Programs & Examples On #Pssnapin

PowerShell snap-ins provides a mechanism for registering sets of cmdlets and another Windows PowerShell provider with the shell. May also refer to the PSSnapIn base class.

How to count objects in PowerShell?

This will get you count:

get-alias | measure

You can work with the result as with object:

$m = get-alias | measure

And if you would like to have aliases in some variable also, you can use Tee-Object:

$m = get-alias | tee -Variable aliases | measure

Some more info on Measure-Object cmdlet is on Technet.

Do not confuse it with Measure-Command cmdlet which is for time measuring. (again on Technet)

Hibernate error - QuerySyntaxException: users is not mapped [from users]

Added @TABLE(name = "TABLE_NAME") annotation and fixed. Check your annotations and hibernate.cfg.xml file. This is the sample entity file that works:

import javax.persistence.*;

@Table(name = "VENDOR")
public class Vendor {

    //~ --- [INSTANCE FIELDS] ------------------------------------------------------------------------------------------
    private int    id;
    private String name;

    //~ --- [METHODS] --------------------------------------------------------------------------------------------------
    public boolean equals(final Object o) {    
        if (this == o) {
            return true;

        if (o == null || getClass() != o.getClass()) {
            return false;

        final Vendor vendor = (Vendor) o;

        if (id != {
            return false;

        if (name != null ? !name.equals( : != null) {
            return false;

        return true;

    //~ ----------------------------------------------------------------------------------------------------------------
    @Column(name = "ID")
    @GeneratedValue(strategy = GenerationType.AUTO)
    public int getId() {
        return id;

    @Column(name = "NAME")
    public String getName() {

        return name;

    public void setId(final int id) { = id;

    public void setName(final String name) {    = name;

    public int hashCode() {
        int result = id;
        result = 31 * result + (name != null ? name.hashCode() : 0);
        return result;

how to rotate a bitmap 90 degrees

If you rotate bitmap, 90 180 270 360 is ok but for other degrees canvas will draw bitmap with different size.

So,the best way is

canvas.rotate(-degree,rotateCenterPoint.x,rotateCenterPoint.y);//rotate back

Eclipse: "'Periodic workspace save.' has encountered a pro?blem."

I fixed mine by closing eclipse and deleting the whole .metadata folder inside my workspace folder.

running multiple bash commands with subprocess

>>> command = "echo a; echo b"
>>> shlex.split(command);
    ['echo', 'a; echo', 'b']

so, the problem is shlex module do not handle ";"

How can I backup a Docker-container with its data-volumes?

I know this is old, but I realize that there isnt a well documented solution to pushing a data container (as backup) to docker hub. I just published a short example on how doing so at

Following is the bottom line

The docker tutorial suggest you can backup and restore the data volume locally. We are going to use this technique, add a few more lines to get this backup pushed into docker hub for easy future restoration to any location we desire. So, lets get started. These are the steps to follow:

Backup the data volume from the data container named data-container-to-backup

docker run --rm --volumes-from data-container-backup --name tmp-backup -v $(pwd):/backup ubuntu tar cvf /backup/backup.tar /folderToBackup

Expand this tar file into a new container so we can commit it as part of its image

docker run -d -v $(pwd):/backup --name data-backup ubuntu /bin/sh -c "cd / && tar xvf /backup/backup.tar"

Commit and push the image with a desired tag ($VERSION)

docker commit data-backup repo/data-backup:$VERSION
docker push repo/data-backup:$VERSION

Finally, lets clean up

docker rm data-backup
docker rmi $(docker images -f "dangling=true" -q)

Now we have an image named data-backup in our repo that is simply a filesystem with the backup files and folders. In order use this image (aka restore from backup), we do the following:

Run the data container with the data-backup image

run -v /folderToBackup --entrypoint "bin/sh" --name data-container repo/data-backup:${VERSION}

Run your whatEver image with volumes from the data-conainter

docker run --volumes-from=data-container repo/whatEver

Thats it.

I was surprised there is no documentation for this work around. I hope someone find this helpful. I know it took me a while to think about this.

How to zero pad a sequence of integers in bash so that all have the same width?

If you're just after padding numbers with zeros to achieve fixed length, just add the nearest multiple of 10 eg. for 2 digits, add 10^2, then remove the first 1 before displaying output.

This solution works to pad/format single numbers of any length, or a whole sequence of numbers using a for loop.

# Padding 0s zeros:
# Pure bash without externals eg. awk, sed, seq, head, tail etc.
# works with echo, no need for printf

pad=100000      ;# 5 digit fixed

for i in {0..99999}; do ((j=pad+i))
    echo ${j#?}

Tested on Mac OSX 10.6.8, Bash ver 3.2.48

Django TemplateDoesNotExist?

Works on Django 3

I found I believe good way, I have the base.html in root folder, and all other html files in App folders, I

import os

# This settings are to allow store templates,static and media files in root folder

BASE_DIR = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
TEMPLATE_DIR = os.path.join(BASE_DIR,'templates')
STATIC_DIR = os.path.join(BASE_DIR,'static')
MEDIA_DIR = os.path.join(BASE_DIR,'media')

# This is default path from Django, must be added 
#AFTER our BASE_DIR otherwise DB will be broken.
BASE_DIR = Path(__file__).resolve().parent.parent

# add your apps to Installed apps

# Now add TEMPLATE_DIR to  'DIRS' where in TEMPLATES like bellow
        'BACKEND': 'django.template.backends.django.DjangoTemplates',
        'APP_DIRS': True,
        'OPTIONS': {
            'context_processors': [
# On end of put this refferences to Static and Media files
STATIC_URL = '/static/'

MEDIA_URL = '/media/'

If you have problem with Database, please check if you put the original BASE_DIR bellow the new BASE_DIR otherwise change

# Original
'NAME': BASE_DIR / 'db.sqlite3',
# to
'NAME': os.path.join(BASE_DIR,'db.sqlite3'),

Django now will be able to find the HTML and Static files both in the App folders and in Root folder without need of adding the name of App folder in front of the file.

    -static(css,JS ...)
    -templates(base.html, ....)
    -other django files like (, ....)
        -templates(index1.html, other html files can extend now base.html too)
        -other App1 files
        -templates(index2.html, other html files can extend now base.html too)
        -other App2 files

MATLAB error: Undefined function or method X for input arguments of type 'double'

The error code indicates the function definition cannot be found. Make sure you're calling the function from the same workspace as the divrat.m file is stored. And make sure divrat function is not a subfunction, it should be first function declaration in the file. You can also try to call the function from the same divrat.m file in order to see if the problem is with workspace selection or the function.

By the way, why didn't you simply say

s = sqrt(diag(C));

Wouldn't it be the same?

No connection could be made because the target machine actively refused it?

I faced same error because when your Server and Client run on same machine the Client need server local ip address not Public ip address to communicate with server you need Public ip address only in case when Server and Client run on separate machine so use Local ip address in client program to connect with server Local ip address can be found using this method.

 public static string Getlocalip()
            IPAddress[] localIPs = Dns.GetHostAddresses(Dns.GetHostName());
            return localIPs[7].ToString();
        catch (Exception)

            return "null";


How do I configure different environments in Angular.js?

We could also do something like this.

    'use strict';

    angular.module('app').service('env', function env() {

        var _environments = {
            local: {
                host: 'localhost:3000',
                config: {
                    apiroot: 'http://localhost:3000'
            dev: {
                host: '',
                config: {
                    apiroot: 'http://localhost:3000'
            test: {
                host: '',
                config: {
                    apiroot: 'http://localhost:3000'
            stage: {
                host: '',
                config: {
                apiroot: 'staging'
            prod: {
                host: '',
                config: {
                    apiroot: 'production'

        return {
            getEnvironment: function(){
                var host =;
                    return _environment;

                for(var environment in _environments){
                    if(typeof _environments[environment].host && _environments[environment].host == host){
                        _environment = environment;
                        return _environment;

                return null;
            get: function(property){
                return _environments[this.getEnvironment()].config[property];



And in your controller/service, we can inject the dependency and call the get method with property to be accessed.

(function() {
    'use strict';

    angular.module('app').service('apiService', apiService);

    apiService.$inject = ['configurations', '$q', '$http', 'env'];

    function apiService(config, $q, $http, env) {

        var service = {};
        /* **********APIs **************** */
        service.get = function() {
            return $http.get(env.get('apiroot') + '/api/yourservice');

        return service;


$http.get(env.get('apiroot') would return the url based on the host environment.

Is there a way to "limit" the result with ELOQUENT ORM of Laravel?

Create a Game model which extends Eloquent and use this:


take() here will get 30 records and skip() here will offset to 30 records.

In recent Laravel versions you can also use:


Create a directory if it doesn't exist

Use CreateDirectory (char *DirName, SECURITY_ATTRIBUTES Attribs);

If the function succeeds it returns non-zero otherwise NULL.

Split string into individual words Java

This regex will split word by space like space, tab, line break:

String[] str = s.split("\\s+");

HTML-encoding lost when attribute read from input field

Good answer. Note that if the value to encode is undefined or null with jQuery 1.4.2 you might get errors such as:

jQuery("<div/>").text(value).html is not a function


Uncaught TypeError: Object has no method 'html'

The solution is to modify the function to check for an actual value:

function htmlEncode(value){ 
    if (value) {
        return jQuery('<div/>').text(value).html(); 
    } else {
        return '';

Returning Arrays in Java

If you want to use the numbers method, you need an int array to store the returned value.

public static void main(String[] args){
    int[] someNumbers = numbers();
    //do whatever you want with them...

Check if a path represents a file or a folder

Please stick to the nio API to perform these checks

import java.nio.file.*;

static Boolean isDir(Path path) {
  if (path == null || !Files.exists(path)) return false;
  else return Files.isDirectory(path);

How can I read comma separated values from a text file in Java?

//lat=3434&lon=yy38&rd=1.0&| in that format o/p is displaying

public class ReadText {
    public static void main(String[] args) throws Exception {
        FileInputStream f= new FileInputStream("D:/workplace/sample/bookstore.txt");
        BufferedReader br = new BufferedReader(new InputStreamReader(f));
        String strline;
        StringBuffer sb = new StringBuffer();
        while ((strline = br.readLine()) != null)
            String[] arraylist=StringUtils.split(strline, ",");
            if(arraylist.length == 2){

            } else {
                System.out.println("Error: "+strline);
        System.out.println("Data: "+sb.toString());

Better way to represent array in java properties file

I can suggest using delimiters and using the


Example properties file:

MON=0800#Something#Something1, Something2

prop.load(new FileInputStream("\\\\Myseccretnetwork\\Project\\"));
String[]values = prop.get("MON").toString().split("#");

Hope that helps

Creating a SOAP call using PHP with an XML body

There are a couple of ways to solve this. The least hackiest and almost what you want:

$client = new SoapClient(
        'location' => '',
        'uri' => '',
        'trace' => 1,
        'use' => SOAP_LITERAL,
$params = new \SoapVar("<Acquirer><Id>MyId</Id><UserId>MyUserId</UserId><Password>MyPassword</Password></Acquirer>", XSD_ANYXML);
$result = $client->Echo($params);

This gets you the following XML:

<?xml version="1.0" encoding="UTF-8"?>
<SOAP-ENV:Envelope xmlns:SOAP-ENV="" xmlns:ns1="">

That is almost exactly what you want, except for the namespace on the method name. I don't know if this is a problem. If so, you can hack it even further. You could put the <Echo> tag in the XML string by hand and have the SoapClient not set the method by adding 'style' => SOAP_DOCUMENT, to the options array like this:

$client = new SoapClient(
        'location' => '',
        'uri' => '',
        'trace' => 1,
        'use' => SOAP_LITERAL,
        'style' => SOAP_DOCUMENT,
$params = new \SoapVar("<Echo><Acquirer><Id>MyId</Id><UserId>MyUserId</UserId><Password>MyPassword</Password></Acquirer></Echo>", XSD_ANYXML);
$result = $client->MethodNameIsIgnored($params);

This results in the following request XML:

<SOAP-ENV:Envelope xmlns:SOAP-ENV="">

Finally, if you want to play around with SoapVar and SoapParam objects, you can find a good reference in this comment in the PHP manual: If you get that to work, please let me know, I failed miserably.

How to enable and use HTTP PUT and DELETE with Apache2 and PHP?

IIRC the purpose of the form method attribute was to define different transport methods. Consequently, HTML 5.2 only defines GET, POST, and DIALOG methods for transport and dialog action, not how the server should process the data.

Ruby-on-rails solves this problem by using POST/GET for everything and adding a hidden form variable that defines the actual ReST method. This approach is more clumsy and error-prone, but does remove the burden from both the HTML standard and browser developers.

The form method was defined before ReST, so you cannot define ReST in HTML, even after enabling Apache and PHP because the browsers conform to HTML and therefore default to GET/POST for all non-HTML defined values. That means, when you send a form to the browser with a PUT method, the browser changes that to GET and uses that instead. The hidden variable, however, passes through everything unchanged, so you can use that to customise your form handling process.

Hope that helps

CSS Outside Border

IsisCode gives you a good solution. Another one is to position border div inside parent div. Check this example

UPD: You can also use pseudo element :after (:before), in this case HTML will not be polluted with extra markup:

.my-div {
    position: relative;
    padding: 4px;
.my-div:after {
    content: '';
    position: absolute;
    top: -3px;
    left: -3px;
    bottom: -3px;
    right: -3px;
    border: 1px #888 solid;


Get the current time in C

If you just need the time without the date.

  time_t rawtime;
  struct tm * timeinfo;
  time( &rawtime );
  timeinfo = localtime( &rawtime );
  printf("%02d:%02d:%02d", timeinfo->tm_hour, timeinfo->tm_min, 

Are iframes considered 'bad practice'?

It's worth noting that iframes will, regardless of the speed of your users' internet connection or the contents of the iframe, cause a small (0.3s or so) but noticeable slowdown in the speed your page downloads. This is not something you'll see when testing it locally. Actually, this is true for any element added to a page, but iframes seem to be worse.

