Programs & Examples On #Pythonce

Add item to array in VBScript

Based on Charles Clayton's answer, but slightly simplified...

' add item to array
Sub ArrayAdd(arr, val)
    ReDim Preserve arr(UBound(arr) + 1)
    arr(UBound(arr)) = val
End Sub

Used like so

a = Array()
AddItem(a, 5)
AddItem(a, "foo")

Linux/Unix command to determine if process is running?

While pidof and pgrep are great tools for determining what's running, they are both, unfortunately, unavailable on some operating systems. A definite fail safe would be to use the following: ps cax | grep command

The output on Gentoo Linux:

14484 ?        S      0:00 apache2
14667 ?        S      0:00 apache2
19620 ?        Sl     0:00 apache2
21132 ?        Ss     0:04 apache2

The output on OS X:

42582   ??  Z      0:00.00 (smbclient)
46529   ??  Z      0:00.00 (smbclient)
46539   ??  Z      0:00.00 (smbclient)
46547   ??  Z      0:00.00 (smbclient)
46586   ??  Z      0:00.00 (smbclient)
46594   ??  Z      0:00.00 (smbclient)

On both Linux and OS X, grep returns an exit code so it's easy to check if the process was found or not:

ps cax | grep httpd > /dev/null
if [ $? -eq 0 ]; then
  echo "Process is running."
  echo "Process is not running."

Furthermore, if you would like the list of PIDs, you could easily grep for those as well:

ps cax | grep httpd | grep -o '^[ ]*[0-9]*'

Whose output is the same on Linux and OS X:

3519 3521 3523 3524

The output of the following is an empty string, making this approach safe for processes that are not running:

echo ps cax | grep aasdfasdf | grep -o '^[ ]*[0-9]*'

This approach is suitable for writing a simple empty string test, then even iterating through the discovered PIDs.

PIDS=`ps cax | grep $PROCESS | grep -o '^[ ]*[0-9]*'`
if [ -z "$PIDS" ]; then
  echo "Process not running." 1>&2
  exit 1
  for PID in $PIDS; do
    echo $PID

You can test it by saving it to a file (named "running") with execute permissions (chmod +x running) and executing it with a parameter: ./running "httpd"

ps cax | grep httpd
if [ $? -eq 0 ]; then
  echo "Process is running."
  echo "Process is not running."


Please keep in mind that you're simply parsing the output of ps ax which means that, as seen in the Linux output, it is not simply matching on processes, but also the arguments passed to that program. I highly recommend being as specific as possible when using this method (e.g. ./running "mysql" will also match 'mysqld' processes). I highly recommend using which to check against a full path where possible.


SQL state [99999]; error code [17004]; Invalid column type: 1111 With Spring SimpleJdbcCall

Probably, you need to insert schema identifier here:

in.addValue("po_system_users", null, OracleTypes.ARRAY, "your_schema.T_SYSTEM_USER_TAB");

Can I loop through a table variable in T-SQL?

You can loop through the table variable or you can cursor through it. This is what we usually call a RBAR - pronounced Reebar and means Row-By-Agonizing-Row.

I would suggest finding a SET-BASED answer to your question (we can help with that) and move away from rbars as much as possible.

What requests do browsers' "F5" and "Ctrl + F5" refreshes generate?

Generally speaking:

F5 may give you the same page even if the content is changed, because it may load the page from cache. But Ctrl-F5 forces a cache refresh, and will guarantee that if the content is changed, you will get the new content.

What file uses .md extension and how should I edit them?

If you are looking for an editor, I suggest you use It is a simple browser-based text editor that can render Markdown on the fly.

However, if you prefer an app, and you are using OS X, you could try Mou. It is quite good and full of examples.

How to actually search all files in Visual Studio

Press Ctrl+,

Then you will see a docked window under name of "Go to all"

This a picture of the "Go to all" in my IDE


LaTex left arrow over letter in math mode

Use \overleftarrow to create a long arrow to the left.


LaTeX output

How can I have linebreaks in my long LaTeX equations?

I think I usually used eqnarray or something. It lets you say

    x &=& blah blah blah \\ 
      & & more blah blah blah \\
      & & even more blah blah

and it will be aligned by the & &... As pkaeding mentioned, it's hard to read, but when you've got an equation thats that long, it's gonna be hard to read no matter what... (The * makes it not have an equation number, IIRC)

Pandas Split Dataframe into two Dataframes at a specific row


df1 = datasX.iloc[:, :72]
df2 = datasX.iloc[:, 72:]

(iloc docs)

ASP.NET MVC View Engine Comparison

I like ndjango. It is very easy to use and very flexible. You can easily extend view functionality with custom tags and filters. I think that "greatly tied to F#" is rather advantage than disadvantage.

Module is not available, misspelled or forgot to load (but I didn't)

make sure that you insert your module and controller in your index.html first. then use this code in your module var app = angular.module("MesaViewer", []);

is there any PHP function for open page in new tab

This is a trick,

function OpenInNewTab(url) {

  var win =, '_blank');

In most cases, this should happen directly in the onclick handler for the link to prevent pop-up blockers, and the default "new window" behavior. You could do it this way, or by adding an event listener to your DOM object.

<div onclick="OpenInNewTab();">Something To Click On</div>

How to loop through files matching wildcard in batch file

Easiest way, as I see it, is to use a for loop that calls a second batch file for processing, passing that second file the base name.

According to the for /? help, basename can be extracted using the nifty ~n option. So, the base script would read:

for %%f in (*.in) do call process.cmd %%~nf

Then, in process.cmd, assume that %0 contains the base name and act accordingly. For example:

echo The file is %0
copy %0.out
ren %0.out monkeys_are_cool.txt

There might be a better way to do this in one script, but I've always been a bit hazy on how to pull of multiple commands in a single for loop in a batch file.

EDIT: That's fantastic! I had somehow missed the page in the docs that showed that you could do multi-line blocks in a FOR loop. I am going to go have to go back and rewrite some batch files now...

How to pass multiple values to single parameter in stored procedure

I think, below procedure help you to what you are looking for.

 CREATE PROCEDURE [dbo].[FindEmployeeRecord]
        @EmployeeID nvarchar(Max)
    Declare @AnswersTempTable Table
        EmpId int,         
        EmployeeName nvarchar (250),       
        EmployeeAddress nvarchar (250),  
        PostalCode nvarchar (50),
        TelephoneNo nvarchar (50),
        Email nvarchar (250),
        status nvarchar (50),  
        Sex nvarchar (50) 

    Set @sqlQuery =
    'select e.EmpId,e.EmployeeName,e.Email,e.Sex,ed.EmployeeAddress,ed.PostalCode,ed.TelephoneNo,ed.status
    from Employee e
    join EmployeeDetail ed on e.Empid = ed.iEmpID
    where Convert(nvarchar(Max),e.EmpId) in ('+@EmployeeId+')
    order by EmpId'
    Insert into @AnswersTempTable
    exec (@sqlQuery)
    select * from @AnswersTempTable

What is the difference between `git merge` and `git merge --no-ff`?

This is an old question, and this is somewhat subtly mentioned in the other posts, but the explanation that made this click for me is that non fast forward merges will require a separate commit.

Most useful NLog configurations

Reporting to an external website/database

I wanted a way to simply and automatically report errors (since users often don't) from our applications. The easiest solution I could come up with was a public URL - a web page which could take input and store it to a database - that is sent data upon an application error. (The database could then be checked by a dev or a script to know if there are new errors.)

I wrote the web page in PHP and created a mysql database, user, and table to store the data. I decided on four user variables, an id, and a timestamp. The possible variables (either included in the URL or as POST data) are:

  • app (application name)
  • msg (message - e.g. Exception occurred ...)
  • dev (developer - e.g. Pat)
  • src (source - this would come from a variable pertaining to the machine on which the app was running, e.g. Environment.MachineName or some such)
  • log (a log file or verbose message)

(All of the variables are optional, but nothing is reported if none of them are set - so if you just visit the website URL nothing is sent to the db.)

To send the data to the URL, I used NLog's WebService target. (Note, I had a few problems with this target at first. It wasn't until I looked at the source that I figured out that my url could not end with a /.)

All in all, it's not a bad system for keeping tabs on external apps. (Of course, the polite thing to do is to inform your users that you will be reporting possibly sensitive data and to give them a way to opt in/out.)

MySQL stuff

(The db user has only INSERT privileges on this one table in its own database.)

CREATE TABLE `reports` (
  `id` int(10) unsigned NOT NULL AUTO_INCREMENT,
  `applicationName` text,
  `message` text,
  `developer` text,
  `source` text,
  `logData` longtext,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=utf8 COMMENT='storage place for reports from external applications'

Website code

(PHP 5.3 or 5.2 with PDO enabled, file is index.php in /report folder)

$app = $_REQUEST['app'];
$msg = $_REQUEST['msg'];
$dev = $_REQUEST['dev'];
$src = $_REQUEST['src'];
$log = $_REQUEST['log'];

$dbData =
    array(  ':app' => $app,
            ':msg' => $msg,
            ':dev' => $dev,
            ':src' => $src,
            ':log' => $log
//print_r($dbData); // For debugging only! This could allow XSS attacks.
if(isEmpty($dbData)) die("No data provided");

try {
$db = new PDO("mysql:host=$host;dbname=reporting", "reporter", $pass, array(
$s = $db->prepare("INSERT INTO reporting.reports 
print "Added report to database";
} catch (PDOException $e) {
// Sensitive information can be displayed if this exception isn't handled
//print "Error!: " . $e->getMessage() . "<br/>";
die("PDO error");

function isEmpty($array = array()) {
    foreach ($array as $element) {
        if (!empty($element)) {
            return false;
    return true;

App code (NLog config file)

<nlog xmlns="" xmlns:xsi=""
      throwExceptions="true" internalLogToConsole="true" internalLogLevel="Warn" internalLogFile="nlog.log">
    <variable name="appTitle" value="My External App"/>
    <variable name="csvPath" value="${specialfolder:folder=Desktop:file=${appTitle} log.csv}"/>
    <variable name="developer" value="Pat"/>

    <targets async="true">
        <!--The following will keep the default number of log messages in a buffer and write out certain levels if there is an error and other levels if there is not. Messages that appeared before the error (in code) will be included, since they are buffered.-->
        <wrapper-target xsi:type="BufferingWrapper" name="smartLog">
            <wrapper-target xsi:type="PostFilteringWrapper">
                <target xsi:type="File" fileName="${csvPath}"
                archiveAboveSize="4194304" concurrentWrites="false" maxArchiveFiles="1" archiveNumbering="Sequence"
                    <layout xsi:type="CsvLayout" delimiter="Comma" withHeader="false">
                        <column name="time" layout="${longdate}" />
                        <column name="level" layout="${level:upperCase=true}"/>
                        <column name="message" layout="${message}" />
                        <column name="callsite" layout="${callsite:includeSourcePath=true}" />
                        <column name="stacktrace" layout="${stacktrace:topFrames=10}" />
                        <column name="exception" layout="${exception:format=ToString}"/>
                        <!--<column name="logger" layout="${logger}"/>-->

                 <!--during normal execution only log certain messages--> 
                <defaultFilter>level >= LogLevel.Warn</defaultFilter>

                 <!--if there is at least one error, log everything from trace level--> 
                <when exists="level >= LogLevel.Error" filter="level >= LogLevel.Trace" />

        <target xsi:type="WebService" name="web"
            <parameter name="app" layout="${appTitle}"/>
            <parameter name="msg" layout="${message}"/>
            <parameter name="dev" layout="${developer}"/>
            <parameter name="src" layout="${environment:variable=UserName} (${windows-identity}) on ${machinename} running os ${environment:variable=OSVersion} with CLR v${environment:variable=Version}"/>
            <parameter name="log" layout="${file-contents:fileName=${csvPath}}"/>


        <logger name="*" minlevel="Trace" writeTo="smartLog"/>
        <logger name="*" minlevel="Error" writeTo="web"/>

Note: there may be some issues with the size of the log file, but I haven't figured out a simple way to truncate it (e.g. a la *nix's tail command).

Defining and using a variable in batch file

The space before the = is interpreted as part of the name, and the space after it (as well as the quotation marks) are interpreted as part of the value. So the variable you’ve created can be referenced with %location %. If that’s not what you want, remove the extra space(s) in the definition.

PHP PDO: charset, set names?

I think you need an additionally query because the charset option in the DSN is actually ignored. see link posted in the comment of the other answer.

Looking at how Drupal 7 is doing it in

// Force MySQL to use the UTF-8 character set. Also set the collation, if a
// certain one has been set; otherwise, MySQL defaults to 'utf8_general_ci'
// for UTF-8.
if (!empty($connection_options['collation'])) {
  $this->exec('SET NAMES utf8 COLLATE ' . $connection_options['collation']);
else {
  $this->exec('SET NAMES utf8');

How to clone ArrayList and also clone its contents?

List<Dog> dogs;
List<Dog> copiedDogs = -> SerializationUtils.clone(dog)).Collectors.toList());

This will deep copy each dog

getActivity() returns null in Fragment function

The best to get rid of this is to keep activity reference when onAttach is called and use the activity reference wherever needed, for e.g.

public void onAttach(Context context) {
    mContext = context;

public void onDetach() {
    mContext = null;

What is better, adjacency lists or adjacency matrices for graph problems in C++?

To add to keyser5053's answer about memory usage.

For any directed graph, an adjacency matrix (at 1 bit per edge) consumes n^2 * (1) bits of memory.

For a complete graph, an adjacency list (with 64 bit pointers) consumes n * (n * 64) bits of memory, excluding list overhead.

For an incomplete graph, an adjacency list consumes 0 bits of memory, excluding list overhead.

For an adjacency list, you can use the follow formula to determine the maximum number of edges (e) before an adjacency matrix is optimal for memory.

edges = n^2 / s to determine the maximum number of edges, where s is the pointer size of the platform.

If you're graph is dynamically updating, you can maintain this efficiency with an average edge count (per node) of n / s.

Some examples with 64 bit pointers and dynamic graph (A dynamic graph updates the solution of a problem efficiently after changes, rather than recomputing it from scratch each time after a change has been made.)

For a directed graph, where n is 300, the optimal number of edges per node using an adjacency list is:

= 300 / 64
= 4

If we plug this into keyser5053's formula, d = e / n^2 (where e is the total edge count), we can see we are below the break point (1 / s):

d = (4 * 300) / (300 * 300)
d < 1/64
aka 0.0133 < 0.0156

However, 64 bits for a pointer can be overkill. If you instead use 16bit integers as pointer offsets, we can fit up to 18 edges before breaking point.

= 300 / 16
= 18

d = ((18 * 300) / (300^2))
d < 1/16
aka 0.06 < 0.0625

Each of these examples ignore the overhead of the adjacency lists themselves (64*2 for a vector and 64 bit pointers).

How do you assert that a certain exception is thrown in JUnit 4 tests?

