Programs & Examples On #Gqlquery

Removing u in list

Please Use map() python function.

Input: In case of list of values

index = [u'CARBO1004' u'CARBO1006' u'CARBO1008' u'CARBO1009' u'CARBO1020']

encoded_string = map(str, index)

Output: ['CARBO1004', 'CARBO1006', 'CARBO1008', 'CARBO1009', 'CARBO1020']

For a Single string input:

index = u'CARBO1004'
# Use Any one of the encoding scheme.
index.encode("utf-8")  # To utf-8 encoding scheme
index.encode('ascii', 'ignore')  # To Ignore Encoding Errors and set to default scheme

Output: 'CARBO1004'

Query for documents where array size is greater than 1

I found this solution, to find items with an array field greater than certain length

  {$project: { count: { $size:"$" }}},

The first $match aggregate uses an argument thats true for all the documents. If blank, i would get

"errmsg" : "exception: The argument to $size must be an Array, but was of type: EOO"

Combine Regexp?

Doesn't contain @: /(^[^@]*$)/

Combining works if the intended result of combination is that any of them matching results in the whole regexp matching.

Send FormData and String Data Together Through JQuery AJAX?

You can try this:

var fd = new FormData();
var data = [];           //<---------------declare array here
var file_data = object.get(0).files[i];
var other_data = $('form').serialize();

data.push(file_data);  //<----------------push the data here
data.push(other_data); //<----------------and this data too

fd.append("file", data);  //<---------then append this data

Regular Expression to get all characters before "-"

Find all word and space characters up to and including a -

^[\w ]+-

Jquery/Ajax call with timer

If you want to set something on a timer, you can use JavaScript's setTimeout or setInterval methods:

setTimeout ( expression, timeout );
setInterval ( expression, interval );

Where expression is a function and timeout and interval are integers in milliseconds. setTimeout runs the timer once and runs the expression once whereas setInterval will run the expression every time the interval passes.

So in your case it would work something like this:

setInterval(function() {
    //call $.ajax here
}, 5000); //5 seconds

As far as the Ajax goes, see jQuery's ajax() method. If you run an interval, there is nothing stopping you from calling the same ajax() from other places in your code.

If what you want is for an interval to run every 30 seconds until a user initiates a form submission...and then create a new interval after that, that is also possible:

setInterval() returns an integer which is the ID of the interval.

var id = setInterval(function() {
    //call $.ajax here
}, 30000); // 30 seconds

If you store that ID in a variable, you can then call clearInterval(id) which will stop the progression.

Then you can reinstantiate the setInterval() call after you've completed your ajax form submission.

Switch php versions on commandline ubuntu 16.04

please follow the steps :

i.e : your current version is : current_version = 7.3 , and you want to change it to : new_version = 7.2

1) sudo a2dismod php(current_version) 
2) sudo a2enmod php(new_version)
3) sudo update-alternatives --config php (here you need to select php version number) 
4) restart apache through : 
  sudo /etc/init.d/apache2 restart OR
  sudo service apache2 restart

Postgresql tables exists, but getting "relation does not exist" when querying

I had to include double quotes with the table name.

db=> \d
                           List of relations
 Schema |                     Name                      | Type  | Owner 
 public | COMMONDATA_NWCG_AGENCIES                      | table | dan

Did not find any relation named "COMMONDATA_NWCG_AGENCIES".


Double quotes:

                         Table "public.COMMONDATA_NWCG_AGENCIES"
          Column          |            Type             | Collation | Nullable | Default 
 ID                       | integer                     |           | not null | 

Lots and lots of double quotes:

db=> select ID from COMMONDATA_NWCG_AGENCIES limit 1;
ERROR:  relation "commondata_nwcg_agencies" does not exist
LINE 1: select ID from COMMONDATA_NWCG_AGENCIES limit 1;
db=> select ID from "COMMONDATA_NWCG_AGENCIES" limit 1;
ERROR:  column "id" does not exist
LINE 1: select ID from "COMMONDATA_NWCG_AGENCIES" limit 1;
db=> select "ID" from "COMMONDATA_NWCG_AGENCIES" limit 1;
(1 row)

This is postgres 11. The CREATE TABLE statements from this dump had double quotes as well:



dynamically set iframe src

try this code. then 'formId' div can set the image.

$('#formId').append('<iframe style="width: 100%;height: 500px" src="/document_path/name.jpg"' +
 'title="description"> </iframe> ');

Is there any method to get the URL without query string?

If you also want to remove hash, try this one: window.location.href.split(/[?#]/)[0]

How to do multiple conditions for single If statement

As Hogan notes above, use an AND instead of &. See this tutorial for more info.

Run php script as daemon process

If you can - grab a copy of Advanced Programming in the UNIX Environment. The entire chapter 13 is devoted to daemon programming. Examples are in C, but all the function you need have wrappers in PHP (basically the pcntl and posix extensions).

In a few words - writing a daemon (this is posible only on *nix based OS-es - Windows uses services) is like this:

  1. Call umask(0) to prevent permission issues.
  2. fork() and have the parent exit.
  3. Call setsid().
  4. Setup signal processing of SIGHUP (usually this is ignored or used to signal the daemon to reload its configuration) and SIGTERM (to tell the process to exit gracefully).
  5. fork() again and have the parent exit.
  6. Change the current working dir with chdir().
  7. fclose() stdin, stdout and stderr and don't write to them. The corrrect way is to redirect those to either /dev/null or a file, but I couldn't find a way to do it in PHP. It is possible when you launch the daemon to redirect them using the shell (you'll have to find out yourself how to do that, I don't know :).
  8. Do your work!

Also, since you are using PHP, be careful for cyclic references, since the PHP garbage collector, prior to PHP 5.3, has no way of collecting those references and the process will memory leak, until it eventually crashes.

Equivalent of *Nix 'which' command in PowerShell?

I like Get-Command | Format-List, or shorter, using aliases for the two and only for powershell.exe:

gcm powershell | fl

You can find aliases like this:

alias -definition Format-List

Tab completion works with gcm.

Remove 'b' character do in front of a string literal in Python 3

Decoding is redundant

You only had this "error" in the first place, because of a misunderstanding of what's happening.

You get the b because you encoded to utf-8 and now it's a bytes object.

 >> type("text".encode("utf-8"))
 >> <class 'bytes'>


  1. You can just print the string first
  2. Redundantly decode it after encoding

Android RecyclerView addition & removal of items

you must to remove this item from arrayList of data

notifyItemRangeChanged(holder.getAdapterPosition(), getItemCount());

Why should C++ programmers minimize use of 'new'?

Because the stack is faster and leak-proof

In C++, it takes but a single instruction to allocate space -- on the stack -- for every local scope object in a given function, and it's impossible to leak any of that memory. That comment intended (or should have intended) to say something like "use the stack and not the heap".

Set focus and cursor to end of text input field / string w. Jquery

You can do this using Input.setSelectionRange, part of the Range API for interacting with text selections and the text cursor:

var searchInput = $('#Search');

// Multiply by 2 to ensure the cursor always ends up at the end;
// Opera sometimes sees a carriage return as 2 characters.
var strLength = searchInput.val().length * 2;

searchInput[0].setSelectionRange(strLength, strLength);

Demo: Fiddle

Is there an XSL "contains" directive?

there is indeed an xpath contains function it should look something like:

<xsl:for-each select="item">
<xsl:variable name="hhref" select="link" />
<xsl:variable name="pdate" select="pubDate" />
<xsl:if test="not(contains(hhref,'1234'))">
    <a href="{$hhref}" title="{$pdate}">
      <xsl:value-of select="title"/>

android listview item height

The trick for me was not setting the height -- but instead setting the minHeight. This must be applied to the root view of whatever layout your custom adapter is using to render each row.

Add Marker function with Google Maps API

<div id="map" style="width:100%;height:500px"></div>

function myMap() {
  var myCenter = new google.maps.LatLng(51.508742,-0.120850);
  var mapCanvas = document.getElementById("map");
  var mapOptions = {center: myCenter, zoom: 5};
  var map = new google.maps.Map(mapCanvas, mapOptions);
  var marker = new google.maps.Marker({position:myCenter});

<script src=""></script>

How to set text size in a button in html

Try this

<input type="submit" 
       style="font-size : 20px; width: 100%; height: 100px;" /> 

MongoDB: How to find out if an array field contains an element?

[edit based on this now being possible in recent versions]

[Updated Answer] You can query the following way to get back the name of class and the student id only if they are already enrolled.

 {_id:0, name:1, students:{$elemMatch:{$eq:ObjectId("51780f796ec4051a536015cf")}}})

and you will get back what you expected:

{ "name" : "CS 101", "students" : [ ObjectId("51780f796ec4051a536015cf") ] }
{ "name" : "Literature" }
{ "name" : "Physics", "students" : [ ObjectId("51780f796ec4051a536015cf") ] }

[Original Answer] It's not possible to do what you want to do currently. This is unfortunate because you would be able to do this if the student was stored in the array as an object. In fact, I'm a little surprised you are using just ObjectId() as that will always require you to look up the students if you want to display a list of students enrolled in a particular course (look up list of Id's first then look up names in the students collection - two queries instead of one!)

If you were storing (as an example) an Id and name in the course array like this:

        "_id" : ObjectId("51780fb5c9c41825e3e21fc6"),
        "name" : "Physics",
        "students" : [
                {id: ObjectId("51780f796ec4051a536015cf"), name: "John"},
                {id: ObjectId("51780f796ec4051a536015d0"), name: "Sam"}

Your query then would simply be:

db.course.find( { }, 
                { students : 
                    { $elemMatch : 
                       { id : ObjectId("51780f796ec4051a536015d0"), 
                         name : "Sam" 

If that student was only enrolled in CS 101 you'd get back:

{ "name" : "Literature" }
{ "name" : "Physics" }
    "name" : "CS 101",
    "students" : [
            "id" : ObjectId("51780f796ec4051a536015cf"),
            "name" : "John"

How do I create a singleton service in Angular 2?

A singleton service is a service for which only one instance exists in an app.

There are (2) ways to provide a singleton service for your application.

  1. use the providedIn property, or

  2. provide the module directly in the AppModule of the application

Using providedIn

Beginning with Angular 6.0, the preferred way to create a singleton service is to set providedIn to root on the service's @Injectable() decorator. This tells Angular to provide the service in the application root.

import { Injectable } from '@angular/core';

  providedIn: 'root',
export class UserService {

NgModule providers array

In apps built with Angular versions prior to 6.0, services are registered NgModule providers arrays as follows:

  providers: [UserService],

If this NgModule were the root AppModule, the UserService would be a singleton and available throughout the app. Though you may see it coded this way, using the providedIn property of the @Injectable() decorator on the service itself is preferable as of Angular 6.0 as it makes your services tree-shakable.

How to decrypt an encrypted Apple iTunes iPhone backup?

You should grab a copy of Erica Sadun's mdhelper command line utility (OS X binary & source). It supports listing and extracting the contents of iPhone/iPod Touch backups, including address book & SMS databases, and other application metadata and settings.

Simple proof that GUID is not unique

If GUID collisions are a concern, I would recommend using the ScottGuID instead.

Laravel Eloquent - distinct() and count() not working properly together

A more generic answer that would have saved me time, and hopefully others:

Does not work (returns count of all rows):


The fix:


Skip first couple of lines while reading lines in Python file

Use a slice, like below:

with open('yourfile.txt') as f:
    lines_after_17 = f.readlines()[17:]

If the file is too big to load in memory:

with open('yourfile.txt') as f:
    for _ in range(17):
    for line in f:
        # do stuff

/bin/sh: pushd: not found

sudo dpkg-reconfigure dash 

Then select no.

Python - 'ascii' codec can't decode byte


encode converts a unicode object to a string object. But here you have invoked it on a string object (because you don't have the u). So python has to convert the string to a unicode object first. So it does the equivalent of


But the decode fails because the string isn't valid ascii. That's why you get a complaint about not being able to decode.

How to use code to open a modal in Angular 2?

Easy way to achieve this in angular 2 or 4 (Assuming that you are using bootstrap 4)


<button type="button" (click)="openModel()">Open Modal</button>_x000D_
<div #myModel class="modal fade">_x000D_
  <div class="modal-dialog">_x000D_
    <div class="modal-content">_x000D_
     <div class="modal-header">_x000D_
        <h5 class="modal-title ">Title</h5>_x000D_
        <button type="button" class="close" (click)="closeModel()">_x000D_
            <span aria-hidden="true">&times;</span>_x000D_
      <div class="modal-body">_x000D_
        <p>Some text in the modal.</p>_x000D_


import {Component, OnInit, ViewChild} from '@angular/core';

@ViewChild('myModal') myModal;

openModel() {
  this.myModal.nativeElement.className = 'modal fade show';
closeModel() {
   this.myModal.nativeElement.className = 'modal hide';

Difference between array_push() and $array[] =

The difference is in the line below to "because in that way there is no overhead of calling a function."

array_push() will raise a warning if the first argument is not an array. This differs from the $var[] behaviour where a new array is created.

Querying DynamoDB by date

Updated Answer There is no convenient way to do this using Dynamo DB Queries with predictable throughput. One (sub optimal) option is to use a GSI with an artificial HashKey & CreatedAt. Then query by HashKey alone and mention ScanIndexForward to order the results. If you can come up with a natural HashKey (say the category of the item etc) then this method is a winner. On the other hand, if you keep the same HashKey for all items, then it will affect the throughput mostly when when your data set grows beyond 10GB (one partition)

Original Answer: You can do this now in DynamoDB by using GSI. Make the "CreatedAt" field as a GSI and issue queries like (GT some_date). Store the date as a number (msecs since epoch) for this kind of queries.

Details are available here: Global Secondary Indexes - Amazon DynamoDB :

This is a very powerful feature. Be aware that the query is limited to (EQ | LE | LT | GE | GT | BEGINS_WITH | BETWEEN) Condition - Amazon DynamoDB :

Running CMD command in PowerShell

One solution would be to pipe your command from PowerShell to CMD. Running the following command will pipe the notepad.exe command over to CMD, which will then open the Notepad application.

PS C:\> "notepad.exe" | cmd

Once the command has run in CMD, you will be returned to a PowerShell prompt, and can continue running your PowerShell script.


CMD's Startup Message is Shown

As mklement0 points out, this method shows CMD's startup message. If you were to copy the output using the method above into another terminal, the startup message will be copied along with it.

