Programs & Examples On #Mediarss

Why is my element value not getting changed? Am I using the wrong function?

There are two issues in your code.

  1. Use getElementByName instead of getElement**s**ByName
  2. use the value in lowercase instead of Value.

Python append() vs. + operator on lists, why do these give different results?

To explain "why":

The + operation adds the array elements to the original array. The array.append operation inserts the array (or any object) into the end of the original array, which results in a reference to self in that spot (hence the infinite recursion).

The difference here is that the + operation acts specific when you add an array (it's overloaded like others, see this chapter on sequences) by concatenating the element. The append-method however does literally what you ask: append the object on the right-hand side that you give it (the array or any other object), instead of taking its elements.

An alternative

Use extend() if you want to use a function that acts similar to the + operator (as others have shown here as well). It's not wise to do the opposite: to try to mimic append with the + operator for lists (see my earlier link on why).

Little history

For fun, a little history: the birth of the array module in Python in February 1993. it might surprise you, but arrays were added way after sequences and lists came into existence.

Read input from console in Ruby?

if you want to hold the arguments from Terminal, try the following code:

A = ARGV[0].to_i
B = ARGV[1].to_i

puts "#{A} + #{B} = #{A + B}"

How to set Spinner default value to null?

is it possible have a spinner that loads with nothing selected

Only if there is no data. If you have 1+ items in the SpinnerAdapter, the Spinner will always have a selection.

Spinners are not designed to be command widgets. Users will not expect a selection in a Spinner to start an activity. Please consider using something else, like a ListView or GridView, instead of a Spinner.


BTW, I forgot to mention -- you can always put an extra entry in your adapter that represents "no selection", and make it the initial selected item in the Spinner.

There is no tracking information for the current branch

1) git branch --set-upstream-to=origin/<master_branch> feature/<your_current_branch>

2) git pull

How to receive JSON as an MVC 5 action method parameter

You are sending a array of string

var usersRoles = [];
jQuery("#dualSelectRoles2 option").each(function () {

So change model type accordingly

 public ActionResult AddUser(List<string> model)

How to output to the console in C++/Windows

If you have a none-console Windows application, you can create a console with the AllocConsole function. Once created, you can write to it using the normal std::cout methods.

Find if variable is divisible by 2

Use modulus:

// Will evaluate to true if the variable is divisible by 2
variable % 2 === 0  

How to compare the contents of two string objects in PowerShell

You want to do $arrayOfString[0].Title -eq $myPbiject.item(0).Title

-match is for regex matching ( the second argument is a regex )

Why cannot cast Integer to String in java?

You can't cast explicitly anything to a String that isn't a String. You should use either:

"" + myInt;





I prefer the second form, but I think it's personal choice.

Edit OK, here's why I prefer the second form. The first form, when compiled, could instantiate a StringBuffer (in Java 1.4) or a StringBuilder in 1.5; one more thing to be garbage collected. The compiler doesn't optimise this as far as I could tell. The second form also has an analogue, Integer.toString(myInt, radix) that lets you specify whether you want hex, octal, etc. If you want to be consistent in your code (purely aesthetically, I guess) the second form can be used in more places.

Edit 2 I assumed you meant that your integer was an int and not an Integer. If it's already an Integer, just use toString() on it and be done.

Giving a border to an HTML table row, <tr>

adding border-spacing: 0rem 0.5rem; creates a space for each cell (td, th) items on its bottom while leaving no space between the cells{
        border-collapse: separate;
        border-spacing: 0rem 0.5rem;
    } thead tr.border-row the, tbody tr.border-row td, tbody tr.border-row th{
        border-top: 1px solid #EAEAEA;
        border-bottom: 1px solid #EAEAEA;
        vertical-align: middle;
        white-space: nowrap;
        font-size: 0.875rem;
    } thead tr.border-row th:first-child, tbody tr.border-row td:first-child{
        border-left: 1px solid #EAEAEA;
    } thead tr.border-row th:last-child, tbody tr.border-row td:last-child{
        border-right: 1px solid #EAEAEA;

SQL order string as number

This works for me.

select * from tablename
order by cast(columnname as int) asc

Possible to extend types in Typescript?

May be below approach will be helpful for someone TS with reactjs

interface Event {
   name: string;
   dateCreated: string;
   type: string;

interface UserEvent<T> extends Event<T> {
    UserId: string;

npm install error from the terminal

First download json package file from and then run npm install from terminal.

Module not found: Error: Can't resolve 'core-js/es6'

I found possible answer. You have core-js version 3.0, and this version doesn't have separate folders for ES6 and ES7; that's why the application cannot find correct paths.

To resolve this error, you can downgrade the core-js version to 2.5.7. This version produces correct catalogs structure, with separate ES6 and ES7 folders.

To downgrade the version, simply run:

npm i -S [email protected]

In my case, with Angular, this works ok.

Fix CSS hover on iPhone/iPad/iPod

  1. Assigning an event listener to the target element seems to work. (Works with 'click', at least.) CSS hover on ios works only if an event listener is assigned

  2. Wrapping the target element in an a[href=trivial] also seems to work.

A related note/diagram on mobile Safari's algorithm for handling clicks and other events is here: Is it possible to force ignore the :hover pseudoclass for iPhone/iPad users?

Run cron job only if it isn't already running

Use flock. It's new. It's better.

Now you don't have to write the code yourself. Check out more reasons here:

/usr/bin/flock -n /tmp/my.lockfile /usr/local/bin/my_script

How to save a plot into a PDF file without a large margin around

It seems to me that all approaches (file exchange solutions unconsidered) here are lacking the essential step, or finally leading to it via some blurry workarounds.

The figure size needs to equal the paper size and the white margins are gone.

A = hgload('myFigure.fig');

% set desired output size
set(A, 'Units','centimeters')
height = 15;
width = 19;

% the last two parameters of 'Position' define the figure size
set(A, 'Position',[25 5 width height],...
       'PaperSize',[width height],...
       'InvertHardcopy', 'off',...
       'Renderer','painters'...     %recommended if there are no alphamaps


Will give you a pdf output as your figure appears, in exactly the size you want. If you want to get it even tighter you can combine this solution with the answer of b3.

Storing database records into array


// run query
$query = mysql_query("SELECT * FROM table");

// set array
$array = array();

// look through query
while($row = mysql_fetch_assoc($query)){

  // add each row returned into an array
  $array[] = $row;

  // OR just echo the data:
  echo $row['username']; // etc


// debug:
print_r($array); // show all array data
echo $array[0]['username']; // print the first rows username

MySQL - Rows to Columns

use subquery

SELECT  hostid, 
    (SELECT VALUE FROM TableTest WHERE ITEMNAME='A' AND hostid = t1.hostid) AS A,
    (SELECT VALUE FROM TableTest WHERE ITEMNAME='B' AND hostid = t1.hostid) AS B,
    (SELECT VALUE FROM TableTest WHERE ITEMNAME='C' AND hostid = t1.hostid) AS C
FROM TableTest AS T1
GROUP BY hostid

but it will be a problem if sub query resulting more than a row, use further aggregate function in the subquery

How do you kill all current connections to a SQL Server 2005 database?

Kill it, and kill it with fire:

USE master

DECLARE @dbname sysname
SET @dbname = 'yourdbname'

DECLARE @spid int
SELECT @spid = min(spid) from master.dbo.sysprocesses where dbid = db_id(@dbname)
EXECUTE ('KILL ' + @spid)
SELECT @spid = min(spid) from master.dbo.sysprocesses where dbid = db_id(@dbname) AND spid > @spid

Better way to remove specific characters from a Perl string

You've misunderstood how character classes are used:

$varTemp =~ s/[\$#@~!&*()\[\];.,:?^ `\\\/]+//g;

does the same as your regex (assuming you didn't mean to remove ' characters from your strings).

Edit: The + allows several of those "special characters" to match at once, so it should also be faster.

Bootstrap 3 jquery event for active tab change

I use another approach.

Just try to find all a where id starts from some substring.


$('a[id^=v-photos-tab]').click(function () {
     alert("Handler for .click() called.");


<a class="nav-item nav-link active show"  id="v-photos-tab-3a623245-7dc7-4a22-90d0-62705ad0c62b" data-toggle="pill" href="#v-photos-3a623245-7dc7-4a22-90d0-62705ad0c62b" role="tab" aria-controls="v-requestbase-photos" aria-selected="true"><span>Cool photos</span></a>

password-check directive in angularjs

Is this not good enough:

<input type="password" ng-model="passwd1" />
<input type="password" ng-model="passwd2" />
<label ng-show="passwd1 != passwd2">Passwords do not match...</label>
<button ng-disabled="passwd1 != passwd2">Save</button>

Simple, and works just fine for me.

Java: how do I initialize an array size if it's unknown?

String line=sc.nextLine();
    int counter=1;
    for(int i=0;i<line.length();i++) {
        if(line.charAt(i)==' ') {
    long[] numbers=new long[counter];
    for(int i=0;i<line.length();i++){
        int j=i;
        while(true) {
            if(j>=line.length() || line.charAt(j)==' ') {
    for(int i=0;i<counter;i++) {

I always use this code for situations like this. beside you can recognize two or three or more digit numbers.

How do I call REST API from an android app?

  1. If you want to integrate Retrofit (all steps defined here):

Goto my blog : retrofit with kotlin

  1. Please use android-async-http library.

the link below explains everything step by step.

Here are sample apps:



Create a class :

public class HttpUtils {
  private static final String BASE_URL = "";
  private static AsyncHttpClient client = new AsyncHttpClient();

  public static void get(String url, RequestParams params, AsyncHttpResponseHandler responseHandler) {
      client.get(getAbsoluteUrl(url), params, responseHandler);

  public static void post(String url, RequestParams params, AsyncHttpResponseHandler responseHandler) {, params, responseHandler);
  public static void getByUrl(String url, RequestParams params, AsyncHttpResponseHandler responseHandler) {
      client.get(url, params, responseHandler);

  public static void postByUrl(String url, RequestParams params, AsyncHttpResponseHandler responseHandler) {, params, responseHandler);

  private static String getAbsoluteUrl(String relativeUrl) {
      return BASE_URL + relativeUrl;

Call Method :

    RequestParams rp = new RequestParams();
    rp.add("username", "aaa"); rp.add("password", "aaa@123");
               , rp, new JsonHttpResponseHandler() {
        public void onSuccess(int statusCode, Header[] headers, JSONObject response) {
            // If the response is JSONObject instead of expected JSONArray
            Log.d("asd", "---------------- this is response : " + response);
            try {
                JSONObject serverResp = new JSONObject(response.toString());                                                
            } catch (JSONException e) {
                // TODO Auto-generated catch block
        public void onSuccess(int statusCode, Header[] headers, JSONArray timeline) {
            // Pull out the first event on the public timeline

Please grant internet permission in your manifest file.

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

you can add compile '' for Header[] and compile 'org.json:json:20160212' for JSONObject in build.gradle file if required.

Passing multiple argument through CommandArgument of Button in

You can pass semicolon separated values as command argument and then split the string and use it.

<asp:TemplateField ShowHeader="false">
       <asp:LinkButton ID="lnkCustomize" Text="Customize"  CommandName="Customize"  CommandArgument='<%#Eval("IdTemplate") + ";" +Eval("EntityId")%>'  runat="server"> 

at server side

protected void gridview_RowCommand(object sender, GridViewCommandEventArgs e)
      string[] arg = new string[2];
      arg = e.CommandArgument.ToString().Split(';');
      Session["IdTemplate"] = arg[0];
      Session["IdEntity"] = arg[1];

Hope it helps!!!!

Grant Select on a view not base table when base table is in a different database

I also had this problem. I used information from link, mentioned above, and found quick solution. If you have different schema, lets say test, and create user utest, owner of schema test and among views in schema test you have view vTestView, based on tables from schema dbo, while selecting from it you'll get error mentioned above - no access to base objects. It was enough for me to execute statement


which means that I change an ownership of vTextView from schema it belongs to (test) to database user dbo, owner of schema dbo. After that without any other permissions required user utest will be able to access data from test.vTestView

String comparison technique used by Python

A pure Python equivalent for string comparisons would be:

def less(string1, string2):
    # Compare character by character
    for idx in range(min(len(string1), len(string2))):
        # Get the "value" of the character
        ordinal1, ordinal2 = ord(string1[idx]), ord(string2[idx])
        # If the "value" is identical check the next characters
        if ordinal1 == ordinal2:
        # It's not equal so we're finished at this index and can evaluate which is smaller.
            return ordinal1 < ordinal2
    # We're out of characters and all were equal, so the result depends on the length
    # of the strings.
    return len(string1) < len(string2)

This function does the equivalent of the real method (Python 3.6 and Python 2.7) just a lot slower. Also note that the implementation isn't exactly "pythonic" and only works for < comparisons. It's just to illustrate how it works. I haven't checked if it works like Pythons comparison for combined unicode characters.

A more general variant would be:

from operator import lt, gt

def compare(string1, string2, less=True):
    op = lt if less else gt
    for char1, char2 in zip(string1, string2):
        ordinal1, ordinal2 = ord(char1), ord(char1)
        if ordinal1 == ordinal2:
            return op(ordinal1, ordinal2)
    return op(len(string1), len(string2))

How to configure "Shorten command line" method for whole project in IntelliJ

You can set up a default way to shorten the command line and use it as a template for further configurations by changing the default JUnit Run/Debug Configuration template. Then all new Run/Debug configuration you create in project will use the same option.

Here is the related blog post about configurable command line shortener option.

Reload parent window from child window


worked for me.

