like this:

"platforms": [
        "platform": "iphone"
        "platform": "ipad"
        "platform": "android_phone"
        "platform": "android_tablet"

So try change your pojo to something like this:

private List platforms;

public List getPlatforms(){
    return this.platforms;

public void setPlatforms(List platforms){
    this.platforms = platforms;

EDIT: you will need change mobile_networks too. Will look like this:

private List mobile_networks;

public List getMobile_networks() {
    return mobile_networks;

public void setMobile_networks(List mobile_networks) {
    this.mobile_networks = mobile_networks;

commands not found on zsh

My solution:

Change back to bash:

source .bashrc


echo $PATH

copy this:


back to the zsh:

source .zsh

open .zshrc:

and paste:

 export PATH=/home/frank/.asdf/shims:/home/frank/....

restart terminal

error TS2339: Property 'x' does not exist on type 'Y'

The correct fix is to add the property in the type definition as explained in @Nitzan Tomer's answer. If that's not an option though:

(Hacky) Workaround 1

You can assign the object to a constant of type any, then call the 'non-existing' property.

const newObj: any = oldObj;
return newObj.someProperty;

You can also cast it as any:

return (oldObj as any).someProperty;

This fails to provide any type safety though, which is the point of TypeScript.

(Hacky) Workaround 2

Another thing you may consider, if you're unable to modify the original type, is extending the type like so:

interface NewType extends OldType {
  someProperty: string;

Now you can cast your variable as this NewType instead of any. Still not ideal but less permissive than any, giving you more type safety.

return (oldObj as NewType).someProperty;

How can I run a PHP script inside a HTML file?

Yes, you can run PHP in an HTML page.

I have successfully executed PHP code in my HTML files for many years. (For the curious, this is because I have over 8,000 static HTML files created by me and others over the last 20 years and I didn't want to lose search engine ranking by changing them and, more importantly, I have too many other things to work on).

I am not an expert -- below is what I've tried and what works for me. Please don't ask me to explain it.

Everything below involves adding a line or two to your .htaccess file.

Here is what one host ( ) support did for me in 2008 -- but it no longer works for me now.

AddHandler application/x-httpd-php5 .html .htm
AddType application/x-httpd-php5 .htm .html

That solution appears to be deprecated now, though it might work for you.

Here's what's working for me now:

AddType application/x-httpd-lsphp .htm .html

(This page has PHP code that executes properly with the above solution -- )

Below are other solutions I found -- they are NOT MINE:

I'm seeing this across many servers I've recently upgraded to EA4. Using cPanel Apache handlers or adding this directly in to .htaccess (same as cPanel does through gui add handlers):

AddHandler application/x-httpd-php5 .html

Sep 9, 2016

AddHandler application/x-httpd-ea-php56 .html

Open a text editor such as wordpad, notepad, nano, etc. and add the following line:

AddHandler x-mapp-php5 .html .htm

If you want to use PHP 5.4 instead of PHP 5.2 then use the following line instead:

AddHandler x-mapp-php6 .html .htm

To run HTML using FastCGI/PHP, try adding this code to the .htaccess file for the directory the script is in:

Options +ExecCGI
AddHandler fcgid-script .html
FCGIWrapper /usr/local/cpanel/cgi-sys/php5 .html

You can add additional lines for other file extensions if needed.

Creating NSData from NSString in Swift

Swift 4.2

let data = .utf8, allowLossyConversion: true)

Print the stack trace of an exception

The Throwable class provides two methods named printStackTrace, one that accepts a PrintWriter and one that takes in a PrintStream, that outputs the stack trace to the given stream. Consider using one of these.

Get data from JSON file with PHP

Use json_decode to transform your JSON into a PHP array. Example:

$json = '{"a":"b"}';
$array = json_decode($json, true);
echo $array['a']; // b

html form - make inputs appear on the same line

use table

<table align="center" width="100%" cellpadding="0" cellspacing="0" border="0"> 
<td><label for="First_Name">First Name:</label></td>
<td><input name="first_name" id="First_Name" type="text" /></td>
<td><label for="last_name">Last Name:</label></td> <td> 
<input name="last_name" id="Last_Name" type="text" /></td> 
<td colspan="2"><label for="Email">Email:</label></td> 
<td colspan="2"><input name="email" id="Email" type="email" /></td> 
<td colspan="4"><input type="submit" value="Submit"/></td> 

WAMP Server doesn't load localhost

Change the port 80 to port 8080 and restart all services and access like localhost:8080/

It will work fine.

python requests get cookies

If you need the path and thedomain for each cookie, which get_dict() is not exposes, you can parse the cookies manually, for instance:

    {'name':, 'value': c.value, 'domain': c.domain, 'path': c.path}
    for c in session.cookies

How to get the index of an item in a list in a single step?

If anyone wonders for the Array version, it goes like this:

int i = Array.FindIndex(yourArray, x => x == itemYouWant);

HTML5 event handling(onfocus and onfocusout) using angular 2

The solution is this:

  <input (click)="focusOut()" type="text" matInput [formControl]="inputControl"
   <mat-autocomplete #auto="matAutocomplete" [displayWith]="displayFn" >
     <mat-option (onSelectionChange)="submitValue($event)" *ngFor="let option of 
      options | async" [value]="option">
      {{ | translate}}

focusOut() {

Automatically get loop index in foreach loop in Perl

Well, there is this way:

use List::Rubyish;

$list = List::Rubyish->new( [ qw<a b c> ] );
$list->each_index( sub { say "\$_=$_" } );

See List::Rubyish.

Select elements by attribute

if (!$("#element").attr('my_attr')){
  //return false
  //attribute doesn't exists

Styling of Select2 dropdown select boxes

Here is a working example of above. Now select2 has been updated the classes have change may be why you cannot get it to work. Here is the css....

    width: 148px !important;

.select2-container--default .select2-selection--single{
    height: 37px;
    width: 148px; 
    font-size: 1.2em;  
    position: relative;

.select2-container--default .select2-selection--single .select2-selection__arrow {
    background-image: -khtml-gradient(linear, left top, left bottom, from(#424242), to(#030303));
    background-image: -moz-linear-gradient(top, #424242, #030303);
    background-image: -ms-linear-gradient(top, #424242, #030303);
    background-image: -webkit-gradient(linear, left top, left bottom, color-stop(0%, #424242), color-stop(100%, #030303));
    background-image: -webkit-linear-gradient(top, #424242, #030303);
    background-image: -o-linear-gradient(top, #424242, #030303);
    background-image: linear-gradient(#424242, #030303);
    width: 40px;
    color: #fff;
    font-size: 1.3em;
    padding: 4px 12px;
    height: 27px;
    position: absolute;
    top: 0px;
    right: 0px;
    width: 20px;

SQL MAX of multiple columns?


SELECT 1, '20000101', '20010101','20020101',100 UNION ALL
SELECT 2, '20000101', '19900101','19980101',99 

SELECT Number,
       Cost  ,
       (SELECT MAX([Date])
       FROM    (SELECT Date1 AS [Date]
               UNION ALL
               SELECT Date2
               UNION ALL
               SELECT Date3
       [Most Recent Date]
FROM   @TableName

how to update spyder on anaconda

To expand on juanpa.arrivillaga's comment:

If you want to update Spyder in the root environment, then conda update spyder works for me.

If you want to update Spyder for a virtual environment you have created (e.g., for a different version of Python), then conda update -n $ENV_NAME spyder where $ENV_NAME is your environment name.

