Programs & Examples On #Docstring

How do I disable "missing docstring" warnings at a file-level in Pylint?

In my case, with Pylint 2.6.0, the missing docstring messages wouldn't disappear, even after explicitly disabling missing-module-docstring, missing-class-docstring and missing-function-docstring in my .pylintrc file. Finally, the following configuration worked for me:



Apparently, Pylint 2.6.0 still validates docstrings unless both checks are disabled.

What is the standard Python docstring format?

PEP-8 is the official python coding standard. It contains a section on docstrings, which refers to PEP-257 -- a complete specification for docstrings.

How to document Python code using Doxygen

The doxypy input filter allows you to use pretty much all of Doxygen's formatting tags in a standard Python docstring format. I use it to document a large mixed C++ and Python game application framework, and it's working well.

"Expected an indented block" error?

You have to indent the docstring after the function definition there (line 3, 4):

def print_lol(the_list):
"""this doesn't works"""
    print 'Ain't happening'


def print_lol(the_list):
    """this works!"""
    print 'Aaaand it's happening'

Or you can use # to comment instead:

def print_lol(the_list):
#this works, too!
    print 'Hohoho'

Also, you can see PEP 257 about docstrings.

Hope this helps!

How to comment out a block of code in Python

In vi:

  • Go to top of block and mark it with letter a.
  • Go to bottom of block and mark it with letter b

Then do

:'a,'b s!^!#!

Bootstrap modal opening on page load

I found the problem. This code was placed in a separate file that was added with a php include() function. And this include was happening before the Bootstrap files were loaded. So the Bootstrap JS file was not loaded yet, causing this modal to not do anything.

With the above code sample is nothing wrong and works as intended when placed in the body part of a html page.

<script type="text/javascript">

How to Parse JSON Array with Gson

You can easily do this in Kotlin using the following code:

val fileData = "your_json_string"
val gson = GsonBuilder().create()
val packagesArray = gson.fromJson(fileData , Array<YourClass>

Basically, you only need to provide an Array of YourClass objects.

How to view Plugin Manager in Notepad++

To install a plugin without Plugin Manager:

  1. Download your plugin and extract contents in a folder. You will find a .dll file inside. Copy it.
  2. Open C:\Program Files (x86)\Notepad++\pluginsand paste the .dll
  3. Run Notepad++

Reading local text file into a JavaScript array

Using Node.js

sync mode:

var fs = require("fs");
var text = fs.readFileSync("./mytext.txt");
var textByLine = text.split("\n")

async mode:

var fs = require("fs");
fs.readFile("./mytext.txt", function(text){
    var textByLine = text.split("\n")


As of at least Node 6, readFileSync returns a Buffer, so it must first be converted to a string in order for split to work:

var text = fs.readFileSync("./mytext.txt").toString('utf-8');


var text = fs.readFileSync("./mytext.txt", "utf-8");

"Correct" way to specifiy optional arguments in R functions

You could also use missing() to test whether or not the argument y was supplied:

fooBar <- function(x,y){
    if(missing(y)) {
    } else {
        x + y

# [1] 4.5
# [1] 3

Accessing private member variables from prototype-defined functions

No, there's no way to do it. That would essentially be scoping in reverse.

Methods defined inside the constructor have access to private variables because all functions have access to the scope in which they were defined.

Methods defined on a prototype are not defined within the scope of the constructor, and will not have access to the constructor's local variables.

You can still have private variables, but if you want methods defined on the prototype to have access to them, you should define getters and setters on the this object, which the prototype methods (along with everything else) will have access to. For example:

function Person(name, secret) {
    // public = name;

    // private
    var secret = secret;

    // public methods have access to private members
    this.setSecret = function(s) {
        secret = s;

    this.getSecret = function() {
        return secret;

// Must use getters/setters 
Person.prototype.spillSecret = function() { alert(this.getSecret()); };

Pushing from local repository to GitHub hosted remote

You push your local repository to the remote repository using the git push command after first establishing a relationship between the two with the git remote add [alias] [url] command. If you visit your Github repository, it will show you the URL to use for pushing. You'll first enter something like:

git remote add origin [email protected]:username/reponame.git

Unless you started by running git clone against the remote repository, in which case this step has been done for you already.

And after that, you'll type:

git push origin master

After your first push, you can simply type:

git push

when you want to update the remote repository in the future.

How to force Chrome's script debugger to reload javascript?

If you are making local changes to a javascript in the Developer Tools, you need to make sure that you turn OFF those changes before reloading the page.

In the Sources tab, with your script open, right-click in your script and click the "Local Modifications" option from the context menu. That brings up the list of scripts you've saved modifications to. If you see it in that window, Developer Tools will always keep your local copy rather than refreshing it from the server. Click the "revert" button, then refresh again, and you should get the fresh copy.

date() method, "A non well formed numeric value encountered" does not want to format a date passed in $_POST

From the documentation for strtotime():

Dates in the m/d/y or d-m-y formats are disambiguated by looking at the separator between the various components: if the separator is a slash (/), then the American m/d/y is assumed; whereas if the separator is a dash (-) or a dot (.), then the European d-m-y format is assumed.

In your date string, you have 12-16-2013. 16 isn't a valid month, and hence strtotime() returns false.

Since you can't use DateTime class, you could manually replace the - with / using str_replace() to convert the date string into a format that strtotime() understands:

$date = '2-16-2013';
echo date('Y-m-d', strtotime(str_replace('-','/', $date))); // => 2013-02-16

How to add image in Flutter

An alternative way to put images in your app (for me it just worked that way):

1 - Create an assets/images folder

2 - Add your image to the new folder

3 - Register the assets folder in pubspec.yaml

4 - Use this code:

import 'package:flutter/material.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  Widget build(BuildContext context) {

    var assetsImage = new AssetImage('assets/images/mountain.jpg'); //<- Creates an object that fetches an image.
    var image = new Image(image: assetsImage, fit: BoxFit.cover); //<- Creates a widget that displays an image.

    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: Text("Climb your mountain!"),
          backgroundColor: Colors.amber[600], //<- background color to combine with the picture :-)
        body: Container(child: image), //<- place where the image appears

Climb your mountain!

How do you Make A Repeat-Until Loop in C++?

  //  whatever
} while ( !condition );

Check if object exists in JavaScript

zero and null are implicit pointers. If you arn't doing arithmetic, comparing, or printing '0' to screen there is no need to actually type it. Its implicit. As in implied. Typeof is also not required for the same reason. Watch.

if(obj) console.log("exists");

I didn't see request for a not or else there for it is not included as. As much as i love extra content which doesn't fit into the question. Lets keep it simple.

How to capitalize the first letter of a String in Java?

To capitalize the first letter of the input string, we first split the string on space and then use the collection transformation procedure provided by map

<T, R> Array<out T>.map(

   transform: (T) -> R

): List<R>

to transform, each split string to first in lowercase then capitalize the first letter. This map transformation will return a list that needs to convert into a string by using joinToString function.


fun main() {
     * Program that first convert all uper case into lower case then 
     * convert fist letter into uppercase
    val str = "aLi AzAZ alam"
    val calStr = str.split(" ").map{it.toLowerCase().capitalize()}
    println(calStr.joinToString(separator = " "))


output of above code

button image as form input submit button?

You can also use a second image to give the effect of a button being pressed. Just add the "pressed" button image in the HTML before the input image:

<img src="" id="pressed"/>
<input id="unpressed" type="submit" value=" " style="background:url( no-repeat;border:none;"/>

And use CSS to change the opacity of the "unpressed" image on hover:

#pressed, #unpressed{position:absolute; left:0px;}
#unpressed{opacity: 1; cursor: pointer;}
#unpressed:hover{opacity: 0;}

I use it for the blue "GO" button on this page

Relative imports - ModuleNotFoundError: No module named x

TL;DR: You can't do relative imports from the file you execute since __main__ module is not a part of a package.

Absolute imports - import something available on sys.path

Relative imports - import something relative to the current module, must be a part of a package

If you're running both variants in exactly the same way, one of them should work. Here is an example that should help you understand what's going on. Let's add another file with the overall directory structure like this:


And let's update to see what's going on:

debug = True

    # Trying to find module in the parent package
    from . import config
    del config
except ImportError:
    print('Relative import failed')

    # Trying to find module on sys.path
    import config
except ModuleNotFoundError:
    print('Absolute import failed')
import ryan.test

Let's run first:

$ python ryan/
Relative import failed

Here "test" is the __main__ module and doesn't know anything about belonging to a package. However import config should work, since the ryan folder will be added to sys.path.

Let's run instead:

$ python
Absolute import failed

And here test is inside of the "ryan" package and can perform relative imports. import config fails since implicit relative imports are not allowed in Python 3.

Hope this helped.

P.S.: If you're sticking with Python 3 there is no more need for files.

Adding Git-Bash to the new Windows Terminal

If you want to display an icon and are using a dark theme. Which means the icon provided above doesn't look that great. Then you can find the icon here

C:\Program Files\Git\mingw64\share\git\git-for-windows I copied it into.


and named it git-bash_32px as suggested above.

Control the opacity with CTRL + SHIFT + scrolling.

            "acrylicOpacity" : 0.75,
            "closeOnExit" : true,
            "colorScheme" : "Campbell",
            "commandline" : "\"%PROGRAMFILES%\\git\\usr\\bin\\bash.exe\" -i -l",
            "cursorColor" : "#FFFFFF",
            "cursorShape" : "bar",
            "fontFace" : "Consolas",
            "fontSize" : 10,
            "guid" : "{73225108-7633-47ae-80c1-5d00111ef646}",
            "historySize" : 9001,
            "icon" : "ms-appdata:///roaming/git-bash_32px.ico",
            "name" : "Bash",
            "padding" : "0, 0, 0, 0",
            "snapOnInput" : true,
            "startingDirectory" : "%USERPROFILE%",
            "useAcrylic" : true


this statement

DBMS_OUTPUT.PUT_LINE('a.firstName' || 'a.lastName');

means to print the string as it is.. remove the quotes to get the values to be printed.So the correct syntax is

DBMS_OUTPUT.PUT_LINE(a.firstName || a.lastName);

How can I select rows with most recent timestamp for each key value?

WITH SensorTimes As (
   SELECT sensorID, MAX(timestamp) "LastReading"
   FROM sensorTable
   GROUP BY sensorID
SELECT s.sensorID,s.timestamp,s.sensorField1,s.sensorField2 
FROM sensorTable s
INNER JOIN SensorTimes t on s.sensorID = t.sensorID and s.timestamp = t.LastReading

Redirect echo output in shell script to logfile

You can easily redirect different parts of your shell script to a file (or several files) using sub-shells:

} > file1
} > file2

Tomcat base URL redirection

Name your webapp WAR “ROOT.war” or containing folder “ROOT”

Get public/external IP address?

Expanding on this answer by @suneel ranga:

static System.Net.IPAddress GetPublicIp(string serviceUrl = "")
    return System.Net.IPAddress.Parse(new System.Net.WebClient().DownloadString(serviceUrl));

Where you would use a service with System.Net.WebClient that simply shows the IP address as a string and uses the System.Net.IPAddress object. Here are a few such services*:

* Some services were mentioned in this question and from these answers from superuser site.

Java double.MAX_VALUE?

this states that Account.deposit(Double.MAX_VALUE); it is setting deposit value to MAX value of Double procced for running tests.

How to read a list of files from a folder using PHP?

There is this function scandir():

$dir = 'dir';
$files = scandir($dir, 0);
for($i = 2; $i < count($files); $i++)
    print $files[$i]."<br>";

More here in the manual

How do I force make/GCC to show me the commands?

Depending on your automake version, you can also use this:



Note: I added this answer since V=1 did not work for me.

SyntaxError: missing ) after argument list

How to reproduce this error:

SyntaxError: missing ) after argument list

This code produces the error:

<script type="text/javascript" src="jquery-2.1.0.min.js"></script>
<script type="text/javascript">


If you run this and look at the error output in firebug, you get this error. The empty function passed into 'ready' is not closed. Fix it like this:

<script type="text/javascript" src="jquery-2.1.0.min.js"></script>
<script type="text/javascript">

  });      //<-- notice the right parenthesis and semicolon

And then the Javascript is interpreted correctly.

Last Run Date on a Stored Procedure in SQL Server

Oh, be careful now! All that glitters is NOT gold! All of the “stats” dm views and functions have a problem for this type of thing. They only work against what is in cache and the lifetime of what is in cache can be measure in minutes. If you were to use such a thing to determine which SPs are candidates for being dropped, you could be in for a world of hurt when you delete SPs that were used just minutes ago.

The following excerpts are from Books Online for the given dm views…

sys.dm_exec_procedure_stats Returns aggregate performance statistics for cached stored procedures. The view contains one row per stored procedure, and the lifetime of the row is as long as the stored procedure remains cached. When a stored procedure is removed from the cache, the corresponding row is eliminated from this view.

sys.dm_exec_query_stats The view contains one row per query statement within the cached plan, and the lifetime of the rows are tied to the plan itself. When a plan is removed from the cache, the corresponding rows are eliminated from this view.

Disable button in angular with two conditions?