Mysql password expired. Can't connect

WARNING: this will allow any user to login

I had to try something else. Since my root password expired and altering was not an option because

Column count of mysql.user is wrong. Expected 45, found 46. The table is probably corrupted

temporarly adding skip-grant-tables under [mysqld] in my.cnf and restarting mysql did the trick

Script to Change Row Color when a cell changes text

//Sets the row color depending on the value in the "Status" column.
function setRowColors() {
  var range = SpreadsheetApp.getActiveSheet().getDataRange();
  var statusColumnOffset = getStatusColumnOffset();

  for (var i = range.getRow(); i < range.getLastRow(); i++) {
    rowRange = range.offset(i, 0, 1);
    status = rowRange.offset(0, statusColumnOffset).getValue();
    if (status == 'Completed') {
    } else if (status == 'In Progress') {
    } else if (status == 'Not Started') {

//Returns the offset value of the column titled "Status"
//(eg, if the 7th column is labeled "Status", this function returns 6)
function getStatusColumnOffset() {
  lastColumn = SpreadsheetApp.getActiveSheet().getLastColumn();
  var range = SpreadsheetApp.getActiveSheet().getRange(1,1,1,lastColumn);

  for (var i = 0; i < range.getLastColumn(); i++) {
    if (range.offset(0, i, 1, 1).getValue() == "Status") {
      return i;

Converting UTF-8 to ISO-8859-1 in Java - how to keep it as single byte

If you have the correct encoding in the string, you need not do more to get the bytes for another encoding.

public static void main(String[] args) throws Exception {
            new String(new byte[] { (byte) 0xE2 }, "ISO-8859-1"));
            new String(new byte[] { (byte) 0xC3, (byte) 0xA2 }, "UTF-8"));

private static void printBytes(String str) {
    System.out.println("Bytes in " + str + " with ISO-8859-1");
    for (byte b : str.getBytes(StandardCharsets.ISO_8859_1)) {
        System.out.printf("%3X", b);
    System.out.println("Bytes in " + str + " with UTF-8");
    for (byte b : str.getBytes(StandardCharsets.UTF_8)) {
        System.out.printf("%3X", b);


Bytes in â with ISO-8859-1
Bytes in â with UTF-8
 C3 A2

What is a NoReverseMatch error, and how do I fix it?

The NoReverseMatch error is saying that Django cannot find a matching url pattern for the url you've provided in any of your installed app's urls.

The NoReverseMatch exception is raised by django.core.urlresolvers when a matching URL in your URLconf cannot be identified based on the parameters supplied.

To start debugging it, you need to start by disecting the error message given to you.

  • NoReverseMatch at /my_url/

    This is the url that is currently being rendered, it is this url that your application is currently trying to access but it contains a url that cannot be matched

  • Reverse for 'my_url_name'

    This is the name of the url that it cannot find

  • with arguments '()' and

    These are the non-keyword arguments its providing to the url

  • keyword arguments '{}' not found.

    These are the keyword arguments its providing to the url

  • n pattern(s) tried: []

    These are the patterns that it was able to find in your files that it tried to match against

Start by locating the code in your source relevant to the url that is currently being rendered - the url, the view, and any templates involved. In most cases, this will be the part of the code you're currently developing.

Once you've done this, read through the code in the order that django would be following until you reach the line of code that is trying to construct a url for your my_url_name. Again, this is probably in a place you've recently changed.

Now that you've discovered where the error is occuring, use the other parts of the error message to work out the issue.

The url name

  • Are there any typos?
  • Have you provided the url you're trying to access the given name?
  • If you have set app_name in the app's (e.g. app_name = 'my_app') or if you included the app with a namespace (e.g. include('myapp.urls', namespace='myapp'), then you need to include the namespace when reversing, e.g. {% url 'myapp:my_url_name' %} or reverse('myapp:my_url_name').

Arguments and Keyword Arguments

The arguments and keyword arguments are used to match against any capture groups that are present within the given url which can be identified by the surrounding () brackets in the url pattern.

Assuming the url you're matching requires additional arguments, take a look in the error message and first take a look if the value for the given arguments look to be correct.

If they aren't correct:

  • The value is missing or an empty string

    This generally means that the value you're passing in doesn't contain the value you expect it to be. Take a look where you assign the value for it, set breakpoints, and you'll need to figure out why this value doesn't get passed through correctly.

  • The keyword argument has a typo

    Correct this either in the url pattern, or in the url you're constructing.

If they are correct:

  • Debug the regex

    You can use a website such as regexr to quickly test whether your pattern matches the url you think you're creating, Copy the url pattern into the regex field at the top, and then use the text area to include any urls that you think it should match against.

    Common Mistakes:

    • Matching against the . wild card character or any other regex characters

      Remember to escape the specific characters with a \ prefix

    • Only matching against lower/upper case characters

      Try using either a-Z or \w instead of a-z or A-Z

  • Check that pattern you're matching is included within the patterns tried

    If it isn't here then its possible that you have forgotten to include your app within the INSTALLED_APPS setting (or the ordering of the apps within INSTALLED_APPS may need looking at)

Django Version

In Django 1.10, the ability to reverse a url by its python path was removed. The named path should be used instead.

If you're still unable to track down the problem, then feel free to ask a new question that includes what you've tried, what you've researched (You can link to this question), and then include the relevant code to the issue - the url that you're matching, any relevant url patterns, the part of the error message that shows what django tried to match, and possibly the INSTALLED_APPS setting if applicable.


You can also just add an ON CONFLICT REPLACE clause to your user_name unique constraint and then just INSERT away, leaving it to SQLite to figure out what to do in case of a conflict. See:

Also note the sentence regarding delete triggers: When the REPLACE conflict resolution strategy deletes rows in order to satisfy a constraint, delete triggers fire if and only if recursive triggers are enabled.

Difference between Groovy Binary and Source release?

The source release is the raw, uncompiled code. You could read it yourself. To use it, it must be compiled on your machine. Binary means the code was compiled into a machine language format that the computer can read, then execute. No human can understand the binary file unless its been dissected, or opened with some program that let's you read the executable as code.

Trigger to fire only if a condition is met in SQL Server

Your where clause should have worked. I am at a loss as to why it didn't. Let me show you how I would have figured out the problem with the where clause as it might help you for the future.

When I create triggers, I start at the query window by creating a temp table called #inserted (and or #deleted) with all the columns of the table. Then I popultae it with typical values (Always multiple records and I try to hit the test cases in the values)

Then I write my triggers logic and I can test without it actually being in a trigger. In a case like your where clause not doing what was expected, I could easily test by commenting out the insert to see what the select was returning. I would then probably be easily able to see what the problem was. I assure you that where clasues do work in triggers if they are written correctly.

Once I know that the code works properly for all the cases, I global replace #inserted with inserted and add the create trigger code around it and voila, a tested trigger.

AS I said in a comment, I have a concern that the solution you picked will not work properly in a multiple record insert or update. Triggers should always be written to account for that as you cannot predict if and when they will happen (and they do happen eventually to pretty much every table.)

How to Select a substring in Oracle SQL up to a specific character?

Using a combination of SUBSTR, INSTR, and NVL (for strings without an underscore) will return what you want:

SELECT NVL(SUBSTR('ABC_blah', 0, INSTR('ABC_blah', '_')-1), 'ABC_blah') AS output




SELECT NVL(SUBSTR(t.column, 0, INSTR(t.column, '_')-1), t.column) AS output



If using Oracle10g+, you can use regex via REGEXP_SUBSTR.

MS SQL compare dates?

I am always used DateDiff(day,date1,date2) to compare two date.

Checkout following example. Just copy that and run in Ms sql server. Also, try with change date by 31 dec to 30 dec and check result


declare @firstDate datetime
declare @secondDate datetime

declare @chkDay int

set @firstDate ='2010-12-31 15:13:48.593'
set @secondDate ='2010-12-31 00:00:00.000'

set @chkDay=Datediff(day,@firstDate ,@secondDate )

if @chkDay=0
        Print 'Date is Same'
        Print 'Date is not Same'

What is the HTML tabindex attribute?

It can be used to alter the default form element focus navigation sequence.

So if you've got:

text input A

text input B

submit button C

by using the tab key you navigate through A->B->C. Tabindex allows you to change that flow.

Dynamic Web Module 3.0 -- 3.1

If you want to use version 3.1 you need to use the following schema:


Note that 3.0 and 3.1 are different: in 3.1 there's no Sun mentioned, so simply changing 3_0.xsd to 3_1.xsd won't work.

This is how it should look like:

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi=""
         version="3.1" xmlns="">


Also, make sure you're depending on the latest versions in your pom.xml. That is,




Finally, you should compile with Java 7 or 8:


What are naming conventions for MongoDB?

Until we get SERVER-863 keeping the field names as short as possible is advisable especially where you have a lot of records.

Depending on your use case, field names can have a huge impact on storage. Cant understand why this is not a higher priority for MongoDb, as this will have a positive impact on all users. If nothing else, we can start being more descriptive with our field names, without thinking twice about bandwidth & storage costs.

Please do vote.

How to use Google Translate API in my Java application?

You can use Google Translate API v2 Java. It has a core module that you can call from your Java code and also a command line interface module.

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

No, but you can install an isolated Python build (such as ActivePython) under your $HOME directory.

This approach is the fastest, and doesn't require you to compile Python yourself.

(as a bonus, you also get to use ActiveState's binary package manager)

How to include quotes in a string

Escape them with backslashes.

"I want to learn \"C#\""

pip3: command not found but python3-pip is already installed


locate pip3

it should give you a list of results like this


go to /usr/local/bin to make a symbolic link to where your pip3 is located

ln -s /<path>/pip3.x /usr/local/bin/pip3

Calling Java from Python

Through my own experience trying to run some java code from within python i a manner similar to how python code runs within java code in python, I was unable to a find a straight forward methodology.

My solution to my problem was by running this java code as beanshell scripts by calling the beanshell interpreter as a shell commnad from within my python code after editing the java code in a temporary file with the appropriate packages and variables.

If what I am talking about is helpful in any manner, I am glad to help you sharing more details of my solutions.

Get refresh token google api

It is access_type=offline that you want.

This will return the refresh token the first time the user authorises the app. Subsequent calls do not force you to re-approve the app (approval_prompt=force).

See further detail:

pip install fails with "connection error: [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:598)"

In my case it was due to SSL certificate being signed by internal CA of my company. Using workarounds like pip --cert did not help, but the following package did:

pip install pip_system_certs


This package patches pip and requests at runtime to use certificates from the default system store (rather than the bundled certs ca).

This will allow pip to verify tls/ssl connections to servers who’s cert is trusted by your system install.

"Exception has been thrown by the target of an invocation" error (mscorlib)

Encounter the same error when tried to connect to SQLServer2017 through Management Studio 2014

enter image description here

The reason was backward compatibility

So I just downloaded the Management Studio 2017 and tried to connect to SQLServer2017.

Problem Solve!!

How to turn off page breaks in Google Docs?

I also rarely want to print my google docs, and the breaks annoyed me as well.

I installed the Page Sizer add-on from the add-ons menu within google docs, and made the page really long.

The page settings work globally. So your collaborators will also enjoy a page page-break-free experience in google docs, unlike the style-bot solution.

All libraries must use the exact same version specification

just add this :

compile ''

Updated for new SDK versions

compile ''

How can I extract audio from video with ffmpeg?

To extract the audio stream without re-encoding:

ffmpeg -i input-video.avi -vn -acodec copy output-audio.aac
  • -vn is no video.
  • -acodec copy says use the same audio stream that's already in there.

Read the output to see what codec it is, to set the right filename extension.

Print out the values of a (Mat) matrix in OpenCV C++

See the first answer to Accessing a matrix element in the "Mat" object (not the CvMat object) in OpenCV C++
Then just loop over all the elements in cout <<<double>(0,0); rather than just 0,0

Or better still with the C++ interface:

cv::Mat M;
cout << "M = " << endl << " "  << M << endl << endl;

Debugging with command-line parameters in Visual Studio

Right click on the project in the Solution window of Visual Studio, select "Debugging" (on the left side), and enter the arguments into the field "Command Arguments":

Enter image description here

Using ng-click vs bind within link function of Angular Directive

Shouldn't it simply be:

<button ng-click="clickingCallback()">Click me<button>

Why do you want to write a new directive just to map your click event to a callback on your scope ? ng-click already does that for you.

How to determine equality for two JavaScript objects?

you can use _.isEqual(obj1, obj2) from the underscore.js library.

Here is an example:

var stooge = {name: 'moe', luckyNumbers: [13, 27, 34]};
var clone  = {name: 'moe', luckyNumbers: [13, 27, 34]};
stooge == clone;
=> false
_.isEqual(stooge, clone);
=> true

See the official documentation from here:

Import CSV to SQLite

Here's how I did it.

  • Make/Convert csv file to be seperated by tabs (\t) AND not enclosed by any quotes (sqlite interprets quotes literally - says old docs)
  • Enter the sqlite shell of the db to which the data needs to be added

    sqlite> .separator "\t" ---IMPORTANT! should be in double quotes sqlite> .import afile.csv tablename-to-import-to

Transitions on the CSS display property

I found better way for this issue, you can use CSS Animation and make your awesome effect for showing items.

.item {
     display: none;

.item:hover {
     display: block;
     animation: fade_in_show 0.5s

@keyframes fade_in_show {
     0% {
          opacity: 0;
          transform: scale(0)

     100% {
          opacity: 1;
          transform: scale(1)

JavaFX Location is not set error message

The answer below by CsPeitch and others is on the right track. Just make sure that the fxml file is being copied over to your class output target, or the runtime will not see it. Check the generated class file directory and see if the fxml is there

How to delete specific characters from a string in Ruby?

If you just want to remove the first two characters and the last two, then you can use negative indexes on the string:

s = "((String1))"
s = s[2...-2]
p s # => "String1"

If you want to remove all parentheses from the string you can use the delete method on the string class:

s = "((String1))"
s.delete! '()'
p s #  => "String1"

Read text file into string. C++ ifstream

To read a whole line from a file into a string, use std::getline like so:

 std::ifstream file("my_file");
 std::string temp;
 std::getline(file, temp);

You can do this in a loop to until the end of the file like so:

 std::ifstream file("my_file");
 std::string temp;
 while(std::getline(file, temp)) {
      //Do with temp


HTML <input type='file'> File Selection Event

Though it is an old question, it is still a valid one.

