Programs & Examples On #Douglas peucker

An algorithm for reducing the number of points in a curve that is approximated by a series of points

C++ catching all exceptions

  1. Can you run your JNI-using Java application from a console window (launch it from a java command line) to see if there is any report of what may have been detected before the JVM was crashed. When running directly as a Java window application, you may be missing messages that would appear if you ran from a console window instead.

  2. Secondly, can you stub your JNI DLL implementation to show that methods in your DLL are being entered from JNI, you are returning properly, etc?

  3. Just in case the problem is with an incorrect use of one of the JNI-interface methods from the C++ code, have you verified that some simple JNI examples compile and work with your setup? I'm thinking in particular of using the JNI-interface methods for converting parameters to native C++ formats and turning function results into Java types. It is useful to stub those to make sure that the data conversions are working and you are not going haywire in the COM-like calls into the JNI interface.

  4. There are other things to check, but it is hard to suggest any without knowing more about what your native Java methods are and what the JNI implementation of them is trying to do. It is not clear that catching an exception from the C++ code level is related to your problem. (You can use the JNI interface to rethrow the exception as a Java one, but it is not clear from what you provide that this is going to help.)

What does servletcontext.getRealPath("/") mean and when should I use it

There is also a change between Java 7 and Java 8. Admittedly it involves the a deprecated call, but I had to add a "/" to get our program working! Here is the link discussing it Why does servletContext.getRealPath returns null on tomcat 8?

How to use a parameter in ExecStart command line?

To attempt command line arguments directly is not possible.

One alternative might be environment variables (

This is where I found the answer:

so sudo systemctl restart myprog -v -- systemctl will think you're trying to set one of its flags, not myprog's flag.

sudo systemctl restart myprog someotheroption -- systemctl will restart myprog and the someotheroption service, if it exists.

How to send a message to a particular client with

SURE: Simply,

This is what you need :"event", data);

whenever a user joined to the server, socket details will be generated including ID. This is the ID really helps to send a message to particular people.

first we need to store all the socket.ids in array,

var people={};

people[name] =;

here name is the receiver name. Example:


So, now we can get that with the receiver name whenever we are sending message:

for this we need to know the receivername. You need to emit receiver name to the server.

final thing is:

 socket.on('chat message', function(data){[data.receiver]).emit('chat message', data.msg);

Hope this works well for you.

Good Luck!!

How to hide element using Twitter Bootstrap and show it using jQuery?

Another way to address this annoyance is to create your own CSS class that does not set the !important at the end of rule, like this:

.hideMe {
    display: none;

and used like so :

<div id="header-mask" class="hideMe"></div>

and now jQuery hiding works


How do I check if a number is positive or negative in C#?

You just have to compare if the value & its absolute value are equal:

if (value == Math.abs(value))
    return "Positif"
else return "Negatif"

How to redirect to another page using PHP

Assuming you're using cookies for login, just call it after your setcookie call -- after all, you must be calling that one before any output too.

Anyway in general you could check for the presence of your form's submit button name at the beginning of the script, do your logic, and then output stuff:

if(isset($_POST['mySubmit'])) {
    // the form was submitted

    // ...
    // perform your logic

    // redirect if login was successful
    header('Location: /somewhere');

// output your stuff here

ios simulator: how to close an app

On the new iPhone X, the simulator was having issues with the mouse/finger gesture.

You can do a long press with the mouse and a close icon will appear. You can use the swipe up gesture as well to close the app.

close app on simulator

How to pass in password to pg_dump?

You can pass a password into pg_dump directly by using the following:

pg_dump "host=localhost port=5432 dbname=mydb user=myuser password=mypass" > mydb_export.sql

How to auto adjust table td width from the content

Remove all widths set using CSS and set white-space to nowrap like so:

.content-loader tr td {
    white-space: nowrap;

I would also remove the fixed width from the container (or add overflow-x: scroll to the container) if you want the fields to display in their entirety without it looking odd...

See more here:

Java: Reading integers from a file into an array

You might have confusions between the different line endings. A Windows file will end each line with a carriage return and a line feed. Some programs on Unix will read that file as if it had an extra blank line between each line, because it will see the carriage return as an end of line, and then see the line feed as another end of line.

SQL Joins Vs SQL Subqueries (Performance)?

The two queries may not be semantically equivalent. If a employee works for more than one department (possible in the enterprise I work for; admittedly, this would imply your table is not fully normalized) then the first query would return duplicate rows whereas the second query would not. To make the queries equivalent in this case, the DISTINCT keyword would have to be added to the SELECT clause, which may have an impact on performance.

Note there is a design rule of thumb that states a table should model an entity/class or a relationship between entities/classes but not both. Therefore, I suggest you create a third table, say OrgChart, to model the relationship between employees and departments.

What is the meaning of git reset --hard origin/master?

In newer version of git (2.23+) you can use:

git switch -C master origin/master

-C is same as --force-create. Related Reference Docs

Simple 'if' or logic statement in Python

If key isn't an int or float but a string, you need to convert it to an int first by doing

key = int(key)

or to a float by doing

key = float(key)

Otherwise, what you have in your question should work, but

if (key < 1) or (key > 34):


if not (1 <= key <= 34):

would be a bit clearer.

Font size relative to the user's screen resolution?

function getFontsByScreenWidth(actuallFontSize, maxScreenWidth){
     return (actualFontSize / maxScreenWidth) * window.innerWidth;

// Example:
fontSize = 18;
maxScreenWidth = 1080;
fontSize = getFontsByScreenWidth(fontSize, maxScreenWidth)


I hope this will help. I am using this formula for my Phase game.

Docker: How to delete all local Docker images

Here is short and quick solution I used

Docker provides a single command that will clean up any resources — images, containers, volumes, and networks — that are dangling (not associated with a container):

docker system prune

To additionally remove any stopped containers and all unused images (not just dangling images), add the -a flag to the command:

docker system prune -a

For more details visit link

Convert NSData to String?

Swift 5:

String(data: data!, encoding: String.Encoding.utf8)

Firebase onMessageReceived not called when app in background

I had the same problem. It is easier to use the 'data message' instead of the 'notification'. The data message always load the class onMessageReceived.

In that class you can make your own notification with the notificationbuilder.


    public void onMessageReceived(RemoteMessage remoteMessage) {

    private void sendNotification(String messageTitle,String messageBody) {
        Intent intent = new Intent(this, MainActivity.class);
        PendingIntent pendingIntent = PendingIntent.getActivity(this,0 /* request code */, intent,PendingIntent.FLAG_UPDATE_CURRENT);

        long[] pattern = {500,500,500,500,500};

        Uri defaultSoundUri= RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION);

        NotificationCompat.Builder notificationBuilder = (NotificationCompat.Builder) new NotificationCompat.Builder(this)

        NotificationManager notificationManager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
        notificationManager.notify(0 /* ID of notification */,;


Yes it stops execution so this is generally preferable to HAVING COUNT(*) > 0 which often won't.

With EXISTS if you look at the execution plan you will see that the actual number of rows coming out of table1 will not be more than 1 irrespective of number of matching records.

In some circumstances SQL Server can convert the tree for the COUNT query to the same as the one for EXISTS during the simplification phase (with a semi join and no aggregate operator in sight) an example of that is discussed in the comments here.

For more complicated sub trees than shown in the question you may occasionally find the COUNT performs better than EXISTS however. Because the semi join needs only retrieve one row from the sub tree this can encourage a plan with nested loops for that part of the tree - which may not work out optimal in practice.

How to squash commits in git after they have been pushed?

Squash commits locally with

git rebase -i origin/master~4 master

and then force push with

git push origin +master

Difference between --force and +

From the documentation of git push:

Note that --force applies to all the refs that are pushed, hence using it with push.default set to matching or with multiple push destinations configured with remote.*.push may overwrite refs other than the current branch (including local refs that are strictly behind their remote counterpart). To force a push to only one branch, use a + in front of the refspec to push (e.g git push origin +master to force a push to the master branch).

How to pass Multiple Parameters from ajax call to MVC Controller

I did that with helping from this question

jquery get querystring from URL

so let see how we will use this function

// Read a page's GET URL variables and return them as an associative array.
function getUrlVars()
    var vars = [], hash;
    var hashes = window.location.href.slice(window.location.href.indexOf('?') + 1).split('&');
    for(var i = 0; i < hashes.length; i++)
        hash = hashes[i].split('=');
        vars[hash[0]] = hash[1];
    return vars;

and now just use it in Ajax call

"ajax": {
    url: '/Departments/GetAllDepartments/',                     
    type: 'GET',                       
    dataType: 'json',                       
    data: getUrlVars()// here is the tricky part

thats all, but if you want know how to use this function or not send all the query string parameters back to actual answer

UL or DIV vertical scrollbar

Sometimes it is not eligible to set height to pixel values. However, it is possible to show vertical scrollbar through setting height of div to 100% and overflow to auto.

Let me show an example:

<div id="content" style="height: 100%; overflow: auto">
  <p>some text</p>

Installing Apple's Network Link Conditioner Tool

For Xcode 8 you gotta download a package named Additional Tools for Xcode 8

For other versions (8.1, 8.2) get the package here

Double click and open the dmg and go to Hardware directory. Double click on Network Link Conditioner.prefPane.

enter image description here

Click on install

enter image description here

Now Network Link Conditioner will be available in System Preferences.

For versions older than Xcode 8, the package to be downloaded is called Hardware IO Tools for Xcode. Get it from this page

Create a temporary table in MySQL with an index from a select

Did find the answer on my own. My problem was, that i use two temporary tables for a join and create the second one out of the first one. But the Index was not copied during creation...

KEY(tmpid), INDEX(tmpid))
SELECT * FROM tblLivecheck_copy WHERE tblLivecheck_copy.devId = did;

SELECT * FROM tmpLivecheck;

... solved my problem.


How to execute a program or call a system command from Python

The subprocess module described above by Eli is very powerful, but the syntax to make a bog-standard system call and inspect its output, is unnecessarily prolix.

The easiest way to make a system call is with the commands module (Linux only).

> import commands
> commands.getstatusoutput("grep matter alice-in-wonderland.txt")
(0, "'Then it doesn't matter which way you go,' said the Cat.")

The first item in the tuple is the return code of the process. The second item is its standard output (and standard error, merged).

The Python devs have 'deprecated' the commands module, but that doesn't mean you shouldn't use it. Only that they're not developing it anymore, which is okay, because it's already perfect (at its small but important function).

Converting a generic list to a CSV string

A general purpose ToCsv() extension method:

  • Supports Int16/32/64, float, double, decimal, and anything supporting ToString()
  • Optional custom join separator
  • Optional custom selector
  • Optional null/empty handling specification (*Opt() overloads)

Usage Examples:

"123".ToCsv() // "1,2,3"
"123".ToCsv(", ") // "1, 2, 3"
new List<int> { 1, 2, 3 }.ToCsv() // "1,2,3"

new List<Tuple<int, string>> 
    Tuple.Create(1, "One"), 
    Tuple.Create(2, "Two") 
.ToCsv(t => t.Item2);  // "One,Two"

((string)null).ToCsv() // throws exception
((string)null).ToCsvOpt() // ""
((string)null).ToCsvOpt(ReturnNullCsv.WhenNull) // null


/// <summary>
/// Specifies when ToCsv() should return null.  Refer to ToCsv() for IEnumerable[T]
/// </summary>
public enum ReturnNullCsv
    /// <summary>
    /// Return String.Empty when the input list is null or empty.
    /// </summary>

    /// <summary>
    /// Return null only if input list is null.  Return String.Empty if list is empty.
    /// </summary>

    /// <summary>
    /// Return null when the input list is null or empty
    /// </summary>

    /// <summary>
    /// Throw if the argument is null
    /// </summary>

/// <summary>
/// Converts IEnumerable list of values to a comma separated string values.
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="values">The values.</param>        
/// <param name="joinSeparator"></param>
/// <returns>System.String.</returns>
public static string ToCsv<T>(
    this IEnumerable<T> values,            
    string joinSeparator = ",")
    return ToCsvOpt<T>(values, null /*selector*/, ReturnNullCsv.ThrowIfNull, joinSeparator);

/// <summary>
/// Converts IEnumerable list of values to a comma separated string values.
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="values">The values.</param>
/// <param name="selector">An optional selector</param>
/// <param name="joinSeparator"></param>
/// <returns>System.String.</returns>
public static string ToCsv<T>(
    this IEnumerable<T> values,
    Func<T, string> selector,            
    string joinSeparator = ",") 
    return ToCsvOpt<T>(values, selector, ReturnNullCsv.ThrowIfNull, joinSeparator);

/// <summary>
/// Converts IEnumerable list of values to a comma separated string values.
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="values">The values.</param>
/// <param name="returnNullCsv">Return mode (refer to enum ReturnNullCsv).</param>
/// <param name="joinSeparator"></param>
/// <returns>System.String.</returns>
public static string ToCsvOpt<T>(
    this IEnumerable<T> values,
    ReturnNullCsv returnNullCsv = ReturnNullCsv.Never,
    string joinSeparator = ",")
    return ToCsvOpt<T>(values, null /*selector*/, returnNullCsv, joinSeparator);