Declare a variable in component.ts and initialize it to some value

 buttonDisabled: boolean;

  ngOnInit() {
    this.buttonDisabled = false;

Now in .html or in the template, you can put following code:

<button disabled="{{buttonDisabled}}"> Click Me </button>

Now you can enable/disable button by changing value of buttonDisabled variable.

How do I POST a x-www-form-urlencoded request using Fetch?

var details = {
    'userName': '[email protected]',
    'password': 'Password!',
    'grant_type': 'password'

var formBody = [];
for (var property in details) {
  var encodedKey = encodeURIComponent(property);
  var encodedValue = encodeURIComponent(details[property]);
  formBody.push(encodedKey + "=" + encodedValue);
formBody = formBody.join("&");

fetch('' + '/token', {
  method: 'POST',
  headers: {
    'Accept': 'application/json',
    'Content-Type': 'application/x-www-form-urlencoded'
  body: formBody

it is so helpful for me and works without any error

refrence :

How to select top n rows from a datatable/dataview in ASP.NET


Docker error: invalid reference format: repository name must be lowercase

I wish the error message would output the problem string. I was getting this due to a weird copy and paste problem of a "docker run" command. A space-like character was being used before the repo and image name.

How to refresh materialized view in oracle

Run this script to refresh data in materialized view:


How to list all tags along with the full message in git?

git tag -l --format='%(contents)'


git for-each-ref refs/tags/ --format='%(contents)'

will output full annotation message for every tag (including signature if its signed).

  • %(contents:subject) will output only first line
  • %(contents:body) will output annotation without first line and signature (useful text only)
  • %(contents:signature) will output only PGP-signature

See more in man git-for-each-ref “Field names” section.

What is the meaning of 'No bundle URL present' in react-native?

Solution --> npm start then open new Terminal and go to your project path and then hit react-native run-ios it works for me

How to get only the last part of a path in Python?

I was searching for a solution to get the last foldername where the file is located, I just used split two times, to get the right part. It's not the question but google transfered me here.

pathname = "/folderA/folderB/folderC/folderD/"
head, tail = os.path.split(os.path.split(pathname)[0])
print(head + "   "  + tail)

Visual Studio: Relative Assembly References Paths

To expand upon Pavel Minaev's original comment - The GUI for Visual Studio supports relative references with the assumption that your .sln is the root of the relative reference. So if you have a solution C:\myProj\myProj.sln, any references you add in subfolders of C:\myProj\ are automatically added as relative references.

To add a relative reference in a separate directory, such as C:/myReferences/myDLL.dll, do the following:

  1. Add the reference in Visual Studio GUI by right-clicking the project in Solution Explorer and selecting Add Reference...
  2. Find the *.csproj where this reference exist and open it in a text editor
  3. Edit the < HintPath > to be equal to


This now references C:\myReferences\myDLL.dll.

Hope this helps.

How do I capture all of my compiler's output to a file?

In C shell - The ampersand is after the greater-than symbol

make >& filename

Commenting out code blocks in Atom

Also, there are packages:

How can I control Chromedriver open window size?

If you're using the Facebook language binding for php try this:

$driver->manage()->window()->setSize(new WebDriverDimension(1024,768));

How to make tesseract to recognize only numbers, when they are mixed with letters?

If one want to match 0-9

tesseract myimage.png stdout -c tessedit_char_whitelist=0123456789

Or if one almost wants to match 0-9, but with one or more different characters

tesseract myimage.png stdout -c tessedit_char_whitelist=01234ABCDE

Correctly determine if date string is a valid date in that format

You can also Parse the date for month date and year and then you can use the PHP function checkdate() which you can read about here:

You can also try this one:


if (preg_match("/^[0-9]{4}-(0[1-9]|1[0-2])-(0[1-9]|[1-2][0-9]|3[0-1])$/",$date))
        echo 'Date is valid';
        echo 'Date is invalid';

Cloning git repo causes error - Host key verification failed. fatal: The remote end hung up unexpectedly

Resolved the issue... you need to add the ssh public key to your github account.

  1. Verify that the ssh keys have been setup correctly.
    1. Run ssh-keygen
    2. Enter the password (keep the default path - ~/.ssh/id_rsa)
  2. Add the public key (~/.ssh/ to github account
  3. Try git clone. It works!

Initial status (public key not added to git hub account)

foo@bn18-251:~$ rm -rf test
foo@bn18-251:~$ ls
foo@bn18-251:~$ git clone [email protected]:devendra-d-chavan/test.git
Cloning into 'test'...
Permission denied (publickey).
fatal: The remote end hung up unexpectedly

Now, add the public key ~/.ssh/ to the github account (I used cat ~/.ssh/

foo@bn18-251:~$ ssh-keygen 
Generating public/private rsa key pair.
Enter file in which to save the key (/home/foo/.ssh/id_rsa): 
Created directory '/home/foo/.ssh'.
Enter passphrase (empty for no passphrase): 
Enter same passphrase again: 
Your identification has been saved in /home/foo/.ssh/id_rsa.
Your public key has been saved in /home/foo/.ssh/
The key fingerprint is:
The key's randomart image is:
+--[ RSA 2048]----+
foo@bn18-251:~$ cat ./.ssh/ 
foo@bn18-251:~$ git clone [email protected]:devendra-d-chavan/test.git
Cloning into 'test'...
The authenticity of host ' (' can't be established.
RSA key fingerprint is 16:27:ac:a5:76:28:2d:36:63:1b:56:4d:eb:df:a6:48.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added ',' (RSA) to the list of known hosts.
Enter passphrase for key '/home/foo/.ssh/id_rsa': 
warning: You appear to have cloned an empty repository.
foo@bn18-251:~$ ls
foo@bn18-251:~/test$ git status
# On branch master
# Initial commit
nothing to commit (create/copy files and use "git add" to track)

How do I remove lines between ListViews on Android?

To remove the separator between items in the same ListView, here is the solution:

getListView().setDividerHeight(0); # ListView

Or, if you want to do it in XML:


How can I use external JARs in an Android project?

If using Android Studio, do the following (I've copied and modified @Vinayak Bs answer):

  1. Select the Project view in the Project sideview (instead of Packages or Android)
  2. Create a folder called libs in your project's root folder
  3. Copy your JAR files to the libs folder
  4. The sideview will be updated and the JAR files will show up in your project
  5. Now right click on each JAR file you want to import and then select "Add as Library...", which will include it in your project
  6. After that, all you need to do is reference the new classes in your code, eg. import javax.mail.*

Why does comparing strings using either '==' or 'is' sometimes produce a different result?

is is identity testing, == is equality testing. what happens in your code would be emulated in the interpreter like this:

>>> a = 'pub'
>>> b = ''.join(['p', 'u', 'b'])
>>> a == b
>>> a is b

so, no wonder they're not the same, right?

In other words: a is b is the equivalent of id(a) == id(b)

How do I concatenate or merge arrays in Swift?

Similarly, with dictionaries of arrays one can:

var dict1 = [String:[Int]]()
var dict2 = [String:[Int]]()
dict1["key"] = [1,2,3]
dict2["key"] = [4,5,6]
dict1["key"] = dict1["key"]! + dict2["key"]!

and you can iterate over dict1 and add dict2 if the "key" matches

Reading e-mails from Outlook with Python through MAPI

I have created my own iterator to iterate over Outlook objects via python. The issue is that python tries to iterates starting with Index[0], but outlook expects for first item Index[1]... To make it more Ruby simple, there is below a helper class Oli with following methods:

.items() - yields a tuple(index, Item)...

.prop() - helping to introspect outlook object exposing available properties (methods and attributes)

from win32com.client import constants
from win32com.client.gencache import EnsureDispatch as Dispatch

outlook = Dispatch("Outlook.Application")
mapi = outlook.GetNamespace("MAPI")

class Oli():
    def __init__(self, outlook_object):
        self._obj = outlook_object

    def items(self):
        array_size = self._obj.Count
        for item_index in xrange(1,array_size+1):
            yield (item_index, self._obj[item_index])

    def prop(self):
        return sorted( self._obj._prop_map_get_.keys() )

for inx, folder in Oli(mapi.Folders).items():
    # iterate all Outlook folders (top level)
    print "-"*70
    print folder.Name

    for inx,subfolder in Oli(folder.Folders).items():
        print "(%i)" % inx, subfolder.Name,"=> ", subfolder

What is the default access modifier in Java?

The default modifier is package. Only code in the same package will be able to invoke this constructor.

Is it possible to use argsort in descending order?

With your example:

avgDists = np.array([1, 8, 6, 9, 4])

Obtain indexes of n maximal values:

ids = np.argpartition(avgDists, -n)[-n:]

Sort them in descending order:

ids = ids[np.argsort(avgDists[ids])[::-1]]

Obtain results (for n=4):

>>> avgDists[ids]
array([9, 8, 6, 4])

Floating point inaccuracy examples

There are basically two major pitfalls people stumble in with floating-point numbers.

  1. The problem of scale. Each FP number has an exponent which determines the overall “scale” of the number so you can represent either really small values or really larges ones, though the number of digits you can devote for that is limited. Adding two numbers of different scale will sometimes result in the smaller one being “eaten” since there is no way to fit it into the larger scale.

    PS> $a = 1; $b = 0.0000000000000000000000001
    PS> Write-Host a=$a b=$b
    a=1 b=1E-25
    PS> $a + $b

    As an analogy for this case you could picture a large swimming pool and a teaspoon of water. Both are of very different sizes, but individually you can easily grasp how much they roughly are. Pouring the teaspoon into the swimming pool, however, will leave you still with roughly a swimming pool full of water.

    (If the people learning this have trouble with exponential notation, one can also use the values 1 and 100000000000000000000 or so.)

  2. Then there is the problem of binary vs. decimal representation. A number like 0.1 can't be represented exactly with a limited amount of binary digits. Some languages mask this, though:

    PS> "{0:N50}" -f 0.1

    But you can “amplify” the representation error by repeatedly adding the numbers together:

    PS> $sum = 0; for ($i = 0; $i -lt 100; $i++) { $sum += 0.1 }; $sum

    I can't think of a nice analogy to properly explain this, though. It's basically the same problem why you can represent 1/3 only approximately in decimal because to get the exact value you need to repeat the 3 indefinitely at the end of the decimal fraction.

    Similarly, binary fractions are good for representing halves, quarters, eighths, etc. but things like a tenth will yield an infinitely repeating stream of binary digits.

  3. Then there is another problem, though most people don't stumble into that, unless they're doing huge amounts of numerical stuff. But then, those already know about the problem. Since many floating-point numbers are merely approximations of the exact value this means that for a given approximation f of a real number r there can be infinitely many more real numbers r1, r2, ... which map to exactly the same approximation. Those numbers lie in a certain interval. Let's say that rmin is the minimum possible value of r that results in f and rmax the maximum possible value of r for which this holds, then you got an interval [rmin, rmax] where any number in that interval can be your actual number r.

    Now, if you perform calculations on that number—adding, subtracting, multiplying, etc.—you lose precision. Every number is just an approximation, therefore you're actually performing calculations with intervals. The result is an interval too and the approximation error only ever gets larger, thereby widening the interval. You may get back a single number from that calculation. But that's merely one number from the interval of possible results, taking into account precision of your original operands and the precision loss due to the calculation.

    That sort of thing is called Interval arithmetic and at least for me it was part of our math course at the university.

CSS background-image-opacity?

Try this trick .. use css shadow with (inset) option and make the deep 200px for example


box-shadow: inset 0px 0px 277px 3px #4c3f37;


Also for all browsers:

-moz-box-shadow: inset 0px 0px 47px 3px #4c3f37;
-webkit-box-shadow: inset 0px 0px 47px 3px #4c3f37;
box-shadow: inset 0px 0px 277px 3px #4c3f37;

and increase number to make fill your box :)


How can I simulate a click to an anchor tag?

Quoted from

The click method is intended to be used with INPUT elements of type button, checkbox, radio, reset or submit. Gecko does not implement the click method on other elements that might be expected to respond to mouse–clicks such as links (A elements), nor will it necessarily fire the click event of other elements.

Non–Gecko DOMs may behave differently.

Unfortunately it sounds like you have already discovered the best solution to your problem.

As a side note, I agree that your solution seems less than ideal, but if you encapsulate the functionality inside a method (much like JQuery would do) it is not so bad.

Finding the max value of an attribute in an array of objects

Here is the shortest solution (One Liner) ES6:

Math.max( => o.y));

Show space, tab, CRLF characters in editor of Visual Studio

Display white space characters

Menu: You can toggle the visibility of the white space characters from the menu: Edit > Advanced > View White Space.

Button: If you want to add the button to a toolbar, it is called Toggle Visual Space in the command category "Edit".
The actual command name is: Edit.ViewWhiteSpace.

Keyboard Shortcut: In Visual Studio 2015, 2017 and 2019 the default keyboard shortcut still is CTRL+R, CTRL+W
Type one after the other.
All default shortcuts

End-of-line characters

Extension: There is a minimal extension adding the displaying of end-of-line characters (LF and CR) to the visual white space mode, as you would expect. Additionally it supplies buttons and short-cuts to modify all line-endings in a document, or a selection.
VisualStudio gallery: End of the Line

Note: Since Visual Studio 2017 there is no option in the File-menu called Advanced Save Options. Changing the encoding and line-endings for a file can be done using Save File As ... and clicking the down-arrow on the right side of the save-button. This shows the option Save with Encoding. You'll be asked permission to overwrite the current file.