EDIT: In case conda update spyder isn't working, this post indicates you might need to run conda update anaconda before updating spyder. Also note that you can specify an exact spyder version if you want.

Adding div element to body or document in JavaScript

You can make your div HTML code and set it directly into body(Or any element) with following code:

var divStr = '<div class="text-warning">Some html</div>';
document.getElementsByTagName('body')[0].innerHTML += divStr;

How do I read image data from a URL in Python?

For those doing some sklearn/numpy post processing (i.e. Deep learning) you can wrap the PIL object with np.array(). This might save you from having to Google it like I did:

from PIL import Image
import requests
import numpy as np
from StringIO import StringIO

response = requests.get(url)
img = np.array(

Razor view engine - How can I add Partial Views

If you don't want to duplicate code, and like me you just want to show stats, in your view model, you could just pass in the models you want to get data from like so:

public class GameViewModel
    public virtual Ship Ship { get; set; }
    public virtual GamePlayer GamePlayer { get; set; }     

Then, in your controller just run your queries on the respective models, pass them to the view model and return it, example:

GameViewModel PlayerStats = new GameViewModel();

GamePlayer currentPlayer = (from c in db.GamePlayer [more queries]).FirstOrDefault();

[code to check if results]

//pass current player into custom view model
PlayerStats.GamePlayer = currentPlayer;

Like I said, you should only really do this if you want to display stats from the relevant tables, and there's no other part of the CRUD process happening, for security reasons other people have mentioned above.

How to delete an SMS from the inbox in Android programmatically?

public boolean deleteSms(String smsId) {
    boolean isSmsDeleted = false;
    try {
        mActivity.getContentResolver().delete(Uri.parse("content://sms/" + smsId), null, null);
        isSmsDeleted = true;

    } catch (Exception ex) {
        isSmsDeleted = false;
    return isSmsDeleted;

use this permission in AndroidManifiest

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

Replace "\\" with "\" in a string in C#

string a = @"a\\b";
a = a.Replace(@"\\",@"\");

should work. Remember that in the watch Visual STudio show the "\" escaped so you see "\" in place of a single one.

How does one use glide to download an image into a bitmap?

Kotlin's way -

fun Context.bitMapFromImgUrl(imageUrl: String, callBack: (bitMap: Bitmap) -> Unit) {
        .into(object : CustomTarget<Bitmap>() {
            override fun onResourceReady(resource: Bitmap, transition: Transition<in Bitmap>?) {

            override fun onLoadCleared(placeholder: Drawable?) {
                // this is called when imageView is cleared on lifecycle call or for
                // some other reason.
                // if you are referencing the bitmap somewhere else too other than this imageView
                // clear it here as you can no longer have the bitmap

Xcode "Device Locked" When iPhone is unlocked

My problem was I was trying to install on an unsupported (new) iOS version which produced the same errors. Specifically Xcode 11.7 to iOS 14

A connection was successfully established with the server, but then an error occurred during the pre-login handshake

For me I had this happen on a HyperV virtual machine that was accessing my database on my local (host) machine. Basically it all works normally, but after a reboot there is some weird condition that this error starts coming up from the virtual machine applications. There is something in the network layer that is getting horribly confused. However, I have found if I ping the virtual server from the host server, it seems to fix the problem (not sure why exactly). But this might help someone.

Redirect from web api post action


public HttpResponseMessage Post()
    // ... do the job

    // now redirect
    var response = Request.CreateResponse(HttpStatusCode.Moved);
    response.Headers.Location = new Uri("");
    return response;

Failed linking file resources

This might be useful for someone who is looking for a different answer. Go to the Gradle Panel and select your module -> Task -> Verification -> Check. This will check the project for errors and will print the log where the error occurs. Most of the time this Kind of error must be a typo present in your XML file of your project

How to create a new column in a select query

SELECT field1, 
       'example' AS newfield

This will add a column called "newfield" to the output, and its value will always be "example".

Upload files with HTTPWebrequest (multipart/form-data)

For me, the following works (mostly inspirated from all of the following answers), I started from Elad's answer and modify/simplify things to match my need (remove not file form inputs, only one file, ...).

Hope it can helps somebody :)

(PS: I know that exception handling is not implemented and it assumes that it was written inside a class, so I may need some integration effort...)

private void uploadFile()
        Random rand = new Random();
        string boundary = "----boundary" + rand.Next().ToString();
        Stream data_stream;
        byte[] header = System.Text.Encoding.ASCII.GetBytes("\r\n--" + boundary + "\r\nContent-Disposition: form-data; name=\"file_path\"; filename=\"" + System.IO.Path.GetFileName(this.file) + "\"\r\nContent-Type: application/octet-stream\r\n\r\n");
        byte[] trailer = System.Text.Encoding.ASCII.GetBytes("\r\n--" + boundary + "--\r\n");

        // Do the request
        HttpWebRequest request = (HttpWebRequest)WebRequest.Create(MBF_URL);
        request.UserAgent = "My Toolbox";
        request.Method = "POST";
        request.KeepAlive = true;
        request.ContentType = "multipart/form-data; boundary=" + boundary;
        data_stream = request.GetRequestStream();
        data_stream.Write(header, 0, header.Length);
        byte[] file_bytes = System.IO.File.ReadAllBytes(this.file);
        data_stream.Write(file_bytes, 0, file_bytes.Length);
        data_stream.Write(trailer, 0, trailer.Length);

        // Read the response
        WebResponse response = request.GetResponse();
        data_stream = response.GetResponseStream();
        StreamReader reader = new StreamReader(data_stream);
        this.url = reader.ReadToEnd();

        if (this.url == "") { this.url = "No response :("; }


Foreign key constraint may cause cycles or multiple cascade paths?

SQL Server does simple counting of cascade paths and, rather than trying to work out whether any cycles actually exist, it assumes the worst and refuses to create the referential actions (CASCADE): you can and should still create the constraints without the referential actions. If you can't alter your design (or doing so would compromise things) then you should consider using triggers as a last resort.

FWIW resolving cascade paths is a complex problem. Other SQL products will simply ignore the problem and allow you to create cycles, in which case it will be a race to see which will overwrite the value last, probably to the ignorance of the designer (e.g. ACE/Jet does this). I understand some SQL products will attempt to resolve simple cases. Fact remains, SQL Server doesn't even try, plays it ultra safe by disallowing more than one path and at least it tells you so.

Microsoft themselves advises the use of triggers instead of FK constraints.

Limit Decimal Places in Android EditText

et = (EditText) vw.findViewById(;

et.setFilters(new InputFilter[] {
        new DigitsKeyListener(Boolean.FALSE, Boolean.TRUE) {
            int beforeDecimal = 5, afterDecimal = 2;

            public CharSequence filter(CharSequence source, int start, int end,
                    Spanned dest, int dstart, int dend) {
                String temp = et.getText() + source.toString();

                if (temp.equals(".")) {
                    return "0.";
                else if (temp.toString().indexOf(".") == -1) {
                    // no decimal point placed yet
                    if (temp.length() > beforeDecimal) {
                        return "";
                } else {
                    temp = temp.substring(temp.indexOf(".") + 1);
                    if (temp.length() > afterDecimal) {
                        return "";

                return super.filter(source, start, end, dest, dstart, dend);

Postgresql: password authentication failed for user "postgres"

This was frustrating, most of the above answers are correct but they fail to mention you have to restart the database service before the changes in the pg_hba.conf file will take affect.

so if you make the changes as mentioned above:

local all postgres ident

then restart as root ( on centos its something like service service postgresql-9.2 restart ) now you should be able to access the db as the user postgres

psql (9.2.4)
Type "help" for help.