/// <summary>
/// Converts IEnumerable list of values to a comma separated string values.
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="values">The values.</param>
/// <param name="selector">An optional selector</param>
/// <param name="returnNullCsv">Return mode (refer to enum ReturnNullCsv).</param>
/// <param name="joinSeparator"></param>
/// <returns>System.String.</returns>
public static string ToCsvOpt<T>(
    this IEnumerable<T> values, 
    Func<T, string> selector,
    ReturnNullCsv returnNullCsv = ReturnNullCsv.Never,
    string joinSeparator = ",")
    switch (returnNullCsv)
        case ReturnNullCsv.Never:
            if (!values.AnyOpt())
                return string.Empty;

        case ReturnNullCsv.WhenNull:
            if (values == null)
                return null;

        case ReturnNullCsv.WhenNullOrEmpty:
            if (!values.AnyOpt())
                return null;

        case ReturnNullCsv.ThrowIfNull:
            if (values == null)
                throw new ArgumentOutOfRangeException("ToCsvOpt was passed a null value with ReturnNullCsv = ThrowIfNull.");

            throw new ArgumentOutOfRangeException("returnNullCsv", returnNullCsv, "Out of range.");

    if (selector == null)
        if (typeof(T) == typeof(Int16) || 
            typeof(T) == typeof(Int32) || 
            typeof(T) == typeof(Int64))
            selector = (v) => Convert.ToInt64(v).ToStringInvariant();
        else if (typeof(T) == typeof(decimal))
            selector = (v) => Convert.ToDecimal(v).ToStringInvariant();
        else if (typeof(T) == typeof(float) ||
                typeof(T) == typeof(double))
            selector = (v) => Convert.ToDouble(v).ToString(CultureInfo.InvariantCulture);
            selector = (v) => v.ToString();

    return String.Join(joinSeparator, values.Select(v => selector(v)));

public static string ToStringInvariantOpt(this Decimal? d)
    return d.HasValue ? d.Value.ToStringInvariant() : null;

public static string ToStringInvariant(this Decimal d)
    return d.ToString(CultureInfo.InvariantCulture);

public static string ToStringInvariantOpt(this Int64? l)
    return l.HasValue ? l.Value.ToStringInvariant() : null;

public static string ToStringInvariant(this Int64 l)
    return l.ToString(CultureInfo.InvariantCulture);

public static string ToStringInvariantOpt(this Int32? i)
    return i.HasValue ? i.Value.ToStringInvariant() : null;

public static string ToStringInvariant(this Int32 i)
    return i.ToString(CultureInfo.InvariantCulture);

public static string ToStringInvariantOpt(this Int16? i)
    return i.HasValue ? i.Value.ToStringInvariant() : null;

public static string ToStringInvariant(this Int16 i)
    return i.ToString(CultureInfo.InvariantCulture);

How to easily consume a web service from PHP

I've had great success with wsdl2php. It will automatically create wrapper classes for all objects and methods used in your web service.

How to do a for loop in windows command line?

The commandline interpreter does indeed have a FOR construct that you can use from the command prompt or from within a batch file.

For your purpose, you probably want something like:

FOR %i IN (*.ext) DO my-function %i

Which will result in the name of each file with extension *.ext in the current directory being passed to my-function (which could, for example, be another .bat file).

The (*.ext) part is the "filespec", and is pretty flexible with how you specify sets of files. For example, you could do:

FOR %i IN (C:\Some\Other\Dir\*.ext) DO my-function %i

To perform an operation in a different directory.

There are scores of options for the filespec and FOR in general. See


from the command prompt for more information.

close vs shutdown socket?

I've also had success under linux using shutdown() from one pthread to force another pthread currently blocked in connect() to abort early.

Under other OSes (OSX at least), I found calling close() was enough to get connect() fail.

How to append binary data to a buffer in node.js

insert byte to specific place.

insertToArray(arr,index,item) {
   return Buffer.concat([arr.slice(0,index),Buffer.from(item,"utf-8"),arr.slice(index)]);

Skip first entry in for loop in python?

The other answers only work for a sequence.

For any iterable, to skip the first item:

itercars = iter(cars)
for car in itercars:
    # do work

If you want to skip the last, you could do:

itercars = iter(cars)
# add 'next(itercars)' here if you also want to skip the first
prev = next(itercars)
for car in itercars:
    # do work on 'prev' not 'car'
    # at end of loop:
    prev = car
# now you can do whatever you want to do to the last one on 'prev'

How to split a string and assign it to variables

What you are doing is, you are accepting split response in two different variables, and strings.Split() is returning only one response and that is an array of string. you need to store it to single variable and then you can extract the part of string by fetching the index value of an array.

example :

 var hostAndPort string
    hostAndPort = ""
    sArray := strings.Split(hostAndPort, ":")
    fmt.Println("host : " + sArray[0])
    fmt.Println("port : " + sArray[1])

matplotlib has no attribute 'pyplot'

Did you import it? Importing matplotlib is not enough.

>>> import matplotlib
>>> matplotlib.pyplot
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: 'module' object has no attribute 'pyplot'


>>> import matplotlib.pyplot
>>> matplotlib.pyplot


pyplot is a submodule of matplotlib and not immediately imported when you import matplotlib.

The most common form of importing pyplot is

import matplotlib.pyplot as plt

Thus, your statements won't be too long, e.g.


instead of


And: pyplot is not a function, it's a module! So don't call it, use the functions defined inside this module instead. See my example above

Getting only Month and Year from SQL DATE

Get Month & Year From Date

DECLARE @lcMonth nvarchar(10)
DECLARE @lcYear nvarchar(10)


Detailed 500 error message, ASP + IIS 7.5

Fot people who have tried EVERYTHING and just CANNOT get the error details to show, like me, it's a good idea to check the different levels of configuration. I have a config file on Website level and on Application level (inside the website) check both. Also, as it turned out, I had Detailed Errors disabled on the highest node in IIS (just underneath Start Page, it has the name that is the same as the webservers computername). Check the Error Pages there.

How do I decode a string with escaped unicode?

Note that the use of unescape() is deprecated and doesn't work with the TypeScript compiler, for example.

Based on radicand's answer and the comments section below, here's an updated solution:

var string = "http\\u00253A\\u00252F\\";
decodeURIComponent(JSON.parse('"' + string.replace(/\"/g, '\\"') + '"'));

Python - Count elements in list


>>> someList=[]
>>> print len(someList)

Android camera android.hardware.Camera deprecated

Answers provided here as which camera api to use are wrong. Or better to say they are insufficient.

Some phones (for example Samsung Galaxy S6) could be above api level 21 but still may not support Camera2 api.

CameraCharacteristics mCameraCharacteristics = mCameraManager.getCameraCharacteristics(mCameraId);
Integer level = mCameraCharacteristics.get(CameraCharacteristics.INFO_SUPPORTED_HARDWARE_LEVEL);
if (level == null || level == CameraCharacteristics.INFO_SUPPORTED_HARDWARE_LEVEL_LEGACY) {
    return false;

CameraManager class in Camera2Api has a method to read camera characteristics. You should check if hardware wise device is supporting Camera2 Api or not.

But there are more issues to handle if you really want to make it work for a serious application: Like, auto-flash option may not work for some devices or battery level of the phone might create a RuntimeException on Camera or phone could return an invalid camera id and etc.

So best approach is to have a fallback mechanism as for some reason Camera2 fails to start you can try Camera1 and if this fails as well you can make a call to Android to open default Camera for you.

How do I completely uninstall Node.js, and reinstall from beginning (Mac OS X)

This fixed it for me Fixing npm On Mac OS X for Homebrew Users. And it does not require too many steps.

Just go to the solution part if you don't care about the why.

Here is the relevant part for convenience:


This solution fixes the error caused by trying to run npm update npm -g. Once you're finished, you also won't need to use sudo to install npm modules globally.

Before you start, make a note of any globally installed npm packages. These instructions will have you remove all of those packages. After you're finished you'll need to re-install them.

Run the following commands to remove all existing global npm modules, uninstall node & npm, re-install node with the correct defaults, configure the location for global npm modules to be installed, and then install npm as its own pacakge.

rm -rf /usr/local/lib/node_modules
brew uninstall node
brew install node --without-npm
echo prefix=~/.npm-packages >> ~/.npmrc
curl -L | sh

Node and npm should be correctly installed at this point. The final step is to add ~/.npm-packages/bin to your PATH so npm and global npm packages are usable. To do this, add the following line to your ~/.bash_profile:

export PATH="$HOME/.npm-packages/bin:$PATH"

Now you can re-install any global npm packages you need without any problems.

Scanner is never closed

Here is some better usage of java for scanner

try(Scanner sc = new Scanner( {

    //Use sc as you need

} catch (Exception e) {

        //  handle exception


Configure WAMP server to send email

You need a SMTP server to send your mail. If you have one available which does not require SMTP authentification (maybe your ISP's?) just edit the 'SMTP' ([mail function]) setting in your php.ini file.

If this is no option because your SMTP server requires authentification you won't be able to use the internal mail() function and have to use some 3rd party class which supports smtp auth. e.g.

Creating a simple configuration file and parser in C++

Why not trying something simple and human-readable, like JSON (or XML) ?

There are many pre-made open-source implementations of JSON (or XML) for C++ - I would use one of them.

And if you want something more "binary" - try BJSON or BSON :)

Where do I find the current C or C++ standard documents?

PDF versions of the standard

As of 1st September 2014, the best locations by price for C and C++ standards documents in PDF are:

You cannot usually get old revisions of a standard (any standard) directly from the standards bodies shortly after a new edition of the standard is released. Thus, standards for C89, C90, C99, C++98, C++03 will be hard to find for purchase from a standards body. If you need an old revision of a standard, check Techstreet as one possible source. For example, it can still provide the Canadian version CAN/CSA-ISO/IEC 9899:1990 standard in PDF, for a fee.

Non-PDF electronic versions of the standard

Print versions of the standard

Print copies of the standards are available from national standards bodies and ISO but are very expensive.

If you want a hardcopy of the C90 standard for much less money than above, you may be able to find a cheap used copy of Herb Schildt's book The Annotated ANSI Standard at Amazon, which contains the actual text of the standard (useful) and commentary on the standard (less useful - it contains several dangerous and misleading errors).

The C99 and C++03 standards are available in book form from Wiley and the BSI (British Standards Institute):

Standards committee draft versions (free)

The working drafts for future standards are often available from the committee websites:

If you want to get drafts from the current or earlier C/C++ standards, there are some available for free on the internet:

For C:

(Almost the same as ANSI X3.159-198 (C89) except for the frontmatter and section numbering. Note that the conversion between ANSI and ISO/IEC Standard is seen inside this document, the document refers to its name as "ANSI/ISO: 9899/99" although this isn't the right name of the later made standard of it, the right name is "ISO/IEC 9899:1990")

For C++:

Note that these documents are not the same as the standard, though the versions just prior to the meetings that decide on a standard are usually very close to what is in the final standard. The FCD (Final Committee Draft) versions are password protected; you need to be on the standards committee to get them.

Even though the draft versions might be very close to the final ratified versions of the standards, some of this post's editors would strongly advise you to get a copy of the actual documents — especially if you're planning on quoting them as references. Of course, starving students should go ahead and use the drafts if strapped for cash.

It appears that, if you are willing and able to wait a few months after ratification of a standard, to search for "INCITS/ISO/IEC" instead of "ISO/IEC" when looking for a standard is the key. By doing so, one of this post's editors was able to find the C11 and C++11 standards at reasonable prices. For example, if you search for "INCITS/ISO/IEC 9899:2011" instead of "ISO/IEC 9899:2011" on you will find the reasonably priced PDF version.

The site provides short-URL links to the C++ current working draft and draft standards, and committee papers:

The current draft of the standard is maintained as LaTeX sources on Github. These sources can be converted to HTML using cxxdraft-htmlgen. The following sites maintain HTML pages so generated:

Tim Song also maintains generated HTML and PDF versions of the Networking TS and Ranges TS.

Set custom HTML5 required field validation message

You can do this setting up an event listener for the 'invalid' across all the inputs of the same type, or just one, depending on what you need, and then setting up the proper message.

[] document.querySelectorAll('[type="email"]'), function(emailElement) {
    emailElement.addEventListener('invalid', function() {
        var message = this.value + 'is not a valid email address';
    }, false);

    emailElement.addEventListener('input', function() {
    }, false);

The second piece of the script, the validity message will be reset, since otherwise won't be possible to submit the form: for example this prevent the message to be triggered even when the email address has been corrected.

Also you don't have to set up the input field as required, since the 'invalid' will be triggered once you start typing in the input.

