Programs & Examples On #Bootstrapper

Bootstrappers are programs that run a sequence of installation packages one after another. This is often needed when a product has to have certain prerequisites installed.

ERROR: Sonar server 'http://localhost:9000' can not be reached

In file in conf folder I had hardcoaded ip of my machine where sobarqube was installed in property 235.22 I commented this and it started working for me.

Exception is: InvalidOperationException - The current type, is an interface and cannot be constructed. Are you missing a type mapping?

I had this problem, and the cause was that I had not added the Microsoft.Owin.Host.SystemWeb NuGet package to my project. Although the code in my startup class was correct, it was not being executed.

So if you're trying to solve this problem, put a breakpoint in the code where you do the Unity registrations. If you don't hit it, your dependency injection isn't going to work.

Can't specify the 'async' modifier on the 'Main' method of a console app

On MSDN, the documentation for Task.Run Method (Action) provides this example which shows how to run a method asynchronously from main:

using System;
using System.Threading;
using System.Threading.Tasks;

public class Example
    public static void Main()

        var t = Task.Run(() => ShowThreadInfo("Task") );

    static void ShowThreadInfo(String s)
        Console.WriteLine("{0} Thread ID: {1}",
                          s, Thread.CurrentThread.ManagedThreadId);
// The example displays the following output:
//       Application thread ID: 1
//       Task thread ID: 3

Note this statement that follows the example:

The examples show that the asynchronous task executes on a different thread than the main application thread.

So, if instead you want the task to run on the main application thread, see the answer by @StephenCleary.

And regarding the thread on which the task runs, also note Stephen's comment on his answer:

You can use a simple Wait or Result, and there's nothing wrong with that. But be aware that there are two important differences: 1) all async continuations run on the thread pool rather than the main thread, and 2) any exceptions are wrapped in an AggregateException.

(See Exception Handling (Task Parallel Library) for how to incorporate exception handling to deal with an AggregateException.)

Finally, on MSDN from the documentation for Task.Delay Method (TimeSpan), this example shows how to run an asynchronous task that returns a value:

using System;
using System.Threading.Tasks;

public class Example
    public static void Main()
        var t = Task.Run(async delegate
                    await Task.Delay(TimeSpan.FromSeconds(1.5));
                    return 42;
        Console.WriteLine("Task t Status: {0}, Result: {1}",
                          t.Status, t.Result);
// The example displays the following output:
//        Task t Status: RanToCompletion, Result: 42

Note that instead of passing a delegate to Task.Run, you can instead pass a lambda function like this:

var t = Task.Run(async () =>
            await Task.Delay(TimeSpan.FromSeconds(1.5));
            return 42;

SELECT INTO Variable in MySQL DECLARE causes syntax error?

For those running in such issues right now, just try to put an alias for the table, this should the trick, e.g:

SELECT myvalue 
  INTO myvar 
  FROM mytable x
 WHERE x.anothervalue = 1;

It worked for me.


Issue pushing new code in Github

I had a similar problem... I resolved it like this (i'm not an git expert so i don't know if it is a right solution, but it worked for me):

git pull origin master --allow-unrelated-histories
git merge origin origin/master
git rm
git commit -m 'removed'
git push origin master

node.js Error: connect ECONNREFUSED; response from server

use a proxy property in your code it should work just fine

const https = require('https');
const request = require('request');

    function (error, response, body) {
        if (!error && response.statusCode == 200) {
            var data = body;

How to find top three highest salary in emp table in oracle?

SELECT a.ename, b.sal
    FROM emp a, emp b
    WHERE a.empno = b.empno
          3 > (SELECT count(*) FROM emp b
                   WHERE a.sal = b.sal);

Without using TOP, ROWID, rank etc. Works with oldest sql also

How do I push amended commit to the remote Git repository?

I actually once pushed with --force and .git repository and got scolded by Linus BIG TIME. In general this will create a lot of problems for other people. A simple answer is "Don't do it".

I see others gave the recipe for doing so anyway, so I won't repeat them here. But here is a tip to recover from the situation after you have pushed out the amended commit with --force (or +master).

  1. Use git reflog to find the old commit that you amended (call it old, and we'll call the new commit you created by amending new).
  2. Create a merge between old and new, recording the tree of new, like git checkout new && git merge -s ours old.
  3. Merge that to your master with git merge master
  4. Update your master with the result with git push . HEAD:master
  5. Push the result out.

Then people who were unfortunate enough to have based their work on the commit you obliterated by amending and forcing a push will see the resulting merge will see that you favor new over old. Their later merges will not see the conflicts between old and new that resulted from your amending, so they do not have to suffer.

Ping all addresses in network, windows

All you are wanting to do is to see if computers are connected to the network and to gather their IP addresses. You can utilize angryIP scanner: to see what IP addresses are in use on a particular subnet or groups of subnets.

I have found this tool very helpful when trying to see what IPs are being used that are not located inside of my DHCP.

Can I have a video with transparent background using HTML5 video tag?

At this time, the only video codec that truly supports an alpha channel is VP8, which Flash uses. MP4 would probably support it if the video was exported as an image sequence, but I'm fairly certain Ogg video files have no support whatsoever for an alpha channel. This might be one of those rare instances where sticking with Flash would serve you better.

SHA1 vs md5 vs SHA256: which to use for a PHP login?

Let's assume the next point : the hackers steal our database including the users and password (encrypted). And the hackers created a fake account with a password that they know.

MD5 is weak because its short and popular and practically every hash generation without password is weak of a dictionary attack. But..

So, let's say that we are still using MD5 with a SALT. The hackers don't know the SALT but they know the password of a specific user. So they can test : ?????12345 where 12345 is the know password and ????? is the salt. The hackers sooner or later can guess the SALT.

However, if we used a MD5+SALT and we applied MD5, then there is not way to recover the information. However, i repeat, MD5 is still short.

For example, let's say that my password is : 12345. The SALT is BILLCLINTON

md5 : 827ccb0eea8a706c4c34a16891f84e7b

md5 with the hash : 56adb0f19ac0fb50194c312d49b15378

mD5 with the hash over md5 : 28a03c0bc950decdd9ee362907d1798a I tried to use those online service and i found none that was able to crack it. And its only MD5! (may be as today it will be crackeable because i generated the md5 online)

If you want to overkill then SHA256 is more than enough if its applied with a salt and twice.

tldr MD5(HASH+MD5(password)) = ok but short, SHA256 is more than enough.

How do I hide an element on a click event anywhere outside of the element?

This is made from the other solutions above.


        event.stopPropagation();    //stops the click event to go "throu" the button an hit the document
    $(document).click(function() {
    $(".interface").click(function(event) {
        return false;                                        

        <button> Press here for content</button> 
      <div class="area">
        <div class="interface"> Content</div>

Android button background color

With version 1.2.0-alpha06 of material design library, now we can use android:background="..." on MaterialButton components:


Is there a function to split a string in PL/SQL?

If APEX_UTIL is not available, you have a solution using REGEXP_SUBSTR().

Inspired from :

  MY_STRING VARCHAR2(2000) := '123,456,abc,def';
    with test as    
      (select MY_STRING from dual)
      select regexp_substr(MY_STRING, '[^,]+', 1, rownum) SPLIT
      from test
      connect by level <= length (regexp_replace(MY_STRING, '[^,]+'))  + 1)

Detecting attribute change of value of an attribute I made

You would have to watch the DOM node changes. There is an API called MutationObserver, but it looks like the support for it is very limited. This SO answer has a link to the status of the API, but it seems like there is no support for it in IE or Opera so far.

One way you could get around this problem is to have the part of the code that modifies the data-select-content-val attribute dispatch an event that you can listen to.

For example, see: on how to tie it together.

The code here is

$(function() {  
  // Here you register for the event and do whatever you need to do.
  $(document).on('data-attribute-changed', function() {
    var data = $('#contains-data').data('mydata');
    alert('Data changed to: ' + data);

  $('#button').click(function() {
    $('#contains-data').data('mydata', 'foo');
    // Whenever you change the attribute you will user the .trigger
    // method. The name of the event is arbitrary

   $('#getbutton').click(function() {
    var data = $('#contains-data').data('mydata');
    alert('Data is: ' + data);

How can I create an Asynchronous function in Javascript?

Edit: I totally misunderstood the question. In the browser, I would use setTimeout. If it was important that it ran in another thread, I would use Web Workers.

Split string into individual words Java

you can use Apache commons' StringUtils class

    String[] partsOfString = StringUtils.split("I want to walk my dog",StringUtils.SPACE)

Using TortoiseSVN how do I merge changes from the trunk to a branch and vice versa?

Take a look at It's command-line, can't be invoked by TortoiseSVN, but it's more powerful. From the FAQ:

Traditional subversion will let you merge changes, but it doesn't "remember" what you've already merged. It also doesn't provide a convenient way to exclude a change set from being merged. automates some of the work, and simplifies it. Svnmerge also creates a commit message with the log messages from all of the things it merged.

Commenting out a set of lines in a shell script

As per this site:

: '
This is a test comment
Author foo bar
Released under GNU 

echo "Init..."
# rest of script

add to array if it isn't there already

If you don't care about the ordering of the keys, you could do the following:

$array = YOUR_ARRAY
$unique = array();
foreach ($array as $a) {
    $unique[$a] = $a;

Android Studio - ADB Error - "...device unauthorized. Please check the confirmation dialog on your device."

Seems strange the intricate cable&restart solution steps ... The first time I've plugged the Android device to my Ubuntu (15.10) I've got Connect as: multimedia or camera options and in my Android Studio the device status was unauthorized. It wasn't until I choose between one of the options that I got in the Android device the PC authorization option. When you give the proper permissions in Android then the device status changed to online in Android Studio. Cheers

Render Partial View Using jQuery in ASP.NET MVC

You can't render a partial view using only jQuery. You can, however, call a method (action) that will render the partial view for you and add it to the page using jQuery/AJAX. In the below, we have a button click handler that loads the url for the action from a data attribute on the button and fires off a GET request to replace the DIV contained in the partial view with the updated contents.

$('.js-reload-details').on('click', function(evt) {

    var $detailDiv = $('#detailsDiv'),
        url = $(this).data('url');

    $.get(url, function(data) {

where the user controller has an action named details that does:

public ActionResult Details( int id )
    var model = ...get user from db using id...

    return PartialView( "UserDetails", model );

This is assuming that your partial view is a container with the id detailsDiv so that you just replace the entire thing with the contents of the result of the call.

Parent View Button

 <button data-url='@Url.Action("details","user", new { id = Model.ID } )'

User is controller name and details is action name in @Url.Action(). UserDetails partial view

<div id="detailsDiv">
    <!-- ...content... -->

How to get a shell environment variable in a makefile?

If you've exported the environment variable:

export demoPath=/usr/local/demo

you can simply refer to it by name in the makefile (make imports all the environment variables you have set):

DEMOPATH = ${demoPath}    # Or $(demoPath) if you prefer.

If you've not exported the environment variable, it is not accessible until you do export it, or unless you pass it explicitly on the command line:

make DEMOPATH="${demoPath}" …

If you are using a C shell derivative, substitute setenv demoPath /usr/local/demo for the export command.

How to prevent Browser cache on Angular 2 site?

In each html template I just add the following meta tags at the top:

<meta http-equiv="Cache-Control" content="no-cache, no-store, must-revalidate">
<meta http-equiv="Pragma" content="no-cache">
<meta http-equiv="Expires" content="0">

In my understanding each template is free standing therefore it does not inherit meta no caching rules setup in the index.html file.

Counting lines, words, and characters within a text file using Python

Try this:

fname = "feed.txt"

num_lines = 0
num_words = 0
num_chars = 0

with open(fname, 'r') as f:
    for line in f:
        words = line.split()

        num_lines += 1
        num_words += len(words)
        num_chars += len(line)

Back to your code:

fname = "feed.txt"
fname = open('feed.txt', 'r')

what's the point of this? fname is a string first and then a file object. You don't really use the string defined in the first line and you should use one variable for one thing only: either a string or a file object.

for line in feed:
    lines = line.split('\n')

line is one line from the file. It does not make sense to split('\n') it.

"Warning: iPhone apps should include an armv6 architecture" even with build config set

Try changing your deployment target to something higher than an armv6 processor. The settings for xCode are referencing the operating system level, for instance: iOS version#{3.1, 3.2, 4.0, 4.1, 4.2, 4.3, 5.0, 5.1}

(i)You can set this in the build settings tab or the summary tab. Start at the top left of the window in the Project Navigator, with all the files listed in it. Click the top-most one which has a blue icon.

(ii)If you are planning on using the programmable shader line circuitry, which is accessed and controlled through openGL ES 2.0 API, then you should set your "Deployment Version" to about 4.3, which I believe is only available on devices such as the 3GS or newer. xCode is reporting that iOS 4.2.5 or higher is needed run armv7 code. And once again, this processor, I believe, started with the 3GS.* iOS 4.3 seems to be the choice for me, for now.

How to make bootstrap column height to 100% row height?

You can solve that using display table.

Here is the updated JSFiddle that solves your problem.


.body {
    display: table;
    background-color: green;

.left-side {
    background-color: blue;
    float: none;
    display: table-cell;
    border: 1px solid;

.right-side {
    background-color: red;
    float: none;
    display: table-cell;
    border: 1px solid;


<div class="row body">
        <div class="col-xs-9 left-side">
        <div class="col-xs-3 right-side">

Append text to input field

You are probably looking for val()

From a Sybase Database, how I can get table description ( field names and types)?

If you want to use a command line program, but are not restricted to using SQL, you can use SchemaCrawler. SchemaCrawler is open source, and can produce files in plain text, CSV, or (X)HTML formats.

Freeze the top row for an html table only (Fixed Table Header Scrolling)

Using css zebra styling

Copy paste this example and see the header fixed.