Hope this adds info for new postgres users

Create two threads, one display odd & other even numbers

Yes it is fine. But in this case, I don't think you need 2 threads are all, because the operation is simple. However, if you are practicing threads, it is OK

Add and remove a class on click using jQuery?

Why not try something like this?

$('#menu li a').on('click', function(){
    $('#menu li a.current').removeClass('current');


iOS Swift - Get the Current Local Time and Date Timestamp

If you just want the unix timestamp, create an extension:

extension Date {
    func currentTimeMillis() -> Int64 {
        return Int64(self.timeIntervalSince1970 * 1000)

Then you can use it just like in other programming languages:

let timestamp = Date().currentTimeMillis()

Jackson JSON custom serialization for certain fields

You can create a custom serializer inline in the mixin. Then annotate a field with it. See example below that appends " - something else " to lang field. This is kind of hackish - if your serializer requires something like a repository or anything injected by spring, this is going to be a problem. Probably best to use a custom deserializer/serializer instead of a mixin.

package com.test;

import com.fasterxml.jackson.annotation.JsonAutoDetect;
import com.fasterxml.jackson.annotation.JsonAutoDetect.Visibility;
import com.fasterxml.jackson.annotation.JsonProperty;
import com.fasterxml.jackson.annotation.JsonPropertyOrder;
import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.JsonSerializer;
import com.fasterxml.jackson.databind.SerializerProvider;
import com.fasterxml.jackson.databind.annotation.JsonSerialize;
import com.test.Argument;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
//Serialize only fields explicitly mentioned by this mixin.
    fieldVisibility = Visibility.NONE,
    setterVisibility = Visibility.NONE,
    getterVisibility = Visibility.NONE,
    isGetterVisibility = Visibility.NONE,
    creatorVisibility = Visibility.NONE
@JsonPropertyOrder({"lang", "name", "value"})
public abstract class V2ArgumentMixin {

  private String name;

  @JsonSerialize(using = LangCustomSerializer.class, as=String.class)
  private String lang;

  private Object value;

  public static class LangCustomSerializer extends JsonSerializer<String> {

    public void serialize(String value,
                          JsonGenerator jsonGenerator,
                          SerializerProvider serializerProvider)
        throws IOException, JsonProcessingException {
      jsonGenerator.writeObject(value.toString() + "  - something else");

Add hover text without javascript like we hover on a user's reputation

Use the title attribute, for example:

<div title="them's hoverin' words">hover me</div>


<span title="them's hoverin' words">hover me</span>

System.Net.WebException HTTP status code

I'm not sure if there is but if there was such a property it wouldn't be considered reliable. A WebException can be fired for reasons other than HTTP error codes including simple networking errors. Those have no such matching http error code.

Can you give us a bit more info on what you're trying to accomplish with that code. There may be a better way to get the information you need.

How to check date of last change in stored procedure or function in SQL server

I found this listed as the new technique

This is very detailed

order by  LAST_ALTERED desc

order by  CREATED desc 

order by  LAST_ALTERED desc

order by  CREATED desc 

Opening a CHM file produces: "navigation to the webpage was canceled"

Win 8 x64:

just move it to another folder or rename your folder (in my case: my folder was "c#"). avoid to use symbol on folder name. name it with letter.


MySQL : ERROR 1215 (HY000): Cannot add foreign key constraint

Just add 'unsigned' for the FOREIGN constraint

`FK` int(11) unsigned DEFAULT NULL,

What is the correct format to use for Date/Time in an XML file

The XmlConvert class provides these kinds of facilities. About DateTimes, in particular, be careful about obsolete methods. See also:

How can I make the browser wait to display the page until it's fully loaded?

Although this is not always a good idea, you're free to decide if you really want to do that. There are some different ways to do it, and I found a simple example here:

Probably not the best one, but it should help you develop your own solution. Good luck.

"Templates can be used only with field access, property access, single-dimension array index, or single-parameter custom indexer expressions" error

Fill in the service layer with the model and then send it to the view. For example: ViewItem=ModelItem.ToString().Substring(0,100);

How to get the current branch name in Git?

You can permanently set up your bash output to show your git-branch name. It is very handy when you work with different branches, no need to type $ git status all the time. Github repo git-aware-prompt .

Open your terminal (ctrl-alt-t) and enter the commands

mkdir ~/.bash
cd ~/.bash
git clone git://

Edit your .bashrc with sudo nano ~/.bashrc command (for Ubuntu) and add the following to the top:

export GITAWAREPROMPT=~/.bash/git-aware-prompt

Then paste the code

export PS1="\${debian_chroot:+(\$debian_chroot)}\[\033[01;32m\]\u@\h\[\033[00m\]:\[\033[01;34m\]\w\[\033[00m\] \[$txtcyn\]\$git_branch\[$txtred\]\$git_dirty\[$txtrst\]\$ "

at the end of the same file you pasted the installation code into earlier. This will give you the colorized output:enter image description here

select2 changing items dynamically

For v4 this is a known issue that won't be addressed in 4.0 but there is a workaround. Check

What is the difference between tinyint, smallint, mediumint, bigint and int in MySQL?

Those seem to be MySQL data types.

According to the documentation they take:

  1. tinyint = 1 byte
  2. smallint = 2 bytes
  3. mediumint = 3 bytes
  4. int = 4 bytes
  5. bigint = 8 bytes

And, naturally, accept increasingly larger ranges of numbers.

What is $@ in Bash?

Yes. Please see the man page of bash ( the first thing you go to ) under Special Parameters

Special Parameters

The shell treats several parameters specially. These parameters may only be referenced; assignment to them is not allowed.

* Expands to the positional parameters, starting from one. When the expansion occurs within double quotes, it expands to a single word with the value of each parameter separated by the first character of the IFS special variable. That is, "$*" is equivalent to "$1c$2c...", where c is the first character of the value of the IFS variable. If IFS is unset, the parameters are separated by spaces. If IFS is null, the parameters are joined without intervening separators.

@ Expands to the positional parameters, starting from one. When the expansion occurs within double quotes, each parameter expands to a separate word. That is, "$@" is equivalent to "$1" "$2" ... If the double-quoted expansion occurs within a word, the expansion of the first parameter is joined with the beginning part of the original word, and the expansion of the last parameter is joined with the last part of the original word. When there are no positional parameters, "$@" and $@ expand to nothing (i.e., they are removed).

How can I select records ONLY from yesterday?

trunc(tran_date) = trunc(sysdate -1)

Change x axes scale in matplotlib

I find the simple solution


nvm keeps "forgetting" node in new terminal session

If you have tried everything still no luck you can try this :_

1 -> Uninstall NVM

rm -rf ~/.nvm

2 -> Remove npm dependencies by following this

3 -> Install NVM

curl -o- | bash

4 -> Set ~/.bash_profile configuration

Run sudo nano ~/.bash_profile

Copy and paste following this

export NVM_DIR="$HOME/.nvm"
[ -s "$NVM_DIR/" ] && \. "$NVM_DIR/"  # This loads nvm
[ -s "$NVM_DIR/bash_completion" ] && \. "$NVM_DIR/bash_completion"  # This loads nvm bash_completion

5 -> CONTROL + X save the changes

6 -> Run . ~/.bash_profile

7 -> Now you should have nvm installed on your machine, to install node run nvm install v7.8.0 this will be default node version or you can install any version of node

How do I kill all the processes in Mysql "show processlist"?