Conda version pip install -r requirements.txt --target ./lib

would this work?

cat requirements.txt | while read x; do conda install "$x" -p ./lib ;done


conda install --file requirements.txt -p ./lib

Installing PIL with pip

For CentOS:

yum install python-imaging

Groovy executing shell commands

To add one more important information to above provided answers -

For a process

def proc = command.execute();

always try to use

def outputStream = new StringBuffer();
proc.waitForProcessOutput(outputStream, System.err)
//proc.waitForProcessOutput(System.out, System.err)

rather than

def output =;

to capture the outputs after executing commands in groovy as the latter is a blocking call (SO question for reason).

How to check if a stored procedure exists before creating it

CREATE Procedure IF NOT EXISTS 'Your proc-name' () BEGIN ... END

How can I change the language (to english) in Oracle SQL Developer?

Try to set user.language and properties in sqldeveloper.conf file located in sqldeveloper\bin folder (%APPDATA%\sqldeveloper\<version>\product.conf for more recent versions) .
Sample for set french language:

IncludeConfFile ../../ide/bin/ide.conf

SetJavaHome D:\jdk1.6.0_25

AddVMOption  -Doracle.ide.util.AddinPolicyUtils.OVERRIDE_FLAG=true

AddVMOption -Dsun.java2d.ddoffscreen=false

AddVMOption -Duser.language=fr
AddVMOption  -XX:MaxPermSize=128M

AddVMOption -Doracle.jdbc.mapDateToTimestamp=false  
IncludeConfFile  sqldeveloper-nondebug.conf

To switch off language try to remove its support by editing oracle.translated.locales option in ide.boot file (located in ide\bin folder).
For example, if I want to 'break' french language support this option will be:

oracle.translated.locales = de,es,it,ja,ko,pt_BR,zh_CN,zh_TW

The original value was:

oracle.translated.locales = de,fr,es,it,ja,ko,pt_BR,zh_CN,zh_TW

The configuration above (sqldeveloper.conf file) will be wrong after remove french support and the french language does not appear as GUI localization.

Best TCP port number range for internal applications

I decided to download the assigned port numbers from IANA, filter out the used ports, and sort each "Unassigned" range in order of most ports available, descending. This did not work, since the csv file has ranges marked as "Unassigned" that overlap other port number reservations. I manually expanded the ranges of assigned port numbers, leaving me with a list of all assigned port numbers. I then sorted that list and generated my own list of unassigned ranges.

Since this page ranked very high in my search about the topic, I figured I'd post the largest ranges here for anyone else who is interested. These are for both TCP and UDP where the number of ports in the range is at least 500.

Total   Start   End
829     29170   29998
815     38866   39680
710     41798   42507
681     43442   44122
661     46337   46997
643     35358   36000
609     36866   37474
596     38204   38799
592     33657   34248
571     30261   30831
563     41231   41793
542     21011   21552
528     28590   29117
521     14415   14935
510     26490   26999

Source (via the CSV download button):

How to have multiple colors in a Windows batch file?

Combining dbenham's bird and syntax with skrebbel's powershell write-host method, it seems that powershell can render complex art more quickly than dbenham's pure batch method (well, after powershell has been primed once, anyway). Minimal massaging of the strings are needed, although I haven't tested this with anything other than the bird. If you want a bright green end-of-transmission character for example, you may be out of luck. :)

This method requires echoing out to a temp file, simply because invoking powershell for each call :c takes forever, and it's much faster to queue the output for one powershell invocation. But it does have the advantage of simplicity and efficiency.

@echo off
setlocal disableDelayedExpansion
set q=^"
call :c 0E "                ,      .-;" /n
call :c 0E "             ,  |\    / /  __," /n
call :c 0E "             |\ '.`-.|  |.'.-'" /n
call :c 0E "              \`'-:  `; : /" /n
call :c 0E "               `-._'.  \'|" /n
call :c 0E "              ,_.-=` ` `  ~,_" /n
call :c 0E "               '--,.    "&call :c 0c ".-. "&call :c 0E ",=!q!." /n
call :c 0E "                 /     "&call :c 0c "{ "&call :c 0A "* "&call :c 0c ")"&call :c 0E "`"&call :c 06 ";-."&call :c 0E "}" /n
call :c 0E "                 |      "&call :c 0c "'-' "&call :c 06 "/__ |" /n
call :c 0E "                 /          "&call :c 06 "\_,\|" /n
call :c 0E "                 |          (" /n
call :c 0E "             "&call :c 0c "__ "&call :c 0E "/ '          \" /n
call :c 02 "     /\_    "&call :c 0c "/,'`"&call :c 0E "|     '   "&call :c 0c ".-~!q!~~-." /n
call :c 02 "     |`.\_ "&call :c 0c "|   "&call :c 0E "/  ' ,    "&call :c 0c "/        \" /n
call :c 02 "   _/  `, \"&call :c 0c "|  "&call :c 0E "; ,     . "&call :c 0c "|  ,  '  . |" /n
call :c 02 "   \   `,  "&call :c 0c "|  "&call :c 0E "|  ,  ,   "&call :c 0c "|  :  ;  : |" /n
call :c 02 "   _\  `,  "&call :c 0c "\  "&call :c 0E "|.     ,  "&call :c 0c "|  |  |  | |" /n
call :c 02 "   \`  `.   "&call :c 0c "\ "&call :c 0E "|   '     "&call :c 0A "|"&call :c 0c "\_|-'|_,'\|" /n
call :c 02 "   _\   `,   "&call :c 0A "`"&call :c 0E "\  '  . ' "&call :c 0A "| |  | |  |           "&call :c 02 "__" /n
call :c 02 "   \     `,   "&call :c 0E "| ,  '    "&call :c 0A "|_/'-|_\_/     "&call :c 02 "__ ,-;` /" /n
call :c 02 "    \    `,    "&call :c 0E "\ .  , ' .| | | | |   "&call :c 02 "_/' ` _=`|" /n
call :c 02 "     `\    `,   "&call :c 0E "\     ,  | | | | |"&call :c 02 "_/'   .=!q!  /" /n
call :c 02 "     \`     `,   "&call :c 0E "`\      \/|,| ;"&call :c 02 "/'   .=!q!    |" /n
call :c 02 "      \      `,    "&call :c 0E "`\' ,  | ; "&call :c 02 "/'    =!q!    _/" /n
call :c 02 "       `\     `,  "&call :c 05 ".-!q!!q!-. "&call :c 0E "': "&call :c 02 "/'    =!q!     /" /n
call :c 02 "    jgs _`\    ;"&call :c 05 "_{  '   ; "&call :c 02 "/'    =!q!      /" /n
call :c 02 "       _\`-/__"&call :c 05 ".~  `."&call :c 07 "8"&call :c 05 ".'.!q!`~-. "&call :c 02 "=!q!     _,/" /n
call :c 02 "    __\      "&call :c 05 "{   '-."&call :c 07 "|"&call :c 05 ".'.--~'`}"&call :c 02 "    _/" /n
call :c 02 "    \    .=!q!` "&call :c 05 "}.-~!q!'"&call :c 0D "u"&call :c 05 "'-. '-..'  "&call :c 02 "__/" /n
call :c 02 "   _/  .!q!    "&call :c 05 "{  -'.~('-._,.'"&call :c 02 "\_,/" /n
call :c 02 "  /  .!q!    _/'"&call :c 05 "`--; ;  `.  ;" /n
call :c 02 "   .=!q!  _/'      "&call :c 05 "`-..__,-'" /n
call :c 02 "    __/'" /n

if exist "%temp%\color.psm1" (
    powershell -command "&{set-executionpolicy remotesigned; Import-Module '%temp%\color.psm1'}"
    del "%temp%\color.psm1"


exit /b


:c <color pair> <string> </n>
setlocal enabledelayedexpansion
set "colors=0-black;1-darkblue;2-darkgreen;3-darkcyan;4-darkred;5-darkmagenta;6-darkyellow;7-gray;8-darkgray;9-blue;a-green;b-cyan;c-red;d-magenta;e-yellow;f-white"
set "p=%~1"
set "bg=!colors:*%p:~0,1%-=!"
set bg=%bg:;=&rem.%
set "fg=!colors:*%p:~-1%-=!"
set fg=%fg:;=&rem.%

if not "%~3"=="/n" set "br=-nonewline"
set "str=%~2" & set "str=!str:'=''!"

>>"%temp%\color.psm1" echo write-host '!str!' -foregroundcolor '%fg%' -backgroundcolor '%bg%' %br%


enter image description here

How to establish a connection pool in JDBC?

Vibur DBCP is another library for that purpose. Several examples showing how to configure it for use with Hibernate, Spring+Hibernate, or programatically, can be found on its website:

Also, see the disclaimer here.

init-param and context-param

<init-param> will be used if you want to initialize some parameter for a particular servlet. When request come to servlet first its init method will be called then doGet/doPost whereas if you want to initialize some variable for whole application you will need to use <context-param> . Every servlet will have access to the context variable.

Send mail via CMD console

Unless you want to talk to an SMTP server directly via telnet you'd use commandline mailers like blat:

blat -to [email protected] -f [email protected] -s "mail subject" ^
  -server -body "message text"

or bmail:

bmail -s -t [email protected] -f [email protected] -h ^
  -a "mail subject" -b "message text"

You could also write your own mailer in VBScript or PowerShell.

Dynamically add event listener

Renderer has been deprecated in Angular 4.0.0-rc.1, read the update below

The angular2 way is to use listen or listenGlobal from Renderer

For example, if you want to add a click event to a Component, you have to use Renderer and ElementRef (this gives you as well the option to use ViewChild, or anything that retrieves the nativeElement)

constructor(elementRef: ElementRef, renderer: Renderer) {

    // Listen to click events in the component
    renderer.listen(elementRef.nativeElement, 'click', (event) => {
      // Do something with 'event'

You can use listenGlobal that will give you access to document, body, etc.

renderer.listenGlobal('document', 'click', (event) => {
  // Do something with 'event'

Note that since beta.2 both listen and listenGlobal return a function to remove the listener (see breaking changes section from changelog for beta.2). This is to avoid memory leaks in big applications (see #6686).

So to remove the listener we added dynamically we must assign listen or listenGlobal to a variable that will hold the function returned, and then we execute it.

// listenFunc will hold the function returned by "renderer.listen"
listenFunc: Function;

// globalListenFunc will hold the function returned by "renderer.listenGlobal"
globalListenFunc: Function;

constructor(elementRef: ElementRef, renderer: Renderer) {
    // We cache the function "listen" returns
    this.listenFunc = renderer.listen(elementRef.nativeElement, 'click', (event) => {
        // Do something with 'event'

    // We cache the function "listenGlobal" returns
    this.globalListenFunc = renderer.listenGlobal('document', 'click', (event) => {
        // Do something with 'event'

ngOnDestroy() {
    // We execute both functions to remove the respectives listeners

    // Removes "listen" listener
    // Removs "listenGlobal" listener

Here's a plnkr with an example working. The example contains the usage of listen and listenGlobal.

Using RendererV2 with Angular 4.0.0-rc.1+ (Renderer2 since 4.0.0-rc.3)

  • 25/02/2017: Renderer has been deprecated, now we should use RendererV2 (see line below). See the commit.

  • 10/03/2017: RendererV2 was renamed to Renderer2. See the breaking changes.

RendererV2 has no more listenGlobal function for global events (document, body, window). It only has a listen function which achieves both functionalities.

For reference, I'm copy & pasting the source code of the DOM Renderer implementation since it may change (yes, it's angular!).

listen(target: 'window'|'document'|'body'|any, event: string, callback: (event: any) => boolean):
      () => void {
    if (typeof target === 'string') {
      return <() => void>this.eventManager.addGlobalEventListener(
          target, event, decoratePreventDefault(callback));
    return <() => void>this.eventManager.addEventListener(
               target, event, decoratePreventDefault(callback)) as() => void;

As you can see, now it verifies if we're passing a string (document, body or window), in which case it will use an internal addGlobalEventListener function. In any other case, when we pass an element (nativeElement) it will use a simple addEventListener

To remove the listener it's the same as it was with Renderer in angular 2.x. listen returns a function, then call that function.


// Add listeners
let global = this.renderer.listen('document', 'click', (evt) => {
  console.log('Clicking the document', evt);

let simple = this.renderer.listen(this.myButton.nativeElement, 'click', (evt) => {
  console.log('Clicking the button', evt);

// Remove listeners

plnkr with Angular 4.0.0-rc.1 using RendererV2

plnkr with Angular 4.0.0-rc.3 using Renderer2

Connecting to SQL Server with Visual Studio Express Editions

I just happened to have started my home business application in windows forms for the convenience. I'm currently using Visual C# Express 2010 / SQL Server 2008 R2 Express to develop it. I got the same problem as OP where I need to connect to an instance of SQL server. I'm skipping details here but that database will be a merged database synched between 2-3 computers that will also use the application I'm developing right now.

I found a quick workaround, at least, I think I did because I'm now able to use my stored procedures in tableadapters without any issues so far.

I copy pasted an SQL connection that I used in a different project at work (VS2010 Premium) in the app.config and changed everything I needed there. When I went back to my Settings.settings, I just had to confirm that I wanted what was inside the app.config file. The only downsides I can see is that you can't "test" the connection since when you go inside the configuration of the connection string you can't go anywhere since "SQL Server" is not an option. The other downside is that you need to input everything manually since you can't use any wizards to make it work.

I don't know if I should have done it that way but at least I can connect to my SQL server now :).


It only works with SQL Server 2008 R2 Express instances. If you try with SQL Server 2008 R2 Workgroup and up, you'll get a nasty warning from Visual C# 2010 Express telling you that "you can't use that connection with the current version of Visual Studio". I got that when I was trying to modify some of my tableadapters. I switched back to an SQL Express instance to develop and it's working fine again.