Additionally to what NamShubWriter has said, make sure that:

  • The ExpectedException instance is public (Related Question)
  • The ExpectedException isn't instantiated in say, the @Before method. This post clearly explains all the intricacies of JUnit's order of execution.

Do not do this:

public ExpectedException expectedException;

public void setup()
    expectedException = ExpectedException.none();

Finally, this blog post clearly illustrates how to assert that a certain exception is thrown.

How do I syntax check a Bash script without running it?

I actually check all bash scripts in current dir for syntax errors WITHOUT running them using find tool:


find . -name '*.sh' -exec bash -n {} \;

If you want to use it for a single file, just edit the wildcard with the name of the file.

right click context menu for datagridview

Simply drag a ContextMenu or ContextMenuStrip component into your form and visually design it, then assign it to the ContextMenu or ContextMenuStrip property of your desired control.

Pandas: convert dtype 'object' to int

Cannot comment so posting this as an answer, which is somewhat in between @piRSquared/@cyril's solution and @cs95's:

As noted by @cs95, if your data contains NaNs or Nones, converting to string type will throw an error when trying to convert to int afterwards.

However, if your data consists of (numerical) strings, using convert_dtypes will convert it to string type unless you use pd.to_numeric as suggested by @cs95 (potentially combined with df.apply()).

In the case that your data consists only of numerical strings (including NaNs or Nones but without any non-numeric "junk"), a possibly simpler alternative would be to convert first to float and then to one of the nullable-integer extension dtypes provided by pandas (already present in version 0.24) (see also this answer):


Note that there has been recent discussion on this on github (currently an -unresolved- closed issue though) and that in the case of very long 64-bit integers you may have to convert explicitly to float128 to avoid approximations during the conversions.

Hashmap with Streams in Java 8 Streams to collect value of Map

You can also do it like this

public Map<Boolean, List<Student>> getpartitionMap(List<Student> studentsList) {

    List<Predicate<Student>> allPredicates = getAllPredicates();
    Predicate<Student> compositePredicate =
                             .reduce(w -> true, Predicate::and)
     Map<Boolean, List<Student>> studentsMap= studentsList
    return studentsMap;

public List<Student> getValidStudentsList(Map<Boolean, List<Student>> studentsMap) throws Exception {

    List<Student> validStudentsList =  studentsMap.entrySet()
             .filter(p -> p.getKey() == Boolean.TRUE)
             .flatMap(p -> p.getValue().stream())

    return validStudentsList;

public List<Student> getInValidStudentsList(Map<Boolean, List<Student>> studentsMap) throws Exception {

    List<Student> invalidStudentsList = 
             .filter(p -> p.getKey() == Boolean.FALSE)
             .flatMap(p -> p.getValue().stream())

    return invalidStudentsList;


With flatMap you will get just List<Student> instead of List<List<Student>>.


Possible to iterate backwards through a foreach?

As 280Z28 says, for an IList<T> you can just use the index. You could hide this in an extension method:

public static IEnumerable<T> FastReverse<T>(this IList<T> items)
    for (int i = items.Count-1; i >= 0; i--)
        yield return items[i];

This will be faster than Enumerable.Reverse() which buffers all the data first. (I don't believe Reverse has any optimisations applied in the way that Count() does.) Note that this buffering means that the data is read completely when you first start iterating, whereas FastReverse will "see" any changes made to the list while you iterate. (It will also break if you remove multiple items between iterations.)

For general sequences, there's no way of iterating in reverse - the sequence could be infinite, for example:

public static IEnumerable<T> GetStringsOfIncreasingSize()
    string ret = "";
    while (true)
        yield return ret;
        ret = ret + "x";

What would you expect to happen if you tried to iterate over that in reverse?

Where is localhost folder located in Mac or Mac OS X?

Applications -> XAMPP -> htdocs This is the place where you should put your files for the website you're building.

How to clean old dependencies from maven repositories?

It's been more than 6 years since the question was asked, but I didn't find any tool to clean up my repository. So I wrote one myself in python to get rid of old jars. Maybe it will be useful for someone:

from os.path import isdir
from os import listdir
import re
import shutil

dry_run = False #  change to True to get a log of what will be removed
m2_path = '/home/jb/.m2/repository/' #  here comes your repo path
version_regex = '^\d[.\d]*$'

def check_and_clean(path):
    files = listdir(path)
    for file in files:
        if not isdir('/'.join([path, file])):
    last = check_if_versions(files)
    if last is None:
        for file in files:
            check_and_clean('/'.join([path, file]))
    elif len(files) == 1:
        print('update ' + path.split(m2_path)[1])
        for file in files:
            if file == last:
            print(file + ' (newer version: ' + last + ')')
            if not dry_run:
                shutil.rmtree('/'.join([path, file]))

def check_if_versions(files):
    if len(files) == 0:
        return None
    last = ''
    for file in files:
        if re.match(version_regex, file):
            if last == '':
                last = file
            if len(last.split('.')) == len(file.split('.')):
                for (current, new) in zip(last.split('.'), file.split('.')):
                    if int(new) > int(current):
                        last = file
                    elif int(new) < int(current):
                return None
            return None
    return last


It recursively searches within the .m2 repository and if it finds a catalog where different versions reside it removes all of them but the newest.

Say you have the following tree somewhere in your .m2 repo:

+-- antlr
    +-- 2.7.2
    ¦   +-- antlr-2.7.2.jar
    ¦   +-- antlr-2.7.2.jar.sha1
    ¦   +-- antlr-2.7.2.pom
    ¦   +-- antlr-2.7.2.pom.sha1
    ¦   +-- _remote.repositories
    +-- 2.7.7
        +-- antlr-2.7.7.jar
        +-- antlr-2.7.7.jar.sha1
        +-- antlr-2.7.7.pom
        +-- antlr-2.7.7.pom.sha1
        +-- _remote.repositories

Then the script removes version 2.7.2 of antlr and what is left is:

+-- antlr
    +-- 2.7.7
        +-- antlr-2.7.7.jar
        +-- antlr-2.7.7.jar.sha1
        +-- antlr-2.7.7.pom
        +-- antlr-2.7.7.pom.sha1
        +-- _remote.repositories

If any old version, that you actively use, will be removed. It can easily be restored with maven (or other tools that manage dependencies).

You can get a log of what is going to be removed without actually removing it by setting dry_run = False. The output will go like this:

update /org/projectlombok/lombok
1.18.2 (newer version: 1.18.6)
1.16.20 (newer version: 1.18.6)

This means, that versions 1.16.20 and 1.18.2 of lombok will be removed and 1.18.6 will be left untouched.

The file can be found on my github (the latest version).

How to send email from SQL Server?

sometimes while not found sp_send_dbmail directly. You may use 'msdb.dbo.sp_send_dbmail' to try (Work fine on Windows Server 2008 R2 and is tested)

AngularJS access parent scope from child controller

You can also circumvent scope inheritance and store things in the "global" scope.

If you have a main controller in your application which wraps all other controllers, you can install a "hook" to the global scope:

function RootCtrl($scope) {
    $scope.root = $scope;

Then in any child controller, you can access the "global" scope with $scope.root. Anything you set here will be globally visible.


function RootCtrl($scope) {_x000D_
  $scope.root = $scope;_x000D_
function ChildCtrl($scope) {_x000D_
  $scope.setValue = function() {_x000D_
    $scope.root.someGlobalVar = 'someVal';_x000D_
function OtherChildCtrl($scope) {_x000D_
<script src=""></script>_x000D_
<div ng-app ng-controller="RootCtrl">_x000D_
  <p ng-controller="ChildCtrl">_x000D_
    <button ng-click="setValue()">Set someGlobalVar</button>_x000D_
  <p ng-controller="OtherChildCtrl">_x000D_
    someGlobalVar value: {{someGlobalVar}}_x000D_

Redis command to get all available keys?

Updated for Redis 2.8 and above

As noted in the comments of previous answers to this question, KEYS is a potentially dangerous command since your Redis server will be unavailable to do other operations while it serves it. Another risk with KEYS is that it can consume (dependent on the size of your keyspace) a lot of RAM to prepare the response buffer, thus possibly exhausting your server's memory.

Version 2.8 of Redis had introduced the SCAN family of commands that are much more polite and can be used for the same purpose.

The CLI also provides a nice way to work with it:

$ redis-cli --scan --pattern '*'

If input value is blank, assign a value of "empty" with Javascript

If you're using pure JS you can simply do it like:

var input = document.getElementById('myInput');

if(input.value.length == 0)
    input.value = "Empty";

Here's a demo:

How can I get a specific parameter from

The following uses regular expressions and searches only on the query string portion of the URL.

Most importantly, this method supports normal and array parameters as in http://localhost/?fiz=zip&foo[]=!!=&bar=7890#hashhashhash

function getQueryParam(param) {
    var result =
        new RegExp("(\\?|&)" + param + "(\\[\\])?=([^&]*)")

    return result ? result[3] : false;




jQuery get value of selected radio button

Check the example it works fine

<div class="dtl_radio">
  Metal purity : 
    <input type="radio" name="purityradio" class="gold_color" value="92" checked="">
    92 %
    <input type="radio" name="purityradio" class="gold_color" value="75">
    75 %
    <input type="radio" name="purityradio" class="gold_color" value="58.5">
    58.5 %
    <input type="radio" name="purityradio" class="gold_color" value="95">
    95 %
    <input type="radio" name="purityradio" class="gold_color" value="59">
    59 %
    <input type="radio" name="purityradio" class="gold_color" value="76">
    76 %
    <input type="radio" name="purityradio" class="gold_color" value="93">
    93 %

var check_value = $('.gold_color:checked').val();

How to get Android crash logs?

Base on this POST, use this class as replacement of "TopExceptionHandler"

class TopExceptionHandler implements Thread.UncaughtExceptionHandler {
private Thread.UncaughtExceptionHandler defaultUEH;
private Activity app = null;
private String line;

public TopExceptionHandler(Activity app) {
    this.defaultUEH = Thread.getDefaultUncaughtExceptionHandler(); = app;

public void uncaughtException(Thread t, Throwable e) {

    StackTraceElement[] arr = e.getStackTrace();
    String report = e.toString()+"\n\n";
    report += "--------- Stack trace ---------\n\n";
    for (int i=0; i<arr.length; i++) {
        report += "    "+arr[i].toString()+"\n";
    report += "-------------------------------\n\n";

    // If the exception was thrown in a background thread inside
    // AsyncTask, then the actual exception can be found with getCause

    report += "--------- Cause ---------\n\n";
    Throwable cause = e.getCause();
    if(cause != null) {
        report += cause.toString() + "\n\n";
        arr = cause.getStackTrace();
        for (int i=0; i<arr.length; i++) {
            report += "    "+arr[i].toString()+"\n";
    report += "-------------------------------\n\n";

    try {
        FileOutputStream trace = app.openFileOutput("stack.trace",

        Intent i = new Intent(Intent.ACTION_SEND);
        i.putExtra(Intent.EXTRA_EMAIL  , new String[]{"[email protected]"});
        i.putExtra(Intent.EXTRA_SUBJECT, "crash report azar");
        String body = "Mail this to [email protected]: " + "\n" + trace + "\n";
        i.putExtra(Intent.EXTRA_TEXT   , body);
        try {
            startActivity(Intent.createChooser(i, "Send mail..."));
        } catch (android.content.ActivityNotFoundException ex) {
           // Toast.makeText(MyActivity.this, "There are no email clients installed.", Toast.LENGTH_SHORT).show();

      //  ReaderScopeActivity.this.startActivity(Intent.createChooser(sendIntent, "Title:"));


    } catch(IOException ioe) {
        // ...

    defaultUEH.uncaughtException(t, e);

private void startActivity(Intent chooser) {



in same java class file (Activity) .....

Public class MainActivity.....


protected void onCreate(Bundle savedInstanceState) {
    Thread.setDefaultUncaughtExceptionHandler(new TopExceptionHandler(this));


Send FormData and String Data Together Through JQuery AJAX?

For Multiple file input : Try this code :

 <form name="form" id="form" method="post" enctype="multipart/form-data">
    <input type="file" name="file[]">
    <input type="file" name="file[]" >
    <input type="text" name="name" id="name">
    <input type="text" name="name1" id="name1">
    <input type="button" name="submit" value="upload" id="upload">

 $('#upload').on('click', function() {
  var fd = new FormData();
    var c=0;
    var file_data;
        file_data = $('input[type="file"]')[c].files; // for multiple files

     for(var i = 0;i<file_data.length;i++){
         fd.append("file_"+c, file_data[i]);
     var other_data = $('form').serializeArray();
         url: 'work.php',
         data: fd,
         contentType: false,
         processData: false,
         type: 'POST',
         success: function(data){

How to format a float in javascript?

There is a problem with all those solutions floating around using multipliers. Both kkyy and Christoph's solutions are wrong unfortunately.

Please test your code for number 551.175 with 2 decimal places - it will round to 551.17 while it should be 551.18 ! But if you test for ex. 451.175 it will be ok - 451.18. So it's difficult to spot this error at a first glance.

The problem is with multiplying: try 551.175 * 100 = 55117.49999999999 (ups!)

So my idea is to treat it with toFixed() before using Math.round();

function roundFix(number, precision)
    var multi = Math.pow(10, precision);
    return Math.round( (number * multi).toFixed(precision + 1) ) / multi;

How do I use arrays in cURL POST requests

You are just creating your array incorrectly. You could use http_build_query:

$fields = array(
            'username' => "annonymous",
            'api_key' => urlencode("1234"),
            'images' => array(
$fields_string = http_build_query($fields);

So, the entire code that you could use would be:

//extract data from the post

//set POST variables
$url = '';
$fields = array(
            'username' => "annonymous",
            'api_key' => urlencode("1234"),
            'images' => array(

//url-ify the data for the POST
$fields_string = http_build_query($fields);

//open connection
$ch = curl_init();

//set the url, number of POST vars, POST data
curl_setopt($ch,CURLOPT_URL, $url);
curl_setopt($ch,CURLOPT_POST, 1);
curl_setopt($ch,CURLOPT_POSTFIELDS, $fields_string);

//execute post
$result = curl_exec($ch);
echo $result;

//close connection

Convert time.Time to string

Go Playground

package main

import (

func main() {
    t := time.Now()
    // The Time type implements the Stringer interface -- it
    // has a String() method which gets called automatically by
    // functions like Printf().
    fmt.Printf("%s\n", t)

    // See the Constants section for more formats
    formatedTime := t.Format(time.RFC1123)

Regarding C++ Include another class

What is the basic problem in your code?

Your code needs to be separated out in to interfaces(.h) and Implementations(.cpp).
The compiler needs to see the composition of a type when you write something like

ClassTwo obj;

This is because the compiler needs to reserve enough memory for object of type ClassTwo to do so it needs to see the definition of ClassTwo. The most common way to do this in C++ is to split your code in to header files and source files.
The class definitions go in the header file while the implementation of the class goes in to source files. This way one can easily include header files in to other source files which need to see the definition of class who's object they create.

