Programs & Examples On #Bitmapframe

Create WordPress Page that redirects to another URL

I'm not familiar with Wordpress templates, but I'm assuming that headers are sent to the browser by WP before your template is even loaded. Because of that, the common redirection method of:

header("Location: new_url");

won't work. Unless there's a way to force sending headers through a template before WP does anything, you'll need to use some Javascript like so:

<script language="javascript" type="text/javascript">
document.location = "new_url";

Put that in the section and it'll be run when the page loads. This method won't be instant, and it also won't work for people with Javascript disabled.

Difference between using Makefile and CMake to compile the code

The statement about CMake being a "build generator" is a common misconception.

It's not technically wrong; it just describes HOW it works, but not WHAT it does.

In the context of the question, they do the same thing: take a bunch of C/C++ files and turn them into a binary.

So, what is the real difference?

  • CMake is much more high-level. It's tailored to compile C++, for which you write much less build code, but can be also used for general purpose build. make has some built-in C/C++ rules as well, but they are useless at best.

  • CMake does a two-step build: it generates a low-level build script in ninja or make or many other generators, and then you run it. All the shell script pieces that are normally piled into Makefile are only executed at the generation stage. Thus, CMake build can be orders of magnitude faster.

  • The grammar of CMake is much easier to support for external tools than make's.

  • Once make builds an artifact, it forgets how it was built. What sources it was built from, what compiler flags? CMake tracks it, make leaves it up to you. If one of library sources was removed since the previous version of Makefile, make won't rebuild it.

  • Modern CMake (starting with version 3.something) works in terms of dependencies between "targets". A target is still a single output file, but it can have transitive ("public"/"interface" in CMake terms) dependencies. These transitive dependencies can be exposed to or hidden from the dependent packages. CMake will manage directories for you. With make, you're stuck on a file-by-file and manage-directories-by-hand level.

You could code up something in make using intermediate files to cover the last two gaps, but you're on your own. make does contain a Turing complete language (even two, sometimes three counting Guile); the first two are horrible and the Guile is practically never used.

To be honest, this is what CMake and make have in common -- their languages are pretty horrible. Here's what comes to mind:

  • They have no user-defined types;
  • CMake has three data types: string, list, and a target with properties. make has one: string;
  • you normally pass arguments to functions by setting global variables.
    • This is partially dealt with in modern CMake - you can set a target's properties: set_property(TARGET helloworld APPEND PROPERTY INCLUDE_DIRECTORIES "${CMAKE_CURRENT_SOURCE_DIR}");
  • referring to an undefined variable is silently ignored by default;

How to read integer values from text file

You can use a Scanner and its nextInt() method.
Scanner also has nextLong() for larger integers, if needed.

Reflection: How to Invoke Method with parameters

A fundamental mistake is here:

result = methodInfo.Invoke(methodInfo, parametersArray); 

You are invoking the method on an instance of MethodInfo. You need to pass in an instance of the type of object that you want to invoke on.

result = methodInfo.Invoke(classInstance, parametersArray);

What are the complexity guarantees of the standard containers?

Another quick lookup table is available at this github page

Note : This does not consider all the containers such as, unordered_map etc. but is still great to look at. It is just a cleaner version of this

Artisan migrate could not find driver

If you are on linux systems please try running sudo php artisan migrate As for me,sometimes database operations need to run with sudo in laravel.

Send Email to multiple Recipients with MailMessage?

According to the Documentation :

MailMessage.To property - Returns MailAddressCollection that contains the list of recipients of this email message

Here MailAddressCollection has a in built method called

   public void Add(string addresses)

   1. Summary:
          Add a list of email addresses to the collection.

   2. Parameters:
                *The email addresses to add to the System.Net.Mail.MailAddressCollection. Multiple
                *email addresses must be separated with a comma character (",").     