Expected behavior:

  • Show selected file name after upload.
  • Do not do anything if the user clicks Cancel.
  • Show the file name even when the user selects the same file.

Code with a demonstration:

<!DOCTYPE html>

  <title>File upload event</title>

  <form action="" method="POST" enctype="multipart/form-data">
    <input type="file" name="userFile" id="userFile"><br>
    <input type="submit" name="upload_btn" value="upload">
  <script type="text/javascript">
    document.getElementById("userFile").onchange = function(e) {
      this.value = null;



  • The onchange event handler is used to handle any change in file selection event.
  • The onchange event is triggered only when the value of an element is changed. So, when we select the same file using the input field the event will not be triggered. To overcome this, I set this.value = null; at the end of the onchange event function. It sets the file path of the selected file to null. Thus, the onchange event is triggered even at the time of the same file selection.

How to convert a String into an array of Strings containing one character each

If by array of String you mean array of char:

public class Test
    public static void main(String[] args)
        String test = "aabbab ";
        char[] t = test.toCharArray();

        for(char c : t)

        System.out.println("The end!");    

If not, the String.split() function could transform a String into an array of String

See those String.split examples

/* String to split. */
String str = "one-two-three";
String[] temp;

/* delimiter */
String delimiter = "-";
/* given string will be split by the argument delimiter provided. */
temp = str.split(delimiter);
/* print substrings */
for(int i =0; i < temp.length ; i++)

The input.split("(?!^)") proposed by Joachim in his answer is based on:

  • a '?!' zero-width negative lookahead (see Lookaround)
  • the caret '^' as an Anchor to match the start of the string the regex pattern is applied to

Any character which is not the first will be split. An empty string will not be split but return an empty array.

html "data-" attribute as javascript parameter

The short answer is that the syntax is this.dataset.whatever.

Your code should look like this:

<div data-uid="aaa" data-name="bbb" data-value="ccc"
    onclick="fun(this.dataset.uid,, this.dataset.value)">

Another important note: Javascript will always strip out hyphens and make the data attributes camelCase, regardless of whatever capitalization you use. data-camelCase will become this.dataset.camelcase and data-Camel-case will become this.dataset.camelCase.

jQuery (after v1.5 and later) always uses lowercase, regardless of your capitalization.

So when referencing your data attributes using this method, remember the camelCase:

<div data-this-is-wild="yes, it's true"

Also, you don't need to use commas to separate attributes.

Sending cookies with postman

You should enable your interceptor extension man manually, it locate in the top-right of your postman window. There are several buttons, find the interceptor button and enable it, then you can send cookies after set Cookie field in your request headers.

C++11 rvalues and move semantics confusion (return statement)

None of those will do any extra copying. Even if RVO isn't used, the new standard says that move construction is preferred to copy when doing returns I believe.

I do believe that your second example causes undefined behavior though because you're returning a reference to a local variable.

Returning JSON response from Servlet to Javascript/JSP page

I used JSONObject as shown below in Servlet.

    JSONObject jsonReturn = new JSONObject();

    NhAdminTree = AdminTasks.GetNeighborhoodTreeForNhAdministrator( connection, bwcon, userName);

    map = new HashMap<String, String>();
    map.put("Status", "Success");
    map.put("FailureReason", "None");
    map.put("DataElements", "2");

    jsonReturn = new JSONObject();
    jsonReturn.accumulate("Header", map);

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

    jsonReturn.accumulate("Elements", list);

The Servlet returns this JSON object as shown below:


This Servlet is called from Browser using AngularJs as below

$scope.GetNeighborhoodTreeUsingPost = function(){
    alert("Clicked GetNeighborhoodTreeUsingPost : " + $scope.userName );


        method: 'POST',
        url : 'http://localhost:8080/EPortal/xlEPortalService',
        headers: {
           'Content-Type': 'application/json'
        data : {
            'action': 64,
            'userName' : $scope.userName
    }).success(function(data, status, headers, config){
        alert("DATA.header.status : " + data.Header.Status);
        alert("DATA.header.FailureReason : " + data.Header.FailureReason);
        alert("DATA.header.DataElements : " + data.Header.DataElements);
        alert("DATA.elements : " + data.Elements);

    }).error(function(data, status, headers, config) {
        alert(data + " : " + status + " : " + headers + " : " + config);


This code worked and it is showing correct data in alert dialog box:

Data.header.status : Success

Data.header.FailureReason : None

Data.header.DetailElements : 2

Data.Elements : Coma seperated string values i.e. NhAdminTree, userName

How do I capture the output of a script if it is being ran by the task scheduler?

You can have a debug.cmd that calls yourscript.cmd

yourscript.cmd > logall.txt

you schedule debug.cmd instead of yourscript.cmd

How to run multiple DOS commands in parallel?

I suggest you to see "How do I run a bat file in the background from another bat file?"

Also, good answer (of using start command) was given in "Parallel execution of shell processes" question page here;

But my recommendation is to use PowerShell. I believe it will perfectly suit your needs.

use "netsh wlan set hostednetwork ..." to create a wifi hotspot and the authentication can't work correctly

For me, running the ad-hoc network on Windows 8.1, it was two things:

  • I had to set a static IP on my Android (under Advanced Options under where you type the Wifi password)
  • I had to use a password 8 characters long

Any IP will allow you to connect, but if you want internet access the static IP should match the subnet from the shared internet connection.

I'm not sure why I couldn't get a longer password to work, but it's worth a try. Maybe a more knowledgeable person could fill us in.

Execute jar file with multiple classpath libraries from command prompt

Using java 1.7, on UNIX -

java -cp myjar.jar:lib/*:. mypackage.MyClass

On Windows you need to use ';' instead of ':' -

java -cp myjar.jar;lib/*;. mypackage.MyClass

Using Linq to get the last N elements of a collection?

If you are dealing with a collection with a key (e.g. entries from a database) a quick (i.e. faster than the selected answer) solution would be

collection.OrderByDescending(c => c.Key).Take(3).OrderBy(c => c.Key);

How do I assign ls to an array in Linux Bash?

Whenever possible, you should avoid parsing the output of ls (see Greg's wiki on the subject). Basically, the output of ls will be ambiguous if there are funny characters in any of the filenames. It's also usually a waste of time. In this case, when you execute ls -d */, what happens is that the shell expands */ to a list of subdirectories (which is already exactly what you want), passes that list as arguments to ls -d, which looks at each one, says "yep, that's a directory all right" and prints it (in an inconsistent and sometimes ambiguous format). The ls command isn't doing anything useful!

Well, ok, it is doing one thing that's useful: if there are no subdirectories, */ will get left as is, ls will look for a subdirectory named "*", not find it, print an error message that it doesn't exist (to stderr), and not print the "*/" (to stdout).

The cleaner way to make an array of subdirectory names is to use the glob (*/) without passing it to ls. But in order to avoid putting "*/" in the array if there are no actual subdirectories, you should set nullglob first (again, see Greg's wiki):

shopt -s nullglob
shopt -u nullglob # Turn off nullglob to make sure it doesn't interfere with anything later
echo "${array[@]}"  # Note double-quotes to avoid extra parsing of funny characters in filenames

If you want to print an error message if there are no subdirectories, you're better off doing it yourself:

if (( ${#array[@]} == 0 )); then
    echo "No subdirectories found" >&2

Passing ArrayList through Intent

Suppose you need to pass an arraylist of following class from current activity to next activity // class of the objects those in the arraylist // remember to implement the class from Serializable interface // Serializable means it converts the object into stream of bytes and helps to transfer that object

public class Question implements Serializable {

in your current activity you probably have an ArrayList as follows

ArrayList<Question> qsList = new ArrayList<>();
qsList.add(new Question(1));
qsList.add(new Question(2));
qsList.add(new Question(3));

// intialize Bundle instance
Bundle b = new Bundle();
// putting questions list into the bundle .. as key value pair.
// so you can retrieve the arrayList with this key
b.putSerializable("questions", (Serializable) qsList);
Intent i = new Intent(CurrentActivity.this, NextActivity.class);

in order to get the arraylist within the next activity

//get the bundle
Bundle b = getIntent().getExtras();
//getting the arraylist from the key
ArrayList<Question> q = (ArrayList<Question>) b.getSerializable("questions");

Command-line svn for Windows?

VisualSVN for Windows has a command-line-only executable (as well Visual Studio plugins). See

It is completely portable, so no installation is necessary.

C# list.Orderby descending

look it this piece of code from my project

I'm trying to re-order the list based on a property inside my model,

 allEmployees = new List<Employee>(allEmployees.OrderByDescending(employee => employee.Name));

but I faced a problem when a small and capital letters exist, so to solve it, I used the string comparer.

allEmployees.OrderBy(employee => employee.Name,StringComparer.CurrentCultureIgnoreCase)

What is the string length of a GUID?

Binary strings store raw-byte data, whilst character strings store text. Use binary data when storing hexi-decimal values such as SID, GUID and so on. The uniqueidentifier data type contains a globally unique identifier, or GUID. This value is derived by using the NEWID() function to return a value that is unique to all objects. It's stored as a binary value but it is displayed as a character string.

Here is an example.

USE AdventureWorks2008R2;
CREATE TABLE MyCcustomerTable
    user_login   varbinary(85) DEFAULT SUSER_SID()
    ,data_value   varbinary(1)

INSERT MyCustomerTable (data_value)
    VALUES (0x4F);

Applies to: SQL Server The following example creates the cust table with a uniqueidentifier data type, and uses NEWID to fill the table with a default value. In assigning the default value of NEWID(), each new and existing row has a unique value for the CustomerID column.

-- Creating a table using NEWID for uniqueidentifier data type.  
 CustomerID uniqueidentifier NOT NULL  
   DEFAULT newid(),  
 Company varchar(30) NOT NULL,  
 ContactName varchar(60) NOT NULL,   
 Address varchar(30) NOT NULL,   
 City varchar(30) NOT NULL,  
 StateProvince varchar(10) NULL,  
 PostalCode varchar(10) NOT NULL,   
 CountryRegion varchar(20) NOT NULL,   
 Telephone varchar(15) NOT NULL,  
 Fax varchar(15) NULL  
-- Inserting 5 rows into cust table.  
INSERT cust  
(CustomerID, Company, ContactName, Address, City, StateProvince,   
 PostalCode, CountryRegion, Telephone, Fax)  
 (NEWID(), 'Wartian Herkku', 'Pirkko Koskitalo', 'Torikatu 38', 'Oulu', NULL,  
 '90110', 'Finland', '981-443655', '981-443655')  
,(NEWID(), 'Wellington Importadora', 'Paula Parente', 'Rua do Mercado, 12', 'Resende', 'SP',  
 '08737-363', 'Brasil', '(14) 555-8122', '')  
,(NEWID(), 'Cactus Comidas para Ilevar', 'Patricio Simpson', 'Cerrito 333', 'Buenos Aires', NULL,   
 '1010', 'Argentina', '(1) 135-5555', '(1) 135-4892')  
,(NEWID(), 'Ernst Handel', 'Roland Mendel', 'Kirchgasse 6', 'Graz', NULL,  
 '8010', 'Austria', '7675-3425', '7675-3426')  
,(NEWID(), 'Maison Dewey', 'Catherine Dewey', 'Rue Joseph-Bens 532', 'Bruxelles', NULL,  
 'B-1180', 'Belgium', '(02) 201 24 67', '(02) 201 24 68');  

C# - How to add an Excel Worksheet programmatically - Office XP / 2003

You need to add a COM reference in your project to the "Microsoft Excel 11.0 Object Library" - or whatever version is appropriate.

This code works for me:

private void AddWorksheetToExcelWorkbook(string fullFilename,string worksheetName)
    Microsoft.Office.Interop.Excel.Application xlApp = null;
    Workbook xlWorkbook = null;
    Sheets xlSheets = null;
    Worksheet xlNewSheet = null;

    try {
        xlApp = new Microsoft.Office.Interop.Excel.Application();

        if (xlApp == null)

        // Uncomment the line below if you want to see what's happening in Excel
        // xlApp.Visible = true;

        xlWorkbook = xlApp.Workbooks.Open(fullFilename, 0, false, 5, "", "",
                false, XlPlatform.xlWindows, "",
                true, false, 0, true, false, false);

        xlSheets = xlWorkbook.Sheets as Sheets;

        // The first argument below inserts the new worksheet as the first one
        xlNewSheet = (Worksheet)xlSheets.Add(xlSheets[1], Type.Missing, Type.Missing, Type.Missing);
        xlNewSheet.Name = worksheetName;

    finally {
        xlApp = null;

Note that you want to be very careful about properly cleaning up and releasing your COM object references. Included in that StackOverflow question is a useful rule of thumb: "Never use 2 dots with COM objects". In your code; you're going to have real trouble with that. My demo code above does NOT properly clean up the Excel app, but it's a start!

Some other links that I found useful when looking into this question:

According to MSDN

To use COM interop, you must have administrator or Power User security permissions.

Hope that helps.

XAMPP - Apache could not start - Attempting to start Apache service

Solution for my particular scenario (It had been working a couple days before getting borked):

Port 80 was not the problem, but something I had done while messing around with Services and Startup.

  1. Type msconfig on Windows' Start menu
  2. Click System Configuration

Screenshot for System Configuration

  1. In the Services tab, search for Apache24 (Click "Hide all Microsoft services" in the checkbox at the bottom of the window to make it easier to find)
  2. If its checkbox isn't checked, check it

If it was already checked, then this guide isn't going to help. However if it is:

  1. Click OK, your PC will have to restart
  2. Try once again! In my case Apache was already running once I opened Xampp

Disabling swap files creation in vim

Set the following variables in .vimrc or /etc/vimrc to make vim put swap, backup and undo files in a special location instead of the working directory of the file being edited:

set backupdir=~/.vim/backup//
set directory=~/.vim/swap//
set undodir=~/.vim/undo//

Using double trailing slashes in the path tells vim to enable a feature where it avoids name collisions. For example, if you edit a file in one location and another file in another location and both files have the same name, you don't want a name collision to occur in ~/.vim/swap/. If you specify ~/.vim/swap// with two trailing slashes vim will create swap files using the whole path of the files being edited to avoid collisions (slashes in the file's path will be replaced by percent symbol %).