Query 1 select concat('KILL ',id,';') from information_schema.processlist where user='username' into outfile '/tmp/a.txt';

Query 2 source a.txt

This will enable you to kill all the queries in show processlist by specific user.

Append key/value pair to hash with << in Ruby

I had to do a similar thing but I needed to add values with same keys. When I use merge or update I can't push values with same keys. So I had to use array of hashes.

    my_hash_static = {:header =>{:company => 'xx', :usercode => 'xx', :password => 'xx',
                      :type=> 'n:n', :msgheader => from}, :body=>[]}
    my_hash_dynamic = {:mp=>{:msg=>message, :no=>phones} }        
    my_hash_full = my_hash_static[:body].push my_hash_dynamic

C# Convert List<string> to Dictionary<string, string>


another way to deal with duplicate is you can do like this

var dic = slist.Select((element, index)=> new{element,index} )
            .ToDictionary(ele=>ele.index.ToString(), ele=>ele.element);


easy way to do is

var res = list.ToDictionary(str => str, str=> str); 

but make sure that there is no string is repeating...again otherewise above code will not work for you

if there is string is repeating than its better to do like this

Dictionary<string,string> dic= new Dictionary<string,string> ();

    foreach(string s in Stringlist)
        //  dic.Add( value to dictionary

What are the differences between a program and an application?

Without more information about the question, the terms 'program' and 'application' are nearly synonymous.

As Saif has indicated, 'application' tends to be used more for non-system related programs. That being said, I don't think it's wrong to describe the operating system as an special application that provides an environment in which to run other applications.

ORA-30926: unable to get a stable set of rows in the source tables

A further clarification to the use of DISTINCT to resolve error ORA-30926 in the general case:

You need to ensure that the set of data specified by the USING() clause has no duplicate values of the join columns, i.e. the columns in the ON() clause.

In OP's example where the USING clause only selects a key, it was sufficient to add DISTINCT to the USING clause. However, in the general case the USING clause may select a combination of key columns to match on and attribute columns to be used in the UPDATE ... SET clause. Therefore in the general case, adding DISTINCT to the USING clause will still allow different update rows for the same keys, in which case you will still get the ORA-30926 error.

This is an elaboration of DCookie's answer and point 3.1 in Tagar's answer, which from my experience may not be immediately obvious.

Converting Swagger specification JSON to HTML documentation

See the swagger-api/swagger-codegen project on GitHub ; the project README shows how to use it to generate static HTML. See Generating static html api documentation.

If you want to view the swagger.json you can install the Swagger UI and run it. You just deploy it on a web server (the dist folder after you clone the repo from GitHub) and view the Swagger UI in your browser. It's a JavaScript app.

Is there a way to specify a default property value in Spring XML?

Are you looking for the PropertyOverrideConfigurer documented here

The PropertyOverrideConfigurer, another bean factory post-processor, is similar to the PropertyPlaceholderConfigurer, but in contrast to the latter, the original definitions can have default values or no values at all for bean properties. If an overriding Properties file does not have an entry for a certain bean property, the default context definition is used.

jQuery prevent change for select

Try this:

var my_condition = true;
var lastSel = $("#my_select option:selected");

    lastSel.prop("selected", true);

    lastSel = $("#my_select option:selected");

How do I find the index of a character within a string in C?

This should do it:

//Returns the index of the first occurence of char c in char* string. If not found -1 is returned.
int get_index(char* string, char c) {
    char *e = strchr(string, c);
    if (e == NULL) {
        return -1;
    return (int)(e - string);

Running PHP script from the command line

On SuSE, there are two different configuration files for PHP: one for Apache, and one for CLI (command line interface). In the /etc/php5/ directory, you will find an "apache2" directory and a "cli" directory. Each has a "php.ini" file. The files are for the same purpose (php configuration), but apply to the two different ways of running PHP. These files, among other things, load the modules PHP uses.

If your OS is similar, then these two files are probably not the same. Your Apache php.ini is probably loading the gearman module, while the cli php.ini isn't. When the module was installed (auto or manual), it probably only updated the Apache php.ini file.

You could simply copy the Apache php.ini file over into the cli directory to make the CLI environment exactly like the Apache environment.

Or, you could find the line that loads the gearman module in the Apache file and copy/paste just it to the CLI file.

Specifying java version in maven - differences between properties and compiler plugin

None of the solutions above worked for me straight away. So I followed these steps:

  1. Add in pom.xml:
  1. Go to Project Properties > Java Build Path, then remove the JRE System Library pointing to JRE1.5.

  2. Force updated the project.

How to get size in bytes of a CLOB column in Oracle?

It only works till 4000 byte, What if the clob is bigger than 4000 bytes then we use this

v_clob_size clob;


      v_clob_size:= (DBMS_LOB.getlength(v_clob)) / 1024 / 1024;
      DBMS_OUTPUT.put_line('CLOB Size   ' || v_clob_size);   


select (DBMS_LOB.getlength(your_column_name))/1024/1024 from your_table

AngularJS: How to make angular load script inside ng-include?

I tried using Google reCAPTCHA explicitly. Here is the example:

// put somewhere in your index.html
<script type="text/javascript">
var onloadCallback = function() {
  grecaptcha.render('your-recaptcha-element', {
    'sitekey' : '6Ldcfv8SAAAAAB1DwJTM6T7qcJhVqhqtss_HzS3z'

//link function of Angularjs directive
link: function (scope, element, attrs) {
  var domElem = '<script src="" async defer></script>';

PHP mail function doesn't complete sending of e-mail

For those who do not want to use external mailers and want to mail() on a dedicated Linux server.

The way, how PHP mails, is described in php.ini in section [mail function].

Parameter sendmail-path describes how sendmail is called. The default value is sendmail -t -i, so if you get a working sendmail -t -i < message.txt in the Linux console - you will be done. You could also add mail.log to debug and be sure mail() is really called.

Different MTAs can implement sendmail. They just make a symbolic link to their binaries on that name. For example, in Debian the default is Postfix. Configure your MTA to send mail and test it from the console with sendmail -v -t -i < message.txt. File message.txt should contain all headers of a message and a body, destination address for the envelope will be taken from the To: header. Example:

From: [email protected]
To: [email protected]
Subject: Test mail via sendmail.

Text body.

I prefer to use ssmtp as MTA because it is simple and does not require running a daemon with opened ports. ssmtp fits only for sending mail from localhost. It also can send authenticated email via your account on a public mail service. Install ssmtp and edit configuration file /etc/ssmtp/ssmtp.conf. To be able also to receive local system mail to Unix accounts (alerts to root from cron jobs, for example) configure /etc/ssmtp/revaliases file.

Here is my configuration for my account on Yandex mail:

[email protected]
[email protected]

Detect HTTP or HTTPS then force HTTPS in JavaScript

You should check this:

Add this meta tag to your index.html inside head

<meta http-equiv="Content-Security-Policy" content="upgrade-insecure-requests">

Hope it helped.

How do I print the content of httprequest request?