Therefore requirement in case of multiple recipients : Pass a string that contains email addresses separated by comma

In your case :

simply replace all the ; with ,

Msg.To.Add(toEmail.replace(";", ","));

For reference :


How to remove margin space around body or clear default css styles

try to ad the following in your CSS:

body, html{

How to show another window from mainwindow in QT

  1. Implement a slot in your QMainWindow where you will open your new Window,
  2. Place a widget on your QMainWindow,
  3. Connect a signal from this widget to a slot from the QMainWindow (for example: if the widget is a QPushButton connect the signal click() to the QMainWindow custom slot you have created).

Code example:


// ...
include "newwindow.h"
// ...
public slots:
   void openNewWindow();
// ...
   NewWindow *mMyNewWindow;
// ...


// ...
      // ...
      connect(mMyButton, SIGNAL(click()), this, SLOT(openNewWindow()));
      // ...
// ...
void MainWindow::openNewWindow()
   mMyNewWindow = new NewWindow(); // Be sure to destroy your window somewhere
   // ...

This is an example on how display a custom new window. There are a lot of ways to do this.

How to instantiate a File object in JavaScript?

Because this is javascript and dynamic you could define your own class that matches the File interface and use that instead.

I had to do just that with dropzone.js because I wanted to simulate a file upload and it works on File objects.

How to return XML in ASP.NET?

Below is the server side code that would call the handler and recieve the stream data and loads into xml doc

 Stream stream = null;
       **Create a web request with the specified URL**
        WebRequest myWebRequest = WebRequest.Create(@"http://localhost/XMLProvider/XMLProcessorHandler.ashx");
        **Senda a web request and wait for response.**
        WebResponse webResponse = myWebRequest.GetResponse();
        **Get the stream object from response object**
        stream = webResponse.GetResponseStream();

       XmlDocument xmlDoc = new XmlDocument();
      **Load stream data into xml**

Embed an External Page Without an Iframe?

You could load the external page with jquery:

<div id="testLoad"></div>
//would this help

Regex pattern for checking if a string starts with a certain substring?

For the extension method fans:

public static bool RegexStartsWith(this string str, params string[] patterns)
    return patterns.Any(pattern => 
       Regex.Match(str, "^("+pattern+")").Success);


var answer = str.RegexStartsWith("mailto","ftp","joe");
var answer2 = str.RegexStartsWith("mailto|ftp|joe");
bool startsWithWhiteSpace = "  does this start with space or tab?".RegexStartsWith(@"\s");

How to divide flask app into multiple py files?

Dividing the app into blueprints is a great idea. However, if this isn't enough, and if you want to then divide the Blueprint itself into multiple py files, this is also possible using the regular Python module import system, and then looping through all the routes that get imported from the other files.

I created a Gist with the code for doing this:

As far as I'm aware, this is the only feasible way to divide up a Blueprint at the moment. It's not possible to create "sub-blueprints" in Flask, although there's an issue open with a lot of discussion about this:

Also, even if it were possible (and it's probably do-able using some of the snippets from that issue thread), sub-blueprints may be too restrictive for your use case anyway - e.g. if you don't want all the routes in a sub-module to have the same URL sub-prefix.

Regex to match only letters

Use a character set: [a-zA-Z] matches one letter from A–Z in lowercase and uppercase. [a-zA-Z]+ matches one or more letters and ^[a-zA-Z]+$ matches only strings that consist of one or more letters only (^ and $ mark the begin and end of a string respectively).

If you want to match other letters than A–Z, you can either add them to the character set: [a-zA-ZäöüßÄÖÜ]. Or you use predefined character classes like the Unicode character property class \p{L} that describes the Unicode characters that are letters.

How to use PHP string in mySQL LIKE query?

You have the syntax wrong; there is no need to place a period inside a double-quoted string. Instead, it should be more like

$query = mysql_query("SELECT * FROM table WHERE the_number LIKE '$prefix%'");

You can confirm this by printing out the string to see that it turns out identical to the first case.

Of course it's not a good idea to simply inject variables into the query string like this because of the danger of SQL injection. At the very least you should manually escape the contents of the variable with mysql_real_escape_string, which would make it look perhaps like this:

$sql = sprintf("SELECT * FROM table WHERE the_number LIKE '%s%%'",
$query = mysql_query($sql);

Note that inside the first argument of sprintf the percent sign needs to be doubled to end up appearing once in the result.