Position a div container on the right side

Is this what you wanted? -

Floats on both sides now




<div id="wrapper">
    <div id="c1">con1</div>
    <div id="c2">con2</div>

How to add a line break in an Android TextView?

try this:

         TextView calloutContent = new TextView(getApplicationContext());
         calloutContent.setText(" line 1" + System.getProperty ("line.separator")+"  line2" );

Load and execute external js file in node.js with access to local variables?

If you are writing code for Node, using Node modules as described by Ivan is without a doubt the way to go.

However, if you need to load JavaScript that has already been written and isn't aware of node, the vm module is the way to go (and definitely preferable to eval).

For example, here is my execfile module, which evaluates the script at path in either context or the global context:

var vm = require("vm");
var fs = require("fs");
module.exports = function(path, context) {
  var data = fs.readFileSync(path);
  vm.runInNewContext(data, context, path);

Also note: modules loaded with require(…) don't have access to the global context.

Simple search MySQL database using php



$errors = FALSE;
$errorMessage = "";

  $errors = TRUE;
  $errorMessage .= "There was a connection error <br/>";
} else if($errors != "TRUE"){
  $errors .= FALSE;

  $search = mysqli_real_escape_string($_POST['search']);

//This is functions.php
function search($searchQuery){
  echo "<div class="col-md-10 col-md-offset-1">";
  $query = query("SELECT * FROM `index` WHERE `keywords` LIKE '".$searchTerm."' ");
  while($row = mysqli_fetch_array($query)){
    $results = <<< DELIMITER
      <div class="result col-md-12">
        <a href="index.php?search={$row['id']}"> {$row['Title']} </a>
        <p class="searchDesc">{$row['description']}</p>
    echo $results;
  echo "</div>";

function errorDisplay($msg){
    $_SESSION['errors'] = $msg;
  } else if() {
    $_SESSION['errors'] .= $msg . "<br>";
function showError($msg) {
  return $msg;

Perhaps That Helps?

What is the difference between VFAT and FAT32 file systems?

Copied from

What's FAT?

FAT may sound like a strange name for a file system, but it's actually an acronym for File Allocation Table. Introduced in 1981, FAT is ancient in computer terms. Because of its age, most operating systems, including Microsoft Windows NT®, Windows 98, the Macintosh OS, and some versions of UNIX, offer support for FAT.

The FAT file system limits filenames to the 8.3 naming convention, meaning that a filename can have no more than eight characters before the period and no more than three after. Filenames in a FAT file system must also begin with a letter or number, and they can't contain spaces. Filenames aren't case sensitive.

What About VFAT?

Perhaps you've also heard of a file system called VFAT. VFAT is an extension of the FAT file system and was introduced with Windows 95. VFAT maintains backward compatibility with FAT but relaxes the rules. For example, VFAT filenames can contain up to 255 characters, spaces, and multiple periods. Although VFAT preserves the case of filenames, it's not considered case sensitive.

When you create a long filename (longer than 8.3) with VFAT, the file system actually creates two different filenames. One is the actual long filename. This name is visible to Windows 95, Windows 98, and Windows NT (4.0 and later). The second filename is called an MS-DOS® alias. An MS-DOS alias is an abbreviated form of the long filename. The file system creates the MS-DOS alias by taking the first six characters of the long filename (not counting spaces), followed by the tilde [~] and a numeric trailer. For example, the filename Brien's Document.txt would have an alias of BRIEN'~1.txt.

An interesting side effect results from the way VFAT stores its long filenames. When you create a long filename with VFAT, it uses one directory entry for the MS-DOS alias and another entry for every 13 characters of the long filename. In theory, a single long filename could occupy up to 21 directory entries. The root directory has a limit of 512 files, but if you were to use the maximum length long filenames in the root directory, you could cut this limit to a mere 24 files. Therefore, you should use long filenames very sparingly in the root directory. Other directories aren't affected by this limit.

You may be wondering why we're discussing VFAT. The reason is it's becoming more common than FAT, but aside from the differences I mentioned above, VFAT has the same limitations. When you tell Windows NT to format a partition as FAT, it actually formats the partition as VFAT. The only time you'll have a true FAT partition under Windows NT 4.0 is when you use another operating system, such as MS-DOS, to format the partition.


FAT32 is actually an extension of FAT and VFAT, first introduced with Windows 95 OEM Service Release 2 (OSR2). FAT32 greatly enhances the VFAT file system but it does have its drawbacks.

The greatest advantage to FAT32 is that it dramatically increases the amount of free hard disk space. To illustrate this point, consider that a FAT partition (also known as a FAT16 partition) allows only a certain number of clusters per partition. Therefore, as your partition size increases, the cluster size must also increase. For example, a 512-MB FAT partition has a cluster size of 8K, while a 2-GB partition has a cluster size of 32K.

This may not sound like a big deal until you consider that the FAT file system only works in single cluster increments. For example, on a 2-GB partition, a 1-byte file will occupy the entire cluster, thereby consuming 32K, or roughly 32,000 times the amount of space that the file should consume. This rule applies to every file on your hard disk, so you can see how much space can be wasted.

Converting a partition to FAT32 reduces the cluster size (and overcomes the 2-GB partition size limit). For partitions 8 GB and smaller, the cluster size is reduced to a mere 4K. As you can imagine, it's not uncommon to gain back hundreds of megabytes by converting a partition to FAT32, especially if the partition contains a lot of small files.

Note: This section of the quote/ article (1999) is out of date. Updated info quote below.

As I mentioned, FAT32 does have limitations. Unfortunately, it isn't compatible with any operating system other than Windows 98 and the OSR2 version of Windows 95. However, Windows 2000 will be able to read FAT32 partitions.

The other disadvantage is that your disk utilities and antivirus software must be FAT32-aware. Otherwise, they could interpret the new file structure as an error and try to correct it, thus destroying data in the process.

Finally, I should mention that converting to FAT32 is a one-way process. Once you've converted to FAT32, you can't convert the partition back to FAT16. Therefore, before converting to FAT32, you need to consider whether the computer will ever be used in a dual-boot environment. I should also point out that although other operating systems such as Windows NT can't directly read a FAT32 partition, they can read it across the network. Therefore, it's no problem to share information stored on a FAT32 partition with other computers on a network that run older operating systems.

Updated mentioned in comment by Doktor-J (assimilated to update out of date answer in case comment is ever lost):

I'd just like to point out that most modern operating systems (WinXP/Vista/7/8, MacOS X, most if not all Linux variants) can read FAT32, contrary to what the second-to-last paragraph suggests.

The original article was written in 1999, and being posted on a Microsoft website, probably wasn't concerned with non-Microsoft operating systems anyways.

The operating systems "excluded" by that paragraph are probably the original Windows 95, Windows NT 4.0, Windows 3.1, DOS, etc.

Sort divs in jQuery based on attribute 'data-sort'?

I used this to sort a gallery of images where the sort array would be altered by an ajax call. Hopefully it can be useful to someone.

var myArray = ['2', '3', '1'];_x000D_
var elArray = [];_x000D_
$('.imgs').each(function() {_x000D_
    elArray[$(this).data('image-id')] = $(this);_x000D_
   $('#container').append(elArray[value]); _x000D_
<script src=""></script>_x000D_
<div id='container'>_x000D_
   <div class="imgs" data-image-id='1'>1</div>_x000D_
   <div class="imgs" data-image-id='2'>2</div>_x000D_
   <div class="imgs" data-image-id='3'>3</div>_x000D_


Populating a dictionary using for loops (python)

>>> dict(zip(keys, values))
{0: 'Hi', 1: 'I', 2: 'am', 3: 'John'}

Is there any way to prevent input type="number" getting negative values?

If Number is Negative or Positive Using ES6’s Math.Sign_x000D_
const num = -8;_x000D_
// Old Way_x000D_
num === 0 ? num : (num > 0 ? 1 : -1); // -1_x000D_
// ES6 Way_x000D_
Math.sign(num); // -1

Resize a large bitmap file to scaled output file on Android

This may be useful for someone else looking at this question. I rewrote Justin's code to allow the method to receive the target size object required as well. This works very well when using Canvas. All credit should go to JUSTIN for his great initial code.

    private Bitmap getBitmap(int path, Canvas canvas) {

        Resources resource = null;
        try {
            final int IMAGE_MAX_SIZE = 1200000; // 1.2MP
            resource = getResources();

            // Decode image size
            BitmapFactory.Options options = new BitmapFactory.Options();
            options.inJustDecodeBounds = true;
            BitmapFactory.decodeResource(resource, path, options);

            int scale = 1;
            while ((options.outWidth * options.outHeight) * (1 / Math.pow(scale, 2)) > 
                  IMAGE_MAX_SIZE) {
            Log.d("TAG", "scale = " + scale + ", orig-width: " + options.outWidth + ", orig-height: " + options.outHeight);

            Bitmap pic = null;
            if (scale > 1) {
                // scale to max possible inSampleSize that still yields an image
                // larger than target
                options = new BitmapFactory.Options();
                options.inSampleSize = scale;
                pic = BitmapFactory.decodeResource(resource, path, options);

                // resize to desired dimensions
                int height = canvas.getHeight();
                int width = canvas.getWidth();
                Log.d("TAG", "1th scale operation dimenions - width: " + width + ", height: " + height);

                double y = Math.sqrt(IMAGE_MAX_SIZE
                        / (((double) width) / height));
                double x = (y / height) * width;

                Bitmap scaledBitmap = Bitmap.createScaledBitmap(pic, (int) x, (int) y, true);
                pic = scaledBitmap;

            } else {
                pic = BitmapFactory.decodeResource(resource, path);

            Log.d("TAG", "bitmap size - width: " +pic.getWidth() + ", height: " + pic.getHeight());
            return pic;
        } catch (Exception e) {
            Log.e("TAG", e.getMessage(),e);
            return null;

Justin's code is VERY effective at reducing the overhead of working with large Bitmaps.

PHP session handling errors

This was a known bug in version(s) of PHP . Depending on your server environment, you can try setting the sessions folder to 777:

/var/lib/php/session (your location may vary)

I ended up using this workaround:

ini_set('session.gc_probability', 1);

You will have to create this folder and make it writeable. I havent messed around with the permissions much, but 777 worked for me (obviously).

Make sure the place where you are storing your sessions isn't accessible to the world.

This solution may not work for everyone, but I hope it helps some people!

How to stop BackgroundWorker correctly

I agree with guys. But sometimes you have to add more things.


1) Add this worker.WorkerSupportsCancellation = true;

2) Add to you class some method to do the following things

public void KillMe()
   worker = null;

So before close your application your have to call this method.

3) Probably you can Dispose, null all variables and timers which are inside of the BackgroundWorker.

Sending E-mail using C#

Take a look at the FluentEmail library. I've blogged about it here

You have a nice and fluent api for your needs:

 .To("[email protected]")
 .Subject("New order has arrived!")
 .Body("The order details are…")  

Configure active profile in SpringBoot via Maven

You can run using the following command. Here I want to run using spring profile local:

spring-boot:run -Drun.jvmArguments=""

How to disable input conditionally in vue.js

Bear in mind that ES6 Sets/Maps don't appear to be reactive as far as i can tell, at time of writing.

How can I invert color using CSS?

Add the same color of the background to the paragraph and then invert with CSS:

div {_x000D_
    background-color: #f00;_x000D_
p { _x000D_
    color: #f00;_x000D_
    -webkit-filter: invert(100%);_x000D_
    filter: invert(100%);_x000D_
    <p>inverted color</p>_x000D_

javascript regex - look behind alternative?

This is an equivalent solution to Tim Pietzcker's answer (see also comments of same answer):


It means, match *.js except *filename.js.

To get to this solution, you can check which patterns the negative lookbehind excludes, and then exclude exactly these patterns with a negative lookahead.

Add custom icons to font awesome

Depends on what you have. If your svg icon is just a path, then it's easy enough to add that glyph by just copying the 'd' attribute to a new <glyph> element. However, the path needs to be scaled to the font's coordinate system (the EM-square, which typically is [0,0,2048,2048] - the standard for Truetype fonts) and aligned with the baseline you want.

Not all browsers support svg fonts however, so you're going to have to convert it to other formats too if you want it to work everywhere.

Fontforge can import svg files (select a glyph slot, File > Import and then select your svg image), and you can then convert to all the relevant font formats (svg, truetype, woff etc).

Linq select object from list depending on objects attribute

First, Single throws an exception if there is more than one element satisfying the criteria. Second, your criteria should only check if the Correct property is true. Right now, you are checking if a is equal to a.Correct (which will not even compile).

You should use First (which will throw if there are no such elements), or FirstOrDefault (which will return null for a reference type if there isn't such element):

// this will return the first correct answer,
// or throw an exception if there are no correct answers
var correct = answers.First(a => a.Correct); 

// this will return the first correct answer, 
// or null if there are no correct answers
var correct = answers.FirstOrDefault(a => a.Correct); 

// this will return a list containing all answers which are correct,
// or an empty list if there are no correct answers
var allCorrect = answers.Where(a => a.Correct).ToList();

Convenient way to parse incoming multipart/form-data parameters in a Servlet

Not always there's a servlet before of an upload (I could use a filter for example). Or could be that the same controller ( again a filter or also a servelt ) can serve many actions, so I think that rely on that servlet configuration to use the getPart method (only for Servlet API >= 3.0), I don't know, I don't like.

In general, I prefer independent solutions, able to live alone, and in this case is one of that.

List<FileItem> multiparts = new ServletFileUpload(new DiskFileItemFactory()).parseRequest(request);
    for (FileItem item : multiparts) {
        if (!item.isFormField()) {
            //your operations on file
        } else {
            String name = item.getFieldName();
            String value = item.getString();
            //you operations on paramters

Difference between 'cls' and 'self' in Python classes?

cls implies that method belongs to the class while self implies that the method is related to instance of the class,therefore member with cls is accessed by class name where as the one with self is accessed by instance of the is the same concept as static member and non-static members in java if you are from java background.