How to use FormData in react-native?

Usage of formdata in react-native

I have used react-native-image-picker to select photo. In my case after choosing the photp from mobile. I'm storing it's info in component state. After, I'm sending POST request using fetch like below

const profile_pic = {
  name: this.state.formData.profile_pic.fileName,
  type: this.state.formData.profile_pic.type,
  path: this.state.formData.profile_pic.path,
  uri: this.state.formData.profile_pic.uri,
const formData = new FormData()
formData.append('first_name', this.state.formData.first_name);
formData.append('last_name', this.state.formData.last_name);
formData.append('profile_pic', profile_pic);
const Token = 'secret'

fetch('', {
    method: "POST",
    headers: {
      Accept: "application/json",
      "Content-Type": "multipart/form-data",
      Authorization: `Token ${Token}`
    body: formData
  .then(response => console.log(response.json()))

For div to extend full height

This might be of some help:

A relevant quote:

Most attempts to accomplish this were made by assigning the property and value: div{height:100%} - this alone will not work. The reason is that without a parent defined height, the div{height:100%;} has nothing to factor 100% percent of, and will default to a value of div{height:auto;} - auto is an "as needed value" which is governed by the actual content, so that the div{height:100%} will a=only extend as far as the content demands.

The solution to the problem is found by assigning a height value to the parent container, in this case, the body element. Writing your body stlye to include height 100% supplies the needed value.

html, body { 

How to run a command as a specific user in an init script?

For systemd style init scripts it's really easy. You just add a User= in the [Service] section.

Here is an init script I use for qbittorrent-nox on CentOS 7:

Description=qbittorrent torrent server



Limit length of characters in a regular expression?

If you want to restrict valid input to integer values between 1 and 100, this will do it:



  1. ^ = start of input
  2. () = multiple options to match
  3. First argument [1-9] - matches any entries between 1 and 9
  4. | = OR argument separator
  5. Second Argument [1-9][0-9] - matches entries between 10 and 99
  6. Last Argument 100 - Self explanatory - matches entries of 100

This WILL NOT ACCEPT: 1. Zero - 0 2. Any integer preceded with a zero - 01, 021, 001 3. Any integer greater than 100

Hope this helps!


In Java, how can I determine if a char array contains a particular character?

You can iterate through the array or you can convert it to a String and use indexOf.

if (new String(charArray).indexOf('q') < 0) {

Creating a new String is a bit wasteful, but it's probably the tersest code. You can also write a method to imitate the effect without incurring the overhead.

You don't have write permissions for the /Library/Ruby/Gems/2.3.0 directory. (mac user)

I have faced same issue after install macOS Catalina. I had try below command and its working.

sudo gem update

When to favor ng-if vs. ng-show/ng-hide?

Depends on your use case but to summarise the difference:

  1. ng-if will remove elements from DOM. This means that all your handlers or anything else attached to those elements will be lost. For example, if you bound a click handler to one of child elements, when ng-if evaluates to false, that element will be removed from DOM and your click handler will not work any more, even after ng-if later evaluates to true and displays the element. You will need to reattach the handler.
  2. ng-show/ng-hide does not remove the elements from DOM. It uses CSS styles to hide/show elements (note: you might need to add your own classes). This way your handlers that were attached to children will not be lost.
  3. ng-if creates a child scope while ng-show/ng-hide does not

Elements that are not in the DOM have less performance impact and your web app might appear to be faster when using ng-if compared to ng-show/ng-hide. In my experience, the difference is negligible. Animations are possible when using both ng-show/ng-hide and ng-if, with examples for both in the Angular documentation.

Ultimately, the question you need to answer is whether you can remove element from DOM or not?

How to format a Date in MM/dd/yyyy HH:mm:ss format in JavaScript?

var d = new Date();

var curr_date = d.getDate();

var curr_month = d.getMonth();

var curr_year = d.getFullYear();

document.write(curr_date + "-" + curr_month + "-" + curr_year);

using this you can format date.

you can change the appearance in the way you want then

for more info you can visit here

iOS start Background Thread

If you use performSelectorInBackground:withObject: to spawn a new thread, then the performed selector is responsible for setting up the new thread's autorelease pool, run loop and other configuration details – see "Using NSObject to Spawn a Thread" in Apple's Threading Programming Guide.

You'd probably be better off using Grand Central Dispatch, though:

dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
    [self getResultSetFromDB:docids];

GCD is a newer technology, and is more efficient in terms of memory overhead and lines of code.

Updated with a hat tip to Chris Nolet, who suggested a change that makes the above code simpler and keeps up with Apple's latest GCD code examples.

Best practice: PHP Magic Methods __set and __get

Second code example is much more proper way to do this because you are taking full control of data which are given to class. There are cases in which the __set and __get are useful but not in this case.

Best way to generate xml?

ElementTree is a good module for reading xml and writing too e.g.

from xml.etree.ElementTree import Element, SubElement, tostring

root = Element('root')
child = SubElement(root, "child")
child.text = "I am a child"



<root><child>I am a child</child></root>

See this tutorial for more details and how to pretty print.

Alternatively if your XML is simple, do not underestimate the power of string formatting :)

xmlTemplate = """<root>

data = {'name':'anurag', 'address':'Pune, india'}
print xmlTemplate%data


        <address>Pune, india</address>

You can use string.Template or some template engine too, for complex formatting.

How to set Navigation Drawer to be opened from right to left



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

    <include layout="@layout/app_bar_root"
        android:layout_height="match_parent" />

        app:menu="@menu/activity_root_drawer" />


protected void onCreate(Bundle savedInstanceState) {
toolbar = (Toolbar) findViewById(;

drawer = (DrawerLayout) findViewById(;
ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
            this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);

toolbar.setNavigationOnClickListener(new View.OnClickListener() {

        public void onClick(View v) {
            if (drawer.isDrawerOpen(Gravity.RIGHT)) {
            } else {

error LNK2019: unresolved external symbol _WinMain@16 referenced in function ___tmainCRTStartup

Your tried to turn that source file into an executable, which obviously isn't possible, because the mandatory entry point, the main function, isn't defined. Add a file main.cpp and define a main function. If you're working on the commandline (which I doubt), you can add /c to only compile and not link. This will produce an object file only, which needs to be linked into either a static or shared lib or an application (in which case you'll need an oject file with main defined).

_WinMain is Microsoft's name for main when linking.

Also: you're not running the code yet, you are compiling (and linking) it. C++ is not an interpreted language.

Get changes from master into branch in Git

You have a couple options. git rebase master aqonto the branch which will keep the commit names, but DO NOT REBASE if this is a remote branch. You can git merge master aq if you don't care about keeping the commit names. If you want to keep the commit names and it is a remote branch git cherry-pick <commit hash> the commits onto your branch.

How to find all duplicate from a List<string>?

In .NET framework 3.5 and above you can use Enumerable.GroupBy which returns an enumerable of enumerables of duplicate keys, and then filter out any of the enumerables that have a Count of <=1, then select their keys to get back down to a single enumerable:

var duplicateKeys = list.GroupBy(x => x)
                        .Where(group => group.Count() > 1)
                        .Select(group => group.Key);

How do I increment a DOS variable in a FOR /F loop?

I would like to add that in case in you create local variables within the loop, they need to be expanded using the bang(!) notation as well. Extending the example at above, if we want to create counter-based output filenames

set TEXT_T="myfile.txt"

set /a c=1


FOR /F "tokens=1 usebackq" %%i in (%TEXT_T%) do (
    set /a c=c+1
    set OUTPUT_FILE_NAME=output_!c!.txt
    echo Output file is !OUTPUT_FILE_NAME!
    echo %%i, !c!


React native ERROR Packager can't listen on port 8081

Try to run in another port like 3131. Run the command:

react-native run-android --port=3131

Unsafe JavaScript attempt to access frame with URL

I found that using the XFBML version of the Facebook like button instead of the HTML5 version fixed this problem. Add the below code where you want the button to appear:

<div id="fb-root"></div>
<script>(function (d, s, id) {
    var js, fjs = d.getElementsByTagName(s)[0];
    if (d.getElementById(id)) return;
    js = d.createElement(s); = id;
    js.src = "//";
    fjs.parentNode.insertBefore(js, fjs);
}(document, 'script', 'facebook-jssdk'));</script>

<fb:like send="true" layout="button_count" width="50" show_faces="false" font="arial"></fb:like>

Then add this to your HTML tag:


Setting the value of checkbox to true or false with jQuery

Use $('#id-of-the-checkbox').prop('checked', true_or_false);

In case you are using an ancient jQuery version, you'll need to use .attr('checked', 'checked') to check and .removeAttr('checked') to uncheck.

Delimiter must not be alphanumeric or backslash and preg_match

You need a delimiter for your pattern. It should be added at the start and end of the pattern like so:

$pattern = "/My name is '(.*)' and im fine/";  // With / as a delimeter 

Get value of div content using jquery

You can get div content using .text() in jquery

var divContent = $('#field-function_purpose').text();


Increasing the JVM maximum heap size for memory intensive applications

When you are using JVM in 32-bit mode, the maximum heap size that can be allocated is 1280 MB. So, if you want to go beyond that, you need to invoke JVM in 64-mode.

You can use following:

$ java -d64 -Xms512m -Xmx4g HelloWorld


  • -d64: Will enable 64-bit JVM
  • -Xms512m: Will set initial heap size as 512 MB
  • -Xmx4g: Will set maximum heap size as 4 GB

You can tune in -Xms and -Xmx as per you requirements (YMMV)

A very good resource on JVM performance tuning, which might want to look into:

How do I use regular expressions in bash scripts?

It was changed between 3.1 and 3.2:

This is a terse description of the new features added to bash-3.2 since the release of bash-3.1.

Quoting the string argument to the [[ command's =~ operator now forces string matching, as with the other pattern-matching operators.

So use it without the quotes thus:

if [[ $i =~ 200[78] ]] ; then
    echo "OK"
    echo "not OK"

Column order manipulation using col-lg-push and col-lg-pull in Twitter Bootstrap 3

Pull "pulls" the div towards the left of the browser and and Push "pushes" the div away from left of browser.

Like: enter image description here

So basically in a 3 column layout of any web page the "Main Body" appears at the "Center" and in "Mobile" view the "Main Body" appears at the "Top" of the page. This is mostly desired by everyone with 3 column layout.

<div class="container">
    <div class="row">
        <div id="content" class="col-lg-4 col-lg-push-4 col-sm-12">
        <h2>This is Content</h2>
        <p>orem Ipsum ...</p>

        <div id="sidebar-left" class="col-lg-4  col-sm-6 col-lg-pull-4">
        <h2>This is Left Sidebar</h2>
        <p>orem Ipsum...</p>

        <div id="sidebar-right" class="col-lg-4 col-sm-6">
        <h2>This is Right Sidebar</h2>
        <p>orem Ipsum.... </p>

You can view it here:

Hope it helps

C# windows application Event: CLR20r3 on application start

I encountered the same problem when I built an application on a Windows 7 box that had previously been maintained on an XP machine.

The program ran fine when built for Debug, but failed with this error when built for Release. I found the answer on the project's Properties page. Go to the "Build" tab and try changing the Platform Target from "Any CPU" to "x86".

What does -1 mean in numpy reshape?

It is fairly easy to understand. The "-1" stands for "unknown dimension" which can should be infered from another dimension. In this case, if you set your matrix like this:

a = numpy.matrix([[1, 2, 3, 4], [5, 6, 7, 8]])

Modify your matrix like this:

b = numpy.reshape(a, -1)

It will call some deafult operations to the matrix a, which will return a 1-d numpy array/martrix.

However, I don't think it is a good idea to use code like this. Why not try:

b = a.reshape(1,-1)

It will give you the same result and it's more clear for readers to understand: Set b as another shape of a. For a, we don't how much columns it should have(set it to -1!), but we want a 1-dimension array(set the first parameter to 1!).

How can I escape double quotes in XML attributes values?

From the XML specification:

To allow attribute values to contain both single and double quotes, the apostrophe or single-quote character (') may be represented as "&apos;", and the double-quote character (") as "&quot;".

how to use math.pi in java

Here is usage of Math.PI to find circumference of circle and Area First we take Radius as a string in Message Box and convert it into integer

public class circle {

    public static void main(String[] args) {
        // TODO code application logic here

        String rad;

        float radius,area,circum;

       rad = JOptionPane.showInputDialog("Enter the Radius of circle:");

        radius = Integer.parseInt(rad);
        area = (float) (Math.PI*radius*radius);
        circum = (float) (2*Math.PI*radius);

        JOptionPane.showMessageDialog(null, "Area: " + area,"AREA",JOptionPane.INFORMATION_MESSAGE);
        JOptionPane.showMessageDialog(null, "circumference: " + circum, "Circumfernce",JOptionPane.INFORMATION_MESSAGE);


How to handle a single quote in Oracle SQL

Use two single-quotes



Alternatively, use the new (10g+) quoting method:



"The transaction log for database is full due to 'LOG_BACKUP'" in a shared host

I got the same error but from a backend job (SSIS job). Upon checking the database's Log file growth setting, the log file was limited growth of 1GB. So what happened is when the job ran and it asked SQL server to allocate more log space, but the growth limit of the log declined caused the job to failed. I modified the log growth and set it to grow by 50MB and Unlimited Growth and the error went away.