Why can't I simply put all code in cpp files and include them in other files?

You cannot simple put all the code in source file and then include that source file in other files.C++ standard mandates that you can declare a entity as many times as you need but you can define it only once(One Definition Rule(ODR)). Including the source file would violate the ODR because a copy of the entity is created in every translation unit where the file is included.

How to solve this particular problem?

Your code should be organized as follows:


Define ClassOne 


#include <iostream>
#include <string>

class ClassTwo
   string myType;
   void setType(string);
   std::string getType();



Implementation of ClassOne 



void ClassTwo::setType(std::string sType)
    myType = sType;

void ClassTwo::getType(float fVal)
    return myType;


#include <iostream>
#include <string>
#include "file1.h"
#include "file2.h"
using namespace std;

int main()

    ClassOne cone;
    ClassTwo ctwo;

    //some codes

Is there any alternative means rather than including header files?

If your code only needs to create pointers and not actual objects you might as well use Forward Declarations but note that using forward declarations adds some restrictions on how that type can be used because compiler sees that type as an Incomplete type.

How does MySQL process ORDER BY and LIMIT in a query?

It will order first, then get the first 20. A database will also process anything in the WHERE clause before ORDER BY.

Use sed to replace all backslashes with forward slashes

$ echo "C:\Windows\Folder\File.txt" | sed -e 's/\\/\//g'

The sed command in this case is 's/OLD_TEXT/NEW_TEXT/g'.

The leading 's' just tells it to search for OLD_TEXT and replace it with NEW_TEXT.

The trailing 'g' just says to replace all occurrences on a given line, not just the first.

And of course you need to separate the 's', the 'g', the old, and the new from each other. This is where you must use forward slashes as separators.

For your case OLD_TEXT == '\' and NEW_TEXT == '/'. But you can't just go around typing slashes and expecting things to work as expected be taken literally while using them as separators at the same time. In general slashes are quite special and must be handled as such. They must be 'escaped' (i.e. preceded) by a backslash.

So for you, OLD_TEXT == '\\' and NEW_TEXT == '\/'. Putting these inside the 's/OLD_TEXT/NEW_TEXT/g' paradigm you get
's/\\/\//g'. That reads as
's / \\ / \/ / g' and after escapes is
's / \ / / / g' which will replace all backslashes with forward slashes.

How to get folder path for ClickOnce application

Here's what I found that worked for being able to get the deployed folder location of my clickonce application and that hasn't been mentioned anywhere I saw in my searches, for my similar, specific scenario:

  • The clickonce application is deployed to a company LAN network folder.
  • The clickonce application is set to be available online or offline.
  • My clickonce installation URL and Update URLs in my project properties have nothing specified. That is, there is no separate location for installation or updates.
  • In my publishing options, I am having a desktop shortcut created for the clickonce application.
  • The folder I want to get the path for at startup is one that I want to be accessed by the DEV, INT, and PROD versions of the application, without hardcoding the path.

Here is a visual of my use case:

enter image description here

  • The blue boxed folders are my directory locations for each environment's application.
  • The red boxed folder is the directory I want to get the path for (which requires first getting the app's deployed folder location "MyClickOnceGreatApp_1_0_0_37" which is the same as the OP).

I did not find any of the suggestions in this question or their comments to work in returning the folder that the clickonce application was deployed to (that I would then move relative to this folder to find the folder of interest). No other internet searching or related SO questions turned up an answer either.

All of the suggested properties either were failing due to the object (e.g. ActivationUri) being null, or were pointing to the local PC's cached installed app folder. Yes, I could gracefully handle null objects by a check for IsNetworkDeployed - that's not a problem - but surprisingly IsNetworkDeployed returns false even though I do in fact have a network deployed folder location for the clickonce application. This is because the application is running from the local, cached bits.

The solution is to look at:

  • AppDomain.CurrentDomain.BaseDirectory when the application is being run within visual studio as I develop and
  • System.Deployment.Application.ApplicationDeployment.CurrentDeployment.UpdateLocation when it is executing normally.

System.Deployment.Application.ApplicationDeployment.CurrentDeployment.UpdateLocation correctly returns the network directory that my clickonce application is deployed to, in all cases. That is, when it is launched via:

  • setup.exe
  • MyClickOnceGreatApp.application
  • The desktop shortcut created upon first install and launch of the application.

Here's the code I use at application startup to get the path of the WorkAccounts folder. Getting the deployed application folder is simple by just not marching up to parent directories:

string directoryOfInterest = "";
if (System.Diagnostics.Debugger.IsAttached)
    directoryOfInterest = Directory.GetParent(Directory.GetParent(Directory.GetParent(AppDomain.CurrentDomain.BaseDirectory).FullName).FullName).FullName;
        string path = System.Deployment.Application.ApplicationDeployment.CurrentDeployment.UpdateLocation.ToString();
        path = path.Replace("file:", "");
        path = path.Replace("/", "\\");
        directoryOfInterest = Directory.GetParent(Directory.GetParent(path).FullName).FullName;
    catch (Exception ex)
        directoryOfInterest = "Error getting update directory needed for relative base for finding WorkAccounts directory.\n" + ex.Message + "\n\nUpdate location directory is: " + System.Deployment.Application.ApplicationDeployment.CurrentDeployment.UpdateLocation.ToString();

Google Map API - Removing Markers

According to Google documentation they said that this is the best way to do it. First create this function to find out how many markers there are/

   function setMapOnAll(map1) {
    for (var i = 0; i < markers.length; i++) {

Next create another function to take away all these markers

 function clearMarker(){

Then create this final function to erase all the markers when ever this function is called upon.

 function delateMarkers(){
markers = []
//console.log(markers) This is just if you want to


Hope that helped good luck

Showing data values on stacked bar chart in ggplot2

From ggplot 2.2.0 labels can easily be stacked by using position = position_stack(vjust = 0.5) in geom_text.

ggplot(Data, aes(x = Year, y = Frequency, fill = Category, label = Frequency)) +
  geom_bar(stat = "identity") +
  geom_text(size = 3, position = position_stack(vjust = 0.5))

enter image description here

Also note that "position_stack() and position_fill() now stack values in the reverse order of the grouping, which makes the default stack order match the legend."

Answer valid for older versions of ggplot:

Here is one approach, which calculates the midpoints of the bars.


# calculate midpoints of bars (simplified using comment by @DWin)
Data <- ddply(Data, .(Year), 
   transform, pos = cumsum(Frequency) - (0.5 * Frequency)

# library(dplyr) ## If using dplyr... 
# Data <- group_by(Data,Year) %>%
#    mutate(pos = cumsum(Frequency) - (0.5 * Frequency))

# plot bars and add text
p <- ggplot(Data, aes(x = Year, y = Frequency)) +
     geom_bar(aes(fill = Category), stat="identity") +
     geom_text(aes(label = Frequency, y = pos), size = 3)

Resultant chart

Excel VBA Password via Hex Editor

  1. Open xls file with a hex editor.
  2. Search for DPB
  3. Replace DPB to DPx
  4. Save file.
  5. Open file in Excel.
  6. Click "Yes" if you get any message box.
  7. Set new password from VBA Project Properties.
  8. Close and open again file, then type your new password to unprotect.


android EditText - finished typing event

I ended her with the same problem and I could not use the the solution with onEditorAction or onFocusChange and did not want to try the timer. A timer is too dangerous for may taste, because of all the threads and too unpredictable, as you do not know when you code is executed.

The onEditorAction do not catch when the user leave without using a button and if you use it please notice that KeyEvent can be null. The focus is unreliable at both ends the user can get focus and leave without enter any text or selecting the field and the user do not need to leave the last EditText field.

My solution use onFocusChange and a flag set when the user starts editing text and a function to get the text from the last focused view, which I call when need.

I just clear the focus on all my text fields to tricker the leave text view code, The clearFocus code is only executed if the field has focus. I call the function in onSaveInstanceState so I do not have to save the flag (mEditing) as a state of the EditText view and when important buttons is clicked and when the activity is closed.

Be careful with TexWatcher as it is call often I use the condition on focus to not react when the onRestoreInstanceState code entering text. I

final EditText mEditTextView = (EditText) getView();

    mEditTextView.addTextChangedListener(new TextWatcher() {
        public void beforeTextChanged(CharSequence s, int start, int count, int after) {


        public void onTextChanged(CharSequence s, int start, int before, int count) {


        public void afterTextChanged(Editable s) {
            if (!mEditing && mEditTextView.hasFocus()) {
                mEditing = true;
    mEditTextView.setOnFocusChangeListener(new View.OnFocusChangeListener() {

        public void onFocusChange(View v, boolean hasFocus) {
            if (!hasFocus && mEditing) {
                mEditing = false;
                ///Do the thing
protected void saveLastOpenField(){
    for (EditText view:getFields()){

Auto detect mobile browser (via user-agent?)

Yes, reading the User-Agent header will do the trick.

There are some lists out there of known mobile user agents so you don't need to start from scratch. What I did when I had to is to build a database of known user agents and store unknowns as they are detected for revision and then manually figure out what they are. This last thing might be overkill in some cases.

If you want to do it at Apache level, you can create a script which periodically generates a set of rewrite rules checking the user agent (or just once and forget about new user agents, or once a month, whatever suits your case), like

RewriteEngine On

RewriteCond %{HTTP_USER_AGENT} (OneMobileUserAgent|AnotherMobileUserAgent|...)
RewriteRule (.*) mobile/$1

which would move, for example, requests to http://domain/index.html to http://domain/mobile/index.html

If you don't like the approach of having a script recreate a htaccess file periodically, you can write a module which checks the User Agent (I didn't find one already made, but found this particularly appropriate example) and get the user agents from some sites to update them. Then you can complicate the approach as much as you want, but I think in your case the previous approach would be fine.

Angular 2 TypeScript how to find element in Array

You need to use method Array.filter:

this.persons =  this.personService.getPersons().filter(x => == this.personId)[0];

or Array.find

this.persons =  this.personService.getPersons().find(x => == this.personId);

Attach parameter to button.addTarget action in Swift

I appreciate everyone saying use tags, but really you need to extend the UIButton class and simply add the object there..

Tags are a hopeless way round this. Extend the UIButton like this (in Swift 4)

import UIKit
class PassableUIButton: UIButton{
    var params: Dictionary<String, Any>
    override init(frame: CGRect) {
        self.params = [:]
        super.init(frame: frame)

    required init?(coder aDecoder: NSCoder) {
        self.params = [:]
        super.init(coder: aDecoder)

then your call may be call (NOTE THE colon ":" in Selector(("webButtonTouched:")))

let webButton = PassableUIButton(frame: CGRect(x:310, y:40, width:40, height:40))
webButton.setTitle("Visit",for: .normal)
webButton.addTarget(self, action: #selector(YourViewController.webButtonTouched(_:)), for:.touchUpInside)
webButton.params["myvalue"] = "bob"

then finally catch it all here

@IBAction func webButtonTouched(_ sender: PassableUIButton) {
    print(sender.params["myvalue"] ?? "")

You do this one time and use it throughout your project (you can even make the child class have a generic "object" and put whatever you like into the button!). Or use the example above to put an inexhaustible number of key/string params into the button.. Really useful for including things like urls, confirm message methodology etc

As an aside, it's important that the SO community realise this there is an entire generation of bad practice being cut'n'paste round the internet by an alarming number of programmers who don't understand/haven't been taught/missed the point of the concept of object extensions

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

There is no built-in method for Node to change the CWD of the underlying shell running the Node process.

You can change the current working directory of the Node process through the command process.chdir().

var process = require('process');

When the Node process exists, you will find yourself back in the CWD you started the process in.

Replace input type=file by an image

You can replace image automatically with newly selected image.

<div class="image-upload">
      <label for="file-input">
        <img id="previewImg" src="" style="width: 100px; height: 100px;" />

      <input id="file-input" type="file" onchange="previewFile(this);" style="display: none;" />

        function previewFile(input){
            var file = $("input[type=file]").get(0).files[0];

              var reader = new FileReader();

              reader.onload = function(){
                  $("#previewImg").attr("src", reader.result);


Express: How to pass app-instance to routes from a different file?

If you want to pass an app-instance to others in Node-Typescript :

Option 1: With the help of import (when importing)

import { Application } from "express";
import { categoryRoute } from './routes/admin/category.route'
import { courseRoute } from './routes/admin/course.route';

const routing = (app: Application) => {
    app.use('/api/admin/category', categoryRoute)
    app.use('/api/admin/course', courseRoute)
export { routing }

Then import it and pass app:

import express, { Application } from 'express';

const app: Application = express();
import('./routes').then(m => m.routing(app))

Option 2: With the help of class

// index.ts
import express, { Application } from 'express';
import { Routes } from './routes';

const app: Application = express();
const rotues = new Routes(app)

Here we will access the app in the constructor of Routes Class

// routes.ts
import { Application } from 'express'
import { categoryRoute } from '../routes/admin/category.route'
import { courseRoute } from '../routes/admin/course.route';

class Routes {
    constructor(private app: Application) {

    private apply(): void {'/api/admin/category', categoryRoute)'/api/admin/course', courseRoute)

export { Routes }

GitHub - failed to connect to github 443 windows/ Failed to connect to gitHub - No Error

For me I have to set the https_proxy and http_proxy in addition to git proxy configuration then only it worked.

How to prevent colliders from passing through each other?

Old Question but maybe it helps someone.

Go to Project settings > Time and Try dividing the fixed timestep and maximum allowed timestep by two or by four.

I had the problem that my player was able to squeeze through openings smaller than the players collider and that solved it. It also helps with stopping fast moving objects.

How to read an external local JSON file in JavaScript?

Just use $.getJSON and then $.each to iterate the pair Key /value. Content example for the JSON file and functional code:

            "key": "INFO",
            "value": "This is an example."

    var url = "file.json";         
    $.getJSON(url, function (data) {
        $.each(data, function (key, model) {
            if (model.key == "INFO") {

What is the best way to get the count/length/size of an iterator?

If you've just got the iterator then that's what you'll have to do - it doesn't know how many items it's got left to iterate over, so you can't query it for that result. There are utility methods that will seem to do this efficiently (such as Iterators.size() in Guava), but underneath they're just consuming the iterator and counting as they go, the same as in your example.

However, many iterators come from collections, which you can often query for their size. And if it's a user made class you're getting the iterator for, you could look to provide a size() method on that class.

In short, in the situation where you only have the iterator then there's no better way, but much more often than not you have access to the underlying collection or object from which you may be able to get the size directly.

Cannot implicitly convert type 'System.Collections.Generic.IEnumerable<AnonymousType#1>' to 'System.Collections.Generic.List<string>

I think the answers are below

List<string> aa = (from char c in source
                    select c.ToString() ).ToList();

List<string> aa2 = (from char c1 in source
                    from char c2 in source
                    select string.Concat(c1, ".", c2)).ToList();

How to force maven update?