How to get raw text from pdf file using java

Extracting all keywords from PDF(from a web page) file on your local machine or Base64 encoded string:

import org.apache.commons.codec.binary.Base64;
import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.text.PDFTextStripper;

import java.util.HashMap;
import java.util.Map;

public class WebPagePdfExtractor {

    public static void main(String arg[]) {
        WebPagePdfExtractor webPagePdfExtractor = new WebPagePdfExtractor();

        System.out.println("From file:   " + webPagePdfExtractor.processRecord(createByteArray()).get("text"));

        System.out.println("From string: " + webPagePdfExtractor.processRecord(getArrayFromBase64EncodedString()).get("text"));

    public Map<String, Object> processRecord(byte[] byteArray) {
        Map<String, Object> map = new HashMap<>();
        try {
            PDFTextStripper stripper = new PDFTextStripper();

            PDDocument document = PDDocument.load(byteArray);
            String text = stripper.getText(document);
            map.put("text", text.replaceAll("\n|\r|\t", " "));
        } catch (Exception exception) {
        return map;

    private static byte[] getArrayFromBase64EncodedString() {
        String encodedContent = "data:application/pdf;base64,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" +
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                "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" +
                "zIFsgMiAwIFIgXSA+PgplbmRvYmoKMTQgMCBvYmoKPDwgL1R5cGUgL0NhdGFsb2cgL1BhZ2VzIDMgMCBSID4+CmVuZG9iago5IDAgb2JqCjw8IC9UeXBlIC9Gb250IC9TdWJ0eXBlIC9UcnVlVHlwZSAvQmFzZUZvbnQgL0NOVFpYVStNZW5" +
                "L0l0YWxpY0FuZ2xlIDAgL0FzY2VudCA5MjggL0Rlc2NlbnQgLTIzNiAvQ2FwSGVpZ2h0IDcyOQovU3RlbVYgOTkgL1hIZWlnaHQgNTQ3…/ZfICj5JcLdi/ATmQZKogDPg0lIDBunI0ZGOB1OB/Lpyce1TbJqCpBThycVs3GyQPZSLKexbMGyFss8LF4sNb2lElu5HPlJ2439G1jKsbRh6cTyPNpx8I6AFxa8P+xD2E4e/G+5PqJ/8aDzERFvGBJR/WLkfwcM3kRCiZpokDMdxhn5MeD9Rn5MSm0mYUpLSF98J5HXaQgtpJvoDWGesEe4C4NgK3woWsQ88RgzszXsMM4WyALeIC5gO5B/FYk/pNxVCJGoZT8NYc8LIknrONeVQYznus51pYeZHCaXw+RYIJLAEogJfMEbVPrvv31S6icvTMlp1EQhO41cOuXb0EEkSYkmGaMXSzuIfhCKAA4Y/YScTs9ASizblWVyWB1UT4fwNfSp9+mgwLFd4oI3D++9++kuheYWpOnEeBhLJrv7kVg" +
                "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" +
                "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" +
                "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" +
                "JTPMvxBMSaYoSmQ+nHtDywiJbzyzTe7xcfDmR5vTBcyPsKv7yBPEyXopGDxCAHOoUoppRILPQiribnP/IqOjlLka3XEo5eIbu8bCTCqRmej6+99ib/lF6im3/13ItnD8OtF4LyxN+YxQq0iwTyqjsx0mwIFVUkLkZSWbX1dmiLORxlVBGTIWSC" +
                "NNE0wTAxNnJCdIHTeHOcTzt1nM80dUbxARJ9r/0+T2BoAA0leOYPHXrlpnIwoYmg8NPdo9LFdJYupavSQ9JD09Xpmtzw3IjcyNyo3OjcmNzY3LhcWzVUi9WsWqpWVYdUh1arqzXecG+EN9Ib5Y32xnhjvXFem5POpPLJEh5Ff6LMf2vVqgwKOx" +
                "IeHbu64vXswkn3v54zdkzOzp2Oubnjy6B7dMEZfqlnubDymyWVX/SsEFbeWCy3YknJ0NxCWddt/CFxKspCjmFZ7tgfY1ibvokegcNxGL9GKZGsUI5imYqJoV/8GMZcsm0pXJhNRtkbfuofdPmBA3IYu/rV+/Oa6I3VNatqa1fVrF7Xc1xSe4um" +
        String content = encodedContent.substring("data:application/pdf;base64," .length());
        return Base64.decodeBase64(content);

    public static byte[] createByteArray() {
        String pathToBinaryData = "/bla-bla/src/main/resources/small.pdf";

        File file = new File(pathToBinaryData);
        if (!file.exists()) {
            System.out.println(" could not be found in folder " + pathToBinaryData);
            return null;

        FileInputStream fin = null;
        try {
            fin = new FileInputStream(file);
        } catch (FileNotFoundException e) {

        byte fileContent[] = new byte[(int) file.length()];

        try {
        } catch (IOException e) {

        return fileContent;

Change collations of all columns of all tables in SQL Server

Fixed length problem nvarchar and added NULL/NOT NULL

DECLARE @collate nvarchar(100);
DECLARE @table nvarchar(255);
DECLARE @column_name nvarchar(255);
DECLARE @column_id int;
DECLARE @data_type nvarchar(255);
DECLARE @max_length int;
DECLARE @row_id int;
DECLARE @sql nvarchar(max);
DECLARE @sql_column nvarchar(max);
DECLARE @is_Nullable bit;
DECLARE @null nvarchar(25);

SET @collate = 'Latin1_General_CI_AS';

DECLARE local_table_cursor CURSOR FOR

SELECT [name]
FROM sysobjects

OPEN local_table_cursor
FETCH NEXT FROM local_table_cursor
INTO @table


    DECLARE local_change_cursor CURSOR FOR

    SELECT ROW_NUMBER() OVER (ORDER BY c.column_id) AS row_id
        , column_name
        , t.Name data_type
        , c.max_length
        , c.column_id
        , c.is_nullable
    FROM sys.columns c
    JOIN sys.types t ON c.system_type_id = t.system_type_id
    LEFT OUTER JOIN sys.index_columns ic ON ic.object_id = c.object_id AND ic.column_id = c.column_id
    LEFT OUTER JOIN sys.indexes i ON ic.object_id = i.object_id AND ic.index_id = i.index_id
    WHERE c.object_id = OBJECT_ID(@table)
    ORDER BY c.column_id

    OPEN local_change_cursor
    FETCH NEXT FROM local_change_cursor
    INTO @row_id, @column_name, @data_type, @max_length, @column_id, @is_nullable


        IF (@max_length = -1) SET @max_length = 4000;
        set @null=' NOT NULL'
        if (@is_nullable = 1) Set @null=' NULL'
        if (@Data_type='nvarchar') set @max_length=cast(@max_length/2 as bigint)
        IF (@data_type LIKE '%char%')
        BEGIN TRY
            SET @sql = 'ALTER TABLE ' + @table + ' ALTER COLUMN [' + rtrim(@column_name) + '] ' + @data_type + '(' + CAST(@max_length AS nvarchar(100)) +  ') COLLATE ' + @collate + @null
            PRINT @sql
            EXEC sp_executesql @sql
        END TRY
          PRINT 'ERROR: Some index or contraint rely on the column ' + @column_name + '. No conversion possible.'
          PRINT @sql
        END CATCH

        FETCH NEXT FROM local_change_cursor
        INTO @row_id, @column_name, @data_type, @max_length, @column_id, @is_Nullable


    CLOSE local_change_cursor
    DEALLOCATE local_change_cursor

    FETCH NEXT FROM local_table_cursor
    INTO @table


CLOSE local_table_cursor
DEALLOCATE local_table_cursor


How to end C++ code

If you have an error somewhere deep in the code, then either throw an exception or set the error code. It's always better to throw an exception instead of setting error codes.

How can I use jQuery to make an input readonly?

These days with jQuery 1.6.1 or above it is recommended that .prop() be used when setting boolean attributes/properties.

$("#fieldName").prop("readonly", true);

Hash String via SHA-256 in Java

return new String(Hex.encode(digest));

Nodemailer with Gmail and NodeJS

It is resolved using nodemailer-smtp-transport module inside createTransport.

var smtpTransport = require('nodemailer-smtp-transport');

var transport = nodemailer.createTransport(smtpTransport({
    service: 'gmail',
    auth: {
        user: '*******',
        pass: '*****password'

Add a summary row with totals

Try to use union all as below

SELECT [Type], [Total Sales] From Before
union all
SELECT 'Total', Sum([Total Sales]) From Before

if you have problem with ordering, as i-one suggested try this:

select [Type], [Total Sales] 
from (SELECT [Type], [Total Sales], 0 [Key] 
      From Before 
      union all 
      SELECT 'Total', Sum([Total Sales]), 1 From Before) sq 
order by [Key], Type

Dynamically changing font size of UILabel

Its a little bit not sophisticated but this should work, for example lets say you want to cap your uilabel to 120x120, with max font size of 28:

magicLabel.numberOfLines = 0;
magicLabel.lineBreakMode = NSLineBreakByWordWrapping;
magicLabel.text = text;
    for (int i = 28; i>3; i--) {
        CGSize size = [text sizeWithFont:[UIFont systemFontOfSize:(CGFloat)i] constrainedToSize:CGSizeMake(120.0f, CGFLOAT_MAX) lineBreakMode:NSLineBreakByWordWrapping];
        if (size.height < 120) {
            magicLabel.font = [UIFont systemFontOfSize:(CGFloat)i];

Using PowerShell to remove lines from a text file if it contains a string

Suppose you want to write that in the same file, you can do as follows:

Set-Content -Path "C:\temp\Newtext.txt" -Value (get-content -Path "c:\Temp\Newtext.txt" | Select-String -Pattern 'H\|159' -NotMatch)

Can I stretch text using CSS?

I'll answer for horizontal stretching of text, since the vertical is the easy part - just use "transform: scaleY()"

.stretched-text {
  letter-spacing: 2px;
  display: inline-block;
  font-size: 32px;
  transform: scaleY(0.5);
  transform-origin: 0 0;
  margin-bottom: -50%;
span {
  font-size: 16px;
  vertical-align: top;
<span class="stretched-text">this is some stretched text</span>
<span>and this is some random<br />triple line <br />not stretched text</span>

letter-spacing just adds space between letters, stretches nothing, but it's kinda relative

inline-block because inline elements are too restrictive and the code below wouldn't work otherwise

Now the combination that makes the difference

font-size to get to the size we want - that way the text will really be of the length it's supposed to be and the text before and after it will appear next to it (scaleX is just for show, the browser still sees the element at its original size when positioning other elements).

scaleY to reduce the height of the text, so that it's the same as the text beside it.

transform-origin to make the text scale from the top of the line.

margin-bottom set to a negative value, so that the next line will not be far below - preferably percentage, so that we won't change the line-height property. vertical-align set to top, to prevent the text before or after from floating to other heights (since the stretched text has a real size of 32px)

-- The simple span element has a font-size, only as a reference.

The question asked for a way to prevent the boldness of the text caused by the stretch and I still haven't given one, BUT the font-weight property has more values than just normal and bold.

I know, you just can't see that, but if you search for the appropriate fonts, you can use the more values.

onclick="location.href='link.html'" does not load page in Safari

I had the same error. Make sure you don't have any <input>, <select>, etc. name="location".

Change Title of Javascript Alert

It's not possible, sorry. If really needed, you could use a jQuery plugin to have a custom alert.

How to deselect a selected UITableView cell?

Swift 4:

tableView.deselectRow(at: indexPath, animated: true)

Diff files present in two different directories

Here is a script to show differences between files in two folders. It works recursively. Change dir1 and dir2.

(search() { for i in $1/*; do [ -f "$i" ] && (diff "$1/${i##*/}" "$2/${i##*/}" || echo "files: $1/${i##*/}   $2/${i##*/}"); [ -d "$i" ] && search "$1/${i##*/}" "$2/${i##*/}"; done }; search "dir1" "dir2" )

Is there a way to 'uniq' by column?

To consider multiple column.

Sort and give unique list based on column 1 and column 3:

sort -u -t : -k 1,1 -k 3,3 test.txt
  • -t : colon is separator
  • -k 1,1 -k 3,3 based on column 1 and column 3

What is the difference between C# and .NET?

C# is a programming language, .NET is a blanket term that tends to cover both the .NET Framework (an application framework library) and the Common Language Runtime which is the runtime in which .NET assemblies are run.

Microsoft's implementation of C# is heavily integrated with the .NET Framework so it is understandable that the two concepts would be confused. However it is important to understand that they are two very different things.

Here is a class written in C#:

class Example { }

Here is a class written in C# that explicitly uses a .NET framework assembly, type, and method:

class Example
    static void Main()
        // Here we call into the .NET framework to 
        // write to the output console
        System.Console.Write("hello, world");

As I mentioned before, it is very difficult to use Microsoft's implementation of C# without using the .NET framework as well. My first Example implementation above even uses the .NET framework (implicitly, yes, but it does use it nonetheless) because Example inherits from System.Object.

Also, the reason I use the phrase Microsoft's implementation of C# is because there are other implementations of C# available.

Regarding C++ Include another class

you need to forward declare the name of the class if you don't want a header:

class ClassTwo;

Important: This only works in some cases, see Als's answer for more information..

jquery - Check for file extension before uploading

Here is a simple code for javascript validation, and after it validates it will clean the input file.

<input type="file" id="image" accept="image/*" onChange="validate(this.value)"/>

function validate(file) {
    var ext = file.split(".");
    ext = ext[ext.length-1].toLowerCase();      
    var arrayExtensions = ["jpg" , "jpeg", "png", "bmp", "gif"];

    if (arrayExtensions.lastIndexOf(ext) == -1) {
        alert("Wrong extension type.");

How to uninstall mini conda? python

If you are using windows, just search for miniconda and you'll find the folder. Go into the folder and you'll find a miniconda uninstall exe file. Run it.

Start / Stop a Windows Service from a non-Administrator user account

Below I have put together everything I learned about Starting/Stopping a Windows Service from a non-Admin user account, if anyone needs to know.

Primarily, there are two ways in which to Start / Stop a Windows Service. 1. Directly accessing the service through logon Windows user account. 2. Accessing the service through IIS using Network Service account.