Parse JSON file using GSON

I'm using gson 2.2.3

public class Main {

 * @param args
 * @throws IOException 
public static void main(String[] args) throws IOException {

    JsonReader jsonReader = new JsonReader(new FileReader("jsonFile.json"));


    while (jsonReader.hasNext()) {

    String name = jsonReader.nextName();
        if (name.equals("descriptor")) {




public static void readApp(JsonReader jsonReader) throws IOException{
     while (jsonReader.hasNext()) {
         String name = jsonReader.nextName();
         if (name.contains("app")){
             while (jsonReader.hasNext()) {
                 String n = jsonReader.nextName();
                 if (n.equals("name")){
                 if (n.equals("age")){
                 if (n.equals("messages")){
                     while  (jsonReader.hasNext()) {


How to build minified and uncompressed bundle with webpack?

You can run webpack twice with different arguments:

$ webpack --minimize

then check command line arguments in webpack.config.js:

var path = require('path'),
  webpack = require('webpack'),
  minimize = process.argv.indexOf('--minimize') !== -1,
  plugins = [];

if (minimize) {
  plugins.push(new webpack.optimize.UglifyJsPlugin());


example webpack.config.js

How to get selected value of a dropdown menu in ReactJS

It is as simple as that. You just need to use "value" attributes instead of "defaultValue" or you can keep both if a pre-selected feature is there.

const [currentValue, setCurrentValue] = useState(2);
<select id = "dropdown" value={currentValue} defaultValue={currentValue}>
     <option value="N/A">N/A</option>
     <option value="1">1</option>
     <option value="2">2</option>
     <option value="3">3</option>
     <option value="4">4</option>

setTimeut(()=> {
}, 4000);

In this case, after 4 secs the dropdown will be auto-selected with option 4.

How to get an array of specific "key" in multidimensional array without looping

PHP 5.5+

Starting PHP5.5+ you have array_column() available to you, which makes all of the below obsolete.

PHP 5.3+

$ids = array_map(function ($ar) {return $ar['id'];}, $users);

Solution by @phihag will work flawlessly in PHP starting from PHP 5.3.0, if you need support before that, you will need to copy that wp_list_pluck.

PHP < 5.3

Wordpress 3.1+

In Wordpress there is a function called wp_list_pluck If you're using Wordpress that solves your problem.

PHP < 5.3

If you're not using Wordpress, since the code is open source you can copy paste the code in your project (and rename the function to something you prefer, like array_pick). View source here

convert epoch time to date

EDIT: Okay, so you don't want your local time (which isn't Australia) to contribute to the result, but instead the Australian time zone. Your existing code should be absolutely fine then, although Sydney is currently UTC+11, not UTC+10.. Short but complete test app:

import java.util.*;
import java.text.*;

public class Test {
    public static void main(String[] args) throws InterruptedException {
        Date date = new Date(1318386508000L);
        DateFormat format = new SimpleDateFormat("dd/MM/yyyy HH:mm:ss");
        String formatted = format.format(date);
        formatted = format.format(date);


12/10/2011 02:28:28
12/10/2011 13:28:28

I would also suggest you start using Joda Time which is simply a much nicer date/time API...

EDIT: Note that if your system doesn't know about the Australia/Sydney time zone, it would show UTC. For example, if I change the code about to use TimeZone.getTimeZone("blah/blah") it will show the UTC value twice. I suggest you print TimeZone.getTimeZone("Australia/Sydney").getDisplayName() and see what it says... and check your code for typos too :)

Delete an element from a dictionary

pop mutates the dictionary.

 >>> lol = {"hello": "gdbye"}
 >>> lol.pop("hello")
 >>> lol

If you want to keep the original you could just copy it.

AssertionError: View function mapping is overwriting an existing endpoint function: main

I would just like to add to this a more 'template' type solution.

def func_name(f):
    def wrap(*args, **kwargs):
        if condition:
            whatever you want
        return f(*args, **kwargs)
    wrap.__name__ = f.__name__
    return wrap

would just like to add a really interesting article "Demystifying Decorators" I found recently:

Eclipse will not open due to environment variables

Ok...Ok... Don't worry i am also ruined by this error and fatal and when i got it i was so serious even i was not giving an attention to other work, but i got it, Simply first of all copy this code and paste in your system variable Under path ...

C:\Program Files;C:\Winnt;C:\Winnt\System32;C:\Program Files\Java\jre6\bin\javaw.exe

Now copy the "jre" folder from your path like i have have "jre" under this path

            C:\Program Files\Java

and paste it in your eclipse folder means where your eclipse.exe file is placed. like i have my eclipse set up in this location

    F:\Softwares\LANGUAGES SOFTEARE\Android Setup\eclipse

So inside the eclipse Folder paste the "jre" FOLDER . If you have "jre6" then rename it as "jre"....and run your eclipse you will got the solution...



If the problem could't solve with the above steps, then follow these steps

  1. Copy the folder "jre" from your Java path like C:\Program Files\Java\jre6* etc, and paste it in your eclipse directory(Where is your eclipse available)
  2. Go to eclipse.ini file , open it up.
  3. Change the directory of your javaw.exe file like

-vmF:\Softwares\LANGUAGES SOFTEARE\Android Setup\eclipse Indigo version 32 Bit\jre\bin/javaw.exe

Now this time when you will start eclipse it will search for javaw.exe, so it will search the path in the eclipse.ini, as it is now in the same folder so, it will start the javaw.exe and it will start working.

If You still have any query you can ask it again, just go on my profile and find out my email id. because i love stack overflow forum, and it made me a programmer.*

How do I address unchecked cast warnings?

Unfortunately, there are no great options here. Remember, the goal of all of this is to preserve type safety. "Java Generics" offers a solution for dealing with non-genericized legacy libraries, and there is one in particular called the "empty loop technique" in section 8.2. Basically, make the unsafe cast, and suppress the warning. Then loop through the map like this:

Map<String, Number> map = getMap();
for (String s : map.keySet());
for (Number n : map.values());

If an unexpected type is encountered, you will get a runtime ClassCastException, but at least it will happen close to the source of the problem.

How do I pass parameters to a jar file at the time of execution?

You can do it with something like this, so if no arguments are specified it will continue anyway:

public static void main(String[] args) {
    try {
        String one = args[0];
        String two = args[1];
    catch (ArrayIndexOutOfBoundsException e){
        System.out.println("ArrayIndexOutOfBoundsException caught");
    finally {


And then launch the application:

java -jar myapp.jar arg1 arg2

Checking if a key exists in a JavaScript object?

The easiest way to check is

"key" in object

for example:

var obj = {
  a: 1,
  b: 2,
"a" in obj // true
"c" in obj // false

Return value as true implies that key exists in the object.

IndexOf function in T-SQL

One very small nit to pick:

The RFC for email addresses allows the first part to include an "@" sign if it is quoted. Example:


This is quite uncommon, but could happen. Theoretically, you should split on the last "@" symbol, not the first:

SELECT LEN(EmailField) - CHARINDEX('@', REVERSE(EmailField)) + 1

More information:

Android Emulator: Installation error: INSTALL_FAILED_VERSION_DOWNGRADE


All Android apps have a package name. The package name uniquely identifies the app on the device. If same packageName as app that's already installed on the device then this error Showing .

  1. You can uninstall the application from your device first and then install the fresh one .
  2. You could simply increase the number by one each time a new version is released.

Illegal access: this web application instance has been stopped already

In short: this happens likely when you are hot-deploying webapps. For instance, your ide+development server hot-deploys a war again. Threads, that have been created previously are still running. But meanwhile their classloader/context is invalid and faces the IllegalAccessException / IllegalStateException becouse its orgininating webapp (the former runtime-environment) has been redeployed.

So, as states here, a restart does not permanently resolve this issue. Instead, it is better to find/implement a managed Thread Pool, like this to handle the termination of threads appropriately. In JavaEE you will use these ManagedThreadExeuctorServices. A similar opinion and reference here.

Examples for this are the EvictorThread of Apache Commons Pool, that "cleans" pooled instances according to the pool's configuration (max idle etc.).

.substring error: "is not a function"

document.location is an object, not a string. It returns (by default) the full path, but it actually holds more info than that.

Shortcut for solution: document.location.toString().substring(2,3);

Or use document.location.href or window.location.href

How can I copy a file from a remote server to using Putty in Windows?

One of the putty tools is pscp.exe; it will allow you to copy files from your remote host.

SQL: Combine Select count(*) from multiple tables

  (select count(*) from foo) as foo
, (select count(*) from bar) as bar
, ...

Multiple glibc libraries on a single host

I am not sure that the question is still relevant, but there is another way of fixing the problem: Docker. One can install an almost empty container of the Source Distribution (The Distribution used for development) and copy the files into the Container. That way You do not need to create the filesystem needed for chroot.

IntelliJ - Convert a Java project/module into a Maven project/module

This fixed it for me: Open maven projects tab on the right. Add the pom if not yet present, then click refresh on the top left of the tab.

How to rename with prefix/suffix?

Bulk rename files bash script

# USAGE EXAMPLE: cd PHOTOS; /home/Desktop/ 2016_
# VERSION: 2016.03.05.
# COPYRIGHT: Harkály Gergo | mangoRDI ( 

# check isset INITNUMBER argument, if not, set 1 | INITNUMBER is the first number after renaming
if [ -z "$2" ]
    then i=1;

# counts the files to set leading zeros before number | max 1000 files
count=$(ls -l * | wc -l)
if [ $count -lt 10 ]
    then zeros=1;
    if [ $count -lt 100 ]
        then zeros=2;

# rename script
for file in *
    mv $file $1_$(printf %0"$zeros"d.%s ${i%.*} ${file##*.})
    let i="$i+1"

Hiding user input on terminal in Linux script

Get Username and password

Make it more clear to read but put it on a better position over the screen

unset username
prompt="  Enter Username:"
while IFS= read -p "$prompt" -r -s -n 1 char
    if [[ $char == $'\0' ]]; then
    elif [ $char == $'\x08' ] && [ $counter -gt 0 ]; then
        prompt=$'\b \b'
    elif [ $char == $'\x08' ] && [ $counter -lt 1 ]; then
unset password
prompt="  Enter Password:"
while IFS= read -p "$prompt" -r -s -n 1 char
    if [[ $char == $'\0' ]]; then
    elif [ $char == $'\x08' ] && [ $counter -gt 0 ]; then
        prompt=$'\b \b'
    elif [ $char == $'\x08' ] && [ $counter -lt 1 ]; then
        prompt="  Enter Password:"

git submodule tracking latest

Edit (2020.12.28): GitHub change default master branch to main branch since October 2020. See

Update March 2013

Git 1.8.2 added the possibility to track branches.

"git submodule" started learning a new mode to integrate with the tip of the remote branch (as opposed to integrating with the commit recorded in the superproject's gitlink).

# add submodule to track master branch
git submodule add -b master [URL to Git repo];

# update your submodule
git submodule update --remote 

If you had a submodule already present you now wish would track a branch, see "how to make an existing submodule track a branch".

Also see Vogella's tutorial on submodules for general information on submodules.


git submodule add -b . [URL to Git repo];

See git submodule man page:

A special value of . is used to indicate that the name of the branch in the submodule should be the same name as the current branch in the current repository.

See commit b928922727d6691a3bdc28160f93f25712c565f6:

submodule add: If --branch is given, record it in .gitmodules

This allows you to easily record a submodule.<name>.branch option in .gitmodules when you add a new submodule. With this patch,

$ git submodule add -b <branch> <repository> [<path>]
$ git config -f .gitmodules submodule.<path>.branch <branch>

reduces to

$ git submodule add -b <branch> <repository> [<path>]

This means that future calls to

$ git submodule update --remote ...

will get updates from the same branch that you used to initialize the submodule, which is usually what you want.

Signed-off-by: W. Trevor King [email protected]

Original answer (February 2012):

A submodule is a single commit referenced by a parent repo.
Since it is a Git repo on its own, the "history of all commits" is accessible through a git log within that submodule.

So for a parent to track automatically the latest commit of a given branch of a submodule, it would need to:

  • cd in the submodule
  • git fetch/pull to make sure it has the latest commits on the right branch
  • cd back in the parent repo
  • add and commit in order to record the new commit of the submodule.

gitslave (that you already looked at) seems to be the best fit, including for the commit operation.

It is a little annoying to make changes to the submodule due to the requirement to check out onto the correct submodule branch, make the change, commit, and then go into the superproject and commit the commit (or at least record the new location of the submodule).

Other alternatives are detailed here.

Autowiring fails: Not an managed Type

After encountering this issue and tried different method of adding the entity packaname name to EntityScan, ComponentScan etc, none of it worked.

Added the package to packageScan config in the EntityManagerFactory of the repository config. The below code gives the code based configuration as opposed to XML based ones answered above.