Here is a fiddle for that: Hope that helps!

get all the images from a folder in php

when you want to get all image from folder then use glob() built in function which help to get all image . But when you get all then sometime need to check that all is valid so in this case this code help you. this code will also check that it is image

  $all_files = glob("mytheme/images/myimages/*.*");
  for ($i=0; $i<count($all_files); $i++)
      $image_name = $all_files[$i];
      $supported_format = array('gif','jpg','jpeg','png');
      $ext = strtolower(pathinfo($image_name, PATHINFO_EXTENSION));
      if (in_array($ext, $supported_format))
            echo '<img src="'.$image_name .'" alt="'.$image_name.'" />'."<br /><br />";
          } else {

for more information

PHP Manual

get Context in non-Activity class

If your class is non-activity class, and creating an instance of it from the activiy, you can pass an instance of context via constructor of the later as follows:

class YourNonActivityClass{

// variable to hold context
private Context context;

//save the context recievied via constructor in a local variable

public YourNonActivityClass(Context context){


You can create instance of this class from the activity as follows:

new YourNonActivityClass(this);

Changing java platform on which netbeans runs

Fix this by moving my jdk folder to other disk

Configuring ObjectMapper in Spring

Above Spring 4, there is no need to configure MappingJacksonHttpMessageConverter if you only intend to configure ObjectMapper.

(configure MappingJacksonHttpMessageConverter will cause you to lose other MessageConverter)

You just need to do:

public class MyObjectMapper extends ObjectMapper {

    private static final long serialVersionUID = 4219938065516862637L;

    public MyObjectMapper() {

And in your Spring configuration, create this bean:

public MyObjectMapper myObjectMapper() {        
    return new MyObjectMapper();

Input size vs width

I want to say this goes against the "conventional wisdom", but I generally prefer to use size. The reason for this is precisely the reason that many people say not to: the width of the field will vary from browser to browser, depending on font size. Specifically, it will always be large enough to display the specified number of characters, regardless of browser settings.

For example, if I have a date field, I typically want the field wide enough to display either 8 or 10 characters (two digit month and day and either two or four digit year, with separators). Setting the size attribute essentially guarantees me that the entire date will be visible, with minimal wasted space. Similarly for most numbers - I know the range of values expected, so I'll set the size attribute to the proper number of digits, plus decimal point if applicable.

As far as I can tell, no CSS attribute does this. Setting a width in em, for example, is based off the height, not the width, and thus is not very precise if you want to display a known number of characters.

Of course, this logic doesn't always apply - a name entry field, for example, could contain any number of characters. In those cases I'll fall back to CSS width properties, typically in px. However, I would say the majority of fields I make have some sort of known content, and by specifying the size attribute I can make sure that most of the content, in most cases, is displayed without clipping.

Can I catch multiple Java exceptions in the same catch clause?

Within Java 7 you can define multiple catch clauses like:

catch (IllegalArgumentException | SecurityException e)

How to use a WSDL

I would fire up Visual Studio, create a web project (or console app - doesn't matter).

For .Net Standard:

  1. I would right-click on the project and pick "Add Service Reference" from the Add context menu.
  2. I would click on Advanced, then click on Add Service Reference.
  3. I would get the complete file path of the wsdl and paste into the address bar. Then fire the Arrow (go button).
  4. If there is an error trying to load the file, then there must be a broken and unresolved url the file needs to resolve as shown below: enter image description here Refer to this answer for information on how to fix: Stackoverflow answer to: Unable to create service reference for wsdl file

If there is no error, you should simply set the NameSpace you want to use to access the service and it'll be generated for you.

For .Net Core

  1. I would right click on the project and pick Connected Service from the Add context menu.
  2. I would select Microsoft WCF Web Service Reference Provider from the list.
  3. I would press browse and select the wsdl file straight away, Set the namespace and I am good to go. Refer to the error fix url above if you encounter any error.

Any of the methods above will generate a simple, very basic WCF client for you to use. You should find a "YourservicenameClient" class in the generated code.

For reference purpose, the generated cs file can be found in your Obj/debug(or release)/XsdGeneratedCode and you can still find the dlls in the TempPE folder.

The created Service(s) should have methods for each of the defined methods on the WSDL contract.

Instantiate the client and call the methods you want to call - that's all there is!

YourServiceClient client = new YourServiceClient();

If you need to specify the remote URL (not using the one created by default), you can easily do this in the constructor of the proxy client:

YourServiceClient client = new YourServiceClient("configName", "remoteURL");

where configName is the name of the endpoint to use (you will use all the settings except the URL), and the remoteURL is a string representing the URL to connect to (instead of the one contained in the config).

Most common C# bitwise operations on enums

The idiom is to use the bitwise or-equal operator to set bits:

flags |= 0x04;

To clear a bit, the idiom is to use bitwise and with negation:

flags &= ~0x04;

Sometimes you have an offset that identifies your bit, and then the idiom is to use these combined with left-shift:

flags |= 1 << offset;
flags &= ~(1 << offset);

hash function for string

I have tried these hash functions and got the following result. I have about 960^3 entries, each 64 bytes long, 64 chars in different order, hash value 32bit. Codes from here.

Hash function    | collision rate | how many minutes to finish
MurmurHash3      |           6.?% |                      4m15s
Jenkins One..    |           6.1% |                      6m54s   
Bob, 1st in link |          6.16% |                      5m34s
SuperFastHash    |            10% |                      4m58s
bernstein        |            20% |       14s only finish 1/20
one_at_a_time    |          6.16% |                       7m5s
crc              |          6.16% |                      7m56s

One strange things is that almost all the hash functions have 6% collision rate for my data.

How to call a function within class?

That doesn't work because distToPoint is inside your class, so you need to prefix it with the classname if you want to refer to it, like this: classname.distToPoint(self, p). You shouldn't do it like that, though. A better way to do it is to refer to the method directly through the class instance (which is the first argument of a class method), like so: self.distToPoint(p).

Insert default value when parameter is null

Try an if statement ...

if @value is null 
    insert into t (value) values (default)
    insert into t (value) values (@value)

Granting DBA privileges to user in Oracle

You need only to write:


Because this already makes the user a DB Administrator

How to unmount a busy device

Avoid umount -l

At the time of writing, the top-voted answer recommends using umount -l.

umount -l is dangerous or at best unsafe. In summary:

  • It doesn't actually unmount the device, it just removes the filesystem from the namespace. Writes to open files can continue.
  • It can cause btrfs filesystem corruption

Work around / alternative

The useful behaviour of umount -l is hiding the filesystem from access by absolute pathnames, thereby minimising further moutpoint usage.

This same behaviour can be achieved by mounting an empty directory with permissions 000 over the directory to be unmounted.

Then any new accesses to filenames in the below the mountpoint will hit the newly overlaid directory with zero permissions - new blockers to the unmount are thereby prevented.

First try to remount,ro

The major unmount achievement to be unlocked is the read-only remount. When you gain the remount,ro badge, you know that:

  1. All pending data has been written to disk
  2. All future write attempts will fail
  3. The data is in a consistent state, should you need to physcially disconnect the device.

mount -o remount,ro /dev/device is guaranteed to fail if there are files open for writing, so try that straight up. You may be feeling lucky, punk!

If you are unlucky, focus only on processes with files open for writing:

lsof +f -- /dev/<devicename> | awk 'NR==1 || $4~/[0-9]+[uw -]/'

You should then be able to remount the device read-only and ensure a consistent state.

If you can't remount read-only at this point, investigate some of the other possible causes listed here.

Read-only re-mount achievement unlocked ?

Congratulations, your data on the mountpoint is now consistent and protected from future writing.

Why fuser is inferior to lsof

Why not use use fuser earlier? Well, you could have, but fuser operates upon a directory, not a device, so if you wanted to remove the mountpoint from the file name space and still use fuser, you'd need to:

  1. Temporarily duplicate the mountpoint with mount -o bind /media/hdd /mnt to another location
  2. Hide the original mount point and block the namespace:

Here's how:

null_dir=$(sudo mktemp --directory --tmpdir empty.XXXXX")
sudo chmod 000 "$null_dir"

# A request to remount,ro will fail on a `-o bind,ro` duplicate if there are
# still files open for writing on the original as each mounted instance is
# checked.
# So, avoid remount, and bind mount instead:
sudo mount -o bind,ro "$original" "$original_duplicate"

# Don't propagate/mirror the empty directory just about hide the original
sudo mount --make-private "$original_duplicate"

# Hide the original mountpoint
sudo mount -o bind,ro "$null_dir" "$original"

You'd then have:

  1. The original namespace hidden (no more files could be opened, the problem can't get worse)
  2. A duplicate bind mounted directory (as opposed to a device) on which to run fuser.

This is more convoluted[1], but allows you to use:

fuser -vmMkiw <mountpoint>

which will interactively ask to kill the processes with files open for writing. Of course, you could do this without hiding the mount point at all, but the above mimicks umount -l, without any of the dangers.

The -w switch restricts to writing processes, and the -i is interactive, so after a read-only remount, if you're it a hurry you could then use:

fuser -vmMk <mountpoint>

to kill all remaining processes with files open under the mountpoint.

Hopefully at this point, you can unmount the device. (You'll need to run umount on the mountpoint twice if you've bind mounted a mode 000 directory on top.)

Or use:

fuser -vmMki <mountpoint>

to interactively kill the remaining read-only processes blocking the unmount.

Dammit, I still get target is busy!

Open files aren't the only unmount blocker. See here and here for other causes and their remedies.

Even if you've got some lurking gremlin which is preventing you from fully unmounting the device, you have at least got your filesystem in a consistent state.

You can then use lsof +f -- /dev/device to list all processes with open files on the device containing the filesystem, and then kill them.

[1] It is less convoluted to use mount --move, but that requires mount --make-private /parent-mount-point which has implications. Basically, if the mountpoint is mounted under the / filesystem, you'd want to avoid this.

The operation cannot be completed because the DbContext has been disposed error

Change this:

using (var dataContext = new dataContext())
    users = dataContext.Users.Where(x => x.AccountID == accountId && x.IsAdmin == false);

        ret = users.Select(x => x.ToInfo()).ToList(); 


to this:

using (var dataContext = new dataContext())
    return = dataContext.Users.Where(x => x.AccountID == accountId && x.IsAdmin == false).Select(x => x.ToInfo()).ToList();

The gist is that you only want to force the enumeration of the context dataset once. Let the caller deal with empty set scenario, as they should.

How to filter a data frame

You are missing a comma in your statement.

Try this:

data[data[, "Var1"]>10, ]


data[data$Var1>10, ]


subset(data, Var1>10)

As an example, try it on the built-in dataset, mtcars


mtcars[mtcars[, "mpg"]>25, ]

                mpg cyl  disp  hp drat    wt  qsec vs am gear carb
Fiat 128       32.4   4  78.7  66 4.08 2.200 19.47  1  1    4    1
Honda Civic    30.4   4  75.7  52 4.93 1.615 18.52  1  1    4    2
Toyota Corolla 33.9   4  71.1  65 4.22 1.835 19.90  1  1    4    1
Fiat X1-9      27.3   4  79.0  66 4.08 1.935 18.90  1  1    4    1
Porsche 914-2  26.0   4 120.3  91 4.43 2.140 16.70  0  1    5    2
Lotus Europa   30.4   4  95.1 113 3.77 1.513 16.90  1  1    5    2

mtcars[mtcars$mpg>25, ]

                mpg cyl  disp  hp drat    wt  qsec vs am gear carb
Fiat 128       32.4   4  78.7  66 4.08 2.200 19.47  1  1    4    1
Honda Civic    30.4   4  75.7  52 4.93 1.615 18.52  1  1    4    2
Toyota Corolla 33.9   4  71.1  65 4.22 1.835 19.90  1  1    4    1
Fiat X1-9      27.3   4  79.0  66 4.08 1.935 18.90  1  1    4    1
Porsche 914-2  26.0   4 120.3  91 4.43 2.140 16.70  0  1    5    2
Lotus Europa   30.4   4  95.1 113 3.77 1.513 16.90  1  1    5    2

subset(mtcars, mpg>25)

                mpg cyl  disp  hp drat    wt  qsec vs am gear carb
Fiat 128       32.4   4  78.7  66 4.08 2.200 19.47  1  1    4    1
Honda Civic    30.4   4  75.7  52 4.93 1.615 18.52  1  1    4    2
Toyota Corolla 33.9   4  71.1  65 4.22 1.835 19.90  1  1    4    1
Fiat X1-9      27.3   4  79.0  66 4.08 1.935 18.90  1  1    4    1
Porsche 914-2  26.0   4 120.3  91 4.43 2.140 16.70  0  1    5    2
Lotus Europa   30.4   4  95.1 113 3.77 1.513 16.90  1  1    5    2

Regular expression to search multiple strings (Textpad)

If I understand what you are asking, it is a regular expression like this:


This matches the three sets of digit strings at beginning of line only.

How to force a line break in a long word in a DIV?

Do this:

<div id="sampleDiv">aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa</div>

   overflow-wrap: break-word;

Is there any way to kill a Thread?

You should never forcibly kill a thread without cooperating with it.

Killing a thread removes any guarantees that try/finally blocks set up so you might leave locks locked, files open, etc.

The only time you can argue that forcibly killing threads is a good idea is to kill a program fast, but never single threads.