I had the same error and running mvn install -U and then running mvn install worked for me.

How do I use a custom deleter with a std::unique_ptr member?

It's possible to do this cleanly using a lambda in C++11 (tested in G++ 4.8.2).

Given this reusable typedef:

template<typename T>
using deleted_unique_ptr = std::unique_ptr<T,std::function<void(T*)>>;

You can write:

deleted_unique_ptr<Foo> foo(new Foo(), [](Foo* f) { customdeleter(f); });

For example, with a FILE*:

deleted_unique_ptr<FILE> file(
    fopen("file.txt", "r"),
    [](FILE* f) { fclose(f); });

With this you get the benefits of exception-safe cleanup using RAII, without needing try/catch noise.

Naming returned columns in Pandas aggregate function?

With the inspiration of @Joel Ostblom

For those who already have a workable dictionary for merely aggregation, you can use/modify the following code for the newer version aggregation, separating aggregation and renaming part. Please be aware of the nested dictionary if there are more than 1 item.

def agg_translate_agg_rename(input_agg_dict):
    agg_dict = {}
    rename_dict = {}
    for k, v in input_agg_dict.items():
        if len(v) == 1:
            agg_dict[k] = list(v.values())[0]
            rename_dict[k] = list(v.keys())[0]
            updated_index = 1
            for nested_dict_k, nested_dict_v in v.items():
                modified_key = k + "_" + str(updated_index)
                agg_dict[modified_key] = nested_dict_v
                rename_dict[modified_key] = nested_dict_k
                updated_index += 1
    return agg_dict, rename_dict

one_dict = {"column1": {"foo": 'sum'}, "column2": {"mean": 'mean', "std": 'std'}}
agg, rename = agg_translator_aa(one_dict)

We get

agg = {'column1': 'sum', 'column2_1': 'mean', 'column2_2': 'std'}
rename = {'column1': 'foo', 'column2_1': 'mean', 'column2_2': 'std'}

Please let me know if there is a smarter way to do it. Thanks.

Return a value if no rows are found in Microsoft tSQL

@hai-phan's answer using LEFT JOIN is the key, but it might be a bit hard to follow. I had a complicated query that may also return nothing. I just simplified his answer to my need. It's easy to apply to query with many columns.

  -- SELECT S.Id, ...
  -- FROM Sites S WHERE Id = @SiteId
  -- Whatever your query is
SELECT CTE.* -- If you want something else instead of NULL, use COALESCE.

Update: This answer on SqlServerCentral is the best. It utilizes this feature of MAX - "MAX returns NULL when there is no row to select."

SELECT ISNULL(MAX(value), 0) FROM table WHERE Id = @SiteId

What is the difference between ELF files and bin files?

some resources:

  1. ELF for the ARM architecture
  2. ELF from wiki

ELF format is generally the default output of compiling. if you use GNU tool chains, you can translate it to binary format by using objcopy, such as:

  arm-elf-objcopy -O binary [elf-input-file] [binary-output-file]

or using fromELF utility(built in most IDEs such as ADS though):

 fromelf -bin -o [binary-output-file] [elf-input-file]

How can I read input from the console using the Scanner class in Java?

You can flow this code:

Scanner obj= new Scanner(;
String s = obj.nextLine();

How can I mix LaTeX in with Markdown?

Perhaps mathJAX is the ticket. It's built on jsMath, a 2004 vintage JavaScript library.

As of 5-Feb-2015 I'd switch to recommend KaTeX - most performant Javascript LaTeX library from Khan Academy.

WCF ServiceHost access rights

Running Visual Studio as administrator could fix the issue, but if you use Visual Studio with for example TortoiseSVN, you cannot commit any changes. Another possible solution would be to run the service as administrator and the rest Visual Studio as local user.

Is there a "null coalescing" operator in JavaScript?

function coalesce() {
    var len = arguments.length;
    for (var i=0; i<len; i++) {
        if (arguments[i] !== null && arguments[i] !== undefined) {
            return arguments[i];
    return null;

var xyz = {};
xyz.val = coalesce(null, undefined, xyz.val, 5);

// xyz.val now contains 5

this solution works like the SQL coalesce function, it accepts any number of arguments, and returns null if none of them have a value. It behaves like the C# ?? operator in the sense that "", false, and 0 are considered NOT NULL and therefore count as actual values. If you come from a .net background, this will be the most natural feeling solution.

How can I autoformat/indent C code in vim?

Try the following keystrokes:


Explanation: gg goes to the top of the file, = is a command to fix the indentation and G tells it to perform the operation to the end of the file.

How to Convert date into MM/DD/YY format in C#


Look at the docs for custom date and time format strings for more info.

(Oh, and I hope this app isn't destined for other cultures. That format could really confuse a lot of people... I've never understood the whole month/day/year thing, to be honest. It just seems weird to go "middle/low/high" in terms of scale like that.)

Online code beautifier and formatter

For PHP, Java, C++, C, Perl, JavaScript, CSS you can try:

how to empty recyclebin through command prompt?

I prefer recycle.exe from Frank P. Westlake. It provides a nice before and after status. (I've been using Frank's various utilities for well over ten years..)

C:\> recycle.exe /E /F
Recycle Bin: ALL
    Recycle Bin C:  44 items, 42,613,970 bytes.
    Recycle Bin D:   0 items, 0 bytes.
            Total:  44 items, 42,613,970 bytes.

Emptying Recycle Bin: ALL
    Recycle Bin C:   0 items, 0 bytes.
    Recycle Bin D:   0 items, 0 bytes.
            Total:   0 items, 0 bytes.

It also has many more uses and options (output listed is from /?).

Recycle all files and folders in C:\TEMP:

List all DOC files which were recycled from any directory on the C: drive:

Restore all DOC files which were recycled from any directory on the C: drive:

Restore C:\temp\junk.txt to C:\docs\resume.txt:
  RECYCLE /U "C:\temp\junk.txt" "C:\docs\resume.txt"

Rename in place C:\etc\config.cfg to C:\archive\config.2007.cfg:
  RECYCLE /R "C:\etc\config.cfg" "C:\archive\config.2007.cfg"

Change one value based on another value in pandas

You can use map, it can map vales from a dictonairy or even a custom function.

Suppose this is your df:

    ID First_Name Last_Name
0  103          a         b
1  104          c         d

Create the dicts:

fnames = {103: "Matt", 104: "Mr"}
lnames = {103: "Jones", 104: "X"}

And map:

df['First_Name'] = df['ID'].map(fnames)
df['Last_Name'] = df['ID'].map(lnames)

The result will be:

    ID First_Name Last_Name
0  103       Matt     Jones
1  104         Mr         X

Or use a custom function:

names = {103: ("Matt", "Jones"), 104: ("Mr", "X")}
df['First_Name'] = df['ID'].map(lambda x: names[x][0])

Change image source in code behind - Wpf

None of the above solutions worked for me. But this did:

myImage.Source = new BitmapImage(new Uri(@"/Images/foo.png", UriKind.Relative));

How to get character for a given ascii value

Do you mean "A" (a string) or 'A' (a char)?

int unicode = 65;
char character = (char) unicode;
string text = character.ToString();

Note that I've referred to Unicode rather than ASCII as that's C#'s native character encoding; essentially each char is a UTF-16 code point.

Best way to detect when a user leaves a web page?

What you can do, is open up a WebSocket connection when the page loads, optionally send data through the WebSocket identifying the current user, and check when that connection is closed on the server.

Why do package names often begin with "com"

It's the domain name spelt out in reverse.

For example, one of my domains is So, I use com.hedgee as the base name of all my packages.

Write and read a list from file

As long as your file has consistent formatting (i.e. line-breaks), this is easy with just basic file IO and string operations:

with open('my_file.txt', 'rU') as in_file:
    data ='\n')

That will store your data file as a list of items, one per line. To then put it into a file, you would do the opposite:

with open('new_file.txt', 'w') as out_file:
    out_file.write('\n'.join(data)) # This will create a string with all of the items in data separated by new-line characters

Hopefully that fits what you're looking for.

Showing the same file in both columns of a Sublime Text window

Kinda little late but I tried to extend @Tobia's answer to set the layout "horizontal" or "vertical" driven by the command argument e.g.

{"keys": ["f6"], "command": "split_pane", "args": {"split_type": "vertical"} } 

Plugin code:

import sublime_plugin

class SplitPaneCommand(sublime_plugin.WindowCommand):
    def run(self, split_type):
        w = self.window
        if w.num_groups() == 1:
            if (split_type == "horizontal"):
                w.run_command('set_layout', {
                    'cols': [0.0, 1.0],
                    'rows': [0.0, 0.33, 1.0],
                    'cells': [[0, 0, 1, 1], [0, 1, 1, 2]]
            elif (split_type == "vertical"):
                w.run_command('set_layout', {
                    "cols": [0.0, 0.46, 1.0],
                    "rows": [0.0, 1.0],
                    "cells": [[0, 0, 1, 1], [1, 0, 2, 1]]

            w.run_command('move_to_group', {'group': 1})
            w.run_command('set_layout', {
                'cols': [0.0, 1.0],
                'rows': [0.0, 1.0],
                'cells': [[0, 0, 1, 1]]

Difference between shared objects (.so), static libraries (.a), and DLL's (.so)?

A static library(.a) is a library that can be linked directly into the final executable produced by the linker,it is contained in it and there is no need to have the library into the system where the executable will be deployed.

A shared library(.so) is a library that is linked but not embedded in the final executable, so will be loaded when the executable is launched and need to be present in the system where the executable is deployed.

A dynamic link library on windows(.dll) is like a shared library(.so) on linux but there are some differences between the two implementations that are related to the OS (Windows vs Linux) :

A DLL can define two kinds of functions: exported and internal. The exported functions are intended to be called by other modules, as well as from within the DLL where they are defined. Internal functions are typically intended to be called only from within the DLL where they are defined.

An SO library on Linux doesn't need special export statement to indicate exportable symbols, since all symbols are available to an interrogating process.

Specifying number of decimal places in Python

I'm astonished by the second number you mention (and confirm by your requested rounding) -- at first I thought my instinct for mental arithmetic was starting to fail me (I am getting older, after all, so that might be going the same way as my once-sharp memory!-)... but then I confirmed it hasn't, yet, by using, as I imagine you are, Python 3.1, and copying and pasting..:

>>> def input_meal():  
...     mealPrice = input('Enter the meal subtotal: $')  
...     mealPrice = float (mealPrice)  
...     return mealPrice  
>>> def calc_tax(mealPrice):  
...     tax = mealPrice*.06  
...     return tax
>>> m = input_meal()
Enter the meal subtotal: $34.45
>>> print(calc_tax(m))
>>> expected -- yet, you say it instead "returns a display of $ 2.607"... which might be a typo, just swapping two digits, except that you then ask "How can I set that to $2.61 instead?" so it really seems you truly mean 2.607 (which might be rounded to 2.61 in various ways) and definitely not the arithmetically correct result, 2.067 (which at best might be rounded to 2.07... definitely not to 2.61 as you request).

I imagine you first had the typo occur in transcription, and then mentally computed the desired rounding from the falsified-by-typo 2.607 rather than the actual original result -- is that what happened? It sure managed to confuse me for a while!-)

Anyway, to round a float to two decimal digits, simplest approach is the built-in function round with a second argument of 2:

>>> round(2.067, 2)
>>> round(2.607, 2)

For numbers exactly equidistant between two possibilities, it rounds-to-even:

>>> round(2.605, 2)
>>> round(2.615, 2)

or, as the docs put it (exemplifying with the single-argument form of round, which rounds to the closest integer):

if two multiples are equally close, rounding is done toward the even choice (so, for example, both round(0.5) and round(-0.5) are 0, and round(1.5) is 2).

However, for computations on money, I second the recommendation, already given in other answers, to stick with what the decimal module offers, instead of float numbers.

Split function in oracle to comma separated values with automatic sequence

There are multiple options. See Split single comma delimited string into rows in Oracle

You just need to add LEVEL in the select list as a column, to get the sequence number to each row returned. Or, ROWNUM would also suffice.

Using any of the below SQLs, you could include them into a FUNCTION.


  2    ( SELECT 'word1, word2, word3, word4, word5, word6' str FROM dual
  3    )
  4  SELECT trim(regexp_substr(str, '[^,]+', 1, LEVEL)) str
  6  CONNECT BY instr(str, ',', 1, LEVEL - 1) > 0
  7  /


6 rows selected.



  2    ( SELECT 'word1, word2, word3, word4, word5, word6' str FROM dual
  3    )
  4  SELECT trim(regexp_substr(str, '[^,]+', 1, LEVEL)) str
  6  CONNECT BY regexp_substr(str , '[^,]+', 1, LEVEL) IS NOT NULL
  7  /


6 rows selected.



  2        ( SELECT 'word1, word2, word3, word4, word5, word6' str FROM dual
  3        )
  4      SELECT trim(regexp_substr(str, '[^,]+', 1, LEVEL)) str
  5      FROM DATA


  2    ( SELECT 'word1, word2, word3, word4, word5, word6' str FROM dual
  3    )
  4  SELECT trim(COLUMN_VALUE) str
  5    FROM DATA, xmltable(('"' || REPLACE(str, ',', '","') || '"'))
  6  /

6 rows selected.


Using MODEL clause:

  2  (
  3         SELECT 'word1, word2, word3, word4, word5, word6' str
  4         FROM   dual ) ,
  5  model_param AS
  6  (
  7         SELECT str AS orig_str ,
  8                ','
  9                       || str
 10                       || ','                                 AS mod_str ,
 11                1                                             AS start_pos ,
 12                Length(str)                                   AS end_pos ,
 13                (Length(str) - Length(Replace(str, ','))) + 1 AS element_count ,
 14                0                                             AS element_no ,
 15                ROWNUM                                        AS rn
 16         FROM   t )
 17  SELECT   trim(Substr(mod_str, start_pos, end_pos-start_pos)) str
 18  FROM     (
 19                  SELECT *
 20                  FROM   model_param MODEL PARTITION BY (rn, orig_str, mod_str)
 21                  DIMENSION BY (element_no)
 22                  MEASURES (start_pos, end_pos, element_count)
 23                  RULES ITERATE (2000)
 24                  UNTIL (ITERATION_NUMBER+1 = element_count[0])
 25                  ( start_pos[ITERATION_NUMBER+1] = instr(cv(mod_str), ',', 1, cv(element_no)) + 1,
 26                  end_pos[iteration_number+1] = instr(cv(mod_str), ',', 1, cv(element_no) + 1) ) )
 27  WHERE    element_no != 0
 28  ORDER BY mod_str ,
 29           element_no
 30  /


6 rows selected.


You could also use DBMS_UTILITY package provided by Oracle. It provides various utility subprograms. One such useful utility is COMMA_TO_TABLE procedure, which converts a comma-delimited list of names into a PL/SQL table of names.