Java Package Does Not Exist Error

You should add the following lines in your gradle build file (build.gradle)

dependencies { 
     compile files('/usr/share/stuff')

pythonic way to do something N times without an index variable?

A slightly faster approach than looping on xrange(N) is:

import itertools

for _ in itertools.repeat(None, N):

How to animate RecyclerView items when they appear

I animated fading in of Recyclerview items when they first appear as shown in the code below. Perhaps this will be of use to someone.

private final static int FADE_DURATION = 1000; //FADE_DURATION in milliseconds

public void onBindViewHolder(ViewHolder holder, int position) {

    holder.getTextView().setText("some text");

    // Set the view to fade in

private void setFadeAnimation(View view) {
    AlphaAnimation anim = new AlphaAnimation(0.0f, 1.0f);

You can also replace setFadeAnimation() with the following setScaleAnimation() to animate appearance of items by scaling them from a point:

private void setScaleAnimation(View view) {
    ScaleAnimation anim = new ScaleAnimation(0.0f, 1.0f, 0.0f, 1.0f, Animation.RELATIVE_TO_SELF, 0.5f, Animation.RELATIVE_TO_SELF, 0.5f);

The code above has some warts in so far as when you scroll the RecyclerView items always fade or scale. If you wish you can add code to just allow the animation to happen when the fragment or activity containing the RecyclerView is first created (e.g. get the system time on creation and only allow animation for the first FADE_DURATION milliseconds).

Android - drawable with rounded corners at the top only

You may need read this

and below there is a Note.

Note Every corner must (initially) be provided a corner radius greater than 1, or else no corners are rounded. If you want specific corners to not be rounded, a work-around is to use android:radius to set a default corner radius greater than 1, but then override each and every corner with the values you really want, providing zero ("0dp") where you don't want rounded corners.

How can I scan barcodes on iOS?

As with the release of iOS7 you no longer need to use an external framework or library. The iOS ecosystem with AVFoundation now fully supports scanning almost every code from QR over EAN to UPC.

Just have a look at the Tech Note and the AVFoundation programming guide. AVMetadataObjectTypeQRCode is your friend.

Here is a nice tutorial which shows it step by step: iPhone QR code scan library iOS7

Just a little example on how to set it up:

#pragma mark -
#pragma mark AVFoundationScanSetup

- (void) setupScanner;
    self.device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];

    self.input = [AVCaptureDeviceInput deviceInputWithDevice:self.device error:nil];

    self.session = [[AVCaptureSession alloc] init];

    self.output = [[AVCaptureMetadataOutput alloc] init];
    [self.session addOutput:self.output];
    [self.session addInput:self.input];

    [self.output setMetadataObjectsDelegate:self queue:dispatch_get_main_queue()];
    self.output.metadataObjectTypes = @[AVMetadataObjectTypeQRCode];

    self.preview = [AVCaptureVideoPreviewLayer layerWithSession:self.session];
    self.preview.videoGravity = AVLayerVideoGravityResizeAspectFill;
    self.preview.frame = CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height);

    AVCaptureConnection *con = self.preview.connection;

    con.videoOrientation = AVCaptureVideoOrientationLandscapeLeft;

    [self.view.layer insertSublayer:self.preview atIndex:0];

npm install error - unable to get local issuer certificate

There is an issue discussed here which talks about using ca files, but it's a bit beyond my understanding and I'm unsure what to do about it.

This isn't too difficult once you know how! For Windows:

Using Chrome go to the root URL NPM is complaining about (so in your case). Open up dev tools and go to Security-> View Certificate. Check Certification path and make sure your at the top level certificate, if not open that one. Now go to "Details" and export the cert with "Copy to File...".

You need to convert this from DER to PEM. There are several ways to do this, but the easiest way I found was an online tool which should be easy to find with relevant keywords.

Now if you open the key with your favorite text editor you should see




This is the format you need. You can do this for as many keys as you need, and combine them all into one file. I had to do github and the npm registry keys in my case.

Now just edit your .npmrc to point to the file containing your keys like so


I have personally found this to perform significantly better behind our corporate proxy as opposed to the strict-ssl option. YMMV.

Could not locate Gemfile

Make sure you are in the project directory before running bundle install. For example, after running rails new myproject, you will want to cd myproject before running bundle install.

Editing the date formatting of x-axis tick labels in matplotlib

From the package matplotlib.dates as shown in this example the date format can be applied to the axis label and ticks for plot.

Below I have given an example for labeling axis ticks for multiplots

import matplotlib.pyplot as plt
import matplotlib.dates as mdates
import pandas as pd

df = pd.read_csv('US_temp.csv')
plt.plot(df['Date'],df_f['MINT'],label='Min Temp.')
plt.plot(df['Date'],df_f['MAXT'],label='Max Temp.')
####### Use the below functions #######
dtFmt = mdates.DateFormatter('%b') # define the formatting
plt.gca().xaxis.set_major_formatter(dtFmt) # apply the format to the desired axis

As simple as that

XmlWriter to Write to a String Instead of to a File

Guys don't forget to call xmlWriter.Close() and xmlWriter.Dispose() or else your string won't finish creating. It will just be an empty string

How to make (link)button function as hyperlink?

The best way to accomplish this is by simply adding "href" to the link button like below.

<asp:LinkButton runat="server" id="SomeLinkButton" href="url" CssClass="btn btn-primary btn-sm">Button Text</asp:LinkButton>

Using javascript, or doing this programmatically in the page_load, will work as well but is not the best way to go about doing this.

You will get this result:

<a id="MainContent_ctl00_SomeLinkButton" class="btn btn-primary btn-sm" href="url" href="javascript:__doPostBack(&#39;ctl00$MainContent$ctl00$lSomeLinkButton&#39;,&#39;&#39;)">Button Text</a>

You can also get the same results by using using a regular <a href="" class=""></a>.

How do you change Background for a Button MouseOver in WPF?

A slight more difficult answer that uses ControlTemplate and has an animation effect (adapted from

In your resource dictionary define a control template for your button like this one:

<ControlTemplate TargetType="Button" x:Key="testButtonTemplate2">
    <Border Name="RootElement">
            <SolidColorBrush x:Name="BorderBrush" Color="Black"/>

        <Grid Margin="4" >
                <SolidColorBrush x:Name="ButtonBackground" Color="Aquamarine"/>
            <ContentPresenter HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" VerticalAlignment="{TemplateBinding VerticalContentAlignment}" Margin="4,5,4,4"/>
            <VisualStateGroup x:Name="CommonStates">
                <VisualState x:Name="Normal"/>
                <VisualState x:Name="MouseOver">
                        <ColorAnimation Storyboard.TargetName="ButtonBackground" Storyboard.TargetProperty="Color" To="Red"/>
                <VisualState x:Name="Pressed">
                        <ColorAnimation Storyboard.TargetName="ButtonBackground" Storyboard.TargetProperty="Color" To="Red"/>

in your XAML you can use the template above for your button as below:

Define your button

<Button Template="{StaticResource testButtonTemplate2}" 
HorizontalAlignment="Center" VerticalAlignment="Center" 
Foreground="White">My button</Button>

Hope it helps

Check if Key Exists in NameValueCollection

I don't think any of these answers are quite right/optimal. NameValueCollection not only doesn't distinguish between null values and missing values, it's also case-insensitive with regards to it's keys. Thus, I think a full solution would be:

public static bool ContainsKey(this NameValueCollection @this, string key)
    return @this.Get(key) != null 
        // I'm using Keys instead of AllKeys because AllKeys, being a mutable array,
        // can get out-of-sync if mutated (it weirdly re-syncs when you modify the collection).
        // I'm also not 100% sure that OrdinalIgnoreCase is the right comparer to use here.
        // The MSDN docs only say that the "default" case-insensitive comparer is used
        // but it could be current culture or invariant culture
        || @this.Keys.Cast<string>().Contains(key, StringComparer.OrdinalIgnoreCase);

Setting timezone in Python

It's not an answer, but...

To get datetime components individually, better use datetime.timetuple:

time =
#-> time.struct_time(
#    tm_year=2014, tm_mon=9, tm_mday=7, 
#    tm_hour=2, tm_min=38, tm_sec=5, 
#    tm_wday=6, tm_yday=250, tm_isdst=-1

It's now easy to get the parts:

ts = time.timetuple()

WAMP Server ERROR "Forbidden You don't have permission to access /phpmyadmin/ on this server."

I had done below changes for new phpmyadmin4.0.4 in httpd.conf file

<Directory />
    AllowOverride none
    Require all granted

and phpmyadmin.conf

<Directory "c:/wamp/apps/phpmyadmin4.0.4/">
    Options Indexes FollowSymLinks MultiViews
    AllowOverride all
        Order Allow,Deny
    Allow from all

and restart my server.

How to save traceback / sys.exc_info() values in a variable?

The object can be used as a parameter in Exception.with_traceback() function:

except Exception as e:
    tb = sys.exc_info()

What is the difference between String.slice and String.substring?

Note: if you're in a hurry, and/or looking for short answer scroll to the bottom of the answer, and read the last two lines.if Not in a hurry read the whole thing.

let me start by stating the facts:

Note #1: slice()==substring()

What it does?
The slice() method extracts parts of a string and returns the extracted parts in a new string.
The substr() method extracts parts of a string, beginning at the character at the specified position, and returns the specified number of characters.
The substring() method extracts parts of a string and returns the extracted parts in a new string.
Note #2:slice()==substring()

Changes the Original String?
slice() Doesn't
substr() Doesn't
substring() Doesn't
Note #3:slice()==substring()

Using Negative Numbers as an Argument:
slice() selects characters starting from the end of the string
substr()selects characters starting from the end of the string
substring() Doesn't Perform
Note #3:slice()==substr()

if the First Argument is Greater than the Second:
slice() Doesn't Perform
substr() since the Second Argument is NOT a position, but length value, it will perform as usual, with no problems
substring() will swap the two arguments, and perform as usual

the First Argument:
slice() Required, indicates: Starting Index
substr() Required, indicates: Starting Index
substring() Required, indicates: Starting Index
Note #4:slice()==substr()==substring()

the Second Argument:
slice() Optional, The position (up to, but not including) where to end the extraction
substr() Optional, The number of characters to extract
substring() Optional, The position (up to, but not including) where to end the extraction
Note #5:slice()==substring()

What if the Second Argument is Omitted?
slice() selects all characters from the start-position to the end of the string
substr() selects all characters from the start-position to the end of the string
substring() selects all characters from the start-position to the end of the string
Note #6:slice()==substr()==substring()

so, you can say that there's a difference between slice() and substr(), while substring() is basically a copy of slice().

in Summary:
if you know the index(the position) on which you'll stop (but NOT include), Use slice()
if you know the length of characters to be extracted use substr().

Where is Maven Installed on Ubuntu

I would like to add that .m2 folder a lot of people say it is in your home folder. It is right. But if use maven from ready to go IDE like Spring STS then your .m2 folder is placed in root folder

To access root folder you need to switch to super user account

sudo su

Go to root folder

cd root/

You will find it by

cd -all

php/mySQL on XAMPP: password for phpMyAdmin and mysql_connect different?

You need to change the password directly in the database because at mysql the users and their profiles are saved in the database.

So there are several ways. At phpMyAdmin you simple go to user admin, choose root and change the password.

Python Matplotlib figure title overlaps axes label when using twiny

A temporary solution if you don't want to get into the x, y position of your title.

Following worked for me.

plt.title('Capital Expenditure\n') # Add a next line after your title


Installation Issue with matplotlib Python

Problem Cause

In mac os image rendering back end of matplotlib (what-is-a-backend to render using the API of Cocoa by default). There are Qt4Agg and GTKAgg and as a back-end is not the default. Set the back end of macosx that is differ compare with other windows or linux os.


  • I assume you have installed the pip matplotlib, there is a directory in your root called ~/.matplotlib.
  • Create a file ~/.matplotlib/matplotlibrc there and add the following code: backend: TkAgg

From this link you can try different diagrams.

How do I edit SSIS package files?

Current for 2016 link is

SQL Server Data Tools in Visual Studio 2015 is a modern development tool that you can download for free to build SQL Server relational databases, Azure SQL databases, Integration Services packages, Analysis Services data models, and Reporting Services reports. With SSDT, you can design and deploy any SQL Server content type with the same ease as you would develop an application in Visual Studio. This release supports SQL Server 2016 through SQL Server 2005, and provides the design environment for adding features that are new in SQL Server 2016.

Note that you don't need to have Visual Studio pre-installed. SSDT will install required components of VS, if it is not installed on your machine.

This release supports SQL Server 2016 through SQL Server 2005, and provides the design environment for adding features that are new in SQL Server 2016

Previously included in SQL Server standalone Business Intelligence Studio is not available any more and in last years replaced by SQL Server Data Tools (SSDT) for Visual Studio. See answer

Rename package in Android Studio

The accepted answer didn't work for me. Here's a python script to change the package name directly on the source files.