       .zebra tr:nth-child(odd){

       .zebra tr:nth-child(even){
       background: grey;

      .zebra tr:nth-child(1) {
       position: fixed;
       margin:-30px 0px 0px 0px;

   <DIV  id= "stripped_div"

         class= "zebra"
         style = "
            border:solid 1px red;
            padding:30px 0px 0px 0px;"

                   <tr >
                    <tr >


Notice the top padding of of 30px in the div leaves space that is utilized by the 1st row of stripped data ie tr:nth-child(1) that is "fixed position" and formatted to a margin of -30px

Add column with constant value to pandas dataframe

Super simple in-place assignment: df['new'] = 0

For in-place modification, perform direct assignment. This assignment is broadcasted by pandas for each row.

df = pd.DataFrame('x', index=range(4), columns=list('ABC'))

   A  B  C
0  x  x  x
1  x  x  x
2  x  x  x
3  x  x  x

df['new'] = 'y'
# Same as,
# df.loc[:, 'new'] = 'y'

   A  B  C new
0  x  x  x   y
1  x  x  x   y
2  x  x  x   y
3  x  x  x   y

Note for object columns

If you want to add an column of empty lists, here is my advice:

  • Consider not doing this. object columns are bad news in terms of performance. Rethink how your data is structured.
  • Consider storing your data in a sparse data structure. More information: sparse data structures
  • If you must store a column of lists, ensure not to copy the same reference multiple times.

    # Wrong
    df['new'] = [[]] * len(df)
    # Right
    df['new'] = [[] for _ in range(len(df))]

Generating a copy: df.assign(new=0)

If you need a copy instead, use DataFrame.assign:


   A  B  C new
0  x  x  x   y
1  x  x  x   y
2  x  x  x   y
3  x  x  x   y

And, if you need to assign multiple such columns with the same value, this is as simple as,

c = ['new1', 'new2', ...]
df.assign(**dict.fromkeys(c, 'y'))

   A  B  C new1 new2
0  x  x  x    y    y
1  x  x  x    y    y
2  x  x  x    y    y
3  x  x  x    y    y

Multiple column assignment

Finally, if you need to assign multiple columns with different values, you can use assign with a dictionary.

c = {'new1': 'w', 'new2': 'y', 'new3': 'z'}

   A  B  C new1 new2 new3
0  x  x  x    w    y    z
1  x  x  x    w    y    z
2  x  x  x    w    y    z
3  x  x  x    w    y    z

Is it possible for UIStackView to scroll?

Horizontal Scrolling (UIStackView within UIScrollView)

For horizontal scrolling. First, create a UIStackView and a UIScrollView and add them to your view in the following way:

let scrollView = UIScrollView()
let stackView = UIStackView()


Remembering to set the translatesAutoresizingMaskIntoConstraints to false on the UIStackView and the UIScrollView:

stackView.translatesAutoresizingMaskIntoConstraints = false
scrollView.translatesAutoresizingMaskIntoConstraints = false

To get everything working the trailing, leading, top and bottom anchors of the UIStackView should be equal to the UIScrollView anchors:

stackView.leadingAnchor.constraint(equalTo: scrollView.leadingAnchor).isActive = true
stackView.trailingAnchor.constraint(equalTo: scrollView.trailingAnchor).isActive = true
stackView.topAnchor.constraint(equalTo: scrollView.topAnchor).isActive = true
stackView.bottomAnchor.constraint(equalTo: scrollView.bottomAnchor).isActive = true

But the width anchor of the UIStackView must the equal to or greater than the width of the UIScrollView anchor:

stackView.widthAnchor.constraint(greaterThanOrEqualTo: scrollView.widthAnchor).isActive = true

Now anchor your UIScrollView, for example:

scrollView.heightAnchor.constraint(equalToConstant: 80).isActive = true
scrollView.widthAnchor.constraint(equalTo: view.widthAnchor).isActive = true

scrollView.bottomAnchor.constraint(equalTo:view.safeAreaLayoutGuide.bottomAnchor).isActive = true
scrollView.leadingAnchor.constraint(equalTo:view.leadingAnchor).isActive = true
scrollView.trailingAnchor.constraint(equalTo:view.trailingAnchor).isActive = true 

Next, I would suggest trying the following settings for the UIStackView alignment and distribution:

topicStackView.axis = .horizontal
topicStackView.distribution = .equalCentering
topicStackView.alignment = .center

topicStackView.spacing = 10

Finally you'll need to use the addArrangedSubview: method to add subviews to your UIStackView.

Text Insets

One additional feature that you might find useful is that because the UIStackView is held within a UIScrollView you now have access to text insets to make things look a bit prettier.

let inset:CGFloat = 20
scrollView.contentInset.left = inset
scrollView.contentInset.right = inset

// remember if you're using insets then reduce the width of your stack view to match
stackView.widthAnchor.constraint(greaterThanOrEqualTo: topicScrollView.widthAnchor, constant: -inset*2).isActive = true

How do I add a .click() event to an image?

<!DOCTYPE html>
<script src=""></script> 
<script type="text/javascript" src="jquery-2.1.0.js"></script> 
<script type="text/javascript" >
function openOnImageClick()
//alert("Jai Sh Raam");
// document.getElementById("images").src = "fruits.jpg";
 var img = document.createElement('img');
 img.setAttribute('src', 'tiger.jpg');
  img.setAttribute('width', '200');
   img.setAttribute('height', '150');



<h1>Screen Shot View</h1>
<p>Click the Tiger to display the Image</p>

<div id="images" >

<img src="tiger.jpg" width="100" height="50" alt="unfinished bingo card" onclick="openOnImageClick()" />
<img src="Logo1.jpg" width="100" height="50" alt="unfinished bingo card" onclick="openOnImageClick()" />


Generate a random date between two other dates

Here is an answer to the literal meaning of the title rather than the body of this question:

import time
import datetime
import random

def date_to_timestamp(d) :
  return int(time.mktime(d.timetuple()))

def randomDate(start, end):
  """Get a random date between two dates"""

  stime = date_to_timestamp(start)
  etime = date_to_timestamp(end)

  ptime = stime + random.random() * (etime - stime)


This code is based loosely on the accepted answer.

Fit image into ImageView, keep aspect ratio and then resize ImageView to image dimensions?

this can all be done using XML... the other methods seem pretty complicated. Anyway, you just set the height to what ever you want in dp, then set the width to wrap content or visa versa. Use scaleType fitCenter to adjust the size of the image.


What is Node.js' Connect, Express and "middleware"?

middleware as the name suggests actually middleware is sit between middle.. middle of what? middle of request and request,response,express server sit in express app in this picture you can see requests are coming from client then the express server server serves those requests.. then lets dig deeper.. actually we can divide this whole express server's whole task in to small seperate tasks like in this way. how middleware sit between request and response small chunk of server parts doing some particular task and passed request to next one.. finally doing all the tasks response has been made.. all middle ware can access request object,response object and next function of request response cycle..

this is good example for explaining middleware in express youtube video for middleware

Presenting a UIAlertController properly on an iPad using iOS 8

It will work for both iphone and ipad

func showImagePicker() {
    var alertStyle = UIAlertController.Style.actionSheet
    if (UIDevice.current.userInterfaceIdiom == .pad) {
      alertStyle = UIAlertController.Style.alert
    let alert = UIAlertController(title: "", message: "Upload Attachment", preferredStyle: alertStyle)
    alert.addAction(UIAlertAction(title: "Choose from gallery", style: .default , handler:{ (UIAlertAction) in
        self.pickPhoto(sourceType: .photoLibrary)
    alert.addAction(UIAlertAction(title: "Take Photo", style: .default, handler:{ (UIAlertAction) in
        self.pickPhoto(sourceType: .camera)
    alert.addAction(UIAlertAction(title: "Cancel", style: .cancel, handler:{ (UIAlertAction) in
    present(alert, animated: true, completion: nil)

Spring JPA and persistence.xml

I'm confused. You're injecting a PU into the service layer and not the persistence layer? I don't get that.

I inject the persistence layer into the service layer. The service layer contains business logic and demarcates transaction boundaries. It can include more than one DAO in a transaction.

I don't get the magic in your save() method either. How is the data saved?

In production I configure spring like this:

<jee:jndi-lookup id="entityManagerFactory" jndi-name="persistence/ThePUname" />

along with the reference in web.xml

For unit testing I do this:

<bean id="entityManagerFactory"
    p:dataSource-ref="dataSource" p:persistence-xml-location="classpath*:META-INF/test-persistence.xml"
    p:persistence-unit-name="RealPUName" p:jpaDialect-ref="jpaDialect"
    p:jpaVendorAdapter-ref="jpaVendorAdapter" p:loadTimeWeaver-ref="weaver">

How to expire a cookie in 30 minutes using jQuery?

If you're using jQuery Cookie (, you can use decimal point or fractions.

As one day is 1, one minute would be 1 / 1440 (there's 1440 minutes in a day).

So 30 minutes is 30 / 1440 = 0.02083333.

Final code:

$.cookie("example", "foo", { expires: 30 / 1440, path: '/' });

I've added path: '/' so that you don't forget that the cookie is set on the current path. If you're on /my-directory/ the cookie is only set for this very directory.

Add day(s) to a Date object

date.setTime( date.getTime() + days * 86400000 );

CUSTOM_ELEMENTS_SCHEMA added to NgModule.schemas still showing Error

I'd like to add one additional piece of information since the accepted answer above didn't fix my errors completely.

In my scenario, I have a parent component, which holds a child component. And that child component also contains another component.

So, my parent component's spec file need to have the declaration of the child component, AS WELL AS THE CHILD'S CHILD COMPONENT. That finally fixed the issue for me.

How to programmatically determine the current checked out Git branch

That's one solution. If you add it to your .bashrc, it'll display the current branch in the console.

# git branch
parse_git_branch() {
    git branch 2> /dev/null | sed -e '/^[^*]/d' -e 's/* \(.*\)/(\1) /'

However it's pretty limited. But there is a great project called git sh, which is doing exactly that (and much more).

Custom edit view in UITableViewCell while swipe left. Objective-C or Swift

override func tableView(tableView: UITableView, editActionsForRowAtIndexPath indexPath: NSIndexPath) -> [UITableViewRowAction]? {
    let delete = UITableViewRowAction(style: .Destructive, title: "Delete") { (action, indexPath) in
        // delete item at indexPath

    let share = UITableViewRowAction(style: .Normal, title: "Disable") { (action, indexPath) in
    // share item at indexPath

    share.backgroundColor = UIColor.blueColor()

    return [delete, share]

The above code shows how to create to custom buttons when your swipe on the row.

PHP Unset Session Variable

// set
$_SESSION['test'] = 1;

// destroy

How to properly set Column Width upon creating Excel file? (Column properties)

See this snippet: (C#)

    private Microsoft.Office.Interop.Excel.Application xla;
    Workbook wb;
    Worksheet ws;
    Range rg;

        xla = new Microsoft.Office.Interop.Excel.Application();
        wb = xla.Workbooks.Add(XlSheetType.xlWorksheet);
        ws = (Worksheet)xla.ActiveSheet;
        rg = (Range)ws.Cells[1, 2];
        rg.ColumnWidth = 10;
        rg.Value2 = "Frequency";
        rg = (Range)ws.Cells[1, 3];
        rg.ColumnWidth = 15;
        rg.Value2 = "Impudence";
        rg = (Range)ws.Cells[1, 4];
        rg.ColumnWidth = 8;
        rg.Value2 = "Phase";

How to run a shell script at startup

Create your own /init executable

This is not what you want, but it is fun!

Just pick an arbitrary executable file, even a shell script, and boot the kernel with the command line parameter:


Towards the end of boot, the Linux kernel runs the first userspace executable at the given path.

Several projects provide popular init executables used by major distros, e.g. systemd, and in most distros init will fork a bunch of processes used in normal system operation.

But we can hijack /init it to run our own minimal scripts to better understand our system.

Here is a minimal reproducible setup:

Using SVG as background image

You can try removing the width and height attributes on the svg root element, adding preserveAspectRatio="none" viewBox="0 0 1024 800" instead. It makes a difference in Opera at least, assuming you wanted the svg to stretch to fill the entire region defined by the CSS styles.

XAMPP PORT 80 is Busy / EasyPHP error in Apache configuration file:

Just do one thing

open skype > tools > advance or advance settings Change port 80 to something else 7395

Restart your system then start Apache

How can I disable HREF if onclick is executed?

I solved a situation where I needed a template for the element that would handle alternatively a regular URL or a javascript call, where the js function needs a reference to the calling element. In javascript, "this" works as a self reference only in the context of a form element, e.g., a button. I didn't want a button, just the apperance of a regular link.


<a onclick="http://blahblah" href="http://blahblah" target="_blank">A regular link</a>
<a onclick="javascript:myFunc($(this));return false" href="javascript:myFunc($(this));"  target="_blank">javascript with self reference</a>

The href and onClick attributes have the same values, exept I append "return false" on onClick when it's a javascript call. Having "return false" in the called function did not work.

Remove item from list based on condition

If your collection type is a List<stuff>, then the best approach is probably the following:

prods.RemoveAll(s => s.ID == 1)

This only does one pass (iteration) over the list, so should be more efficient than other methods.

If your type is more generically an ICollection<T>, it might help to write a short extension method if you care about performance. If not, then you'd probably get away with using LINQ (calling Where or Single).

How to append to a file in Node?

Node.js 0.8 has fs.appendFile:

fs.appendFile('message.txt', 'data to append', (err) => {
  if (err) throw err;
  console.log('The "data to append" was appended to file!');


How to return a resolved promise from an AngularJS Service using $q?

How to simply return a pre-resolved promise in AngularJS

Resolved promise:

return $q.when( someValue );    // angularjs 1.2+
return $q.resolve( someValue ); // angularjs 1.4+, alias to `when` to match ES6

Rejected promise:

return $q.reject( someValue );

Base table or view not found: 1146 Table Laravel 5

Check your migration file, maybe you are using Schema::table, like this:

Schema::table('table_name', function ($table)  {
    // ...

If you want to create a new table you must use Schema::create:

Schema::create('table_name', function ($table)  {
    // ...

javascript createElement(), style problem

yourElement.setAttribute("style", "background-color:red; font-size:2em;");

Or you could write the element as pure HTML and use .innerHTML = [raw html code]... that's very ugly though.