Command line command to start / stop services:

C:/> net start <SERVICE_NAME>
C:/> net stop <SERVICE_NAME>

C# Code to start / stop services:

ServiceController service = new ServiceController(SERVICE_NAME);

//Start the service
if (service.Status == ServiceControllerStatus.Stopped)
      service.WaitForStatus(ServiceControllerStatus.Running, TimeSpan.FromSeconds(10.0));

//Stop the service
if (service.Status == ServiceControllerStatus.Running)
      service.WaitForStatus(ServiceControllerStatus.Stopped, TimeSpan.FromSeconds(10.0));

Note 1: When accessing the service through IIS, create a Visual Studio C# ASP.NET Web Application and put the code in there. Deploy the WebService to IIS Root Folder (C:\inetpub\wwwroot\) and you're good to go. Access it by the url http:///.

1. Direct Access Method

If the Windows User Account from which either you give the command or run the code is a non-Admin account, then you need to set the privileges to that particular user account so it has the ability to start and stop Windows Services. This is how you do it. Login to an Administrator account on the computer which has the non-Admin account from which you want to Start/Stop the service. Open up the command prompt and give the following command:

C:/>sc sdshow <SERVICE_NAME>

Output of this will be something like this:


It lists all the permissions each User / Group on this computer has with regards to .

A description of one part of above command is as follows:


It has the default owner, default group, and it has the Security descriptor control flags (A;;CCLCSWRPWPDTLOCRRC;;;SY):

ace_flags - n/a,
rights - CCLCSWRPWPDTLOCRRC,  please refer to the Access Rights and Access Masks and Directory Services Access Rights
CC: ADS_RIGHT_DS_CREATE_CHILD - Create a child DS object.
LC: ADS_RIGHT_ACTRL_DS_LIST - Enumerate a DS object.
SW: ADS_RIGHT_DS_SELF - Access allowed only after validated rights checks supported by the object are performed. This flag can be used alone to perform all validated rights checks of the object or it can be combined with an identifier of a specific validated right to perform only that check.
RP: ADS_RIGHT_DS_READ_PROP - Read the properties of a DS object.
WP: ADS_RIGHT_DS_WRITE_PROP - Write properties for a DS object.
DT: ADS_RIGHT_DS_DELETE_TREE - Delete a tree of DS objects.
LO: ADS_RIGHT_DS_LIST_OBJECT - List a tree of DS objects.
CR: ADS_RIGHT_DS_CONTROL_ACCESS - Access allowed only after extended rights checks supported by the object are performed. This flag can be used alone to perform all extended rights checks on the object or it can be combined with an identifier of a specific extended right to perform only that check.
RC: READ_CONTROL - The right to read the information in the object's security descriptor, not including the information in the system access control list (SACL). (This is a Standard Access Right, please read more
object_guid - n/a,
inherit_object_guid - n/a,
account_sid - "SY": Local system. The corresponding RID is SECURITY_LOCAL_SYSTEM_RID.

Now what we need to do is to set the appropriate permissions to Start/Stop Windows Services to the groups or users we want. In this case we need the current non-Admin user be able to Start/Stop the service so we are going to set the permissions to that user. To do that, we need the SID of that particular Windows User Account. To obtain it, open up the Registry (Start > regedit) and locate the following registry key.

LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ProfileList

Under that there is a seperate Key for each an every user account in this computer, and the key name is the SID of each account. SID are usually of the format S-1-5-21-2103278432-2794320136-1883075150-1000. Click on each Key, and you will see on the pane to the right a list of values for each Key. Locate "ProfileImagePath", and by it's value you can find the User Name that SID belongs to. For instance, if the user name of the account is SACH, then the value of "ProfileImagePath" will be something like "C:\Users\Sach". So note down the SID of the user account you want to set the permissions to.

Note2: Here a simple C# code sample which can be used to obtain a list of said Keys and it's values.

//LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ProfileList RegistryKey
RegistryKey profileList = Registry.LocalMachine.OpenSubKey(keyName);

//Get a list of SID corresponding to each account on the computer
string[] sidList = profileList.GetSubKeyNames();

foreach (string sid in sidList)
    //Based on above names, get 'Registry Keys' corresponding to each SID
    RegistryKey profile = Registry.LocalMachine.OpenSubKey(Path.Combine(keyName, sid));

    string strSID = sid;
    //UserName which is represented by above SID    
    string strUserName = (string)profile.GetValue("ProfileImagePath");

Now that we have the SID of the user account we want to set the permissions to, let's get down to it. Let's assume the SID of the user account is S-1-5-21-2103278432-2794320136-1883075150-1000. Copy the output of the [sc sdshow ] command to a text editor. It will look like this:


Now, copy the (A;;CCLCSWRPWPDTLOCRRC;;;SY) part of the above text, and paste it just before the S:(AU;... part of the text. Then change that part to look like this: (A;;RPWPCR;;;S-1-5-21-2103278432-2794320136-1883075150-1000)

Then add sc sdset at the front, and enclose the above part with quotes. Your final command should look something like the following:


Now execute this in your command prompt, and it should give the output as follows if successful:

[SC] SetServiceObjectSecurity SUCCESS

Now we're good to go! Your non-Admin user account has been granted permissions to Start/Stop your service! Try loggin in to the user account and Start/Stop the service and it should let you do that.

2. Access through IIS Method

In this case, we need to grant the permission to the IIS user "Network Services" instead of the logon Windows user account. The procedure is the same, only the parameters of the command will be changed. Since we set the permission to "Network Services", replace SID with the string "NS" in the final sdset command we used previously. The final command should look something like this:


Execute it in the command prompt from an Admin user account, and voila! You have the permission to Start / Stop the service from any user account (irrespective of whether it ia an Admin account or not) using a WebMethod. Refer to Note1 to find out how to do so.

Facebook page automatic "like" URL (for QR Code)

This has changed, it's now fb://profile/(profileID)

Node.js Logging

Observe that errorLogger is a wrapper around logger.trace. But the level of logger is ERROR so logger.trace will not log its message to logger's appenders.

The fix is to change logger.trace to logger.error in the body of errorLogger.

FIFO class in Java

Not sure what you call FIFO these days since Queue is FILO, but when I was a student we used the Stack<E> with the simple push, pop, and a peek... It is really that simple, no need for complicating further with Queue and whatever the accepted answer suggests.

What are Java command line options to set to allow JVM to be remotely debugged?

Here is the easiest solution.

There are a lot of environment special configurations needed if you are using Maven. So, if you start your program from maven, just run the mvnDebug command instead of mvn, it will take care of starting your app with remote debugging configurated. Now you can just attach a debugger on port 8000.

It'll take care of all the environment problems for you.

HTML form readonly SELECT tag/input

Rather than the select itself, you could disable all of the options except for the currently selected option. This gives the appearance of a working drop-down, but only the option you want passed in is a valid selection.

"make_sock: could not bind to address [::]:443" when restarting apache (installing trac and mod_wsgi)

I'm adding another answer to this as I had the same problem and solved it the same way: I had installed SSL on apache2 using a2enmod ssl, which seems to have added an extra configuration in /etc/apache2/ports.conf:

NameVirtualHost *:80
Listen 80

NameVirtualHost *:443
Listen 443

<IfModule mod_ssl.c>
    Listen 443

<IfModule mod_gnutls.c>
    Listen 443

I had to comment out the first Listen 443 after the NameVirtualHost *:443 directive:

NameVirtualHost *:443
#Listen 443

But I'm thinking I can as well let it and comment the others. Anyway, thank you for the solution :)

Count indexes using "for" in Python

use enumerate:

>>> l = ['a', 'b', 'c', 'd']
>>> for index, val in enumerate(l):
...    print "%d: %s" % (index, val)
0: a
1: b
2: c
3: d

paint() and repaint() in Java

Difference between Paint() and Repaint() method


This method holds instructions to paint this component. Actually, in Swing, you should change paintComponent() instead of paint(), as paint calls paintBorder(), paintComponent() and paintChildren(). You shouldn't call this method directly, you should call repaint() instead.


This method can't be overridden. It controls the update() -> paint() cycle. You should call this method to get a component to repaint itself. If you have done anything to change the look of the component, but not its size ( like changing color, animating, etc. ) then call this method.

add Shadow on UIView using swift 3

Swift 5 Just call this function and pass your view

public func setViewSettingWithBgShade(view: UIView)
    view.layer.cornerRadius = 8
    view.layer.borderWidth = 1
    view.layer.borderColor = AppTextFieldBorderColor.cgColor

    //MARK:- Shade a view
    view.layer.shadowOpacity = 0.5
    view.layer.shadowOffset = CGSize(width: 1.0, height: 1.0)
    view.layer.shadowRadius = 3.0
    view.layer.shadowColor =
    view.layer.masksToBounds = false

Notify ObservableCollection when Item changes

All the solutions here are correct,but they are missing an important scenario in which the method Clear() is used, which doesn't provide OldItems in the NotifyCollectionChangedEventArgs object.

this is the perfect ObservableCollection .

public delegate void ListedItemPropertyChangedEventHandler(IList SourceList, object Item, PropertyChangedEventArgs e);
public class ObservableCollectionEX<T> : ObservableCollection<T>
    #region Constructors
    public ObservableCollectionEX() : base()
        CollectionChanged += ObservableCollection_CollectionChanged;
    public ObservableCollectionEX(IEnumerable<T> c) : base(c)
        CollectionChanged += ObservableCollection_CollectionChanged;
    public ObservableCollectionEX(List<T> l) : base(l)
        CollectionChanged += ObservableCollection_CollectionChanged;


    public new void Clear()
        foreach (var item in this)            
            if (item is INotifyPropertyChanged i)                
                i.PropertyChanged -= Element_PropertyChanged;            
    private void ObservableCollection_CollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
        if (e.OldItems != null)
            foreach (var item in e.OldItems)                
                if (item != null && item is INotifyPropertyChanged i)                    
                    i.PropertyChanged -= Element_PropertyChanged;

        if (e.NewItems != null)
            foreach (var item in e.NewItems)                
                if (item != null && item is INotifyPropertyChanged i)
                    i.PropertyChanged -= Element_PropertyChanged;
                    i.PropertyChanged += Element_PropertyChanged;
    private void Element_PropertyChanged(object sender, PropertyChangedEventArgs e) => ItemPropertyChanged?.Invoke(this, sender, e);

    public ListedItemPropertyChangedEventHandler ItemPropertyChanged;


What is <=> (the 'Spaceship' Operator) in PHP 7?

The <=> ("Spaceship") operator will offer combined comparison in that it will :

Return 0 if values on either side are equal
Return 1 if the value on the left is greater
Return -1 if the value on the right is greater

The rules used by the combined comparison operator are the same as the currently used comparison operators by PHP viz. <, <=, ==, >= and >. Those who are from Perl or Ruby programming background may already be familiar with this new operator proposed for PHP7.

   //Comparing Integers

    echo 1 <=> 1; //output  0
    echo 3 <=> 4; //output -1
    echo 4 <=> 3; //output  1

    //String Comparison

    echo "x" <=> "x"; //output  0
    echo "x" <=> "y"; //output -1
    echo "y" <=> "x"; //output  1

Reset C int array to zero : the fastest way?

Here's the function I use:

template<typename T>
static void setValue(T arr[], size_t length, const T& val)
    std::fill(arr, arr + length, val);

template<typename T, size_t N>
static void setValue(T (&arr)[N], const T& val)
    std::fill(arr, arr + N, val);

You can call it like this:

//fixed arrays
int a[10];
setValue(a, 0);

//dynamic arrays
int *d = new int[length];
setValue(d, length, 0);

Above is more C++11 way than using memset. Also you get compile time error if you use dynamic array with specifying the size.

$(document).ready equivalent without jQuery

Most minimal and 100% working

I have picked the answer from PlainJS and it's working fine for me. It extends DOMContentLoaded so that it can be accepted at all the browsers.

This function is the equivalent of jQuery's $(document).ready() method:

document.addEventListener('DOMContentLoaded', function(){
    // do something

However, in contrast to jQuery, this code will only run properly in modern browsers (IE > 8) and it won't in case the document is already rendered at the time this script gets inserted (e.g. via Ajax). Therefore, we need to extend this a little bit:

function run() {
    // do something

// in case the document is already rendered
if (document.readyState!='loading') run();
// modern browsers
else if (document.addEventListener) 
document.addEventListener('DOMContentLoaded', run);
// IE <= 8
else document.attachEvent('onreadystatechange', function(){
    if (document.readyState=='complete') run();

This covers basically all possibilities and is a viable replacement for the jQuery helper.

100% width in React Native Flexbox

Here you go:

Just change the line1 style as per below:

line1: {
    backgroundColor: '#FDD7E4',

How to get disk capacity and free space of remote computer

I created a PowerShell advanced function (script cmdlet) a while back that allows you to query multiple computers.

The code for the function is a little over 100 lines long, so you can find it here: PowerShell version of the df command

Check out the Usage section for examples. The following usage example queries a set of remote computers (input from the PowerShell pipeline) and displays the output in a table format with numeric values in human-readable form:

PS> $cred = Get-Credential -Credential 'example\administrator'
PS> 'db01','dc01','sp01' | Get-DiskFree -Credential $cred -Format | Format-Table -GroupBy Name -AutoSize

   Name: DB01

Name Vol Size  Used  Avail Use% FS   Type
---- --- ----  ----  ----- ---- --   ----
DB01 C:  39.9G 15.6G 24.3G   39 NTFS Local Fixed Disk
DB01 D:  4.1G  4.1G  0B     100 CDFS CD-ROM Disc

   Name: DC01

Name Vol Size  Used  Avail Use% FS   Type
---- --- ----  ----  ----- ---- --   ----
DC01 C:  39.9G 16.9G 23G     42 NTFS Local Fixed Disk
DC01 D:  3.3G  3.3G  0B     100 CDFS CD-ROM Disc
DC01 Z:  59.7G 16.3G 43.4G   27 NTFS Network Connection

   Name: SP01

Name Vol Size   Used   Avail Use% FS   Type
---- --- ----   ----   ----- ---- --   ----
SP01 C:  39.9G  20G    19.9G   50 NTFS Local Fixed Disk
SP01 D:  722.8M 722.8M 0B     100 UDF  CD-ROM Disc

Convert a String representation of a Dictionary to a dictionary?

Use json. the ast library consumes a lot of memory and and slower. I have a process that needs to read a text file of 156Mb. Ast with 5 minutes delay for the conversion dictionary json and 1 minutes using 60% less memory!

Getting the closest string match

A very, very good resource for these kinds of algorithms is Simmetrics:

Unfortunately the awesome website containing a lot of the documentation is gone :( In case it comes back up again, its previous address was this:

Voila (courtesy of "Wayback Machine"):

You can study the code source, there are dozens of algorithms for these kinds of comparisons, each with a different trade-off. The implementations are in Java.