For example, if you edit /path/one/foobar.txt and /path/two/foobar.txt, then you will see two swap files in ~/.vim/swap/ that are named %path%one%foobar.txt and %path%two%foobar.txt, respectively.

Use string.Contains() with switch()

Faced with this issue when determining an environment, I came up with the following one-liner:

string ActiveEnvironment = localEnv.Contains("LIVE") ? "LIVE" : (localEnv.Contains("TEST") ? "TEST" : (localEnv.Contains("LOCAL") ? "LOCAL" : null));

That way, if it can't find anything in the provided string that matches the "switch" conditions, it gives up and returns null. This could easily be amended to return a different value.

It's not strictly a switch, more a cascading if statement but it's neat and it worked.

PHP foreach loop through multidimensional array

$last = count($arr_nav) - 1;

foreach ($arr_nav as $i => $row)
    $isFirst = ($i == 0);
    $isLast = ($i == $last);

    echo ... $row['name'] ... $row['url'] ...;

PowerShell script to check the status of a URL

Below is the PowerShell code that I use for basic web URL testing. It includes the ability to accept invalid certs and get detailed information about the results of checking the certificate.

$CertificateValidatorClass = @'
using System;
using System.Collections.Concurrent;
using System.Net;
using System.Security.Cryptography;
using System.Text;

namespace CertificateValidation
    public class CertificateValidationResult
        public string Subject { get; internal set; }
        public string Thumbprint { get; internal set; }
        public DateTime Expiration { get; internal set; }
        public DateTime ValidationTime { get; internal set; }
        public bool IsValid { get; internal set; }
        public bool Accepted { get; internal set; }
        public string Message { get; internal set; }

        public CertificateValidationResult()
            ValidationTime = DateTime.UtcNow;

    public static class CertificateValidator
        private static ConcurrentStack<CertificateValidationResult> certificateValidationResults = new ConcurrentStack<CertificateValidationResult>();

        public static CertificateValidationResult[] CertificateValidationResults
                return certificateValidationResults.ToArray();

        public static CertificateValidationResult LastCertificateValidationResult
                CertificateValidationResult lastCertificateValidationResult = null;
                certificateValidationResults.TryPeek(out lastCertificateValidationResult);

                return lastCertificateValidationResult;

        public static bool ServicePointManager_ServerCertificateValidationCallback(object sender, System.Security.Cryptography.X509Certificates.X509Certificate certificate, System.Security.Cryptography.X509Certificates.X509Chain chain, System.Net.Security.SslPolicyErrors sslPolicyErrors)
            StringBuilder certificateValidationMessage = new StringBuilder();
            bool allowCertificate = true;

            if (sslPolicyErrors != System.Net.Security.SslPolicyErrors.None)
                if ((sslPolicyErrors & System.Net.Security.SslPolicyErrors.RemoteCertificateNameMismatch) == System.Net.Security.SslPolicyErrors.RemoteCertificateNameMismatch)
                    certificateValidationMessage.AppendFormat("The remote certificate name does not match.\r\n", certificate.Subject);

                if ((sslPolicyErrors & System.Net.Security.SslPolicyErrors.RemoteCertificateChainErrors) == System.Net.Security.SslPolicyErrors.RemoteCertificateChainErrors)
                    certificateValidationMessage.AppendLine("The certificate chain has the following errors:");
                    foreach (System.Security.Cryptography.X509Certificates.X509ChainStatus chainStatus in chain.ChainStatus)
                        certificateValidationMessage.AppendFormat("\t{0}", chainStatus.StatusInformation);

                        if (chainStatus.Status == System.Security.Cryptography.X509Certificates.X509ChainStatusFlags.Revoked)
                            allowCertificate = false;

                if ((sslPolicyErrors & System.Net.Security.SslPolicyErrors.RemoteCertificateNotAvailable) == System.Net.Security.SslPolicyErrors.RemoteCertificateNotAvailable)
                    certificateValidationMessage.AppendLine("The remote certificate was not available.");
                    allowCertificate = false;

                certificateValidationMessage.AppendLine("The remote certificate is valid.");

            CertificateValidationResult certificateValidationResult = new CertificateValidationResult
                    Subject = certificate.Subject,
                    Thumbprint = certificate.GetCertHashString(),
                    Expiration = DateTime.Parse(certificate.GetExpirationDateString()),
                    IsValid = (sslPolicyErrors == System.Net.Security.SslPolicyErrors.None),
                    Accepted = allowCertificate,
                    Message = certificateValidationMessage.ToString()

            return allowCertificate;

        public static void SetDebugCertificateValidation()
            ServicePointManager.ServerCertificateValidationCallback = ServicePointManager_ServerCertificateValidationCallback;

        public static void SetDefaultCertificateValidation()
            ServicePointManager.ServerCertificateValidationCallback = null;

        public static void ClearCertificateValidationResults()

function Set-CertificateValidationMode
    Sets the certificate validation mode.
    Set the certificate validation mode to one of three modes with the following behaviors:
        Default -- Performs the .NET default validation of certificates. Certificates are not checked for revocation and will be rejected if invalid.
        CheckRevocationList -- Cerftificate Revocation Lists are checked and certificate will be rejected if revoked or invalid.
        Debug -- Certificate Revocation Lists are checked and revocation will result in rejection. Invalid certificates will be accepted. Certificate validation
                 information is logged and can be retrieved from the certificate handler.
    Set-CertificateValidationMode Debug
    The mode for certificate validation.
    [CmdletBinding(SupportsShouldProcess = $false)]
        [ValidateSet('Default', 'CheckRevocationList', 'Debug')]
        [string] $Mode

        $isValidatorClassLoaded = (([System.AppDomain]::CurrentDomain.GetAssemblies() | ?{ $_.GlobalAssemblyCache -eq $false }) | ?{ $_.DefinedTypes.FullName -contains 'CertificateValidation.CertificateValidator' }) -ne $null

        if ($isValidatorClassLoaded -eq $false)
            Add-Type -TypeDefinition $CertificateValidatorClass

        switch ($Mode)
                [System.Net.ServicePointManager]::CheckCertificateRevocationList = $true
                [System.Net.ServicePointManager]::CheckCertificateRevocationList = $true
                [System.Net.ServicePointManager]::CheckCertificateRevocationList = $false

function Clear-CertificateValidationResults
    Clears the collection of certificate validation results.
    Clears the collection of certificate validation results.
    [CmdletBinding(SupportsShouldProcess = $false)]

        $isValidatorClassLoaded = (([System.AppDomain]::CurrentDomain.GetAssemblies() | ?{ $_.GlobalAssemblyCache -eq $false }) | ?{ $_.DefinedTypes.FullName -contains 'CertificateValidation.CertificateValidator' }) -ne $null

        if ($isValidatorClassLoaded -eq $false)
            Add-Type -TypeDefinition $CertificateValidatorClass

        Sleep -Milliseconds 20

function Get-CertificateValidationResults
    Gets the certificate validation results for all operations performed in the PowerShell session since the Debug cerificate validation mode was enabled.
    Gets the certificate validation results for all operations performed in the PowerShell session since the Debug certificate validation mode was enabled in reverse chronological order.
    [CmdletBinding(SupportsShouldProcess = $false)]

        $isValidatorClassLoaded = (([System.AppDomain]::CurrentDomain.GetAssemblies() | ?{ $_.GlobalAssemblyCache -eq $false }) | ?{ $_.DefinedTypes.FullName -contains 'CertificateValidation.CertificateValidator' }) -ne $null

        if ($isValidatorClassLoaded -eq $false)
            Add-Type -TypeDefinition $CertificateValidatorClass

        return [CertificateValidation.CertificateValidator]::CertificateValidationResults

function Test-WebUrl
    Tests and reports information about the provided web URL.
    Tests a web URL and reports the time taken to get and process the request and response, the HTTP status, and the error message if an error occurred.
    Test-WebUrl ''
    '' | Test-WebUrl
    .PARAMETER HostName
    The Hostname to add to the back connection hostnames list.
    .PARAMETER UseDefaultCredentials
    If present the default Windows credential will be used to attempt to authenticate to the URL; otherwise, no credentials will be presented.
        [Parameter(Mandatory = $true, ValueFromPipeline = $true)]
        [Uri] $Url,
        [Microsoft.PowerShell.Commands.WebRequestMethod] $Method = 'Get',
        [switch] $UseDefaultCredentials

        [bool] $succeeded = $false
        [string] $statusCode = $null
        [string] $statusDescription = $null
        [string] $message = $null
        [int] $bytesReceived = 0
        [Timespan] $timeTaken = [Timespan]::Zero 

        $timeTaken = Measure-Command `
                    [Microsoft.PowerShell.Commands.HtmlWebResponseObject] $response = Invoke-WebRequest -UseDefaultCredentials:$UseDefaultCredentials -Method $Method -Uri $Url
                    $succeeded = $true
                    $statusCode = $response.StatusCode.ToString('D')
                    $statusDescription = $response.StatusDescription
                    $bytesReceived = $response.RawContent.Length

                    Write-Verbose "$($Url.ToString()): $($statusCode) $($statusDescription) $($message)"
                catch [System.Net.WebException]
                    $message = $Error[0].Exception.Message
                    [System.Net.HttpWebResponse] $exceptionResponse = $Error[0].Exception.GetBaseException().Response

                    if ($exceptionResponse -ne $null)
                        $statusCode = $exceptionResponse.StatusCode.ToString('D')
                        $statusDescription = $exceptionResponse.StatusDescription
                        $bytesReceived = $exceptionResponse.ContentLength

                        if ($statusCode -in '401', '403', '404')
                            $succeeded = $true
                        Write-Warning "$($Url.ToString()): $($message)"

        return [PSCustomObject] @{ Url = $Url; Succeeded = $succeeded; BytesReceived = $bytesReceived; TimeTaken = $timeTaken.TotalMilliseconds; StatusCode = $statusCode; StatusDescription = $statusDescription; Message = $message; }

Set-CertificateValidationMode Debug

Write-Host 'Testing web sites:'
'', '', '', '', '', '', '' | Test-WebUrl | ft -AutoSize

Write-Host 'Certificate validation results (most recent first):'
Get-CertificateValidationResults | ft -AutoSize

How can I loop over entries in JSON?

Try this :

import urllib, urllib2, json
url = ''
request = urllib2.Request(url)
request.add_header('User-Agent','Mozilla/4.0 (compatible; MSIE 5.5; Windows NT)')
response = urllib2.urlopen(request)
json_object = json.load(response)
#print json_object['results']
if json_object['team'] == []:
    print 'No Data!'
    for rows in json_object['team']:
        print 'Team ID:' + rows['team_id']
        print 'Team Name:' + rows['team_name']
        print 'Team URL:' + rows['team_icon_url']

npm start error with create-react-app

I fix this using this following command:

npm install -g react-scripts

DateTime and CultureInfo

Use CultureInfo class to change your culture info.

var dutchCultureInfo = CultureInfo.CreateSpecificCulture("nl-NL");
var date1 = DateTime.ParseExact(date, "dd.MM.yyyy HH:mm:ss", dutchCultureInfo);

MongoDB: How to update multiple documents with a single command?

MongoDB will find only one matching document which matches the query criteria when you are issuing an update command, whichever document matches first happens to be get updated, even if there are more documents which matches the criteria will get ignored.

so to overcome this we can specify "MULTI" option in your update statement, meaning update all those documnets which matches the query criteria. scan for all the documnets in collection finding those which matches the criteria and update :

db.test.update({"foo":"bar"},{"$set":{"test":"success!"}}, {multi:true} )

Python: list of lists

I came here because I'm new with python and lazy so I was searching an example to create a list of 2 lists, after a while a realized the topic here could be wrong... this is a code to create a list of lists:

listoflists = []
for i in range(0,2):
    sublist = []
    for j in range(0,10)
print listoflists

this the output [ [(0, 0), (0, 1), (0, 2), (0, 3), (0, 4), (0, 5), (0, 6), (0, 7), (0, 8), (0, 9)], [(1, 0), (1, 1), (1, 2), (1, 3), (1, 4), (1, 5), (1, 6), (1, 7), (1, 8), (1, 9)] ]

The problem with your code seems to be you are creating a tuple with your list and you get the reference to the list instead of a copy. That I guess should fall under a tuple topic...

ORA-00904: invalid identifier

In my case, this error occurred, due to lack of existence of column name in the table.

When i executed "describe tablename" , i was not able to find the column specified in the mapping hbm file.

After altering the table, it worked fine.

Merging Cells in Excel using C#

You can use Microsoft.Office.Interop.Excel:

worksheet.Range[worksheet.Cells[rowNum, columnNum], worksheet.Cells[rowNum, columnNum]].Merge();

You can also use NPOI:

var cellsTomerge = new NPOI.SS.Util.CellRangeAddress(firstrow, lastrow, firstcol, lastcol);

Static link of shared library function in gcc

If you want to link, say, libapplejuice statically, but not, say, liborangejuice, you can link like this:

gcc object1.o object2.o -Wl,-Bstatic -lapplejuice -Wl,-Bdynamic -lorangejuice -o binary

There's a caveat -- if liborangejuice uses libapplejuice, then libapplejuice will be dynamically linked too.

You'll have to link liborangejuice statically alongside with libapplejuice to get libapplejuice static.

And don't forget to keep -Wl,-Bdynamic else you'll end up linking everything static, including libc (which isn't a good thing to do).

VS2010 How to include files in project, to copy them to build output directory automatically during build or publish

I only have the need to push files during a build, so I just added a Post-build Event Command Line entry like this:

Copy /Y "$(SolutionDir)Third Party\SomeLibrary\*" "$(TargetDir)"

You can set this by right-clicking your Project in the Solution Explorer, then Properties > Build Events

How to read from a text file using VBScript?