In answer to your first question, first you use var myElement = createElement(...);, then you do document.body.appendChild(myElement);.

how to check if input field is empty

As javascript is dynamically typed, rather than using the .length property as above you can simply treat the input value as a boolean:

var input = $.trim($("#spa").val());

if (input) {
    // Do Stuff

You can also extract the logic out into functions, then by assigning a class and using the each() method the code is more dynamic if, for example, in the future you wanted to add another input you wouldn't need to change any code.

So rather than hard coding the function call into the input markup, you can give the inputs a class, in this example it's test, and use:

$(".test").each(function () {
    $(this).keyup(function () {
        $("#submit").prop("disabled", CheckInputs());

which would then call the following and return a boolean value to assign to the disabled property:

function CheckInputs() {
    var valid = false;
    $(".test").each(function () {
        if (valid) { return valid; }
        valid = !$.trim($(this).val());
    return valid;

You can see a working example of everything I've mentioned in this JSFiddle.

cannot find zip-align when publishing app

On a Mac, I did the following:

  1. Find it on o/s (I had already downloaded build tools for 19 and 20)

  2. Press Ctrl-Open to allow apps from the internet

  3. Move it from sdk/build-tools/android-4.4W folder to sdk/tools/. Whew.

How to iterate through an ArrayList of Objects of ArrayList of Objects?

int i = 0; // Counter used to determine when you're at the 3rd gun
for (Gun g : gunList) { // For each gun in your list
    System.out.println(g); // Print out the gun
    if (i == 2) { // If you're at the third gun
        ArrayList<Bullet> bullets = g.getBullet(); // Get the list of bullets in the gun
        for (Bullet b : bullets) { // Then print every bullet
    i++; // Don't forget to increment your counter so you know you're at the next gun

C# Convert a Base64 -> byte[]

You have to use Convert.FromBase64String to turn a Base64 encoded string into a byte[].

Why would anybody use C over C++?

There's also the approach some shops take of using some of C++'s features in a C-like way, but avoiding ones that are objectionable. For example, using classes and class methods and function overloading (which are usually easy for even C diehards to cope with), but not the STL, stream operators, and Boost (which are harder to learn and can have bad memory characteristics).

When to use Interface and Model in TypeScript / Angular

Use Class instead of Interface that is what I discovered after all my research.

Why? A class alone is less code than a class-plus-interface. (anyway you may require a Class for data model)

Why? A class can act as an interface (use implements instead of extends).

Why? An interface-class can be a provider lookup token in Angular dependency injection.

from Angular Style Guide

Basically a Class can do all, what an Interface will do. So may never need to use an Interface.

Passing parameters to JavaScript files

You use Global variables :-D.

Like this:

<script type="text/javascript">
   var obj1 = "somevalue";
   var obj2 = "someothervalue";
<script type="text/javascript" src="file.js"></script">

The JavaScript code in 'file.js' can access to obj1 and obj2 without problem.

EDIT Just want to add that if 'file.js' wants to check if obj1 and obj2 have even been declared you can use the following function.

function IsDefined($Name) {
    return (window[$Name] != undefined);

Hope this helps.

Remove element of a regular array

Here's how I did it...

    public static ElementDefinitionImpl[] RemoveElementDefAt(
        ElementDefinition[] oldList,
        int removeIndex
        ElementDefinitionImpl[] newElementDefList = new ElementDefinitionImpl[ oldList.Length - 1 ];

        int offset = 0;
        for ( int index = 0; index < oldList.Length; index++ )
            ElementDefinitionImpl elementDef = oldList[ index ] as ElementDefinitionImpl;
            if ( index == removeIndex )
                //  This is the one we want to remove, so we won't copy it.  But 
                //  every subsequent elementDef will by shifted down by one.
                offset = -1;
                newElementDefList[ index + offset ] = elementDef;
        return newElementDefList;

How do you add an ActionListener onto a JButton in Java

Your best bet is to review the Java Swing tutorials, specifically the tutorial on Buttons.

The short code snippet is:

jBtnDrawCircle.addActionListener( /*class that implements ActionListener*/ );

Insert multiple rows into single column

In that code you are inserting two column value. You can try this

   INSERT INTO Data ( Col1 ) VALUES ('Hello'),
   INSERT INTO Data ( Col1 ) VALUES ('World')

Camera access through browser

In iOS6, Apple supports this via the <input type="file"> tag. I couldn't find a useful link in Apple's developer documentation, but there's an example here.

It looks like overlays and more advanced functionality is not yet available, but this should work for a lot of use cases.

EDIT: The w3c has a spec that iOS6 Safari seems to implement a subset of. The capture attribute is notably missing.

Convert dictionary values into array

Store it in a list. It is easier;

List<Foo> arr = new List<Foo>(dict.Values);

Of course if you specifically want it in an array;

Foo[] arr = (new List<Foo>(dict.Values)).ToArray();

Finding and removing non ascii characters from an Oracle Varchar2

I had a similar issue and blogged about it here. I started with the regular expression for alpha numerics, then added in the few basic punctuation characters I liked:

select dump(a,1016), a, b
 (select regexp_replace(COLUMN,'[[:alnum:]/''%()> -.:=;[]','') a,
         COLUMN b
  from TABLE)
where a is not null
order by a;

I used dump with the 1016 variant to give out the hex characters I wanted to replace which I could then user in a utl_raw.cast_to_varchar2.

Perform Button click event when user press Enter key in Textbox

You can do it with javascript/jquery:

    function runScript(e) {
        if (e.keyCode == 13) {
            $("#myButton").click(); //jquery
            document.getElementById("myButton").click(); //javascript

<asp:textbox id="txtUsername" runat="server" onkeypress="return runScript(event)" />

<asp:LinkButton id="myButton" text="Login" runat="server" />

How to remove all white spaces in java


  string output = YourString.replaceAll("\\s","")

s - indicates space character (tab characters etc)

Difference between java HH:mm and hh:mm on SimpleDateFormat

h/H = 12/24 hours means you will write hh:mm = 12 hours format and HH:mm = 24 hours format

How do I change Eclipse to use spaces instead of tabs?

And don't forget the ANT editor

For some reason Ant Editor does not show up in the search results for 'tab' or 'spaces' so can be missed.

Under Windows > Preferences

  • Ant » Editor » Formatter » Tab size: (set to 4)
  • Ant » Editor » Formatter » Use tab character instead of spaces (uncheck it)

Is it possible to install another version of Python to Virtualenv?

The usual approach is to download the source and build and install locally (but not directly in virtualenv), and then create a new virtualenv using that local Python install. On some systems, it may be possible to download and install a prebuilt python, rather than building from source.

How to show progress bar while loading, using ajax

$(document).ready(function () { _x000D_
 $(document).ajaxStart(function () {_x000D_
    $(document).ajaxStop(function () {_x000D_
    $(document).ajaxError(function () {_x000D_
    });   _x000D_
<div id="wait" style="display: none; width: 100%; height: 100%; top: 100px; left: 0px; position: fixed; z-index: 10000; text-align: center;">_x000D_
            <img src="../images/loading_blue2.gif" width="45" height="45" alt="Loading..." style="position: fixed; top: 50%; left: 50%;" />_x000D_

Open files always in a new tab

Watch for filenames in italic

Note that, the file name on the tab is formatted in italic if it has been opened in Preview Mode.

Quickly take a file out of Preview Mode

To keep the file always available in VSCode editor (that is, to take it out of Preview Mode into normal mode), you can double-click on the tab. Then, you will notice the name becomes non-italic.

Feature or bug?

I believe Preview Mode is helpful especially when you have limited screen space and need to check many files.

Printing an int list in a single line python3

You have multiple options, each with different general use cases.

The first would be to use a for loop, as you described, but in the following way.

for value in array:
    print(value, end=' ')

You could also use str.join for a simple, readable one-liner using comprehension. This method would be good for storing this value to a variable.

print(' '.join(str(value) for value in array))

My favorite method, however, would be to pass array as *args, with a sep of ' '. Note, however, that this method will only produce a printed output, not a value that may be stored to a variable.

print(*array, sep=' ')

Angular 2 ngfor first, last, index loop

Check out this plunkr.

When you're binding to variables, you need to use the brackets. Also, you use the hashtag when you want to get references to elements in your html, not for declaring variables inside of templates like that.

<md-button-toggle *ngFor="let indicador of indicadores; let first = first;" [value]="" [checked]="first"> 

Edit: Thanks to Christopher Moore: Angular exposes the following local variables:

  • index
  • first
  • last
  • even
  • odd

numpy array TypeError: only integer scalar arrays can be converted to a scalar index

I ran into the problem when venturing to use numpy.concatenate to emulate a C++ like pushback for 2D-vectors; If A and B are two 2D numpy.arrays, then numpy.concatenate(A,B) yields the error.

The fix was to simply to add the missing brackets: numpy.concatenate( ( A,B ) ), which are required because the arrays to be concatenated constitute to a single argument

How to import an existing project from GitHub into Android Studio

You can directly import github projects into Android Studio. File -> New -> Project from Version Control -> GitHub. Then enter your github username and password.Select the repository and hit clone.

The github repo will be created as a new project in android studio.

Converting double to integer in Java

For the datatype Double to int, you can use the following:

Double double = 5.00;

int integer = double.intValue();

Creating lowpass filter in SciPy - understanding methods and units

A few comments:

  • The Nyquist frequency is half the sampling rate.
  • You are working with regularly sampled data, so you want a digital filter, not an analog filter. This means you should not use analog=True in the call to butter, and you should use scipy.signal.freqz (not freqs) to generate the frequency response.
  • One goal of those short utility functions is to allow you to leave all your frequencies expressed in Hz. You shouldn't have to convert to rad/sec. As long as you express your frequencies with consistent units, the scaling in the utility functions takes care of the normalization for you.

Here's my modified version of your script, followed by the plot that it generates.

import numpy as np
from scipy.signal import butter, lfilter, freqz
import matplotlib.pyplot as plt

def butter_lowpass(cutoff, fs, order=5):
    nyq = 0.5 * fs
    normal_cutoff = cutoff / nyq
    b, a = butter(order, normal_cutoff, btype='low', analog=False)
    return b, a

def butter_lowpass_filter(data, cutoff, fs, order=5):
    b, a = butter_lowpass(cutoff, fs, order=order)
    y = lfilter(b, a, data)
    return y

# Filter requirements.
order = 6
fs = 30.0       # sample rate, Hz
cutoff = 3.667  # desired cutoff frequency of the filter, Hz

# Get the filter coefficients so we can check its frequency response.
b, a = butter_lowpass(cutoff, fs, order)

# Plot the frequency response.
w, h = freqz(b, a, worN=8000)
plt.subplot(2, 1, 1)
plt.plot(0.5*fs*w/np.pi, np.abs(h), 'b')
plt.plot(cutoff, 0.5*np.sqrt(2), 'ko')
plt.axvline(cutoff, color='k')
plt.xlim(0, 0.5*fs)
plt.title("Lowpass Filter Frequency Response")
plt.xlabel('Frequency [Hz]')

# Demonstrate the use of the filter.
# First make some data to be filtered.
T = 5.0         # seconds
n = int(T * fs) # total number of samples
t = np.linspace(0, T, n, endpoint=False)
# "Noisy" data.  We want to recover the 1.2 Hz signal from this.
data = np.sin(1.2*2*np.pi*t) + 1.5*np.cos(9*2*np.pi*t) + 0.5*np.sin(12.0*2*np.pi*t)

# Filter the data, and plot both the original and filtered signals.
y = butter_lowpass_filter(data, cutoff, fs, order)

plt.subplot(2, 1, 2)
plt.plot(t, data, 'b-', label='data')
plt.plot(t, y, 'g-', linewidth=2, label='filtered data')
plt.xlabel('Time [sec]')


lowpass example

'No JUnit tests found' in Eclipse

I had the same problem and solved like this: I deleted @Test annotation and retyped it. It just worked, I have no idea why.

Cannot open include file: 'stdio.h' - Visual Studio Community 2017 - C++ Error

There are three ways to solve this issue.

  1. Ignore Precompiled Headers #1
    Steps: Project > Properties > Configuration Properties > C/C++ > Command Line > in the Additional Options box add /Y-. (Screenshot of Property Pages) > Ok > Remove #include "stdafx.h"
  2. Ignore Precompiled Headers #2
    Steps: File > New > Project > ... > In the Application Wizard Window click Next > Uncheck the Precompiled Header box > Finish > Remove #include "stdafx.h"
  3. Reinstall Visual Studio
    This also worked for me, because I realized that maybe there was something wrong with my Windows SDK. I was using Windows 10, but with Windows SDK 8.1. You may have this problem as well.
    Steps: Open Visual Studio Installer > Click on the three-lined Menu Bar > Uninstall > Restart your computer > Open Visual Studio Installer > Install what you want, but make sure you install only the latest Windows SDK 10, not multiple ones nor the 8.1.

    The first time I installed Visual Studio, I would get an error stating that I needed to install Windows SDK 8.1. So I did, through Visual Studio Installer's Modify option. Perhaps this was a problem because I was installed it after Visual Studio was already installed, or because I needed SDK 10 instead. Just to be safe I did a complete reinstall.

Execute PHP script in cron job

I had the same problem... I had to run it as a user.

00 * * * * root /usr/bin/php /var/virtual/

Can I call a constructor from another constructor (do constructor chaining) in C++?

Another option that has not been shown yet is to split your class into two, wrapping a lightweight interface class around your original class in order to achieve the effect you are looking for:

class Test_Base {
    public Test_Base() {

class Test : public Test_Base {
    public Test() : Test_Base() {

    public Test(int count) : Test_Base() {

This could get messy if you have many constructors that must call their "next level up" counterpart, but for a handful of constructors, it should be workable.

How to auto adjust the div size for all mobile / tablet display formats?

You question is a bit unclear as to what you want, but judging from your comments, I assume you want each bubble to cover the screen, both vertically and horizontally. In that case, the vertical part is the tricky part.

As many others have answered, you first need to make sure that you are setting the viewport meta tag to trigger mobile devices to use their "ideal" viewport instead of the emulated "desktop width" viewport. The easiest and most fool proof version of this tag is as follows:

<meta name="viewport" content="width=device-width, initial-scale=1">

Source: PPK, probably the leading expert on how this stuff works. (See

Essentially, the above makes sure that media queries and CSS measurements correspond to the ideal display of a virtual "point" on any given device — instead of shrinking pages to work with non-optimized desktop layouts. You don't need to understand the details of it, but it's important.