When is null or undefined used in JavaScript?

I might be missing something, but afaik, you get undefined only

Update: Ok, I missed a lot, trying to complete:

You get undefined...

... when you try to access properties of an object that don't exist:

var a = {} // undefined

... when you have declared a variable but not initialized it:

var a;
// a is undefined

... when you access a parameter for which no value was passed:

function foo (a, b) {
    // something

foo(42); // b inside foo is undefined

... when a function does not return a value:

function foo() {};
var a = foo(); // a is undefined

It might be that some built-in functions return null on some error, but if so, then it is documented. null is a concrete value in JavaScript, undefined is not.

Normally you don't need to distinguish between those. Depending on the possible values of a variable, it is sufficient to use if(variable) to test whether a value is set or not (both, null and undefined evaluate to false).

Also different browsers seem to be returning these differently.

Please give a concrete example.

Php - Your PHP installation appears to be missing the MySQL extension which is required by WordPress

When I upgraded my website PHP from version 5.6 to 7.2, I encountered this problem “Your PHP installation appears to be missing the MySQL extension which is required by WordPress”. It turns out that mysql extension is no longer supported in PHP version 7.2. It is now using mysqli extention. I am using old version of WordPress which still using mysql extension that is why the problem existed. So what I did is upgraded the WordPress to the core. This solve the problem.

Here's the steps I followed when upgrading WordPress manually.

  1. First I created a full backup of my website. This is very important in case of mistake.
  2. I download the newest WordPress ZIP file from
  3. I unzipped the file into a local directory of my computer.
  4. I went to my website root directory and deleted your ‘wp-includes’ and ‘wp-admin’ directories. I used sFTP connection using Filezilla software.
  5. I uploaded the new wp-includes and wp-admin directories from the new version of WordPress I unzipped to my website root directory and replaced the directories I just deleted.
  6. I did not delete the wp-content directory or any of the files in that directory. I just copied over the files from the wp-content directory in the new version of WordPress to my existing wp-content directory. All existing files with the same name have been overwritten.
  7. I copied all files from the root (‘/’) directory of the new version of WordPress that I unzipped into my website root directory (or the root directory of your WordPress installation). Existing files has been overwritten and new files has been copied across. wp-config.php file was not be affected because WordPress has never distributed with a wp-config.php file.
  8. I compare wp-config-sample.php which was distributed with WordPress but did not find anything to change so I just used the old one.
  9. I cleared my browser cache to ensure I can see all changes.
  10. I checked the site and there is no error now. The upgrade was completed.

How to Select Every Row Where Column Value is NOT Distinct

select CustomerName,count(1) from Customers group by CustomerName having count(1) > 1

Slicing of a NumPy 2d array, or how do I extract an mxm submatrix from an nxn array (n>m)?

I'm not sure how efficient this is but you can use range() to slice in both axis

 x[range(1,3), :][:,range(1,3)] 

CSS fixed width in a span

<style type="text/css">

span {
  width: 50px;


You can do this method for assigning width for inline elements

Django ChoiceField

Better Way to Provide Choice inside a django Model :

from django.db import models

class Student(models.Model):
    JUNIOR = 'JR'
    SENIOR = 'SR'
        (FRESHMAN, 'Freshman'),
        (SOPHOMORE, 'Sophomore'),
        (JUNIOR, 'Junior'),
        (SENIOR, 'Senior'),
        (GRADUATE, 'Graduate'),
    year_in_school = models.CharField(

How do I select text nodes with jQuery?

$('body').find('*').contents().filter(function () { return this.nodeType === 3; });

How to drop all tables from a database with one SQL query?

You could also use the following script to drop everything, including the following:

  • non-system stored procedures
  • views
  • functions
  • foreign key constraints
  • primary key constraints
  • tables

/* Drop all non-system stored procs */

SELECT @name = (SELECT TOP 1 [name] FROM sysobjects WHERE [type] = 'P' AND category = 0 ORDER BY [name])

WHILE @name is not null
    SELECT @SQL = 'DROP PROCEDURE [dbo].[' + RTRIM(@name) +']'
    EXEC (@SQL)
    PRINT 'Dropped Procedure: ' + @name
    SELECT @name = (SELECT TOP 1 [name] FROM sysobjects WHERE [type] = 'P' AND category = 0 AND [name] > @name ORDER BY [name])

/* Drop all views */

SELECT @name = (SELECT TOP 1 [name] FROM sysobjects WHERE [type] = 'V' AND category = 0 ORDER BY [name])

    SELECT @SQL = 'DROP VIEW [dbo].[' + RTRIM(@name) +']'
    EXEC (@SQL)
    PRINT 'Dropped View: ' + @name
    SELECT @name = (SELECT TOP 1 [name] FROM sysobjects WHERE [type] = 'V' AND category = 0 AND [name] > @name ORDER BY [name])

/* Drop all functions */

SELECT @name = (SELECT TOP 1 [name] FROM sysobjects WHERE [type] IN (N'FN', N'IF', N'TF', N'FS', N'FT') AND category = 0 ORDER BY [name])

    SELECT @SQL = 'DROP FUNCTION [dbo].[' + RTRIM(@name) +']'
    EXEC (@SQL)
    PRINT 'Dropped Function: ' + @name
    SELECT @name = (SELECT TOP 1 [name] FROM sysobjects WHERE [type] IN (N'FN', N'IF', N'TF', N'FS', N'FT') AND category = 0 AND [name] > @name ORDER BY [name])

/* Drop all Foreign Key constraints */
DECLARE @constraint VARCHAR(254)


WHILE @name is not null
    WHILE @constraint IS NOT NULL
        SELECT @SQL = 'ALTER TABLE [dbo].[' + RTRIM(@name) +'] DROP CONSTRAINT [' + RTRIM(@constraint) +']'
        EXEC (@SQL)
        PRINT 'Dropped FK Constraint: ' + @constraint + ' on ' + @name

/* Drop all Primary Key constraints */
DECLARE @constraint VARCHAR(254)


    WHILE @constraint is not null
        SELECT @SQL = 'ALTER TABLE [dbo].[' + RTRIM(@name) +'] DROP CONSTRAINT [' + RTRIM(@constraint)+']'
        EXEC (@SQL)
        PRINT 'Dropped PK Constraint: ' + @constraint + ' on ' + @name

/* Drop all tables */

SELECT @name = (SELECT TOP 1 [name] FROM sysobjects WHERE [type] = 'U' AND category = 0 ORDER BY [name])

    SELECT @SQL = 'DROP TABLE [dbo].[' + RTRIM(@name) +']'
    EXEC (@SQL)
    PRINT 'Dropped Table: ' + @name
    SELECT @name = (SELECT TOP 1 [name] FROM sysobjects WHERE [type] = 'U' AND category = 0 AND [name] > @name ORDER BY [name])

How to clone ArrayList and also clone its contents?

I, personally, would add a constructor to Dog:

class Dog
    public Dog()
    { ... } // Regular constructor

    public Dog(Dog dog) {
        // Copy all the fields of Dog.

Then just iterate (as shown in Varkhan's answer):

public static List<Dog> cloneList(List<Dog> dogList) {
    List<Dog> clonedList = new ArrayList<Dog>(dogList.size());
    for (Dog dog : dogList) {
        clonedList.add(new Dog(dog));
    return clonedList;

I find the advantage of this is you don't need to screw around with the broken Cloneable stuff in Java. It also matches the way that you copy Java collections.

Another option could be to write your own ICloneable interface and use that. That way you could write a generic method for cloning.

DataTables: Uncaught TypeError: Cannot read property 'defaults' of undefined

I got the same error, I'm using laravel 5.4 with webpack, here package.json before:

  "devDependencies": {
    "jquery": "^1.12.4",
  "dependencies": {
    "": "^2.1.1",

I had to move jquery and npm packages under one of these "dependencies": {} or "devDependencies": {} in package.json and the error disappeared, after:

  "devDependencies": {
    "jquery": "^1.12.4",
    "": "^2.1.1",

I hope that helps!

How to call shell commands from Ruby

Here's the best article in my opinion about running shell scripts in Ruby: "6 Ways to Run Shell Commands in Ruby".

If you only need to get the output use backticks.

I needed more advanced stuff like STDOUT and STDERR so I used the Open4 gem. You have all the methods explained there.

How do I make bootstrap table rows clickable?

That code transforms any bootstrap table row that has data-href attribute set into a clickable element

Note: data-href attribute is a valid tr attribute (HTML5), href attributes on tr element are not.

    $('.table tr[data-href]').each(function(){
            }).click( function(){ 
                document.location = $(this).attr('data-href'); 

In Matplotlib, what does the argument mean in fig.add_subplot(111)?

enter image description here

import matplotlib.pyplot as plt

The first code creates the first subplot in a layout that has 3 rows and 2 columns.

The three graphs in the first column denote the 3 rows. The second plot comes just below the first plot in the same column and so on.

The last two plots have arguments (2, 2) denoting that the second column has only two rows, the position parameters move row wise.

Static Initialization Blocks

If your static variables need to be set at runtime then a static {...} block is very helpful.

For example, if you need to set the static member to a value which is stored in a config file or database.

Also useful when you want to add values to a static Map member as you can't add these values in the initial member declaration.

Visual Studio Community 2015 expiration date

Here is an instructions for the problem:

You can evaluate Visual Studio for free up to 30 days.

To Unlock Visual Studio using an online subscription

Link Microsoft account to Visual Studio 2015

I have encountered this problem: enter image description here

Possible solution can be found at the link above.

This message indicates that while your subscription may still be valid, the license token Visual Studio uses to keep your subscription up to date hasn’t been refreshed and has gone stale due to one of the following reasons: You have not used Visual Studio or have had no internet connection for an extend period of time. You signed out of Visual Studio.

Is there a way to make a PowerShell script work by double clicking a .ps1 file?

This worked for me on Windows 10 and powershell 5.1:

  • right click on the .ps1 file
  • Open with...
  • Choose another app
  • Copy the location of powershell.exe to the address bar (by default it won't show windows folder) i.e. C:\Windows\System32\WindowsPowerShell\v1.0
  • select powershell.exe
  • select "Always use this app to open .ps1 files"
  • click OK

ReactJS SyntheticEvent stopPropagation() only works with React events?

I was able to resolve this by adding the following to my component:

componentDidMount() {
  ReactDOM.findDOMNode(this).addEventListener('click', (event) => {
  }, false);

LaTeX package for syntax highlighting of code in various languages

After asking a similar question I’ve created another package which uses Pygments, and offers quite a few more options than texments. It’s called minted and is quite stable and usable.

Just to show it off, here’s a code highlighted with minted:

Example code

Python 'If not' syntax

Yes, if bar is not None is more explicit, and thus better, assuming it is indeed what you want. That's not always the case, there are subtle differences: if not bar: will execute if bar is any kind of zero or empty container, or False. Many people do use not bar where they really do mean bar is not None.

How to vertically align a html radio button to it's label?

Something like this should work


input {
    float: left;
    clear: left;
    width: 50px;
    line-height: 20px;

label {
    float: left;
    vertical-align: middle;


When the propagation setting is PROPAGATION_REQUIRED, a logical transaction scope is created for each method upon which the setting is applied. Each such logical transaction scope can determine rollback-only status individually, with an outer transaction scope being logically independent from the inner transaction scope. Of course, in case of standard PROPAGATION_REQUIRED behavior, all these scopes will be mapped to the same physical transaction. So a rollback-only marker set in the inner transaction scope does affect the outer transaction's chance to actually commit (as you would expect it to).

enter image description here

Using Jquery AJAX function with datatype HTML

Here is a version that uses dataType html, but this is far less explicit, because i am returning an empty string to indicate an error.

Ajax call:

  type : 'POST',
  url : 'post.php',
  dataType : 'html',
  data: {
      email : $('#email').val()
  success : function(data){
      $('#message').removeClass().addClass((data == '') ? 'error' : 'success')
      if (data == '') {
          $('#message').html("Format your email correcly");
  error : function(XMLHttpRequest, textStatus, errorThrown) {
      .text('There was an error.').show(500);




function processEmail($email) {
    if (preg_match("#^[a-zA-Z0-9_.-]+@[a-zA-Z0-9-]+.[a-zA-Z0-9-.]+$#", $email)) {
        // your logic here (ex: add into database)
        return true;
    return false;

if (processEmail($_POST['email'])) {
    echo "<span>Your email is <strong>{$_POST['email']}</strong></span>";

Comparing arrays in C#

"Why do i get that error?" - probably, you don't have "using System.Collections;" at the top of the file - only "using System.Collections.Generic;" - however, generics are probably safer - see below:

static bool ArraysEqual<T>(T[] a1, T[] a2)
    if (ReferenceEquals(a1,a2))
        return true;

    if (a1 == null || a2 == null)
        return false;

    if (a1.Length != a2.Length)
        return false;

    EqualityComparer<T> comparer = EqualityComparer<T>.Default;
    for (int i = 0; i < a1.Length; i++)
        if (!comparer.Equals(a1[i], a2[i])) return false;
    return true;

What is the difference between `new Object()` and object literal notation?

2019 Update

I ran the same code as @rjloura on my OSX High Sierra 10.13.6 node version 10.13.0 and these are the results

console.log('Testing Array:');
for(var i=0; i<200000000; i++){var arr = []};

console.time('using new');
for(var i=0; i<200000000; i++){var arr = new Array};
console.timeEnd('using new');

console.log('Testing Object:');

for(var i=0; i<200000000; i++){var obj = {}};

console.time('using new');
for(var i=0; i<200000000; i++){var obj = new Object};
console.timeEnd('using new');

Testing Array:
using[]: 117.613ms
using new: 117.168ms
Testing Object:
using{}: 117.205ms
using new: 118.644ms

Staging Deleted files

Ian Mackinnon found the answer, but it's better with xargs:

git ls-files --deleted -z | xargs -r0 git rm

As a git alias:

git config --global alias.rm-deleted '!git ls-files --deleted -z | xargs -r0 git rm'

This uses xargs with NUL termination (the only byte guarranteed not to appear in a path) and the option to not run git rm if the file list is empty.

This syntax is also fish compatible.

Python in Xcode 4+?

I've created Xcode 4 templates to simplify the steps provided by Tyler.
The result is Python Project Template for Xcode 4.