Use first the method OpenTextFile, and then...

either read the file at once with the method ReadAll:

Set file = fso.OpenTextFile("C:\test.txt", 1)
content = file.ReadAll

or line by line with the method ReadLine:

Set dict = CreateObject("Scripting.Dictionary")
Set file = fso.OpenTextFile ("c:\test.txt", 1)
row = 0
Do Until file.AtEndOfStream
  line = file.Readline
  dict.Add row, line
  row = row + 1


'Loop over it
For Each line in dict.Items
  WScript.Echo line

How to validate domain credentials?

C# in .NET 3.5 using System.DirectoryServices.AccountManagement.

 bool valid = false;
 using (PrincipalContext context = new PrincipalContext(ContextType.Domain))
     valid = context.ValidateCredentials( username, password );

This will validate against the current domain. Check out the parameterized PrincipalContext constructor for other options.

Synchronous Requests in Node.js

You can do something exactly similar with the request library, but this is sync using const https = require('https'); or const http = require('http');, which should come with node.

Here is an example,

const https = require('https');

const http_get1 = {
    host : '',
    port : '443',
    path : '/youtube/v3/search?arg=1',
    method : 'GET',
    headers : {
        'Content-Type' : 'application/json'

const http_get2 = {
host : '',
    port : '443',
    path : '/youtube/v3/search?arg=2',
    method : 'GET',
    headers : {
        'Content-Type' : 'application/json'

let data1 = '';
let data2 = '';

function master() {





const req1 = https.request(http_get1, (res) => {

    res.on('data', (chunk) => {
        data1 += chunk;

    res.on('end', () => {

const req2 = https.request(http_get2, (res) => {

    res.on('data', (chunk) => {
        data2 += chunk;

    res.on('end', () => {


How to sort an array of objects by multiple fields?

Sorting on two date fields and a numeric field example:

var generic_date =  new Date(2070, 1, 1);
checkDate = function(date) {
  return Date.parse(date) ? new Date(date): generic_date;

function sortData() {  
    var deltaEnd = checkDate(b.end) - checkDate(a.end);
    if(deltaEnd) return deltaEnd;

    var deltaRank = a.rank - b.rank;
    if (deltaRank) return deltaRank;

    var deltaStart = checkDate(b.start) - checkDate(a.start);
    if(deltaStart) return deltaStart;

    return 0;

Does uninstalling a package with "pip" also remove the dependent packages?

You may have a try for It will remove package with its all dependencies.

Typescript ReferenceError: exports is not defined

For some ASP.NET projects import and export may not be used at all in your Typescripts.

The question's error showed up when I attempted to do so and I only discovered later that I just needed to add the generated JS script to the View like so:

<script src="~/scripts/js/[GENERATED_FILE].Index.js" asp-append-version="true"></script>

Python 3 ImportError: No module named 'ConfigParser'

Try this solution which worked fine for me.

Basically it's to reinstall/upgrade to latest version of mysql from brew, and then installing mysqlclient or MySQL-Python from global pip3 instead of virtualenv pip3.

Then accessing the virtualenv and successfully install mysqlclient or MySQL-Python.

Permission denied on accessing host directory in Docker

I had a similar issue, mine was caused by a mismatch between the UID of the host and the UID of the container's user. The fix was to pass the UID of the user as an argument to the docker build and create the container's user with the same UID.

In the DockerFile:

ARG UID=1000
ENV USER="ubuntu"
RUN useradd -u $UID -ms /bin/bash $USER

In the build step:

docker build <path/to/Dockerfile> -t <tag/name> --build-arg UID=$UID

After that, running the container and commands as per the OP gave me the expected result.

RegExp in TypeScript

In typescript, the declaration is something like this:

const regex : RegExp = /.+\*.+/;

using RegExp constructor:

const regex = new RegExp('.+\\*.+');

<modules runAllManagedModulesForAllRequests="true" /> Meaning

Modules Preconditions:

The IIS core engine uses preconditions to determine when to enable a particular module. Performance reasons, for example, might determine that you only want to execute managed modules for requests that also go to a managed handler. The precondition in the following example (precondition="managedHandler") only enables the forms authentication module for requests that are also handled by a managed handler, such as requests to .aspx or .asmx files:

<add name="FormsAuthentication" type="System.Web.Security.FormsAuthenticationModule" preCondition="managedHandler" />

If you remove the attribute precondition="managedHandler", Forms Authentication also applies to content that is not served by managed handlers, such as .html, .jpg, .doc, but also for classic ASP (.asp) or PHP (.php) extensions. See "How to Take Advantage of IIS Integrated Pipeline" for an example of enabling ASP.NET modules to run for all content.

You can also use a shortcut to enable all managed (ASP.NET) modules to run for all requests in your application, regardless of the "managedHandler" precondition.

To enable all managed modules to run for all requests without configuring each module entry to remove the "managedHandler" precondition, use the runAllManagedModulesForAllRequests property in the <modules> section:

<modules runAllManagedModulesForAllRequests="true" />    

When you use this property, the "managedHandler" precondition has no effect and all managed modules run for all requests.

Copied from IIS Modules Overview: Preconditions

How do I make a batch file terminate upon encountering an error?

Here is a polyglot program for BASH and Windows CMD that runs a series of commands and quits out if any of them fail:

#!/bin/bash 2> nul

:; set -o errexit
:; function goto() { return $?; }

command 1 || goto :error

command 2 || goto :error

command 3 || goto :error

:; exit 0
exit /b 0

exit /b %errorlevel%

I have used this type of thing in the past for a multiple platform continuous integration script.

Shadow Effect for a Text in Android?

put these in values/colors.xml

    <color name="light_font">#FBFBFB</color>
    <color name="grey_font">#ff9e9e9e</color>
    <color name="text_shadow">#7F000000</color>
    <color name="text_shadow_white">#FFFFFF</color>

Then in your layout xml here are some example TextView's

Example of Floating text on Light with Dark shadow

<TextView android:id="@+id/txt_example1"
                  android:shadowRadius="2" />

enter image description here

Example of Etched text on Light with Dark shadow

<TextView android:id="@+id/txt_example2"
                android:shadowRadius="1" />

enter image description here

Example of Crisp text on Light with Dark shadow

<TextView android:id="@+id/txt_example3"
                android:shadowRadius="1" />

enter image description here

Notice the positive and negative values... I suggest to play around with the colors/values yourself but ultimately you can adjust these settings to get the effect your looking for.

Read contents of a local file into a variable in Rails

Answering my own question here... turns out it's a Windows only quirk that happens when reading binary files (in my case a JPEG) that requires an additional flag in the open or function call. I revised it to open("/path/to/file", 'rb') {|io| a = a +} and all was fine.

Set output of a command as a variable (with pipes)

In a batch file I usually create a file in the temp directory and append output from a program, then I call it with a variable-name to set that variable. Like this:

:: Create a set_var.cmd file containing: set %1=
set /p="set %%1="<nul>"%temp%\set_var.cmd"

:: Append output from a command
ipconfig | find "IPv4" >> "%temp%\set_var.cmd"
call "%temp%\set_var.cmd" IPAddress
echo %IPAddress%

Cannot find "Package Explorer" view in Eclipse

Not all view are listed directly in every perspective ... choose:

Window->Show View->Other...->Java->Package Explorer

@Cacheable key on multiple method arguments

Use this

@Cacheable(value="bookCache", key="#isbn + '_' + #checkWarehouse + '_' + #includeUsed")

How to refer to relative paths of resources when working with a code repository

I got stumped here a bit. Wanted to package some resource files into a wheel file and access them. Did the packaging using manifest file, but pip install was not installing it unless it was a sub directory. Hoping these sceen shots will help

+-- cnn_client
¦   +--
¦   +--
¦   +-- resources
¦   ¦   +-- mscoco_complete_label_map.pbtxt
¦   ¦   +-- retinanet_complete_label_map.pbtxt
¦   ¦   +--
¦   +--

recursive-include cnn_client/resources *

Created a weel using standard . pip installed the wheel file. After installation checked if resources are installed. They are

ls /usr/local/lib/python2.7/dist-packages/cnn_client/resources


In to access these files. from

templates_dir = os.path.join(os.path.dirname(__file__), 'resources')
 file_path = os.path.join(templates_dir, \
        s = open(file_path, 'r').read()

And it works.

PHP: Count a stdClass object

There is nothing wrong with count() here, "trends" is the only key that is being counted in this case, you can try doing:



count($obj->trends['2009-08-21 11:05']);

Or maybe even doing:

count($obj, COUNT_RECURSIVE);

How do I merge dictionaries together in Python?

I believe that, as stated above, using d2.update(d1) is the best approach and that you can also copy d2 first if you still need it.

Although, I want to point out that dict(d1, **d2) is actually a bad way to merge dictionnaries in general since keyword arguments need to be strings, thus it will fail if you have a dict such as:

  1: 'foo',
  2: 'bar'

Replacing characters in Ant property

Or... You can also to try Your Own Task


class CustomString extends Task{

private String type, string, before, after, returnValue;

public void execute() {
    if (getType().equals("replace")) {
        replace(getString(), getBefore(), getAfter());

private void replace(String str, String a, String b){
    String results = str.replace(a, b);
    Project project = getProject();
    project.setProperty(getReturnValue(), results);

..all getter and setter..


<project name="ant-test" default="build">

<target name="build" depends="compile, run"/>

<target name="clean">
    <delete dir="build" />

<target name="compile" depends="clean">
    <mkdir dir="build/classes"/>
    <javac srcdir="src" destdir="build/classes" includeantruntime="true"/>

<target name="declare" depends="compile">
    <taskdef name="string" classname="CustomString" classpath="build/classes" />

<!-- Replacing characters in Ant property -->
<target name="run" depends="declare">
    <property name="propA" value="This is a value"/>
    <echo message="propA=${propA}" />
    <string type="replace" string="${propA}" before=" " after="_" returnvalue="propB"/>
    <echo message="propB=${propB}" />


     [echo] propA=This is a value
     [echo] propB=This_is_a_value

On logout, clear Activity history stack, preventing "back" button from opening logged-in-only Activities

The selected answer is clever and tricky. Here's how I did it:

LoginActivity is the root activity of the task, set android:noHistory="true" to it in Manifest.xml; Say you want to logout from SettingsActivity, you can do it as below:

    Intent i = new Intent(SettingsActivity.this, LoginActivity.class);
            | Intent.FLAG_ACTIVITY_NEW_TASK);

How to concatenate two layers in keras?

Adding to the above-accepted answer so that it helps those who are using tensorflow 2.0

import tensorflow as tf

# some data
c1 = tf.constant([[1, 1, 1], [2, 2, 2]], dtype=tf.float32)
c2 = tf.constant([[2, 2, 2], [3, 3, 3]], dtype=tf.float32)
c3 = tf.constant([[3, 3, 3], [4, 4, 4]], dtype=tf.float32)

# bake layers x1, x2, x3
x1 = tf.keras.layers.Dense(10)(c1)
x2 = tf.keras.layers.Dense(10)(c2)
x3 = tf.keras.layers.Dense(10)(c3)

# merged layer y1
y1 = tf.keras.layers.Concatenate(axis=1)([x1, x2])

# merged layer y2
y2 = tf.keras.layers.Concatenate(axis=1)([y1, x3])

# print info
print("x1", x1.shape, "x2", x2.shape, "x3", x3.shape)
print("y1", y1.shape)
print("y2", y2.shape)


x1 (2, 10) x2 (2, 10) x3 (2, 10)
y1 (2, 20)
y2 (2, 30)

Are 64 bit programs bigger and faster than 32 bit versions?

In addition to having more registers, 64-bit has SSE2 by default. This means that you can indeed perform some calculations in parallel. The SSE extensions had other goodies too. But I guess the main benefit is not having to check for the presence of the extensions. If it's x64, it has SSE2 available. ...If my memory serves me correctly.

Changing background color of selected item in recyclerview

in the Kotlin you can do this simply: all you need is to create a static variable like this:

companion object {
     var last_position = 0

then in your onBindViewHolder add this code:


which item is the child of recyclerView which you want to change its background after clicking on it.

Removing duplicate objects with Underscore for Javascript

You can do it in a shorthand as:

_.uniq(foo, 'a')

Angular window resize event

Here is a simple and clean solution I created so I could inject it into multiple components.


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

  providedIn: 'root'
export class ResizeService {

  constructor() {

    window.addEventListener('resize', (e) => {;


  public onResize = new Subject();


In use:

  private resizeService: ResizeService
) { 

  this.subscriptions.push(this.resizeService.onResize.subscribe(() => {
    // Do stuff


private subscriptions: Subscription[] = [];

New lines (\r\n) are not working in email body

"\n\r" produces 2 new lines while "\n","\r" & "\r\n" produce single lines if, in the Header, you use content-type: text/plain.

Beware: If you do the Following php code:

print $message.'<br><br>';
print $message;

you get the following in the Windows browser:


ab cd e f

and with content-type: text/plain you get the following in an email output;


SQL Server Management Studio, how to get execution time down to milliseconds

I was struggling with that until i found this...

Also, if you open the Properties window you may find some magical "Connection elapsed time" that may give you some execution time... Hope it helps...

How to delete an element from an array in C#

I posted my solution here.

This is a way to delete an array element without copying to another array - just in frame of the same array instance:

    public static void RemoveAt<T>(ref T[] arr, int index)
        for (int a = index; a < arr.Length - 1; a++)
            // moving elements downwards, to fill the gap at [index]
            arr[a] = arr[a + 1];
        // finally, let's decrement Array's size by one
        Array.Resize(ref arr, arr.Length - 1);

#ifdef in C#

I would recommend you using the Conditional Attribute!