1 - This script it for python3
2 - Create a backup first
3 - Place on the root folder of the android project you want to change
4 - run `python`
5 - Type the old package name
6 - Type the new package name
7 - Clean and Rebuild on Android Studio
8 - SRC folder names won't be changed but app will work

import os, glob, traceback
from pathlib import Path

def rwf(fp, mode="r", data="" ):
    if mode == "r":
        with open(fp, "r", encoding='utf8') as f:
    elif mode == "w":
        with open(fp, "w", encoding='utf8') as f:

old_pkg = input("Old PKG\n").strip()
new_pkg = input("New PKG\n").strip()

if not old_pkg or not new_pkg:
    exit("Args Missing")

dirname, filename = os.path.split(os.path.abspath(__file__))
file_types = ['xml', 'txt', 'json', 'gradle', 'java']
_fs =  glob.iglob(f"{dirname}/**", recursive=True)
for file_path in _fs:
    ext = Path(file_path).suffix.replace(".", "").lower()
    if os.path.isfile(file_path) and ext in file_types:
            content = rwf(file_path)
            new_content = content.replace(old_pkg, new_pkg)
            rwf(file_path, "w", new_content)

python3 gist

DataGridView AutoFit and Fill

Try doing,

 AutoSizeColumnMode = Fill;

How to use font-awesome icons from node-modules

I came upon this question having a similar problem and thought I would share another solution:

If you are creating a Javascript application, font awesome icons can also be referenced directly through Javascript:

First, do the steps in this guide:

npm install @fortawesome/fontawesome-svg-core

Then inside your javascript:

import { library, icon } from '@fortawesome/fontawesome-svg-core'
import { faStroopwafel } from '@fortawesome/free-solid-svg-icons'


const fontIcon= icon({ prefix: 'fas', iconName: 'stroopwafel' })

After the above steps, you can insert the icon inside an HTML node with:


You can also access the HTML string representing the icon with:


Angular 4/5/6 Global Variables

I use environment for that. It works automatically and you don't have to create new injectable service and most usefull for me, don't need to import via constructor.

1) Create environment variable in your environment.ts

export const environment = {
    // runtime variables
    isContentLoading: false,
    isDeployNeeded: false

2) Import environment.ts in *.ts file and create public variable (i.e. "env") to be able to use in html template

import { environment } from 'environments/environment';

export class TestComponent {
    env = environment;

3) Use it in template...

<app-spinner *ngIf='env.isContentLoading'></app-spinner>

in *.ts ...

env.isContentLoading = false 

(or just environment.isContentLoading in case you don't need it for template)

You can create your own set of globals within environment.ts like so:

export const globals = {
    isContentLoading: false,
    isDeployNeeded: false

and import directly these variables (y)

How to know Laravel version and where is it defined?

run php artisan --version from your console.

The version string is defined here:

 * The Laravel framework version.
 * @var string
 const VERSION = '5.5-dev';

Making macOS Installer Packages which are Developer ID ready

There is one very interesting application by Stéphane Sudre which does all of this for you, is scriptable / supports building from the command line, has a super nice GUI and is FREE. Sad thing is: it's called "Packages" which makes it impossible to find in google.

I wished I had known about it before I started handcrafting my own scripts.

Packages application screenshot

Installing PIL (Python Imaging Library) in Win7 64 bits, Python 2.6.4

If you installed a win64 python, you need a win64 PIL. The official PIL download site only has win32, as far as I can tell. The win32 installer will not see your 64-bit python installation.

No amount of tinkering with permissions or redistributables will fix this. You could use the win32 python instead (the Win64 python is mutant anyhow; Microsoft decided that C 'long' should be 32 bits in their 64-bit world, so python 'ints' are only 32 bits in Win64 python).

Since sizeof(long)!=sizeof(ptr) in win64, porting C extensions can be problematic, and will not be the same as porting them to linux 64. E.g. it seems that Win64 numpy is experimental/broken whereas linux64 numpy has been fine for years. My recommendation is if you use win64, stick with win32 python. If you want 64-bit python use linux.

how to remove the bold from a headline?

You want font-weight, not text-decoration (along with suitable additional markup, such as <em> or <span>, so you can apply different styling to different parts of the heading)

How can I check if a URL exists via PHP?

function URLIsValid($URL)
    $exists = true;
    $file_headers = @get_headers($URL);
    $InvalidHeaders = array('404', '403', '500');
    foreach($InvalidHeaders as $HeaderVal)
            if(strstr($file_headers[0], $HeaderVal))
                    $exists = false;
    return $exists;

Computed / calculated / virtual / derived columns in PostgreSQL

PostgreSQL 12 supports generated columns:

PostgreSQL 12 Beta 1 Released!

Generated Columns

PostgreSQL 12 allows the creation of generated columns that compute their values with an expression using the contents of other columns. This feature provides stored generated columns, which are computed on inserts and updates and are saved on disk. Virtual generated columns, which are computed only when a column is read as part of a query, are not implemented yet.

Generated Columns

A generated column is a special column that is always computed from other columns. Thus, it is for columns what a view is for tables.

    height_cm numeric,
    height_in numeric GENERATED ALWAYS AS (height_cm * 2.54) STORED

db<>fiddle demo

Find file in directory from command line

locate <file_pattern>

*** find will certainly work, and can target specific directories. However, this command is slower than the locate command. On a Linux OS, each morning a database is constructed that contains a list of all directory and files, and the locate command efficiently searches this database, so if you want to do a search for files that weren't created today, this would be the fastest way to accomplish such a task.

android View not attached to window manager

when you declare activity in the manifest you need android:configChanges="orientation"


<activity android:theme="@android:style/Theme.Light.NoTitleBar" android:configChanges="orientation"  android:label="traducción" android:name=".PantallaTraductorAppActivity"></activity>

What's the difference between "&nbsp;" and " "?

The first is not treated as white space by the HTML parser, the second is. As a result the " " is not guaranteed to showup within certain HTML markup, while the non breakable space will always show up.

How do I set a textbox's value using an anchor with jQuery?

To assign value of a text box whose id is ?textbox? in jQuery please do the following


Merging two CSV files using Python

When I'm working with csv files, I often use the pandas library. It makes things like this very easy. For example:

import pandas as pd

a = pd.read_csv("filea.csv")
b = pd.read_csv("fileb.csv")
b = b.dropna(axis=1)
merged = a.merge(b, on='title')
merged.to_csv("output.csv", index=False)

Some explanation follows. First, we read in the csv files:

>>> a = pd.read_csv("filea.csv")
>>> b = pd.read_csv("fileb.csv")
>>> a
   title  stage    jan    feb
0   darn  3.001  0.421  0.532
1     ok  2.829  1.036  0.751
2  three  1.115  1.146  2.921
>>> b
   title    mar    apr    may       jun  Unnamed: 5
0   darn  0.631  1.321  0.951    1.7510         NaN
1     ok  1.001  0.247  2.456    0.3216         NaN
2  three  0.285  1.283  0.924  956.0000         NaN

and we see there's an extra column of data (note that the first line of fileb.csv -- title,mar,apr,may,jun, -- has an extra comma at the end). We can get rid of that easily enough:

>>> b = b.dropna(axis=1)
>>> b
   title    mar    apr    may       jun
0   darn  0.631  1.321  0.951    1.7510
1     ok  1.001  0.247  2.456    0.3216
2  three  0.285  1.283  0.924  956.0000

Now we can merge a and b on the title column:

>>> merged = a.merge(b, on='title')
>>> merged
   title  stage    jan    feb    mar    apr    may       jun
0   darn  3.001  0.421  0.532  0.631  1.321  0.951    1.7510
1     ok  2.829  1.036  0.751  1.001  0.247  2.456    0.3216
2  three  1.115  1.146  2.921  0.285  1.283  0.924  956.0000

and finally write this out:

>>> merged.to_csv("output.csv", index=False)



How can I create a simple message box in Python?

You can use pyautogui or pymsgbox:

import pyautogui
pyautogui.alert("This is a message box",title="Hello World")

Using pymsgbox is the same as using pyautogui:

import pymsgbox
pymsgbox.alert("This is a message box",title="Hello World")

Why not use Double or Float to represent currency?

Because floats and doubles cannot accurately represent the base 10 multiples that we use for money. This issue isn't just for Java, it's for any programming language that uses base 2 floating-point types.

In base 10, you can write 10.25 as 1025 * 10-2 (an integer times a power of 10). IEEE-754 floating-point numbers are different, but a very simple way to think about them is to multiply by a power of two instead. For instance, you could be looking at 164 * 2-4 (an integer times a power of two), which is also equal to 10.25. That's not how the numbers are represented in memory, but the math implications are the same.

Even in base 10, this notation cannot accurately represent most simple fractions. For instance, you can't represent 1/3: the decimal representation is repeating (0.3333...), so there is no finite integer that you can multiply by a power of 10 to get 1/3. You could settle on a long sequence of 3's and a small exponent, like 333333333 * 10-10, but it is not accurate: if you multiply that by 3, you won't get 1.

However, for the purpose of counting money, at least for countries whose money is valued within an order of magnitude of the US dollar, usually all you need is to be able to store multiples of 10-2, so it doesn't really matter that 1/3 can't be represented.

The problem with floats and doubles is that the vast majority of money-like numbers don't have an exact representation as an integer times a power of 2. In fact, the only multiples of 0.01 between 0 and 1 (which are significant when dealing with money because they're integer cents) that can be represented exactly as an IEEE-754 binary floating-point number are 0, 0.25, 0.5, 0.75 and 1. All the others are off by a small amount. As an analogy to the 0.333333 example, if you take the floating-point value for 0.1 and you multiply it by 10, you won't get 1.

Representing money as a double or float will probably look good at first as the software rounds off the tiny errors, but as you perform more additions, subtractions, multiplications and divisions on inexact numbers, errors will compound and you'll end up with values that are visibly not accurate. This makes floats and doubles inadequate for dealing with money, where perfect accuracy for multiples of base 10 powers is required.

A solution that works in just about any language is to use integers instead, and count cents. For instance, 1025 would be $10.25. Several languages also have built-in types to deal with money. Among others, Java has the BigDecimal class, and C# has the decimal type.

How can I convert spaces to tabs in Vim or Linux?

Linux: with unexpand (and expand)

Here is a very good solution:, mostly because it uses *nix-utilities:

  1. unexpand — spaces -> tabs
  2. expand — tabs -> spaces

Linux: custom script

My original answer

Bash snippet for replacing 4-spaces indentation (there are two {4} in script) with tabs in all .py files in the ./app folder (recursively):

find ./app -iname '*.py' -type f \
    -exec awk -i inplace \
    '{ match($0, /^(( {4})*)(.*?)$/, arr); gsub(/ {4}/, "\t", arr[1]) }; { print arr[1] arr[3] }' {} \; 

It doesn't modify 4-spaces in the middle or at the end.

Was tested under Ubuntu 16.0x and Linux Mint 18

A general tree implementation?

A tree in Python is quite simple. Make a class that has data and a list of children. Each child is an instance of the same class. This is a general n-nary tree.

class Node(object):
    def __init__(self, data): = data
        self.children = []

    def add_child(self, obj):

Then interact:

>>> n = Node(5)
>>> p = Node(6)
>>> q = Node(7)
>>> n.add_child(p)
>>> n.add_child(q)
>>> n.children
[<__main__.Node object at 0x02877FF0>, <__main__.Node object at 0x02877F90>]
>>> for c in n.children:
...   print

This is a very basic skeleton, not abstracted or anything. The actual code will depend on your specific needs - I'm just trying to show that this is very simple in Python.

How to overwrite the output directory in spark

Spark – Overwrite the output directory:

Spark by default doesn’t overwrite the output directory on S3, HDFS, and any other file systems, when you try to write the DataFrame contents to an existing directory, Spark returns runtime error hence. To overcome this Spark provides an enumeration org.apache.spark.sql.SaveMode.Overwrite to overwrite the existing folder.

We need to use this Overwrite as an argument to mode() function of the DataFrameWrite class, for example.

df. write.mode(SaveMode.Overwrite).csv("/tmp/out/foldername")

or you can use the overwrite string.


Besides Overwrite, SaveMode also offers other modes like SaveMode.Append, SaveMode.ErrorIfExists and SaveMode.Ignore

For older versions of Spark, you can use the following to overwrite the output directory with the RDD contents.

sparkConf.set("spark.hadoop.validateOutputSpecs", "false") val sparkContext = SparkContext(sparkConf)

How to darken a background using CSS?

Just add this code to your image css

        /* top, transparent black, faked with gradient */ 
          rgba(0, 0, 0, 0.7), 
          rgba(0, 0, 0, 0.7)
        /* bottom, image */

Reference: linear-gradient() - CSS | MDN

UPDATE: Not all browsers support RGBa, so you should have a 'fallback color'. This color will be most likely be solid (fully opaque) ex:background:rgb(96, 96, 96). Refer to this blog for RGBa browser support.

Open Url in default web browser

You should use Linking.

Example from the docs:

class OpenURLButton extends React.Component {
  static propTypes = { url: React.PropTypes.string };
  handleClick = () => {
    Linking.canOpenURL(this.props.url).then(supported => {
      if (supported) {
      } else {
        console.log("Don't know how to open URI: " + this.props.url);
  render() {
    return (
      <TouchableOpacity onPress={this.handleClick}>
        {" "}
        <View style={styles.button}>
          {" "}<Text style={styles.text}>Open {this.props.url}</Text>{" "}
        {" "}

Here's an example you can try on Expo Snack:

import React, { Component } from 'react';
import { View, StyleSheet, Button, Linking } from 'react-native';
import { Constants } from 'expo';

export default class App extends Component {
  render() {
    return (
      <View style={styles.container}>
       <Button title="Click me" onPress={ ()=>{ Linking.openURL('')}} />

const styles = StyleSheet.create({
  container: {
    flex: 1,
    alignItems: 'center',
    justifyContent: 'center',
    paddingTop: Constants.statusBarHeight,
    backgroundColor: '#ecf0f1',

How to add parameters to a HTTP GET request in Android?

If you have constant URL I recommend use simplified http-request built on apache http.

You can build your client as following:

private filan static HttpRequest<YourResponseType> httpRequest = 

public void send(){
    ResponseHendler<YourResponseType> rh = 
         httpRequest.execute(param1, value1, param2, value2);


public void whenSuccess(ResponseHendler<YourResponseType> rh){
     rh.ifHasContent(content -> // your code);

public void whenSuccess(ResponseHendler<YourResponseType> rh){
   LOGGER.error("Status code: " + rh.getStatusCode() + ", Error msg: " + rh.getErrorText());

Note: There are many useful methods to manipulate your response.