@Bean(name = "entityManagerFactory")
public EntityManagerFactory entityManagerFactory() {
    LocalContainerEntityManagerFactoryBean emf = new LocalContainerEntityManagerFactoryBean();
    return emf.getObject();

How to tag docker image with docker-compose

It seems the docs/tool have been updated and you can now add the image tag to your script. This was successful for me.


version: '2'
      context: ../..
      dockerfile: app/Docker/Dockerfile.release

Responsive Images with CSS

.erb-image-wrapper img{
    max-width:100% !important;

Worked for me.
Thanks for MrMisterMan for his assistance.

Unzip All Files In A Directory

The following bash script extracts all zip files in the current directory into new dirs with the filename of the zip file, i.e.:

The following files: 

Will be extracted to:


Shell script:

for zip in *.zip
  dirname=`echo $zip | sed 's/\.zip$//'`
  if mkdir "$dirname"
    if cd "$dirname"
      unzip ../"$zip"
      cd ..
      # rm -f $zip # Uncomment to delete the original zip file
      echo "Could not unpack $zip - cd failed"
    echo "Could not unpack $zip - mkdir failed"

Is it possible to play music during calls so that the partner can hear it ? Android

No, It is not possible. But if you want to dig it more, then you can visit Using Android phone as GSM Gateway for VoIP where author has concluded that

It's not possible to use Android as a GSM Gateway in its current form. Even after flashing custom ROM because they also depends on proprietary RIL (Radio Interface Layer) firmwares. Hurdles 1 and 2 (API limitation) can be removed because the source code is available for the open source community to make it possible. However, the hurdle 3 (proprietary RIL) is dependent on the hardware vendors. Hardware vendors do not usually make their device drivers code available.

Correct way to initialize empty slice

The two alternative you gave are semantically identical, but using make([]int, 0) will result in an internal call to runtime.makeslice (Go 1.14).

You also have the option to leave it with a nil value:

var myslice []int

As written in the blog:

a nil slice is functionally equivalent to a zero-length slice, even though it points to nothing. It has length zero and can be appended to, with allocation.

A nil slice will however json.Marshal() into "null" whereas an empty slice will marshal into "[]", as pointed out by @farwayer.

None of the above options will cause any allocation, as pointed out by @ArmanOrdookhani.

How to solve 'Redirect has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header'?

$.get('' + c1v + '/' + c1b, function (data) { 
  // some code...

Just put "https" .

float:left; vs display:inline; vs display:inline-block; vs display:table-cell;

For the record only, to add to Spudley's answer, there is also the possibility to use position: absolute and margins if you know the column widths.

For me, the main issue when chossing a method is whether you need the columns to fill the whole height (equal heights), where table-cell is the easiest method (if you don't care much for older browsers).

How to create tar.gz archive file in Windows?

tar.gz file is just a tar file that's been gzipped. Both tar and gzip are available for windows.

If you like GUIs (Graphical user interface), 7zip can pack with both tar and gzip.

How to find a text inside SQL Server procedures / triggers?

You can find it like


It will list distinct stored procedure names that contain text like 'User' inside stored procedure. More info

How to click a href link using Selenium

You can use this method:

For the links if you use linkText(); it is more effective than the any other locator.

driver.findElement(By.linkText("App Configuration")).click();

SSIS Connection Manager Not Storing SQL Password

There is easy way of doing this. I don't know why people are giving complicated answers.

Double click SSIS package. Then go to connection manager, select DestinationConnectionOLDB and then add password next to login field.

Example: Data Source=SysproDB1;User ID=test;password=test;Initial Catalog=ASBuiltDW;Provider=SQLNCLI11;Auto Translate=false;

Do same for SourceConnectionOLDB.

Removing Duplicate Values from ArrayList

List<String> list = new ArrayList<String>();

HashSet<String> hs=new HashSet<>(list);

System.out.println("=========With Duplicate Element========");
System.out.println("=========Removed Duplicate Element========");

Can't install any package with node npm

Adding a -g to the end of my install fixed this for me. ex: npm install uglify-js -g

Unique constraint violation during insert: why? (Oracle)

It looks like you are not providing a value for the primary key field DB_ID. If that is a primary key, you must provide a unique value for that column. The only way not to provide it would be to create a database trigger that, on insert, would provide a value, most likely derived from a sequence.

If this is a restoration from another database and there is a sequence on this new instance, it might be trying to reuse a value. If the old data had unique keys from 1 - 1000 and your current sequence is at 500, it would be generating values that already exist. If a sequence does exist for this table and it is trying to use it, you would need to reconcile the values in your table with the current value of the sequence.

You can use SEQUENCE_NAME.CURRVAL to see the current value of the sequence (if it exists of course)

Fast query runs slow in SSRS

In our case, no code was required.

Note from our Help Desk: "Clearing out your Internet Setting will fix this problem."

Maybe that means "clear cache."

How do I use a C# Class Library in a project?

  1. Add a reference to your library
  2. Import the namespace
  3. Consume the types in your library

wp_nav_menu change sub-menu class name?

This may be useful to you

How to add a parent class for menu item

function wpdocs_add_menu_parent_class( $items ) {
$parents = array();

// Collect menu items with parents.
foreach ( $items as $item ) {
    if ( $item->menu_item_parent && $item->menu_item_parent > 0 ) {
        $parents[] = $item->menu_item_parent;

// Add class.
foreach ( $items as $item ) {
    if ( in_array( $item->ID, $parents ) ) {
        $item->classes[] = 'menu-parent-item';
return $items;
add_filter( 'wp_nav_menu_objects', 'wpdocs_add_menu_parent_class' );

 * Add a parent CSS class for nav menu items.
 * @param array  $items The menu items, sorted by each menu item's menu order.
 * @return array (maybe) modified parent CSS class.

Adding Conditional Classes to Menu Items

function wpdocs_special_nav_class( $classes, $item ) {
    if ( is_single() && 'Blog' == $item->title ) {
    // Notice you can change the conditional from is_single() and $item->title
    $classes[] = "special-class";
return $classes;
add_filter( 'nav_menu_css_class' , 'wpdocs_special_nav_class' , 10, 2 );

For reference : click me

Swipe to Delete and the "More" button (like in Mail app on iOS 7)

I hope you cant wait till apple gives you what ever you need right? So here is my option.

Create a custom cell. Have two uiviews in it

1. upper
2. lower

In lower view, add what ever buttons you need. Deal its actions just like any other IBActions. you can decide the animation time, style and anything.

now add a uiswipegesture to the upper view and reveal your lower view on swipe gesture. I have done this before and its the simplest option as far as I am concerned.

Hope that help.

How I can check whether a page is loaded completely or not in web driver?

You can set a JavaScript variable in your WepPage that gets set once it's been loaded. You could put it anywhere, but if you're using jQuery, $(document).onReady isn't a bad place to start. If not, then you can put it in a <script> tag at the bottom of the page.

The advantage of this method as opposed to checking for element visibility is that you know the exact state of the page after the wait statement executes.


... All my page content ...
<script> window.TestReady = true; </script></body></html>

And in your test (C# example):

// The timespan determines how long to wait for any 'condition' to return a value
// If it is exceeded an exception is thrown.
WebDriverWait wait = new WebDriverWait(driver, TimeSpan.FromSeconds(5.0));

// Set the 'condition' as an anonymous function returning a boolean
wait.Until<Boolean>(delegate(IWebDriver d)
    // Check if our global variable is initialized by running a little JS
    return (Boolean)((IJavaScriptExecutor)d).ExecuteScript("return typeof(window.TestReady) !== 'undefined' && window.TestReady === true");

How to disable sort in DataGridView?

private void dataGridView1_DataBindingComplete(object sender, DataGridViewBindingCompleteEventArgs e)
      for (int i = 0; i < dataGridView1.Columns.Count; i++)
           dataGridView1.Columns[i].SortMode = DataGridViewColumnSortMode.NotSortable;

How to find all occurrences of an element in a list

more_itertools.locate finds indices for all items that satisfy a condition.

from more_itertools import locate

list(locate([0, 1, 1, 0, 1, 0, 0]))
# [1, 2, 4]

list(locate(['a', 'b', 'c', 'b'], lambda x: x == 'b'))
# [1, 3]

more_itertools is a third-party library > pip install more_itertools.

How to compare objects by multiple fields

If there are multiple ways a user might order person, you could also have multiple Comparators setup as constants somewhere. Most of the sort operations and sorted collections take a comparator as a parameter.

What is the documents directory (NSDocumentDirectory)?

This has changed in iOS 8. See the following tech note:

The Apple sanctioned way (from the link above) is as follows:

// Returns the URL to the application's Documents directory.
- (NSURL *)applicationDocumentsDirectory
    return [[[NSFileManager defaultManager] URLsForDirectory:NSDocumentDirectory inDomains:NSUserDomainMask] lastObject];

Is it possible to Turn page programmatically in UIPageViewController?

I'm working on It since yesterday and I finally did It work. I couldn't use standard template totally, because I have three differents viewControllers as childviews:

1 - rootViewController;
2 - model;
3 - viewControllers
3.1 - VC1;
3.2 - VC2;
3.3 - VC3.
Note: all of VCs has Storyboard ID.

I needed a trigger button only in the first one VC, so I added one property for pageViewController and model:

#import <UIKit/UIKit.h>
#import "Model.h"

@interface VC1 : UIViewController

@property (nonatomic, strong) UIPageViewController *thePageViewController;
@property (nonatomic, strong) SeuTimePagesModel *theModel;


I rewrote the model's init method to pass storyboard and pageViewController as parameters, so I could set those to my VC1:

- (id)initWithStoryboard:(UIStoryboard *)storyboard
   andPageViewController:(UIPageViewController *)controller
    if (self = [super init])
        VC1 *vc1 = [storyboard instantiateViewControllerWithIdentifier:@"VC1"];
        vc1.pageViewController = controller;
        vc1.model = self;

        VC2 *vc2 = [storyboard instantiateViewControllerWithIdentifier:@"VC2"];
        VC3 *vc3 = [storyboard instantiateViewControllerWithIdentifier:@"VC3"];
        self.pageData = [[NSArray alloc] initWithObjects:vc1, vc2, vc3, nil];

    return self;

Finally, I added an IBAction in my vc1 to trigger the pageViewController method setViewControllers:direction:animated:completion::

- (IBAction)go:(id)sender
    VC2 *vc2 = [_model.pages objectAtIndex:1];
    NSArray *viewControllers = @[vc2];
    [_pageViewController setViewControllers:viewControllers

Note I don't need to find VCs indexes, my button takes me to my second VC, but Its not hard get all of indexes, and keep track of your childviews:

- (IBAction)selecionaSeuTime:(id)sender
    NSUInteger index = [_model.pages indexOfObject:self];

    VC2 *vc2 = [_model.pages objectAtIndex:1];
    NSArray *viewControllers = @[vc2];
    [_pageViewController setViewControllers:viewControllers

I hope It helps you!

Java Round up Any Number

int RoundedUp = (int) Math.ceil(RandomReal);

This seemed to do the perfect job. Worked everytime.

Validation failed for one or more entities. See 'EntityValidationErrors' property for more details

If you're using IIS with Windows Authentification and Entity Framework, be careful to use authorize.

I tried to POST without authorize and it didn't work, and get this error on db.SaveChangesAsync();, while all other verbs GET and DELETE were working.

But when I added AuthorizeAttribute as annotation, it worked.

public async Task<IHttpActionResult> Post(...){

What is java pojo class, java bean, normal class?

POJO stands for Plain Old Java Object, and would be used to describe the same things as a "Normal Class" whereas a JavaBean follows a set of rules. Most commonly Beans use getters and setters to protect their member variables, which are typically set to private and have a no-argument public constructor. Wikipedia has a pretty good rundown of JavaBeans:

POJO is usually used to describe a class that doesn't need to be a subclass of anything, or implement specific interfaces, or follow a specific pattern.

JPA OneToMany not deleting child

class Employee {
     private Address address;

See here.

Checking on a thread / remove from list

Better way is to use Queue class:

Look at the good example code in the bottom of documentation page:

def worker():
    while True:
        item = q.get()

q = Queue()
for i in range(num_worker_threads):
     t = Thread(target=worker)
     t.daemon = True

for item in source():

q.join()       # block until all tasks are done

multiple conditions for JavaScript .includes() method

Another one!

let result_x000D_
const givenStr = 'A, X' //values separated by comma or space._x000D_
const allowed  = ['A', 'B']_x000D_
const given    = givenStr.split(/[\s,]+/).filter(v => v)_x000D_
console.log('given (array):', given)_x000D_
// given contains none or only allowed values:_x000D_
result = given.reduce((acc, val) => {_x000D_
  return acc && allowed.includes(val)_x000D_
}, true)_x000D_
console.log('given contains none or only allowed values:', result)_x000D_
// given contains at least one allowed value:_x000D_
result = given.reduce((acc, val) => {_x000D_
  return acc || allowed.includes(val)_x000D_
}, false)_x000D_
console.log('given contains at least one allowed value:', result)

How to run mysql command on bash?