Now what you need to do is download the templates, move it to /Developer/Library/Xcode/Templates/Project Templates/Mac/Others/ and then new a Python project with Xcode 4.

It still needs manual Scheme setup (you can refer to steps 12–20 provided by Tyler.)

How to restart ADB manually from Android Studio

When I had this problem, I wrote adb kill-server and adb restart-server in terminal, but the problem appeared again the next day. Then I updated GPU debugging tools in the Android SDK manager and restarted the computer, which worked for me.

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

I tried neemzy's approach, but it didn't work for me using 1.2.0-rc.3. The script tag would be inserted into the DOM, but the javascript path would not be loaded. I suspect it was because the javascript i was trying to load was from a different domain/protocol. So I took a different approach, and this is what I came up with, using google maps as an example: (Gist)

angular.module('testApp', []).
    directive('lazyLoad', ['$window', '$q', function ($window, $q) {
        function load_script() {
            var s = document.createElement('script'); // use global document since Angular's $document is weak
            s.src = '';
        function lazyLoadApi(key) {
            var deferred = $q.defer();
            $window.initialize = function () {
            // thanks to Emil Stenström:
            if ($window.attachEvent) {  
                $window.attachEvent('onload', load_script); 
            } else {
                $window.addEventListener('load', load_script, false);
            return deferred.promise;
        return {
            restrict: 'E',
            link: function (scope, element, attrs) { // function content is optional
            // in this example, it shows how and when the promises are resolved
                if ($ && $ {
                    console.log('gmaps already loaded');
                } else {
                    lazyLoadApi().then(function () {
                        console.log('promise resolved');
                        if ($ && $ {
                            console.log('gmaps loaded');
                        } else {
                            console.log('gmaps not loaded');
                    }, function () {
                        console.log('promise rejected');

I hope it's helpful for someone.

Marquee text in Android

I have tried all of the above, but for me its didn't work. When I add


then it's worked perfectly for me. I don't know why. But I am happy to work it.

Here is my full answer.



What is the difference between “int” and “uint” / “long” and “ulong”?

uint and ulong are the unsigned versions of int and long. That means they can't be negative. Instead they have a larger maximum value.

Type    Min                           Max                           CLS-compliant
int     -2,147,483,648                2,147,483,647                 Yes
uint    0                             4,294,967,295                 No
long    –9,223,372,036,854,775,808    9,223,372,036,854,775,807     Yes
ulong   0                             18,446,744,073,709,551,615    No

To write a literal unsigned int in your source code you can use the suffix u or U for example 123U.

You should not use uint and ulong in your public interface if you wish to be CLS-Compliant.

Read the documentation for more information:

By the way, there is also short and ushort and byte and sbyte.

How do I download code using SVN/Tortoise from Google Code?

Select Tortoise SVN - > Settings - > NetWork

Fill the required proxy if any and then check.

An invalid XML character (Unicode: 0xc) was found

For people who are reading byte array into String and trying to convert to object with JAXB, you can add "iso-8859-1" encoding by creating String from byte array like this:

String JAXBallowedString= new String(byte[] input, "iso-8859-1");

This would replace the conflicting byte to single-byte encoding which JAXB can handle. Obviously this solution is only to parse the xml.

Keras, How to get the output of each layer?


One simple way is to create a new Model that will output the layers that you are interested in:

from keras.models import Model

model = ...  # include here your original model

layer_name = 'my_layer'
intermediate_layer_model = Model(inputs=model.input,
intermediate_output = intermediate_layer_model.predict(data)

Alternatively, you can build a Keras function that will return the output of a certain layer given a certain input, for example:

from keras import backend as K

# with a Sequential model
get_3rd_layer_output = K.function([model.layers[0].input],
layer_output = get_3rd_layer_output([x])[0]

Detecting the onload event of a window opened with

First of all, when your first initial window is loaded, it is cached. Therefore, when creating a new window from the first window, the contents of the new window are not loaded from the server, but are loaded from the cache. Consequently, no onload event occurs when you create the new window.

However, in this case, an onpageshow event occurs. It always occurs after the onload event and even when the page is loaded from cache. Plus, it now supported by all major browsers.

 window.popup =$(this).attr('href'), 'Ad', 'left=20,top=20,width=500,height=500,toolbar=1,resizable=0');
 $(window.popup).onpageshow = function() {
     alert("Popup has loaded a page");

The w3school website elaborates more on this:

The onpageshow event is similar to the onload event, except that it occurs after the onload event when the page first loads. Also, the onpageshow event occurs every time the page is loaded, whereas the onload event does not occur when the page is loaded from the cache.

Randomize a List<T>

    public static List<T> Randomize<T>(List<T> list)
        List<T> randomizedList = new List<T>();
        Random rnd = new Random();
        while (list.Count > 0)
            int index = rnd.Next(0, list.Count); //pick a random item from the master list
            randomizedList.Add(list[index]); //place it at the end of the randomized list
        return randomizedList;

Javascript Date: next month

Instead, try:

var now = new Date();
current = new Date(now.getFullYear(), now.getMonth()+1, 1);

jQuery location href

You can use just JavaScript:

window.location = '';

Change the project theme in Android Studio?

In Manifest theme sets with style name (AppTheme and myDialog)/ You can set new styles in styles.xml

            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />

styles.xml example


<!-- Base application theme. -->
<style name="AppTheme" parent="android:Theme.Black">
    <!-- Customize your theme here. -->

<style name="myDialog" parent="android:Theme.Dialog">


In parent you set actualy the theme

Eclipse error, "The selection cannot be launched, and there are no recent launches"

Eclipse can't work out what you want to run and since you've not run anything before, it can't try re-running that either.

Instead of clicking the green 'run' button, click the dropdown next to it and chose Run Configurations. On the Android tab, make sure it's set to your project. In the Target tab, set the tick box and options as appropriate to target your device. Then click Run. Keep an eye on your Console tab in Eclipse - that'll let you know what's going on. Once you've got your run configuration set, you can just hit the green 'run' button next time.

Sometimes getting everything to talk to your device can be problematic to begin with. Consider using an AVD (i.e. an emulator) as alternative, at least to begin with if you have problems. You can easily create one from the menu Window -> Android Virtual Device Manager within Eclipse.

To view the progress of your project being installed and started on your device, check the console. It's a panel within Eclipse with the tabs Problems/Javadoc/Declaration/Console/LogCat etc. It may be minimised - check the tray in the bottom right. Or just use Window/Show View/Console from the menu to make it come to the front. There are two consoles, Android and DDMS - there is a dropdown by its icon where you can switch.

How can I create a dynamic button click event on a dynamic button?

Simply add the eventhandler to the button when creating it.

 button.Click += new EventHandler(this.button_Click);

void button_Click(object sender, System.EventArgs e)
//your stuff...

How to close current tab in a browser window?

As far as I can tell, it no longer is possible in Chrome or FireFox. It may still be possible in IE (at least pre-Edge).

When do you use map vs flatMap in RxJava?

In that scenario use map, you don't need a new Observable for it.

you should use Exceptions.propagate, which is a wrapper so you can send those checked exceptions to the rx mechanism

Observable<String> obs = Observable.from(jsonFile).map(new Func1<File, String>() { 
    @Override public String call(File file) {
        try { 
            return new Gson().toJson(new FileReader(file), Object.class);
        } catch (FileNotFoundException e) {
            throw Exceptions.propagate(t); /will propagate it as error

You then should handle this error in the subscriber

obs.subscribe(new Subscriber<String>() {
    public void onNext(String s) { //valid result }

    public void onCompleted() { } 

    public void onError(Throwable e) { //e might be the FileNotFoundException you got }

There is an excellent post for it:

How to check the first character in a string in Bash or UNIX shell?

$ foo="/some/directory/file"
$ [ ${foo:0:1} == "/" ] && echo 1 || echo 0
$ foo="[email protected]:/some/directory/file"
$ [ ${foo:0:1} == "/" ] && echo 1 || echo 0

Cut Corners using CSS

You can use clip-path, as Stewartside and Sviatoslav Oleksiv mentioned. To make things easy, I created a sass mixin:

@mixin cut-corners ($left-top, $right-top: 0px, $right-bottom: 0px, $left-bottom: 0px) {
  clip-path: polygon($left-top 0%, calc(100% - #{$right-top}) 0%, 100% $right-top, 100% calc(100% - #{$right-bottom}), calc(100% - #{$right-bottom}) 100%, $left-bottom 100%, 0% calc(100% - #{$left-bottom}), 0% $left-top);

.cut-corners {
  @include cut-corners(10px, 0, 25px, 50px);

How do you perform wireless debugging in Xcode 9 with iOS 11, Apple TV 4K, etc?

I just talked to some Xcode engineers at WWDC and the auto discovery of iDevices is still a little buggy. Also sometimes your phone is not correctly broadcasting. Switching your device on and off can help.

There are a few workarounds/fallbacks:

You can check if your phone is broadcasting with Bonjour Browser ( Look if your wifi address is listed under the service called '_apple-mobdev2._tcp. - 215' (you can find your wifi address here: settings > general > about > wifi address.

As a fallback you can connect to your device by manually entering the IP address (right click on your devices in the Devices window). However this IP address will be persisted, so if you change networks you'll need to reset this. That option is not available in Xcode yet, but you can do it via the terminal with the following command:

defaults read | grep IDEIDS

This will print an identifier which you need to use in the next command:

defaults delete <identifier>

Now the ip address is cleared and you can enter a new one.

The last option is to create a computer-to-computer network. This works fine, but logically you won't have internet access then.

javascript windows alert with redirect function

You could do this:

echo "<script>alert('Successfully Updated'); window.location = './edit.php';</script>";

How to downgrade the installed version of 'pip' on windows?

well the only thing that will work is

python -m pip install pip==

you can and should run it under IDE terminal (mine was pycharm)

How to declare and initialize a static const array as a class member?

// in foo.h
class Foo {
    static const unsigned char* Msg;

// in foo.cpp
static const unsigned char Foo_Msg_data[] = {0x00,0x01};
const unsigned char* Foo::Msg = Foo_Msg_data;

What is System, out, println in System.out.println() in Java

System is a final class from the java.lang package.

out is a class variable of type PrintStream declared in the System class.

println is a method of the PrintStream class.

Wrapping text inside input type="text" element HTML/CSS

That is the textarea's job - for multiline text input. The input won't do it; it wasn't designed to do it.

So use a textarea. Besides their visual differences, they are accessed via JavaScript the same way (use value property).

You can prevent newlines being entered via the input event and simply using a replace(/\n/g, '').

PHP If Statement with Multiple Conditions

An elegant way is building an array on the fly and using in_array():

if (in_array($var, array("abc", "def", "ghi")))

The switch statement is also an alternative:

switch ($var) {
case "abc":
case "def":
case "hij":
    echo "yes";
    echo "no";

vector vs. list in STL

List is Doubly Linked List so it is easy to insert and delete an element. We have to just change the few pointers, whereas in vector if we want to insert an element in the middle then each element after it has to shift by one index. Also if the size of the vector is full then it has to first increase its size. So it is an expensive operation. So wherever insertion and deletion operations are required to be performed more often in such a case list should be used.

Problems with a PHP shell script: "Could not open input file"

For me the problem was I had to use /usr/bin/php-cgi command instead of just /usr/bin/php

php-cgi is the command run when accessed thru web browser.

php is the CLI command line command.

Not sure why php cli is not working, but running with php-cgi instead fixed the problem for me.

Using Get-childitem to get a list of files modified in the last 3 days

Try this:

(Get-ChildItem -Path c:\pstbak\*.* -Filter *.pst | ? {
  $_.LastWriteTime -gt (Get-Date).AddDays(-3) 

Creating an Arraylist of Objects

How to Creating an Arraylist of Objects.

Create an array to store the objects:

ArrayList<MyObject> list = new ArrayList<MyObject>();

In a single step:

list.add(new MyObject (1, 2, 3)); //Create a new object and adding it to list. 


MyObject myObject = new MyObject (1, 2, 3); //Create a new object.
list.add(myObject); // Adding it to the list.

MySQL Nested Select Query?

You just need to write the first query as a subquery (derived table), inside parentheses, pick an alias for it (t below) and alias the columns as well.

The DISTINCT can also be safely removed as the internal GROUP BY makes it redundant:

SELECT DATE(`date`) AS `date` , COUNT(`player_name`) AS `player_count`
    SELECT MIN(`date`) AS `date`, `player_name`
    FROM `player_playtime`
    GROUP BY `player_name`
) AS t

Since the COUNT is now obvious that is only counting rows of the derived table, you can replace it with COUNT(*) and further simplify the query:

SELECT , COUNT(*) AS player_count
    SELECT DATE(MIN(`date`)) AS date
    FROM player_playtime
    GROUP BY player_name
) AS t

SQL Query Where Date = Today Minus 7 Days

Using dateadd to remove a week from the current date.


insert data into database using servlet and jsp in eclipse

String user = request.getParameter("uname");
String pass = request.getParameter("pass");
Class.forName( "com.mysql.jdbc.Driver" );
Connection conn = DriverManager.getConnection( "jdbc:mysql://localhost:3306/rental","root","root" ) ;
Statement st = conn.createStatement();
String sql = "insert into login (user,pass) values('" + user + "','" + pass + "')";

MySQL - How to select data by string length

select * from table order by length(column);

Documentation on the length() function, as well as all the other string functions, is available here.

How to insert a row between two rows in an existing excel with HSSF (Apache POI)

I merged some of the other answers and comments in the following implementation, tested with Apache POI v3.9.