How To Accept a File POST

See the code below, adapted from this article, which demonstrates the simplest example code I could find. It includes both file and memory (faster) uploads.

public HttpResponseMessage Post()
    var httpRequest = HttpContext.Current.Request;
    if (httpRequest.Files.Count < 1)
        return Request.CreateResponse(HttpStatusCode.BadRequest);

    foreach(string file in httpRequest.Files)
        var postedFile = httpRequest.Files[file];
        var filePath = HttpContext.Current.Server.MapPath("~/" + postedFile.FileName);
        // NOTE: To store in memory use postedFile.InputStream

    return Request.CreateResponse(HttpStatusCode.Created);

jQuery UI autocomplete with JSON

You need to transform the object you are getting back into an array in the format that jQueryUI expects.

You can use $.map to transform the dealers object into that array.

    source: function (request, response) {
        $.getJSON("/example/location/example.json?term=" + request.term, function (data) {
            response($.map(data.dealers, function (value, key) {
                return {
                    label: value,
                    value: key
    minLength: 2,
    delay: 100

Note that when you select an item, the "key" will be placed in the text box. You can change this by tweaking the label and value properties that $.map's callback function return.

Alternatively, if you have access to the server-side code that is generating the JSON, you could change the way the data is returned. As long as the data:

  • Is an array of objects that have a label property, a value property, or both, or
  • Is a simple array of strings

In other words, if you can format the data like this:

[{ value: "1463", label: "dealer 5"}, { value: "269", label: "dealer 6" }]

or this:

["dealer 5", "dealer 6"]

Then your JavaScript becomes much simpler:

    source: "/example/location/example.json"

Fitting a density curve to a histogram in R

Dirk has explained how to plot the density function over the histogram. But sometimes you might want to go with the stronger assumption of a skewed normal distribution and plot that instead of density. You can estimate the parameters of the distribution and plot it using the sn package:

> sn.mle(y=c(rep(65, times=5), rep(25, times=5), rep(35, times=10), rep(45, times=4)))
sn.mle(y = c(rep(65, times = 5), rep(25, times = 5), rep(35, 
    times = 10), rep(45, times = 4)))

    mean     s.d. skewness 
41.46228 12.47892  0.99527 

Skew-normal distributed data plot

This probably works better on data that is more skew-normal:

Another skew-normal plot

What is the right way to POST multipart/form-data using curl?

This is what worked for me

curl --form file='@filename' URL

It seems when I gave this answer (4+ years ago), I didn't really understand the question, or how form fields worked. I was just answering based on what I had tried in a difference scenario, and it worked for me.

So firstly, the only mistake the OP made was in not using the @ symbol before the file name. Secondly, my answer which uses file=... only worked for me because the form field I was trying to do the upload for was called file. If your form field is called something else, use that name instead.


From the curl manpages; under the description for the option --form it says:

This enables uploading of binary files etc. To force the 'content' part to be a file, prefix the file name with an @ sign. To just get the content part from a file, prefix the file name with the symbol <. The difference between @ and < is then that @ makes a file get attached in the post as a file upload, while the < makes a text field and just get the contents for that text field from a file.

Chances are that if you are trying to do a form upload, you will most likely want to use the @ prefix to upload the file rather than < which uploads the contents of the file.


Now I must also add that one must be careful with using the < symbol because in most unix shells, < is the input redirection symbol [which coincidentally will also supply the contents of the given file to the command standard input of the program before <]. This means that if you do not properly escape that symbol or wrap it in quotes, you may find that your curl command does not behave the way you expect.

On that same note, I will also recommend quoting the @ symbol.

You may also be interested in this other question titled: application/x-www-form-urlencoded or multipart/form-data?

I say this because curl offers other ways of uploading a file, but they differ in the content-type set in the header. For example the --data option offers a similar mechanism for uploading files as data, but uses a different content-type for the upload.

Anyways that's all I wanted to say about this answer since it started to get more upvotes. I hope this helps erase any confusions such as the difference between this answer and the accepted answer. There is really none, except for this explanation.

Disabling right click on images using jquery

what is your purpose of disabling the right click. problem with any technique is that there is always a way to go around them. the console for firefox (firebug) and chrome allow for unbinding of that event. or if you want the image to be protected one could always just take a look at their temporary cache for the images.

If you want to create your own contextual menu the preventDefault is fine. Just pick your battles here. not even a big JavaScript library like tnyMCE works on all browsers... and that is not because it's not possible ;-).


Personally I'm more in for an open internet. Native browser behavior should not be hindered by the pages interactions. I am sure that other ways can be found to interact that are not the right click.

How to determine when Fragment becomes visible in ViewPager

We have a special case with MVP where the fragment needs to notify the presenter that the view has become visible, and the presenter is injected by Dagger in fragment.onAttach().

setUserVisibleHint() is not enough, we've detected 3 different cases that needed to be addressed (onAttach() is mentioned so that you know when the presenter is available):

  1. Fragment has just been created. The system makes the following calls:

    setUserVisibleHint() // before fragment's lifecycle calls, so presenter is null
  2. Fragment already created and home button is pressed. When restoring the app to foreground, this is called:

  3. Orientation change:

    onAttach() // presenter available

We only want the visibility hint to get to the presenter once, so this is how we do it:

public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    View root = inflater.inflate(R.layout.fragment_list, container, false);

    if (savedInstanceState != null) {
        lastOrientation = savedInstanceState.getInt(STATE_LAST_ORIENTATION,
    } else {
        lastOrientation = getResources().getConfiguration().orientation;

    return root;

public void onResume() {

    int orientation = getResources().getConfiguration().orientation;
    if (orientation == lastOrientation) {
        if (getUserVisibleHint()) {
    lastOrientation = orientation;

public void setUserVisibleHint(boolean isVisibleToUser) {
    if (presenter != null && isResumed() && isVisibleToUser) {

@Override public void onSaveInstanceState(Bundle outState) {
    outState.putInt(STATE_LAST_ORIENTATION, lastOrientation);

git stash and git pull

When you have changes on your working copy, from command line do:

git stash 

This will stash your changes and clear your status report

git pull

This will pull changes from upstream branch. Make sure it says fast-forward in the report. If it doesn't, you are probably doing an unintended merge

git stash pop

This will apply stashed changes back to working copy and remove the changes from stash unless you have conflicts. In the case of conflict, they will stay in stash so you can start over if needed.

if you need to see what is in your stash

git stash list

TypeError: Missing 1 required positional argument: 'self'

The self keyword in Python is analogous to this keyword in C++ / Java / C#.

In Python 2 it is done implicitly by the compiler (yes Python does compilation internally). It's just that in Python 3 you need to mention it explicitly in the constructor and member functions. example:

 class Pump():
 //member variable

   // constructor
   def __init__(self,ah,bal):
   |    self.account_holder = ah
   |    self.balance_amount = bal

   def getPumps(self):
   |    print("The details of your account are:"+self.account_number + self.balance_amount)

 //object = class(*passing values to constructor*)
 p = Pump("Tahir",12000)

Check for special characters (/*-+_@&$#%) in a string?

Try this way.

public static bool hasSpecialChar(string input)
        string specialChar = @"\|!#$%&/()=?»«@£§€{}.-;'<>_,";
        foreach (var item in specialChar)
            if (input.Contains(item)) return true;

        return false;

Displaying all table names in php from MySQL database

Sure you can query your Database with SHOW TABLES and then loop through all the records but that is extra code lines and work.

PHP has a built in function to list all tables into an array for you :

mysql_list_tables - you can find more information about it at The PHP API page

Excel: Use a cell value as a parameter for a SQL query

If you are using microsoft query, you can add "?" to your query...

select name from user where id= ?

that will popup a small window asking for the cell/data/etc when you go back to excel.

In the popup window, you can also select "always use this cell as a parameter" eliminating the need to define that cell every time you refresh your data. This is the easiest option.

Why is division in Ruby returning an integer instead of decimal value?

There is also the Numeric#fdiv method which you can use instead:

9.fdiv(5)  #=> 1.8

How to check if input date is equal to today's date?

The following solution compares the timestamp integer divided by the values of hours, minutes, seconds, millis.

var reducedToDay = function(date){return ~~(date.getTime()/(1000*60*60*24));};
return reducedToDay(date1) == reducedToDay(date2)

The tilde truncs the division result (see this article about integer division)

How can I pass a parameter to a Java Thread?

No you can't pass parameters to the run() method. The signature tells you that (it has no parameters). Probably the easiest way to do this would be to use a purpose-built object that takes a parameter in the constructor and stores it in a final variable:

public class WorkingTask implements Runnable
    private final Object toWorkWith;

    public WorkingTask(Object workOnMe)
        toWorkWith = workOnMe;

    public void run()
        //do work

Thread t = new Thread(new WorkingTask(theData));

Once you do that - you have to be careful of the data integrity of the object you pass into the 'WorkingTask'. The data will now exist in two different threads so you have to make sure it is Thread Safe.

Converting cv::Mat to IplImage*

cv::Mat is the new type introduce in OpenCV2.X while the IplImage* is the "legacy" image structure.

Although, cv::Mat does support the usage of IplImage in the constructor parameters, the default library does not provide function for the other way. You will need to extract the image header information manually. (Do remember that you need to allocate the IplImage structure, which is lack in your example).

TypeError: 'tuple' object does not support item assignment when swapping values

Evaluating "1,2,3" results in (1, 2, 3), a tuple. As you've discovered, tuples are immutable. Convert to a list before processing.

Convert and format a Date in JSP

In JSP, you'd normally like to use JSTL <fmt:formatDate> for this. You can of course also throw in a scriptlet with SimpleDateFormat, but scriptlets are strongly discouraged since 2003.

Assuming that ${} returns java.util.Date, here's how you can use it:

<%@ taglib prefix="fmt" uri="" %>
<fmt:formatDate value="${}" pattern="yyyy-MM-dd HH:mm:ss" />

If you're actually using a java.util.Calendar, then you can invoke its getTime() method to get a java.util.Date out of it that <fmt:formatDate> accepts:

<fmt:formatDate value="${bean.calendar.time}" pattern="yyyy-MM-dd HH:mm:ss" />

Or, if you're actually holding the date in a java.lang.String (this indicates a serious design mistake in the model; you should really fix your model to store dates as java.util.Date instead of as java.lang.String!), here's how you can convert from one date string format e.g. MM/dd/yyyy to another date string format e.g. yyyy-MM-dd with help of JSTL <fmt:parseDate>.

<fmt:parseDate pattern="MM/dd/yyyy" value="${bean.dateString}" var="parsedDate" />
<fmt:formatDate value="${parsedDate}" pattern="yyyy-MM-dd" />

How to show imageView full screen on imageView click?

<RelativeLayout xmlns:android=""

and in activity

 final ImageView imageView = (ImageView) itemView.findViewById(;          

        PhotoViewAttacher photoAttacher;
        photoAttacher= new PhotoViewAttacher(imageView);


Thats it!

Settings to Windows Firewall to allow Docker for Windows to share drive

My G drive stopped being shared with Docker after a recent Windows 10 update. I was getting the same problem saying it was blocked by the Windows firewall when attempting to reshare it.

Then I had tried to solve this issues by couple of suggestion but i cant resolve that issue after that I have tried to Reset credentials below of Shared Drives and my issue was solved.

So If you want then you can try to do this-

enter image description here

Setting the Vim background colors

In a terminal emulator like konsole or gnome-terminal, you should to set a 256 color setting for vim.

:set  t_Co=256

After that you can to change your background.

Why won't bundler install JSON gem?

I found the solution here. There is a problem with json version 1.8.1 and ruby 2.2.3, so install json 1.8.3 version.

gem install json -v1.8.3

How does inline Javascript (in HTML) work?

The best way to answer your question is to see it in action.

<a id="test" onclick="alert('test')"> test </a> ?

In the js

var test = document.getElementById('test');
console.log( test.onclick ); 

As you see in the console, if you're using chrome it prints an anonymous function with the event object passed in, although it's a little different in IE.

function onclick(event) {

I agree with some of your points about inline event handlers. Yes they are easy to write, but i don't agree with your point about having to change code in multiple places, if you structure your code well, you shouldn't need to do this.

lambda expression join multiple tables with select and where clause

If I understand your questions correctly, all you need to do is add the .Where(m => m.r.u.UserId == 1):

    var UserInRole = db.UserProfiles.
        Join(db.UsersInRoles, u => u.UserId, uir => uir.UserId,
        (u, uir) => new { u, uir }).
        Join(db.Roles, r => r.uir.RoleId, ro => ro.RoleId, (r, ro) => new { r, ro })
        .Where(m => m.r.u.UserId == 1)
        .Select (m => new AddUserToRole
            UserName = m.r.u.UserName,
            RoleName =

Hope that helps.

How to download a file from a URL in C#?

using (var client = new WebClient())
    client.DownloadFile("", "a.mpeg");

How can I search Git branches for a file or directory?

git log + git branch will find it for you:

% git log --all -- somefile

commit 55d2069a092e07c56a6b4d321509ba7620664c63
Author: Dustin Sallings <[email protected]>
Date:   Tue Dec 16 14:16:22 2008 -0800

    added somefile

% git branch -a --contains 55d2069

Supports globbing, too:

% git log --all -- '**/my_file.png'

The single quotes are necessary (at least if using the Bash shell) so the shell passes the glob pattern to git unchanged, instead of expanding it (just like with Unix find).

Python main call within class

Remember, you are NOT allowed to do this.

class foo():
    def print_hello(self):
        print("Hello")       # This next line will produce an ERROR!
    self.print_hello()       # <---- it calls a class function, inside a class,
                             # but outside a class function. Not allowed.