Now that we have a correct (non-faked) mobile viewport to work with, adjusting to the height of the viewport is still a tricky subject. Generally, web pages are fine to expand vertically, but not horizontally. So when you set height: 100% on something, that measurement has to relate to something else. At the topmost level, this is the size of the HTML element. But when the HTML element is taller than the screen (and expands to contain the contents), your measurements in percentages will be screwed up.

Enter the vh unit: it works like percentages, but works in relation to the viewport, not the containing block. MDN info page here:

Using that unit works just like you'd expect:

.bubble { height: 100vh; } /* be as tall as the viewport height. Done. */

It works on a lot of browsers (IE9 and up, modern Firefox, Safari, Chrome, Opera etc) but not all (support info here: The downside in the browsers where it does work is that there is a massive bug in iOS6-7 that makes this technique unusable for this very case (details here: It will be fixed in iOS8 though.

Depending on the HTML structure of your project, you may get away with using height: 100% on each element that is supposed to be as tall as the screen, as long as the following conditions are met:

  1. The element is a direct child element of <body>.
  2. Both the html and body elements have a 100% height set.

I have used that technique in the past, but it was long ago and I'm not sure it works on most mobile devices. Try it and see.

The next choice is to use a JavaScript helper to resize your elements to fit the viewport. Either a polyfill fixing the vh issues or something else altogether. Sadly, not every layout is doable in CSS.

convert NSDictionary to NSString

You can call [aDictionary description], or anywhere you would need a format string, just use %@ to stand in for the dictionary:

[NSString stringWithFormat:@"my dictionary is %@", aDictionary];


NSLog(@"My dictionary is %@", aDictionary);

Use JavaScript to place cursor at end of text in text input element

If you set the value first and then set the focus, the cursor will always appear at the end.

$("#search-button").click(function (event) {
    return false;

Here is the fiddle to test

How can I use MS Visual Studio for Android Development?

Much has changed since this question was asked. Visual Studio 2013 with update 4 and Visual Studio 2015 now have integrated tools for Apache Cordova and you can run them on a Visual Studio emulator for Android.

How to enable CORS in flask

My solution is a wrapper around app.route:

def corsapp_route(path, origin=('',), **options):
    Flask app alias with cors

    def inner(func):
        def wrapper(*args, **kwargs):
            if request.method == 'OPTIONS':
                response = make_response()
                response.headers.add("Access-Control-Allow-Origin", ', '.join(origin))
                response.headers.add('Access-Control-Allow-Headers', ', '.join(origin))
                response.headers.add('Access-Control-Allow-Methods', ', '.join(origin))
                return response
                result = func(*args, **kwargs)
            if 'Access-Control-Allow-Origin' not in result.headers:
                result.headers.add("Access-Control-Allow-Origin", ', '.join(origin))
            return result

        wrapper.__name__ = func.__name__

        if 'methods' in options:
            if 'OPTIONS' in options['methods']:
                return app.route(path, **options)(wrapper)
                return app.route(path, **options)(wrapper)

        return wrapper

    return inner

@corsapp_route('/', methods=['POST'], origin=['*'])
def hello_world():

HTML anchor tag with Javascript onclick event

If your onclick function returns false the default browser behaviour is cancelled. As such:

<a href='' onclick='return check()'>check</a>

<script type='text/javascript'>

function check()
    return false;


Either way, whether google does it or not isn't of much importance. It's cleaner to bind your onclick functions within javascript - this way you separate your HTML from other code.

Why an interface can not implement another interface?

implements means implementation, when interface is meant to declare just to provide interface not for implementation.

A 100% abstract class is functionally equivalent to an interface but it can also have implementation if you wish (in this case it won't remain 100% abstract), so from the JVM's perspective they are different things.

Also the member variable in a 100% abstract class can have any access qualifier, where in an interface they are implicitly public static final.

make arrayList.toArray() return more specific types

 public static <E> E[] arrayListToTypedArray(List<E> list) {

    if (list == null) {
      return null;
    int noItems = list.size();
    if (noItems == 0) {
      return null;

    E[] listAsTypedArray;
    E typeHelper = list.get(0);

    try {
      Object o = Array.newInstance(typeHelper.getClass(), noItems);
      listAsTypedArray = (E[]) o;
      for (int i = 0; i < noItems; i++) {
        Array.set(listAsTypedArray, i, list.get(i));
    } catch (Exception e) {
      return null;

    return listAsTypedArray;

How do I convert from int to String?

There are various ways of converting to Strings:

StringBuilder string = string.append(i).toString();
String string = String.valueOf(i);
String string = Integer.toString(i);

How do you share code between projects/solutions in Visual Studio?

One simpler way to include a class file of one project in another projects is by Adding the project in existing solution and then Adding the DLL reference of the new project in the existing project. Finally, you can use the methods of the added class by decalring using directive at the top of the any class.

SQL Server - Return value after INSERT

There are many ways to exit after insert

When you insert data into a table, you can use the OUTPUT clause to return a copy of the data that’s been inserted into the table. The OUTPUT clause takes two basic forms: OUTPUT and OUTPUT INTO. Use the OUTPUT form if you want to return the data to the calling application. Use the OUTPUT INTO form if you want to return the data to a table or a table variable.



IDENT_CURRENT: It returns the last identity created for a particular table or view in any session.


SCOPE_IDENTITY: It returns the last identity from a same session and the same scope. A scope is a stored procedure/trigger etc.


@@IDENTITY: It returns the last identity from the same session.


Difference between 2 dates in SQLite

 SELECT julianday('now') - julianday(DateCreated) FROM Payment;

switch() statement usage

In short, yes. But there are times when you might favor one vs. the other. Google "case switch vs. if else". There are some discussions already on SO too. Also, here is a good video that talks about it in the context of MATLAB:

Personally, when I have 3 or more cases, I usually just go with case/switch.

Better way to find last used row

This function should do the trick if you want to specify a particular sheet. I took the solution from user6432984 and modified it to not throw any errors. I am using Excel 2016 so it may not work for older versions:

Function findLastRow(ByVal inputSheet As Worksheet) As Integer
    findLastRow = inputSheet.cellS(inputSheet.Rows.Count, 1).End(xlUp).Row
End Function

This is the code to run if you are already working in the sheet you want to find the last row of:

Dim lastRow as Integer
lastRow = cellS(Rows.Count, 1).End(xlUp).Row

jQuery onclick event for <li> tags

I'm not really sure what your question is, but to get the text of the li element you can use:


And to get the id of an element you can use .attr('id');. Once you have a reference to the element you want (e.g. $(this)) you can perform any jQuery function on it.

Catching multiple exception types in one catch block

This article covers the question Content of the post copied directly from the article:

Example exceptions

Here's some example exceptions that have been defined for the purposes of this example:

class FooException extends Exception 
  public function __construct($message = null, $code = 0) 
    // do something

class BarException extends Exception 
  public function __construct($message = null, $code = 0) 
    // do something

class BazException extends Exception 
  public function __construct($message = null, $code = 0) 
    // do something

Handling multiple exceptions

It's very simple - there can be a catch block for each exception type that can be thrown:

  // some code that might trigger a Foo/Bar/Baz/Exception

catch(FooException $e) 
  // we caught a foo exception

catch(BarException $e) 
  // we caught a bar exception

catch(BazException $e) 
  // we caught a baz exception

catch(Exception $e) 
  // we caught a normal exception
  // or an exception that wasn't handled by any of the above

If an exception is thrown that is not handled by any of the other catch statements it will be handled by the catch(Exception $e) block. It does not necessarily have to be the last one.

Cannot read property length of undefined

perhaps, you can first determine if the DOM does really exists,

function walkmydog() {
    //when the user starts entering
    var dom = document.getElementById('WallSearch');
    if(dom == null){
        alert('sorry, WallSearch DOM cannot be found');
        return false;    

    if(dom.value.length == 0){

if (document.addEventListener){
    document.addEventListener("DOMContentLoaded", walkmydog, false);

entity object cannot be referenced by multiple instances of IEntityChangeTracker. while adding related objects to entity in Entity Framework 4.1

This is how I encountered this issue. First I need to save my Order which needs a reference to my ApplicationUser table:

  ApplicationUser user = new ApplicationUser();
  user = UserManager.FindById(User.Identity.GetUserId());

  Order entOrder = new Order();
  entOrder.ApplicationUser = user; //I need this user before saving to my database using EF

The problem is that I am initializing a new ApplicationDbContext to save my new Order entity:

 ApplicationDbContext db = new ApplicationDbContext();
 db.Entry(entOrder).State = EntityState.Added;

So in order to solve the problem, I used the same ApplicationDbContext instead of using the built-in UserManager of ASP.NET MVC.

Instead of this:

user = UserManager.FindById(User.Identity.GetUserId());

I used my existing ApplicationDbContext instance:

//db instance here is the same instance as my db on my code above.
user = db.Users.Find(User.Identity.GetUserId()); 

What is the difference between __init__ and __call__?

__init__ would be treated as Constructor where as __call__ methods can be called with objects any number of times. Both __init__ and __call__ functions do take default arguments.

Nginx: stat() failed (13: permission denied)

By default the static data, when you install the nginx, will be in /var/www/html. So you can just copy your static folder into /var/html/ and set the

root /var/www/<your static folder>

in ngix.conf (or /etc/nginx/sites-available/default)

This worked for me on ubuntu but I guess it should not be much different for other distros.

Hope it helps.

unix sort descending order

To list files based on size in asending order.

find ./ -size +1000M -exec ls -tlrh {} \; |awk -F" " '{print $5,$9}'  | sort -n\

Can't append <script> element

Another way you can do it if you want to append code is using the document.createElement method but then using .innerHTML instead of .src.

var script = document.createElement( 'script' );
script.type = 'text/javascript';
script.innerHTML = 'alert("Hey there... you just appended this script to the body");';
$("body").append( script );

Serving favicon.ico in ASP.NET MVC

Placing favicon.ico in the root of your domain only really affects IE5, IIRC. For more modern browsers you should be able to include a link tag to point to another directory:

<link rel="SHORTCUT ICON" href=""/>

You can also use non-ico files for browsers other than IE, for which I'd maybe use the following conditional statement to serve a PNG to FF,etc, and an ICO to IE:

<link rel="icon" type="image/png" href="" />
<!--[if IE]>
<link rel="shortcut icon" href="" type="image/" />

How to grey out a button?

All given answers work fine, but I remember learning that using setAlpha can be a bad idea performance wise (more info here). So creating a StateListDrawable is a better idea to manage disabled state of buttons. Here's how:

Create a XML btn_blue.xml in res/drawable folder:

<selector xmlns:android="">
    <!-- Disable background -->
    <item android:state_enabled="false"
    <!-- Enabled background -->
    <item android:color="@color/md_blue_500"/>

Create a button style in res/values/styles.xml

<style name="BlueButton" parent="ThemeOverlay.AppCompat">
      <item name="colorButtonNormal">@drawable/btn_blue</item>
      <item name="android:textColor">@color/md_white_1000</item>

Then apply this style to your button:


Now when you call btnBlue.setEnabled(true) OR btnBlue.setEnabled(false) the state colors will automatically switch.

How can one use multi threading in PHP applications

Multi-threading is possible in php

Yes you can do multi-threading in PHP with pthreads

From the PHP documentation:

pthreads is an object-orientated API that provides all of the tools needed for multi-threading in PHP. PHP applications can create, read, write, execute and synchronize with Threads, Workers and Threaded objects.

Warning: The pthreads extension cannot be used in a web server environment. Threading in PHP should therefore remain to CLI-based applications only.

Simple Test

class AsyncOperation extends Thread {

    public function __construct($arg) {
        $this->arg = $arg;

    public function run() {
        if ($this->arg) {
            $sleep = mt_rand(1, 10);
            printf('%s: %s  -start -sleeps %d' . "\n", date("g:i:sa"), $this->arg, $sleep);
            printf('%s: %s  -finish' . "\n", date("g:i:sa"), $this->arg);

// Create a array
$stack = array();

//Initiate Multiple Thread
foreach ( range("A", "D") as $i ) {
    $stack[] = new AsyncOperation($i);

// Start The Threads
foreach ( $stack as $t ) {


First Run

12:00:06pm:     A  -start -sleeps 5
12:00:06pm:     B  -start -sleeps 3
12:00:06pm:     C  -start -sleeps 10
12:00:06pm:     D  -start -sleeps 2
12:00:08pm:     D  -finish
12:00:09pm:     B  -finish
12:00:11pm:     A  -finish
12:00:16pm:     C  -finish

Second Run

12:01:36pm:     A  -start -sleeps 6
12:01:36pm:     B  -start -sleeps 1
12:01:36pm:     C  -start -sleeps 2
12:01:36pm:     D  -start -sleeps 1
12:01:37pm:     B  -finish
12:01:37pm:     D  -finish
12:01:38pm:     C  -finish
12:01:42pm:     A  -finish

Real World Example

class AsyncWebRequest extends Thread {
    public $url;
    public $data;

    public function __construct($url) {
        $this->url = $url;

    public function run() {
        if (($url = $this->url)) {
             * If a large amount of data is being requested, you might want to
             * fsockopen and read using usleep in between reads
            $this->data = file_get_contents($url);
        } else
            printf("Thread #%lu was not provided a URL\n", $this->getThreadId());

$t = microtime(true);
$g = new AsyncWebRequest(sprintf("", rand() * 10));
/* starting synchronization */
if ($g->start()) {
    printf("Request took %f seconds to start ", microtime(true) - $t);
    while ( $g->isRunning() ) {
        echo ".";
    if ($g->join()) {
        printf(" and %f seconds to finish receiving %d bytes\n", microtime(true) - $t, strlen($g->data));
    } else
        printf(" and %f seconds to finish, request failed\n", microtime(true) - $t);

Is it possible to open a Windows Explorer window from PowerShell?

start explorer.exe 

Simple single line command

JavaScript: What are .extend and .prototype used for?