I have only one rownum parameter because I shift down the target row and copy it in the new empty row. Formulas are handled as expected, they are not copied verbatim, with one exception: references to cells that are above the copied line are not updated; the workaround is to replace these explicit references (if any) with references calculated using INDIRECT() as suggested by this post.

protected void copyRow(Sheet worksheet, int rowNum) {
    Row sourceRow = worksheet.getRow(rowNum);

    //Save the text of any formula before they are altered by row shifting
    String[] formulasArray = new String[sourceRow.getLastCellNum()];
    for (int i = 0; i < sourceRow.getLastCellNum(); i++) {
        if (sourceRow.getCell(i) != null && sourceRow.getCell(i).getCellType() == Cell.CELL_TYPE_FORMULA) 
            formulasArray[i] = sourceRow.getCell(i).getCellFormula();

    worksheet.shiftRows(rowNum, worksheet.getLastRowNum(), 1);
    Row newRow = sourceRow;  //Now sourceRow is the empty line, so let's rename it
    sourceRow = worksheet.getRow(rowNum + 1);  //Now the source row is at rowNum+1

    // Loop through source columns to add to new row
    for (int i = 0; i < sourceRow.getLastCellNum(); i++) {
        // Grab a copy of the old/new cell
        Cell oldCell = sourceRow.getCell(i);
        Cell newCell;

        // If the old cell is null jump to next cell
        if (oldCell == null) {
        } else {
            newCell = newRow.createCell(i);

        // Copy style from old cell and apply to new cell
        CellStyle newCellStyle = worksheet.getWorkbook().createCellStyle();

        // If there is a cell comment, copy
        if (oldCell.getCellComment() != null) {

        // If there is a cell hyperlink, copy
        if (oldCell.getHyperlink() != null) {

        // Set the cell data type

        // Set the cell data value
        switch (oldCell.getCellType()) {
            case Cell.CELL_TYPE_BLANK:
            case Cell.CELL_TYPE_BOOLEAN:
            case Cell.CELL_TYPE_ERROR:
            case Cell.CELL_TYPE_FORMULA:
            case Cell.CELL_TYPE_NUMERIC:
            case Cell.CELL_TYPE_STRING:

    // If there are any merged regions in the source row, copy to new row
    for (int i = 0; i < worksheet.getNumMergedRegions(); i++) {
        CellRangeAddress cellRangeAddress = worksheet.getMergedRegion(i);
        if (cellRangeAddress.getFirstRow() == sourceRow.getRowNum()) {
            CellRangeAddress newCellRangeAddress = new CellRangeAddress(newRow.getRowNum(),
                    (newRow.getRowNum() +
                            (cellRangeAddress.getLastRow() - cellRangeAddress.getFirstRow()

I'm using this implementation in production code.

How do I set headers using python's urllib?

adding HTTP headers using urllib2:

from the docs:

import urllib2
req = urllib2.Request('')
req.add_header('Referer', '')
resp = urllib2.urlopen(req)
content =

Insert into a MySQL table or update if exists

In case, you want to keep old field (For ex: name). The query will be:

INSERT INTO table (id, name, age) VALUES(1, "A", 19) ON DUPLICATE KEY UPDATE    
name=name, age=19;

Why do I need to explicitly push a new branch?

You don't, see below

I find this 'feature' rather annoying since I'm not trying to launch rockets to the moon, just push my damn branch. You probably do too or else you wouldn't be here!

Here is the fix: if you want it to implicitly push for the current branch regardless of if that branch exists on origin just issue this command once and you will never have to again anywhere:

git config --global push.default current

So if you make branches like this:

git checkout -b my-new-branch

and then make some commits and then do a

git push -u

to get them out to origin (being on that branch) and it will create said branch for you if it doesn't exist.

Note the -u bit makes sure they are linked if you were to pull later on from said branch. If you have no plans to pull the branch later (or are okay with another one liner if you do) -u is not necessary.

What is the meaning of ImagePullBackOff status on a Kubernetes pod?

You can specify also imagePullPolicy: Never in the container's spec:

- name: nginx
  imagePullPolicy: Never
  image: custom-nginx
  - containerPort: 80

How to get table cells evenly spaced?

If you want all your columns a fixed size, you could use CSS:

    width: 100px;

Or better, use th.TableHeader (I didn't notice that the first time around).

'cannot find or open the pdb file' Visual Studio C++ 2013

There are no problems here this is perfectly normal - it shows informational messages about what debug-info was loaded (and which wasn't) and also that your program executed and exited normally - a zero return code means success.

If you don't see anything on the screen thry running your program with CTRL-F5 instead of just F5.

LoDash: Get an array of values from an array of object properties

const users = [{
      id: 12,
      name: 'Adam'
      id: 14,
      name: 'Bob'
      id: 16,
      name: 'Charlie'
      id: 18,
      name: 'David'
const userIds = _.values(users);
console.log(userIds); //[12, 14, 16, 18]

Using Server.MapPath() inside a static field in ASP.NET MVC

Try HostingEnvironment.MapPath, which is static.

See this SO question for confirmation that HostingEnvironment.MapPath returns the same value as Server.MapPath: What is the difference between Server.MapPath and HostingEnvironment.MapPath?

.substring error: "is not a function"

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

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

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

BackgroundWorker vs background Thread

I knew how to use threads before I knew .NET, so it took some getting used to when I began using BackgroundWorkers. Matt Davis has summarized the difference with great excellence, but I would add that it's more difficult to comprehend exactly what the code is doing, and this can make debugging harder. It's easier to think about creating and shutting down threads, IMO, than it is to think about giving work to a pool of threads.

I still can't comment other people's posts, so forgive my momentary lameness in using an answer to address piers7

Don't use Thread.Abort(); instead, signal an event and design your thread to end gracefully when signaled. Thread.Abort() raises a ThreadAbortException at an arbitrary point in the thread's execution, which can do all kinds of unhappy things like orphan Monitors, corrupt shared state, and so on.

Configure Log4net to write to multiple files

Vinay is correct. In answer to your comment in his answer, one way you can do it is as follows:

    <level value="ALL" />
    <appender-ref ref="File1Appender" />
<logger name="SomeName">
    <level value="ALL" />
    <appender-ref ref="File1Appender2" />

This is how I have done it in the past. Then something like this for the other log:

private static readonly ILog otherLog = LogManager.GetLogger("SomeName");

And you can get your normal logger as follows:

private static readonly ILog log = LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType);

Read the loggers and appenders section of the documentation to understand how this works.

Programmatically navigate to another view controller/scene

In addition to the good answers above to set the navigation view controller on top of your screen on your app, you can add it to your AppDelegate.swift file inside the block as follows

 func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {

    window = UIWindow()
    window?.rootViewController = UINavigationController(rootViewController: LoginViewController())

    return true


How to pass data in the ajax DELETE request other than headers

I was able to successfully pass through the data attribute in the ajax method. Here is my code

     url: "/api/Gigs/Cancel",
     type: "DELETE",
     data: {
             "GigId": link.attr('data-gig-id')


The link.attr method simply returned the value of 'data-gig-id' .

How do I suspend painting for a control and its children?

At my previous job we struggled with getting our rich UI app to paint instantly and smoothly. We were using standard .Net controls, custom controls and devexpress controls.

After a lot of googling and reflector usage I came across the WM_SETREDRAW win32 message. This really stops controls drawing whilst you update them and can be applied, IIRC to the parent/containing panel.

This is a very very simple class demonstrating how to use this message:

class DrawingControl
    public static extern int SendMessage(IntPtr hWnd, Int32 wMsg, bool wParam, Int32 lParam);

    private const int WM_SETREDRAW = 11; 

    public static void SuspendDrawing( Control parent )
        SendMessage(parent.Handle, WM_SETREDRAW, false, 0);

    public static void ResumeDrawing( Control parent )
        SendMessage(parent.Handle, WM_SETREDRAW, true, 0);

There are fuller discussions on this - google for C# and WM_SETREDRAW, e.g.

C# Jitter

Suspending Layouts

And to whom it may concern, this is similar example in VB:

Public Module Extensions
    Private Function SendMessage(ByVal hWnd As IntPtr, ByVal Msg As Integer, ByVal wParam As Boolean, ByVal lParam As IntPtr) As Integer
    End Function

    Private Const WM_SETREDRAW As Integer = 11

    ' Extension methods for Control
    Public Sub ResumeDrawing(ByVal Target As Control, ByVal Redraw As Boolean)
        SendMessage(Target.Handle, WM_SETREDRAW, True, 0)
        If Redraw Then
        End If
    End Sub

    Public Sub SuspendDrawing(ByVal Target As Control)
        SendMessage(Target.Handle, WM_SETREDRAW, False, 0)
    End Sub

    Public Sub ResumeDrawing(ByVal Target As Control)
        ResumeDrawing(Target, True)
    End Sub
End Module

Eclipse returns error message "Java was started but returned exit code = 1"

I've encountered similar problems. The reason is that the path to my eclipse includes Chinese characters. Once those characters are deleted, the problem is solved. Please check if there are characters other than English in your path.

Ruby on Rails. How do I use the Active Record .build method in a :belongs to relationship?

Where it is documented:

From the API documentation under the has_many association in "Module ActiveRecord::Associations::ClassMethods" = {}, …) Returns one or more new objects of the collection type that have been instantiated with attributes and linked to this object through a foreign key, but have not yet been saved. Note: This only works if an associated object already exists, not if it‘s nil!

The answer to building in the opposite direction is a slightly altered syntax. In your example with the dogs,

Class Dog
   has_many :tags
   belongs_to :person

Class Person
  has_many :dogs

d =
d.build_person(:attributes => "go", :here => "like normal")

or even

t =
t.build_dog(:name => "Rover", :breed => "Maltese")

You can also use create_dog to have it saved instantly (much like the corresponding "create" method you can call on the collection)

How is rails smart enough? It's magic (or more accurately, I just don't know, would love to find out!)

Limiting the number of characters in a JTextField

Here is an optimized version of npinti's answer:

import javax.swing.text.AttributeSet;
import javax.swing.text.BadLocationException;
import javax.swing.text.JTextComponent;
import javax.swing.text.PlainDocument;
import java.awt.*;

public class TextComponentLimit extends PlainDocument
    private int charactersLimit;

    private TextComponentLimit(int charactersLimit)
        this.charactersLimit = charactersLimit;

    public void insertString(int offset, String input, AttributeSet attributeSet) throws BadLocationException
        if (isAllowed(input))
            super.insertString(offset, input, attributeSet);
        } else

    private boolean isAllowed(String string)
        return (getLength() + string.length()) <= charactersLimit;

    public static void addTo(JTextComponent textComponent, int charactersLimit)
        TextComponentLimit textFieldLimit = new TextComponentLimit(charactersLimit);

To add a limit to your JTextComponent, simply write the following line of code:

JTextFieldLimit.addTo(myTextField, myMaximumLength);

Embedding a media player in a website using HTML

Here is a solution to make an accessible audio player with valid xHTML and non-intrusive javascript thanks to W3C Web Audio API :

What to do :

  1. If the browser is able to read, then we display controls
  2. If the browser is not able to read, we just render a link to the file

First of all, we check if the browser implements Web Audio API:

if (typeof Audio === 'undefined') {
    // abort

Then we instanciate an Audio object:

var player = new Audio('mysong.ogg');

Then we can check if the browser is able to decode this type of file :

if(!player.canPlayType('audio/ogg')) {
    // abort

Or even if it can play the codec :

if(!player.canPlayType('audio/ogg; codecs="vorbis"')) {
    // abort

Then we can use, player.pause();

I have done a tiny JQuery plugin that I called nanodio to test this.

You can check how it works on my demo page (sorry, but text is in french :p )

Just click on a link to play, and click again to pause. If the browser can read it natively, it will. If it can't, it should download the file.

This is just a little example, but you can improve it to use any element of your page as a control button or generate ones on the fly with javascript... Whatever you want.

What is the difference between, and localhost?

In current version of Jekyll, it defaults to
This is good, if you are connected to a network but do not want anyone else to access your application.

However it may happen that you want to see how your application runs on a mobile or from some other laptop/computer.

In that case, you can use

jekyll serve --host

This binds your application to the host & next use following to connect to it from some other host

http://host's IP adress/4000 

How to add an Android Studio project to GitHub

If you are using the latest version of Android studio. then you don't need to install additional software for Git other than GIT itself -


  1. Create an account on Github -
  2. Install Git
  3. Open your working project in Android studio
  4. GoTo - File -> Settings -> Version Controll -> GitHub
  5. Enter Login and Password which you have created just on Git Account and click on test
  6. Once all credentials are true - it shows Success message. o.w Invalid Cred.
  7. Now click on VCS in android studio menu bar
  8. Select Import into Version Control -> Share Project on GitHub
  9. The popup dialog will occure contains all your files with check mark, do ok or commit all
  10. At next time whenever you want to push your project just click on VCS - > Commit Changes -> Commmit and Push.

That's it. You can find your project on your github now

Is it possible to embed animated GIFs in PDFs?

I haven't tested it but apparently you can add quicktime animations to a pdf (no idea why). So the solution would be to export the animated gif to quicktime and add it to the pdf.

Here the solution that apparently works:

  1. Open the GIF in Quicktime and save as MOV (Apparently it works with other formats too, you'll have to try it out).
  2. Insert the MOV into the PDF (with Adobe InDesign (make sure to set Object> Interactive> film options > Embed in PDF) - It should work with Adobe Acrobat Pro DC too: see link
  3. Save the PDF.

See this link (German)

Convert a dataframe to a vector (by rows)

You can try this to get your combination:

as.numeric(rbind(test$x, test$y))

which will return:

26, 34, 21, 29, 20, 28

jQuery: select an element's class and id at the same time?

It will work when adding space between id and class identifier

$("#countery .save")...

auto run a bat script in windows 7 at login

To run the batch file when the VM user logs in:

Drag the shortcut--the one that's currently on your desktop--(or the batch file itself) to Start - All Programs - Startup. Now when you login as that user, it will launch the batch file.

Another way to do the same thing is to save the shortcut or the batch file in %AppData%\Microsoft\Windows\Start Menu\Programs\Startup\.

As far as getting it to run full screen, it depends a bit what you mean. You can have it launch maximized by editing your batch file like this:

start "" /max "C:\Program Files\Oracle\VirtualBox\VirtualBox.exe" --comment "VM" --startvm "12dada4d-9cfd-4aa7-8353-20b4e455b3fa"

But if VirtualBox has a truly full-screen mode (where it hides even the taskbar), you'll have to look for a command-line parameter on VirtualBox.exe. I'm not familiar with that product.

jquery - is not a function error

When converting an ASP.Net webform prototype to a MVC site I got these errors:

TypeError: $(...).accordion is not a function

TypeError: $(...).dialog is not a function

It worked fine in the webforms. The problem/solution was this line in the _Layout.cshtml


Comment it out to see if the errors go away. Then fix it in the BundlesConfig:

bundles.Add(new ScriptBundle("~/bundles/jquery").Include(

How to set -source 1.7 in Android Studio and Gradle

You can change it in new Android studio version(0.8.X)

FIle-> Other Settings -> Default Settings -> Compiler (Expand it by clicking left arrow) -> Java Compiler -> You can change the Project bytecode version here

enter image description here

Setting up PostgreSQL ODBC on Windows

Please note that you must install the driver for the version of your software client(MS access) not the version of the OS. that's mean that if your MS Access is a 32-bits version,you must install a 32-bit odbc driver. regards

How do I execute code AFTER a form has loaded?