This should be more helpful for debug. Answer from @Juned Ahsan will not specify full URL and will not print multiple headers/parameters.

private String httpServletRequestToString(HttpServletRequest request) {
    StringBuilder sb = new StringBuilder();

    sb.append("Request Method = [" + request.getMethod() + "], ");
    sb.append("Request URL Path = [" + request.getRequestURL() + "], ");

    String headers =
            .map(headerName -> headerName + " : " + Collections.list(request.getHeaders(headerName)) )
            .collect(Collectors.joining(", "));

    if (headers.isEmpty()) {
        sb.append("Request headers: NONE,");
    } else {
        sb.append("Request headers: ["+headers+"],");

    String parameters =
            .map(p -> p + " : " + Arrays.asList( request.getParameterValues(p)) )
            .collect(Collectors.joining(", "));             

    if (parameters.isEmpty()) {
        sb.append("Request parameters: NONE.");
    } else {
        sb.append("Request parameters: [" + parameters + "].");

    return sb.toString();

Laravel 4: how to "order by" using Eloquent ORM

If you are using post as a model (without dependency injection), you can also do:

$posts = Post::orderBy('id', 'DESC')->get();

Can't connect to local MySQL server through socket '/var/mysql/mysql.sock' (38)

I've deleted mysql.sock file and it worked. Putting the rights on it didn't work at all. Neither restarting, or whatever ...

Java Array, Finding Duplicates

Print all the duplicate elements. Output -1 when no repeating elements are found.

import java.util.*;

public class PrintDuplicate {

    public static void main(String args[]){
        HashMap<Integer,Integer> h = new HashMap<Integer,Integer>();

        Scanner s=new Scanner(;
        int ii=s.nextInt();
        int k=s.nextInt();
        int[] arr=new  int[k];
        int[] arr1=new  int[k];
        int l=0;
        for(int i=0; i<arr.length; i++)
        for(int i=0; i<arr.length; i++){
                h.put(arr[i], h.get(arr[i]) + 1);
            } else {
                h.put(arr[i], 1);
            for(int i=0;i<l;i++)

Insert array into MySQL database with PHP

$columns = implode(", ",array_keys($data));
$escaped_values = array_map(array($con, 'real_escape_string'),array_values($data));
$values  = implode("', '", $escaped_values);
return $sql = "INSERT INTO `reservations`($columns) VALUES ('$values')";

This is improvement to the solution given by Shiplu Mokaddim

Checking to see if a DateTime variable has had a value assigned

The only way of having a variable which hasn't been assigned a value in C# is for it to be a local variable - in which case at compile-time you can tell that it isn't definitely assigned by trying to read from it :)

I suspect you really want Nullable<DateTime> (or DateTime? with the C# syntactic sugar) - make it null to start with and then assign a normal DateTime value (which will be converted appropriately). Then you can just compare with null (or use the HasValue property) to see whether a "real" value has been set.

Smart way to truncate long strings

c_harm's answer is in my opinion the best. Please note that if you want to use

"My string".truncate(n)

you will have to use a regexp object constructor rather than a literal. Also you'll have to escape the \S when converting it.

String.prototype.truncate =
        var p  = new RegExp("^.{0," + n + "}[\\S]*", 'g');
        var re = this.match(p);
        var l  = re[0].length;
        var re = re[0].replace(/\s$/,'');

        if (l < this.length) return re + '&hellip;';

Get java.nio.file.Path object from

Yes, you can get it from the File object by using File.toPath(). Keep in mind that this is only for Java 7+. Java versions 6 and below do not have it.

How to get an object's property's value by property name?

Expanding upon @aquinas:

Get-something | select -ExpandProperty PropertyName


Get-something | select -expand PropertyName


Get-something | select -exp PropertyName

I made these suggestions for those that might just be looking for a single-line command to obtain some piece of information and wanted to include a real-world example.

In managing Office 365 via PowerShell, here was an example I used to obtain all of the users/groups that had been added to the "BookInPolicy" list:

Get-CalendarProcessing [email protected] | Select -expand BookInPolicy

Just using "Select BookInPolicy" was cutting off several members, so thank you for this information!

How to secure an ASP.NET Web API

If you want to secure your API in a server to server fashion (no redirection to website for 2 legged authentication). You can look at OAuth2 Client Credentials Grant protocol.

I have developed a library that can help you easily add this kind of support to your WebAPI. You can install it as a NuGet package:

The library targets .NET Framework 4.5.

Once you add the package to your project, it will create a readme file in the root of your project. You can look at that readme file to see how to configure/use this package.


OpenMP set_num_threads() is not working

Try setting your num_threads inside your omp parallel code, it worked for me. This will give output as 4

#pragma omp parallel
   int id = omp_get_num_threads();
   #pragma omp for
   for (i = 0:n){foo(A);}

printf("Number of threads: %d", id);

What is a good Hash Function?

A good hash function should

  1. be bijective to not loose information, where possible, and have the least collisions
  2. cascade as much and as evenly as possible, i.e. each input bit should flip every output bit with probability 0.5 and without obvious patterns.
  3. if used in a cryptographic context there should not exist an efficient way to invert it.

A prime number modulus does not satisfy any of these points. It is simply insufficient. It is often better than nothing, but it's not even fast. Multiplying with an unsigned integer and taking a power-of-two modulus distributes the values just as well, that is not well at all, but with only about 2 cpu cycles it is much faster than the 15 to 40 a prime modulus will take (yes integer division really is that slow).

To create a hash function that is fast and distributes the values well the best option is to compose it from fast permutations with lesser qualities like they did with PCG for random number generation.

Useful permutations, among others, are:

  • multiplication with an uneven integer
  • binary rotations
  • xorshift

Following this recipe we can create our own hash function or we take splitmix which is tested and well accepted.

If cryptographic qualities are needed I would highly recommend to use a function of the sha family, which is well tested and standardised, but for educational purposes this is how you would make one:

First you take a good non-cryptographic hash function, then you apply a one-way function like exponentiation on a prime field or k many applications of (n*(n+1)/2) mod 2^k interspersed with an xorshift when k is the number of bits in the resulting hash.

Javascript negative number

function negative(n) {
  return n < 0;

Your regex should work fine for string numbers, but this is probably faster. (edited from comment in similar answer above, conversion with +n is not needed.)

Does the 'mutable' keyword have any purpose other than allowing the variable to be modified by a const function?

Mutable is used when you have a variable inside the class that is only used within that class to signal things like for example a mutex or a lock. This variable does not change the behaviour of the class, but is necessary in order to implement thread safety of the class itself. Thus if without "mutable", you would not be able to have "const" functions because this variable will need to be changed in all functions that are available to the outside world. Therefore, mutable was introduced in order to make a member variable writable even by a const function.

The mutable specified informs both the compiler and the reader that it is safe and expected that a member variable may be modified within a const member function.

Iterating over every property of an object in javascript using Prototype?

There's no need for Prototype here: JavaScript has loops. If you're not sure that no one messed with Object.prototype, check hasOwnProperty() as well, ie

for(var prop in obj) {

Experimental decorators warning in TypeScript compilation

So it turns out you can get around this by matching your module name to the file name. If you have the module name BankSpecialtyModule then the file name should be. bank-specialty.module.ts

get all the images from a folder in php

You can simply show your actual image directory(less secure). By just 2 line of code.

 $dir = base_url()."photos/";

echo"<a href=".$dir.">Photo Directory</a>";

How to print out a variable in makefile

All versions of make require that command lines be indented with a TAB (not space) as the first character in the line. If you showed us the entire rule instead of just the two lines in question we could give a clearer answer, but it should be something like:

myTarget: myDependencies
        @echo hi

where the first character in the second line must be TAB.

Simple DateTime sql query

Open up the Access File you are trying to export SQL data to. Delete any Queries that are there. Everytime you run SQL Server Import wizard, even if it fails, it creates a Query in the Access DB that has to be deleted before you can run the SQL export Wizard again.

How to change indentation mode in Atom?

Tab Control gives nice control in a similar manner to that described in your question.