Javascript's inheritance is prototype based, so you extend the prototypes of objects such as Date, Math, and even your own custom ones. = function() {

( new Date ).lol() // alert message

In the snippet above, I define a method for all Date objects ( already existing ones and all new ones ).

extend is usually a high level function that copies the prototype of a new subclass that you want to extend from the base class.

So you can do something like:

extend( Fighter, Human )

And the Fighter constructor/object will inherit the prototype of Human, so if you define methods such as live and die on Human then Fighter will also inherit those.

Updated Clarification:

"high level function" meaning .extend isn't built-in but often provided by a library such as jQuery or Prototype.

How to uninstall a package installed with pip install --user

Having tested this using Python 3.5 and pip 7.1.2 on Linux, the situation appears to be this:

  • pip install --user somepackage installs to $HOME/.local, and uninstalling it does work using pip uninstall somepackage.

  • This is true whether or not somepackage is also installed system-wide at the same time.

  • If the package is installed at both places, only the local one will be uninstalled. To uninstall the package system-wide using pip, first uninstall it locally, then run the same uninstall command again, with root privileges.

  • In addition to the predefined user install directory, pip install --target somedir somepackage will install the package into somedir. There is no way to uninstall a package from such a place using pip. (But there is a somewhat old unmerged pull request on Github that implements pip uninstall --target.)

  • Since the only places pip will ever uninstall from are system-wide and predefined user-local, you need to run pip uninstall as the respective user to uninstall from a given user's local install directory.

get current url in twig template?

{{ path(app.request.attributes.get('_route'),
     app.request.attributes.get('_route_params')) }}

If you want to read it into a view variable:

{% set currentPath = path(app.request.attributes.get('_route'),
                       app.request.attributes.get('_route_params')) %}

The app global view variable contains all sorts of useful shortcuts, such as app.session and, that reference the services you might use in a controller.

How to sum up an array of integers in C#

Using foreach would be shorter code, but probably do exactly the same steps at runtime after JIT optimization recognizes the comparison to Length in the for-loop controlling expression.

How to convert a Scikit-learn dataset to a Pandas dataset?

This snippet is only syntactic sugar built upon what TomDLT and rolyat have already contributed and explained. The only differences would be that load_iris will return a tuple instead of a dictionary and the columns names are enumerated.

df = pd.DataFrame(np.c_[load_iris(return_X_y=True)])

How to label scatterplot points by name?

Well I did not think this was possible until I went and checked. In some previous version of Excel I could not do this. I am currently using Excel 2013.

This is what you want to do in a scatter plot:

  1. right click on your data point

  2. select "Format Data Labels" (note you may have to add data labels first)

  3. put a check mark in "Values from Cells"
  4. click on "select range" and select your range of labels you want on the points

Example Graph

UPDATE: Colouring Individual Labels

In order to colour the labels individually use the following steps:

  1. select a label. When you first select, all labels for the series should get a box around them like the graph above.
  2. Select the individual label you are interested in editing. Only the label you have selected should have a box around it like the graph below.
  3. On the right hand side, as shown below, Select "TEXT OPTIONS".
  4. Expand the "TEXT FILL" category if required.
  5. Second from the bottom of the category list is "COLOR", select the colour you want from the pallet.

If you have the entire series selected instead of the individual label, text formatting changes should apply to all labels instead of just one.


How to increase the gap between text and underlining in CSS

No, but you could go with something like border-bottom: 1px solid #000 and padding-bottom: 3px.

If you want the same color of the "underline" (which in my example is a border), you just leave out the color declaration, i.e. border-bottom-width: 1px and border-bottom-style: solid.

For multiline, you can wrap you multiline texts in a span inside the element. E.g. <a href="#"><span>insert multiline texts here</span></a> then just add border-bottom and padding on the <span> - Demo

The action or event has been blocked by Disabled Mode

From access help:

Stop Disabled Mode from blocking a query If you try to run an append query and it seems like nothing happens, check the Access status bar for the following message:

This action or event has been blocked by Disabled Mode.

To stop Disabled Mode from blocking the query, you must enable the database content. You use the Options button in the Message Bar to enable the query.

Enable the append query In the Message Bar, click Options. In the Microsoft Office Security Options dialog box, click Enable this content, and then click OK. If you don't see the Message Bar, it may be hidden. You can show it, unless it has also been disabled. If the Message Bar has been disabled, you can enable it.

Show the Message Bar If the Message Bar is already visible, you can skip this step.

On the Database Tools tab, in the Show/Hide group, select the Message Bar check box. If the Message Bar check box is disabled, you will have to enable it.

Enable the Message Bar If the Message Bar check box is enabled, you can skip this step.

Click the Microsoft Office Button , and then click Access Options. In the left pane of the Access Options dialog box, click Trust Center. In the right pane, under Microsoft Office Access Trust Center, click Trust Center Settings. In the left pane of the Trust Center dialog box, click Message Bar. In the right pane, click Show the Message Bar in all applications when content has been blocked, and then click OK. Close and reopen the database to apply the changed setting. Note When you enable the append query, you also enable all other database content.

For more information about Access security, see the article Help secure an Access 2007 database.

Calculate RSA key fingerprint

To check a remote SSH server prior to the first connection, you can give a look at to see all SHH keys for the server, as well as from when the key is known.

That's not like an SSL certificate, but definitely a must-do before connecting to any SSH server for the first time.

Can promises have multiple arguments to onFulfilled?

To quote the article below, ""then" takes two arguments, a callback for a success case, and another for the failure case. Both are optional, so you can add a callback for the success or failure case only."

I usually look to this page for any basic promise questions, let me know if I am wrong

telnet to port 8089 correct command

I believe telnet 8089 . Why don't u try both

Correct way to pass multiple values for same parameter name in GET request

Indeed, there is no defined standard. To support that information, have a look at wikipedia, in the Query String chapter. There is the following comment:

While there is no definitive standard, most web frameworks allow multiple values to be associated with a single field.[3][4]

Furthermore, when you take a look at the RFC 3986, in section 3.4 Query, there is no definition for parameters with multiple values.

Most applications use the first option you have shown: http://server/action?id=a&id=b. To support that information, take a look at this Stackoverflow link, and this MSDN link regarding ASP.NET applications, which use the same standard for parameters with multiple values.

However, since you are developing the APIs, I suggest you to do what is the easiest for you, since the caller of the API will not have much trouble creating the query string.

How to secure the ASP.NET_SessionId cookie?

Here is a code snippet taken from a blog article written by Anubhav Goyal:

// this code will mark the forms authentication cookie and the
// session cookie as Secure.
if (Response.Cookies.Count > 0)
    foreach (string s in Response.Cookies.AllKeys)
        if (s == FormsAuthentication.FormsCookieName || "asp.net_sessionid".Equals(s, StringComparison.InvariantCultureIgnoreCase))
             Response.Cookies[s].Secure = true;

Adding this to the EndRequest event handler in the global.asax should make this happen for all page calls.

Note: An edit was proposed to add a break; statement inside a successful "secure" assignment. I've rejected this edit based on the idea that it would only allow 1 of the cookies to be forced to secure and the second would be ignored. It is not inconceivable to add a counter or some other metric to determine that both have been secured and to break at that point.

How to create CSV Excel file C#?

I added ExportToStream so the csv didn't have to save to the hard drive first.

public Stream ExportToStream()
    MemoryStream stream = new MemoryStream();
    StreamWriter writer = new StreamWriter(stream);
    stream.Position = 0;
    return stream;

Java - Using Accessor and Mutator methods

You need to remove the static from your accessor methods - these methods need to be instance methods and access the instance variables

public class IDCard {
    public String name, fileName;
    public int id;

    public IDCard(final String name, final String fileName, final int id) { = name;
        this.fileName = fileName = id;

    public String getName() {
        return name;

You can the create an IDCard and use the accessor like this:

final IDCard card = new IDCard();

Each time you call new a new instance of the IDCard will be created and it will have it's own copies of the 3 variables.

If you use the static keyword then those variables are common across every instance of IDCard.

A couple of things to bear in mind:

  1. don't add useless comments - they add code clutter and nothing else.
  2. conform to naming conventions, use lower case of variable names - name not Name.

Running unittest with typical test directory structure

Python 3+

Adding to @Pierre

Using unittest directory structure like this:

+-- antigravity
¦   +--         # make it a package
¦   +--
+-- test
    +--         # also make test a package

To run the test module

$ cd new_project
$ python -m unittest test.test_antigravity

Or a single TestCase

$ python -m unittest test.test_antigravity.GravityTestCase

Mandatory don't forget the even if empty otherwise will not work.

How to use random in BATCH script?

You'll probably want to get several random numbers, and may want to be able to specify a different range for each one, so you should define a function. In my example, I generate numbers from 25 through 30 with call:rand 25 30. And the result is in RAND_NUM after that function exits.

@echo off & setlocal EnableDelayedExpansion

for /L %%a in (1 1 10) do (
        call:rand 25 30
        echo !RAND_NUM!


REM The script ends at the above goto:EOF.  The following are functions.

REM rand()
REM Input: %1 is min, %2 is max.
REM Output: RAND_NUM is set to a random number from min through max.
SET /A RAND_NUM=%RANDOM% * (%2 - %1 + 1) / 32768 + %1

How to replace negative numbers in Pandas Data Frame by zero

If all your columns are numeric, you can use boolean indexing:

In [1]: import pandas as pd

In [2]: df = pd.DataFrame({'a': [0, -1, 2], 'b': [-3, 2, 1]})

In [3]: df
   a  b
0  0 -3
1 -1  2
2  2  1

In [4]: df[df < 0] = 0

In [5]: df
   a  b
0  0  0
1  0  2
2  2  1

For the more general case, this answer shows the private method _get_numeric_data:

In [1]: import pandas as pd

In [2]: df = pd.DataFrame({'a': [0, -1, 2], 'b': [-3, 2, 1],
                           'c': ['foo', 'goo', 'bar']})

In [3]: df
   a  b    c
0  0 -3  foo
1 -1  2  goo
2  2  1  bar

In [4]: num = df._get_numeric_data()

In [5]: num[num < 0] = 0

In [6]: df
   a  b    c
0  0  0  foo
1  0  2  goo
2  2  1  bar

With timedelta type, boolean indexing seems to work on separate columns, but not on the whole dataframe. So you can do:

In [1]: import pandas as pd

In [2]: df = pd.DataFrame({'a': pd.to_timedelta([0, -1, 2], 'd'),
   ...:                    'b': pd.to_timedelta([-3, 2, 1], 'd')})

In [3]: df
        a       b
0  0 days -3 days
1 -1 days  2 days
2  2 days  1 days

In [4]: for k, v in df.iteritems():
   ...:     v[v < 0] = 0

In [5]: df
       a      b
0 0 days 0 days
1 0 days 2 days
2 2 days 1 days

Update: comparison with a pd.Timedelta works on the whole DataFrame:

In [1]: import pandas as pd

In [2]: df = pd.DataFrame({'a': pd.to_timedelta([0, -1, 2], 'd'),
   ...:                    'b': pd.to_timedelta([-3, 2, 1], 'd')})

In [3]: df[df < pd.Timedelta(0)] = 0

In [4]: df
       a      b
0 0 days 0 days
1 0 days 2 days
2 2 days 1 days

How to convert JSON string to array

$data = json_encode($result, true);

echo $data;

What is two way binding?

Worth mentioning that there are many different solutions which offer two way binding and play really nicely.

I have had a pleasant experience with this model binder - which gives sensible defaults yet a lot of custom jquery selector mapping of model attributes to input elements.

There is a more extended list of backbone extensions/plugins on github

What's the difference between display:inline-flex and display:flex?

flex and inline-flex both apply flex layout to children of the container. Container with display:flex behaves like a block-level element itself, while display:inline-flex makes the container behaves like an inline element.

How to use MD5 in javascript to transmit a password

I would suggest you to use CryptoJS in this case.

Basically CryptoJS is a growing collection of standard and secure cryptographic algorithms implemented in JavaScript using best practices and patterns. They are fast, and they have a consistent and simple interface.

So In case you want calculate hash(MD5) of your password string then do as follows :

<script src=""></script>
    var passhash = CryptoJS.MD5(password).toString();

      { user: username, pass: passhash },
      'json' );

So this script will post hash of your password string to the server.

For further info and support on other hash calculating algorithms you can visit at:

Stretch background image css?

I think what you are looking for is

.style1 {
  background: url('http://localhost/msite/images/12.PNG');
  background-repeat: no-repeat;
  background-position: center;
  -webkit-background-size: contain;
  -moz-background-size: contain;
  -o-background-size: contain;
  background-size: contain;

How to install latest version of openssl Mac OS X El Capitan

To replace the old version with the new one, you need to change the link for it. Type that command to terminal.

brew link --force openssl

Check the version of openssl again. It should be changed.

Why does MSBuild look in C:\ for Microsoft.Cpp.Default.props instead of c:\Program Files (x86)\MSBuild? ( error MSB4019)

The registry entries for MSBuild key worked fine to me. It's important to remember that it must be done for 64-bit or 32-bit branches depending on which version of MSBuild you run. I wouldn't recommend to use environment variables as it may cause problems in different versions of MSBuild.

This registry file fixes that for both cases:

Windows Registry Editor Version 5.00











Contain an image within a div?

  <div id ="container">
    <img src = ""/>
#container img {
        width: 250px;
        height: 250px;
        border:1px solid #000;

The img will lose aspect ratio

Deleting Elements in an Array if Element is a Certain value VBA

here is a sample of code using the CopyMemory function to do the job.