Checking if a string array contains a value, and if so, getting its position

We can also use Exists:

string[] array = { "cat", "dog", "perl" };

// Use Array.Exists in different ways.
bool a = Array.Exists(array, element => element == "perl");
bool c = Array.Exists(array, element => element.StartsWith("d"));
bool d = Array.Exists(array, element => element.StartsWith("x"));

Using getResources() in non-activity class

in your MainActivity :

public class MainActivity extends AppCompatActivity {
    protected void onCreate(Bundle savedInstanceState) {
        if(ResourcesHelper.resources == null){
             ResourcesHelper.resources = getResources();

ResourcesHelper :

public class ResourcesHelper {
    public static Resources resources;

then use it everywhere

String s = ResourcesHelper.resources.getString(R.string.app_name);

Editable text to string

If I understand correctly, you want to get the String of an Editable object, right? If yes, try using toString().

Git clone particular version of remote repository


Since Git 2.5.0 this configuration variable can be enabled on the server, here the GitHub feature request and the GitHub commit enabling this feature.

Bitbucket Server enabled it since version 5.5+.


# Make remote with 4 commits, and local with just one.
mkdir server
cd server
git init
touch 1
git add 1
git commit -m 1
git clone ./ ../local
for i in {2..4}; do
    touch "$i"
    git add "$i"
    git commit -m "$i"

# Before last commit.
SHA3="$(git log --format='%H' --skip=1 -n1)"
# Last commit.
SHA4="$(git log --format='%H' -n1)"

# Failing control without feature.
cd ../local
# Does not give an error, but does not fetch either.
git fetch origin "$SHA3"
# Error.
git checkout "$SHA3"

# Enable the feature.
cd ../server
git config uploadpack.allowReachableSHA1InWant true

# Now it works.
cd ../local
git fetch origin "$SHA3"
git checkout "$SHA3"
# Error.
git checkout "$SHA4"

Eclipse plugin for generating a class diagram

Try Amateras. It is a very good plugin for generating UML diagrams including class diagram.

How do I configure HikariCP in my Spring Boot app in my files?

You can use the dataSourceClassName approach, here is an example with MySQL. (Tested with spring boot 1.3 and 1.4)

First you need to exclude tomcat-jdbc from the classpath as it will be picked in favor of hikaricp.




Then just add

@ConfigurationProperties(prefix = "spring.datasource")
public DataSource dataSource() {
    return DataSourceBuilder.create().build();

I created a test project here:

Java dynamic array sizes?

Java Array sizes are fixed , You cannot make dynamic Arrays as that of in C++.

How to do an update + join in PostgreSQL?

First Table Name: tbl_table1 (tab1). Second Table Name: tbl_table2 (tab2).

Set the tbl_table1's ac_status column to "INACTIVE"

update common.tbl_table1 as tab1
set ac_status= 'INACTIVE' --tbl_table1's "ac_status"
from common.tbl_table2 as tab2
where tab1.ref_id= '1111111' 
and tab2.rel_type= 'CUSTOMER';

How to see what privileges are granted to schema of another user

Use example with from the post of Szilágyi Donát.

I use two querys, one to know what roles I have, excluding connect grant:

SELECT * FROM USER_ROLE_PRIVS WHERE GRANTED_ROLE != 'CONNECT'; -- Roles of the actual Oracle Schema

Know I like to find what privileges/roles my schema/user have; examples of my roles ROLE_VIEW_PAYMENTS & ROLE_OPS_CUSTOMERS. But to find the tables/objecst of an specific role I used:


The owner schema for this example could be PRD_CUSTOMERS_OWNER (or the role/schema inself).


Why is exception.printStackTrace() considered bad practice?

I think your list of reasons is a pretty comprehensive one.

One particularly bad example that I've encountered more than once goes like this:

    try {
      // do stuff
    } catch (Exception e) {
        e.printStackTrace(); // and swallow the exception

The problem with the above code is that the handling consists entirely of the printStackTrace call: the exception isn't really handled properly nor is it allowed to escape.

On the other hand, as a rule I always log the stack trace whenever there's an unexpected exception in my code. Over the years this policy has saved me a lot of debugging time.

Finally, on a lighter note, God's Perfect Exception.

Is it possible to put CSS @media rules inline?

You can use image-set()

<div style="
  background-image: url(icon1x.png);
  background-image: -webkit-image-set(  
    url(icon1x.png) 1x,  
    url(icon2x.png) 2x);  
  background-image: image-set(  
    url(icon1x.png) 1x,  
    url(icon2x.png) 2x);">

UTF-8 text is garbled when form is posted as multipart/form-data

I'm using org.apache.commons.fileupload.servlet.ServletFileUpload.ServletFileUpload(FileItemFactory) and defining the encoding when reading out parameter value:

List<FileItem> items = new ServletFileUpload(new DiskFileItemFactory()).parseRequest(request);

for (FileItem item : items) {
    String fieldName = item.getFieldName();

    if (item.isFormField()) {
        String fieldValue = item.getString("UTF-8"); // <-- HERE

Search and replace part of string in database

update VersionedFields
set Value = replace(replace(value,'<iframe','<a>iframe'), '> </iframe>','</a>')

and you do it in a single pass.

How to check if a file is empty in Bash?

[ -s ] || echo "file is empty"

How to get the first and last date of the current year?

Every year has the 1 st as First date and 31 as the last date what you have to do is only attach the year to that day and month for example:-

 SELECT '01/01/'+cast(year(getdate()) as varchar(4)) as [First Day],
 '12/31/'+cast(year(getdate()) as varchar(4)) as [Last Day]

What is the difference/usage of homebrew, macports or other package installation tools?

MacPorts is the way to go.

  1. Like @user475443 pointed, MacPorts has many many more packages. With brew you'll find yourself trapped soon because the formula you need doesn't exist.

  2. MacPorts is a native application: C + TCL. You don't need Ruby at all. To install Ruby on Mac OS X you might need MacPorts, so just go with MacPorts and you'll be happy.

  3. MacPorts is really stable, in 8 years I never had a problem with it, and my entire Unix ecosystem relay on it.

  4. If you are a PHP developer you can install the last version of Apache (Mac OS X uses 2.2), PHP and all the extensions you need, then upgrade all with one command. Forget to do the same with Homebrew.

  5. MacPorts support groups.

    foo@macpro:~/ port select --summary
    Name        Selected      Options
    ====        ========      =======
    db          none          db46 none
    gcc         none          gcc42 llvm-gcc42 mp-gcc48 none
    llvm        none          mp-llvm-3.3 none
    mysql       mysql56       mysql56 none
    php         php55         php55 php56 none
    postgresql  postgresql94  postgresql93 postgresql94 none
    python      none          python24 python25-apple python26-apple python27 python27-apple none

    If you have both PHP55 and PHP56 installed (with many different extensions), you can swap between them with just one command. All the relative extensions are part of the group and they will be activated within the chosen group: php55 or php56. I'm not sure Homebrew has this feature.

  6. Rubists like to rewrite everything in Ruby, because the only thing they are at ease is Ruby itself.

Android: How to rotate a bitmap on a center point

I used this configurations and still have the problem of pixelization :

Bitmap bmpOriginal = BitmapFactory.decodeResource(this.getResources(), R.drawable.map_pin);
        Bitmap targetBitmap = Bitmap.createBitmap((bmpOriginal.getWidth()),
        Paint p = new Paint();

        Matrix matrix = new Matrix();       
        matrix.setRotate((float) lock.getDirection(),(float) (bmpOriginal.getWidth()/2),

        RectF rectF = new RectF(0, 0, bmpOriginal.getWidth(), bmpOriginal.getHeight());

        targetBitmap = Bitmap.createBitmap((int)rectF.width(), (int)rectF.height(), Bitmap.Config.ARGB_8888);

        Canvas tempCanvas = new Canvas(targetBitmap); 
        tempCanvas.drawBitmap(bmpOriginal, matrix, p);

Converting JSON to XML in Java

For json to xml use the following Jackson example:

final String str = "{\"name\":\"JSON\",\"integer\":1,\"double\":2.0,\"boolean\":true,\"nested\":{\"id\":42},\"array\":[1,2,3]}";
ObjectMapper jsonMapper = new ObjectMapper();
JsonNode node = jsonMapper.readValue(str, JsonNode.class);
XmlMapper xmlMapper = new XmlMapper();
        xmlMapper.configure(SerializationFeature.INDENT_OUTPUT, true);
        xmlMapper.configure(ToXmlGenerator.Feature.WRITE_XML_DECLARATION, true);
        xmlMapper.configure(ToXmlGenerator.Feature.WRITE_XML_1_1, true);
StringWriter w = new StringWriter();
xmlMapper.writeValue(w, node);


<?xml version='1.1' encoding='UTF-8'?>

To convert it back (xml to json) take a look at this answer .

Private properties in JavaScript ES6 classes

Another way similar to the last two posted

class Example {
  constructor(foo) {

    // privates
    const self = this; = foo;

    // public interface
    return self.public;

  public = {
    // empty data
    nodata: { data: [] },
    // noop
    noop: () => {},

  // everything else private
  bar = 10

const test = new Example('FOO');
console.log(; // undefined
console.log(test.noop); // { data: [] }
console.log(; // undefined

What are the specific differences between .msi and setup.exe file?

MSI is basically an installer from Microsoft that is built into windows. It associates components with features and contains installation control information. It is not necessary that this file contains actual user required files i.e the application programs which user expects. MSI can contain another setup.exe inside it which the MSI wraps, which actually contains the user required files.

Hope this clears you doubt.

Calling Oracle stored procedure from C#?

In .Net through version 4 this can be done the same way as for SQL Server Stored Procs but note that you need:

using System.Data.OracleClient;

There are some system requirements here that you should verify are OK in your scenario.

Microsoft is deprecating this namespace as of .Net 4 so third-party providers will be needed in the future. With this in mind, you may be better off using Oracle Data Provider for .Net (ODP.NET) from the word go - this has optimizations that are not in the Microsoft classes. There are other third-party options, but Oracle has a strong vested interest in keeping .Net developers on board so theirs should be good.

Could not load type 'System.ServiceModel.Activation.HttpModule' from assembly 'System.ServiceModel

start-> Run--> c:\WINDOWS\Microsoft.NET\Framework\v4.0.30319\aspnet_regiis.exe -iru

How to get the innerHTML of selectable jquery element?

Use .val() instead of .innerHTML for getting value of selected option

Use .text() for getting text of selected option

Thanks for correcting :)

Validate email address textbox using JavaScript

This is quite an old question so I've updated this answer to take the HTML 5 email type into account.

You don't actually need JavaScript for this at all with HTML 5; just use the email input type:

<input type="email" />
  • If you want to make it mandatory, you can add the required parameter.

  • If you want to add additional RegEx validation (limit to email addresses for example), you can use the pattern parameter, e.g.:

    <input type="email" pattern="[email protected]" />

There's more information available on MozDev.

Original answer follows

First off - I'd recommend the email validator RegEx from Hexillion:

It's pretty comprehensive - :


I think you want a function in your JavaScript like:

function validateEmail(sEmail) {
  var reEmail = /^(?:[\w\!\#\$\%\&\'\*\+\-\/\=\?\^\`\{\|\}\~]+\.)*[\w\!\#\$\%\&\'\*\+\-\/\=\?\^\`\{\|\}\~]+@(?:(?:(?:[a-zA-Z0-9](?:[a-zA-Z0-9\-](?!\.)){0,61}[a-zA-Z0-9]?\.)+[a-zA-Z0-9](?:[a-zA-Z0-9\-](?!$)){0,61}[a-zA-Z0-9]?)|(?:\[(?:(?:[01]?\d{1,2}|2[0-4]\d|25[0-5])\.){3}(?:[01]?\d{1,2}|2[0-4]\d|25[0-5])\]))$/;

  if(!sEmail.match(reEmail)) {
    alert("Invalid email address");
    return false;

  return true;


In the HTML input you need to trigger the event with an onblur - the easy way to do this is to simply add something like:

<input type="text" name="email" onblur="validateEmail(this.value);" />

Of course that's lacking some sanity checks and won't do domain verification (that has to be done server side) - but it should give you a pretty solid JS email format verifier.

Note: I tend to use the match() string method rather than the test() RegExp method but it shouldn't make any difference.

C# Linq Where Date Between 2 Dates

Just change it to

var appointmentNoShow = from a in appointments
                        from p in properties
                        from c in clients
                        where a.Id == p.OID && 
                       (a.Start.Date >= startDate.Date && a.Start.Date <= endDate)

How can I convert a datetime object to milliseconds since epoch (unix time) in Python?

In Python 3.3, added new method timestamp:

import datetime
seconds_since_epoch =

Your question stated that you needed milliseconds, which you can get like this:

milliseconds_since_epoch = * 1000

If you use timestamp on a naive datetime object, then it assumed that it is in the local timezone. Use timezone-aware datetime objects if this is not what you intend to happen.

MySQL : transaction within a stored procedure

Here's an example of a transaction that will rollback on error and return the error code.

    IN P_server_id VARCHAR(100),
    IN P_db_user_pw_creds VARCHAR(32),
    IN p_premium_status_name VARCHAR(100),
    IN P_premium_status_limit INT,
    IN P_user_tag VARCHAR(255),
    IN P_first_name VARCHAR(50),
    IN P_last_name VARCHAR(50)

    DECLARE errno INT;


    INSERT INTO server_users(server_id, db_user_pw_creds, premium_status_name, premium_status_limit)
    VALUES(P_server_id, P_db_user_pw_creds, P_premium_status_name, P_premium_status_limit);

    INSERT INTO client_users(user_id, server_id, user_tag, first_name, last_name, lat, lng)
    VALUES(P_server_id, P_server_id, P_user_tag, P_first_name, P_last_name, 0, 0);



This is assuming that autocommit is set to 0. Hope this helps.

Java SSLHandshakeException "no cipher suites in common"

Having had this exception myself, I delved into the JRE source code. It became apparent that the message is rather misleading. It could mean what it says, but it more generally means that the server doesn't have the data it needs to respond to the client in the requested way. This can happen, for example, if certificates are missing from the keystore, or haven't been generated with the an appropriate algoritm. Indeed, given the cipher suites that are installed by default, one would have to go to some lengths to really get this exception because of lack of common cipher suites. In my particular case I'd generated the certificates with the default algorithm of DSA, when what I needed to get the server to work with Firefox was RSA.

What is the best way to access redux store outside a react component?

Found a solution. So I import the store in my api util and subscribe to it there. And in that listener function I set the axios' global defaults with my newly fetched token.

This is what my new api.js looks like:

// tooling modules
import axios from 'axios'

// store
import store from '../store'

function select(state) {
  return state.auth.tokens.authentication_token

function listener() {
  let token = select(store.getState())
  axios.defaults.headers.common['Authorization'] = token;

// configuration
const api = axios.create({
  baseURL: 'http://localhost:5001/api/v1',
  headers: {
    'Content-Type': 'application/json',

export default api

Maybe it can be further improved, cause currently it seems a bit inelegant. What I could do later is add a middleware to my store and set the token then and there.