You could also try putting your code in the Activated event of the form, if you want it to occur, just when the form is activated. You would need to put in a boolean "has executed" check though if it is only supposed to run on the first activation.

Log record changes in SQL server in an audit table

This is the code with two bug fixes. The first bug fix was mentioned by Royi Namir in the comment on the accepted answer to this question. The bug is described on StackOverflow at Bug in Trigger Code. The second one was found by @Fandango68 and fixes columns with multiples words for their names.

ON [dbo].[person]
           DECLARE @bit            INT,
                   @field          INT,
                   @maxfield       INT,
                   @char           INT,
                   @fieldname      VARCHAR(128),
                   @TableName      VARCHAR(128),
                   @PKCols         VARCHAR(1000),
                   @sql            VARCHAR(2000),
                   @UpdateDate     VARCHAR(21),
                   @UserName       VARCHAR(128),
                   @Type           CHAR(1),
                   @PKSelect       VARCHAR(1000)

           --You will need to change @TableName to match the table to be audited.
           -- Here we made GUESTS for your example.
           SELECT @TableName = 'PERSON'

           SELECT @UserName = SYSTEM_USER,
                  @UpdateDate = CONVERT(NVARCHAR(30), GETDATE(), 126)

           -- Action
           IF EXISTS (
                  SELECT *
                  FROM   INSERTED
               IF EXISTS (
                      SELECT *
                      FROM   DELETED
                   SELECT @Type = 'U'
                   SELECT @Type = 'I'
               SELECT @Type = 'D'

           -- get list of columns
           SELECT * INTO #ins
           FROM   INSERTED

           SELECT * INTO #del
           FROM   DELETED

           -- Get primary key columns for full outer join
           SELECT @PKCols = COALESCE(@PKCols + ' and', ' on') 
                  + ' i.[' + c.COLUMN_NAME + '] = d.[' + c.COLUMN_NAME + ']'
           WHERE  pk.TABLE_NAME = @TableName
                  AND c.TABLE_NAME = pk.TABLE_NAME

           -- Get primary key select for insert
           SELECT @PKSelect = COALESCE(@PKSelect + '+', '') 
                  + '''<[' + COLUMN_NAME 
                  + ']=''+convert(varchar(100),
           coalesce(i.[' + COLUMN_NAME + '],d.[' + COLUMN_NAME + ']))+''>'''
           WHERE  pk.TABLE_NAME = @TableName
                  AND c.TABLE_NAME = pk.TABLE_NAME

           IF @PKCols IS NULL
               RAISERROR('no PK on table %s', 16, -1, @TableName)


           SELECT @field = 0,
                  -- @maxfield = MAX(COLUMN_NAME) 
                  @maxfield = -- FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_NAME = @TableName

                          OBJECT_ID(TABLE_SCHEMA + '.' + @TableName),
           WHERE  TABLE_NAME = @TableName

           WHILE @field < @maxfield
               SELECT @field = MIN(
                              OBJECT_ID(TABLE_SCHEMA + '.' + @TableName),
               WHERE  TABLE_NAME = @TableName
                      AND COLUMNPROPERTY(
                              OBJECT_ID(TABLE_SCHEMA + '.' + @TableName),
                          ) > @field

               SELECT @bit = (@field - 1)% 8 + 1

               SELECT @bit = POWER(2, @bit - 1)

               SELECT @char = ((@field - 1) / 8) + 1

               IF SUBSTRING(COLUMNS_UPDATED(), @char, 1) & @bit > 0
                  OR @Type IN ('I', 'D')
                   SELECT @fieldname = COLUMN_NAME
                   WHERE  TABLE_NAME = @TableName
                          AND COLUMNPROPERTY(
                                  OBJECT_ID(TABLE_SCHEMA + '.' + @TableName),
                              ) = @field

                   SELECT @sql = 
           insert into Audit (    Type, 
           select ''' + @Type + ''',''' 
                          + @TableName + ''',' + @PKSelect
                          + ',''' + @fieldname + ''''
                          + ',convert(varchar(1000),d.' + @fieldname + ')'
                          + ',convert(varchar(1000),i.' + @fieldname + ')'
                          + ',''' + @UpdateDate + ''''
                          + ',''' + @UserName + ''''
                          + ' from #ins i full outer join #del d'
                          + @PKCols
                          + ' where i.' + @fieldname + ' <> d.' + @fieldname 
                          + ' or (i.' + @fieldname + ' is null and  d.'
                          + @fieldname
                          + ' is not null)' 
                          + ' or (i.' + @fieldname + ' is not null and  d.' 
                          + @fieldname
                          + ' is null)' 

                   EXEC (@sql)

Test if registry value exists

Personally, I do not like test functions having a chance of spitting out errors, so here is what I would do. This function also doubles as a filter that you can use to filter a list of registry keys to only keep the ones that have a certain key.

Function Test-RegistryValue {
        [Parameter(Position = 0, Mandatory = $true, ValueFromPipeline = $true, ValueFromPipelineByPropertyName = $true)]
        [Parameter(Position = 1, Mandatory = $true)]

    process {
        if (Test-Path $Path) {
            $Key = Get-Item -LiteralPath $Path
            if ($Key.GetValue($Name, $null) -ne $null) {
                if ($PassThru) {
                    Get-ItemProperty $Path $Name
                } else {
            } else {
        } else {

Python+OpenCV: cv2.imwrite

wtluo, great ! May I propose a slight modification of your code 2. ? Here it is:

for i, detected_box in enumerate(detect_boxes):
    box = detected_box["box"]
    face_img = img[ box[1]:box[1] + box[3], box[0]:box[0] + box[2] ]
    cv2.imwrite("face-{:03d}.jpg".format(i+1), face_img)

Selecting Multiple Values from a Dropdown List in Google Spreadsheet

I have found solution at

You would need to use Tools > Script Editor. Create .gs and .html files there. See example at (link can be also found under Youtube video). Just copy

Once you have .gs and .html files in place save them and reload your spreadsheet. You will see "Custom menu" as the last item of your top menu. Select cell you would like to manage and click on this menu item.

During the first time it will ask you to authorize application - go ahead and do this.

Note (1): make sure that your cell has "Data validation" defined before you click on "Custom menu".

Note (2): it appeared that solution works with "List from a range" criteria for Data validation (it does not work with "List of items")

Running .sh scripts in Git Bash

If your running export command in your bash script the above-given solution may not export anything even if it will run the script. As an alternative for that, you can run your script using


Now if you try to echo your var it will be shown. Check my the result on my git bash

(coffeeapp) user (master *) capstone
$ .
(coffeeapp) user (master *) capstone
(coffeeapp) user (master *) capstone

Check more detail in this question

How to search for a string in text files?

if True:
    print "true"

This always happens because True is always True.

You want something like this:

if check():
    print "true"
    print "false"

Good luck!

How to remove td border with html?


<table border="1">
      <table border="">

Using Jquery Datatable with AngularJs

After many hours of experimenting with using jQueryDataTables with Angular, I found what I needed was available with a native Angular directive called ng-table. It provides sorting, pagination, and ajax reloads (sort of lazy loading capable with a few tweaks).

Build .so file from .c file using gcc command line

To generate a shared library you need first to compile your C code with the -fPIC (position independent code) flag.

gcc -c -fPIC hello.c -o hello.o

This will generate an object file (.o), now you take it and create the .so file:

gcc hello.o -shared -o

EDIT: Suggestions from the comments:

You can use

gcc -shared -o -fPIC hello.c

to do it in one step. – Jonathan Leffler

I also suggest to add -Wall to get all warnings, and -g to get debugging information, to your gcc commands. – Basile Starynkevitch

Simple and clean way to convert JSON string to Object in Swift

Here's a sample for you to make things simpler and easier. My String data in my database is a JSON file that looks like this:

[{"stype":"noun","sdsc":"careless disregard for consequences","swds":"disregard, freedom, impulse, licentiousness, recklessness, spontaneity, thoughtlessness, uninhibitedness, unrestraint, wantonness, wildness","anwds":"restraint, self-restraint"},{"stype":"verb","sdsc":"leave behind, relinquish","swds":"abdicate, back out, bail out, bow out, chicken out, cop out, cut loose, desert, discard, discontinue, ditch, drop, drop out, duck, dump, dust, flake out, fly the coop, give up the ship, kiss goodbye, leave, leg it, let go, opt out, pull out, quit, run out on, screw, ship out, stop, storm out, surrender, take a powder, take a walk, throw over, vacate, walk out on, wash hands of, withdraw, yield","anwds":"adopt, advance, allow, assert, begin, cherish, come, continue, defend, favor, go, hold, keep, maintain, persevere, pursue, remain, retain, start, stay, support, uphold"},{"stype":"verb","sdsc":"leave in troubled state","swds":"back out, desert, disown, forsake, jilt, leave, leave behind, quit, reject, renounce, throw over, walk out on","anwds":"adopt, allow, approve, assert, cherish, come, continue, defend, favor, keep, pursue, retain, stay, support, uphold"}]

To load this JSON String Data, follow these simple Steps. First, create a class for my MoreData Object like this:

class  MoreData {
public private(set) var stype : String
public private(set) var sdsc : String
public private(set) var swds : String
public private(set) var anwds : String

init( stype : String, sdsc : String, swds : String, anwds : String) {

    self.stype = stype
    self.sdsc = sdsc
    self.swds = swds
    self.anwds = anwds

Second, create my String extension for my JSON String like this:

extension  String {
func toJSON() -> Any? {
    guard let data = .utf8, allowLossyConversion: false) else { return nil }
    return try? JSONSerialization.jsonObject(with: data, options: .mutableContainers)

Third, create My Srevices Class to handle my String Data like this:

class Services {
static let instance: Services = Services()

func loadMoreDataByString(byString: String) -> [MoreData]{
    var  myVariable = [MoreData]()

    guard let ListOf = byString.toJSON() as? [[String: AnyObject]] else { return  [] }

    for object in ListOf {
        let stype  = object["stype"] as? String ?? ""
        let sdsc  = object["sdsc"] as? String ?? ""
         let swds  = object["swds"] as? String ?? ""
        let anwds  = object["anwds"] as? String ?? ""

        let myMoreData = MoreData(stype : stype, sdsc : sdsc, swds : swds, anwds : anwds)
    return myVariable

Finally, call this Function from the View Controller to load data in the table view like this:

    func handlingJsonStringData(){
    moreData.removeAll(keepingCapacity: false)
    moreData =  Services.instance.loadMoreDataByString(byString: jsonString)

How to evaluate a math expression given in string form?

if we are going to implement it then we can can use the below algorithm :--

  1. While there are still tokens to be read in,

    1.1 Get the next token. 1.2 If the token is:

    1.2.1 A number: push it onto the value stack.

    1.2.2 A variable: get its value, and push onto the value stack.

    1.2.3 A left parenthesis: push it onto the operator stack.

    1.2.4 A right parenthesis:

     1 While the thing on top of the operator stack is not a 
       left parenthesis,
         1 Pop the operator from the operator stack.
         2 Pop the value stack twice, getting two operands.
         3 Apply the operator to the operands, in the correct order.
         4 Push the result onto the value stack.
     2 Pop the left parenthesis from the operator stack, and discard it.

    1.2.5 An operator (call it thisOp):

     1 While the operator stack is not empty, and the top thing on the
       operator stack has the same or greater precedence as thisOp,
       1 Pop the operator from the operator stack.
       2 Pop the value stack twice, getting two operands.
       3 Apply the operator to the operands, in the correct order.
       4 Push the result onto the value stack.
     2 Push thisOp onto the operator stack.
  2. While the operator stack is not empty, 1 Pop the operator from the operator stack. 2 Pop the value stack twice, getting two operands. 3 Apply the operator to the operands, in the correct order. 4 Push the result onto the value stack.

  3. At this point the operator stack should be empty, and the value stack should have only one value in it, which is the final result.

Image overlay on responsive sized images bootstrap

<div class="col-md-4 py-3 pic-card">
          <div class="card ">
          <div class="pic-overlay"></div>
          <img class="img-fluid " src="images/Site Images/Health & Fitness-01.png" alt="">
          <div class="centeredcard">
              <span class="card-headings">HEALTH & FITNESS</span>
            <div class="content-inner mt-5">
              <p class="lead  p-overlay">Lorem ipsum dolor sit amet, consectetur adipisicing elit. Recusandae ipsam nemo quasi quo quae voluptate.</p>

     position: relative;


    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    position: absolute;
    transition: background-color 0.5s ease;

    position: relative;
     display: none;

        background-color: $dark-overlay;


         display: block;
         cursor: pointer;

        font-size: 15px;
        padding: 0;

        content: '';
        width: 80%;
        border-bottom: solid 2px  rgb(52, 178, 179);
        position: absolute;
        left: 5%;
        top: 25%;
        z-index: 1;
         font-size: 15px;

enter code here

How to select a radio button by default?

Use the checked attribute.

<input type="radio" name="imgsel"  value="" checked /> 


<input type="radio" name="imgsel"  value="" checked="checked" /> 

Keras model.summary() result - Understanding the # of Parameters

For Dense Layers:

output_size * (input_size + 1) == number_parameters 

For Conv Layers:

output_channels * (input_channels * window_size + 1) == number_parameters

Consider following example,

model = Sequential([
Conv2D(32, (3, 3), activation='relu', input_shape=input_shape),
Conv2D(64, (3, 3), activation='relu'),
Conv2D(128, (3, 3), activation='relu'),
Dense(num_classes, activation='softmax')

Layer (type)                 Output Shape              Param #   
conv2d_1 (Conv2D)            (None, 222, 222, 32)      896       
conv2d_2 (Conv2D)            (None, 220, 220, 64)      18496     
conv2d_3 (Conv2D)            (None, 218, 218, 128)     73856     
dense_9 (Dense)              (None, 218, 218, 10)      1290      

Calculating params,

assert 32 * (3 * (3*3) + 1) == 896
assert 64 * (32 * (3*3) + 1) == 18496
assert 128 * (64 * (3*3) + 1) == 73856
assert num_classes * (128 + 1) == 1290

Swift double to string

Swift 3+: Try these line of code

let num: Double = 1.5

let str = String(format: "%.2f", num)

SQL Server AS statement aliased column within WHERE statement

SQL doesn't typically allow you to reference column aliases in WHERE, GROUP BY or HAVING clauses. MySQL does support referencing column aliases in the GROUP BY and HAVING, but I stress that it will cause problems when porting such queries to other databases.