Dynamically create an array of strings with malloc

#define ID_LEN 5
char **orderedIds;
int i;
int variableNumberOfElements = 5; /* Hard coded here */

orderedIds = (char **)malloc(variableNumberOfElements * (ID_LEN + 1) * sizeof(char));


JQuery Datatables : Cannot read property 'aDataSort' of undefined

For me, the bug was in DataTables itself; The code for sorting in DataTables 1.10.9 will not check for bounds; thus if you use something like

order: [[1, 'asc']]

with an empty table, there is no row idx 1 -> this exception ensures. This happened as the data for the table was being fetched asynchronously. Initially, on page loading the dataTable gets initialized without data. It should be updated later as soon as the result data is fetched.

My solution:

// add within function _fnStringToCss( s ) in datatables.js
// directly after this line
// srcCol = nestedSort[i][0];

if(srcCol >= aoColumns.length) {

// this line follows:
// aDataSort = aoColumns[ srcCol ].aDataSort;

GCC fatal error: stdio.h: No such file or directory

ubuntu users:

sudo apt-get install libc6-dev

specially ruby developers that have problem installing gem install json -v '1.8.2' on their VMs

How do I modify the URL without reloading the page?

Any changes of the loction (either window.location or document.location) will cause a request on that new URL, if you’re not just changing the URL fragment. If you change the URL, you change the URL.

Use server-side URL rewrite techniques like Apache’s mod_rewrite if you don’t like the URLs you are currently using.

How do I center list items inside a UL element?

    margin:0px auto 0px auto;

This should work.

What is PAGEIOLATCH_SH wait type in SQL Server?

From Microsoft documentation:


Occurs when a task is waiting on a latch for a buffer that is in an I/O request. The latch request is in Shared mode. Long waits may indicate problems with the disk subsystem.

In practice, this almost always happens due to large scans over big tables. It almost never happens in queries that use indexes efficiently.

If your query is like this:

Select * from <table> where <col1> = <value> order by <PrimaryKey>

, check that you have a composite index on (col1, col_primary_key).

If you don't have one, then you'll need either a full INDEX SCAN if the PRIMARY KEY is chosen, or a SORT if an index on col1 is chosen.

Both of them are very disk I/O consuming operations on large tables.

How to resolve git error: "Updates were rejected because the tip of your current branch is behind"

You are not currently on a branch. To push the history leading to the current (detached HEAD) state now, use

git push origin HEAD:<name-of-remote-branch>

CSS to select/style first word

I have to disagree with Dale... The strong element is actually the wrong element to use, implying something about the meaning, use, or emphasis of the content while you are simply intending to provide style to the element.

Ideally you would be able to accomplish this with a pseudo-class and your stylesheet, but as that is not possible you should make your markup semantically correct and use <span class="first-word">.

How do I add a project as a dependency of another project?

Assuming the MyEjbProject is not another Maven Project you own or want to build with maven, you could use system dependencies to link to the existing jar file of the project like so


That said it is usually the better (and preferred way) to install the package to the repository either by making it a maven project and building it or installing it the way you already seem to do.

If they are, however, dependent on each other, you can always create a separate parent project (has to be a "pom" project) declaring the two other projects as its "modules". (The child projects would not have to declare the third project as their parent). As a consequence you'd get a new directory for the new parent project, where you'd also quite probably put the two independent projects like this:

|- pom.xml
|- MyEJBProject
|   `- pom.xml
`- MyWarProject
    `- pom.xml

The parent project would get a "modules" section to name all the child modules. The aggregator would then use the dependencies in the child modules to actually find out the order in which the projects are to be built)



That way the projects can relate to each other but (once they are installed in the local repository) still be used independently as artifacts in other projects

Finally, if your projects are not in related directories, you might try to give them as relative modules:

 |- mywarproject
 |   `pom.xml
 |- myejbproject
 |   `pom.xml
 `- parent

now you could just do this (worked in maven 2, just tried it):


How do I send a file in Android from a mobile device to server using http?

the most effective method is to use org.apache.http.entity.mime.MultipartEntity;

see this code from the link using org.apache.http.entity.mime.MultipartEntity;

public class SimplePostRequestTest3 {

   * @param args
  public static void main(String[] args) {
    HttpClient httpclient = new DefaultHttpClient();
    HttpPost httppost = new HttpPost("http://localhost:8080/HTTP_TEST_APP/index.jsp");

    try {
      FileBody bin = new FileBody(new File("C:/ABC.txt"));
      StringBody comment = new StringBody("BETHECODER HttpClient Tutorials");

      MultipartEntity reqEntity = new MultipartEntity();
      reqEntity.addPart("fileup0", bin);
      reqEntity.addPart("fileup1", comment);

      reqEntity.addPart("ONE", new StringBody("11111111"));
      reqEntity.addPart("TWO", new StringBody("222222222"));

      System.out.println("Requesting : " + httppost.getRequestLine());
      ResponseHandler<String> responseHandler = new BasicResponseHandler();
      String responseBody = httpclient.execute(httppost, responseHandler);

      System.out.println("responseBody : " + responseBody);

    } catch (UnsupportedEncodingException e) {
    } catch (ClientProtocolException e) {
    } catch (IOException e) {
    } finally {



Example Link

Saving a Numpy array as an image

If you have matplotlib, you can do:

import matplotlib.pyplot as plt
plt.imshow(matrix) #Needs to be in row,col order

This will save the plot (not the images itself). enter image description here

Static linking vs dynamic linking

Static linking is a process in compile time when a linked content is copied into the primary binary and becomes a single binary.


  • compile time is longer
  • output binary is bigger

Dynamic linking is a process in runtime when a linked content is loaded. This technic allows to:

  • upgrade linked binary without recompiling a primary one that increase an ABI stability[About]
  • has a single shared copy


  • start time is slower(linked content should be copied)
  • linker errors are thrown in runtime

[iOS Static vs Dynamic framework]

Cannot start GlassFish 4.1 from within Netbeans 8.0.1 Service area

I get the same error when I run Oracle XE instance on the same machine. As my database is Oracle, I preferred changing Glassfish's default port:

  1. Locate domain.xml inside Glassfish installation folders.
  2. Change the the port on the below line:

  <network-listener port="9090" protocol="http-listener-1" transport="tcp" name="http-listener-1" thread-pool="http-thread-pool"></network-listener>_x000D_

Split an integer into digits to compute an ISBN checksum

After own diligent searches I found several solutions, where each has advantages and disadvantages. Use the most suitable for your task.

All examples tested with the CPython 3.5 on the operation system GNU/Linux Debian 8.

Using a recursion


def get_digits_from_left_to_right(number, lst=None):
    """Return digits of an integer excluding the sign."""

    if lst is None:
        lst = list()

    number = abs(number)

    if number < 10:
        return tuple(lst)

    get_digits_from_left_to_right(number // 10, lst)
    lst.append(number % 10)

    return tuple(lst)


In [121]: get_digits_from_left_to_right(-64517643246567536423)
Out[121]: (6, 4, 5, 1, 7, 6, 4, 3, 2, 4, 6, 5, 6, 7, 5, 3, 6, 4, 2, 3)

In [122]: get_digits_from_left_to_right(0)
Out[122]: (0,)

In [123]: get_digits_from_left_to_right(123012312312321312312312)
Out[123]: (1, 2, 3, 0, 1, 2, 3, 1, 2, 3, 1, 2, 3, 2, 1, 3, 1, 2, 3, 1, 2, 3, 1, 2)

Using the function divmod


def get_digits_from_right_to_left(number):
    """Return digits of an integer excluding the sign."""

    number = abs(number)

    if number < 10:
        return (number, )

    lst = list()

    while number:
        number, digit = divmod(number, 10)
        lst.insert(0, digit)

    return tuple(lst)


In [125]: get_digits_from_right_to_left(-3245214012321021213)
Out[125]: (3, 2, 4, 5, 2, 1, 4, 0, 1, 2, 3, 2, 1, 0, 2, 1, 2, 1, 3)

In [126]: get_digits_from_right_to_left(0)
Out[126]: (0,)

In [127]: get_digits_from_right_to_left(9999999999999999)
Out[127]: (9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9)

Using a construction tuple(map(int, str(abs(number)))

In [109]: tuple(map(int, str(abs(-123123123))))
Out[109]: (1, 2, 3, 1, 2, 3, 1, 2, 3)

In [110]: tuple(map(int, str(abs(1412421321312))))
Out[110]: (1, 4, 1, 2, 4, 2, 1, 3, 2, 1, 3, 1, 2)

In [111]: tuple(map(int, str(abs(0))))
Out[111]: (0,)

Using the function re.findall

In [112]: tuple(map(int, re.findall(r'\d', str(1321321312))))
Out[112]: (1, 3, 2, 1, 3, 2, 1, 3, 1, 2)

In [113]: tuple(map(int, re.findall(r'\d', str(-1321321312))))
Out[113]: (1, 3, 2, 1, 3, 2, 1, 3, 1, 2)

In [114]: tuple(map(int, re.findall(r'\d', str(0))))
Out[114]: (0,)

Using the module decimal

In [117]: decimal.Decimal(0).as_tuple().digits
Out[117]: (0,)

In [118]: decimal.Decimal(3441120391321).as_tuple().digits
Out[118]: (3, 4, 4, 1, 1, 2, 0, 3, 9, 1, 3, 2, 1)

In [119]: decimal.Decimal(-3441120391321).as_tuple().digits
Out[119]: (3, 4, 4, 1, 1, 2, 0, 3, 9, 1, 3, 2, 1)

Programmatically change input type of the EditText from PASSWORD to NORMAL & vice versa

This is the full onClick handler for the Image/Button to show/hide the password.

    new OnClickListener() {
        public void onClick(View v) {
            // current ursor position
            int cursorPosition = edtPassword.getSelectionStart();

            // toggles the control variable
            isPassworsVisible = !isPassworsVisible;

            // sets the image toggler inside edit text
            passwordVisible.setImageDrawable(getResources().getDrawable(isPassworsVisible ? R.drawable.ic_eye_checked : R.drawable.ic_eye_unchecked));

            // apply input type
            edtPassword.setInputType(isPassworsVisible ? InputType.TYPE_TEXT_VARIATION_VISIBLE_PASSWORD : InputType.TYPE_CLASS_TEXT | InputType.TYPE_TEXT_VARIATION_PASSWORD);

            // returns cursor to position

jquery ui Dialog: cannot call methods on dialog prior to initialization

Try this instead

$(document).ready(function() {

You can also do:

var theDialog = $("#divDialog").dialog(opt);

That's because the dialog is not stored in $('#divDialog'), but on a new div that is created on the fly and returned by the .dialog(opt) function.

Accessing Arrays inside Arrays In PHP

Regarding your code: It's slightly hard to read... If you want to try to view it all in a php array format, just print_r it. This might help:

$a =

  'languages' =>    

  array (   

  76 =>      

 array (       'id' => '76',       'tag' => 'Deutsch',     ),   ),    'targets' =>    
 array (     81 =>      
 array (       'id' => '81',       'tag' => 'Deutschland',     ),   ),    'tags' =>    
 array (     7866 =>      
 array (       'id' => '7866',       'tag' => 'automobile',     ),     17800 =>      
 array (       'id' => '17800',       'tag' => 'seat leon',     ),     17801 =>      
 array (       'id' => '17801',       'tag' => 'seat leon cupra',     ),   ),   
'inactiveTags' =>    
 array (     195 =>      
 array (       'id' => '195',       'tag' => 'auto',     ),     17804 =>      
 array (       'id' => '17804',       'tag' => 'coupès',     ),     17805 =>      
 array (       'id' => '17805',       'tag' => 'fahrdynamik',     ),     901 =>      
 array (       'id' => '901',       'tag' => 'fahrzeuge',     ),     17802 =>      
 array (       'id' => '17802',       'tag' => 'günstige neuwagen',     ),     1991 =>      
 array (       'id' => '1991',       'tag' => 'motorsport',     ),     2154 =>      
 array (       'id' => '2154',       'tag' => 'neuwagen',     ),     10660 =>      
 array (       'id' => '10660',       'tag' => 'seat',     ),     17803 =>      
 array (       'id' => '17803',       'tag' => 'sportliche ausstrahlung',     ),     74 =>      
 array (       'id' => '74',       'tag' => 'web 2.0',     ),   ),    'categories' =>    
 array (     16082 =>      
 array (       'id' => '16082',       'tag' => 'Auto & Motorrad',     ),     51 =>      
 array (       'id' => '51',       'tag' => 'Blogosphäre',     ),     66 =>      
 array (       'id' => '66',       'tag' => 'Neues & Trends',     ),     68 =>      
 array (       'id' => '68',       'tag' => 'Privat',     ),   ), );

 function printarr($in){
 echo "\n";
 echo "\n";
 //run in php command line php path/to/file.php to test, switching otu the print_r.

How to make a simple image upload using Javascript/HTML

<img id="output_image" height=50px width=50px\
<input type="file" accept="image/*" onchange="preview_image(event)">

<script type"text/javascript">
  function preview_image(event) {
    var reader = new FileReader();
    reader.onload = function(){
      var output = document.getElementById('output_image');
      output.src = reader.result;

Insert data using Entity Framework model

var context = new DatabaseEntities();

var t = new test //Make sure you have a table called test in DB
    ID = Guid.NewGuid(),
    name = "blah",


Should do it

Paste in insert mode?