Display DateTime value in dd/mm/yyyy format in Asp.NET MVC

I know this is an older question, but for reference, a really simple way for formatting dates without any data annotations or any other settings is as follows:

@Html.TextBoxFor(m => m.StartDate, new { @Value = Model.StartDate.ToString("dd-MMM-yyyy") })

The above format can of course be changed to whatever.

Creating custom function in React component

You can try this.

// Author: Hannad Rehman Sat Jun 03 2017 12:59:09 GMT+0530 (India Standard Time)

import React from 'react';
import RippleButton from '../../Components/RippleButton/rippleButton.jsx';

class HtmlComponents extends React.Component {


        //do stuff. 
        // foo==bar

    render() {
      return (
             <h1>React Components</h1>
             <RippleButton onClick={this.rippleClickFunction}/>

export default HtmlComponents;

Yhe only concern is you have to bind the context to the function

How to uncheck checked radio button

You might consider adding an additional radio button to each group labeled 'none' or the like. This can create a consistent user experience without complicating the development process.

Google Map API v3 — set bounds and center

Got everything sorted - see the last few lines for code - (bounds.extend(myLatLng); map.fitBounds(bounds);)

function initialize() {
  var myOptions = {
    zoom: 10,
    center: new google.maps.LatLng(0, 0),
    mapTypeId: google.maps.MapTypeId.ROADMAP
  var map = new google.maps.Map(
  setMarkers(map, beaches);

var beaches = [
  ['Bondi Beach', -33.890542, 151.274856, 4],
  ['Coogee Beach', -33.923036, 161.259052, 5],
  ['Cronulla Beach', -36.028249, 153.157507, 3],
  ['Manly Beach', -31.80010128657071, 151.38747820854187, 2],
  ['Maroubra Beach', -33.950198, 151.159302, 1]

function setMarkers(map, locations) {
  var image = new google.maps.MarkerImage('images/beachflag.png',
    new google.maps.Size(20, 32),
    new google.maps.Point(0,0),
    new google.maps.Point(0, 32));
  var shadow = new google.maps.MarkerImage('images/beachflag_shadow.png',
    new google.maps.Size(37, 32),
    new google.maps.Point(0,0),
    new google.maps.Point(0, 32));
  var shape = {
    coord: [1, 1, 1, 20, 18, 20, 18 , 1],
    type: 'poly'
  var bounds = new google.maps.LatLngBounds();
  for (var i = 0; i < locations.length; i++) {
    var beach = locations[i];
    var myLatLng = new google.maps.LatLng(beach[1], beach[2]);
    var marker = new google.maps.Marker({
      position: myLatLng,
      map: map,
      shadow: shadow,
      icon: image,
      shape: shape,
      title: beach[0],
      zIndex: beach[3]

Display date/time in user's locale format and time offset

Don't know how to do locale, but javascript is a client side technology.

usersLocalTime = new Date();

will have the client's time and date in it (as reported by their browser, and by extension the computer they are sitting at). It should be trivial to include the server's time in the response and do some simple math to guess-timate offset.

URL to compose a message in Gmail (with full Gmail interface and specified to, bcc, subject, etc.)

Many others have done an excellent job here giving a basic answer, especially Tobias Mühl. As mentioned, GMail's Api very closely matches the definition given by RFC2368 and RFC6068. This is true of the extended form of the mailto: links, but it's also true in the commonly-used forms found in the other answers. Of the five parameters, four are identical (such as to, cc, bcc and body) and one received only slight modification (su is gmail's version of subject).

If you want to know more about what you can do with mailTo gmail URLs, then these RFCs might be of help. Unfortunately, Google has not published any source themselves.

To clarify the parameters:

  • to - Email to who
  • su (gmail API) / subject (mailTo API) - Email Title
  • body - Email Body
  • bcc - Email Blind-Carbon Copy
  • cc - Email Carbon Copy address

How do I run a bat file in the background from another bat file?

Two years old, but for completeness...

Standard, inline approach: (i.e. behaviour you'd get when using & in Linux)

START /B CMD /C CALL "foo.bat" [args [...]]

Notes: 1. CALL is paired with the .bat file because that where it usually goes.. (i.e. This is just an extension to the CMD /C CALL "foo.bat" form to make it asynchronous. Usually, it's required to correctly get exit codes, but that's a non-issue here.); 2. Double quotes around the .bat file is only needed if the name contains spaces. (The name could be a path in which case there's more likelihood of that.).

If you don't want the output:

START /B CMD /C CALL "foo.bat" [args [...]] >NUL 2>&1

If you want the bat to be run on an independent console: (i.e. another window)

START CMD /C CALL "foo.bat" [args [...]]

If you want the other window to hang around afterwards:

START CMD /K CALL "foo.bat" [args [...]]

Note: This is actually poor form unless you have users that specifically want to use the opened window as a normal console. If you just want the window to stick around in order to see the output, it's better off putting a PAUSE at the end of the bat file. Or even yet, add ^& PAUSE after the command line:

START CMD /C CALL "foo.bat" [args [...]] ^& PAUSE

How do I get user IP address in django?

No More confusion In the recent versions of Django it is mentioned clearly that the Ip address of the client is available at


for more info check the Django Docs

Difference between the Apache HTTP Server and Apache Tomcat?

Well, Apache is HTTP webserver, where as Tomcat is also webserver for Servlets and JSP. Moreover Apache is preferred over Apache Tomcat in real time

How do I test a website using XAMPP?

Make a new folder inside htdocs and access it in browser.Like this or this. Always start Apache when you start working or check whether it has started (in Control panel of xampp).

How do I open port 22 in OS X 10.6.7

I couldn't solve the problem; Then I did the following and the issue was resolved: Refer here:

sudo launchctl unload -w /System/Library/LaunchDaemons/ssh.plist  
    (Supply your password when it is requested)   
sudo launchctl load -w /System/Library/LaunchDaemons/ssh.plist  
ssh -v localhost  
sudo launchctl list | grep "sshd"  
    46427   -   com.openssh.sshd  

Why is super.super.method(); not allowed in Java?

I think this is a problem that breaks the inheritance agreement.
By extending a class you obey / agree its behavior, features
Whilst when calling super.super.method(), you want to break your own obedience agreement.

You just cannot cherry pick from the super class.

However, there may happen situations when you feel the need to call super.super.method() - usually a bad design sign, in your code or in the code you inherit !
If the super and super super classes cannot be refactored (some legacy code), then opt for composition over inheritance.

Encapsulation breaking is when you @Override some methods by breaking the encapsulated code. The methods designed not to be overridden are marked final.

python: get directory two levels up

The best solution (for python >= 3.4) when executing from any directory is:

from pathlib import Path
two_up = Path(__file__).resolve().parents[1]

How to see which flags -march=native will activate?

To see command-line flags, use:

gcc -march=native -E -v - </dev/null 2>&1 | grep cc1

If you want to see the compiler/precompiler defines set by certain parameters, do this:

echo | gcc -dM -E - -march=native

What is the difference between an interface and abstract class?

I am 10 yrs late to the party but would like to attempt any way. Wrote a post about the same on medium few days back. Thought of posting it here.

tl;dr; When you see “Is A” relationship use inheritance/abstract class. when you see “has a” relationship create member variables. When you see “relies on external provider” implement (not inherit) an interface.

Interview Question: What is the difference between an interface and an abstract class? And how do you decide when to use what? I mostly get one or all of the below answers: Answer 1: You cannot create an object of abstract class and interfaces.

ZK (That’s my initials): You cannot create an object of either. So this is not a difference. This is a similarity between an interface and an abstract class. Counter Question: Why can’t you create an object of abstract class or interface?

Answer 2: Abstract classes can have a function body as partial/default implementation.

ZK: Counter Question: So if I change it to a pure abstract class, marking all the virtual functions as abstract and provide no default implementation for any virtual function. Would that make abstract classes and interfaces the same? And could they be used interchangeably after that?

Answer 3: Interfaces allow multi-inheritance and abstract classes don’t.

ZK: Counter Question: Do you really inherit from an interface? or do you just implement an interface and, inherit from an abstract class? What’s the difference between implementing and inheriting? These counter questions throw candidates off and make most scratch their heads or just pass to the next question. That makes me think people need help with these basic building blocks of Object-Oriented Programming. The answer to the original question and all the counter questions is found in the English language and the UML. You must know at least below to understand these two constructs better.

Common Noun: A common noun is a name given “in common” to things of the same class or kind. For e.g. fruits, animals, city, car etc.

Proper Noun: A proper noun is the name of an object, place or thing. Apple, Cat, New York, Honda Accord etc.

Car is a Common Noun. And Honda Accord is a Proper Noun, and probably a Composit Proper noun, a proper noun made using two nouns.

Coming to the UML Part. You should be familiar with below relationships:

  • Is A
  • Has A
  • Uses

Let’s consider the below two sentences. - HondaAccord Is A Car? - HondaAccord Has A Car?

Which one sounds correct? Plain English and comprehension. HondaAccord and Cars share an “Is A” relationship. Honda accord doesn’t have a car in it. It “is a” car. Honda Accord “has a” music player in it.

When two entities share the “Is A” relationship it’s a better candidate for inheritance. And Has a relationship is a better candidate for creating member variables. With this established our code looks like this:

abstract class Car
   string color;
   int speed;
class HondaAccord : Car
   MusicPlayer musicPlayer;

Now Honda doesn't manufacture music players. Or at least it’s not their main business.

So they reach out to other companies and sign a contract. If you receive power here and the output signal on these two wires it’ll play just fine on these speakers.

This makes Music Player a perfect candidate for an interface. You don’t care who provides support for it as long as the connections work just fine.

You can replace the MusicPlayer of LG with Sony or the other way. And it won’t change a thing in Honda Accord.

Why can’t you create an object of abstract classes?

Because you can’t walk into a showroom and say give me a car. You’ll have to provide a proper noun. What car? Probably a honda accord. And that’s when a sales agent could get you something.

Why can’t you create an object of an interface? Because you can’t walk into a showroom and say give me a contract of music player. It won’t help. Interfaces sit between consumers and providers just to facilitate an agreement. What will you do with a copy of the agreement? It won’t play music.

Why do interfaces allow multiple inheritance?

Interfaces are not inherited. Interfaces are implemented. The interface is a candidate for interaction with the external world. Honda Accord has an interface for refueling. It has interfaces for inflating tires. And the same hose that is used to inflate a football. So the new code will look like below:

abstract class Car
    string color;
    int speed;
class HondaAccord : Car, IInflateAir, IRefueling
    MusicPlayer musicPlayer;

And the English will read like this “Honda Accord is a Car that supports inflating tire and refueling”.

jquery .html() vs .append()

You can get the second method to achieve the same effect by:

var mySecondDiv = $('<div></div>');
$(mySecondDiv).find('div').attr('id', 'mySecondDiv');

Luca mentioned that html() just inserts hte HTML which results in faster performance.

In some occassions though, you would opt for the second option, consider:

// Clumsy string concat, error prone
$('#myDiv').html("<div style='width:'" + myWidth + "'px'>Lorem ipsum</div>");

// Isn't this a lot cleaner? (though longer)
var newDiv = $('<div></div>');
$(newDiv).find('div').css('width', myWidth);

What is the difference between Integer and int in Java?

An Integer is pretty much just a wrapper for the primitive type int. It allows you to use all the functions of the Integer class to make life a bit easier for you.

If you're new to Java, something you should learn to appreciate is the Java documentation. For example, anything you want to know about the Integer Class is documented in detail.

This is straight out of the documentation for the Integer class:

The Integer class wraps a value of the primitive type int in an object. An object of type Integer contains a single field whose type is int.

C# int to byte[]

The RFC is just trying to say that a signed integer is a normal 4-byte integer with bytes ordered in a big-endian way.

Now, you are most probably working on a little-endian machine and BitConverter.GetBytes() will give you the byte[] reversed. So you could try:

int intValue;
byte[] intBytes = BitConverter.GetBytes(intValue);
byte[] result = intBytes;

For the code to be most portable, however, you can do it like this:

int intValue;
byte[] intBytes = BitConverter.GetBytes(intValue);
if (BitConverter.IsLittleEndian)
byte[] result = intBytes;

How to uninstall an older PHP version from centOS7

yum -y remove php* to remove all php packages then you can install the 5.6 ones.

What are the lengths of Location Coordinates, latitude and longitude?

Latitude maximum in total is: 9 (12.3456789), longitude 10 (123.4567890), they both have maximum 7 decimals chars (At least is what i can find in Google Maps),

For example, both columns in Rails and Postgresql looks something like this:

t.decimal :latitude, precision: 9, scale: 7
t.decimal :longitude, precision: 10, scale: 7

How do I install TensorFlow's tensorboard?

If your Tensorflow install is located here:


then the python command to launch Tensorboard is:

$ python /usr/local/lib/python2.7/dist-packages/tensorflow/tensorboard/ --logdir=/home/user/Documents/.../logdir

The installation from pip allows you to use:

$ tensorboard --logdir=/home/user/Documents/.../logdir

Running vbscript from batch file

Just try this code:

start "" "C:\Users\DiPesh\Desktop\vbscript\welcome.vbs"

and save as .bat, it works for me

SQL Server stored procedure parameters

I'm going on a bit of an assumption here, but I'm assuming the logic inside the procedure gets split up via task. And you cant have nullable parameters as @Yuck suggested because of the dynamics of the parameters?

So going by my assumption

If TaskName = "Path1" Then Something

If TaskName = "Path2" Then Something Else

My initial thought is, if you have separate functions with business-logic you need to create, and you can determine that you have say 5-10 different scenarios, rather write individual stored procedures as needed, instead of trying one huge one solution fits all approach. Might get a bit messy to maintain.

But if you must...

Why not try dynamic SQL, as suggested by @E.J Brennan (Forgive me, i haven't touched SQL in a while so my syntax might be rusty) That being said i don't know if its the best approach, but could this could possibly meet your needs?

    @TaskName varchar(50)
    @Values varchar(200)

  IF @TaskName = 'Something'
    @SQL = 'INSERT INTO.....' + CHAR(13)
    @SQL += @Values + CHAR(13) 

  IF @TaskName = 'Something Else'
    @SQL += @Values + CHAR(13) 


(The CHAR(13) adds a new line.. an old habbit i picked up somewhere, used to help debugging/reading dynamic procedures when running SQL profiler.)

Check that a input to UITextField is numeric only

IMO the best way to accomplish your goal is to display a numeric keyboard rather than the normal keyboard. This restricts which keys are available to the user. This alleviates the need to do validation, and more importantly it prevents the user from making a mistake. The number pad is also much nicer for entering numbers because the keys are substantially larger.