You must call a class function from either outside the class, or from within a function in that class.

Return value from exec(@sql)

On the one hand you could use sp_executesql:

exec sp_executesql N'select @rowcount=count(*) from anytable', 
                    N'@rowcount int output', @rowcount output;

On the other hand you could use a temporary table:

declare @result table ([rowcount] int);
insert into @result ([rowcount])
exec (N'select count(*) from anytable');
declare @rowcount int = (select top (1) [rowcount] from @result);

How to suppress Update Links warning?

Open the VBA Editor of Excel and type this in the Immediate Window (See Screenshot)

Application.AskToUpdateLinks = False 

Close Excel and then open your File. It will not prompt you again. Remember to reset it when you close the workbook else it will not work for other workbooks as well.


enter image description here


So applying it to your code, your code will look like this

Function getWorkbook(bkPath As String) As Workbook
    Application.AskToUpdateLinks = False
    Set getWorkbook = Workbooks.Open(bkPath, False)
    Application.AskToUpdateLinks = True
End Function


Sigil, The code below works on files with broken links as well. Here is my test code.

Test Conditions

  1. Create 2 new files. Name them Sample1.xlsx and Sample2.xlsx and save them on C:\
  2. In cell A1 of Sample1.xlsx, type this formula ='C:\[Sample2.xlsx]Sheet1'!$A$1
  3. Save and close both the files
  4. Delete Sample2.xlsx!!!
  5. Open a New workbook and it's module paste this code and run Sample. You will notice that you will not get a prompt.


Option Explicit

Sub Sample()
    getWorkbook "c:\Sample1.xlsx"
End Sub

Function getWorkbook(bkPath As String) As Workbook
    Application.AskToUpdateLinks = False
    Set getWorkbook = Workbooks.Open(bkPath, False)
    Application.AskToUpdateLinks = True
End Function

Pip - Fatal error in launcher: Unable to create process using '"'

Yes, you need to update the Python version manually.

How to put a horizontal divisor line between edit text's in a activity

For only one line, you need

<View android:id="@+id/primerdivisor"
android:background="#ffffff" /> 

Can I change the checkbox size using CSS?

It's a little ugly (due to the scaling up), but it works on most newer browsers:

  /* Double-sized Checkboxes */_x000D_
  -ms-transform: scale(2); /* IE */_x000D_
  -moz-transform: scale(2); /* FF */_x000D_
  -webkit-transform: scale(2); /* Safari and Chrome */_x000D_
  -o-transform: scale(2); /* Opera */_x000D_
  transform: scale(2);_x000D_
  padding: 10px;_x000D_
/* Might want to wrap a span around your checkbox text */_x000D_
  /* Checkbox text */_x000D_
  font-size: 110%;_x000D_
  display: inline;_x000D_
<input  type="checkbox" name="optiona" id="opta" checked />_x000D_
<span class="checkboxtext">_x000D_
  Option A_x000D_
<input type="checkbox" name="optionb" id="optb" />_x000D_
<span class="checkboxtext">_x000D_
  Option B_x000D_
<input type="checkbox" name="optionc" id="optc" />_x000D_
<span class="checkboxtext">_x000D_
  Option C_x000D_

How to get dictionary values as a generic list

Use this:

List<MyType> items = new List<MyType>()
foreach(var value in myDico.Values)

The problem is that every key in your dictionary has a list of instances as value. Your code would work, if each key would have exactly one instance as value, as in the following example:

Dictionary<string, MyType> myDico = GetDictionary();
List<MyType> items = new List<MyType>(myDico.Values);

How is using OnClickListener interface different via XML and Java code?

These are exactly the same. android:onClick was added in API level 4 to make it easier, more Javascript-web-like, and drive everything from the XML. What it does internally is add an OnClickListener on the Button, which calls your DoIt method.

Here is what using a android:onClick="DoIt" does internally:

Button button= (Button) findViewById(;
button.setOnClickListener(new View.OnClickListener() {
    public void onClick(View v) {

The only thing you trade off by using android:onClick, as usual with XML configuration, is that it becomes a bit more difficult to add dynamic content (programatically, you could decide to add one listener or another depending on your variables). But this is easily defeated by adding your test within the DoIt method.

HttpRequest maximum allowable size in tomcat?

The connector section has the parameter


The maximum size in bytes of the POST which will be handled by the container FORM URL parameter parsing. The limit can be disabled by setting this attribute to a value less than or equal to 0. If not specified, this attribute is set to 2097152 (2 megabytes).

Another Limit is:

maxHttpHeaderSize The maximum size of the request and response HTTP header, specified in bytes. If not specified, this attribute is set to 4096 (4 KB).

You find them in


When to use the different log levels

My two cents about FATAL and TRACE error log levels.

ERROR is when some FAULT (exception) occur.

FATAL is actually DOUBLE FAULT: when exception occur while handling exception.

It's easy to understand for web service.

  1. Request come. Event is logged as INFO
  2. System detects low disk space. Event is logged as WARN
  3. Some function is called to handle the request. While processing division by zero occur. Event is logged as ERROR
  4. Web service's exception handler is called to handle division by zero. Web service/framework is going to send email, but it can not because mailing service is offline now. This second exception can not be handled normally, because Web service's exception handler can not process exception.
  5. Different exception handler called. Event is logged as FATAL

TRACE is when we can trace function entry/exit. This is not about logging, because this message can be generated by some debugger and your code has not call to log at all. So messages that are not from your application are marked like TRACE level. For example your run your application by with strace

So generally in your program you do DEBUG, INFO and WARN logging. And only if you are writing some web service/framework you will use FATAL. And when you are debugging application you will get TRACE logging from this type of software.

How to select a specific node with LINQ-to-XML

Assuming the ID is unique:

var result = xmldoc.Element("Customers")
                   .Single(x => (int?)x.Attribute("ID") == 2);

You could also use First, FirstOrDefault, SingleOrDefault or Where, instead of Single for different circumstances.

How to restrict the selectable date ranges in Bootstrap Datepicker?

The example above can be simplify a bit. Additionally you can put date manually from keyboard instead of selecting it via datepicker only. When clearing the value you need to handle also 'on clearDate' action to remove startDate/endDate boundary:

JS file:

    format: 'yyyy-mm-dd',
    autoclose: true,
}).on('changeDate', function (selected) {
    var startDate = new Date(;
    $('.to_date').datepicker('setStartDate', startDate);
}).on('clearDate', function (selected) {
    $('.to_date').datepicker('setStartDate', null);

    format: 'yyyy-mm-dd',
    autoclose: true,
}).on('changeDate', function (selected) {
    var endDate = new Date(;
    $('.from_date').datepicker('setEndDate', endDate);
}).on('clearDate', function (selected) {
    $('.from_date').datepicker('setEndDate', null);


<input class="from_date" placeholder="Select start date" type="text" name="from_date">
<input class="to_date" placeholder="Select end date" type="text" name="to_date">

Image is not showing in browser?

I had same kind of problem in Netbeans.

I updated the image location in the project and when I executed the jsp file, the image was not loaded in the page.

Then I clean and Built the project in Netbeans. Then it worked fine.

Though you need to check the image actually exists or not using the image URL in the browser.

How to make an element width: 100% minus padding?

Assuming i'm in a container with 15px padding, this is what i always use for the inner part:


That will stretch the inner part to whatever width it should be less the 15px either side.

A Simple, 2d cross-platform graphics library for c or c++?

What about SDL?

Perhaps it's a bit too complex for your needs, but it's certainly cross-platform.

top nav bar blocking top content of the page

Add this:

.navbar {
  position: relative;

Changing route doesn't scroll to top in the new page

None of the answer provided solved my issue. I am using an animation between views and the scrolling would always happen after the animation. The solution I found so that the scrolling to the top happen before the animation is the following directive:

yourModule.directive('scrollToTopBeforeAnimation', ['$animate', function ($animate) {
    return {
        restrict: 'A',
        link: function ($scope, element) {
            $animate.on('enter', element, function (element, phase) {

                if (phase === 'start') {

                    window.scrollTo(0, 0);


I inserted it on my view as follows:

<div scroll-to-top-before-animation>
    <div ng-view class="view-animation"></div>

How to maintain aspect ratio using HTML IMG tag

Set width and height of the images to auto, but limit both max-width and max-height:

img {


If you want to display images of arbitrary size in the 64x64px "frames", you can use inline-block wrappers and positioning for them, like in this fiddle.

Cleaning `Inf` values from an R dataframe

Here is a dplyr/tidyverse solution using the na_if() function:

dat %>% mutate_if(is.numeric, list(~na_if(., Inf)))

Note that this only replaces positive infinity with NA. Need to repeat if negative infinity values also need to be replaced.

dat %>% mutate_if(is.numeric, list(~na_if(., Inf))) %>% 
  mutate_if(is.numeric, list(~na_if(., -Inf)))

Could not find a version that satisfies the requirement tensorflow

I installed it successfully by pip install

JS regex: replace all digits in string

The /g modifier is used to perform a global match (find all matches rather than stopping after the first)

You can use \d for digit, as it is shorter than [0-9].


var s = "04.07.2012"; 
echo(s.replace(/\d/g, "X"));



Eventviewer eventid for lock and unlock

To identify unlock screen I believe that you can use ID 4624. But then you also need to look at the Logon Type which in this case is 7:

Event ID for Logoff is 4634

Setting session variable using javascript

It is very important to understand both sessionStorage and localStorage as they both have different uses:

From MDN:

All of your web storage data is contained within two object-like structures inside the browser: sessionStorage and localStorage. The first one persists data for as long as the browser is open (the data is lost when the browser is closed) and the second one persists data even after the browser is closed and then opened again.

sessionStorage - Saves data until the browser is closed, the data is deleted when the tab/browser is closed.

localStorage - Saves data "forever" even after the browser is closed BUT you shouldn't count on the data you store to be there later, the data might get deleted by the browser at any time because of pretty much anything, or deleted by the user, best practice would be to validate that the data is there first, and continue the rest if it is there. (or set it up again if its not there)

To understand more, read here: localStorage | sessionStorage

How do I pass multiple attributes into an Angular.js attribute directive?

You do it exactly the same way as you would with an element directive. You will have them in the attrs object, my sample has them two-way binding via the isolate scope but that's not required. If you're using an isolated scope you can access the attributes with scope.$eval(attrs.sample) or simply scope.sample, but they may not be defined at linking depending on your situation.

app.directive('sample', function () {
    return {
        restrict: 'A',
        scope: {
            'sample' : '=',
            'another' : '='
        link: function (scope, element, attrs) {
            scope.$watch('sample', function (newVal) {
                console.log('sample', newVal);
            scope.$watch('another', function (newVal) {
                console.log('another', newVal);

used as:

<input type="text" ng-model="name" placeholder="Enter a name here">
<input type="text" ng-model="something" placeholder="Enter something here">
<div sample="name" another="something"></div>

Polymorphism vs Overriding vs Overloading

Polymorphism simply means "Many Forms".

It does not REQUIRE inheritance to interface implementation, which is not inheritance at all, serves polymorphic needs. Arguably, interface implementation serves polymorphic needs "Better" than inheritance.

For example, would you create a super-class to describe all things that can fly? I should think not. You would be be best served to create an interface that describes flight and leave it at that.

So, since interfaces describe behavior, and method names describe behavior (to the programmer), it is not too far of a stretch to consider method overloading as a lesser form of polymorphism.

How to check if a service is running on Android?

The response of geekQ but in Kotlin class. Thanks geekQ

fun isMyServiceRunning(serviceClass : Class<*> ) : Boolean{
    var manager = getSystemService(Context.ACTIVITY_SERVICE) as ActivityManager
    for (service in manager.getRunningServices(Integer.MAX_VALUE)) {
        if ( {
            return true
    return false

The call


How do I compare if a string is not equal to?

Either != or ne will work, but you need to get the accessor syntax and nested quotes sorted out.

<c:if test="${ ne 'MCE'}">
    <%-- snip --%>

Unzipping files in Python

zipfile is a somewhat low-level library. Unless you need the specifics that it provides, you can get away with shutil's higher-level functions make_archive and unpack_archive.

make_archive is already described in this answer. As for unpack_archive:

import shutil
shutil.unpack_archive(filename, extract_dir)

unpack_archive detects the compression format automatically from the "extension" of filename (.zip, .tar.gz, etc), and so does make_archive. Also, filename and extract_dir can be any path-like objects (e.g. pathlib.Path instances) since Python 3.7.

How do I clear inner HTML

The problem appears to be that the global symbol clear is already in use and your function doesn't succeed in overriding it. If you change that name to something else (I used blah), it works just fine:

Live: Version using clear which fails | Version using blah which works

    <h1 onmouseover="go('The dog is in its shed')" onmouseout="blah()">lalala</h1>
    <div id="goy"></div>
    <script type="text/javascript">
    function go(what) {
        document.getElementById("goy").innerHTML = what;
    function blah() {
        document.getElementById("goy").innerHTML = "";

This is a great illustration of the fundamental principal: Avoid global variables wherever possible. The global namespace in browsers is incredibly crowded, and when conflicts occur, you get weird bugs like this.

A corollary to that is to not use old-style onxyz=... attributes to hook up event handlers, because they require globals. Instead, at least use code to hook things up: Live Copy

    <h1 id="the-header">lalala</h1>
    <div id="goy"></div>
    <script type="text/javascript">
      // Scoping function makes the declarations within
      // it *not* globals
        var header = document.getElementById("the-header");
        header.onmouseover = function() {
          go('The dog is in its shed');
        header.onmouseout = clear;

        function go(what) {
          document.getElementById("goy").innerHTML = what;
        function clear() {
          document.getElementById("goy").innerHTML = "";

...and even better, use DOM2's addEventListener (or attachEvent on IE8 and earlier) so you can have multiple handlers for an event on an element.