Android how to use Environment.getExternalStorageDirectory()


Gives you the full path the SDCard. You can then do normal File I/O operations using standard Java.

Here's a simple example for writing a file:

String baseDir = Environment.getExternalStorageDirectory().getAbsolutePath();
String fileName = "myFile.txt";

// Not sure if the / is on the path or not
File f = new File(baseDir + File.separator + fileName);


Oops - you wanted an example for reading ...

String baseDir = Environment.getExternalStorageDirectory().getAbsolutePath();
String fileName = "myFile.txt";

// Not sure if the / is on the path or not
File f = new File(baseDir + File.Separator + fileName);
FileInputStream fiStream = new FileInputStream(f);

byte[] bytes;

// You might not get the whole file, lookup File I/O examples for Java; 

how to stop a running script in Matlab

If ctrl+c doesn't respond right away because your script is too long/complex, hold it.

The break command doesn't run when matlab is executing some of its deeper scripts, and either it won't log a ctrl sequence in the buffer, or it clears the buffer just before or just after it completes those pieces of code. In either case, when matlab returns to execute more of your script, it will recognize that you are holding ctrl+c and terminate.

For longer running programs, I usually try to find a good place to provide a status update and I always accompany that with some measure of time using tic and toc. Depending on what I am doing, I might use run time, segment time, some kind of average, etc...

For really long running programs, I found this to be exceptionally useful

but it looks like they have some newer functions for this too.

AJAX Mailchimp signup form integration

For anyone looking for a solution on a modern stack:

import jsonp from 'jsonp';
import queryString from 'query-string';

// formData being an object with your form data like:
// { EMAIL: '[email protected]' }

jsonp(`//${queryString.stringify(formData)}`, { param: 'c' }, (err, data) => {

How to access elements of a JArray (or iterate over them)

Update - I verified the below works. Maybe the creation of your JArray isn't quite right.

    public void TestJson()
        var jsonString = @"{""trends"": [
                ""name"": ""Croke Park II"",
                ""url"": """",
                ""promoted_content"": null,
                ""query"": ""%22Croke+Park+II%22"",
                ""events"": null
                ""name"": ""Siptu"",
                ""url"": """",
                ""promoted_content"": null,
                ""query"": ""Siptu"",
                ""events"": null
                ""name"": ""#HNCJ"",
                ""url"": """",
                ""promoted_content"": null,
                ""query"": ""%23HNCJ"",
                ""events"": null
                ""name"": ""Boston"",
                ""url"": """",
                ""promoted_content"": null,
                ""query"": ""Boston"",
                ""events"": null
                ""name"": ""#prayforboston"",
                ""url"": """",
                ""promoted_content"": null,
                ""query"": ""%23prayforboston"",
                ""events"": null
                ""name"": ""#TheMrsCarterShow"",
                ""url"": """",
                ""promoted_content"": null,
                ""query"": ""%23TheMrsCarterShow"",
                ""events"": null
                ""name"": ""#Raw"",
                ""url"": """",
                ""promoted_content"": null,
                ""query"": ""%23Raw"",
                ""events"": null
                ""name"": ""Iran"",
                ""url"": """",
                ""promoted_content"": null,
                ""query"": ""Iran"",
                ""events"": null
                ""name"": ""#gaa"",
                ""url"": """",
                ""promoted_content"": null,
                ""query"": ""gaa"",
                ""events"": null
                ""name"": ""Facebook"",
                ""url"": """",
                ""promoted_content"": null,
                ""query"": ""Facebook"",
                ""events"": null

        var twitterObject = JToken.Parse(jsonString);
        var trendsArray = twitterObject.Children<JProperty>().FirstOrDefault(x => x.Name == "trends").Value;

        foreach (var item in trendsArray.Children())
            var itemProperties = item.Children<JProperty>();
            //you could do a foreach or a linq here depending on what you need to do exactly with the value
            var myElement = itemProperties.FirstOrDefault(x => x.Name == "url");
            var myElementValue = myElement.Value; ////This is a JValue type