I have written a shell script which will read data from properties file and then run mysql script on shell script. sharing this may help to others.


    function getProperty {
       PROP_VALUE=`cat $PROPERTY_FILE | grep "$PROP_KEY" | cut -d'=' -f2`
       echo $PROP_VALUE

    echo "# Reading property from $PROPERTY_FILE"
    DB_USER=$(getProperty "db.username")
    DB_PASS=$(getProperty "db.password")
    ROOT_LOC=$(getProperty "root.location")
    echo $DB_USER
    echo $DB_PASS
    echo $ROOT_LOC
    echo "Writing on DB ... "
    mysql -u$DB_USER -p$DB_PASS dbname<<EOFMYSQL

    update tablename set tablename.value_ = "$ROOT_LOC" where tablename.name_="Root directory location";
    echo "Writing root location($ROOT_LOC) is done ... "
    counter=`mysql -u${DB_USER} -p${DB_PASS} dbname -e "select count(*) from tablename where tablename.name_='Root directory location' and tablename.value_ = '$ROOT_LOC';" | grep -v "count"`;

    if [ "$counter" = "1" ]
    echo "ROOT location updated"

Replace Both Double and Single Quotes in Javascript String

You don't need to escape it inside. You can use the | character to delimit searches.

"\"foo\"\'bar\'".replace(/("|')/g, "")

Parse JSON from JQuery.ajax success data

I'm not sure whats going wrong with your set up. Maybe the server is not setting the headers properly. Not sure. As a long shot, you can try this

    url : url,
    dataType : 'json'
.done(function(data, statusText, resObject) {
   var jsonData = resObject.responseJSON

How to silence output in a Bash script?

Note: This answer is related to the question "How to turn off echo while executing a shell script Linux" which was in turn marked as duplicated to this one.

To actually turn off the echo the command is:

stty -echo

(this is, for instance; when you want to enter a password and you don't want it to be readable. Remember to turn echo on at the end of your script, otherwise the person that runs your script won't see what he/she types in from then on. To turn echo on run:

stty echo

Is Constructor Overriding Possible?

Because a constructor cannot be inherited in Java and Method Overriding requires inheritance. Therefore, it's not applicable.

jQuery Popup Bubble/Tooltip

Sounds to me you dn't want the mouse over events: you want the jQuery hover() event.

And what you seem to want is a "rich" tooltip, in which case I suggest jQuery tooltip. With the bodyHandler option you can put arbitrary HTML in.

How to replace case-insensitive literal substrings in Java

If you don't care about case, then you perhaps it doesn't matter if it returns all upcase:

target.toUpperCase().replace("FOO", "");

How to install JRE 1.7 on Mac OS X and use it with Eclipse?

You need to tell Eclipse which JDK/JRE's you have installed and where they are located.

This is somewhat burried in the Eclipse preferences: In the Window-Menu select "Preferences". In the Preferences Tree, open the Node "Java" and select "Installed JRE's". Then click on the "Add"-Button in the Panel and select "Standard VM", "Next" and for "JRE Home" click on the "Directory"-Button and select the top level folder of the JDK you want to add.

Its easier than the description may make it look.

Increase Tomcat memory settings

try setting this

CATALINA_OPTS="-Djava.awt.headless=true -Dfile.encoding=UTF-8 
-server -Xms1536m -Xmx1536m
-XX:NewSize=256m -XX:MaxNewSize=256m -XX:PermSize=256m 
-XX:MaxPermSize=256m -XX:+DisableExplicitGC"

in {$tomcat-folder}\bin\ (create it if necessary).

See for more details.

Best practice multi language website

I've been asking myself related questions over and over again, then got lost in formal languages... but just to help you out a little I'd like to share some findings:

I recommend to give a look at advanced CMS

Typo3 for PHP (I know there is a lot of stuff but thats the one I think is most mature)

Plone in Python

If you find out that the web in 2013 should work different then, start from scratch. That would mean to put together a team of highly skilled/experienced people to build a new CMS. May be you'd like to give a look at polymer for that purpose.

If it comes to coding and multilingual websites / native language support, I think every programmer should have a clue about unicode. If you don't know unicode you'll most certainly mess up your data. Do not go with the thousands of ISO codes. They'll only save you some memory. But you can do literally everything with UTF-8 even store chinese chars. But for that you'd need to store either 2 or 4 byte chars that makes it basically a utf-16 or utf-32.

If it's about URL encoding, again there you shouldn't mix encodings and be aware that at least for the domainname there are rules defined by different lobbies that provide applications like a browser. e.g. a Domain could be very similar like:

? or samesamebutdifferent ;)

Of course you need the filesystem to work with all encodings. Another plus for unicode using utf-8 filesystem.

If its about translations, think about the structure of documents. e.g. a book or an article. You have the docbook specifications to understand about those structures. But in HTML its just about content blocks. So you'd like to have a translation on that level, also on webpage level or domain level. So if a block doesn't exist its just not there, if a webpage doesn't exist you'll get redirected to the upper navigation level. If a domain should be completely different in navigation structure, then.. its a complete different structure to manage. This can already be done with Typo3.

If its about frameworks, the most mature ones I know, to do the general stuff like MVC(buzzword I really hate it! Like "performance" If you want to sell something, use the word performance and featurerich and you sell... what the hell) is Zend. It has proven to be a good thing to bring standards to php chaos coders. But, typo3 also has a Framework besides the CMS. Recently it has been redeveloped and is called flow3 now. The frameworks of course cover database abstraction, templating and concepts for caching, but have individual strengths.

If its about caching... that can be awefully complicated / multilayered. In PHP you'll think about accellerator, opcode, but also html, httpd, mysql, xml, css, js ... any kinds of caches. Of course some parts should be cached and dynamic parts like blog answers shouldn't. Some should be requested over AJAX with generated urls. JSON, hashbangs etc.

Then, you'd like to have any little component on your website to be accessed or managed only by certain users, so conceptually that plays a big role.

Also you'd like to make statistics, maybe have distributed system / a facebook of facebooks etc. any software to be built on top of your over the top cms ... so you need different type of databases inmemory, bigdata, xml, whatsoever.

well, I think thats enough for now. If you haven't heard of either typo3 / plone or mentioned frameworks, you have enough to study. On that path you'll find a lot of solutions for questions you haven't asked yet.

If then you think, lets make a new CMS because its 2013 and php is about to die anyway, then you r welcome to join any other group of developers hopefully not getting lost.

Good luck!

And btw. how about people will not having any websites anymore in the future? and we'll all be on google+? I hope developers become a little more creative and do something usefull(to not be assimilated by the borgle)

//// Edit /// Just a little thought for your existing application:

If you have a php mysql CMS and you wanted to embed multilang support. you could either use your table with an aditional column for any language or insert the translation with an object id and a language id in the same table or create an identical table for any language and insert objects there, then make a select union if you want to have them all displayed. For the database use utf8 general ci and of course in the front/backend use utf8 text/encoding. I have used url path segments for urls in the way you already explaned like you can map the lang ID to your content table. anyway you need to have a map of parameters for your urls so you'd like to define a parameter to be mapped from a pathsegment in your URL that would be e.g.

lookup configuration

pageid| url

1 | /about/employees/../..

1 | /../about/employees../../

map parameters to url pathsegment ""

$parameterlist[lang] = array(0=>"nl",1=>"en"); // default nl if 0
$parameterlist[branch] = array(1=>"IT",2=>"DESIGN"); // default nl if 0
$parameterlist[employertype] = array(1=>"admin",1=>"engineer"); //could be a sql result 

$someparameterlist[] = array("branch"=>$someid);
$someparameterlist[] = array("employertype"=>$someid);
function getURL($someparameterlist){ 
// todo foreach someparameter lookup pathsegment 
return path;

per say, thats been covered already in upper post.

And to not forget, you'd need to "rewrite" the url to your generating php file that would in most cases be index.php

How to get image size (height & width) using JavaScript?

Let's combine everything we learned here into one simple function (imageDimensions()). It uses promises.

// helper to get dimensions of an image
const imageDimensions = file => 
    new Promise((resolve, reject) => {
        const img = new Image()

        // the following handler will fire after the successful loading of the image
        img.onload = () => {
            const { naturalWidth: width, naturalHeight: height } = img
            resolve({ width, height })

        // and this handler will fire if there was an error with the image (like if it's not really an image or a corrupted one)
        img.onerror = () => {
            reject('There was some problem with the image.')
        img.src = URL.createObjectURL(file)

// here's how to use the helper
const getInfo = async ({ target: { files } }) => {
    const [file] = files
    try {
        const dimensions = await imageDimensions(file)
    } catch(error) {
<script src=""></script>

Select an image:
<br />
<small>It works offline.</small>

Fastest way to flatten / un-flatten nested JSON objects

ES6 version:

const flatten = (obj, path = '') => {        
    if (!(obj instanceof Object)) return {[path.replace(/\.$/g, '')]:obj};

    return Object.keys(obj).reduce((output, key) => {
        return obj instanceof Array ? 
             {...output, ...flatten(obj[key], path +  '[' + key + '].')}:
             {...output, ...flatten(obj[key], path + key + '.')};
    }, {});



Select and display only duplicate records in MySQL

Try this query:

SELECT id, COUNT( payer_email ) `tot`
FROM paypal_ipn_orders
HAVING `tot` >1

Does it help?

jQuery selectors on custom data attributes using HTML5

jQuery UI has a :data() selector which can also be used. It has been around since Version 1.7.0 it seems.

You can use it like this:

Get all elements with a data-company attribute

var companyElements = $("ul:data(group) li:data(company)");

Get all elements where data-company equals Microsoft

var microsoft = $("ul:data(group) li:data(company)")
                    .filter(function () {
                        return $(this).data("company") == "Microsoft";

Get all elements where data-company does not equal Microsoft

var notMicrosoft = $("ul:data(group) li:data(company)")
                       .filter(function () {
                           return $(this).data("company") != "Microsoft";


One caveat of the new :data() selector is that you must set the data value by code for it to be selected. This means that for the above to work, defining the data in HTML is not enough. You must first do this:

$("li").first().data("company", "Microsoft");

This is fine for single page applications where you are likely to use $(...).data("datakey", "value") in this or similar ways.

How display only years in input Bootstrap Datepicker?

format: "YYYY" 

Should be capital instead of "yyyy"

Converting BigDecimal to Integer


Use one of these for universal conversion needs

//Java 7 or below
bigDecimal.setScale(0, RoundingMode.DOWN).intValueExact()
//Java 8    


The answer depends on what the requirements are and how you answer these question.

  • Will the BigDecimal potentially have a non-zero fractional part?
  • Will the BigDecimal potentially not fit into the Integer range?
  • Would you like non-zero fractional parts rounded or truncated?
  • How would you like non-zero fractional parts rounded?

If you answered no to the first 2 questions, you could just use BigDecimal.intValueExact() as others have suggested and let it blow up when something unexpected happens.

If you are not absolutely 100% confident about question number 2, then intValue() is always the wrong answer.

Making it better

Let's use the following assumptions based on the other answers.

  • We are okay with losing precision and truncating the value because that's what intValueExact() and auto-boxing do
  • We want an exception thrown when the BigDecimal is larger than the Integer range because anything else would be crazy unless you have a very specific need for the wrap around that happens when you drop the high-order bits.

Given those params, intValueExact() throws an exception when we don't want it to if our fractional part is non-zero. On the other hand, intValue() doesn't throw an exception when it should if our BigDecimal is too large.

To get the best of both worlds, round off the BigDecimal first, then convert. This also has the benefit of giving you more control over the rounding process.

Spock Groovy Test

void 'test BigDecimal rounding'() {
    BigDecimal decimal = new BigDecimal(Integer.MAX_VALUE - 1.99)
    BigDecimal hugeDecimal = new BigDecimal(Integer.MAX_VALUE + 1.99)
    BigDecimal reallyHuge = new BigDecimal("10000000000000000000000000000000000000000000000")
    String decimalAsBigIntString = decimal.toBigInteger().toString()
    String hugeDecimalAsBigIntString = hugeDecimal.toBigInteger().toString()
    String reallyHugeAsBigIntString = reallyHuge.toBigInteger().toString()

    expect: 'decimals that can be truncated within Integer range to do so without exception'
    //GOOD: Truncates without exception
    '' + decimal.intValue() == decimalAsBigIntString
    //BAD: Throws ArithmeticException 'Non-zero decimal digits' because we lose information
    // decimal.intValueExact() == decimalAsBigIntString
    //GOOD: Truncates without exception
    '' + decimal.setScale(0, RoundingMode.DOWN).intValueExact() == decimalAsBigIntString

    and: 'truncated decimal that cannot be truncated within Integer range throw conversionOverflow exception'
    //BAD: hugeDecimal.intValue() is -2147483648 instead of 2147483648
    //'' + hugeDecimal.intValue() == hugeDecimalAsBigIntString
    //BAD: Throws ArithmeticException 'Non-zero decimal digits' because we lose information
    //'' + hugeDecimal.intValueExact() == hugeDecimalAsBigIntString
    //GOOD: Throws conversionOverflow ArithmeticException because to large
    //'' + hugeDecimal.setScale(0, RoundingMode.DOWN).intValueExact() == hugeDecimalAsBigIntString

    and: 'truncated decimal that cannot be truncated within Integer range throw conversionOverflow exception'
    //BAD: hugeDecimal.intValue() is 0
    //'' + reallyHuge.intValue() == reallyHugeAsBigIntString
    //GOOD: Throws conversionOverflow ArithmeticException because to large
    //'' + reallyHuge.intValueExact() == reallyHugeAsBigIntString
    //GOOD: Throws conversionOverflow ArithmeticException because to large
    //'' + reallyHuge.setScale(0, RoundingMode.DOWN).intValueExact() == reallyHugeAsBigIntString

    and: 'if using Java 8, BigInteger has intValueExact() just like BigDecimal'
    //decimal.toBigInteger().intValueExact() == decimal.setScale(0, RoundingMode.DOWN).intValueExact()

is it possible to evenly distribute buttons across the width of an android linearlayout

In linearLayout Instead of giving weight to Button itself , set the weight to <Space> View this won't stretch the Button.