Update: 3.5 years later

You can use #if like this (example copied from MSDN):

// preprocessor_if.cs
#define DEBUG
#define VC_V7
using System;
public class MyClass 
    static void Main() 
#if (DEBUG && !VC_V7)
        Console.WriteLine("DEBUG is defined");
#elif (!DEBUG && VC_V7)
        Console.WriteLine("VC_V7 is defined");
#elif (DEBUG && VC_V7)
        Console.WriteLine("DEBUG and VC_V7 are defined");
        Console.WriteLine("DEBUG and VC_V7 are not defined");

Only useful for excluding parts of methods.

If you use #if to exclude some method from compilation then you will have to exclude from compilation all pieces of code which call that method as well (sometimes you may load some classes at runtime and you cannot find the caller with "Find all references"). Otherwise there will be errors.

If you use conditional compilation on the other hand you can still leave all pieces of code that call the method. All parameters will still be validated by the compiler. The method just won't be called at runtime. I think that it is way better to hide the method just once and not have to remove all the code that calls it as well. You are not allowed to use the conditional attribute on methods which return value - only on void methods. But I don't think this is a big limitation because if you use #if with a method that returns a value you have to hide all pieces of code that call it too.

Here is an example:

    // calling Class1.ConditionalMethod() will be ignored at runtime 
    // unless the DEBUG constant is defined

    using System.Diagnostics;
    class Class1 
       public static void ConditionalMethod() {
          Console.WriteLine("Executed Class1.ConditionalMethod");


I would use #ifdef in C++ but with C#/VB I would use Conditional attribute. This way you hide the method definition without having to hide the pieces of code that call it. The calling code is still compiled and validated by the compiler, the method is not called at runtime though. You may want to use #if to avoid dependencies because with Conditional attribute your code is still compiled.

Lock down Microsoft Excel macro

you can set a password to your vba code but this can be quite easily broken up.

you can also create an addin and compile it into a DLL. See here for more information. That's at least the most secure way to protect your code.


how to check if object already exists in a list

If it's maintainable to use those 2 properties, you could:

bool alreadyExists = myList.Any(x=> x.Foo=="ooo" && x.Bar == "bat");

How to use ADB to send touch events to device using sendevent command?

In order to do a particular action (for example to open the web browser), you need to first figure out where to tap. To do that, you can first run:

adb shell getevent -l

Once you press on the device, at the location that you want, you will see this output:

/dev/input/event3: EV_KEY       BTN_TOUCH            DOWN
/dev/input/event3: EV_ABS       ABS_MT_POSITION_X    000002f5
/dev/input/event3: EV_ABS       ABS_MT_POSITION_Y    0000069e

adb is telling you that a key was pressed (button down) at position 2f5, 69e in hex which is 757 and 1694 in decimal.

If you now want to generate the same event, you can use the input tap command at the same position:

adb shell input tap 757 1694

More info can be found at:

How do I use FileSystemObject in VBA?

After adding the reference, I had to use

Dim fso As New Scripting.FileSystemObject

server error:405 - HTTP verb used to access this page is not allowed

In my case, IIS was fine but.. uh.. all the files in the folder except web.config had been deleted (a manual deployment half-done on a test site).

Position an element relative to its container

Absolute positioning positions an element relative to its nearest positioned ancestor. So put position: relative on the container, then for child elements, top and left will be relative to the top-left of the container so long as the child elements have position: absolute. More information is available in the CSS 2.1 specification.

How to read values from the querystring with ASP.NET Core?

You can just create an object like this:

public class SomeQuery
    public string SomeParameter { get; set; }
    public int? SomeParameter2 { get; set; }

And then in controller just make something like that:

public IActionResult FindSomething([FromQuery] SomeQuery query)
    // Your implementation goes here..

Even better, you can create API model from:

public IActionResult GetSomething([FromRoute] int someId, [FromQuery] SomeQuery query)


public IActionResult GetSomething(ApiModel model)

public class ApiModel
    public int SomeId { get; set; }
    public string SomeParameter { get; set; }
    public int? SomeParameter2 { get; set; }

Setting onSubmit in React.js

You can pass the event as argument to the function and then prevent the default behaviour.

var OnSubmitTest = React.createClass({
        render: function() {
        doSomething = function(event){
           alert('it works!');

        return <form onSubmit={this.doSomething}>
        <button>Click me</button>

Find duplicate records in MySQL

    Find duplicate Records:

    Suppose we have table : Student 
    student_id int
    student_name varchar
    | student_id | student_name        |
    |        101 | usman               |
    |        101 | usman               |
    |        101 | usman               |
    |        102 | usmanyaqoob         |
    |        103 | muhammadusmanyaqoob |
    |        103 | muhammadusmanyaqoob |

    Now we want to see duplicate records
    Use this query:

   select student_name,student_id ,count(*) c from student group by student_id,student_name having c>1;

| student_name        | student_id | c |
| usman               |        101 | 3 |
| muhammadusmanyaqoob |        103 | 2 |

Rails Object to hash


as_json has very flexible way to configure complex object according to model relations


Model campaign belongs to shop and has one list

Model list has many list_tasks and each of list_tasks has many comments

We can get one json which combines all those data easily.

        except: [:created_at, :updated_at],
        include: {
            shop: {
                except: [:created_at, :updated_at, :customer_id],
                include: {customer: {except: [:created_at, :updated_at]}}},
            list: {
                except: [:created_at, :updated_at, :observation_id],
                include: {
                    list_tasks: {
                        except: [:created_at, :updated_at],
                        include: {comments: {except: [:created_at, :updated_at]}}
        methods: :tags

Notice methods: :tags can help you attach any additional object which doesn't have relations with others. You just need to define a method with name tags in model campaign. This method should return whatever you need (e.g. Tags.all)

Official documentation for as_json

Oracle pl-sql escape character (for a " ' ")

To escape it, double the quotes:

INSERT INTO TABLE_A VALUES ( 'Alex''s Tea Factory' );

How do I remove the height style from a DIV using jQuery?

to remove the height:

$('div#someDiv').css('height', '');
$('div#someDiv').css('height', null);

like John pointed out, set height to auto:

$('div#someDiv').css('height', 'auto');

(checked with jQuery 1.4)

How to clone object in C++ ? Or Is there another solution?

In C++ copying the object means cloning. There is no any special cloning in the language.

As the standard suggests, after copying you should have 2 identical copies of the same object.

There are 2 types of copying: copy constructor when you create object on a non initialized space and copy operator where you need to release the old state of the object (that is expected to be valid) before setting the new state.

how to toggle (hide/show) a table onClick of <a> tag in java script

You are always passing in true to the toggleMethod, so it will always "show" the table. I would create a global variable that you can flip inside the toggle method instead.

Alternatively you can check the visibility state of the table instead of an explicit variable

The default for KeyValuePair

To avoid the boxing of KeyValuePair.Equals(object) you can use a ValueTuple.

if ((getResult.Key, getResult.Value) == default)

powershell mouse move does not prevent idle mode

I created a PS script to check idle time and jiggle the mouse to prevent the screensaver.

There are two parameters you can control how it works.

$checkIntervalInSeconds : the interval in seconds to check if the idle time exceeds the limit

$preventIdleLimitInSeconds : the idle time limit in seconds. If the idle time exceeds the idle time limit, jiggle the mouse to prevent the screensaver

Here we go. Save the script in preventIdle.ps1. For preventing the 4-min screensaver, I set $checkIntervalInSeconds = 30 and $preventIdleLimitInSeconds = 180.

Add-Type @'
using System;
using System.Diagnostics;
using System.Runtime.InteropServices;

namespace PInvoke.Win32 {

    public static class UserInput {

        [DllImport("user32.dll", SetLastError=false)]
        private static extern bool GetLastInputInfo(ref LASTINPUTINFO plii);

        private struct LASTINPUTINFO {
            public uint cbSize;
            public int dwTime;

        public static DateTime LastInput {
            get {
                DateTime bootTime = DateTime.UtcNow.AddMilliseconds(-Environment.TickCount);
                DateTime lastInput = bootTime.AddMilliseconds(LastInputTicks);
                return lastInput;

        public static TimeSpan IdleTime {
            get {
                return DateTime.UtcNow.Subtract(LastInput);

        public static double IdleSeconds {
            get {
                return IdleTime.TotalSeconds;

        public static int LastInputTicks {
            get {
                LASTINPUTINFO lii = new LASTINPUTINFO();
                lii.cbSize = (uint)Marshal.SizeOf(typeof(LASTINPUTINFO));
                GetLastInputInfo(ref lii);
                return lii.dwTime;

Add-Type @'
using System;
using System.Runtime.InteropServices;

namespace MouseMover
    public class MouseSimulator
        [DllImport("user32.dll", SetLastError = true)]
        static extern uint SendInput(uint nInputs, ref INPUT pInputs, int cbSize);
        [return: MarshalAs(UnmanagedType.Bool)]
        public static extern bool GetCursorPos(out POINT lpPoint);

        struct INPUT
            public SendInputEventType type;
            public MouseKeybdhardwareInputUnion mkhi;
        struct MouseKeybdhardwareInputUnion
            public MouseInputData mi;

            public KEYBDINPUT ki;

            public HARDWAREINPUT hi;
        struct KEYBDINPUT
            public ushort wVk;
            public ushort wScan;
            public uint dwFlags;
            public uint time;
            public IntPtr dwExtraInfo;
        struct HARDWAREINPUT
            public int uMsg;
            public short wParamL;
            public short wParamH;
        public struct POINT
            public int X;
            public int Y;

            public POINT(int x, int y)
                this.X = x;
                this.Y = y;
        struct MouseInputData
            public int dx;
            public int dy;
            public uint mouseData;
            public MouseEventFlags dwFlags;
            public uint time;
            public IntPtr dwExtraInfo;

        enum MouseEventFlags : uint
            MOUSEEVENTF_MOVE = 0x0001
        enum SendInputEventType : int
        public static void MoveMouseBy(int x, int y) {
            INPUT mouseInput = new INPUT();
            mouseInput.type = SendInputEventType.InputMouse;
            mouseInput.mkhi.mi.dwFlags = MouseEventFlags.MOUSEEVENTF_MOVE;
            mouseInput.mkhi.mi.dx = x;
            mouseInput.mkhi.mi.dy = y;
            SendInput(1, ref mouseInput, Marshal.SizeOf(mouseInput));

$checkIntervalInSeconds = 30
$preventIdleLimitInSeconds = 180

while($True) {
    if (([PInvoke.Win32.UserInput]::IdleSeconds -ge $preventIdleLimitInSeconds)) {
    Start-Sleep -Seconds $checkIntervalInSeconds

Then, open Windows PowerShell and run

powershell -ExecutionPolicy ByPass -File C:\SCRIPT-DIRECTORY-PATH\preventIdle.ps1

How to use classes from .jar files?

Let's say we need to use the class Classname that is contained in the jar file org.example.jar

And your source is in the file Like this:

import org.example.Classname;

public class mysource {
    public static void main(String[] argv) {

First, as you see, in your code you have to import the classes. To do that you need import org.example.Classname;

Second, when you compile the source, you have to reference the jar file.

Please note the difference in using : and ; while compiling

  • If you are under a unix like operating system:

    javac -cp '.:org.example.jar'
  • If you are under windows:

    javac -cp .;org.example.jar

After this, you obtain the bytecode file mysource.class

Now you can run this :

  • If you are under a unix like operating system:

    java -cp '.:org.example.jar' mysource
  • If you are under windows:

    java -cp .;org.example.jar mysource

Where do I find the current C or C++ standard documents?

The actual standards documents may not be the most useful. Most compilers do not fully implement the standards and may sometimes actually conflict. So the compiler documentation that you would already have will be more useful. Additionally, the documentation will contain platform-specific remarks and notes on any caveats.

How to get object length

This should do it:


However, Object.keys is not supported in IE8 and below, Opera and FF 3.6 and below.

Live demo:

$.widget is not a function

I got this error recently by introducing an old plugin to wordpress. It loaded an older version of jquery, which happened to be placed before the jquery mouse file. There was no jquery widget file loaded with the second version, which caused the error.

No error for using the extra jquery library -- that's a problem especially if a silent fail might have happened, causing a not so silent fail later on.

A potential way around it for wordpress might be to be explicit about the dependencies that way the jquery mouse would follow the widget which would follow the correct core leaving the other jquery to be loaded afterwards. Still might cause a production error later if you don't catch that and change the default function for jquery for the second version in all the files associated with it.

How should I validate an e-mail address?

You can do any type of validation in android very easily by the oval.jar file. OVal is a pragmatic and extensible general purpose validation framework for any kind of Java objects.

follow this link:

You can downlaod this from here:

You can use validation by setting tags in variables

public class Something{

    @NotEmpty  //not empty validation
    @Email     //email validation
    private String emailAddress;

   private void checkValidation() {
        Something forgotpass.setEmailAddress(LoginActivity.this.dialog_email.getText().toString());
        Validator validator = new Validator();
        //collect the constraint violations
        List<ConstraintViolation> violations = validator.validate(forgotpass);
            for (ConstraintViolation cv : violations){
                    dialog_email.setError(ValidationMessage.formattedError(cv.getMessage(), forgotpass));

How can I change the color of pagination dots of UIPageControl?

pageControl.pageIndicatorTintColor = [UIColor redColor];
pageControl.currentPageIndicatorTintColor = [UIColor redColor];

works for iOS6

How to change line width in IntelliJ (from 120 character)

I didn't understand why my this didn't work but I found out that this setting is now also under the programming language itself at:

'Editor' | 'Code Style' | < your language > | 'Wrapping and Braces' | 'Right margin (columns)'

SQL Server Text type vs. varchar data type

There has been some major changes in ms 2008 -> Might be worth considering the following article when making a decisions on what data type to use.