So call Children on your JArray to get each JObject in JArray. Call Children on each JObject to access the objects properties.

foreach(var item in yourJArray.Children())
    var itemProperties = item.Children<JProperty>();
    //you could do a foreach or a linq here depending on what you need to do exactly with the value
    var myElement = itemProperties.FirstOrDefault(x => x.Name == "url");
    var myElementValue = myElement.Value; ////This is a JValue type

Bash integer comparison

This script works!

if [[ ( "$#" < 1 ) || ( !( "$1" == 1 ) && !( "$1" == 0 ) ) ]] ; then
    echo this script requires a 1 or 0 as first parameter.
    echo "first parameter is $1"
    xinput set-prop 12 "Device Enabled" $0

But this also works, and in addition keeps the logic of the OP, since the question is about calculations. Here it is with only arithmetic expressions:

if (( $# )) && (( $1 == 0 || $1 == 1 )); then
    echo "first parameter is $1"
    xinput set-prop 12 "Device Enabled" $0
    echo this script requires a 1 or 0 as first parameter.

The output is the same1:

$ ./ 
this script requires a 1 or 0 as first parameter.

$ ./ 0
first parameter is 0

$ ./ 1
first parameter is 1

$ ./ 2
this script requires a 1 or 0 as first parameter.

[1] the second fails if the first argument is a string

PANIC: Broken AVD system path. Check your ANDROID_SDK_ROOT value

After quite some time trying other Googled "solutions", the only thing that worked for me, after setting the ANDROID_SDK_ROOT environment variable on Windows, and also adding and removing ANDROID_HOME and ANDROID_SDK_HOME variables, was Xerox23's answer - editing the AVD's config.ini to hardcode the value of ANDROID_SDK_ROOT into the image.sysdir.1 property.

This was using Android Studio 3.0.1 and emulator 26.1.4, launching the virtual device from the AVD Manager from within Android Studio.

Microsoft.ACE.OLEDB.12.0 provider is not registered

I'm having same problem. I try to install office 2010 64bit on windows 7 64 bit and then install 2007 Office System Driver : Data Connectivity Components.

after that, visual studio 2008 can opens a connection to an MS-Access 2007 database file.

ASP.NET MVC View Engine Comparison

I know this doesn't really answer your question, but different View Engines have different purposes. The Spark View Engine, for example, aims to rid your views of "tag soup" by trying to make everything fluent and readable.

Your best bet would be to just look at some implementations. If it looks appealing to the intent of your solution, try it out. You can mix and match view engines in MVC, so it shouldn't be an issue if you decide to not go with a specific engine.

Couldn't load memtrack module Logcat Error

I faced the same problem but When I changed the skin of AVD device to HVGA, it worked.

How to remove and clear all localStorage data

It only worked for me in Firefox when accessing it from the window object.


window.onload = function()

Oracle Convert Seconds to Hours:Minutes:Seconds

For greater than 24 hours you can include days with the following query. The returned format is days:hh24:mi:ss

select trunc(trunc(sysdate) + numtodsinterval(9999999, 'second')) - trunc(sysdate) || ':' || to_char(trunc(sysdate) + numtodsinterval(9999999, 'second'), 'hh24:mi:ss') from dual;


Declaring a variable and setting its value from a SELECT query in Oracle

For storing a single row output into a variable from the select into query :

declare v_username varchare(20); SELECT username into v_username FROM users WHERE user_id = '7';

this will store the value of a single record into the variable v_username.

For storing multiple rows output into a variable from the select into query :

you have to use listagg function. listagg concatenate the resultant rows of a coloumn into a single coloumn and also to differentiate them you can use a special symbol. use the query as below SELECT listagg(username || ',' ) within group (order by username) into v_username FROM users;

Order by descending date - month, day and year

what is the type of the field EventDate, since the ordering isn't correct i assume you don't have it set to some Date/Time representing type, but a string. And then the american way of writing dates is nasty to sort

How to re-render flatlist?