Passive Link in Angular 2 - <a href=""> equivalent

Updated for Angular2 RC4:

import {HostListener, Directive, Input} from '@angular/core';

    selector: '[href]'
export class PreventDefaultLinkDirective {

    @Input() href;
    @HostListener('click', ['$event']) onClick(event) {this.preventDefault(event);}

    private preventDefault(event) {
        if (this.href.length === 0 || this.href === '#') {


bootstrap(App, [provide(PLATFORM_DIRECTIVES, {useValue: PreventDefaultLinkDirective, multi: true})]);

Simple way to check if a string contains another string in C?

if (strstr(request, "favicon") != NULL) {
    // contains

Span inside anchor or anchor inside span or doesn't matter?

Semantically I think makes more sense as is a container for a single element and if you need to nest them then that suggests more than element will be inside of the outer one.

What is the fastest way to send 100,000 HTTP requests in Python?

This twisted async web client goes pretty fast.


from twisted.internet import reactor
from twisted.internet.defer import Deferred, DeferredList, DeferredLock
from twisted.internet.defer import inlineCallbacks
from twisted.web.client import Agent, HTTPConnectionPool
from twisted.web.http_headers import Headers
from pprint import pprint
from collections import defaultdict
from urlparse import urlparse
from random import randrange
import fileinput

pool = HTTPConnectionPool(reactor)
pool.maxPersistentPerHost = 16
agent = Agent(reactor, pool)
locks = defaultdict(DeferredLock)
codes = {}

def getLock(url, simultaneous = 1):
    return locks[urlparse(url).netloc, randrange(simultaneous)]

def getMapping(url):
    # Limit ourselves to 4 simultaneous connections per host
    # Tweak this number, but it should be no larger than pool.maxPersistentPerHost 
    lock = getLock(url,4)
    yield lock.acquire()
        resp = yield agent.request('HEAD', url)
        codes[url] = resp.code
    except Exception as e:
        codes[url] = str(e)

dl = DeferredList(getMapping(url.strip()) for url in fileinput.input())
dl.addCallback(lambda _: reactor.stop())

How do I set the maximum line length in PyCharm?

For PyCharm 4

File >> Settings >> Editor >> Code Style: Right margin (columns)

suggestion: Take a look at other options in that tab, they're very helpful

How to open a new tab in GNOME Terminal from command line?

A bit more elaborate version (to use from another window):



TERM_PID=$(echo `ps -C gnome-terminal -o pid= | head -1`) # get first gnome-terminal's PID
WID=$(wmctrl -lp | awk -v pid=$TERM_PID '$3==pid{print $1;exit;}') # get window id

xdotool windowfocus $WID
xdotool key alt+t # my key map
xdotool sleep $DELAY # it may take a while to start new shell :(
xdotool type --delay 1 --clearmodifiers "$@"
xdotool key Return

wmctrl -i -a $WID # go to that window (WID is numeric)

# vim:ai
# EOF #

How do I disable TextBox using JavaScript?

Form elements can be accessed via the form's DOM element by name, not by "id" value. Give your form elements names if you want to access them like that, or else access them directly by "id" value:

document.getElementById("color").disabled = true;

edit — oh also, as pointed out by others, it's just "text", not "TextBox", for the "type" attribute.

You might want to invest a little time in reading some front-end development tutorials.

The ResourceConfig instance does not contain any root resource classes

I am new to Jersey - I had the same issue, But when I removed the "/" and just used the @path("admin") it worked.

public class AdminUiResource { ... }

If Else If In a Sql Server Function

ALTER FUNCTION [dbo].[fnTally] (@SchoolId nvarchar(50))
    RETURNS nvarchar(3)

    DECLARE @Final nvarchar(3)
    SELECT @Final = CASE 
        WHEN yes_ans > no_ans  AND yes_ans > na_ans THEN 'Yes'
        WHEN no_ans  > yes_ans AND no_ans  > na_ans THEN 'No'
        WHEN na_ans  > yes_ans AND na_ans  > no_ans THEN 'N/A' END
    FROM dbo.qrc_maintally
    WHERE school_id = @SchoolId

Return @Final

As you can see, this simplifies the code a lot. It also makes other errors in your code more obvious: you're returning an nvarchar, but declared the function to return an int (corrected in the code above).

Android: Go back to previous activity

Just this


On npm install: Unhandled rejection Error: EACCES: permission denied

sudo npm cache clean --force --unsafe-perm

and then npm i goes normally

jQuery add required to input fields

I have found that the following implementations are effective:


$('#freeform_first_name').attr('required', 'required');

These commands (attr, removeAttr, prop) behave differently depending on the version of JQuery you are using. Please reference the documentation here:

How to calculate number of days between two dates

Try this Using moment.js (Its quite easy to compute date operations in javascript)

firstDate.diff(secondDate, 'days', false);// true|false for fraction value

Result will give you number of days in integer.

Using number_format method in Laravel

If you are using Eloquent, in your model put:

public function getPriceAttribute($price)
    return $this->attributes['price'] = sprintf('U$ %s', number_format($price, 2));

Where getPriceAttribute is your field on database. getSomethingAttribute.

How do you get the process ID of a program in Unix or Linux using Python?

Try pgrep. Its output format is much simpler and therefore easier to parse.

How to increase font size in a plot in R?

For completeness, scaling text by 150% with cex = 1.5, here is a full solution:

cex <- 1.5
par(cex.lab=cex, cex.axis=cex, cex.main=cex)
par(cex.lab=1, cex.axis=1, cex.main=1)

I recommend wrapping things like this to reduce boilerplate, e.g.:

plot_cex <- function(x, y, cex=1.5, ...) {
  par(cex.lab=cex, cex.axis=cex, cex.main=cex)
  plot(x, y, ...)
  par(cex.lab=1, cex.axis=1, cex.main=1)

which you can then use like this:

plot_cex(x=1:5, y=rnorm(5), cex=1.3)

The ... are known as ellipses in R and are used to pass additional parameters on to functions. Hence, they are commonly used for plotting. So, the following works as expected:

plot_cex(x=1:5, y=rnorm(5), cex=1.5, ylim=c(-0.5,0.5))

Why do I get a SyntaxError for a Unicode escape in my file path?

f = open('C:\\Users\\Pooja\\Desktop\\trolldata.csv')

Use '\\' for python program in Python version 3 and above.. Error will be resolved..

Get Element value with minidom with Python

It's a tree, and there may be nested elements. Try:

def innerText(self, sep=''):
    t = ""
    for curNode in self.childNodes:
        if (curNode.nodeType == Node.TEXT_NODE):
            t += sep + curNode.nodeValue
        elif (curNode.nodeType == Node.ELEMENT_NODE):
            t += sep + curNode.innerText(sep=sep)
    return t

CSS: borders between table columns only

I used this in a style sheet for three columns separated by vertical borders and it worked fine:

#column-left {
     border-left: 1px solid #dddddd;
#column-center {
     /*no border needed/*
#column-right {
     border-right: 1px solid #dddddd;

The column on the left gets a border on the right, the column on the right gets a border on the left and the the middle column is already taken care of by the left and right.

If your columns are inside a div/wrapper/table/etc... don't forget to add extra space to accomodate the width of the borders.

Quick way to clear all selections on a multiselect enabled <select> with jQuery?

In order to clear all selection, I am using like this and its working fine for me. here is the script:


 $("#ddlMultiselect").multiselect( 'refresh' );

.Net System.Mail.Message adding multiple "To" addresses

private string FormatMultipleEmailAddresses(string emailAddresses)
      var delimiters = new[] { ',', ';' };

      var addresses = emailAddresses.Split(delimiters, StringSplitOptions.RemoveEmptyEntries);

      return string.Join(",", addresses);

Now you can use it like

var mailMessage = new MailMessage();
mailMessage.To.Add(FormatMultipleEmailAddresses("[email protected];[email protected],[email protected]"));

Error: EACCES: permission denied

This command fix the issue. It worked for me:

sudo npm install -g --unsafe-perm=true --allow-root

Handlebars/Mustache - Is there a built in way to loop through the properties of an object?

@Amit's answer is good because it will work in both Mustache and Handlebars.

As far as Handlebars-only solutions, I've seen a few and I like the each_with_key block helper at the best.

  • It allows you to iterate over object literals without having to restructure them first, and
  • It gives you control over what you call the key variable. With many other solutions you have to be careful about using object keys named 'key', or 'property', etc.

How to convert QString to int?

Don't forget to check if the conversion was successful!

bool ok;
auto str= tr("1337");
str.toDouble(&ok); // returns 1337.0, ok set to true
auto strr= tr("LEET");
strr.toDouble(&ok); // returns 0.0, ok set to false

Move div to new line

I've found that you can move div elements to the next line simply by setting the property Display: block;

On each div.

How to increment a letter N times per iteration and store in an array?

Here is your solution for the problem,

$letter = array();
for ($i = 'A'; $i !== 'ZZ'; $i++){
        if(ord($i) % 2 != 0)
           $letter[] .= $i;

You need to get the ASCII value for that character which will solve your problem.

Here is ord doc and working code.

For your requirement, you can do like this,

for ($i = 'A'; $i !== 'ZZ'; ord($i)+$x){
  $letter[] .= $i;

Here set $x as per your requirement.

Why aren't variable-length arrays part of the C++ standard?

There are situations where allocating heap memory is very expensive compared to the operations performed. An example is matrix math. If you work with smallish matrices say 5 to 10 elements and do a lot of arithmetics the malloc overhead will be really significant. At the same time making the size a compile time constant does seem very wasteful and inflexible.

I think that C++ is so unsafe in itself that the argument to "try to not add more unsafe features" is not very strong. On the other hand, as C++ is arguably the most runtime efficient programming language features which makes it more so are always useful: People who write performance critical programs will to a large extent use C++, and they need as much performance as possible. Moving stuff from heap to stack is one such possibility. Reducing the number of heap blocks is another. Allowing VLAs as object members would one way to achieve this. I'm working on such a suggestion. It is a bit complicated to implement, admittedly, but it seems quite doable.

What is the best way to conditionally apply attributes in AngularJS?

Edit: This answer is related to Angular2+! Sorry, I missed the tag!

Original answer:

As for the very simple case when you only want to apply (or set) an attribute if a certain Input value was set, it's as easy as

<my-element [conditionalAttr]="optionalValue || false">

It's the same as:

<my-element [conditionalAttr]="optionalValue ? optionalValue : false">

(So optionalValue is applied if given otherwise the expression is false and attribute is not applied.)

Example: I had the case, where I let apply a color but also arbitrary styles, where the color attribute didn't work as it was already set (even if the @Input() color wasn't given):

  selector: "rb-icon",
  styleUrls: ["icon.component.scss"],
  template: "<span class="ic-{{icon}}" [style.color]="color==color" [ngStyle]="styleObj" ></span>",
export class IconComponent {
   @Input() icon: string;
   @Input() color: string;
   @Input() styles: string;

   private styleObj: object;

So, "style.color" was only set, when the color attribute was there, otherwise the color attribute in the "styles" string could be used.

Of course, this could also be achieved with



@Input color: (string | boolean) = false;

What version of Java is running in Eclipse?

If you want to check if your -vm eclipse.ini option worked correctly you can use this to see under what JVM the IDE itself runs: menu Help > About Eclipse > Installation Details > Configuration tab. Locate the line that says: java.runtime.version=....

The condition has length > 1 and only the first element will be used

Like sgibb said it was an if problem, it had nothing to do with | or ||.

Here is another way to solve your problem:

for (i in 1:nrow(trip)) {
  if(trip$Ref.y[i]=='G' & trip$Variant.y[i]=='T'|trip$Ref.y[i]=='C' & trip$Variant.y[i]=='A') {
    trip[i, 'mutType'] <- "G:C to T:A"
  else if(trip$Ref.y[i]=='G' & trip$Variant.y[i]=='C'|trip$Ref.y[i]=='C' & trip$Variant.y[i]=='G') {
    trip[i, 'mutType'] <- "G:C to C:G"
  else if(trip$Ref.y[i]=='G' & trip$Variant.y[i]=='A'|trip$Ref.y[i]=='C' & trip$Variant.y[i]=='T') {
    trip[i, 'mutType'] <- "G:C to A:T"
  else if(trip$Ref.y[i]=='A' & trip$Variant.y[i]=='T'|trip$Ref.y[i]=='T' & trip$Variant.y[i]=='A') {
    trip[i, 'mutType'] <- "A:T to T:A"
  else if(trip$Ref.y[i]=='A' & trip$Variant.y[i]=='G'|trip$Ref.y[i]=='T' & trip$Variant.y[i]=='C') {
    trip[i, 'mutType'] <- "A:T to G:C"
  else if(trip$Ref.y[i]=='A' & trip$Variant.y[i]=='C'|trip$Ref.y[i]=='T' & trip$Variant.y[i]=='G') {
    trip[i, 'mutType'] <- "A:T to C:G"

What does 'git remote add upstream' help achieve?

I think it could be used for "retroactively forking"

If you have a Git repo, and have now decided that it should have forked another repo. Retroactively you would like it to become a fork, without disrupting the team that uses the repo by needing them to target a new repo.

But I could be wrong.

Best way to parse command line arguments in C#?

Powershell Commandlets.

Parsing done by powershell based on attributes specified on the commandlets, support for validations, parameter sets, pipelining, error reporting, help, and best of all returning .NET objects for use in other commandlets.

A couple links i found helpful getting started:

How to recover just deleted rows in mysql?

There is another solution, if you have binary logs active on your server you can use mysqlbinlog

generate a sql file with it

mysqlbinlog binary_log_file > query_log.sql

then search for your missing rows. If you don't have it active, no other solution. Make backups next time.