Bytes per

  1. varchar(max), varbinary(max), xml, text, or image column 2^31-1 2^31-1
  2. nvarchar(max) column 2^30-1 2^30-1

Write a mode method in Java to find the most frequently occurring element in an array

import java.util.HashMap;

public class SmallestHighestRepeatedNumber { static int arr[] = { 9, 4, 5, 9, 2, 9, 1, 2, 8, 1, 1, 7, 7 };

public static void main(String[] args) {
    int mode = mode(arr);

public static int mode(int[] array) {
    HashMap<Integer, Integer> hm = new HashMap<Integer, Integer>();
    int max = 1;
    int temp = 0;

    for (int i = 0; i < array.length; i++) {

        if (hm.get(array[i]) != null) {

            int count = hm.get(array[i]);
            hm.put(array[i], count);

            if (count > max || temp > array[i] && count == max) {
                temp = array[i];
                max = count;
        } else
            hm.put(array[i], 1);
    return temp;


How to use shared memory with Linux in C

try this code sample, I tested it, source:

#include <stdio.h> 
#include <sys/shm.h> 
#include <sys/stat.h> 

int main () 
  int segment_id; 
  char* shared_memory; 
  struct shmid_ds shmbuffer; 
  int segment_size; 
  const int shared_segment_size = 0x6400; 

  /* Allocate a shared memory segment.  */ 
  segment_id = shmget (IPC_PRIVATE, shared_segment_size, 
                 IPC_CREAT | IPC_EXCL | S_IRUSR | S_IWUSR); 
  /* Attach the shared memory segment.  */ 
  shared_memory = (char*) shmat (segment_id, 0, 0); 
  printf ("shared memory attached at address %p\n", shared_memory); 
  /* Determine the segment's size. */ 
  shmctl (segment_id, IPC_STAT, &shmbuffer); 
  segment_size  =               shmbuffer.shm_segsz; 
  printf ("segment size: %d\n", segment_size); 
  /* Write a string to the shared memory segment.  */ 
  sprintf (shared_memory, "Hello, world."); 
  /* Detach the shared memory segment.  */ 
  shmdt (shared_memory); 

  /* Reattach the shared memory segment, at a different address.  */ 
  shared_memory = (char*) shmat (segment_id, (void*) 0x5000000, 0); 
  printf ("shared memory reattached at address %p\n", shared_memory); 
  /* Print out the string from shared memory.  */ 
  printf ("%s\n", shared_memory); 
  /* Detach the shared memory segment.  */ 
  shmdt (shared_memory); 

  /* Deallocate the shared memory segment.  */ 
  shmctl (segment_id, IPC_RMID, 0); 

  return 0; 

Increase max_execution_time in PHP?

Theres a setting max_input_time (on Apache) for many webservers that defines how long they will wait for post data, regardless of the size. If this time runs out the connection is closed without even touching the php.

So your problem is not necessarily solvable with php only but you will need to change the server settings too.

Android BroadcastReceiver within Activity

Your also have to register the receiver in onCreate(), like this:

IntentFilter filter = new IntentFilter();
registerReceiver(receiver, filter);

"NODE_ENV" is not recognized as an internal or external command, operable command or batch file

set NODE_ENV=production & nodemon app/app.js

will cause NODE_ENV to contain a space at the end:

process.env.NODE_ENV == 'production'; //false
process.env.NODE_ENV == 'production '; //true

As mentioned in a comment here, use this instead:

NODE_ENV=production&& nodemon app/app.js

Get item in the list in Scala?

Safer is to use lift so you can extract the value if it exists and fail gracefully if it does not.


This will return None if the list isn't long enough to provide that element, and Some(value) if it is.

scala> val l = List("a", "b", "c")
scala> l.lift(1)
scala> l.lift(5)

Whenever you're performing an operation that may fail in this way it's great to use an Option and get the type system to help make sure you are handling the case where the element doesn't exist.


This works because List's apply (which sugars to just parentheses, e.g. l(index)) is like a partial function that is defined wherever the list has an element. The List.lift method turns the partial apply function (a function that is only defined for some inputs) into a normal function (defined for any input) by basically wrapping the result in an Option.

How can I create a temp file with a specific extension with .NET?

This could be handy for you... It's to create a temp. folder and return it as a string in VB.NET.

Easily convertible to C#:

Public Function GetTempDirectory() As String
    Dim mpath As String
        mpath = System.IO.Path.Combine(System.IO.Path.GetTempPath, System.IO.Path.GetRandomFileName)
    Loop While System.IO.Directory.Exists(mpath) Or System.IO.File.Exists(mpath)
    Return mpath
End Function

Python Pandas: Get index of rows which column matches certain value

Can be done using numpy where() function:

import pandas as pd
import numpy as np

In [716]: df = pd.DataFrame({"gene_name": ['SLC45A1', 'NECAP2', 'CLIC4', 'ADC', 'AGBL4'] , "BoolCol": [False, True, False, True, True] },

In [717]: df
  BoolCol gene_name
a   False   SLC45A1
b    True    NECAP2
c   False     CLIC4
d    True       ADC
e    True     AGBL4

In [718]: np.where(df["BoolCol"] == True)
Out[718]: (array([1, 3, 4]),)

In [719]: select_indices = list(np.where(df["BoolCol"] == True)[0])

In [720]: df.iloc[select_indices]
  BoolCol gene_name
b    True    NECAP2
d    True       ADC
e    True     AGBL4

Though you don't always need index for a match, but incase if you need:

In [796]: df.iloc[select_indices].index
Out[796]: Index([u'b', u'd', u'e'], dtype='object')

In [797]: df.iloc[select_indices].index.tolist()
Out[797]: ['b', 'd', 'e']

Reverse Y-Axis in PyPlot

Alternatively, you can use the matplotlib.pyplot.axis() function, which allows you inverting any of the plot axis

ax = matplotlib.pyplot.axis()

Or if you prefer to only reverse the X-axis, then


Indeed, you can invert both axis:


$(this).serialize() -- How to add a value?

You can write an extra function to process form data and you should add your nonform data as the data valu in the form.seethe example :

<form method="POST" id="add-form">
    <div class="form-group required ">
        <label for="key">Enter key</label>
        <input type="text" name="key" id="key"  data-nonformdata="hai"/>
    <div class="form-group required ">
        <label for="name">Ente Name</label>
        <input type="text" name="name" id="name"  data-nonformdata="hello"/>
    <input type="submit" id="add-formdata-btn" value="submit">

Then add this jquery for form processing

        var formData = $("form").serializeArray();
        formData = processFormData(formData);
        // write further code here---->
    var data = formData;
        $('#add-form input').each(function(){
            if( =={
                var nonformData = $(this).data("nonformdata");
    return formData;

How can I display a modal dialog in Redux that performs asynchronous actions?

Wrap the modal into a connected container and perform the async operation in here. This way you can reach both the dispatch to trigger actions and the onClose prop too. To reach dispatch from props, do not pass mapDispatchToProps function to connect.

class ModalContainer extends React.Component {
  handleDelete = () => {
    const { dispatch, onClose } = this.props;
    dispatch({type: 'DELETE_POST'});

    someAsyncOperation().then(() => {
      dispatch({type: 'DELETE_POST_SUCCESS'});

  render() {
    const { onClose } = this.props;
    return <Modal onClose={onClose} onSubmit={this.handleDelete} />

export default connect(/* no map dispatch to props here! */)(ModalContainer);

The App where the modal is rendered and its visibility state is set:

class App extends React.Component {
  state = {
    isModalOpen: false

  handleModalClose = () => this.setState({ isModalOpen: false });


    return (
      <ModalContainer onClose={this.handleModalClose} />  


Android customized button; changing text color

ok very simple first go to 1. res-valuse and open colors.xml 2.copy 1 of the defined text their for example #FF4081 and change name for instance i changed to white and change its value for instance i changed to #FFFFFF for white value like this

<color name="White">#FFFFFF</color>

then inside your button add this line

 b3.setTextColor(ContextCompat.getColor(getApplicationContext(), R.color.White));

ok b3 is the name of my button so changed of the name of ur button all others will be same if u use white color if you change different color then change white to the name of your color but first you have define that color in colors.xml like i explained in pont 2

AngularJS: ng-repeat list is not updated when a model element is spliced from the model array

Remove "track by index" from the ng-repeat and it would refresh the DOM

How to get datas from List<Object> (Java)?

System.out.println("Element "+i+list.get(0));}

Should be

System.out.println("Element "+i+list.get(i));}

To use the JSF tags, you give the dataList value attribute a reference to your list of elements, and the var attribute is a local name for each element of that list in turn. Inside the dataList, you use properties of the object (getters) to output the information about that individual object:

<t:dataList id="myDataList" value="#{houseControlList}" var="element" rows="3" >
<t:outputText id="houseId" value="#{element.houseId}"/>

Clearing _POST array fully

The solutions so far don't work because the POST data is stored in the headers. A redirect solves this issue according this this post.

How to delete $_POST variable upon pressing 'Refresh' button on browser with PHP?

Split string, convert ToList<int>() in one line

You can also do it this way without the need of Linq:

List<int> numbers = new List<int>( Array.ConvertAll(sNumbers.Split(','), int.Parse) );

// Uses Linq
var numbers = Array.ConvertAll(sNumbers.Split(','), int.Parse).ToList();

What does ECU units, CPU core and memory mean when I launch a instance

ECU = EC2 Compute Unit. More from here:

Amazon EC2 uses a variety of measures to provide each instance with a consistent and predictable amount of CPU capacity. In order to make it easy for developers to compare CPU capacity between different instance types, we have defined an Amazon EC2 Compute Unit. The amount of CPU that is allocated to a particular instance is expressed in terms of these EC2 Compute Units. We use several benchmarks and tests to manage the consistency and predictability of the performance from an EC2 Compute Unit. One EC2 Compute Unit provides the equivalent CPU capacity of a 1.0-1.2 GHz 2007 Opteron or 2007 Xeon processor. This is also the equivalent to an early-2006 1.7 GHz Xeon processor referenced in our original documentation. Over time, we may add or substitute measures that go into the definition of an EC2 Compute Unit, if we find metrics that will give you a clearer picture of compute capacity.

Connect with SSH through a proxy

This is how I solved it, hoping to help others later.

My system is debian 10, and minimal installation.

I also have the same problem like this.

git clone [email protected]:nothing/nothing.git
Cloning into 'nothing'...
nc: invalid option -- 'x'
nc -h for help
ssh_exchange_identification: Connection closed by remote host
fatal: Could not read from remote repository.

Please make sure you have the correct access rights
and the repository exists.


git clone [email protected]:nothing/nothing.git
Cloning into 'nothing'...
/usr/bin/nc: invalid option -- 'X'
nc -h for help
ssh_exchange_identification: Connection closed by remote host
fatal: Could not read from remote repository.

Please make sure you have the correct access rights
and the repository exists.

So, I know the nc has different versions like openbsd-netcat and GNU-netcat, you can change the nc in debian to the openbsd version, but I choose to change the software like corkscrew, because the names of the two versions of nc in system are same, and many people don’t understand it well. My approach is as follows.

sudo apt install corkscrew


vim ~/.ssh/config

Change this file like this.

    User git
    ProxyCommand corkscrew 8118 %h %p and 8118 is my proxy server's address and port, you should change it according to your server address.

It's work fine.

Thanks @han.

How can I send a file document to the printer and have it print?

You can tell Acrobat Reader to print the file using (as someone's already mentioned here) the 'print' verb. You will need to close Acrobat Reader programmatically after that, too:

private void SendToPrinter()
   ProcessStartInfo info = new ProcessStartInfo();
   info.Verb = "print";
   info.FileName = @"c:\output.pdf";
   info.CreateNoWindow = true;
   info.WindowStyle = ProcessWindowStyle.Hidden;

   Process p = new Process();
   p.StartInfo = info;

   if (false == p.CloseMainWindow())

This opens Acrobat Reader and tells it to send the PDF to the default printer, and then shuts down Acrobat after three seconds.

If you are willing to ship other products with your application then you could use GhostScript (free), or a command-line PDF printer such as (commercial).

Note: the sample code opens the PDF in the application current registered to print PDFs, which is the Adobe Acrobat Reader on most people's machines. However, it is possible that they use a different PDF viewer such as Foxit ( The sample code should still work, though.

javascript return true or return false when and how to use it?

I think a lot of times when you see this code, it's from people who are in the habit of event handlers for forms, buttons, inputs, and things of that sort.

Basically, when you have something like:

<form onsubmit="return callSomeFunction();"></form>


<a href="#" onclick="return callSomeFunction();"></a>`

and callSomeFunction() returns true, then the form or a will submit, otherwise it won't.

Other more obvious general purposes for returning true or false as a result of a function are because they are expected to return a boolean.

How to Load Ajax in Wordpress

Firstly, you should read this page thoroughly

Secondly, ajax_script is not defined so you should change to: url: ajaxurl. I don't see your function1() in the above code but you might already define it in other file.

And finally, learn how to debug ajax call using Firebug, network and console tab will be your friends. On the PHP side, print_r() or var_dump() will be your friends.

How can I add a hint or tooltip to a label in C# Winforms?

System.Windows.Forms.ToolTip ToolTip1 = new System.Windows.Forms.ToolTip();
ToolTip1.SetToolTip( Label1, "Label for Label1");

How can I use threading in Python?

Since this question was asked in 2010, there has been real simplification in how to do simple multithreading with Python with map and pool.

The code below comes from an article/blog post that you should definitely check out (no affiliation) - Parallelism in one line: A Better Model for Day to Day Threading Tasks. I'll summarize below - it ends up being just a few lines of code:

from multiprocessing.dummy import Pool as ThreadPool
pool = ThreadPool(4)
results =, my_array)

Which is the multithreaded version of:

results = []
for item in my_array:


Map is a cool little function, and the key to easily injecting parallelism into your Python code. For those unfamiliar, map is something lifted from functional languages like Lisp. It is a function which maps another function over a sequence.

Map handles the iteration over the sequence for us, applies the function, and stores all of the results in a handy list at the end.