Use the extraData property on your FlatList component.

As the documentation states:

By passing extraData={this.state} to FlatList we make sure FlatList will re-render itself when the state.selected changes. Without setting this prop, FlatList would not know it needs to re-render any items because it is also a PureComponent and the prop comparison will not show any changes.

How to update Ruby Version 2.0.0 to the latest version in Mac OSX Yosemite?

brew install rbenv ruby-build

Add rbenv to bash so that it loads every time you open a terminal

echo 'if which rbenv > /dev/null; then eval "$(rbenv init -)"; fi' >> ~/.bash_profile

source ~/.bash_profile

Install Ruby

rbenv install 2.6.5

rbenv global 2.6.5

ruby -v

Link to the source page

jQuery click events not working in iOS

You should bind the tap event, the click does not exist on mobile safari or in the UIWbview. You can also use this polyfill ,to avoid the 300ms delay when a link is touched.

How to check Oracle patches are installed?

Maybe you need "sys." before:

select * from sys.registry$history;

Get Today's date in Java at midnight time

Here is a Java 8 way to get UTC Midnight in millis

ZonedDateTime utcTime =;
long todayMidnight = utcTime.toLocalDate().atStartOfDay().toEpochSecond(ZoneOffset.UTC) * 1000;

Toggle display:none style with JavaScript

you can do this easily by using jquery using .css property... try this one:

Repeat command automatically in Linux

while true; do
    sleep 5
    ls -l

Which MySQL datatype to use for an IP address?

For IPv4 addresses, you can use VARCHAR to store them as strings, but also look into storing them as long integesrs INT(11) UNSIGNED. You can use MySQL's INET_ATON() function to convert them to integer representation. The benefit of this is it allows you to do easy comparisons on them, like BETWEEN queries

INET_ATON() MySQL function

How to count down in for loop?

In python, when you have an iterable, usually you iterate without an index:

letters = 'abcdef' # or a list, tupple or other iterable
for l in letters:

If you need to traverse the iterable in reverse order, you would do:

for l in letters[::-1]:

When for any reason you need the index, you can use enumerate:

for i, l in enumerate(letters, start=1): #start is 0 by default

You can enumerate in reverse order too...

for i, l in enumerate(letters[::-1])


Usually when we traverse an iterable we do it to apply the same procedure or function to each element. In these cases, it is better to use map:

If we need to capitilize each letter:

map(str.upper, letters)

Or get the Unicode code of each letter:

map(ord, letters)

Curl command without using cache

I know this is an older question, but I wanted to post an answer for users with the same question:

curl -H 'Cache-Control: no-cache'

This curl command servers in its header request to return non-cached data from the web server.

Resize image proportionally with CSS?


transform: scale(0.5, 0.5);
-ms-transform: scale(0.5, 0.5);
-webkit-transform: scale(0.5, 0.5);

Angular2 Material Dialog css, dialog size

With current version of Angular Material (6.4.7) you can use a custom class:

let dialogRef =, {
  panelClass: 'my-class'

Now put your class somewhere global (haven't been able to make this work elsewhere), e.g. in styles.css:

.my-class .mat-dialog-container{
  height: 400px;
  width: 600px;
  border-radius: 10px;
  background: lightcyan;
  color: #039be5;


Multiple IF statements between number ranges

It's a little tricky because of the nested IFs but here is my answer (confirmed in Google Spreadsheets):

=IF(AND(A2>=0,    A2<500),  "Less than 500", 
 IF(AND(A2>=500,  A2<1000), "Between 500 and 1000", 
 IF(AND(A2>=1000, A2<1500), "Between 1000 and 1500", 
 IF(AND(A2>=1500, A2<2000), "Between 1500 and 2000", "Undefined"))))

Lowercase and Uppercase with jQuery

If it's just for display purposes, you can render the text as upper or lower case in pure CSS, without any Javascript using the text-transform property:

.myclass {
    text-transform: lowercase;

See for more info.