When in doubt, use the actual column name:

SELECT AS latitude 
  FROM poi_table t
 WHERE < 500

I added a table alias to make it easier to see what is an actual column vs alias.


A computed column, like the one you see here:

       ( 6371*1000 * acos( cos( radians(42.3936868308) ) * cos( radians( lat ) ) * cos( radians( lon ) - radians(-72.5277256966) ) + sin( radians(42.3936868308) ) * sin( radians( lat ) ) ) ) AS distance
  FROM poi_table 
 WHERE distance < 500;

...doesn't change that you can not reference a column alias in the WHERE clause. For that query to work, you'd have to use:

       ( 6371*1000 * acos( cos( radians(42.3936868308) ) * cos( radians( lat ) ) * cos( radians( lon ) - radians(-72.5277256966) ) + sin( radians(42.3936868308) ) * sin( radians( lat ) ) ) ) AS distance
  FROM poi_table
 WHERE ( 6371*1000 * acos( cos( radians(42.3936868308) ) * cos( radians( lat ) ) * cos( radians( lon ) - radians(-72.5277256966) ) + sin( radians(42.3936868308) ) * sin( radians( lat ) ) ) ) < 500;

Be aware that using a function on a column (IE: RADIANS(lat)) will render an index useless, if one exists on the column.

How to execute a JavaScript function when I have its name as a string

Could you not just do this:

var codeToExecute = "My.Namespace.functionName()";
var tmpFunc = new Function(codeToExecute);

You can also execute any other JavaScript using this method.

How can I specify a [DllImport] path at runtime?

Contrary to the suggestions by some of the other answers, using the DllImport attribute is still the correct approach.

I honestly don't understand why you can't do just like everyone else in the world and specify a relative path to your DLL. Yes, the path in which your application will be installed differs on different people's computers, but that's basically a universal rule when it comes to deployment. The DllImport mechanism is designed with this in mind.

In fact, it isn't even DllImport that handles it. It's the native Win32 DLL loading rules that govern things, regardless of whether you're using the handy managed wrappers (the P/Invoke marshaller just calls LoadLibrary). Those rules are enumerated in great detail here, but the important ones are excerpted here:

Before the system searches for a DLL, it checks the following:

  • If a DLL with the same module name is already loaded in memory, the system uses the loaded DLL, no matter which directory it is in. The system does not search for the DLL.
  • If the DLL is on the list of known DLLs for the version of Windows on which the application is running, the system uses its copy of the known DLL (and the known DLL's dependent DLLs, if any). The system does not search for the DLL.

If SafeDllSearchMode is enabled (the default), the search order is as follows:

  1. The directory from which the application loaded.
  2. The system directory. Use the GetSystemDirectory function to get the path of this directory.
  3. The 16-bit system directory. There is no function that obtains the path of this directory, but it is searched.
  4. The Windows directory. Use the GetWindowsDirectory function to get the path of this directory.
  5. The current directory.
  6. The directories that are listed in the PATH environment variable. Note that this does not include the per-application path specified by the App Paths registry key. The App Paths key is not used when computing the DLL search path.

So, unless you're naming your DLL the same thing as a system DLL (which you should obviously not be doing, ever, under any circumstances), the default search order will start looking in the directory from which your application was loaded. If you place the DLL there during the install, it will be found. All of the complicated problems go away if you just use relative paths.

Just write:

[DllImport("MyAppDll.dll")] // relative path; just give the DLL's name
static extern bool MyGreatFunction(int myFirstParam, int mySecondParam);

But if that doesn't work for whatever reason, and you need to force the application to look in a different directory for the DLL, you can modify the default search path using the SetDllDirectory function.
Note that, as per the documentation:

After calling SetDllDirectory, the standard DLL search path is:

  1. The directory from which the application loaded.
  2. The directory specified by the lpPathName parameter.
  3. The system directory. Use the GetSystemDirectory function to get the path of this directory.
  4. The 16-bit system directory. There is no function that obtains the path of this directory, but it is searched.
  5. The Windows directory. Use the GetWindowsDirectory function to get the path of this directory.
  6. The directories that are listed in the PATH environment variable.

So as long as you call this function before you call the function imported from the DLL for the first time, you can modify the default search path used to locate DLLs. The benefit, of course, is that you can pass a dynamic value to this function that is computed at run-time. That isn't possible with the DllImport attribute, so you will still use a relative path (the name of the DLL only) there, and rely on the new search order to find it for you.

You'll have to P/Invoke this function. The declaration looks like this:

[DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)]
static extern bool SetDllDirectory(string lpPathName);

How to get a list of properties with a given attribute?

var props = t.GetProperties().Where(
                prop => Attribute.IsDefined(prop, typeof(MyAttribute)));

This avoids having to materialize any attribute instances (i.e. it is cheaper than GetCustomAttribute[s]().

Delete all rows in table

Truncate table is faster than delete * from XXX. Delete is slow because it works one row at a time. There are a few situations where truncate doesn't work, which you can read about on MSDN.

How do I convert an interval into a number of hours with postgres?

Probably the easiest way is:

SELECT EXTRACT(epoch FROM my_interval)/3600

How to loop through elements of forms with JavaScript?

You can iterate named fields somehow like this:

let jsonObject = {};
for(let field of form.elements) {
  if ( {
      jsonObject[] = field.value;

Or, if you need only submiting fields:

function formDataToJSON(form) {
  let jsonObject = {};
  let formData = new FormData(form);
  for(let field of formData) {
      jsonObject[field[0]] = field[1];
  return JSON.stringify(jsonObject);

How to convert an ASCII character into an int in C

What about:

int a_as_int = (int)'a';

Best way to convert pdf files to tiff files

I wrote a little powershell script to go through a directory structure and convert all pdf files to tiff files using ghostscript. Here is my script:

$tool = 'C:\Program Files\gs\gs8.63\bin\gswin32c.exe'
$pdfs = get-childitem . -recurse | where {$_.Extension -match "pdf"}

foreach($pdf in $pdfs)

    $tiff = $pdf.FullName.split('.')[0] + '.tiff'
    if(test-path $tiff)
        "tiff file already exists " + $tiff
        'Processing ' + $pdf.Name        
        $param = "-sOutputFile=$tiff"
        & $tool -q -dNOPAUSE -sDEVICE=tiffg4 $param -r300 $pdf.FullName -c quit

How do I add a Fragment to an Activity with a programmatically created content view

It turns out there's more than one problem with that code. A fragment cannot be declared that way, inside the same java file as the activity but not as a public inner class. The framework expects the fragment's constructor (with no parameters) to be public and visible. Moving the fragment into the Activity as an inner class, or creating a new java file for the fragment fixes that.

The second issue is that when you're adding a fragment this way, you must pass a reference to the fragment's containing view, and that view must have a custom id. Using the default id will crash the app. Here's the updated code:

public class DebugExampleTwo extends Activity {

    private static final int CONTENT_VIEW_ID = 10101010;

    protected void onCreate(Bundle savedInstanceState) {
        FrameLayout frame = new FrameLayout(this);
        setContentView(frame, new LayoutParams(
            LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT));

        if (savedInstanceState == null) {
            Fragment newFragment = new DebugExampleTwoFragment();
            FragmentTransaction ft = getFragmentManager().beginTransaction();
            ft.add(CONTENT_VIEW_ID, newFragment).commit();

    public static class DebugExampleTwoFragment extends Fragment {
        public View onCreateView(LayoutInflater inflater, ViewGroup container,
                Bundle savedInstanceState) {
            EditText v = new EditText(getActivity());
            v.setText("Hello Fragment!");
            return v;

How to copy a string of std::string type in C++?

You shouldn't use strcpy() to copy a std::string, only use it for C-Style strings.

If you want to copy a to b then just use the = operator.

string a = "text";
string b = "image";
b = a;

Generate an integer sequence in MySQL

This query generates numbers from 0 to 1023. I believe it would work in any sql database flavor:

    as i
               (select 0 as i union select 1) as i0
    cross join (select 0 as i union select 1) as i1
    cross join (select 0 as i union select 1) as i2
    cross join (select 0 as i union select 1) as i3
    cross join (select 0 as i union select 1) as i4
    cross join (select 0 as i union select 1) as i5
    cross join (select 0 as i union select 1) as i6
    cross join (select 0 as i union select 1) as i7
    cross join (select 0 as i union select 1) as i8
    cross join (select 0 as i union select 1) as i9

Java: splitting a comma-separated string but ignoring commas in quotes

I would do something like this:

boolean foundQuote = false;

if(charAtIndex(currentStringIndex) == '"')
   foundQuote = true;

if(foundQuote == true)
   //do nothing


  string[] split = currentString.split(',');  

What is the purpose of class methods?

Honestly? I've never found a use for staticmethod or classmethod. I've yet to see an operation that can't be done using a global function or an instance method.

It would be different if python used private and protected members more like Java does. In Java, I need a static method to be able to access an instance's private members to do stuff. In Python, that's rarely necessary.

Usually, I see people using staticmethods and classmethods when all they really need to do is use python's module-level namespaces better.

Name node is in safe mode. Not able to leave

Try this

sudo -u hdfs hdfs dfsadmin -safemode leave

check status of safemode

sudo -u hdfs hdfs dfsadmin -safemode get

If it is still in safemode ,then one of the reason would be not enough space in your node, you can check your node disk usage using :

df -h

if root partition is full, delete files or add space in your root partition and retry first step.

How to increase heap size for jBoss server

On wildfly 8 and later, go to /bin/standalone.conf and put your JAVA_OPTS there, with all you need.

Select first and last row from grouped data

Just for completeness: You can pass slice a vector of indices:

df %>% arrange(stopSequence) %>% group_by(id) %>% slice(c(1,n()))

which gives

  id stopId stopSequence
1  1      a            1
2  1      c            3
3  2      b            1
4  2      c            4
5  3      b            1
6  3      a            3

How to present UIActionSheet iOS Swift?






Code (tested)

let alert = UIAlertController()

        let width: Int = Int(UIScreen.main.bounds.width - 100)

        let viewAction    =     UIAlertAction(title: "View", style: .default , handler:{ (UIAlertAction)in
                                    let storyboard      =   UIStoryboard(name: "Main", bundle: nil)
                                    let orderDetailVC   =   storyboard.instantiateViewController(withIdentifier: "orderDetail") as! OrderDetailTableViewController

                                    orderDetailVC.orderId     =   self.myDraftOrders[indexPath.row]["id"].intValue

                                    self.navigationController?.pushViewController(orderDetailVC, animated: true)

        viewAction.setValue(appGreenColor, forKey: "titleTextColor")


        let modifyAction    =   UIAlertAction(title: "Modify", style: .default, handler:{ (UIAlertAction)in
                                    showAlert("Coming soon...")

        modifyAction.setValue(appCyanColor, forKey: "titleTextColor")


        let copyAction      =   UIAlertAction(title: "Copy", style: .default, handler:{ (UIAlertAction)in

                                    self.copyOrder(orderId: self.myDraftOrders[indexPath.row]["id"].intValue)


        copyAction.setValue(appBlueColor, forKey: "titleTextColor")


        alert.addAction(UIAlertAction(title: "Delete", style: .destructive , handler:{ (UIAlertAction)in

            self.deleteOrder(orderId: self.myDraftOrders[indexPath.row]["id"].intValue, indexPath: indexPath)


        alert.addAction(UIAlertAction(title: "Cancel", style: .cancel, handler:{ (UIAlertAction)in
            print("User click Dismiss button")


        let popover = alert.popoverPresentationController

        popover?.delegate = self

        let cellT = tableView.cellForRow(at: indexPath)

        popover?.sourceView =   cellT
        popover?.sourceRect =   CGRect(x: width, y: 25, width: 100, height: 50)
        present(alert, animated: true)

How can I submit form on button click when using preventDefault()?

Ok, first e.preventDefault(); it's not a Jquery element, it's a method of javascript, now what it's true it's if you add this method you avoid the submit the event, now what you could do it's send the form by ajax something like this

     url: $(this).attr('action'),
     data : $(this).serialize(),
     success : function (data){



In your specific example they are the same, because the optimizer has figured out what you are trying to do is the same in both examples. But it is possible that in non-trivial examples the optimizer may not do this, and in that case there are reasons to prefer one to other on occasion.

NOT IN should be preferred if you are testing multiple rows in your outer select. The subquery inside the NOT IN statement can be evaluated at the beginning of the execution, and the temporary table can be checked against each value in the outer select, rather than re-running the subselect every time as would be required with the NOT EXISTS statement.

If the subquery must be correlated with the outer select, then NOT EXISTS may be preferable, since the optimizer may discover a simplification that prevents the creation of any temporary tables to perform the same function.

Difference between chr(13) and chr(10)

Chr(10) is the Line Feed character and Chr(13) is the Carriage Return character.

You probably won't notice a difference if you use only one or the other, but you might find yourself in a situation where the output doesn't show properly with only one or the other. So it's safer to include both.

Historically, Line Feed would move down a line but not return to column 1:


Similarly Carriage Return would return to column 1 but not move down a line:


Paste this into a text editor and then choose to "show all characters", and you'll see both characters present at the end of each line. Better safe than sorry.

How to remove old and unused Docker images

I recently wrote a script to solve this on one of my servers:


# Remove all the dangling images
DANGLING_IMAGES=$(docker images -qf "dangling=true")
if [[ -n $DANGLING_IMAGES ]]; then
    docker rmi "$DANGLING_IMAGES"

# Get all the images currently in use
    docker ps -a --format '{{.Image}}' | \
    sort -u | \
    uniq | \
    awk -F ':' '$2{print $1":"$2}!$2{print $1":latest"}' \

# Get all the images currently available
    docker images --format '{{.Repository}}:{{.Tag}}' | \
    sort -u \

# Remove the unused images
for i in "${ALL_IMAGES[@]}"; do
    for j in "${USED_IMAGES[@]}"; do
        if [[ "$i" == "$j" ]]; then
    if [[ "$UNUSED" == true ]]; then
        docker rmi "$i"

Register .NET Framework 4.5 in IIS 7.5

You can find the aspnet_regiis in the following directory:


Go to the directory and run the command form there. I guess the path is missing in your PATH variable.

import httplib ImportError: No module named httplib

If you use PyCharm, please change you 'Project Interpreter' to '2.7.x'

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