It is supposedly "much faster" (depending of the size and type of the array...).

i am not the author, but i tested it :

Sub RemoveArrayElement_Str(ByRef AryVar() As String, ByVal RemoveWhich As Long) 

'// The size of the array elements
'// In the case of string arrays, they are
'// simply 32 bit pointers to BSTR's.
Dim byteLen As Byte

'// String pointers are 4 bytes
byteLen = 4

'// The copymemory operation is not necessary unless
'// we are working with an array element that is not
'// at the end of the array
If RemoveWhich < UBound(AryVar) Then
    '// Copy the block of string pointers starting at
    ' the position after the
    '// removed item back one spot.
    CopyMemory ByVal VarPtr(AryVar(RemoveWhich)), ByVal _
        VarPtr(AryVar(RemoveWhich + 1)), (byteLen) * _
        (UBound(AryVar) - RemoveWhich)
End If

'// If we are removing the last array element
'// just deinitialize the array
'// otherwise chop the array down by one.
If UBound(AryVar) = LBound(AryVar) Then
    Erase AryVar
    ReDim Preserve AryVar(LBound(AryVar) To UBound(AryVar) - 1)
End If
End Sub

top -c command in linux to filter processes listed based on processname

It can be done interactively

After running top -c , hit o and write a filter on a column, e.g. to show rows where COMMAND column contains the string foo, write COMMAND=foo

If you just want some basic output this might be enough:

top -bc |grep name_of_process

Adding up BigDecimals using Streams

This post already has a checked answer, but the answer doesn't filter for null values. The correct answer should prevent null values by using the Object::nonNull function as a predicate.

BigDecimal result =
    .filter(i -> (i.getUnit_price() != null) && (i.getQuantity != null))
    .reduce(BigDecimal.ZERO, BigDecimal::add);

This prevents null values from attempting to be summed as we reduce.

Proper way to concatenate variable strings

Since strings are lists of characters in Python, we can concatenate strings the same way we concatenate lists (with the + sign):

{{ var1 + '-' + var2 + '-' + var3 }}

If you want to pipe the resulting string to some filter, make sure you enclose the bits in parentheses:

e.g. To concatenate our 3 vars, and get a sha512 hash:

{{ (var1 + var2 + var3) | hash('sha512') }}

Note: this works on Ansible 2.3. I haven't tested it on earlier versions.

What is the best practice for creating a favicon on a web site?

  1. you can work with this website for generate favin.ico
  2. I recommend use .ico format because the png don't work with method 1 and ico could have more detail!
  3. both method work with all browser but when it's automatically work what you want type a code for it? so i think method 1 is better.

How to get certain commit from GitHub project

Sivan's answer in gif enter image description here

1.Click on commits in github

2.Select Browse code on the right side of each commit

3.Click on download zip , which will download source code at that point of time of commit

Why aren't python nested functions called closures?

Python has a weak support for closure. To see what I mean take the following example of a counter using closure with JavaScript:

function initCounter(){
    var x = 0;
    function counter  () {
        x += 1;
    return counter;

count = initCounter();

count(); //Prints 1
count(); //Prints 2
count(); //Prints 3

Closure is quite elegant since it gives functions written like this the ability to have "internal memory". As of Python 2.7 this is not possible. If you try

def initCounter():
    x = 0;
    def counter ():
        x += 1 ##Error, x not defined
        print x
    return counter

count = initCounter();

count(); ##Error

You'll get an error saying that x is not defined. But how can that be if it has been shown by others that you can print it? This is because of how Python it manages the functions variable scope. While the inner function can read the outer function's variables, it cannot write them.

This is a shame really. But with just read-only closure you can at least implement the function decorator pattern for which Python offers syntactic sugar.


As its been pointed out, there are ways to deal with python's scope limitations and I'll expose some.

1. Use the global keyword (in general not recommended).

2. In Python 3.x, use the nonlocal keyword (suggested by @unutbu and @leewz)

3. Define a simple modifiable class Object

class Object(object):

and create an Object scope within initCounter to store the variables

def initCounter ():
    scope = Object()
    scope.x = 0
    def counter():
        scope.x += 1
        print scope.x

    return counter

Since scope is really just a reference, actions taken with its fields do not really modify scope itself, so no error arises.

4. An alternative way, as @unutbu pointed out, would be to define each variable as an array (x = [0]) and modify it's first element (x[0] += 1). Again no error arises because x itself is not modified.

5. As suggested by @raxacoricofallapatorius, you could make x a property of counter

def initCounter ():

    def counter():
        counter.x += 1
        print counter.x

    counter.x = 0
    return counter

Remove all HTMLtags in a string (with the jquery text() function)

I created this test case: , I used the Javascript replace function with regular expressions to get the results that you want.

$(document).ready(function() {
    var myContent = '<div id="test">Hello <span>world!</span></div>';

How to remove non UTF-8 characters from text file

Your method must read byte by byte and fully understand and appreciate the byte wise construction of characters. The simplest method is to use an editor which will read anything but only output UTF-8 characters. Textpad is one choice.

How to increase request timeout in IIS?

Add this to your Web Config

    <httpRuntime executionTimeout="180" />

Optional TimeSpan attribute.

Specifies the maximum number of seconds that a request is allowed to execute before being automatically shut down by ASP.NET.

This time-out applies only if the debug attribute in the compilation element is False. To help to prevent shutting down the application while you are debugging, do not set this time-out to a large value.

The default is "00:01:50" (110 seconds).

What is meant by the term "hook" in programming?

In VERY short, you can change the code of an API call such as MessageBox to where it does a different function edited by you (globally will work system wide, locally will work process wide).

MySQL error: key specification without a key length

You should define which leading portion of a TEXT column you want to index.

InnoDB has a limitation of 768 bytes per index key and you won't be able to create an index longer than that.

This will work fine:

CREATE TABLE t_length (
      mydata TEXT NOT NULL,
      KEY ix_length_mydata (mydata(255)))

Note that the maximum value of the key size depends on the column charset. It's 767 characters for a single-byte charset like LATIN1 and only 255 characters for UTF8 (MySQL only uses BMP which requires at most 3 bytes per character)

If you need your whole column to be the PRIMARY KEY, calculate SHA1 or MD5 hash and use it as a PRIMARY KEY.

$(document).ready(function(){ Uncaught ReferenceError: $ is not defined

I know this is an old question, and most people have replied with good answers. But for reference and hopefully saving somebody else's time. Check if your function:


is being called after you have loaded the JQuery library

Return value from a VBScript function

To return a value from a VBScript function, assign the value to the name of the function, like this:

Function getNumber
    getNumber = "423"
End Function

How do I set a VB.Net ComboBox default value


you can write this down in your program

Private Sub ComboBoxExp_Load(ByVal sender As System.Object, ByVal e As System.EventArgs)Handles MyBase.Load
    AlarmHourSelect.Text = "YOUR DEFAULT VALUE"
    AlarmMinuteSelect.Text = "YOUR DEFAULT VALUE"
End Sub

so when you start your program, the first thing it would do is set it on your assigned default value and later you can easily select your required option from the drop down list. also keeping the DropDownStyle to DropDownList would make it look more cooler.


How to uninstall pip on OSX?

Since pip is a package, pip uninstall pip Will do it.
EDIT: If that does not work, try sudo -H pip uninstall pip.

A regex for version number parsing

Another try:


This gives the three parts in groups 4,5,6 BUT: They are aligned to the right. So the first non-null one of 4,5 or 6 gives the version field.

  • 1.2.3 gives 1,2,3
  • 1.2.* gives 1,2,*
  • 1.2 gives null,1,2
  • *** gives null,null,*
  • 1.* gives null,1,*

Asus Zenfone 5 not detected by computer

Settings > Storage > Click the USB Icon at the upper right corner > Check your choice

The response content cannot be parsed because the Internet Explorer engine is not available, or

It is sure because the Invoke-WebRequest command has a dependency on the Internet Explorer assemblies and are invoking it to parse the result as per default behaviour. As Matt suggest, you can simply launch IE and make your selection in the settings prompt which is popping up at first launch. And the error you experience will disappear.

But this is only possible if you run your powershell scripts as the same windows user as whom you launched the IE with. The IE settings are stored under your current windows profile. So if you, like me run your task in a scheduler on a server as the SYSTEM user, this will not work.

So here you will have to change your scripts and add the -UseBasicParsing argument, as ijn this example: $WebResponse = Invoke-WebRequest -Uri $url -TimeoutSec 1800 -ErrorAction:Stop -Method:Post -Headers $headers -UseBasicParsing

adding classpath in linux

Important difference between setting Classpath in Windows and Linux is path separator which is ";" (semi-colon) in Windows and ":" (colon) in Linux. Also %PATH% is used to represent value of existing path variable in Windows while ${PATH} is used for same purpose in Linux (in the bash shell). Here is the way to setup classpath in Linux:

export CLASSPATH=${CLASSPATH}:/new/path

but as such Classpath is very tricky and you may wonder why your program is not working even after setting correct Classpath. Things to note:

  1. -cp options overrides CLASSPATH environment variable.
  2. Classpath defined in Manifest file overrides both -cp and CLASSPATH envorinment variable.

Reference: How Classpath works in Java.

CSS Progress Circle

I created a fiddle using only CSS.

.wrapper {_x000D_
  width: 100px; /* Set the size of the progress bar */_x000D_
  height: 100px;_x000D_
  position: absolute; /* Enable clipping */_x000D_
  clip: rect(0px, 100px, 100px, 50px); /* Hide half of the progress bar */_x000D_
/* Set the sizes of the elements that make up the progress bar */_x000D_
.circle {_x000D_
  width: 80px;_x000D_
  height: 80px;_x000D_
  border: 10px solid green;_x000D_
  border-radius: 50px;_x000D_
  position: absolute;_x000D_
  clip: rect(0px, 50px, 100px, 0px);_x000D_
/* Using the data attributes for the animation selectors. */_x000D_
/* Base settings for all animated elements */_x000D_
div[data-anim~=base] {_x000D_
  -webkit-animation-iteration-count: 1;  /* Only run once */_x000D_
  -webkit-animation-fill-mode: forwards; /* Hold the last keyframe */_x000D_
  -webkit-animation-timing-function:linear; /* Linear animation */_x000D_
.wrapper[data-anim~=wrapper] {_x000D_
  -webkit-animation-duration: 0.01s; /* Complete keyframes asap */_x000D_
  -webkit-animation-delay: 3s; /* Wait half of the animation */_x000D_
  -webkit-animation-name: close-wrapper; /* Keyframes name */_x000D_
.circle[data-anim~=left] {_x000D_
  -webkit-animation-duration: 6s; /* Full animation time */_x000D_
  -webkit-animation-name: left-spin;_x000D_
.circle[data-anim~=right] {_x000D_
  -webkit-animation-duration: 3s; /* Half animation time */_x000D_
  -webkit-animation-name: right-spin;_x000D_
/* Rotate the right side of the progress bar from 0 to 180 degrees */_x000D_
@-webkit-keyframes right-spin {_x000D_
  from {_x000D_
    -webkit-transform: rotate(0deg);_x000D_
  to {_x000D_
    -webkit-transform: rotate(180deg);_x000D_
/* Rotate the left side of the progress bar from 0 to 360 degrees */_x000D_
@-webkit-keyframes left-spin {_x000D_
  from {_x000D_
    -webkit-transform: rotate(0deg);_x000D_
  to {_x000D_
    -webkit-transform: rotate(360deg);_x000D_
/* Set the wrapper clip to auto, effectively removing the clip */_x000D_
@-webkit-keyframes close-wrapper {_x000D_
  to {_x000D_
    clip: rect(auto, auto, auto, auto);_x000D_
<div class="wrapper" data-anim="base wrapper">_x000D_
  <div class="circle" data-anim="base left"></div>_x000D_
  <div class="circle" data-anim="base right"></div>_x000D_

Also check this fiddle here (CSS only)

@import url(,300,400);_x000D_
.arc1 {_x000D_
    width: 160px;_x000D_
    height: 160px;_x000D_
    background: #00a0db;_x000D_
    -webkit-transform-origin: -31% 61%;_x000D_
    margin-left: -30px;_x000D_
    margin-top: 20px;_x000D_
    -webkit-transform: translate(-54px,50px);_x000D_
    -moz-transform: translate(-54px,50px);_x000D_
    -o-transform: translate(-54px,50px);_x000D_
.arc2 {_x000D_
    width: 160px;_x000D_
    height: 160px;_x000D_
    background: #00a0db;_x000D_
    -webkit-transform: skew(45deg,0deg);_x000D_
    -moz-transform: skew(45deg,0deg);_x000D_
    -o-transform: skew(45deg,0deg);_x000D_
    margin-left: -180px;_x000D_
    margin-top: -90px;_x000D_
    position: absolute;_x000D_
    -webkit-transition: all .5s linear;_x000D_
    -moz-transition: all .5s linear;_x000D_
    -o-transition: all .5s linear;_x000D_
.arc-container:hover .arc2 {_x000D_
    margin-left: -50px;_x000D_
    -webkit-transform: skew(-20deg,0deg);_x000D_
    -moz-transform: skew(-20deg,0deg);_x000D_
    -o-transform: skew(-20deg,0deg);_x000D_
.arc-wrapper {_x000D_
    width: 150px;_x000D_
    height: 150px;_x000D_
    background: #424242;_x000D_
    left: 50px;_x000D_
    top: 50px;_x000D_
    position: absolute;_x000D_
.arc-hider {_x000D_
    width: 150px;_x000D_
    height: 150px;_x000D_
    border-radius: 150px;_x000D_
    border: 50px solid #e9e9e9;_x000D_
    box-shadow:inset 0px 0px 20px rgba(0,0,0,0.7);_x000D_
.arc-inset  {_x000D_
    font-family: "Josefin Sans";_x000D_
    font-weight: 100;_x000D_
    position: absolute;_x000D_
    font-size: 413px;_x000D_
    margin-top: -64px;_x000D_
    z-index: 5;_x000D_
    left: 30px;_x000D_
    line-height: 327px;_x000D_
    height: 280px;_x000D_
    -webkit-mask-image: -webkit-linear-gradient(top, rgba(0,0,0,1), rgba(0,0,0,0.2));_x000D_
.arc-lowerInset {_x000D_
    font-family: "Josefin Sans";_x000D_
    font-weight: 100;_x000D_
    position: absolute;_x000D_
    font-size: 413px;_x000D_
    margin-top: -64px;_x000D_
    z-index: 5;_x000D_
    left: 30px;_x000D_
    line-height: 327px;_x000D_
    height: 280px;_x000D_
    color: white;_x000D_
    -webkit-mask-image: -webkit-linear-gradient(top, rgba(0,0,0,0.2), rgba(0,0,0,1));_x000D_
.arc-overlay {_x000D_
    width: 100px;_x000D_
    height: 100px;_x000D_
    background-image: linear-gradient(bottom, rgb(217,217,217) 10%, rgb(245,245,245) 90%, rgb(253,253,253) 100%);_x000D_
    background-image: -o-linear-gradient(bottom, rgb(217,217,217) 10%, rgb(245,245,245) 90%, rgb(253,253,253) 100%);_x000D_
    background-image: -moz-linear-gradient(bottom, rgb(217,217,217) 10%, rgb(245,245,245) 90%, rgb(253,253,253) 100%);_x000D_
    background-image: -webkit-linear-gradient(bottom, rgb(217,217,217) 10%, rgb(245,245,245) 90%, rgb(253,253,253) 100%);_x000D_
    padding-left: 32px;_x000D_
    box-sizing: border-box;_x000D_
    -moz-box-sizing: border-box;_x000D_
    line-height: 100px;_x000D_
    font-family: sans-serif;_x000D_
    font-weight: 400;_x000D_
    text-shadow: 0 1px 0 #fff;_x000D_
    font-size: 22px;_x000D_
    border-radius: 100px;_x000D_
    position: absolute;_x000D_
    z-index: 5;_x000D_
    top: 75px;_x000D_
    left: 75px;_x000D_
    box-shadow:0px 0px 20px rgba(0,0,0,0.7);_x000D_
.arc-container {_x000D_
    position: relative;_x000D_
    background: #e9e9e9;_x000D_
    height: 250px;_x000D_
    width: 250px;_x000D_
<div class="arc-container">_x000D_
    <div class="arc-hider"></div>_x000D_
    <div class="arc-inset">_x000D_
    <div class="arc-lowerInset">_x000D_
    <div class="arc-overlay">_x000D_
    <div class="arc-wrapper">_x000D_
        <div class="arc2"></div>_x000D_
        <div class="arc1"></div>_x000D_

Or this beautiful round progress bar with HTML5, CSS3 and JavaScript.