Enter image description here


Parallel versions of the map function are provided by two libraries:multiprocessing, and also its little known, but equally fantastic step child:multiprocessing.dummy.

multiprocessing.dummy is exactly the same as multiprocessing module, but uses threads instead (an important distinction - use multiple processes for CPU-intensive tasks; threads for (and during) I/O):

multiprocessing.dummy replicates the API of multiprocessing, but is no more than a wrapper around the threading module.

import urllib2
from multiprocessing.dummy import Pool as ThreadPool

urls = [

# Make the Pool of workers
pool = ThreadPool(4)

# Open the URLs in their own threads
# and return the results
results =, urls)

# Close the pool and wait for the work to finish

And the timing results:

Single thread:   14.4 seconds
       4 Pool:   3.1 seconds
       8 Pool:   1.4 seconds
      13 Pool:   1.3 seconds

Passing multiple arguments (works like this only in Python 3.3 and later):

To pass multiple arrays:

results = pool.starmap(function, zip(list_a, list_b))

Or to pass a constant and an array:

results = pool.starmap(function, zip(itertools.repeat(constant), list_a))

If you are using an earlier version of Python, you can pass multiple arguments via this workaround).

(Thanks to user136036 for the helpful comment.)

Can I convert long to int?


Though I don't know what it will do when it's greater than int.MaxValue.

conflicting types for 'outchar'

It's because you haven't declared outchar before you use it. That means that the compiler will assume it's a function returning an int and taking an undefined number of undefined arguments.

You need to add a prototype pf the function before you use it:

void outchar(char);  /* Prototype (declaration) of a function to be called */  int main(void) {     ... }  void outchar(char ch) {     ... } 

Note the declaration of the main function differs from your code as well. It's actually a part of the official C specification, it must return an int and must take either a void argument or an int and a char** argument.

How to pass values arguments to function in Bootstrap


$(document).ready(function() {
    $('#createFormId').on('', function(event) {

How can I set the value of a DropDownList using jQuery?

Here is a function made to quickly set the selected option:

function SetSelected(elem, val){
        $('#'+elem+' option').each(function(i,d){
        //  console.log('searching match for '+ elem + '  ' + d.value + ' equal to '+ val);
            if($.trim(d.value).toLowerCase() == $.trim(val).toLowerCase()){
        //      console.log('found match for '+ elem + '  ' + d.value);
                $('#'+elem).prop('selectedIndex', i);

Call this function with argument element id and selected value; like this:

SetSelected('selectID','some option');

It is useful when there are lot of select options to be set.

Using both Python 2.x and Python 3.x in IPython Notebook

Use sudo pip3 install jupyter for installing jupyter for python3 and sudo pip install jupyter for installing jupyter notebook for python2. Then, you can call ipython kernel install command to enable both types of notebook to choose from in jupyter notebook.

Get a random item from a JavaScript array

An alternate way would be to add a method to the Array prototype:

 Array.prototype.random = function (length) {
       return this[Math.floor((Math.random()*length))];

 var teams = ['patriots', 'colts', 'jets', 'texans', 'ravens', 'broncos']
 var chosen_team = teams.random(teams.length)

Print commit message of a given commit in git

It's not "plumbing", but it'll do exactly what you want:

$ git log --format=%B -n 1 <commit>

If you absolutely need a "plumbing" command (not sure why that's a requirement), you can use rev-list:

$ git rev-list --format=%B --max-count=1 <commit>

Although rev-list will also print out the commit sha (on the first line) in addition to the commit message.

Different names of JSON property during serialization and deserialization

You can use a combination of @JsonSetter, and @JsonGetter to control the deserialization, and serialization of your property, respectively. This will also allow you to keep standardized getter and setter method names that correspond to your actual field name.

import com.fasterxml.jackson.annotation.JsonSetter;    
import com.fasterxml.jackson.annotation.JsonGetter;

class Coordinates {
    private int red;

    //# Used during serialization
    public int getRed() {
        return red;

    //# Used during deserialization
    public void setRed(int red) { = red;

How to ping ubuntu guest on VirtualBox

Using NAT (the default) this is not possible. Bridged Networking should allow it. If bridged does not work for you (this may be the case when your network adminstration does not allow multiple IP addresses on one physical interface), you could try 'Host-only networking' instead.

For configuration of Host-only here is a quote from the vbox manual(which is pretty good).

For host-only networking, like with internal networking, you may find the DHCP server useful that is built into VirtualBox. This can be enabled to then manage the IP addresses in the host-only network since otherwise you would need to configure all IP addresses statically.

In the VirtualBox graphical user interface, you can configure all these items in the global settings via "File" -> "Settings" -> "Network", which lists all host-only networks which are presently in use. Click on the network name and then on the "Edit" button to the right, and you can modify the adapter and DHCP settings.

Pandas DataFrame Groupby two columns and get counts

Followed by @Andy's answer, you can do following to solve your second question:

In [56]: df.groupby(['col5','col2']).size().reset_index().groupby('col2')[[0]].max()
A     3
B     2
C     1
D     3

How to break out of nested loops?


if (condition) {
    i = j = 1000;

onchange event for html.dropdownlist

You can try this if you are passing a value to the action method.

@Html.DropDownList("Sortby", new SelectListItem[] { new SelectListItem() { Text = "Newest to Oldest", Value = "0" }, new SelectListItem() { Text = "Oldest to Newest", Value = "1" }},new { onchange = "document.location.href = '/ControllerName/ActionName?id=' + this.options[this.selectedIndex].value;" })

Remove the query string in case of no parameter passing.

What are the possible values of the Hibernate configuration and what do they do

  • validate: validates the schema, no change happens to the database.
  • update: updates the schema with current execute query.
  • create: creates new schema every time, and destroys previous data.
  • create-drop: drops the schema when the application is stopped or SessionFactory is closed explicitly.

how to force maven to update local repo

If you are struggling with authenticating to a site, and Maven is caching the results, simply removing the meta-data about the site from the meta-data stash will force Maven to revisit the site.

gvim <local-git-repository>/commons-codec/

How do I tidy up an HTML file's indentation in VI?

You can integrate both tidy and html-beautify automatically by installing the plugin vim-autoformat. After that, you can execute whichever formatter is installed with a single keystroke.

GIT vs. Perforce- Two VCS will enter... one will leave

I have no experience with Git, but I have with Mercurial which is also a distributed VCS. It depends on the project really, but in our case a distributed VCS suited the project as basically eliminated frequent broken builds.

I think it depends on the project really, as some are better suited towards a client-server VCS, and others towads a distributed one.

Classpath including JAR within a JAR

You need to build a custom class-loader to do this or a third-party library that supports this. Your best bet is to extract the jar from the runtime and add them to the classpath (or have them already added to the classpath).

Remove HTML Tags in Javascript with Regex

Like others have stated, regex will not work. Take a moment to read my article about why you cannot and should not try to parse html with regex, which is what you're doing when you're attempting to strip html from your source string.

How to pass ArrayList<CustomeObject> from one activity to another?

Use this code to pass arraylist<customobj> to anthother Activity

firstly serialize our contact bean

public class ContactBean implements Serializable {
      //do intialization here

Now pass your arraylist

 Intent intent = new Intent(this,name of activity.class);

SQL Server: What is the difference between CROSS JOIN and FULL OUTER JOIN?

I'd like to add one important aspect to other answers, which actually explained this topic to me in the best way:

If 2 joined tables contain M and N rows, then cross join will always produce (M x N) rows, but full outer join will produce from MAX(M,N) to (M + N) rows (depending on how many rows actually match "on" predicate).


From logical query processing perspective, CROSS JOIN does indeed always produce M x N rows. What happens with FULL OUTER JOIN is that both left and right tables are "preserved", as if both LEFT and RIGHT join happened. So rows, not satisfying ON predicate, from both left and right tables are added to the result set.

What is a segmentation fault?

A segmentation fault or access violation occurs when a program attempts to access a memory location that is not exist, or attempts to access a memory location in a way that is not allowed.

 /* "Array out of bounds" error 
   valid indices for array foo
   are 0, 1, ... 999 */
   int foo[1000];
   for (int i = 0; i <= 1000 ; i++) 
   foo[i] = i;

Here i[1000] not exist, so segfault occurs.

Causes of segmentation fault:

it arise primarily due to errors in use of pointers for virtual memory addressing, particularly illegal access.

De-referencing NULL pointers – this is special-cased by memory management hardware.

Attempting to access a nonexistent memory address (outside process’s address space).

Attempting to access memory the program does not have rights to (such as kernel structures in process context).

Attempting to write read-only memory (such as code segment).

Reading a List from properties file and load with spring annotation @Value

if using property placeholders then ser1702544 example would become

@Value("#{myConfigProperties['myproperty'].trim().replaceAll(\"\\s*(?=,)|(?<=,)\\s*\", \"\").split(',')}") 

With placeholder xml:

<bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">   
    <property name="properties" ref="myConfigProperties" />
    <property name="placeholderPrefix"><value>$myConfigProperties{</value></property>

<bean id="myConfigProperties" class="org.springframework.beans.factory.config.PropertiesFactoryBean">
     <property name="locations">

key_load_public: invalid format

The error is misleading - it says "pubkey" while pointing to a private key file ~/.ssh/id_rsa.

In my case, it was simply a missing public key (as I haven't restored it from a vault).


I used to skip deploying ~/.ssh/ by automated scripts.

All ssh usages worked, but the error made me think of a possible mess.

Not at all - strace helped to notice that the trigger was actually the *.pub file:

strace ssh
openat(AT_FDCWD, "/home/uvsmtid/.ssh/", O_RDONLY) = -1 ENOENT (No such file or directory)
write(2, "load pubkey \"/home/uvsmtid/.ssh/"..., 57) = 57
load pubkey "/home/uvsmtid/.ssh/id_rsa": invalid format

How to calculate distance from Wifi router using Signal Strength?

Don't care if you are a moderator. I wrote my text towards my audience not as a technical writer

All you guys need to learn to navigate with tools that predate GPS. Something like a sextant, octant, backstaff or an astrolabe.

If you have receive the signal from 3 different locations then you only need to measure the signal strength and make a ratio from those locations. Simple triangle calculation where a2+b2=c2. The stronger the signal strength the closer the device is to the receiver.

Error: could not find function ... in R

I got the same, error, I was running version .99xxx, I checked for updates from help menu and updated My RStudio to 1.0x, then the error did not come

So simple solution, just update your R Studio

MYSQL Truncated incorrect DOUBLE value

Try replacing the AND with ,

UPDATE shop_category 
SET name = 'Secolul XVI - XVIII', name_eng = '16th to 18th centuries' 
WHERE category_id = 4768

The UPDATE Syntax shows comma should be used as the separator.

Getting execute permission to xp_cmdshell

Time to contribute now. I am sysadmin role and worked on getting two public access users to execute xp_cmdshell. I am able to execute xp_cmdshell but not the two users.

I did the following steps:

  1. create new role:

    use master
    CREATE ROLE [CmdShell_Executor] AUTHORIZATION [dbo]
    GRANT EXEC ON xp_cmdshell TO [CmdShell_Executor]

  2. add users in master database: Security --> Users. Membership checks only [CmdShell_Executor] that is just created

  3. set up proxy account:

    EXEC sp_xp_cmdshell_proxy_account 'domain\user1','users1 Windows password'
    EXEC sp_xp_cmdshell_proxy_account 'domain\user2','users2 Windows password'

Then both users can execute the stored procedure that contains xp_cmdshell invoking a R script run. I let the users come to my PC to type in the password, execute the one line code, then delete the password.

What is the difference between ManualResetEvent and AutoResetEvent in .NET?


is similar to


as an atomic operation

How do you split a list into evenly sized chunks?

If you don't care about the order:

> from itertools import groupby
> batch_no = 3
> data = 'abcdefgh'

> [
    [x[1] for x in x[1]] 
    for x in 
        (x[0] % batch_no, x[1]) 
        for x in 
      key=lambda x: x[0]

[['a', 'd', 'g'], ['b', 'e', 'h'], ['c', 'f']]

This solution doesn't generates sets of same size, but distributes values so batches are as big as possible while keeping the number of generated batches.

How can I use custom fonts on a website?

You can use CSS3 font-face or webfonts

@font-face usage

@font-face {
   font-family: Delicious; 
   src: url('Delicious-Roman.otf');


take a look at Google Webfonts,

Command for restarting all running docker containers?

If you have docker-compose, all you need to do is:

docker-compose restart 

And you get nice print out of the container's name along with its status of the restart (done/error)

Here is the official guide for installing:

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

enter image description here

import matplotlib.pyplot as plt

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

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

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

Assign an initial value to radio button as checked

Note that if you have two radio button with same "name" attribute and they have "required" attribute, then adding "checked" attribute to them won't make them checked.

Example: This makes both radio button remain unchecked.

<input type="radio" name="gender" value="male" required <?php echo "checked"; ?>/>
<input type="radio" name="gender" value="female" required />

This will makes the "male" radio button checked.

<input type="radio" name="gender" value="male" <?php echo "checked"; ?>/>
<input type="radio" name="gender" value="female" />

Submit form after calling e.preventDefault()

Sorry for delay, but I will try to make perfect form :)

I will added Count validation steps and check every time not .val(). Check .length, because I think is better pattern in your case. Of course remove unbind function.

My jsFiddle

Of course source code:

// Prevent form submit if any entrees are missing


    var formIsValid = true;

    // Count validation steps
    var validationLoop = 0;

    // Cycle through each Attendee Name
    $('[name="atendeename[]"]', this).each(function(index, el){

        // If there is a value
        if ($(el).val().length > 0) {

            // Find adjacent entree input
            var entree = $(el).next('input');

            var entreeValue = entree.val();

            // If entree is empty, don't submit form
            if (entreeValue.length === 0) {
                alert('Please select an entree');
                formIsValid = false;
                return false;



    if (formIsValid && validationLoop > 0) {
        alert("Correct Form");
        return true;
    } else {
        return false;



The problem is you are not in the correct directory. A simple fix in Jupyter is to do the following command:

  1. Move to the GitHub directory for your installation
  2. Run the GitHub command

Here is an example command to use in Jupyter:

cd /home/ec2-user/ml_volume/GitHub_BMM
git show

Note you need to do the commands in the same cell.

how to set the background color of the whole page in css

The problem is that the body of the page isn't actually visible. The DIVs under have width of 100% and have background colors themselves that override the body CSS.

To Fix the no-man's land, this might work. It's not elegant, but works.

#doc3 {
    margin: auto 10px;
    width: auto;
    height: 2000px;
    background-color: yellow;