Also nice, for JavaScript developers, is ESLint Tab Length for using ESLint config.

Or if you're using an .editorconfig for defining project-specific indentation rules, there is EditorConfig

What is the difference between And and AndAlso in VB.NET?

In addition to the answers above, AndAlso provides a conditioning process known as short circuiting. Many programming languages have this functionality built in like does, and can provide substantial performance increases in long condition statements by cutting out evaluations that are unneccessary.

Another similar condition is the OrElse condition which would only check the right condition if the left condition is false, thus cutting out unneccessary condition checks after a true condition is found.

I would advise you to always use short circuiting processes and structure your conditional statements in ways that can benefit the most by this. For example, test your most efficient and fastest conditions first so that you only run your long conditions when you absolutely have to and short circuit the other times.

How to get controls in WPF to fill available space?

There are also some properties you can set to force a control to fill its available space when it would otherwise not do so. For example, you can say:


... to force the contents of a control to stretch horizontally. Or you can say:


... to force the control itself to stretch horizontally to fill its parent.

How to emulate a do-while loop in Python?

See if this helps :

Set a flag inside the exception handler and check it before working on the s.

flagBreak = false;
while True :

    if flagBreak : break

    if s :
        print s
    try :
        s =
    except StopIteration :
        flagBreak = true

print "done"

How do I check whether an array contains a string in TypeScript?

The same as in JavaScript, using Array.prototype.indexOf():

console.log(channelArray.indexOf('three') > -1);

Or using ECMAScript 2016 Array.prototype.includes():


Note that you could also use methods like showed by @Nitzan to find a string. However you wouldn't usually do that for a string array, but rather for an array of objects. There those methods were more sensible. For example

const arr = [{foo: 'bar'}, {foo: 'bar'}, {foo: 'baz'}];
console.log(arr.find(e => === 'bar')); // {foo: 'bar'} (first match)
console.log(arr.some(e => === 'bar')); // true
console.log(arr.filter(e => === 'bar')); // [{foo: 'bar'}, {foo: 'bar'}]





Short description of the scoping rules?

In Python,

any variable that is assigned a value is local to the block in which the assignment appears.

If a variable can't be found in the current scope, please refer to the LEGB order.

JTable - Selected Row click event

 private void jTable1MouseClicked(java.awt.event.MouseEvent evt) {                                     
     JTable source = (JTable)evt.getSource();
            int row = source.rowAtPoint( evt.getPoint() );
            int column = source.columnAtPoint( evt.getPoint() );
            String s=source.getModel().getValueAt(row, column)+"";

            JOptionPane.showMessageDialog(null, s);


if you want click cell or row in jtable use this way

Does Python have a ternary conditional operator?

As already answered, yes there is a ternary operator in python:

<expression 1> if <condition> else <expression 2>

Additional information:

If <expression 1> is the condition you can use Short-cirquit evaluation:

a = True
b = False

# Instead of this:
x = a if a else b

# You could use Short-cirquit evaluation:
x = a or b

PS: Of course, a Short-cirquit evaluation is not a ternary operator but often the ternary is used in cases where the short circuit would be enough.

TS1086: An accessor cannot be declared in ambient context

In my case, mismatch of version of two libraries.

I am using angular 7.0.0 and installed

"@swimlane/ngx-dnd": "^8.0.0"

and this caused the problem. Reverting this library to

"@swimlane/ngx-dnd": "6.0.0"

worked for me.

What is the difference between using constructor vs getInitialState in React / React Native?

The big difference is start from where they are coming from, so constructor is the constructor of your class in JavaScript, on the other side, getInitialState is part of the lifecycle of React . The constructor method is a special method for creating and initializing an object created with a class.

How to split long commands over multiple lines in PowerShell

Trailing backtick character, i.e.,

&"C:\Program Files\IIS\Microsoft Web Deploy\msdeploy.exe" `
-verb:sync `
-source:contentPath="c:\workspace\xxx\master\Build\_PublishedWebsites\xxx.Web" `

White space matters. The required format is Space`Enter.

Add a list item through javascript

If you want to create a li element for each input/name, then you have to create it, with document.createElement [MDN].

Give the list the ID:

<ol id="demo"></ol>

and get a reference to it:

var list = document.getElementById('demo');

In your event handler, create a new list element with the input value as content and append to the list with Node.appendChild [MDN]:

var firstname = document.getElementById('firstname').value;
var entry = document.createElement('li');


Is there a command line command for verifying what version of .NET is installed

Unfortunately the best way would be to check for that directory. I am not sure what you mean but "actually installed" as .NET 3.5 uses the same CLR as .NET 3.0 and .NET 2.0 so all new functionality is wrapped up in new assemblies that live in that directory. Basically, if the directory is there then 3.5 is installed.

Only thing I would add is to find the dir this way for maximum flexibility:


WPF Datagrid Get Selected Cell Value

Worked For me

object item = dgwLoadItems.SelectedItem;
string ID = (dgwLoadItems.SelectedCells[0].Column.GetCellContent(item) as TextBlock).Text;

Making a UITableView scroll when text field is selected

Solution for Swift 3-4 with animations and keyboard frame changing:

First, create a Bool:

// MARK: - Private Properties
private var isKeyboardShowing = false

Secondly, add Observers to the System Keyboard Notifications:

// MARK: - Overriding ViewController Life Cycle Methods
override func viewWillAppear(_ animated: Bool) {

    NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow), name: .UIKeyboardWillShow, object: nil)

    NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillHide), name: .UIKeyboardWillHide, object: nil)

    NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillChangeFrame), name: .UIKeyboardWillChangeFrame, object: nil)

Thirdly, prepare the animation function:

func adjustTableViewInsets(keyboardHeight: CGFloat, duration: NSNumber, curve: NSNumber){
    var extraHeight: CGFloat = 0
    if keyboardHeight > 0 {
        extraHeight = 20
        isKeyboardShowing = true
    } else {
        isKeyboardShowing = false

    let contentInset = UIEdgeInsets(top: 0, left: 0, bottom: keyboardHeight + extraHeight, right: 0)
    func animateFunc() {
        //refresh constraints
        tableView.contentInset = contentInset

    UIView.animate(withDuration: TimeInterval(duration), delay: 0, options: [UIViewAnimationOptions(rawValue: UInt(curve))], animations: animateFunc, completion: nil)

Then add the target/action methods (called by the observers):

// MARK: - Target/Selector Actions
func keyboardWillShow(notification: NSNotification) {
    if !isKeyboardShowing {
        if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue {
            let keyboardHeight = keyboardSize.height

            let duration = notification.userInfo?[UIKeyboardAnimationDurationUserInfoKey] as! NSNumber
            let curve = notification.userInfo?[UIKeyboardAnimationCurveUserInfoKey] as! NSNumber

            adjustTableViewInsets(keyboardHeight: keyboardHeight, duration: duration, curve: curve)

func keyboardWillHide(notification: NSNotification) {
    let duration = notification.userInfo?[UIKeyboardAnimationDurationUserInfoKey] as! NSNumber
    let curve = notification.userInfo?[UIKeyboardAnimationCurveUserInfoKey] as! NSNumber
    adjustTableViewInsets(keyboardHeight: 0, duration: duration, curve: curve)

func keyboardWillChangeFrame(notification: NSNotification) {
    if isKeyboardShowing {
        let duration = notification.userInfo?[UIKeyboardAnimationDurationUserInfoKey] as! NSNumber
        let curve = notification.userInfo?[UIKeyboardAnimationCurveUserInfoKey] as! NSNumber

        if let newKeyboardSize = (notification.userInfo?[UIKeyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue {
            let keyboardHeight = newKeyboardSize.height
            adjustTableViewInsets(keyboardHeight: keyboardHeight, duration: duration, curve: curve)

Lastly, don't forget to remove observers in deinit or in viewWillDisappear:

deinit {

How can I set the Secure flag on an ASP.NET Session Cookie?