Better way to sort array in descending order

For in-place sorting in descending order:

int[] numbers = { 1, 2, 3 };
Array.Sort(numbers, (a, b) => b.CompareTo(a));

For out-of-place sorting (no changes to input array):

int[] numbers = { 1, 2, 3 };
var sortedNumbers = numbers.OrderByDescending(x => x).ToArray();

how to get file path from sd card in android

You can get the path of sdcard from this code:

File extStore = Environment.getExternalStorageDirectory();

Then specify the foldername and file name

for e.g:


How do I create sql query for searching partial matches?

First of all, this approach won't scale in the large, you'll need a separate index from words to item (like an inverted index).

If your data is not large, you can do

SELECT DISTINCT(name) FROM mytable WHERE name LIKE '%mall%' OR description LIKE '%mall%'

using OR if you have multiple keywords.

How to style the parent element when hovering a child element?

Another, simpler approach (to an old question)..
would be to place elements as siblings and use:

Adjacent Sibling Selector (+) or General Sibling Selector (~)

<div id="parent">
  <!-- control should come before the target... think "cascading" ! -->
  <button id="control">Hover Me!</button>
  <div id="target">I'm hovered too!</div>
#parent {
  position: relative;
  height: 100px;

/* Move button control to bottom. */
#control {
  position: absolute;
  bottom: 0;

#control:hover ~ #target {
  background: red;

enter image description here

Demo Fiddle here.

Change user-agent for Selenium web-driver

This is a short solution to change the request UserAgent on the fly.

Change UserAgent of a request with Chrome

from selenium import webdriver
from selenium.webdriver.common.desired_capabilities import DesiredCapabilities

driver = webdriver.Chrome(driver_path)
driver.execute_cdp_cmd('Network.setUserAgentOverride', {"userAgent":"python 2.7", "platform":"Windows"})

then return your useragent:

agent = driver.execute_script("return navigator.userAgent")

Some sources

The source code of from SeleniumHQ ( extends its functionalities through the Chrome Devtools Protocol

def execute_cdp_cmd(self, cmd, cmd_args):
        Execute Chrome Devtools Protocol command and get returned result

We can use the Chrome Devtools Protocol Viewer to list more extended functionalities ( as well as the parameters type to use.

What is the optimal algorithm for the game 2048?

I copy here the content of a post on my blog

The solution I propose is very simple and easy to implement. Although, it has reached the score of 131040. Several benchmarks of the algorithm performances are presented.



Heuristic scoring algorithm

The assumption on which my algorithm is based is rather simple: if you want to achieve higher score, the board must be kept as tidy as possible. In particular, the optimal setup is given by a linear and monotonic decreasing order of the tile values. This intuition will give you also the upper bound for a tile value: s where n is the number of tile on the board.

(There's a possibility to reach the 131072 tile if the 4-tile is randomly generated instead of the 2-tile when needed)

Two possible ways of organizing the board are shown in the following images:

enter image description here

To enforce the ordination of the tiles in a monotonic decreasing order, the score si computed as the sum of the linearized values on the board multiplied by the values of a geometric sequence with common ratio r<1 .



Several linear path could be evaluated at once, the final score will be the maximum score of any path.

Decision rule

The decision rule implemented is not quite smart, the code in Python is presented here:

def nextMove(board,recursion_depth=3):
    m,s = AI.nextMoveRecur(board,recursion_depth,recursion_depth)
    return m

def nextMoveRecur(board,depth,maxDepth,base=0.9):
    bestScore = -1.
    bestMove = 0
    for m in range(1,5):
            newBoard = copy.deepcopy(board)

            score = AI.evaluate(newBoard)
            if depth != 0:
                my_m,my_s = AI.nextMoveRecur(newBoard,depth-1,maxDepth)
                score += my_s*pow(base,maxDepth-depth+1)

            if(score > bestScore):
                bestMove = m
                bestScore = score
    return (bestMove,bestScore);

An implementation of the minmax or the Expectiminimax will surely improve the algorithm. Obviously a more sophisticated decision rule will slow down the algorithm and it will require some time to be implemented.I will try a minimax implementation in the near future. (stay tuned)


  • T1 - 121 tests - 8 different paths - r=0.125
  • T2 - 122 tests - 8-different paths - r=0.25
  • T3 - 132 tests - 8-different paths - r=0.5
  • T4 - 211 tests - 2-different paths - r=0.125
  • T5 - 274 tests - 2-different paths - r=0.25
  • T6 - 211 tests - 2-different paths - r=0.5

enter image description here enter image description here enter image description here enter image description here

In case of T2, four tests in ten generate the 4096 tile with an average score of s 42000


The code can be found on GiHub at the following link: It is based on term2048 and it's written in Python. I will implement a more efficient version in C++ as soon as possible.

Group by multiple field names in java 8

The groupingBy method has the first parameter is Function<T,K> where:

@param <T> the type of the input elements

@param <K> the type of the keys

If we replace lambda with the anonymous class in your code, we can see some kind of that: Function<Person, int>() {
            public int apply(Person person) {
                return person.getAge();

Just now change output parameter<K>. In this case, for example, I used a pair class from org.apache.commons.lang3.tuple for grouping by name and age, but you may create your own class for filtering groups as you need. Function<Person, Pair<Integer, String>>() {
                public YourFilter apply(Person person) {
                    return Pair.of(person.getAge(), person.getName());

Finally, after replacing with lambda back, code looks like that:

Map<Pair<Integer,String>, List<Person>> peopleByAgeAndName = people.collect(Collectors.groupingBy(p -> Pair.of(person.getAge(), person.getName()), Collectors.mapping((Person p) -> p, toList())));

In SQL how to compare date values?

Uh, WHERE mydate<='2008-11-25' is the way to do it. That should work.

Do you get an error message? Are you using an ancient version of MySQL?

Edit: The following works fine for me on MySQL 5.x

create temporary table foo(d datetime);
insert into foo(d) VALUES ('2000-01-01');
insert into foo(d) VALUES ('2001-01-01');
select * from foo where d <= '2000-06-01';

How can I set the maximum length of 6 and minimum length of 6 in a textbox?

You can use the HTML5 pattern attribute or use JavaScript.

The pattern could look for example like this:

<input id="groupidtext" type="text" pattern="(.){6,6}" style="width: 100px;" maxlength="6" />

But the pattern attribute will only work with HTML5 browsers. For old browsers you'll need JavaScript.

As suggested in the comments to add, this will only work as soon as a form is about to be submitted. If this input is not in a form and you need validation as a user types, use JavaScript.

How to install toolbox for MATLAB

Use ver it will list all the installed toolboxes and versions of the toolbox.

Javascript Object push() function

Javascript programming language supports functional programming paradigm so you can do easily with these codes.

var data = [
    {"Id": "1", "Status": "Valid"},
    {"Id": "2", "Status": "Invalid"}
var isValid = function(data){
    return data.Status === "Valid";
var valids = data.filter(isValid);

How to search a string in a single column (A) in excel using VBA

Below are two methods that are superior to looping. Both handle a "no-find" case.

  1. The VBA equivalent of a normal function VLOOKUP with error-handling if the variable doesn't exist (INDEX/MATCH may be a better route than VLOOKUP, ie if your two columns A and B were in reverse order, or were far apart)
  2. VBAs FIND method (matching a whole string in column A given I use the xlWhole argument)

    Sub Method1()
    Dim strSearch As String
    Dim strOut As String
    Dim bFailed As Boolean
    strSearch = "trees"
    On Error Resume Next
    strOut = Application.WorksheetFunction.VLookup(strSearch, Range("A:B"), 2, False)
    If Err.Number <> 0 Then bFailed = True
    On Error GoTo 0
    If Not bFailed Then
    MsgBox "corresponding value is " & vbNewLine & strOut
    MsgBox strSearch & " not found"
    End If
    End Sub
    Sub Method2()
        Dim rng1 As Range
        Dim strSearch As String
        strSearch = "trees"
        Set rng1 = Range("A:A").Find(strSearch, , xlValues, xlWhole)
        If Not rng1 Is Nothing Then
            MsgBox "Find has matched " & strSearch & vbNewLine & "corresponding cell is " & rng1.Offset(0, 1)
            MsgBox strSearch & " not found"
        End If
    End Sub

How to set a selected option of a dropdown list control using angular JS

Try the following:

JS file

this.options = { 
        languages: [{language: 'English', lg:'en'}, {language:'German', lg:'de'}]

HTML file

<div class="form-group col-sm-6">
    <label>Preferred language</label>
    <select class="form-control" name="right" ng-model="signinDetails.language" ng-init="signinDetails.language = options.languages[0]" ng-options="l as l.language for l in options.languages"><option></option>

How do you connect to multiple MySQL databases on a single webpage?

$dbh1 = mysql_connect($hostname, $username, $password);  
$dbh2 = mysql_connect($hostname, $username, $password, true); 

mysql_select_db('database1', $dbh1); 

mysql_query('select * from tablename', $dbh1);
mysql_query('select * from tablename', $dbh2);

This is the most obvious solution that I use but just remember, if the username / password for both the database is exactly same in the same host, this solution will always be using the first connection. So don't be confused that this is not working in such case. What you need to do is, create 2 different users for the 2 databases and it will work.

Are HTTPS headers encrypted?

With SSL the encryption is at the transport level, so it takes place before a request is sent.

So everything in the request is encrypted.

How exactly do you configure httpOnlyCookies in ASP.NET?

Interestingly putting <httpCookies httpOnlyCookies="false"/> doesn't seem to disable httpOnlyCookies in ASP.NET 2.0. Check this article about SessionID and Login Problems With ASP .NET 2.0.

Looks like Microsoft took the decision to not allow you to disable it from the web.config. Check this post on

Run Jquery function on window events: load, resize, and scroll?

You can bind listeners to one common functions -

$(window).bind("load resize scroll",function(e){
  // do stuff

Or another way -





Alternatively, instead of using .bind() you can use .on() as bind directly maps to on(). And maybe .bind() won't be there in future jquery versions.





SQL Server convert string to datetime

For instance you can use

update tablename set datetimefield='19980223 14:23:05'
update tablename set datetimefield='02/23/1998 14:23:05'
update tablename set datetimefield='1998-12-23 14:23:05'
update tablename set datetimefield='23 February 1998 14:23:05'
update tablename set datetimefield='1998-02-23T14:23:05'

You need to be careful of day/month order since this will be language dependent when the year is not specified first. If you specify the year first then there is no problem; date order will always be year-month-day.

Alternative to file_get_contents?

If you have it available, using curl is your best option.

You can see if it is enabled by doing phpinfo() and searching the page for curl.

If it is enabled, try this:

curl_setopt($curl_handle, CURLOPT_URL, SITE_PATH . 'cms/data.php');
$xml_file = curl_exec($curl_handle);

How to protect Excel workbook using VBA?

  1. in your sample code you must remove the brackets, because it's not a functional assignment; also for documentary reasons I would suggest you use the := notation (see code sample below)

    1. Application.Thisworkbook refers to the book containing the VBA code, not necessarily the book containing the data, so be cautious.

Express the sheet you're working on as a sheet object and pass it, together with a logical variable to the following sub:

Sub SetProtectionMode(MySheet As Worksheet, ProtectionMode As Boolean)

    If ProtectionMode Then
        MySheet.Protect DrawingObjects:=True, Contents:=True, _
                        AllowSorting:=True, AllowFiltering:=True
    End If
End Sub

Within the .Protect method you can define what you want to allow/disallow. This code block will switch protection on/off - without password in this example, you can add it as a parameter or hardcoded within the Sub. Anyway somewhere the PW will be hardcoded. If you don't want this, just call the Protection Dialog window and let the user decide what to do:


Hope that helps

Good luck - MikeD

Python return statement error " 'return' outside function"

As per the documentation on the return statement, return may only occur syntactically nested in a function definition. The same is true for yield.

Apply CSS styles to an element depending on its child elements

As far as I'm aware, styling a parent element based on the child element is not an available feature of CSS. You'll likely need scripting for this.

It'd be wonderful if you could do something like div[div.a] or div:containing[div.a] as you said, but this isn't possible.