However, note that this doesn't actually change the value to lower case; it just displays it that way. This means that if you examine the contents of the element (ie using Javascript), it will still be in its original format.

How to get full width in body element

You should set body and html to position:fixed;, and then set right:, left:, top:, and bottom: to 0;. That way, even if content overflows it will not extend past the limits of the viewport.

For example:

    <div id="wrapper"></div>


html, body, {

JS Fiddle Example

Caveat: Using this method, if the user makes their window smaller, content will be cut off.

Best Practices for mapping one object to another

/// <summary>
/// map properties
/// </summary>
/// <param name="sourceObj"></param>
/// <param name="targetObj"></param>
private void MapProp(object sourceObj, object targetObj)
    Type T1 = sourceObj.GetType();
    Type T2 = targetObj.GetType();

    PropertyInfo[] sourceProprties = T1.GetProperties(BindingFlags.Instance | BindingFlags.Public);
    PropertyInfo[] targetProprties = T2.GetProperties(BindingFlags.Instance | BindingFlags.Public);

   foreach (var sourceProp in sourceProprties)
       object osourceVal = sourceProp.GetValue(sourceObj, null);
       int entIndex = Array.IndexOf(targetProprties, sourceProp);
       if (entIndex >= 0)
           var targetProp = targetProprties[entIndex];
           targetProp.SetValue(targetObj, osourceVal);

Execute function after Ajax call is complete

Append .done() to your ajax request.

  url: "test.html",
  context: document.body
}).done(function() { //use this

See the JQuery Doc for .done()

Can't install Scipy through pip

use the wheel file to install download from here install

pip install c:\jjjj\ggg\fdadf.whl

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

just cut the string using split (the easy way):

var myString = "http://localhost/dms/mduserSecurity/UIL/index.php?menu=true&submenu=true&pcode=1235"
var mySplitResult = myString.split("?");

How to make layout with rounded corners..?

Here's a copy of a XML file to create a drawable with a white background, black border and rounded corners:

 <?xml version="1.0" encoding="UTF-8"?> 
    <shape xmlns:android=""> 
        <solid android:color="#ffffffff"/>    

        <stroke android:width="3dp"

        <padding android:left="1dp"

        <corners android:bottomRightRadius="7dp" android:bottomLeftRadius="7dp" 
         android:topLeftRadius="7dp" android:topRightRadius="7dp"/> 

save it as a xml file in the drawable directory, Use it like you would use any drawable background(icon or resource file) using its resource name (R.drawable.your_xml_name)

CSS: Background image and padding

You can achieve your results with two methods:-

First Method define position values:-


 <li>Hello world</li>



ul li{
    border:1px solid orange;
    background: url("") no-repeat 90% 5px;

ul li:hover{
    background: yellow url("") no-repeat 90% 5px;

First Demo:-

Second Method by CSS :before:after Selectors


<li>Hello world</li>



ul li{
    border:1px solid orange;

ul li:after {
    content: " ";
    padding-right: 16px;
    background: url("") no-repeat center right;

ul li:hover {

ul li:hover:after {
    content: " ";
    padding-right: 16px;
    background: url("") no-repeat center right;

Second Demo:-

Moving from position A to position B slowly with animation

You can animate it after the fadeIn completes using the callback as shown below:

  $(this).animate({'top': '-=30px'},'slow');

C++ vector's insert & push_back difference

The biggest difference is their functionality. push_back always puts a new element at the end of the vector and insert allows you to select new element's position. This impacts the performance. vector elements are moved in the memory only when it's necessary to increase it's length because too little memory was allocated for it. On the other hand insert forces to move all elements after the selected position of a new element. You simply have to make a place for it. This is why insert might often be less efficient than push_back.

Laravel 5 route not defined, while it is?

I'm using Laravel 5.7 and tried all of the above answers but nothing seemed to be hitting the spot.

For me, it was a rather simple fix by removing the cache files created by Laravel.
It seemed that my changes were not being reflected, and therefore my application wasn't seeing the routes.