If you don't want Vim to mangle formatting in incoming pasted text, you might also want to consider using: :set paste. This will prevent Vim from re-tabbing your code. When done pasting, :set nopaste will return to the normal behavior.

It's also possible to toggle the mode with a single key, by adding something like set pastetoggle=<F2> to your .vimrc. More details on toggling auto-indent are here.

Writing String to Stream and reading it back does not work

You're using message.Length which returns the number of characters in the string, but you should be using the nubmer of bytes to read. You should use something like:

byte[] messageBytes = uniEncoding.GetBytes(message);
stringAsStream.Write(messageBytes, 0, messageBytes.Length);

You're then reading a single byte and expecting to get a character from it just by casting to char. UnicodeEncoding will use two bytes per character.

As Justin says you're also not seeking back to the beginning of the stream.

Basically I'm afraid pretty much everything is wrong here. Please give us the bigger picture and we can help you work out what you should really be doing. Using a StreamWriter to write and then a StreamReader to read is quite possibly what you want, but we can't really tell from just the brief bit of code you've shown.

libpng warning: iCCP: known incorrect sRGB profile

Extending the friederbluemle solution, download the pngcrush and then use the code like this if you are running it on multiple png files

path =r"C:\\project\\project\\images" # path to all .png images
import os

png_files =[]

for dirpath, subdirs, files in os.walk(path):
    for x in files:
        if x.endswith(".png"):
            png_files.append(os.path.join(dirpath, x))

file =r'C:\\Users\\user\\Downloads\\pngcrush_1_8_9_w64.exe' #pngcrush file 

for name in png_files:
    cmd = r'{} -ow -rem allb -reduce {}'.format(file,name)

here all the png file related to projects are in 1 folder.

How to restart a node.js server

At first open terminal/command line then go to your project directory, now install nodemon by using command npm install nodemon --save-dev this command will make sure it saved as developer dependency. If you are working with expressjs then in your package file it will look like

  "name": "expressjs-app",
  "version": "0.0.0",
  "private": true,
  "scripts": {
    "start": "node ./bin/www"
  "dependencies": {
    "cookie-parser": "~1.4.4",
    "debug": "~2.6.9",
    "express": "~4.16.1",
    "http-errors": "~1.6.3",
    "morgan": "~1.9.1",
    "pug": "^2.0.4"
  "devDependencies": {
    "nodemon": "^2.0.3"

now modify the "start" value in your package.json file, for production we will use the exsiting value but for development will use nodemon to track the changes in source file without restarting server. There for new value for start is "start": "if [[$NODE_ENV=='production']]; then node ./bin/www; else nodemon ./bin/www; fi"

final package.json file will look like

  "name": "expressjs-app",
  "version": "0.0.0",
  "private": true,
  "scripts": {
    "start": "if [[$NODE_ENV=='production']]; then node ./bin/www; else nodemon ./bin/www; fi"
  "dependencies": {
    "cookie-parser": "~1.4.4",
    "debug": "~2.6.9",
    "express": "~4.16.1",
    "http-errors": "~1.6.3",
    "morgan": "~1.9.1",
    "pug": "^2.0.4"
  "devDependencies": {
    "nodemon": "^2.0.3"

to uninstall nodemon jusy simply run the command npm uninstall nodemon

How can I make one python file run another?

You'd treat one of the files as a python module and make the other one import it (just as you import standard python modules). The latter can then refer to objects (including classes and functions) defined in the imported module. The module can also run whatever initialization code it needs. See

Create a new database with MySQL Workbench

This answer is for Ubuntu users looking for a solution without writing SQL queries.

The following is the initial screen you'll get after opening it

Initial screen

In the top right, where it says Administration, click in the arrow to the right

From Administration to Schemas

This will show Schema (instead of Administration) and it's possible to see a sys database.

Schema menu with databases

Right click in the grey area after functions and click Create Schema...

Create Schema

This will open the following where I'm creating a table named StackOverflow_db

Create new Schema

Clicking in the bottom right button that says "Apply",

Create a new Schema in Workbench

And in this new view click in "Apply" too. In the end you'll get a database called StackOverflow_db

Database created

Date constructor returns NaN in IE, but works in Firefox and Chrome

You can use the following code to parse ISO8601 date string:

function parseISO8601(d) {
    var timestamp = d;
    if (typeof (d) !== 'number') {
        timestamp = Date.parse(d);
    return new Date(timestamp);

Deleting multiple elements from a list

How about one of these (I'm very new to Python, but they seem ok):

ocean_basin = ['a', 'Atlantic', 'Pacific', 'Indian', 'a', 'a', 'a']
for i in range(1, (ocean_basin.count('a') + 1)):

['Atlantic', 'Pacific', 'Indian']

ob = ['a', 'b', 4, 5,'Atlantic', 'Pacific', 'Indian', 'a', 'a', 4, 'a']
remove = ('a', 'b', 4, 5)
ob = [i for i in ob if i not in (remove)]

['Atlantic', 'Pacific', 'Indian']

How does createOrReplaceTempView work in Spark?

SparkSQl support writing programs using Dataset and Dataframe API, along with it need to support sql.

In order to support Sql on DataFrames, first it requires a table definition with column names are required, along with if it creates tables the hive metastore will get lot unnecessary tables, because Spark-Sql natively resides on hive. So it will create a temporary view, which temporarily available in hive for time being and used as any other hive table, once the Spark Context stop it will be removed.

In order to create the view, developer need an utility called createOrReplaceTempView

Install opencv for Python 3.3

Here a solution for (I believe as seen by 'cp34' on the link below) Python 3.4.

Go to to

Download the appropriate .whl.

Go to the directory where the .whl is saved.

Use pip to install the .whl. e.g. pip install opencv_python-3.0.0-cp34-none-win_amd64.whl

Then just use import cv2.

CSS Grid Layout not working in IE11 even with prefixes

Michael has given a very comprehensive answer, but I'd like to point out a few things which you can still do to be able to use grids in IE in a nearly painless way.

The repeat functionality is supported

You can still use the repeat functionality, it's just hiding behind a different syntax. Instead of writing repeat(4, 1fr), you have to write (1fr)[4]. That's it. See this series of articles for the current state of affairs:

Supporting grid-gap

Grid gaps are supported in all browsers except IE. So you can use the @supports at-rule to set the grid-gaps conditionally for all new browsers:


.grid {
  display: grid;
.item {
  margin-right: 1rem;
  margin-bottom: 1rem;
@supports (grid-gap: 1rem) {
  .grid {
    grid-gap: 1rem;
  .item {
    margin-right: 0;
    margin-bottom: 0;

It's a little verbose, but on the plus side, you don't have to give up grids altogether just to support IE.

Use Autoprefixer

I can't stress this enough - half the pain of grids is solved just be using autoprefixer in your build step. Write your CSS in a standards-complaint way, and just let autoprefixer do it's job transforming all older spec properties automatically. When you decide you don't want to support IE, just change one line in the browserlist config and you'll have removed all IE-specific code from your built files.

How to get my project path?

This gives you the root folder:


You can navigate from here using .. or ./ etc.. , Appending .. takes you to folder where .sln file can be found

For .NET framework (thanks to Adiono comment)


For .NET core here is a way to do it (thanks to nopara73 comment)

Path.GetFullPath(Path.Combine(AppContext.BaseDirectory, "..\\..\\..\\")) ;

How do I get the backtrace for all the threads in GDB?

Generally, the backtrace is used to get the stack of the current thread, but if there is a necessity to get the stack trace of all the threads, use the following command.

thread apply all bt

How to tell if a JavaScript function is defined

if (callback && typeof(callback) == "function")

Note that callback (by itself) evaluates to false if it is undefined, null, 0, or false. Comparing to null is overly specific.

How to detect Ctrl+V, Ctrl+C using JavaScript?

Short solution for preventing user from using context menu, copy and cut in jQuery:

jQuery(document).bind("cut copy contextmenu",function(e){

Also disabling text selection in CSS might come handy:

.noselect {  
    -webkit-touch-callout: none;
    -webkit-user-select: none;
    -khtml-user-select: none;
    -moz-user-select: none;
    -ms-user-select: none;
     user-select: none;

Python - add PYTHONPATH during command line module run

 import sys
 sys.path.append('your certain directory')

Basically sys.path is a list with all the search paths for python modules. It is initialized by the interpreter. The content of PYTHONPATH is automatically added to the end of that list.

How to add Action bar options menu in Android Fragments

in AndroidManifest.xml set theme holo like this:

android:name="your Fragment or activity"
android:theme="@android:style/Theme.Holo" >

Transferring files over SSH

No, you still need to scp [from] [to] whichever way you're copying

The difference is, you need to scp -p server:serverpath localpath

How to create unique keys for React elements?

I am using this:

<div key={+new Date() + Math.random()}>

How add "or" in switch statements?

Case-statements automatically fall through if you don't specify otherwise (by writing break). Therefor you can write

   case 2:
   case 5:
      //your code

// etc... }

How to change the display name for LabelFor in razor in mvc3?

You could decorate your view model property with the [DisplayName] attribute and specify the text to be used:

[DisplayName("foo bar")]
public string SomekingStatus { get; set; }

Or use another overload of the LabelFor helper which allows you to specify the text:

@Html.LabelFor(model => model.SomekingStatus, "foo bar")

And, no, you cannot specify a class name in MVC3 as you tried to do, as the LabelFor helper doesn't support that. However, this would work in MVC4 or 5.

How to find the parent element using javascript

Using plain javascript:


In jQuery:


CRC32 C or C++ implementation

using zlib.h (

#include <zlib.h>
unsigned long  crc = crc32(0L, Z_NULL, 0);
crc = crc32(crc, (const unsigned char*)data_address, data_len);

Linq to Entities - SQL "IN" clause

Real example:

var trackList = Model.TrackingHistory.GroupBy(x => x.ShipmentStatusId).Select(x => x.Last()).Reverse();
List<int> done_step1 = new List<int>() {2,3,4,5,6,7,8,9,10,11,14,18,21,22,23,24,25,26 };
bool isExists = trackList.Where(x => done_step1.Contains(x.ShipmentStatusId.Value)).FirstOrDefault() != null;

How do I pull my project from github?

You Can do by Two ways,

1. Cloning the Remote Repo to your Local host

example: git clone

2. Pulling the Remote Repo to your Local host

First you have to create a git local repo by,

example: git init or git init repo-name then, git pull

That's all, All commits and branch in the remote repo now available in the local repository of your computer.

Happy Coding, cheers -:)

Is it possible to run JavaFX applications on iOS, Android or Windows Phone 8?

Possible. You can get commercial sport also.

JavaFXPorts is the name of the open source project maintained by Gluon that develops the code necessary for Java and JavaFX to run well on mobile and embedded hardware. The goal of this project is to contribute as much back to the OpenJFX project wherever possible, and when not possible, to maintain the minimal number of changes necessary to enable the goals of JavaFXPorts. Gluon takes the JavaFXPorts source code and compiles it into binaries ready for deployment onto iOS, Android, and embedded hardware. The JavaFXPorts builds are freely available on this website for all developers.

How to prevent the "Confirm Form Resubmission" dialog?

It seems you are looking for the Post/Redirect/Get pattern.

As another solution you may stop to use redirecting at all.

You may process and render the processing result at once with no POST confirmation alert. You should just manipulate the browser history object:

history.replaceState("", "", "/the/result/page")

See full or short answers

Haversine Formula in Python (Bearing and Distance between two GPS points)

The bearing calculation is incorrect, you need to swap the inputs to atan2.

    bearing = atan2(sin(long2-long1)*cos(lat2), cos(lat1)*sin(lat2)-sin(lat1)*cos(lat2)*cos(long2-long1))
    bearing = degrees(bearing)
    bearing = (bearing + 360) % 360

This will give you the correct bearing.

OS X Bash, 'watch' command

Or, in your ~/.bashrc file:

function watch {
    while :; do clear; date; echo; $@; sleep 2; done

Declare variable in SQLite and use it

I appreciate that the other solutions do not depend on any other software tool, but why not just use another programming language that can interface to SQLite such as C#, C++, Go, Haskell, Java, Lua, Python, or Rust?

How do I convert a String to a BigInteger?

Instead of using valueOf(long) and parse(), you can directly use the BigInteger constructor that takes a string argument:

BigInteger numBig = new BigInteger("8599825996872482982482982252524684268426846846846846849848418418414141841841984219848941984218942894298421984286289228927948728929829");

That should give you the desired value.

Printing Batch file results to a text file

For showing result of batch file in text file, you can use

this command

chdir > test.txt

This command will redirect result to test.txt.

When you open test.txt you will found current path of directory in test.txt

Get installed applications in a system

Iterate through "HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall" keys and check their "DisplayName" values.

How to simulate a click with JavaScript?

What about something simple like:


Supported even by IE.