In interface builder select the UITextField, go to the Attributes Inspector and change the "Keyboard Type" to "Decimal Pad".

enter image description here

That'll make the keyboard look like this:

enter image description here

The only thing left to do is ensure the user doesn't enter in two decimal places. You can do this while they're editing. Add the following code to your view controller. This code removes a second decimal place as soon as it is entered. It appears to the user as if the 2nd decimal never appeared in the first place.

- (void)viewDidLoad
  [super viewDidLoad];

  [self.textField addTarget:self

- (void)textFieldDidChange:(UITextField *)textField
  NSString *text = textField.text;
  NSRange range = [text rangeOfString:@"."];

  if (range.location != NSNotFound &&
      [text hasSuffix:@"."] &&
      range.location != (text.length - 1))
    // There's more than one decimal
    textField.text = [text substringToIndex:text.length - 1];

Is there a 'foreach' function in Python 3?

If you're just looking for a more concise syntax you can put the for loop on one line:

array = ['a', 'b']
for value in array: print(value)

Just separate additional statements with a semicolon.

array = ['a', 'b']
for value in array: print(value); print('hello')

This may not conform to your local style guide, but it could make sense to do it like this when you're playing around in the console.

how to implement Interfaces in C++?

C++ has no built-in concepts of interfaces. You can implement it using abstract classes which contains only pure virtual functions. Since it allows multiple inheritance, you can inherit this class to create another class which will then contain this interface (I mean, object interface :) ) in it.

An example would be something like this -

class Interface
    virtual ~Interface(){}
    virtual void method1() = 0;    // "= 0" part makes this method pure virtual, and
                                   // also makes this class abstract.
    virtual void method2() = 0;

class Concrete : public Interface
    int myMember;

    void method1();
    void method2();

// Provide implementation for the first method
void Concrete::method1()
    // Your implementation

// Provide implementation for the second method
void Concrete::method2()
    // Your implementation

int main(void)
    Interface *f = new Concrete();


    delete f;

    return 0;

How do I use namespaces with TypeScript external modules?

OP I'm with you man. again too, there is nothing wrong with that answer with 300+ up votes, but my opinion is:

  1. what is wrong with putting classes into their cozy warm own files individually? I mean this will make things looks much better right? (or someone just like a 1000 line file for all the models)

  2. so then, if the first one will be achieved, we have to import import import... import just in each of the model files like man, srsly, a model file, a .d.ts file, why there are so many *s in there? it should just be simple, tidy, and that's it. Why I need imports there? why? C# got namespaces for a reason.

  3. And by then, you are literally using "filenames.ts" as identifiers. As identifiers... Come on its 2017 now and we still do that? Ima go back to Mars and sleep for another 1000 years.

So sadly, my answer is: nop, you cannot make the "namespace" thing functional if you do not using all those imports or using those filenames as identifiers (which I think is really silly). Another option is: put all of those dependencies into a box called filenameasidentifier.ts and use

export namespace(or module) boxInBox {} .

wrap them so they wont try to access other classes with same name when they are just simply trying to get a reference from the class sit right on top of them.

How to subtract 30 days from the current date using SQL Server


Cast your VARCHAR value to DATETIME and add -30 for subtraction. Also, In sql-server the format Fri, 14 Nov 2014 23:03:35 GMT was not converted to DATETIME. Try substring for it:

       CAST(SUBSTRING ('Fri, 14 Nov 2014 23:03:35 GMT', 6, 21) 
       AS DATETIME))

New line in Sql Query

use CHAR(10) for New Line in SQL
char(9) for Tab
and Char(13) for Carriage Return

Can't bind to 'ngForOf' since it isn't a known property of 'tr' (final release)

For me the problem was that I did not import the custom made module HouseModule in my app.module.ts. I had the other imports.

File: app.module.ts

import { HouseModule } from './Modules/house/house.module';

  imports: [

Calculating Pearson correlation and significance in Python

Hmm, many of these responses have long and hard to read code...

I'd suggest using numpy with its nifty features when working with arrays:

import numpy as np
def pcc(X, Y):
   ''' Compute Pearson Correlation Coefficient. '''
   # Normalise X and Y
   X -= X.mean(0)
   Y -= Y.mean(0)
   # Standardise X and Y
   X /= X.std(0)
   Y /= Y.std(0)
   # Compute mean product
   return np.mean(X*Y)

# Using it on a random example
from random import random
X = np.array([random() for x in xrange(100)])
Y = np.array([random() for x in xrange(100)])
pcc(X, Y)

Get Request and Session Parameters and Attributes from JSF pages

You can either use

<h:outputText value="#{param['id']}" /> or

<h:outputText value="#{request.getParameter('id')}" />

However if you want to pass the parameters to your backing beans, using f:viewParam is probably what you want. "A view parameter is a mapping between a query string parameter and a model value."

<f:viewParam name="id" value="#{blog.entryId}"/>

This will set the id param of the GET parameter to the blog bean's entryId field. See for the details.

SVN repository backup strategies

svnadmin hotcopy

svnadmin hotcopy REPOS_PATH NEW_REPOS_PATH

This subcommand makes a full “hot” backup of your repository, including all hooks, configuration files, and, of course, database files.

Convert timestamp to date in MySQL query

FROM_UNIXTIME(unix_timestamp, [format]) is all you need

FROM_UNIXTIME(user.registration, '%Y-%m-%d') AS 'date_formatted'

FROM_UNIXTIME gets a number value and transforms it to a DATE object,
or if given a format string, it returns it as a string.

The older solution was to get the initial date object and format it with a second function DATE_FORMAT... but this is no longer necessary

Could not resolve all dependencies for configuration ':classpath'

In my case, my Android Studio version was 3.6.1 and i have modified the classpath like below;

classpath ''

and that error was gone.

sys.argv[1] meaning in script

To pass arguments to your python script while running a script via command line

python test1.jpg test2.jpg

here, script name -, argument 1 - test1.jpg, argument 2 - test2.jpg

With in the script i use


which give me the list of arguments i passed in command line as ['test1.jpg', 'test2.jpg']

How to get current language code with Swift?

swift 3

let preferredLanguage = Locale.preferredLanguages[0] as String
print (preferredLanguage) //en-US

let arr = preferredLanguage.components(separatedBy: "-")
let deviceLanguage = arr.first
print (deviceLanguage) //en

Why can't I see the "Report Data" window when creating reports?

It is in visual studio. In the designer page, it is on in the menu bar, there is XTRAREPORTS field. You can show up panels using it

How do I get the base URL with PHP?

You can do it like this, but sorry my english is not good enough.

First, get home base url with this simple code..

I've tested this code on my local server and public and the result is good.


function home_base_url(){   

// first get http protocol if http or https

$base_url = (isset($_SERVER['HTTPS']) &&

$_SERVER['HTTPS']!='off') ? 'https://' : 'http://';

// get default website root directory

$tmpURL = dirname(__FILE__);

// when use dirname(__FILE__) will return value like this "C:\xampp\htdocs\my_website",

//convert value to http url use string replace, 

// replace any backslashes to slash in this case use chr value "92"

$tmpURL = str_replace(chr(92),'/',$tmpURL);

// now replace any same string in $tmpURL value to null or ''

// and will return value like /localhost/my_website/ or just /my_website/

$tmpURL = str_replace($_SERVER['DOCUMENT_ROOT'],'',$tmpURL);

// delete any slash character in first and last of value

$tmpURL = ltrim($tmpURL,'/');

$tmpURL = rtrim($tmpURL, '/');

// check again if we find any slash string in value then we can assume its local machine

    if (strpos($tmpURL,'/')){

// explode that value and take only first value

       $tmpURL = explode('/',$tmpURL);

       $tmpURL = $tmpURL[0];


// now last steps

// assign protocol in first value

   if ($tmpURL !== $_SERVER['HTTP_HOST'])

// if protocol its http then like this

      $base_url .= $_SERVER['HTTP_HOST'].'/'.$tmpURL.'/';


// else if protocol is https

      $base_url .= $tmpURL.'/';

// give return value

return $base_url; 



// and test it

echo home_base_url();

output will like this :

local machine : http://localhost/my_website/ or https://myhost/my_website 

public : or

use home_base_url function at index.php of your website and define it

and then you can use this function to load scripts, css and content via url like


echo '<script type="text/javascript" src="'.home_base_url().'js/script.js"></script>'."\n";


will create output like this :

<script type="text/javascript" src=""></script>

and if this script works fine,,!

Finding the last index of an array

New in C# 8.0 you can use the so-called "hat" (^) operator! This is useful for when you want to do something in one line!

var mystr = "Hello World!";
var lastword = mystr.Split(" ")[^1];
// World!

instead of the old way:

var mystr = "Hello World";
var split = mystr.Split(" ");
var lastword = split[split.Length - 1];
// World!

It doesn't save much space, but it looks much clearer (maybe I only think this because I came from python?). This is also much better than calling a method like .Last() or .Reverse() Read more at MSDN

Edit: You can add this functionality to your class like so:

public class MyClass
  public object this[Index indx]
      // Do indexing here, this is just an example of the .IsFromEnd property
      if (indx.IsFromEnd)
        Console.WriteLine("Negative Index!")
        Console.WriteLine("Positive Index!")

The Index.IsFromEnd will tell you if someone is using the 'hat' (^) operator

SSRS expression to format two decimal places does not show zeros

You need to make sure that the first numeral to the right of the decimal point is always displayed. In custom format strings, # means display the number if it exists, and 0 means always display something, with 0 as the placeholder.

So in your case you will need something like:

=Format(Fields!CUL1.Value, "#,##0.##")

This saying: display 2 DP if they exist, for the non-zero part always display the lowest part, and use , as the grouping separator.

This is how it looks on your data (I've added a large value as well for reference):

enter image description here

If you're not interested in separating thousands, millions, etc, just use #0.## as Paul-Jan suggested.

The standard docs for Custom Numeric Format Strings are your best reference here.

Append an array to another array in JavaScript

If you want to modify the original array instead of returning a new array, use .push()...

array1.push.apply(array1, array2);
array1.push.apply(array1, array3);

I used .apply to push the individual members of arrays 2 and 3 at once.


array1.push.apply(array1, array2.concat(array3));

To deal with large arrays, you can do this in batches.

for (var n = 0, to_add = array2.concat(array3); n < to_add.length; n+=300) {
    array1.push.apply(array1, to_add.slice(n, n+300));

If you do this a lot, create a method or function to handle it.

var push_apply = Function.apply.bind([].push);
var slice_call =[].slice);

Object.defineProperty(Array.prototype, "pushArrayMembers", {
    value: function() {
        for (var i = 0; i < arguments.length; i++) {
            var to_add = arguments[i];
            for (var n = 0; n < to_add.length; n+=300) {
                push_apply(this, slice_call(to_add, n, n+300));

and use it like this:

array1.pushArrayMembers(array2, array3);

var push_apply = Function.apply.bind([].push);_x000D_
var slice_call =[].slice);_x000D_
Object.defineProperty(Array.prototype, "pushArrayMembers", {_x000D_
    value: function() {_x000D_
        for (var i = 0; i < arguments.length; i++) {_x000D_
            var to_add = arguments[i];_x000D_
            for (var n = 0; n < to_add.length; n+=300) {_x000D_
                push_apply(this, slice_call(to_add, n, n+300));_x000D_
var array1 = ['a','b','c'];_x000D_
var array2 = ['d','e','f'];_x000D_
var array3 = ['g','h','i'];_x000D_
array1.pushArrayMembers(array2, array3);_x000D_
document.body.textContent = JSON.stringify(array1, null, 4);

Fastest way to determine if record exists

For those stumbling upon this from MySQL or Oracle background - MySQL supports the LIMIT clause to select a limited number of records, while Oracle uses ROWNUM.

How to reset settings in Visual Studio Code?

On Linux environment delete the folder "~/.config/Code" to reset Visual Studio Code Settings.

How can I do GUI programming in C?

Use win APIs in your main function:

  1. RegisterClassEx() note: you have to provide a pointer to a function (usually called WndProc) which handles windows messages such as WM_CREATE, WM_COMMAND etc
  2. CreateWindowEx()
  3. ShowWindow()
  4. UpdateWindow()

Then write another function which handles win's messages (mentioned in #1). When you receive the message WM_CREATE you have to call CreateWindow(). The class is what control is that window, for example "edit" is a text box and "button" is a.. button :). You have to specify an ID for each control (of your choice but unique among all). CreateWindow() returns a handle to that control, which needs to be memorized. When the user clicks on a control you receive the WM_COMMAND message with the ID of that control. Here you can handle that event. You might find useful SetWindowText() and GetWindowText() which allows you to set/get the text of any control.
You will need only the win32 SDK. You can get it here.

Getting time and date from timestamp with php

If you dont want to change the format of date and time from the timestamp, you can use the explode function in php

$timestamp = "2012-04-02 02:57:54"
$datetime = explode(" ",$timestamp);
$date = $datetime[0];
$time = $datetime[1];

HTML email in outlook table width issue - content is wider than the specified table width

I guess problem is in width attributes in table and td remove 'px' for example

<table border="0" cellpadding="0" cellspacing="0" width="580px" style="background-color: #0290ba;">

Should be

<table border="0" cellpadding="0" cellspacing="0" width="580" style="background-color: #0290ba;">

How to find sum of multiple columns in a table in SQL Server 2005?

Try this:

select sum(num_tax_amount+num_total_amount) from table_name;

generate a random number between 1 and 10 in c

You need a different seed at every execution.

You can start to call at the beginning of your program:


Note that % 10 yields a result from 0 to 9 and not from 1 to 10: just add 1 to your % expression to get 1 to 10.

How to hash some string with sha256 in Java?

Another alternative is Guava which has an easy-to-use suite of Hashing utilities. For example, to hash a string using SHA256 as a hex-string you would simply do:

final String hashed = Hashing.sha256()
        .hashString("your input", StandardCharsets.UTF_8)

don't fail jenkins build if execute shell fails

On the (more general) question in title - to prevent Jenkins from failing you can prevent it from seeing exit code 1. Example for ping:

bash -c "ping -c 1; exit 0"

And now you can e.g. get output of ping:

output=`bash -c "ping -c 1; exit 0"`

Of course instead of ping ... You can use any command(s) - including git commit.

HTML img align="middle" doesn't align an image

The attribute align=middle sets vertical alignment. To set horizontal alignment using HTML, you can wrap the element inside a center element and remove all the CSS you have now.

<center><img src=_x000D_
width="42" height="42"></center>

If you would rather do it in CSS, there are several ways. A simple one is to set text-align on a container:

<div style="text-align: center"><img src=_x000D_
width="42" height="42"></div>

Can I Set "android:layout_below" at Runtime Programmatically?


RelativeLayout.LayoutParams params= new RelativeLayout.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT,ViewGroup.LayoutParams.WRAP_CONTENT); 

First, the code creates a new layout params by specifying the height and width. The addRule method adds the equivalent of the xml properly android:layout_below. Then you just call View#setLayoutParams on the view you want to have those params.