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


            android:layout_weight="1" />

            android:background="@drawable/ic_baseline_arrow_back_24" />

            android:layout_weight="1" />

            android:background="@drawable/ic_round_camera_24" />

            android:layout_weight="1" />

            android:background="@drawable/ic_round_switch_camera_24" />

            android:layout_weight="1" />


as I am using 4 <Space> I set the android:weightSum="4" In linear layout also this is the result ::

layout preview

String comparison in Objective-C

You can use case-sensitive or case-insensitive comparison, depending what you need. Case-sensitive is like this:

if ([category isEqualToString:@"Some String"])
   // Both strings are equal without respect to their case.

Case-insensitive is like this:

if ([category compare:@"Some String" options:NSCaseInsensitiveSearch] == NSOrderedSame)
   // Both strings are equal with respect to their case.

malloc an array of struct pointers

I agree with @maverik above, I prefer not to hide the details with a typedef. Especially when you are trying to understand what is going on. I also prefer to see everything instead of a partial code snippet. With that said, here is a malloc and free of a complex structure.

The code uses the ms visual studio leak detector so you can experiment with the potential leaks.

#include "stdafx.h"

#include <string.h>
#include "msc-lzw.h"

#include <stdlib.h>
#include <crtdbg.h> 

// 32-bit version
int hash_fun(unsigned int key, int try_num, int max) {
    return (key + try_num) % max;  // the hash fun returns a number bounded by the number of slots.

// this hash table has
// key is int
// value is char buffer
struct key_value_pair {
    int key; // use this field as the key
    char *pValue;  // use this field to store a variable length string

struct hash_table {
    int max;
    int number_of_elements;
    struct key_value_pair **elements;  // This is an array of pointers to mystruct objects

int hash_insert(struct key_value_pair *data, struct hash_table *hash_table) {

    int try_num, hash;
    int max_number_of_retries = hash_table->max;

    if (hash_table->number_of_elements >= hash_table->max) {
        return 0; // FULL

    for (try_num = 0; try_num < max_number_of_retries; try_num++) {

        hash = hash_fun(data->key, try_num, hash_table->max);

        if (NULL == hash_table->elements[hash]) { // an unallocated slot
            hash_table->elements[hash] = data;
            return RC_OK;
    return RC_ERROR;

// returns the corresponding key value pair struct
// If a value is not found, it returns null
// 32-bit version
struct key_value_pair *hash_retrieve(unsigned int key, struct hash_table *hash_table) {

    unsigned int try_num, hash;
    unsigned int max_number_of_retries = hash_table->max;

    for (try_num = 0; try_num < max_number_of_retries; try_num++) {

        hash = hash_fun(key, try_num, hash_table->max);

        if (hash_table->elements[hash] == 0) {
            return NULL; // Nothing found

        if (hash_table->elements[hash]->key == key) {
            return hash_table->elements[hash];
    return NULL;

// Returns the number of keys in the dictionary
// The list of keys in the dictionary is returned as a parameter.  It will need to be freed afterwards
int keys(struct hash_table *pHashTable, int **ppKeys) {

    int num_keys = 0;

    *ppKeys = (int *) malloc( pHashTable->number_of_elements * sizeof(int) );

    for (int i = 0; i < pHashTable->max; i++) {
        if (NULL != pHashTable->elements[i]) {
            (*ppKeys)[num_keys] = pHashTable->elements[i]->key;
    return num_keys;

// The dictionary will need to be freed afterwards
int allocate_the_dictionary(struct hash_table *pHashTable) {

    // Allocate the hash table slots
    pHashTable->elements = (struct key_value_pair **) malloc(pHashTable->max * sizeof(struct key_value_pair));  // allocate max number of key_value_pair entries
    for (int i = 0; i < pHashTable->max; i++) {
        pHashTable->elements[i] = NULL;

    // alloc all the slots
    //struct key_value_pair *pa_slot;
    //for (int i = 0; i < pHashTable->max; i++) {
    //  // all that he could see was babylon
    //  pa_slot = (struct key_value_pair *)  malloc(sizeof(struct key_value_pair));
    //  if (NULL == pa_slot) {
    //      printf("alloc of slot failed\n");
    //      while (1);
    //  }
    //  pHashTable->elements[i] = pa_slot;
    //  pHashTable->elements[i]->key = 0;

    return RC_OK;

// This will make a dictionary entry where
//   o  key is an int
//   o  value is a character buffer
// The buffer in the key_value_pair will need to be freed afterwards
int make_dict_entry(int a_key, char * buffer, struct key_value_pair *pMyStruct) {

    // determine the len of the buffer assuming it is a string
    int len = strlen(buffer);

    // alloc the buffer to hold the string
    pMyStruct->pValue = (char *) malloc(len + 1); // add one for the null terminator byte
    if (NULL == pMyStruct->pValue) {
        printf("Failed to allocate the buffer for the dictionary string value.");
        return RC_ERROR;
    strcpy(pMyStruct->pValue, buffer);
    pMyStruct->key = a_key;

    return RC_OK;

// Assumes the hash table has already been allocated.
int add_key_val_pair_to_dict(struct hash_table *pHashTable, int key, char *pBuff) {

    int rc;
    struct key_value_pair *pKeyValuePair;

    if (NULL == pHashTable) {
        printf("Hash table is null.\n");
        return RC_ERROR;

    // Allocate the dictionary key value pair struct
    pKeyValuePair = (struct key_value_pair *) malloc(sizeof(struct key_value_pair));
    if (NULL == pKeyValuePair) {
        printf("Failed to allocate key value pair struct.\n");
        return RC_ERROR;

    rc = make_dict_entry(key, pBuff, pKeyValuePair);  // a_hash_table[1221] = "abba"
    if (RC_ERROR == rc) {
        printf("Failed to add buff to key value pair struct.\n");
        return RC_ERROR;

    rc = hash_insert(pKeyValuePair, pHashTable);
    if (RC_ERROR == rc) {
        printf("insert has failed!\n");
        return RC_ERROR;

    return RC_OK;

void dump_hash_table(struct hash_table *pHashTable) {

    // Iterate the dictionary by keys
    char * pValue;
    struct key_value_pair *pMyStruct;
    int *pKeyList;
    int num_keys;

    num_keys = keys(pHashTable, &pKeyList);
    for (int i = 0; i < num_keys; i++) {
        pMyStruct = hash_retrieve(pKeyList[i], pHashTable);
        pValue = pMyStruct->pValue;
        printf("%d\t%d\t%s\n", i, pKeyList[i], pValue);

    // Free the key list


int main(int argc, char *argv[]) {

    int rc;
    int i;

    struct hash_table a_hash_table;
    a_hash_table.max = 20;   // The dictionary can hold at most 20 entries.
    a_hash_table.number_of_elements = 0;  // The intial dictionary has 0 entries.

    rc = add_key_val_pair_to_dict(&a_hash_table, 1221, "abba");
    if (RC_ERROR == rc) {
        printf("insert has failed!\n");
        return RC_ERROR;
    rc = add_key_val_pair_to_dict(&a_hash_table, 2211, "bbaa");
    if (RC_ERROR == rc) {
        printf("insert has failed!\n");
        return RC_ERROR;
    rc = add_key_val_pair_to_dict(&a_hash_table, 1122, "aabb");
    if (RC_ERROR == rc) {
        printf("insert has failed!\n");
        return RC_ERROR;
    rc = add_key_val_pair_to_dict(&a_hash_table, 2112, "baab");
    if (RC_ERROR == rc) {
        printf("insert has failed!\n");
        return RC_ERROR;
    rc = add_key_val_pair_to_dict(&a_hash_table, 1212, "abab");
    if (RC_ERROR == rc) {
        printf("insert has failed!\n");
        return RC_ERROR;
    rc = add_key_val_pair_to_dict(&a_hash_table, 2121, "baba");
    if (RC_ERROR == rc) {
        printf("insert has failed!\n");
        return RC_ERROR;

    // Iterate the dictionary by keys

    // Free the individual slots
    for (i = 0; i < a_hash_table.max; i++) {
        // all that he could see was babylon
        if (NULL != a_hash_table.elements[i]) {
            free(a_hash_table.elements[i]->pValue);  // free the buffer in the struct
            free(a_hash_table.elements[i]);  // free the key_value_pair entry
            a_hash_table.elements[i] = NULL;

    // Free the overall dictionary

    return 0;

Converting HTML to PDF using PHP?

If you wish to create a pdf from php, pdflib will help you (as some others suggested).

Else, if you want to convert an HTML page to PDF via PHP, you'll find a little trouble outta here.. For 3 years I've been trying to do it as best as I can.

So, the options I know are:

DOMPDF : php class that wraps the html and builds the pdf. Works good, customizable (if you know php), based on pdflib, if I remember right it takes even some CSS. Bad news: slow when the html is big or complex.

HTML2PS: same as DOMPDF, but this one converts first to a .ps (ghostscript) file, then, to whatever format you need (pdf, jpg, png). For me is little better than dompdf, but has the same speed problem.. but, better compatibility with CSS.

Those two are php classes, but if you can install some software on the server, and access it throught passthru() or system(), give a look to these too:

wkhtmltopdf: based on webkit (safari's wrapper), is really fast and powerful.. seems like this is the best one (atm) for converting html pages to pdf on the fly; taking only 2 seconds for a 3 page xHTML document with CSS2. It is a recent project, anyway, the google.code page is often updated.

htmldoc : This one is a tank, it never really stops/crashes.. the project looks dead since 2007, but anyway if you don't need CSS compatibility this can be nice for you.

Adding a Method to an Existing Object Instance

You can use lambda to bind a method to an instance:

def run(self):
    print self._instanceString

class A(object):
    def __init__(self):
        self._instanceString = "This is instance string"

a = A() = lambda: run(a)


This is instance string

Add an object to a python list

while you should show how your code looks like that gives the problem, i think this scenario is very common. See copy/deepcopy

Compare a string using sh shell

You should use the = operator for string comparison:


if [ "$Sourcesystem" = "XYZ" ]; then 
    echo "Sourcesystem Matched" 
    echo "Sourcesystem is NOT Matched $Sourcesystem"  

man test says that you use -z to match for empty strings.

ConfigurationManager.AppSettings - How to modify and save?

I know I'm late :) But this how i do it:

public static void AddOrUpdateAppSettings(string key, string value)
        var configFile = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);
        var settings = configFile.AppSettings.Settings;
        if (settings[key] == null)
            settings.Add(key, value);
            settings[key].Value = value;
    catch (ConfigurationErrorsException)
        Console.WriteLine("Error writing app settings");

For more information look at MSDN

Web Reference vs. Service Reference

Add Web Reference is the old-style, deprecated ASP.NET webservices (ASMX) technology (using only the XmlSerializer for your stuff) - if you do this, you get an ASMX client for an ASMX web service. You can do this in just about any project (Web App, Web Site, Console App, Winforms - you name it).

Add Service Reference is the new way of doing it, adding a WCF service reference, which gives you a much more advanced, much more flexible service model than just plain old ASMX stuff.

Since you're not ready to move to WCF, you can also still add the old-style web reference, if you really must: when you do a "Add Service Reference", on the dialog that comes up, click on the [Advanced] button in the button left corner:

alt text

and on the next dialog that comes up, pick the [Add Web Reference] button at the bottom.

How can I search (case-insensitive) in a column using LIKE wildcard?

You don't need to ALTER any table. Just use the following queries, prior to the actual SELECT query that you want to use the wildcard:

    set names `utf8`;
    SET COLLATION_CONNECTION=utf8_general_ci;

How can I change a button's color on hover?

    background: #383;  }

works for me but in my case

#buttonClick:hover {
background-color:green;  }

Apache Tomcat Connection refused

There is one more explanation for this Connection Refused problem, that I missed from answers above. In my case I had thread running (quartz scheduler) started from context listener (in contextInitialized), never to be stopped (like in contextDestroyed).

This in turn caused the server port associated to be closed, where as the container kept on running (hence: connection refused on the server port).

I fixed it stopping quartz in contextDestroyed and I didn't experience this issue ever since.

See here for similar issues: Tomcat doesn't stop. How can I debug this?

How to get text from EditText?