PHP - Copy image to my server direct from URL

From Copy images from url to server, delete all images after

function getimg($url) {         
    $headers[] = 'Accept: image/gif, image/x-bitmap, image/jpeg, image/pjpeg';              
    $headers[] = 'Connection: Keep-Alive';         
    $headers[] = 'Content-type: application/x-www-form-urlencoded;charset=UTF-8';         
    $user_agent = 'php';         
    $process = curl_init($url);         
    curl_setopt($process, CURLOPT_HTTPHEADER, $headers);         
    curl_setopt($process, CURLOPT_HEADER, 0);         
    curl_setopt($process, CURLOPT_USERAGENT, $user_agent); //check here         
    curl_setopt($process, CURLOPT_TIMEOUT, 30);         
    curl_setopt($process, CURLOPT_RETURNTRANSFER, 1);         
    curl_setopt($process, CURLOPT_FOLLOWLOCATION, 1);         
    $return = curl_exec($process);         
    return $return;     

$imgurl = ''; 
$imagename= basename($imgurl);
$image = getimg($imgurl); 

Sublime Text 3 how to change the font size of the file sidebar?

I use Soda Dark 3 with icons enabled. So by just renaming it erases all the icons enabled with it. So I just leave the Default as it is and created a new file Soda Dark 3.sublime-theme and just have the following in the content

    "class": "label_control",
    "color": [150, 25, 25],
    "shadow_color": [24, 24, 24],
    "shadow_offset": [0, -1],
    "font.size": 16,
    "font.bold": true


So in Mac is it at /Users/gugovind/Library/Application Support/Sublime Text 3/Packages/User/

#1146 - Table 'phpmyadmin.pma_recent' doesn't exist

You have to run the create_tables.sql inside the examples/ folder on phpMyAdmin to create the tables needed for the advanced features. That or disable those features by commenting them on the config file.

URL for public Amazon S3 bucket

The URL structure you're referring to is called the REST endpoint, as opposed to the Web Site Endpoint.

Note: Since this answer was originally written, S3 has rolled out dualstack support on REST endpoints, using new hostnames, while leaving the existing hostnames in place. This is now integrated into the information provided, below.

If your bucket is really in the us-east-1 region of AWS -- which the S3 documentation formerly referred to as the "US Standard" region, but was subsequently officially renamed to the "U.S. East (N. Virginia) Region" -- then is not the correct form for that endpoint, even though it looks like it should be. The correct format for that region is either or

The format you're using is applicable to all the other S3 regions, but not US Standard US East (N. Virginia) [us-east-1].

S3 now also has dual-stack endpoint hostnames for the REST endpoints, and unlike the original endpoint hostnames, the names of these have a consistent format across regions, for example These endpoints support both IPv4 and IPv6 connectivity and DNS resolution, but are otherwise functionally equivalent to the existing REST endpoints.

If your permissions and configuration are set up such that the web site endpoint works, then the REST endpoint should work, too.

However... the two endpoints do not offer the same functionality.

Roughly speaking, the REST endpoint is better-suited for machine access and the web site endpoint is better suited for human access, since the web site endpoint offers friendly error messages, index documents, and redirects, while the REST endpoint doesn't. On the other hand, the REST endpoint offers HTTPS and support for signed URLs, while the web site endpoint doesn't.

Choose the correct type of endpoint (REST or web site) for your application:

¹ has been referred to as the "Northern Virginia endpoint," in contrast to the "Global endpoint" It was unofficially possible to get read-after-write consistency on new objects in this region if the "s3-external-1" hostname was used, because this would send you to a subset of possible physical endpoints that could provide that functionality. This behavior is now officially supported on this endpoint, so this is probably the better choice in many applications. Previously, s3-external-2 had been referred to as the "Pacific Northwest endpoint" for US-Standard, though it is now a CNAME in DNS for s3-external-1 so s3-external-2 appears to have no purpose except backwards-compatibility.

What is the difference between old style and new style classes in Python?

Old style classes are still marginally faster for attribute lookup. This is not usually important, but it may be useful in performance-sensitive Python 2.x code:

In [3]: class A:
   ...:     def __init__(self):
   ...:         self.a = 'hi there'

In [4]: class B(object):
   ...:     def __init__(self):
   ...:         self.a = 'hi there'

In [6]: aobj = A()
In [7]: bobj = B()

In [8]: %timeit aobj.a
10000000 loops, best of 3: 78.7 ns per loop

In [10]: %timeit bobj.a
10000000 loops, best of 3: 86.9 ns per loop

Setting an int to Infinity in C++

int is inherently finite; there's no value that satisfies your requirements.

If you're willing to change the type of b, though, you can do this with operator overrides:

class infinitytype {};

template<typename T>
bool operator>(const T &, const infinitytype &) {
  return false;

template<typename T>
bool operator<(const T &, const infinitytype &) {
  return true;

bool operator<(const infinitytype &, const infinitytype &) {
  return false;

bool operator>(const infinitytype &, const infinitytype &) {
  return false;

// add operator==, operator!=, operator>=, operator<=...

int main() {
  std::cout << ( INT_MAX < infinitytype() ); // true

Using `date` command to get previous, current and next month

If you happen to be using date in a MacOS environment, try this:

ST1:~ ejf$ date
Mon Feb 20 21:55:48 CST 2017
ST1:~ ejf$ date -v-1m +%m
ST1:~ ejf$ date -v+1m +%m

Also, I'd rather calculate the previous and next month on the first day of each month, this way you won't have issues with months ending the 30/31 or 28/29 (Feb/Feb leap year)

In Ruby on Rails, what's the difference between DateTime, Timestamp, Time and Date?

  1. :datetime (8 bytes)

    • Stores Date and Time formatted YYYY-MM-DD HH:MM:SS
    • Useful for columns like birth_date
  2. :timestamp (4 bytes)

    • Stores number of seconds since 1970-01-01
    • Useful for columns like updated_at, created_at
  3. :date (3 bytes)
    • Stores Date
  4. :time (3 bytes)
    • Stores Time

Setting values on a copy of a slice from a DataFrame

This warning comes because your dataframe x is a copy of a slice. This is not easy to know why, but it has something to do with how you have come to the current state of it.

You can either create a proper dataframe out of x by doing

x = x.copy()

This will remove the warning, but it is not the proper way

You should be using the DataFrame.loc method, as the warning suggests, like this:

x.loc[:,'Mass32s'] = pandas.rolling_mean(x.Mass32, 5).shift(-2)

Using pip behind a proxy with CNTLM

Under Windows dont forget to set

SET HTTPS_PROXY=<proxyHost>:<proxyPort>

what I needed to set for

pip install pep8

Filter element based on .data() key/value

We can make a plugin pretty easily:

$.fn.filterData = function(key, value) {
    return this.filter(function() {
        return $(this).data(key) == value;

Usage (checking a radio button):


forEach loop Java 8 for Map entry set

String ss = "Pawan kavita kiyansh Patidar Patidar";
    StringBuilder ress = new StringBuilder();
    Map<Character, Integer> fre = ss.chars().boxed()
            .collect(Collectors.toMap(k->Character.valueOf((char) k.intValue()),k->1,Integer::sum));
      //fre.forEach((k, v) -> System.out.println((k + ":" + v)));
    fre.entrySet().forEach(e ->{
            //System.out.println(e.getKey() + ":" + e.getValue());

        //System.out.println("Item : " + k + " Count : " + v);

What does if __name__ == "__main__": do?

You can make the file usable as a script as well as an importable module. (a module named fibo)

# Other modules can IMPORT this MODULE to use the function fib
def fib(n):    # write Fibonacci series up to n
    a, b = 0, 1
    while b < n:
        print(b, end=' ')
        a, b = b, a+b

# This allows the file to be used as a SCRIPT
if __name__ == "__main__":
    import sys


Best way to remove items from a collection

If it's an ICollection then you won't have a RemoveAll method. Here's an extension method that will do it:

    public static void RemoveAll<T>(this ICollection<T> source, 
                                    Func<T, bool> predicate)
        if (source == null)
            throw new ArgumentNullException("source", "source is null.");

        if (predicate == null)
            throw new ArgumentNullException("predicate", "predicate is null.");

        source.Where(predicate).ToList().ForEach(e => source.Remove(e));

Based on:

How do I escape double quotes in attributes in an XML String in T-SQL?

In Jelly.core to test a literal string one would use:

&lt;core:when test="${ name == 'ABC' }"&gt; 

But if I have to check for string "Toy's R Us":

&lt;core:when test="${ name == &amp;quot;Toy&apos;s R Us&amp;quot; }"&gt;

It would be like this, if the double quotes were allowed inside:

&lt;core:when test="${ name == "Toy's R Us" }"&gt; 

How to keep form values after post

If you are looking to just repopulate the fields with the values that were posted in them, then just echo the post value back into the field, like so:

<input type="text" name="myField1" value="<?php echo isset($_POST['myField1']) ? $_POST['myField1'] : '' ?>" />

Running two projects at once in Visual Studio

Max has the best solution for when you always want to start both projects, but you can also right click a project and choose menu Debug ? Start New Instance.

This is an option when you only occasionally need to start the second project or when you need to delay the start of the second project (maybe the server needs to get up and running before the client tries to connect, or something).

Add padding on view programmatically

To answer your second question:


like SpK and Jave suggested, will set the padding in pixels. You can set it in dp by calculating the dp value as follows:

int paddingDp = 25;
float density = context.getResources().getDisplayMetrics().density
int paddingPixel = (int)(paddingDp * density);

Hope that helps!

Insert a string at a specific index

  1. Instantiate an array from the string
  2. Use Array#splice
  3. Stringify again using Array#join

The benefits of this approach are two-fold:

  1. Simple
  2. Unicode code point compliant

const pair = Array.from('USDGBP')_x000D_
pair.splice(3, 0, '/')_x000D_

Annotation-specified bean name conflicts with existing, non-compatible bean def

If none of the other answers fix your problem and it started occurring after change any configuration direct or indirectly (via git pull / merge / rebase) and your project is a Maven project:

mvn clean

Hope this fixes your problem. Or someones

Java current machine name and logged in user?

Using is not secure as environment variables can be faked. Method you were using is good, there are similar methods for unix based OS as well

PHP & MySQL: mysqli_num_rows() expects parameter 1 to be mysqli_result, boolean given

The query either returned no rows or is erroneus, thus FALSE is returned. Change it to

if (!$dbc || mysqli_num_rows($dbc) == 0)


Return Values

Returns TRUE on success or FALSE on failure. For SELECT, SHOW, DESCRIBE or EXPLAIN mysqli_query() will return a result object.

Is it correct to use alt tag for an anchor link?

For anchors, you should use title instead. alt is not valid atribute of a. See

How to get a unique computer identifier in Java (like disk ID or motherboard ID)?

It is common to use the MAC address is associated with the network card.

The address is available in Java 6 through through the following API:

Java 6 Docs for Hardware Address

I haven't used it in Java, but for other network identification applications it has been helpful.

Inner Joining three tables

dbo.tableA AS A INNER JOIN dbo.TableB AS B
ON A.common = B.common INNER JOIN TableC C
ON B.common = C.common

Removing empty rows of a data file in R

Here are some dplyr options:

# sample data
df <- data.frame(a = c('1', NA, '3', NA), b = c('a', 'b', 'c', NA), c = c('e', 'f', 'g', NA))


# remove rows where all values are NA:
df %>% filter_all(any_vars(!
df %>% filter_all(any_vars(complete.cases(.)))  

# remove rows where only some values are NA:
df %>% filter_all(all_vars(!
df %>% filter_all(all_vars(complete.cases(.)))  

# or more succinctly:
df %>% filter(complete.cases(.))  
df %>% na.omit

# dplyr and tidyr:
df %>% drop_na

UnsupportedClassVersionError unsupported major.minor version 51.0 unable to load class

java_home environment variable should point to the location of the proper version of java installation directory, so that tomcat starts with the right version. for example it you built the project with java 1.7 , then make sure that JAVA_HOME environment variable points to the jdk 1.7 installation directory in your machine.

I had same problem , when i deploy the war in tomcat and run, the link throws the error. But pointing the variable - JAVA_HOME to jdk 1.7 resolved the issue, as my war file was built in java 1.7 environment.

Strangest language feature

In JavaScript:

2 == [2]

// Even stranger
2 == [[[2]]]

// And down-right nutty
var a = { "abc" : 1 };
a[[[["abc"]]]] === a["abc"]; // this is also true

Luckily the kind folks at explained the whole thing to me: Why does 2 == [2] in JavaScript?

Adding values to specific DataTable cells

You mean you want to add a new row and only put data in a certain column? Try the following:

var row = dataTable.NewRow();
row[myColumn].Value = "my new value";

As it is a data table, though, there will always be data of some kind in every column. It just might be DBNull.Value instead of whatever data type you imagine it would be.

ng-change get new value and original value

You can use a scope watch:

$scope.$watch('user', function(newValue, oldValue) {
  // access new and old value here
  console.log("Your former was "", you're current user name is "".");

Remove elements from collection while iterating

Let me give a few examples with some alternatives to avoid a ConcurrentModificationException.

Suppose we have the following collection of books

List<Book> books = new ArrayList<Book>();
books.add(new Book(new ISBN("0-201-63361-2")));
books.add(new Book(new ISBN("0-201-63361-3")));
books.add(new Book(new ISBN("0-201-63361-4")));

Collect and Remove

The first technique consists in collecting all the objects that we want to delete (e.g. using an enhanced for loop) and after we finish iterating, we remove all found objects.