A bit overkill, but I decided to reset all my cache at the same time using the following commands:

php artisan route:clear
php artisan view:clear
php artisan cache:clear

The main one here is the first command which will delete the bootstrap/cache/routes.php file.
The second command will remove the cached files for the views that are stored in the storage/framework/cache folder.
Finally, the last command will clear the application cache.

Base64 length calculation?

Seems to me that the right formula should be:

n64 = 4 * (n / 3) + (n % 3 != 0 ? 4 : 0)

How to shutdown my Jenkins safely?

You can kill Jenkins safely. It will catch SIGTERM and SIGINT and perform an orderly shutdown. However, if Jenkins was in the middle of building something, it will abort the builds and they will show up gray in the status display.

If you want to avoid this, you must put Jenkins into shutdown mode to prevent it from starting new builds and wait until currently running builds are done before killing Jenkins.

You can also use the Jenkins command line interface and tell Jenkins to safe-shutdown, which does the same. You can find more info on Jenkins cli at http://YOURJENKINS/cli

'IF' in 'SELECT' statement - choose output value based on column values

SELECT id, amount
FROM report
WHERE type='P'


SELECT id, (amount * -1) AS amount
FROM report
WHERE type = 'N'


What causes an HTTP 405 "invalid method (HTTP verb)" error when POSTing a form to PHP on IIS?

I had this issue with a facebook application that I was developing for a fan page tab. If anyone faces this issue with a facebook application then


2-select the application that you are developing

3-make sure that all the link to your application has tailing slash /

my issue was in the>Apps->MYAPPNAME->settings->Page Tab->Secure Page Tab URL, Page Tab Edit URL, Page Tab URL hope this will help

Solr vs. ElasticSearch

I see some of the above answers are now a bit out of date. From my perspective, and I work with both Solr(Cloud and non-Cloud) and ElasticSearch on a daily basis, here are some interesting differences:

  • Community: Solr has a bigger, more mature user, dev, and contributor community. ES has a smaller, but active community of users and a growing community of contributors
  • Maturity: Solr is more mature, but ES has grown rapidly and I consider it stable
  • Performance: hard to judge. I/we have not done direct performance benchmarks. A person at LinkedIn did compare Solr vs. ES vs. Sensei once, but the initial results should be ignored because they used non-expert setup for both Solr and ES.
  • Design: People love Solr. The Java API is somewhat verbose, but people like how it's put together. Solr code is unfortunately not always very pretty. Also, ES has sharding, real-time replication, document and routing built-in. While some of this exists in Solr, too, it feels a bit like an after-thought.
  • Support: there are companies providing tech and consulting support for both Solr and ElasticSearch. I think the only company that provides support for both is Sematext (disclosure: I'm Sematext founder)
  • Scalability: both can be scaled to very large clusters. ES is easier to scale than pre-Solr 4.0 version of Solr, but with Solr 4.0 that's no longer the case.

For more thorough coverage of Solr vs. ElasticSearch topic have a look at . This is the first post in the series of posts from Sematext doing direct and neutral Solr vs. ElasticSearch comparison. Disclosure: I work at Sematext.

CSS customized scroll bar in div

Webkit scrollbar doesnt support on most of the browers.

Supports on CHROME

Here is a demo for webkit scrollbar Webkit Scrollbar DEMO

If you are looking for more examples Check this More Examples

Another Method is Jquery Scroll Bar Plugin

It supports on all browsers and easy to apply

Download the plugin from Download Here

How to use and for more options CHECK THIS


Delete/Reset all entries in Core Data?

you can also find all the entity names, and delete them by name. Its a longer version but works well, that way you dont have to work with persistence store

 - (void)clearCoreData
NSError *error;
NSEntityDescription *des = [NSEntityDescription entityForName:@"Any_Entity_Name" inManagedObjectContext:_managedObjectContext];
NSManagedObjectModel *model = [des managedObjectModel];
NSArray *entityNames = [[model entities] valueForKey:@"name"];

for (NSString *entityName in entityNames){

    NSFetchRequest *deleteAll = [NSFetchRequest fetchRequestWithEntityName:entityName];
    NSArray *matches = [self.database.managedObjectContext executeFetchRequest:deleteAll error:&error];

    if (matches.count > 0){
        for (id obj in matches){

            [_managedObjectContext deleteObject:obj];
       [self.database.managedObjectContext save:&error];

for "Any_Entity_Name" just give any one of your entity's name, we only need to figure out the entity description your entities are within. ValueForKey@"name" will return all the entity names. Finally, dont forget to save.