Building upon @Mark D's answer I would use web.config transforms to set all the various cookies to Secure. This includes setting anonymousIdentification cookieRequireSSL and httpCookies requireSSL.

To that end you'd setup your web.Release.config as:

<?xml version="1.0"?>
<configuration xmlns:xdt="">
    <httpCookies xdt:Transform="SetAttributes(httpOnlyCookies)" httpOnlyCookies="true" />
    <httpCookies xdt:Transform="SetAttributes(requireSSL)" requireSSL="true" />
    <anonymousIdentification xdt:Transform="SetAttributes(cookieRequireSSL)" cookieRequireSSL="true" /> 

If you're using Roles and Forms Authentication with the ASP.NET Membership Provider (I know, it's ancient) you'll also want to set the roleManager cookieRequireSSL and the forms requireSSL attributes as secure too. If so, your web.release.config might look like this (included above plus new tags for membership API):

<?xml version="1.0"?>
<configuration xmlns:xdt="">
    <httpCookies xdt:Transform="SetAttributes(httpOnlyCookies)" httpOnlyCookies="true" />
    <httpCookies xdt:Transform="SetAttributes(requireSSL)" requireSSL="true" />
    <anonymousIdentification xdt:Transform="SetAttributes(cookieRequireSSL)" cookieRequireSSL="true" /> 
    <roleManager xdt:Transform="SetAttributes(cookieRequireSSL)" cookieRequireSSL="true" />
        <forms xdt:Transform="SetAttributes(requireSSL)" requireSSL="true" />

Background on web.config transforms here:

Obviously this goes beyond the original question of the OP but if you don't set them all to secure you can expect that a security scanning tool will notice and you'll see red flags appear on the report. Ask me how I know. :)

How to set a header in an HTTP response?

Header fields are not copied to subsequent requests. You should use either cookie for this (addCookie method) or store "REMOTE_USER" in session (which you can obtain with getSession method).

Installing SQL Server 2012 - Error: Prior Visual Studio 2010 instances requiring update

Only install the Service Pack (VS10sp1-KB983509.msp) wasn't enough to me.

I had to uninstall the Visual Studio Team Explorer 2010 to continue the installation :)

Select top 10 records for each category

Might the UNION operator work for you? Have one SELECT for each section, then UNION them together. Guess it would only work for a fixed number of sections though.

What are the special dollar sign shell variables?

To help understand what do $#, $0 and $1, ..., $n do, I use this script:


for ((i=0; i<=$#; i++)); do
  echo "parameter $i --> ${!i}"

Running it returns a representative output:

$ ./ "hello" "how are you" "i am fine"
parameter 0 -->
parameter 1 --> hello
parameter 2 --> how are you
parameter 3 --> i am fine

Test if a vector contains a given element

Both the match() (returns the first appearance) and %in% (returns a Boolean) functions are designed for this.

v <- c('a','b','c','e')

'b' %in% v
## returns TRUE

## returns the first location of 'b', in this case: 2

How to create dispatch queue in Swift 3

You can create dispatch queue using this code in swift 3.0

   /*Write your code here*/

   /* or */

let delayTime = + Double(Int64(0.5 * Double(NSEC_PER_SEC))) / Double(NSEC_PER_SEC)                   
DispatchQueue.main.asyncAfter(deadline: delayTime)
  /*Write your code here*/

What is the largest possible heap size with a 64-bit JVM?

I tried -Xmx32255M is accepted by vmargs for compressed oops.

Same Navigation Drawer in different Activities

package xxxxxx;

import android.content.Context;
import android.content.Intent;
import android.widget.SearchView;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Toast;

public class loginhome extends AppCompatActivity {
    private Toolbar toolbar;
    private NavigationView navigationView;
    private DrawerLayout drawerLayout;

    // Make sure to be using version.
    // The has been deprecated.
    private ActionBarDrawerToggle drawerToggle;

    protected void onCreate(Bundle savedInstanceState) {

        // Initializing Toolbar and setting it as the actionbar
        toolbar = (Toolbar) findViewById(;

        //Initializing NavigationView

        navigationView = (NavigationView) findViewById(;

        //Setting Navigation View Item Selected Listener to handle the item click of the navigation menu
        navigationView.setNavigationItemSelectedListener(new NavigationView.OnNavigationItemSelectedListener() {

            // This method will trigger on item Click of navigation menu

            public boolean onNavigationItemSelected(MenuItem menuItem) {

                //Checking if the item is in checked state or not, if not make it in checked state
                if(menuItem.isChecked()) menuItem.setChecked(false);
                else menuItem.setChecked(true);

                //Closing drawer on item click

                //Check to see which item was being clicked and perform appropriate action
                switch (menuItem.getItemId()){

                    //Replacing the main content with ContentFragment Which is our Inbox View;
                        Toast.makeText(getApplicationContext(),"First fragment",Toast.LENGTH_SHORT).show();
                         FirstFragment fragment = new FirstFragment();
               fragmentTransaction = getSupportFragmentManager().beginTransaction();
                        return true;

                    // For rest of the options we just show a toast on click
                        Toast.makeText(getApplicationContext(),"Second fragment",Toast.LENGTH_SHORT).show();
                        SecondFragment fragment2 = new SecondFragment();
               fragmentTransaction2 = getSupportFragmentManager().beginTransaction();
                        return true;

                        Toast.makeText(getApplicationContext(),"Somethings Wrong",Toast.LENGTH_SHORT).show();
                        return true;


        // Initializing Drawer Layout and ActionBarToggle
        drawerLayout = (DrawerLayout) findViewById(;
        ActionBarDrawerToggle actionBarDrawerToggle = new ActionBarDrawerToggle(this,drawerLayout,toolbar,R.string.drawer_open, R.string.drawer_close){

            public void onDrawerClosed(View drawerView) {
                // Code here will be triggered once the drawer closes as we dont want anything to happen so we leave this blank

            public void onDrawerOpened(View drawerView) {
                // Code here will be triggered once the drawer open as we dont want anything to happen so we leave this blank


        //Setting the actionbarToggle to drawer layout

        //calling sync state is necessay or else your hamburger icon wont show up


use this for your toolbar.xml

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

    < xmlns:android=""



use this for navigation header if want to use

<RelativeLayout xmlns:android=""







Calling Member Functions within Main C++

On an informal note, you can also call non-static member functions on temporaries:


(on another informal note, the end of the lifetime of the temporary variable (variable is important, because you can also call non-const member functions) comes at the end of the full expression (";"))

Embed YouTube video - Refused to display in a frame because it set 'X-Frame-Options' to 'SAMEORIGIN'

You only need to copy <iframe> from the YouTube Embed section (click on SHARE below the video and then EMBED and copy the entire iframe).

How to scroll to top of a div using jQuery?

You could just use:

<div id="GridDiv">
// gridview inside...