ISBN isbn = new ISBN("0-201-63361-2");
List<Book> found = new ArrayList<Book>();
for(Book book : books){

This is supposing that the operation you want to do is "delete".

If you want to "add" this approach would also work, but I would assume you would iterate over a different collection to determine what elements you want to add to a second collection and then issue an addAll method at the end.

Using ListIterator

If you are working with lists, another technique consists in using a ListIterator which has support for removal and addition of items during the iteration itself.

ListIterator<Book> iter = books.listIterator();

Again, I used the "remove" method in the example above which is what your question seemed to imply, but you may also use its add method to add new elements during iteration.

Using JDK >= 8

For those working with Java 8 or superior versions, there are a couple of other techniques you could use to take advantage of it.

You could use the new removeIf method in the Collection base class:

ISBN other = new ISBN("0-201-63361-2");
books.removeIf(b -> b.getIsbn().equals(other));

Or use the new stream API:

ISBN other = new ISBN("0-201-63361-2");
List<Book> filtered =
                           .filter(b -> b.getIsbn().equals(other))

In this last case, to filter elements out of a collection, you reassign the original reference to the filtered collection (i.e. books = filtered) or used the filtered collection to removeAll the found elements from the original collection (i.e. books.removeAll(filtered)).

Use Sublist or Subset

There are other alternatives as well. If the list is sorted, and you want to remove consecutive elements you can create a sublist and then clear it:


Since the sublist is backed by the original list this would be an efficient way of removing this subcollection of elements.

Something similar could be achieved with sorted sets using NavigableSet.subSet method, or any of the slicing methods offered there.


What method you use might depend on what you are intending to do

  • The collect and removeAl technique works with any Collection (Collection, List, Set, etc).
  • The ListIterator technique obviously only works with lists, provided that their given ListIterator implementation offers support for add and remove operations.
  • The Iterator approach would work with any type of collection, but it only supports remove operations.
  • With the ListIterator/Iterator approach the obvious advantage is not having to copy anything since we remove as we iterate. So, this is very efficient.
  • The JDK 8 streams example don't actually removed anything, but looked for the desired elements, and then we replaced the original collection reference with the new one, and let the old one be garbage collected. So, we iterate only once over the collection and that would be efficient.
  • In the collect and removeAll approach the disadvantage is that we have to iterate twice. First we iterate in the foor-loop looking for an object that matches our removal criteria, and once we have found it, we ask to remove it from the original collection, which would imply a second iteration work to look for this item in order to remove it.
  • I think it is worth mentioning that the remove method of the Iterator interface is marked as "optional" in Javadocs, which means that there could be Iterator implementations that throw UnsupportedOperationException if we invoke the remove method. As such, I'd say this approach is less safe than others if we cannot guarantee the iterator support for removal of elements.

Beautiful way to remove GET-variables with PHP?

Another solution... I find this function more elegant, it will also remove the trailing '?' if the key to remove is the only one in the query string.

 * Remove a query string parameter from an URL.
 * @param string $url
 * @param string $varname
 * @return string
function removeQueryStringParameter($url, $varname)
    $parsedUrl = parse_url($url);
    $query = array();

    if (isset($parsedUrl['query'])) {
        parse_str($parsedUrl['query'], $query);

    $path = isset($parsedUrl['path']) ? $parsedUrl['path'] : '';
    $query = !empty($query) ? '?'. http_build_query($query) : '';

    return $parsedUrl['scheme']. '://'. $parsedUrl['host']. $path. $query;


$urls = array(

foreach ($urls as $url) {
    echo $url. '<br/>';
    echo removeQueryStringParameter($url, 'test'). '<br/><br/>';

Will output:

» Run these tests on 3v4l

Android SDK is missing, out of date, or is missing templates. Please ensure you are using SDK version 22 or later

I had same issue in Android Studio 3. (the project was open) so I closed the current project and the IDE automatically prompted to download the latest components. once its done everything was working correctly.


The canonical T-SQL (SqlServer) answer is to use a DELETE with JOIN as such

FROM Orders o
INNER JOIN Customers c
    ON o.CustomerId = c.CustomerId
WHERE c.FirstName = 'sklivvz'

This will delete all orders which have a customer with first name Sklivvz.

Set a DateTime database field to "Now"

In SQL you need to use GETDATE():

UPDATE table SET date = GETDATE();

There is no NOW() function.

To answer your question:

In a large table, since the function is evaluated for each row, you will end up getting different values for the updated field.

So, if your requirement is to set it all to the same date I would do something like this (untested):

SET @currDate = GETDATE();

UPDATE table SET date = @currDate;

How to use a variable for a key in a JavaScript object literal?

You could do the following for ES5:

var theTop = 'top'
  JSON.parse('{"' + theTop + '":' + JSON.stringify(10) + '}'), 10

Or extract to a function:

function newObj (key, value) {
  return JSON.parse('{"' + key + '":' + JSON.stringify(value) + '}')

var theTop = 'top'
  newObj(theTop, 10), 10

Can I change the headers of the HTTP request sent by the browser?

I was looking to do exactly the same thing (RESTful web service), and I stumbled upon this firefox addon, which lets you modify the accept headers (actually, any request headers) for requests. It works perfectly.

Python error: AttributeError: 'module' object has no attribute

More accurately, your mod1 and lib directories are not modules, they are packages. The file is a module.

Python does not automatically import subpackages or modules. You have to explicitly do it, or "cheat" by adding import statements in the initializers.

>>> import lib
>>> dir(lib)
['__builtins__', '__doc__', '__file__', '__name__', '__package__', '__path__']
>>> import lib.pkg1
>>> import lib.pkg1.mod11
>>> lib.pkg1.mod11.mod12()

An alternative is to use the from syntax to "pull" a module from a package into you scripts namespace.

>>> from lib.pkg1 import mod11

Then reference the function as simply mod11.mod12().

How to get client IP address in Laravel 5+

If you are under a load balancer, Laravel's \Request::ip() always returns the balancer's IP:

            echo $request->ip();
            // server ip

            echo \Request::ip();
            // server ip

            echo \request()->ip();
            // server ip

            echo $this->getIp(); //see the method below
            // clent ip

This custom method returns the real client ip:

public function getIp(){
        if (array_key_exists($key, $_SERVER) === true){
            foreach (explode(',', $_SERVER[$key]) as $ip){
                $ip = trim($ip); // just to be safe
                if (filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_NO_PRIV_RANGE | FILTER_FLAG_NO_RES_RANGE) !== false){
                    return $ip;
    return request()->ip(); // it will return server ip when no client ip found

In addition to this I suggest you to be very careful using Laravel's throttle middleware: It uses Laravel's Request::ip() as well, so all your visitors will be identified as the same user and you will hit the throttle limit very quickly. I experienced this live and this caused big issues.

To fix this:


    public function ip()
        //return $this->getClientIp(); //original method
        return $this->getIp(); // the above method

You can now also use Request::ip(), which should return the real IP in production.

What does "'') " mean in Flask

To answer to your second question. You can just hit the IP address of the machine that your flask app is running, e.g. in a browser on different machine on the same network and you are there. Though, you will not be able to access it if you are on a different network. Firewalls or VLans can cause you problems with reaching your application. If that computer has a public IP, then you can hit that IP from anywhere on the planet and you will be able to reach the app. Usually this might impose some configuration, since most of the public servers are behind some sort of router or firewall.

How to copy text programmatically in my Android app?

For Kotlin use the below code inside the activity.

import android.content.ClipboardManager

 val clipBoard = getSystemService(Context.CLIPBOARD_SERVICE) as ClipboardManager
 val clipData = ClipData.newPlainText("label","Message to be Copied")

Undefined reference to `sin`

I have the problem anyway with -lm added

gcc -Wall -lm mtest.c -o mtest.o
mtest.c: In function 'f1':
mtest.c:6:12: warning: unused variable 'res' [-Wunused-variable]
/tmp/cc925Nmf.o: In function `f1':
mtest.c:(.text+0x19): undefined reference to `sin'
collect2: ld returned 1 exit status

I discovered recently that it does not work if you first specify -lm. The order matters:

gcc mtest.c -o mtest.o -lm

Just link without problems

So you must specify the libraries after.

Find the last time table was updated

Find last time of update on a table

sys.dm_db_index_usage_stats ius INNER JOIN
sys.tables tbl ON (tbl.OBJECT_ID = ius.OBJECT_ID)
WHERE ius.database_id = DB_ID()

How to see remote tags?

Even without cloning or fetching, you can check the list of tags on the upstream repo with git ls-remote:

git ls-remote --tags /url/to/upstream/repo

(as illustrated in "When listing git-ls-remote why there's “^{}” after the tag name?")

xbmono illustrates in the comments that quotes are needed:

git ls-remote --tags /some/url/to/repo "refs/tags/MyTag^{}"

Note that you can always push your commits and tags in one command with (git 1.8.3+, April 2013):

git push --follow-tags

See Push git commits & tags simultaneously.

Regarding Atlassian SourceTree specifically:

Note that, from this thread, SourceTree ONLY shows local tags.

There is an RFE (Request for Enhancement) logged in SRCTREEWIN-4015 since Dec. 2015.

A simple workaround:

see a list of only unpushed tags?

git push --tags

or check the "Push all tags" box on the "Push" dialog box, all tags will be pushed to your remote.

That way, you will be "sure that they are present in remote so that other developers can pull them".

What is HTTP "Host" header?

The Host Header tells the webserver which virtual host to use (if set up). You can even have the same virtual host using several aliases (= domains and wildcard-domains). In this case, you still have the possibility to read that header manually in your web app if you want to provide different behavior based on different domains addressed. This is possible because in your webserver you can (and if I'm not mistaken you must) set up one vhost to be the default host. This default vhost is used whenever the host header does not match any of the configured virtual hosts.

That means: You get it right, although saying "multiple hosts" may be somewhat misleading: The host (the addressed machine) is the same, what really gets resolved to the IP address are different domain names (including subdomains) that are also referred to as hostnames (but not hosts!).

Although not part of the question, a fun fact: This specification led to problems with SSL in early days because the web server has to deliver the certificate that corresponds to the domain the client has addressed. However, in order to know what certificate to use, the webserver should have known the addressed hostname in advance. But because the client sends that information only over the encrypted channel (which means: after the certificate has already been sent), the server had to assume you browsed the default host. That meant one ssl-secured domain per IP address / port-combination.

This has been overcome with Server Name Indication; however, that again breaks some privacy, as the server name is now transferred in plain text again, so every man-in-the-middle would see which hostname you are trying to connect to.

Although the webserver would know the hostname from Server Name Indication, the Host header is not obsolete, because the Server Name Indication information is only used within the TLS handshake. With an unsecured connection, there is no Server Name Indication at all, so the Host header is still valid (and necessary).

Another fun fact: Most webservers (if not all) reject your HTTP request if it does not contain exactly one Host header, even if it could be omitted because there is only the default vhost configured. That means the minimum required information in an http-(get-)request is the first line containing METHOD RESOURCE and PROTOCOL VERSION and at least the Host header, like this:

GET /someresource.html HTTP/1.1

In the MDN Documentation on the "Host" header they actually phrase it like this:

A Host header field must be sent in all HTTP/1.1 request messages. A 400 (Bad Request) status code will be sent to any HTTP/1.1 request message that lacks a Host header field or contains more than one.

As mentioned by Darrel Miller, the complete specs can be found in RFC7230.

How to make an element in XML schema optional?

Set the minOccurs attribute to 0 in the schema like so:

<?xml version="1.0"?>
  <xs:schema version="1.0" xmlns:xs="" elementFormDefault="qualified">
    <xs:element name="request">
                <xs:element name="amenity">
                            <xs:element name="description" type="xs:string" minOccurs="0" />
    </xs:element> </xs:schema>

Joining two table entities in Spring Data JPA

@Query("SELECT rd FROM ReleaseDateType rd, CacheMedia cm WHERE ...")

Argparse optional positional arguments?

Use nargs='?' (or nargs='*' if you need more than one dir)

parser.add_argument('dir', nargs='?', default=os.getcwd())

extended example:

>>> import os, argparse
>>> parser = argparse.ArgumentParser()
>>> parser.add_argument('-v', action='store_true')
_StoreTrueAction(option_strings=['-v'], dest='v', nargs=0, const=True, default=False, type=None, choices=None, help=None, metavar=None)
>>> parser.add_argument('dir', nargs='?', default=os.getcwd())
_StoreAction(option_strings=[], dest='dir', nargs='?', const=None, default='/home/vinay', type=None, choices=None, help=None, metavar=None)
>>> parser.parse_args('somedir -v'.split())
Namespace(dir='somedir', v=True)
>>> parser.parse_args('-v'.split())
Namespace(dir='/home/vinay', v=True)
>>> parser.parse_args(''.split())
Namespace(dir='/home/vinay', v=False)
>>> parser.parse_args(['somedir'])
Namespace(dir='somedir', v=False)
>>> parser.parse_args('somedir -h -v'.split())
usage: [-h] [-v] [dir]

positional arguments:

optional arguments:
  -h, --help  show this help message and exit

$ is not a function - jQuery error

When jQuery is not present you get $ is undefined and not your message.