The quickest solution to your problem I believe is that you simply are missing parentheses on your getText. Simply add () to edit.getText().toString() and that should solve it

What's the difference between import java.util.*; and import java.util.Date; ?

import java.util.*;

imports everything within java.util including the Date class.

import java.util.Date;

just imports the Date class.

Doing either of these could not make any difference.

How to use git merge --squash?

For Git

Create a new feature

via Terminal/Shell:

git checkout origin/feature/<featurename>
git merge --squash origin/feature/<featurename>

This doesnt commit it, allows you to review it first.

Then commit, and finish feature from this new branch, and delete/ignore the old one (the one you did dev on).

How to find locked rows in Oracle

Rather than locks, I suggest you look at long-running transactions, using v$transaction. From there you can join to v$session, which should give you an idea about the UI (try the program and machine columns) as well as the user.

Remove all constraints affecting a UIView

A Swift solution:

extension UIView {
  func removeAllConstraints() {
    var view: UIView? = self
    while let currentView = view {
      currentView.removeConstraints(currentView.constraints.filter {
        return $0.firstItem as? UIView == self || $0.secondItem as? UIView == self
      view = view?.superview

It's important to go through all the parents, since the constraints between two elements are holds by the common ancestors, so just clearing the superview as detailed in this answer is not good enough, and you might end up having bad surprise later on.

How to loop through file names returned by find?

I like to use find which is first assigned to variable and IFS switched to new line as follow:

FilesFound=$(find . -name "*.txt")

for file in $FilesFound; do
    echo "${counter}: ${file}"
    let counter++;

As commented by @Konrad Rudolph this will not work with "new lines" in file name. I still think it is handy as it covers most of the cases when you need to loop over command output.

Draw in Canvas by finger, Android

You can use this class simply:

public class DoodleCanvas  extends View{

    private Paint mPaint;
    private Path mPath;

    public DoodleCanvas(Context context, AttributeSet attrs) {
        super(context, attrs);
        mPaint = new Paint();
        mPath = new Path();

    protected void onDraw(Canvas canvas) {
        canvas.drawPath(mPath, mPaint);

    public boolean onTouchEvent(MotionEvent event) {

        switch (event.getAction()){

            case MotionEvent.ACTION_DOWN:
                mPath.moveTo(event.getX(), event.getY());

            case MotionEvent.ACTION_MOVE:
                mPath.lineTo(event.getX(), event.getY());

            case MotionEvent.ACTION_UP:

        return true;

Add text at the end of each line

You could try using something like:

sed -n 's/$/:80/' ips.txt > new-ips.txt

Provided that your file format is just as you have described in your question.

The s/// substitution command matches (finds) the end of each line in your file (using the $ character) and then appends (replaces) the :80 to the end of each line. The ips.txt file is your input file... and new-ips.txt is your newly-created file (the final result of your changes.)

Also, if you have a list of IP numbers that happen to have port numbers attached already, (as noted by Vlad and as given by aragaer,) you could try using something like:

sed '/:[0-9]*$/ ! s/$/:80/' ips.txt > new-ips.txt

So, for example, if your input file looked something like this (note the :80):

The final result would look something like this:

Python str vs unicode types

Your terminal happens to be configured to UTF-8.

The fact that printing a works is a coincidence; you are writing raw UTF-8 bytes to the terminal. a is a value of length two, containing two bytes, hex values C3 and A1, while ua is a unicode value of length one, containing a codepoint U+00E1.

This difference in length is one major reason to use Unicode values; you cannot easily measure the number of text characters in a byte string; the len() of a byte string tells you how many bytes were used, not how many characters were encoded.

You can see the difference when you encode the unicode value to different output encodings:

>>> a = 'á'
>>> ua = u'á'
>>> ua.encode('utf8')
>>> ua.encode('latin1')
>>> a

Note that the first 256 codepoints of the Unicode standard match the Latin 1 standard, so the U+00E1 codepoint is encoded to Latin 1 as a byte with hex value E1.

Furthermore, Python uses escape codes in representations of unicode and byte strings alike, and low code points that are not printable ASCII are represented using \x.. escape values as well. This is why a Unicode string with a code point between 128 and 255 looks just like the Latin 1 encoding. If you have a unicode string with codepoints beyond U+00FF a different escape sequence, \u.... is used instead, with a four-digit hex value.

It looks like you don't yet fully understand what the difference is between Unicode and an encoding. Please do read the following articles before you continue:

How to add the JDBC mysql driver to an Eclipse project?

You can paste the .jar file of the driver in the Java setup instead of adding it to each project that you create. Paste it in C:\Program Files\Java\jre7\lib\ext or wherever you have installed java.

After this you will find that the .jar driver is enlisted in the library folder of your created project(JRE system library) in the IDE. No need to add it repetitively.

Setting DataContext in XAML in WPF

First of all you should create property with employee details in the Employee class:

public class Employee
    public Employee()
        EmployeeDetails = new EmployeeDetails();
        EmployeeDetails.EmpID = 123;
        EmployeeDetails.EmpName = "ABC";

    public EmployeeDetails EmployeeDetails { get; set; }

If you don't do that, you will create instance of object in Employee constructor and you lose reference to it.

In the XAML you should create instance of Employee class, and after that you can assign it to DataContext.

Your XAML should look like this:

<Window x:Class="SampleApplication.MainWindow"
    Title="MainWindow" Height="350" Width="525"
        <local:Employee x:Key="Employee" />
    <Grid DataContext="{StaticResource Employee}">
            <RowDefinition Height="Auto" />
            <RowDefinition Height="Auto" />
            <ColumnDefinition Width="Auto" />
            <ColumnDefinition Width="200" />

        <Label Grid.Row="0" Grid.Column="0" Content="ID:"/>
        <Label Grid.Row="1" Grid.Column="0" Content="Name:"/>
        <TextBox Grid.Column="1" Grid.Row="0" Margin="3" Text="{Binding EmployeeDetails.EmpID}" />
        <TextBox Grid.Column="1" Grid.Row="1" Margin="3" Text="{Binding EmployeeDetails.EmpName}" />

Now, after you created property with employee details you should binding by using this property:

Text="{Binding EmployeeDetails.EmpID}"

Understanding dispatch_async

Swift version

This is the Swift version of David's Objective-C answer. You use the global queue to run things in the background and the main queue to update the UI. .background).async {
    // Background Thread
    DispatchQueue.main.async {
        // Run UI Updates

Trying to start a service on boot on Android

This is what I did

1. I made the Receiver class

public class BootReceiver extends BroadcastReceiver {
    public void onReceive(Context context, Intent intent) {
        //whatever you want to do on boot
       Intent serviceIntent = new Intent(context, YourService.class);
} the manifest

    <uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED"/>
        <receiver android:name=".BootReceiver" android:enabled="true" android:exported="false">
                <action android:name="android.intent.action.BOOT_COMPLETED" />

3.and after ALL you NEED to "set" the receiver in your MainActivity, it may be inside the onCreate

 final ComponentName onBootReceiver = new ComponentName(getApplication().getPackageName(), BootReceiver.class.getName());
        if(getPackageManager().getComponentEnabledSetting(onBootReceiver) != PackageManager.COMPONENT_ENABLED_STATE_ENABLED)

the final steap I have learned from ApiDemos

How do I create a transparent Activity on Android?

It goes like this:

<activity android:name=".usual.activity.Declaration" android:theme="@android:style/Theme.Translucent.NoTitleBar" />

How to retrieve data from sqlite database in android and display it in TextView

You are using getData() method as void.

You can not return values from void.

Align vertically using CSS 3

a couple ways:

1. Absolute positioning-- you need to have a declared height to make this work:

   <div class='center'>Hey</div>

div {height: 100%; width: 100%; position: relative} {
     width: 100px;
     height: 100px;
     top: 50%;
     margin-top: -50px;

*2. Use display: table *

     <img src="/img.png" />
     <div class="text">text centered with image</div>

div {
     display: table;
     vertical-align: middle

div img,
div.text {
     display: table-cell;
     vertical-align: middle
  1. A more detailed tutorial using display: table

Unrecognized attribute 'targetFramework'. Note that attribute names are case-sensitive

Follow these two steps:

Register the .net framework version version 4.0 (if it is not registered)

  1. C:\WINDOWS\Microsoft.NET\Framework\v4.0.30319>aspnet_regiis -i

  2. In the app pool change the .net framework to v4.0

Counting repeated elements in an integer array

public static void main(String[] args) {
    Scanner input=new Scanner(;
    int[] numbers=new int[5];
    String x=null;
    System.out.print("enter the number 10:"+"/n");
    for(int i=0;i<5;i++){
        numbers[i] = input.nextInt();
    System.out.print("Numbers  :  count"+"\n");
    int count=1;
    for(int z=0;z<5;z++){
        for(int j=0;j<z;j++){
            if(numbers[z]==numbers[j] & j!=z){
        System.out.print(numbers[z]+" - "+count+"\n");


Correct format specifier to print pointer or address?

You can use %x or %X or %p; all of them are correct.

  • If you use %x, the address is given as lowercase, for example: a3bfbc4
  • If you use %X, the address is given as uppercase, for example: A3BFBC4

Both of these are correct.

If you use %x or %X it's considering six positions for the address, and if you use %p it's considering eight positions for the address. For example:

Select every Nth element in CSS

Try this


How do I fix a "Performance counter registry hive consistency" when installing SQL Server R2 Express?

Use Rafael's solution:

Added data from link to avoid link rot..

put this at any Console application:

string.Format("{0,3}", CultureInfo.InstalledUICulture.Parent.LCID.ToString("X")).Replace(" ", "0");

Watch the result. At mine it was "016".

Then you go to the registry at this key:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Perflib

and create another one with the name you got from the string.Format result.

In my case:

"HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Perflib\016"

and copy the info that is on any other key in this Perflib to this key you just created. Run the instalation again.

Just run the script and get your 3 digit code. Then follow his simple and quick steps, and you're ready to go!


SignalR Console app example

This is for dot net core 2.1 - after a lot of trial and error I finally got this to work flawlessly:

var url = "Hub URL goes here";

var connection = new HubConnectionBuilder()
    .WithAutomaticReconnect() //I don't think this is totally required, but can't hurt either

//Start the connection
var t = connection.StartAsync();

//Wait for the connection to complete

//Make your call - but in this case don't wait for a response 
//if your goal is to set it and forget it
await connection.InvokeAsync("SendMessage", "User-Server", "Message from the server");

This code is from your typical SignalR poor man's chat client. The problem that I and what seems like a lot of other people have run into is establishing a connection before attempting to send a message to the hub. This is critical, so it is important to wait for the asynchronous task to complete - which means we are making it synchronous by waiting for the task to complete.

python 2.7: cannot pip on windows "bash: pip: command not found"

On windows 7, you have to use this command: python -m pip install xxx. All above don't work for me.

The Completest Cocos2d-x Tutorial & Guide List

Here you got complementaries discussions about the topic, it can be interesting.



Get full query string in C# ASP.NET

Just use Request.QueryString.ToString() to get full query string, like this:

string URL = ""+Request.Querystring.ToString();

What is the difference between bottom-up and top-down?

Top down and bottom up DP are two different ways of solving the same problems. Consider a memoized (top down) vs dynamic (bottom up) programming solution to computing fibonacci numbers.

fib_cache = {}

def memo_fib(n):
  global fib_cache
  if n == 0 or n == 1:
     return 1
  if n in fib_cache:
     return fib_cache[n]
  ret = memo_fib(n - 1) + memo_fib(n - 2)
  fib_cache[n] = ret
  return ret

def dp_fib(n):
   partial_answers = [1, 1]
   while len(partial_answers) <= n:
     partial_answers.append(partial_answers[-1] + partial_answers[-2])
   return partial_answers[n]

print memo_fib(5), dp_fib(5)

I personally find memoization much more natural. You can take a recursive function and memoize it by a mechanical process (first lookup answer in cache and return it if possible, otherwise compute it recursively and then before returning, you save the calculation in the cache for future use), whereas doing bottom up dynamic programming requires you to encode an order in which solutions are calculated, such that no "big problem" is computed before the smaller problem that it depends on.

jQuery jump or scroll to certain position, div or target on the page from button onclick

$("html, body").scrollTop($(element).offset().top); // <-- Also integer can be used

jquery clear input default value

Unless you're really worried about older browsers, you could just use the new html5 placeholder attribute like so:

<input type="text" name="email" placeholder="Email address" class="input" />

Is there a wikipedia API just for retrieve content summary?

You can also get content such as the first pagagraph via DBPedia which takes Wikipedia content and creates structured information from it (RDF) and makes this available via an API. The DBPedia API is a SPARQL one (RDF-based) but it outputs JSON and it is pretty easy to wrap.

As an example here's a super simple JS library named WikipediaJS that can extract structured content including a summary first paragraph:

You can read more about it in this blog post:

The JS library code can be found here:

fork: retry: Resource temporarily unavailable

Another possibility is too many threads. We just ran into this error message when running a test harness against an app that uses a thread pool. We used

watch -n 5 -d "ps -eL <java_pid> | wc -l"

to watch the ongoing count of Linux native threads running within the given Java process ID. After this hit about 1,000 (for us--YMMV), we started getting the error message you mention.