<a href="#GridDiv">Scroll to top</a>

Can't use SURF, SIFT in OpenCV

As an Anaconda user, I wanted to find one or two appropriate commands to solve the problem. Fortunately, this answer helped. For conda 4.5.11 (use conda -V to check Anaconda version) I have performed next steps:

# Python version does not matter, most likely, check yourself
conda create -n myenv python=3.6     
conda activate myenv
conda install -c menpo opencv

That will install OpenCV 2.4.11. Anaconda's another command conda install -c menpo opencv3 will install OpenCV3, but Python has to be downgraded to 2.7. To install OpenCV3 with Python3 use next (due to the first link):

conda create -n myenv python  
pip install opencv-python==
pip install opencv-contrib-python==

Check the SIFT:

conda activate myenv
>>> cv2.xfeatures2d.SIFT_create()
<xfeatures2d_SIFT 000002A3478655B0>

Change color of Label in C#

I am going to assume this is a WinForms questions (which it feels like, based on it being a "program" rather than a website/app). In which case you can simple do the following to change the text colour of a label:

myLabel.ForeColor = System.Drawing.Color.Red;

Or any other colour of your choice. If you want to be more specific you can use an RGB value like so:

myLabel.ForeColor = Color.FromArgb(0, 0, 0);//(R, G, B) (0, 0, 0 = black)

Having different colours for different users can be done a number of ways. For example, you could allow each user to specify their own RGB value colours, store these somewhere and then load them when the user "connects".

An alternative method could be to just use 2 colours - 1 for the current user (running the app) and another colour for everyone else. This would help the user quickly identify their own messages above others.

A third approach could be to generate the colour randomly - however you will likely get conflicting values that do not show well against your background, so I would suggest not taking this approach. You could have a pre-defined list of "acceptable" colours and just pop one from that list for each user that joins.

preg_match in JavaScript?

This should work:

var matches = text.match(/\[(\d+)\][(\d+)\]/);
var productId = matches[1];
var shopId = matches[2];

Concatenating Matrices in R

Sounds like you're looking for rbind:

> a<-matrix(nrow=10,ncol=5)
> b<-matrix(nrow=20,ncol=5)
> dim(rbind(a,b))
[1] 30  5

Similarly, cbind stacks the matrices horizontally.

I am not entirely sure what you mean by the last question ("Can I do this for matrices of different rows and columns.?")

fatal: Not a valid object name: 'master'

First off, when you create a "bare repository", you're not going to be doing any work with it (it doesn't contain a working copy, so the git branch command is not useful).

Now, the reason you wouldn't have a master branch even after doing a git init is that there are no commits: when you create your first commit, you will then have a master branch.

How to make VS Code to treat other file extensions as certain language?

This works for me.

enter image description here

"files.associations": {"*.bitesize": "yaml"}

How to change Navigation Bar color in iOS 7?

- (void)viewDidLoad
    [super viewDidLoad];

    self.navigationController.navigationBar.barTintColor = [UIColor blueColor];

How do I find the size of a struct?

#include <stdio.h>

typedef struct { char* c; char b; } a;

int main()
    printf("sizeof(a) == %d", sizeof(a));

I get "sizeof(a) == 8", on a 32-bit machine. The total size of the structure will depend on the packing: In my case, the default packing is 4, so 'c' takes 4 bytes, 'b' takes one byte, leaving 3 padding bytes to bring it to the next multiple of 4: 8. If you want to alter this packing, most compilers have a way to alter it, for example, on MSVC:

#pragma pack(1)
typedef struct { char* c; char b; } a;

gives sizeof(a) == 5. If you do this, be careful to reset the packing before any library headers!

Python mock multiple return values

You can assign an iterable to side_effect, and the mock will return the next value in the sequence each time it is called:

>>> from unittest.mock import Mock
>>> m = Mock()
>>> m.side_effect = ['foo', 'bar', 'baz']
>>> m()
>>> m()
>>> m()

Quoting the Mock() documentation:

If side_effect is an iterable then each call to the mock will return the next value from the iterable.

How can I make a list of installed packages in a certain virtualenv?

If you are using pip 19.0.3 and python 3.7.4. Then go for pip list command in your virtualenv. It will show all the installed packages with respective versions.

git push rejected

First, attempt to pull from the same refspec that you are trying to push to.

If this does not work, you can force a git push by using git push -f <repo> <refspec>, but use caution: this method can cause references to be deleted on the remote repository.

Accessing value inside nested dictionaries

You can use the get() on each dict. Make sure that you have added the None check for each access.

Thread Safe C# Singleton Pattern

The Lazy<T> version:

public sealed class Singleton
    private static readonly Lazy<Singleton> lazy
        = new Lazy<Singleton>(() => new Singleton());

    public static Singleton Instance
        => lazy.Value;

    private Singleton() { }

Requires .NET 4 and C# 6.0 (VS2015) or newer.

Convert integer into byte array (Java)

Simple solution which properly handles ByteOrder:


Converting an int into a 4 byte char array (C)

Do you want to address the individual bytes of a 32-bit int? One possible method is a union:

    unsigned int integer;
    unsigned char byte[4];
} foo;

int main()
    foo.integer = 123456789;
    printf("%u %u %u %u\n", foo.byte[3], foo.byte[2], foo.byte[1], foo.byte[0]);

Note: corrected the printf to reflect unsigned values.

Android: show/hide a view using an animation

I created an extension for RelativeLayout that shows/hides Layouts with animations. It can extend any kind of View to gain these features.

import android.content.Context;
import android.util.AttributeSet;
import android.view.View;
import android.view.animation.Animation;
import android.view.animation.AnimationSet;
import android.view.animation.AnimationUtils;
import android.widget.RelativeLayout;

public class AnimatingRelativeLayout extends RelativeLayout
    Context context;
    Animation inAnimation;
    Animation outAnimation;

    public AnimatingRelativeLayout(Context context)
        this.context = context;


    public AnimatingRelativeLayout(Context context, AttributeSet attrs)
        super(context, attrs);
        this.context = context;

    public AnimatingRelativeLayout(Context context, AttributeSet attrs, int defStyle)
        super(context, attrs, defStyle);
        this.context = context;

    private void initAnimations()
        inAnimation = (AnimationSet) AnimationUtils.loadAnimation(context, R.anim.in_animation);
        outAnimation = (Animation) AnimationUtils.loadAnimation(context, R.anim.out_animation);

    public void show()
        if (isVisible()) return;

    public void show(boolean withAnimation)
        if (withAnimation) this.startAnimation(inAnimation);

    public void hide()
        if (!isVisible()) return;

    public void hide(boolean withAnimation)
        if (withAnimation) this.startAnimation(outAnimation);

    public boolean isVisible()
        return (this.getVisibility() == View.VISIBLE);

    public void overrideDefaultInAnimation(Animation inAnimation)
        this.inAnimation = inAnimation;

    public void overrideDefaultOutAnimation(Animation outAnimation)
        this.outAnimation = outAnimation;

You can override the original Animations using overrideDefaultInAnimation and overrideDefaultOutAnimation

My original Animations were fadeIn/Out, I am adding XML animation files for Translating in/out of the screen (Translate to top and from top)


    <?xml version="1.0" encoding="utf-8"?>
<translate xmlns:android=""
    android:toYDelta="0" />


  <?xml version="1.0" encoding="utf-8"?>
<translate xmlns:android=""
    android:toYDelta="-100%p" />

PHP Echo a large block of text

Heredoc syntax can be very useful:

// start the string with 3 <'s and then a word
// it doesn't have to be any particular string or length
// but it's common to make it in all caps.
echo <<< EOT
    in here is your string
    it has the same variable substitution rules
    as a double quoted string.
    when you end it, put the indicator word at the
    start of the line (no spaces before it)
    and put a semicolon after it