Git - Won't add files?

To add to the possible solutions for other users:

Make sure you have not changed the case of the folder name in Windows:

I had a similar problem where a folder called Setup controlled by Git and hosted on GitHub, all development was done on a Windows machine.

At some point I changed the folder to setup (lower case S). From that point on when I added new files to the setup folder they were stored in the setup folder and not the Setup folder, but I guess because I was developing on a Windows machine the existing Setup folder in git/github was not changed to setup.

The result was that I couldn't see all of the files in the setup in GitHub. I suspect that if I cloned the project on a *nix machine I would have seen two folders, Setup and setup.

So make sure you have not changed the case of the containing folder on a Windows machine, if you have then I'd suggest:

  • Renaming the folder to something like setup-temp
  • git add -A
  • git commit -m "Whatever"
  • Rename the folder back to what you want
  • git add -A
  • git commit -m "Whatever"

How to update ruby on linux (ubuntu)?

First, which version of ubuntu are you using, it might be easiest to just upgrade to one that has it.

Next, enable backports (system menue, adminstration, software sources), and search for in in synaptic.

Last, look for a ppa for it.

How can I see function arguments in IPython Notebook Server 3?

Adding screen shots(examples) and some more context for the answer of @Thomas G.

if its not working please make sure if you have executed code properly. In this case make sure import pandas as pd is ran properly before checking below shortcut.

Place the cursor in middle of parenthesis () before you use shortcut.

shift + tab

Display short document and few params

enter image description here

shift + tab + tab

Expands document with scroll bar

enter image description here

shift + tab + tab + tab

Provides document with a Tooltip: "will linger for 10secs while you type". which means it allows you write params and waits for 10secs.

enter image description here

shift + tab + tab + tab + tab

It opens a small window in bottom with option(top righ corner of small window) to open full documentation in new browser tab.

enter image description here

Handle Guzzle exception and get HTTP body

Guzzle 6.x

Per the docs, the exception types you may need to catch are:

  • GuzzleHttp\Exception\ClientException for 400-level errors
  • GuzzleHttp\Exception\ServerException for 500-level errors
  • GuzzleHttp\Exception\BadResponseException for both (it's their superclass)

Code to handle such errors thus now looks something like this:

$client = new GuzzleHttp\Client;
try {
catch (GuzzleHttp\Exception\ClientException $e) {
    $response = $e->getResponse();
    $responseBodyAsString = $response->getBody()->getContents();

Remove elements from collection while iterating

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

Suppose we have the following collection of books

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

Collect and Remove

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

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

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

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

Using ListIterator

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

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

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

Using JDK >= 8

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

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

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

Or use the new stream API:

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

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

Use Sublist or Subset

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


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

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


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

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

Content Type text/xml; charset=utf-8 was not supported by service

I was also facing the same problem recently. after struggling a couple of hours,finally a solution came out by addition to

to your SVC markup file. e.g.
ServiceHost Language="C#" Debug="true" Service="QuiznetOnline.Web.UI.WebServices.LogService" 

and now you can compile & run your application successfully.

Create an Oracle function that returns a table





    FROM    ...**





Android- create JSON Array and JSON Object

public JSONObject makJsonObject(int id[], String name[], String year[],
            String curriculum[], String birthday[], int numberof_students)
            throws JSONException {
        JSONObject obj = null;
        JSONArray jsonArray = new JSONArray();
        for (int i = 0; i < numberof_students; i++) {
            obj = new JSONObject();
            try {
                obj.put("id", id[i]);
                obj.put("name", name[i]);
                obj.put("year", year[i]);
                obj.put("curriculum", curriculum[i]);
                obj.put("birthday", birthday[i]);

            } catch (JSONException e) {
                // TODO Auto-generated catch block

        JSONObject finalobject = new JSONObject();
        finalobject.put("student", jsonArray);
        return finalobject;

How to add link to flash banner

@Michiel is correct to create a button but the code for ActionScript 3 it is a little different - where movieClipName is the name of your 'button'.

movieClipName.addEventListener(MouseEvent.CLICK, callLink);
function callLink:void {
  var url:String = "http://site";
  var request:URLRequest = new URLRequest(url);
  try {
    navigateToURL(request, '_blank');
  } catch (e:Error) {
    trace("Error occurred!");


How create table only using <div> tag and Css

divs shouldn't be used for tabular data. That is just as wrong as using tables for layout.
Use a <table>. Its easy, semantically correct, and you'll be done in 5 minutes.

How to access a RowDataPacket object

You can copy all enumerable own properties of an object to a new one by Object.assign(target, ...sources):

trivial_object = Object.assign({}, non_trivial_object);

so in your scenario, it should be enough to change



ret.push(Object.assign({}, i));

cut or awk command to print first field of first row


sed 'NUMq;d'  /etc/*release | awk {'print $1}'

where NUM is line number

ex. sed '1q;d'  /etc/*release | awk {'print $1}'

Using Oracle to_date function for date string with milliseconds

You have to change date class to timestamp.

String s=df.format(c.getTime());
java.util.Date parsedUtilDate = df.parse(s);  
java.sql.Timestamp timestamp = new java.sql.Timestamp(parsedUtilDate.getTime());

What does Ruby have that Python doesn't, and vice versa?

In Ruby, when you import a file with require, all the things defined in that file will end up in your global namespace.

With Cargo you can "require libraries without cluttering your namespace".

# foo-1.0.0.rb
class Foo
  VERSION = "1.0.0"

# foo-2.0.0.rb
class Foo
  VERSION = "2.0.0"
>> Foo1 = import("foo-1.0.0")
>> Foo2 = import("foo-2.0.0")
>> Foo1::VERSION
=> "1.0.0"
>> Foo2::VERSION
=> "2.0.0"

Pass arguments into C program from command line

Take a look at the getopt library; it's pretty much the gold standard for this sort of thing.

HTML5 iFrame Seamless Attribute

Use the frameborder attribute on your iframe and set it to frameborder="0" . That produces the seamless look. Now you maybe saying I want the nested iframe to control rather I have scroll bars. Then you need to whip up a JavaScript script file that calculates height minus any headers and set the height. Debounce is javascript plugin needed to make sure resize works appropriately in older browsers and sometimes chrome. That will get you in the right direction.

SQL Network Interfaces, error: 50 - Local Database Runtime error occurred. Cannot create an automatic instance

An instance might be corrupted or not updated properly.

Try these Commands:

C:\>sqllocaldb stop MSSQLLocalDB
LocalDB instance "MSSQLLocalDB" stopped.
C:\>sqllocaldb delete MSSQLLocalDB
LocalDB instance "MSSQLLocalDB" deleted.
C:\>sqllocaldb create MSSQLLocalDB
LocalDB instance "MSSQLLocalDB" created with version 13.0.1601.5.
C:\>sqllocaldb start MSSQLLocalDB
LocalDB instance "MSSQLLocalDB" started.

How can I split a shell command over multiple lines when using an IF statement?

For Windows/WSL/Cygwin etc users:

Make sure that your line endings are standard Unix line feeds, i.e. \n (LF) only.

Using Windows line endings \r\n (CRLF) line endings will break the command line break.

This is because having \ at the end of a line with Windows line ending translates to \ \r \n.
As Mark correctly explains above:

The line-continuation will fail if you have whitespace after the backslash and before the newline.

This includes not just space () or tabs (\t) but also the carriage return (\r).

What does the "assert" keyword do?

Although I have read a lot documentation about this one, I'm still confusing on how, when, and where to use it.

Make it very simple to understand:

When you have a similar situation like this:

    String strA = null;
    String strB = null;
    if (2 > 1){
        strA = "Hello World";

    strB = strA.toLowerCase(); 

You might receive warning (displaying yellow line on strB = strA.toLowerCase(); ) that strA might produce a NULL value to strB. Although you know that strB is absolutely won't be null in the end, just in case, you use assert to

1. Disable the warning.

2. Throw Exception error IF worst thing happens (when you run your application).

Sometime, when you compile your code, you don't get your result and it's a bug. But the application won't crash, and you spend a very hard time to find where is causing this bug.

So, if you put assert, like this:

    assert strA != null; //Adding here
    strB = strA .toLowerCase();

you tell the compiler that strA is absolutely not a null value, it can 'peacefully' turn off the warning. IF it is NULL (worst case happens), it will stop the application and throw a bug to you to locate it.

Getting request URL in a servlet

The getRequestURL() omits the port when it is 80 while the scheme is http, or when it is 443 while the scheme is https.

So, just use getRequestURL() if all you want is obtaining the entire URL. This does however not include the GET query string. You may want to construct it as follows then:

StringBuffer requestURL = request.getRequestURL();
if (request.getQueryString() != null) {
String completeURL = requestURL.toString();

How to install .MSI using PowerShell

#$computerList = "Server Name"
#$regVar = "Name of the package "
#$packageName = "Packe name "
$computerList = $args[0]
$regVar = $args[1]
$packageName = $args[2]
foreach ($computer in $computerList)
    Write-Host "Connecting to $computer...."
    Invoke-Command -ComputerName $computer -Authentication Kerberos -ScriptBlock {

        Write-Host "Connected to $computer"
        if ([IntPtr]::Size -eq 4)
            $registryLocation = Get-ChildItem "HKLM:\Software\Microsoft\Windows\CurrentVersion\Uninstall\"
            Write-Host "Connected to 32bit Architecture"
            $registryLocation = Get-ChildItem "HKLM:\Software\Wow6432Node\Microsoft\Windows\CurrentVersion\Uninstall\"
            Write-Host "Connected to 64bit Architecture"
        Write-Host "Finding previous version of `enter code here`$regVar...."
        foreach ($registryItem in $registryLocation)
            if((Get-itemproperty $registryItem.PSPath).DisplayName -match $regVar)
                Write-Host "Found $regVar" (Get-itemproperty $registryItem.PSPath).DisplayName
                $UninstallString = (Get-itemproperty $registryItem.PSPath).UninstallString
                    $match = [RegEx]::Match($uninstallString, "{.*?}")
                    $args = "/x $($match.Value) /qb"
                    Write-Host "Uninstalling $regVar...."
                    [diagnostics.process]::start("msiexec", $args).WaitForExit() 
                    Write-Host "Uninstalled $regVar"

        $path = "\\$computer\Msi\$packageName"
        Write-Host "Installaing $path...."
        $args = " /i $path /qb"
        [diagnostics.process]::start("msiexec", $args).WaitForExit()
        Write-Host "Installed $path"
    } -ArgumentList $computer, $regVar, $packageName
Write-Host "Deployment Complete"


Setting Access-Control-Allow-Origin in ASP.Net MVC - simplest possible method

I'm using DotNet Core MVC and after fighting for a few hours with nuget packages, Startup.cs, attributes, and this place, I simply added this to the MVC action:

Response.Headers.Add("Access-Control-Allow-Origin", "*");

I realise this is pretty clunky, but it's all I needed, and nothing else wanted to add those headers. I hope this helps someone else!

Google Android USB Driver and ADB

Looks like the Google USB drivers have been updated to support Glass out of the box, so as long as you use the latest drivers, you should be able to access Glass via ADB. In my particular situation, I had connected Glass to my machine sometime mid-2014 but did nothing with it. Now when I was trying to connect it, I would not see it show up in ADB despite showing up in Device Manager. After much trial and error, I found out that I had to:

  1. Go into Device Manager
  2. Right click "Android ADB Interface" under "SAMSUNG Android Phone"
  3. Click "Uninstall". BE SURE "Delete the driver software for this device" is checked.
  4. Disconnect and reconnect Google Glass.

I was then able to reinstall the driver via regular Windows update. This forced it to look for the newest driver. Not sure why it was not getting updated before, but I hope this will help someone out there still struggling with this.

Missing `server' JVM (Java\jre7\bin\server\jvm.dll.)

To Fix The "Missing "server" JVM at C:\Program Files\Java\jre7\bin\server\jvm­­.dll, please install or use the JRE or JDK that contains these missing components.

Follow these steps:

Go to and install Java JRE7 (Check if Java 6 is not installed already)

After that, go to C:/Program files/java/jre7/bin

Here, create an folder called Server

Now go into the C:/Program files/java/jre7/bin/client folder

Copy all the data in this folder into the new C:/Program files/java/jre7/bin/Server folder

How to convert file to base64 in JavaScript?

const fileInput = document.querySelector('input');

fileInput.addEventListener('change', (e) => {

// get a reference to the file
const file =[0];

// encode the file using the FileReader API
const reader = new FileReader();
reader.onloadend = () => {

    // use a regex to remove data url part
    const base64String = reader.result
        .replace('data:', '')
        .replace(/^.+,/, '');

    // log to console
    // logs wL2dvYWwgbW9yZ...

TCP: can two different sockets share a port?

No. It is not possible to share the same port at a particular instant. But you can make your application such a way that it will make the port access at different instant.

Programmatically find the number of cores on a machine

One more Windows recipe: use system-wide environment variable NUMBER_OF_PROCESSORS:

printf("%d\n", atoi(getenv("NUMBER_OF_PROCESSORS")));

What is the function __construct used for?

__construct simply initiates a class. Suppose you have the following code;

Class Person { 

 function __construct() {
   echo 'Hello';


$person = new Person();

//the result 'Hello' will be shown.

We did not create another function to echo the word 'Hello'. It simply shows that the keyword __construct is quite useful in initiating a class or an object.

How to round down to nearest integer in MySQL?

It can be done in the following two ways:

  • select floor(desired_field_value) from table
  • select round(desired_field_value-0.5) from table

The 2nd-way explanation: Assume 12345.7344 integer. So, 12345.7344 - 0.5 = 12345.2344 and rounding off the result will be 12345.

How to download a file using a Java REST service and a data stream

See example here: Input and Output binary streams using JERSEY?

Pseudo code would be something like this (there are a few other similar options in above mentioned post):

public StreamingOutput getFileContent() throws Exception {
     public void write(OutputStream output) throws IOException, WebApplicationException {
        try {
          // 1. Get Stream to file from first server
          while(<read stream from first server>) {
              output.write(<bytes read from first server>)
        } catch (Exception e) {
            throw new WebApplicationException(e);
        } finally {
              // close input stream

Getting the "real" Facebook profile picture URL from graph API

Hmm..i tried everything to get url to user image.The perfect solution was fql use like this->

    $fql_b = 'SELECT pic from user where uid = ' . $user_id;
    $ret_obj_b = $facebook->api(array(
                               'method' => 'fql.query',
                               'query' => $fql_b,

             $dp_url =$ret_obj_b[0]['pic'];

replace pic by big,pic_square to get other desired results. Hope IT HELPED....

How to temporarily exit Vim and go back

If you're using Neovim, you can do the following:

  • :terminal command to bring up a terminal window.
  • Do your terminal stuff
  • Type exit to kill the terminal process
  • Press any key to return to Neovim