Did you check if you don't have a variable called $ somewhere before your code?
Inspect the value of $ in firebug to see what it is.

Slightly out of the question, but I can't resist to write a shorter code to your class assignment:

    var i = 1;
    $("ol li").each(function(){
        $(this).addClass('olli' + i++);

Android Webview - Webpage should fit the device screen

I had video in html string, and width of web view was larger that screen width and this is working for me.

Add these lines to HTML string.

<meta name="viewport" content="width=device-width">

Result after adding above code to HTML string:

<!DOCTYPE html>

<meta name="viewport" content="width=device-width">


How to get a Char from an ASCII Character Code in c#

Two options:

char c1 = '\u0001';
char c1 = (char) 1;

In a Git repository, how to properly rename a directory?

You can rename the directory using the file system. Then you can do git rm <old directory> and git add <new directory> (Help page). Then you can commit and push.

Git will detect that the contents are the same and that it's just a rename operation, and it'll appear as a rename entry in the history. You can check that this is the case before the commit using git status

Renaming files using node.js

For synchronous renaming use fs.renameSync

fs.renameSync('/path/to/Afghanistan.png', '/path/to/AF.png');

How to implement a SQL like 'LIKE' operator in java?

You could turn '%string%' to contains(), 'string%' to startsWith() and '%string"' to endsWith().

You should also run toLowerCase() on both the string and pattern as LIKE is case-insenstive.

Not sure how you'd handle '%string%other%' except with a Regular Expression though.

If you're using Regular Expressions:

FloatingActionButton example with Support Library

FloatingActionButton extends ImageView. So, it's simple as like introducing an ImageView in your layout. Here is an XML sample.

<   xmlns:app=""

app:borderWidth="0dp" is added as a workaround for elevation issues.

How to delete a file via PHP?

The following should help

  • realpath — Returns canonicalized absolute pathname
  • is_writable — Tells whether the filename is writable
  • unlink — Deletes a file

Run your filepath through realpath, then check if the returned path is writable and if so, unlink it.

Regular Expressions- Match Anything

I recommend use /(?=.*...)/g


const text1 = 'I am using regex';
/(?=.*regex)/g.test(text1) // true

const text2 = 'regex is awesome';
/(?=.*regex)/g.test(text2) // true

const text3 = 'regex is util';
/(?=.*util)(?=.*regex)/g.test(text3) // true

const text4 = 'util is necessary';
/(?=.*util)(?=.*regex)/g.test(text4) // false because need regex in text

Use regex101 to test

addClass and removeClass in jQuery - not removing class

The issue is caused because of event bubbling. The first part of your code to add .grown works fine.

The second part "removing grown class" on clicking the link doesn't work as expected as both the handler for .close_button and .clickable are executed. So it removes and readd the grown class to the div.

You can avoid this by using e.stopPropagation() inside .close_button click handler to avoid the event from bubbling.


Full Code

$(document).on('click', '.clickable', function () {
}).on('click', '.close_button', function (e) {

Difference between app.use and app.get in express.js

In addition to the above explanations, what I experience:

app.use('/book', handler);  

will match all requests beginning with '/book' as URL. so it also matches '/book/1' or '/book/2'


matches only GET request with exact match. It will not handle URLs like '/book/1' or '/book/2'

So, if you want a global handler that handles all of your routes, then app.use('/') is the option. app.get('/') will handle only the root URL.

Using SSH keys inside docker container

This issue is really an annoying one. Since you can't add/copy any file outside the dockerfile context, which means it's impossible to just link ~/.ssh/id_rsa into image's /root/.ssh/id_rsa, and when you definitely need a key to do some sshed thing like git clone from a private repo link..., during the building of your docker image.

Anyways, I found a solution to workaround, not so persuading but did work for me.

  1. in your dockerfile:

    • add this file as /root/.ssh/id_rsa
    • do what you want, such as git clone, composer...
    • rm /root/.ssh/id_rsa at the end
  2. a script to do in one shoot:

    • cp your key to the folder holding dockerfile
    • docker build
    • rm the copied key
  3. anytime you have to run a container from this image with some ssh requirements, just add -v for the run command, like:

    docker run -v ~/.ssh/id_rsa:/root/.ssh/id_rsa --name container image command

This solution results in no private key in both you project source and the built docker image, so no security issue to worry about anymore.

How do I negate a condition in PowerShell?

if you don't like the double brackets or you don't want to write a function, you can just use a variable.

$path = Test-Path C:\Code
if (!$path) {
    write "it doesn't exist!"

show and hide divs based on radio button click

You were pretty close. You're description div tags didn't have the .desc class defined. For your scenario you should have the radio button value equal to the div that you're trying to show.


<div id="myRadioGroup">

    2 Cars<input type="radio" name="cars" checked="checked" value="twoCarDiv"  />

    3 Cars<input type="radio" name="cars" value="threeCarDiv" />

    <div id="twoCarDiv" class="desc">
        2 Cars Selected
    <div id="threeCarDiv" class="desc">
        3 Cars Selected


$(document).ready(function() {
    $("input[name$='cars']").click(function() {
        var test = $(this).val();
        $("#" + test).show();

working example:

Sort a list of numerical strings in ascending order

in python sorted works like you want with integers:

>>> sorted([10,3,2])
[2, 3, 10]

it looks like you have a problem because you are using strings:

>>> sorted(['10','3','2'])
['10', '2', '3']

(because string ordering starts with the first character, and "1" comes before "2", no matter what characters follow) which can be fixed with key=int

>>> sorted(['10','3','2'], key=int)
['2', '3', '10']

which converts the values to integers during the sort (it is called as a function - int('10') returns the integer 10)

and as suggested in the comments, you can also sort the list itself, rather than generating a new one:

>>> l = ['10','3','2']
>>> l.sort(key=int)
>>> l
['2', '3', '10']

but i would look into why you have strings at all. you should be able to save and retrieve integers. it looks like you are saving a string when you should be saving an int? (sqlite is unusual amongst databases, in that it kind-of stores data in the same type as it is given, even if the table column type is different).

and once you start saving integers, you can also get the list back sorted from sqlite by adding order by ... to the sql command:

select temperature from temperatures order by temperature;

How to reset the state of a Redux store?

A quick and easy option which worked for me was using redux-reset . Which was straightforward and also has some advanced options, for larger apps.

Setup in create store

import reduxReset from 'redux-reset'
const enHanceCreateStore = compose(
reduxReset()  // Will use 'RESET' as default action.type to trigger reset
const store = enHanceCreateStore(reducers)

Dispatch your 'reset' in your logout function

type: 'RESET'

Hope this helps

PHP mail not working for some reason

If you are using Ubuntu and it seem sendmail is not in /usr/sbin/sendmail, install sendmail using the terminal with this command:

sudo apt-get install sendmail

and then run reload the PHP page where mail() is written. Also check your spam folder.

What is Bit Masking?

Masking means to keep/change/remove a desired part of information. Lets see an image-masking operation; like- this masking operation is removing any thing that is not skin-

enter image description here

We are doing AND operation in this example. There are also other masking operators- OR, XOR.

Bit-Masking means imposing mask over bits. Here is a bit-masking with AND-

     1 1 1 0 1 1 0 1   [input]
(&)  0 0 1 1 1 1 0 0    [mask]
     0 0 1 0 1 1 0 0  [output]

So, only the middle 4 bits (as these bits are 1 in this mask) remain.

Lets see this with XOR-

     1 1 1 0 1 1 0 1   [input]
(^)  0 0 1 1 1 1 0 0    [mask]
     1 1 0 1 0 0 0 1  [output]

Now, the middle 4 bits are flipped (1 became 0, 0 became 1).

So, using bit-mask we can access individual bits [examples]. Sometimes, this technique may also be used for improving performance. Take this for example-

bool isOdd(int i) {
    return i%2;

This function tells if an integer is odd/even. We can achieve the same result with more efficiency using bit-mask-

bool isOdd(int i) {
    return i&1;

Short Explanation: If the least significant bit of a binary number is 1 then it is odd; for 0 it will be even. So, by doing AND with 1 we are removing all other bits except for the least significant bit i.e.:

     55  ->  0 0 1 1 0 1 1 1   [input]
(&)   1  ->  0 0 0 0 0 0 0 1    [mask]
      1  <-  0 0 0 0 0 0 0 1  [output]

Using continue in a switch statement

Switch is not considered as loop so you cannot use Continue inside a case statement in switch...

IIS7 folder permissions for web application

If it's any help to anyone, give permission to "IIS_IUSRS" group.

Note that if you can't find "IIS_IUSRS", try prepending it with your server's name, like "MySexyServer\IIS_IUSRS".

Convert timestamp to string

try this

SimpleDateFormat dateFormat = new SimpleDateFormat("dd-MM-yyyy HH:mm:ss");
String string  = dateFormat.format(new Date());

you can create any format see this

Android requires compiler compliance level 5.0 or 6.0. Found '1.7' instead. Please use Android Tools > Fix Project Properties

That isn't the problem, Jack. Android SDK isn't x64, but works ok with x64 jvm (and x64 eclipse IDE).

As helios said, you must set project compatibility to Java 5.0 or Java 6.0.

To do that, 2 options:

  1. Right-click on your project and select "Android Tools -> Fix Project Properties" (if this din't work, try second option)
  2. Right-click on your project and select "Properties -> Java Compiler", check "Enable project specific settings" and select 1.5 or 1.6 from "Compiler compliance settings" select box.

ImportError: No module named matplotlib.pyplot

If you are using Python 2, just run

sudo apt-get install python-matplotlib

The best way to get matplotlib is :

pip install matplotlib

cause the previous way may give you a old version of matplotlib

Camera access through browser

As of 2015, it now just works.

<input type="file">

This will ask user for the upload of any file. On iOS 8.x this can be a camera video, camera photo, or a photo/video from Photo Library.

iOS/iPhone photo/video/file upload

<input type="file" accept="image/*">

This is as above, but limits the uploads to photos only from camera or library, no videos.

Python speed testing - Time Difference - milliseconds

Arrow: Better dates & times for Python

import arrow
start_time = arrow.utcnow()
end_time = arrow.utcnow()
(end_time - start_time).total_seconds()  # senconds
(end_time - start_time).total_seconds() * 1000  # milliseconds

How to read file with async/await properly?

You can easily wrap the readFile command with a promise like so:

async function readFile(path) {
    return new Promise((resolve, reject) => {
      fs.readFile(path, 'utf8', function (err, data) {
        if (err) {

then use:

await readFile("path/to/file");

How to send an email with Gmail as provider using Python?

    import smtplib

    fromadd='[email protected]'
    toadd='[email protected]'

    msg='''hi,how r u'''
    username='[email protected]'

        server = smtplib.SMTP('')

        print("Mail Send Successfully")

        print("Error:unable to send mail")

   NOTE: that                                                         should be enabled

Chrome & Safari Error::Not allowed to load local resource: file:///D:/CSS/Style.css

You wont be able to access a local resource from your aspx page (web server). Have you tried a relative path from your aspx page to your css file like so...

<link rel="stylesheet" media="all" href="/CSS/Style.css" type="text/css" />

The above assumes that you have a folder called CSS in the root of your website like this:

Check if datetime instance falls in between other two datetime objects

You can, use:

if (date >= startDate && date<= EndDate) { return true; }

How to properly express JPQL "join fetch" with "where" clause as JPA 2 CriteriaQuery?

I will show visually the problem, using the great example from James answer and adding the alternative solution.

When you do the follow query, without the FETCH:

Select e from Employee e 
join e.phones p 
where p.areaCode = '613'

You will have the follow results from Employee as you expected:

EmployeeId EmployeeName PhoneId PhoneAreaCode
1 James 5 613
1 James 6 416

But when you add the FETCH word on JOIN, this is what happens:

EmployeeId EmployeeName PhoneId PhoneAreaCode
1 James 5 613

The generated SQL is the same for the two queries, but the Hibernate removes on memory the 416 register when you use WHERE on the FETCH join.

So, to bring all phones and apply the WHERE correctly, you need to have two JOINs: one for the WHERE and another for the FETCH. Like:

Select e from Employee e 
join e.phones p 
join fetch e.phones      //no alias, to not commit the mistake
where p.areaCode = '613'

Git pull - Please move or remove them before you can merge

If you are getting error like

  • branch master -> FETCH_HEAD error: The following untracked working tree files would be overwritten by merge: src/dj/abc.html Please move or remove them before you merge. Aborting

Try removing the above file manually(Careful). Git will merge this file from master branch.

Standard Android Button with a different color

Mike, you might be interested in color filters.

An example:

button.getBackground().setColorFilter(new LightingColorFilter(0xFFFFFFFF, 0xFFAA0000));

try this to achieve the color you want.

Cross browser method to fit a child div to its parent's width

If you put position:relative; on the outer element, the inner element will place itself according to this one. Then a width:auto; on the inner element will be the same as the width of the outer.

python variable NameError

Initialize tSize to

tSize = ""  

before your if block to be safe. Also in your else case, put tSize in quotes so it is a string not an int. Also also you are comparing strings to ints.