You may want to consider looking at jQuery. Its selectors work very well with 'containing' types. You can select the div, based on its child contents and then apply a CSS class to the parent all in one line.

If you use jQuery, something along the lines of this would may work (untested but the theory is there):

$('div:has(div.a)').css('border', '1px solid red');



combined with a CSS class:

    border: 1px solid red;

Here's the documentation for the jQuery "has" selector.

How to export datagridview to excel using

A simple way of generating a printable report from a Datagridview is to place the datagridview on a Panel object. It is possible to draw a bitmap of the panel.

Here's how I do it.

'create the bitmap with the dimentions of the Panel Dim bmp As New Bitmap(Panel1.Width, Panel1.Height)

'draw the Panel to the bitmap "bmp" Panel1.DrawToBitmap(bmp, Panel1.ClientRectangle)

I create a multi page tiff by "breaking my datagridview items into pages. this is how i detect the start of a new page:

'i add the rows to my datagrid one at a time and then check if the scrollbar is active. 'if the scrollbar is active i save the row to a variable and then i remove it from the 'datagridview and roll back my counter integer by one(thus the next run will include this 'row.

Private Function VScrollBarVisible() As Boolean
    Dim ctrl As New Control
    For Each ctrl In DataGridView_Results.Controls
        If ctrl.GetType() Is GetType(VScrollBar) Then
            If ctrl.Visible = True Then
                Return True
                Return False
            End If
        End If
    Return Nothing
End Function

I hope this helps

Python: PIP install path, what is the correct location for this and other addons?

Since pip is an executable and which returns path of executables or filenames in environment. It is correct. Pip module is installed in site-packages but the executable is installed in bin.

Can I remove the URL from my print css, so the web address doesn't print?

Use that code.that will help to solve your problem

@media print 
  @page { margin: 0; }
  body  { margin: 1.6cm; }

Oracle insert if not exists statement

The correct way to insert something (in Oracle) based on another record already existing is by using the MERGE statement.

Please note that this question has already been answered here on SO:

Total width of element (including padding and border) in jQuery

Just for simplicity I encapsulated Andreas Grech's great answer above in some functions. For those who want a bit of cut-and-paste happiness.

function getTotalWidthOfObject(object) {

    if(object == null || object.length == 0) {
        return 0;

    var value       = object.width();
    value           += parseInt(object.css("padding-left"), 10) + parseInt(object.css("padding-right"), 10); //Total Padding Width
    value           += parseInt(object.css("margin-left"), 10) + parseInt(object.css("margin-right"), 10); //Total Margin Width
    value           += parseInt(object.css("borderLeftWidth"), 10) + parseInt(object.css("borderRightWidth"), 10); //Total Border Width
    return value;

function  getTotalHeightOfObject(object) {

    if(object == null || object.length == 0) {
        return 0;

    var value       = object.height();
    value           += parseInt(object.css("padding-top"), 10) + parseInt(object.css("padding-bottom"), 10); //Total Padding Width
    value           += parseInt(object.css("margin-top"), 10) + parseInt(object.css("margin-bottom"), 10); //Total Margin Width
    value           += parseInt(object.css("borderTopWidth"), 10) + parseInt(object.css("borderBottomWidth"), 10); //Total Border Width
    return value;

What is the best way to concatenate two vectors?

One more simple variant which was not yet mentioned:


And using merge algorithm:

#include <algorithm> #include <vector> #include <iterator> #include <iostream> #include <sstream> #include <string> template<template<typename, typename...> class Container, class T> std::string toString(const Container<T>& v) { std::stringstream ss; std::copy(v.begin(), v.end(), std::ostream_iterator<T>(ss, "")); return ss.str(); }; int main() { std::vector<int> A(10); std::vector<int> B(5); //zero filled std::vector<int> AB(15); std::for_each(A.begin(), A.end(), [](int& f)->void { f = rand() % 100; }); std::cout << "before merge: " << toString(A) << "\n"; std::cout << "before merge: " << toString(B) << "\n"; merge(B.begin(),B.end(), begin(A), end(A), AB.begin(), [](int&,int&)->bool {}); std::cout << "after merge: " << toString(AB) << "\n"; return 1; }

How can I check what version/edition of Visual Studio is installed programmatically?

An updated answer to this question would be the following :

"C:\Program Files (x86)\Microsoft Visual Studio\Installer\vswhere.exe" -latest -property productId

Resolves to 2019

"C:\Program Files (x86)\Microsoft Visual Studio\Installer\vswhere.exe" -latest -property catalog_productLineVersion

Resolves to Microsoft.VisualStudio.Product.Professional

How to update a single library with Composer?

You can basically do following one to install new package as well.

php composer.phar require

then terminal will ask you to enter the name of the package for searching.

$ Search for a package []: //Your package name here

Then terminal will ask the version of the package (If you would like to have the latest version just leave it blank)

$ Enter the version constraint to require (or leave blank to use the latest version) []: //your version number here

Then you just press the return key. Terminal will ask for another package, if you dont want to install another one just press the return key and you will be done.

jQuery $.ajax(), $.post sending "OPTIONS" as REQUEST_METHOD in Firefox

I used a proxy url to solve a similar problem when I want to post data to my apache solr hosted in another server. (This may not be the perfect answer but it solves my problem.)

Follow this URL: Using Mode-Rewrite for proxying, I add this line to my httpd.conf:

 RewriteRule ^solr/(.*)$ http://ip:8983/solr$1 [P]

Therefore, I can just post data to /solr instead of posting data to http://ip:8983/solr/*. Then it will be posting data in the same origin.

Differences between Lodash and Underscore.js

If, like me, you were expecting a list of usage differences between Underscore.js and Lodash, there's a guide for migrating from Underscore.js to Lodash.

Here's the current state of it for posterity:

  • Underscore _.any is Lodash _.some
  • Underscore _.all is Lodash _.every
  • Underscore _.compose is Lodash _.flowRight
  • Underscore _.contains is Lodash _.includes
  • Underscore _.each doesn’t allow exiting by returning false
  • Underscore _.findWhere is Lodash _.find
  • Underscore _.flatten is deep by default while Lodash is shallow
  • Underscore _.groupBy supports an iteratee that is passed the parameters (value, index, originalArray), while in Lodash, the iteratee for _.groupBy is only passed a single parameter: (value).
  • Underscore.js _.indexOf with third parameter undefined is Lodash _.indexOf
  • Underscore.js _.indexOf with third parameter true is Lodash _.sortedIndexOf
  • Underscore _.indexBy is Lodash _.keyBy
  • Underscore _.invoke is Lodash _.invokeMap
  • Underscore _.mapObject is Lodash _.mapValues
  • Underscore _.max combines Lodash _.max & _.maxBy
  • Underscore _.min combines Lodash _.min & _.minBy
  • Underscore _.sample combines Lodash _.sample & _.sampleSize
  • Underscore _.object combines Lodash _.fromPairs and _.zipObject
  • Underscore _.omit by a predicate is Lodash _.omitBy
  • Underscore _.pairs is Lodash _.toPairs
  • Underscore _.pick by a predicate is Lodash _.pickBy
  • Underscore _.pluck is Lodash
  • Underscore _.sortedIndex combines Lodash _.sortedIndex & _.sortedIndexOf
  • Underscore _.uniq by an iteratee is Lodash _.uniqBy
  • Underscore _.where is Lodash _.filter
  • Underscore _.isFinite doesn’t align with Number.isFinite
    (e.g. _.isFinite('1') returns true in Underscore.js, but false in Lodash)
  • Underscore _.matches shorthand doesn’t support deep comparisons
    (e.g., _.filter(objects, { 'a': { 'b': 'c' } }))
  • Underscore = 1.7 & Lodash _.template syntax is
    _.template(string, option)(data)
  • Lodash _.memoize caches are Map like objects
  • Lodash doesn’t support a context argument for many methods in favor of _.bind
  • Lodash supports implicit chaining, lazy chaining, & shortcut fusion
  • Lodash split its overloaded _.head, _.last,, & _.initial out into
    _.take, _.takeRight, _.drop, & _.dropRight
    (i.e. _.head(array, 2) in Underscore.js is _.take(array, 2) in Lodash)

enumerate() for dictionary in python

You may find it useful to include index inside key:

d = {'a': 1, 'b': 2}
d = {(i, k): v for i, (k, v) in enumerate(d.items())}


{(0, 'a'): True, (1, 'b'): False}

Compare given date with today


(the w3schools example, it works perfect)

Android Studio - Emulator - eglSurfaceAttrib not implemented

Fix: Unlock your device before running it.

Hi Guys: Think I may have a fix for this:

Sounds ridiculous but try unlocking your Virtual Device; i.e. use your mouse to swipe and open. Your app should then work!!

Android View shadow

This question may be old, but for anybody in future that wants a simple way to achieve complex shadow effects check out my library here

Using the library, you can change shadow colors, tweak edges and so much more. Here's an example to achieve what you seek for.


            app:radius="10dp" />

To change the shadow color, use app:shadowColor="your color code".

C# switch on type

I have used this form of switch-case on rare occasion. Even then I have found another way to do what I wanted. If you find that this is the only way to accomplish what you need, I would recommend @Mark H's solution.

If this is intended to be a sort of factory creation decision process, there are better ways to do it. Otherwise, I really can't see why you want to use the switch on a type.

Here is a little example expanding on Mark's solution. I think it is a great way to work with types:

Dictionary<Type, Action> typeTests;

public ClassCtor()
    typeTests = new Dictionary<Type, Action> ();

    typeTests[typeof(int)] = () => DoIntegerStuff();
    typeTests[typeof(string)] = () => DoStringStuff();
    typeTests[typeof(bool)] = () => DoBooleanStuff();

private void DoBooleanStuff()
   //do stuff

private void DoStringStuff()
    //do stuff

private void DoIntegerStuff()
    //do stuff

public Action CheckTypeAction(Type TypeToTest)
    if (typeTests.Keys.Contains(TypeToTest))
        return typeTests[TypeToTest];

    return null; // or some other Action delegate

CSS :selected pseudo class similar to :checked, but for <select> elements

the :checked pseudo-class initially applies to such elements that have the HTML4 selected and checked attributes


So, this CSS works, although styling the color is not possible in every browser:

option:checked { color: red; }

An example of this in action, hiding the currently selected item from the drop down list.

option:checked { display:none; }

To style the currently selected option in the closed dropdown as well, you could try reversing the logic:

select { color: red; }
option:not(:checked) { color: black; } /* or whatever your default style is */

How do I reverse an int array in Java?

Try this program in JAVA :-

import java.util.Scanner;

public class Rev_one_D {

    static int row;

    static int[] trans_arr = new int[row];

    public static void main(String[] args) {
        Scanner sc = new Scanner(;
        int n = sc.nextInt();
        row = n;

        int[] arr = new int[row];
        for (int i = 0; i < row; i++) {

            arr[i] = sc.nextInt();
            System.out.print(arr[i] + " ");


        for (int i = 0; i < arr.length / 2; i++) {
            int temp = arr[i];
            arr[i] = arr[arr.length - i - 1];
            arr[arr.length - i - 1] = temp;


        for (int i = 0; i < row; i++) {
            System.out.print(arr[i] + " ");

What's onCreate(Bundle savedInstanceState)

As Dhruv Gairola answered, you can save the state of the application by using Bundle savedInstanceState. I am trying to give a very simple example that new learners like me can understand easily.

Suppose, you have a simple fragment with a TextView and a Button. Each time you clicked the button the text changes. Now, change the orientation of you device/emulator and notice that you lost the data (means the changed data after clicking you got) and fragment starts as the first time again. By using Bundle savedInstanceState we can get rid of this. If you take a look into the life cyle of the fragment.Fragment Lifecylce you will get that a method "onSaveInstanceState" is called when the fragment is about to destroyed.

So, we can save the state means the changed text value into that bundle like this

 int counter  = 0;
 public void onSaveInstanceState(Bundle outState) {

After you make the orientation the "onCreate" method will be called right? so we can just do this

public void onCreate(Bundle savedInstanceState) {

    if(savedInstanceState == null){
        //it is the first time the fragment is being called
        counter = 0;
        //not the first time so we will check SavedInstanceState bundle
        counter = savedInstanceState.getInt("value",0); //here zero is the default value

Now, you won't lose your value after the orientation. The modified value always will be displayed.

How do I break a string across more than one line of code in JavaScript?

In your example, you can break the string into two pieces:

alert ( "Please Select file"
 + " to delete");

Or, when it's a string, as in your case, you can use a backslash as @Gumbo suggested:

alert ( "Please Select file\
 to delete");

Note that this backslash approach is not necessarily preferred, and possibly not universally supported (I had trouble finding hard data on this). It is not in the ECMA 5.1 spec.

When working with other code (not in quotes), line breaks are ignored, and perfectly acceptable. For example:

  && SuperLongConditionOnAnotherLine
  && SuperLongConditionOnThirdLineSheesh)
    // launch_missiles();

How to set border on jPanel?

Swing has no idea what the preferred, minimum and maximum sizes of the GoBoard should be as you have no components inside of it for it to calculate based on, so it picks a (probably wrong) default. Since you are doing custom drawing here, you should implement these methods

Dimension getPreferredSize()
Dimension getMinumumSize()
Dimension getMaximumSize()

or conversely, call the setters for these methods.

Pylint "unresolved import" error in Visual Studio Code

In my case I already had a Conda environment activated, but I still wanted local Python modules to be available for autocomplete, peeking definition, etc.

I tried many solutions such as adding a list of Python paths etc., but what finally solved it for me was to create a symbolic link from Conda's lib/python{your version}/site-packages to my local module.

Python: Ignore 'Incorrect padding' error when base64 decoding

It seems you just need to add padding to your bytes before decoding. There are many other answers on this question, but I want to point out that (at least in Python 3.x) base64.b64decode will truncate any extra padding, provided there is enough in the first place.

So, something like: b'abc=' works just as well as b'abc==' (as does b'abc=====').

What this means is that you can just add the maximum number of padding characters that you would ever need—which is three (b'===')—and base64 will truncate any unnecessary ones.

This lets you write:

base64.b64decode(s + b'===')

which is simpler than:

base64.b64decode(s + b'=' * (-len(s) % 4))