Big-O summary for Java Collections Framework implementations?

The book Java Generics and Collections has this information (pages: 188, 211, 222, 240).

List implementations:

                      get  add  contains next remove(0) iterator.remove
ArrayList             O(1) O(1) O(n)     O(1) O(n)      O(n)
LinkedList            O(n) O(1) O(n)     O(1) O(1)      O(1)
CopyOnWrite-ArrayList O(1) O(n) O(n)     O(1) O(n)      O(n)

Set implementations:

                      add      contains next     notes
HashSet               O(1)     O(1)     O(h/n)   h is the table capacity
LinkedHashSet         O(1)     O(1)     O(1) 
CopyOnWriteArraySet   O(n)     O(n)     O(1) 
EnumSet               O(1)     O(1)     O(1) 
TreeSet               O(log n) O(log n) O(log n)
ConcurrentSkipListSet O(log n) O(log n) O(1)

Map implementations:

                      get      containsKey next     Notes
HashMap               O(1)     O(1)        O(h/n)   h is the table capacity
LinkedHashMap         O(1)     O(1)        O(1) 
IdentityHashMap       O(1)     O(1)        O(h/n)   h is the table capacity 
EnumMap               O(1)     O(1)        O(1) 
TreeMap               O(log n) O(log n)    O(log n) 
ConcurrentHashMap     O(1)     O(1)        O(h/n)   h is the table capacity 
ConcurrentSkipListMap O(log n) O(log n)    O(1)

Queue implementations:

                      offer    peek poll     size
PriorityQueue         O(log n) O(1) O(log n) O(1)
ConcurrentLinkedQueue O(1)     O(1) O(1)     O(n)
ArrayBlockingQueue    O(1)     O(1) O(1)     O(1)
LinkedBlockingQueue   O(1)     O(1) O(1)     O(1)
PriorityBlockingQueue O(log n) O(1) O(log n) O(1)
DelayQueue            O(log n) O(1) O(log n) O(1)
LinkedList            O(1)     O(1) O(1)     O(1)
ArrayDeque            O(1)     O(1) O(1)     O(1)
LinkedBlockingDeque   O(1)     O(1) O(1)     O(1)

The bottom of the javadoc for the java.util package contains some good links:

Package php5 have no installation candidate (Ubuntu 16.04)

Ubuntu 16.04 comes with PHP7 as the standard, so there are no PHP5 packages

However if you like you can add a PPA to get those packages anyways:

Remove all the stock php packages

List installed php packages with dpkg -l | grep php| awk '{print $2}' |tr "\n" " " then remove unneeded packages with sudo aptitude purge your_packages_here or if you want to directly remove them all use :

sudo aptitude purge `dpkg -l | grep php| awk '{print $2}' |tr "\n" " "`

Add the PPA

sudo add-apt-repository ppa:ondrej/php

Install your PHP Version

sudo apt-get update
sudo apt-get install php5.6

You can install php5.6 modules too ..

Verify your version

sudo php -v

Based on (thanks @AhmedJerbi)

How can I control the speed that bootstrap carousel slides in items?

You need to set interval in the main DIV as data-interval tag. The it will work fine and you can give different time to different slides.

<div class="carousel" data-interval="5000">

I can't install intel HAXM

None of the suggestions worked on their own.

Here is what worked for me: chmod -R 777 $ANDROID_HOME

Then try to install it via android studio -> sdk manager. If its not there, reinstall latest version of Android studio over your current installation. HAXM will show up in SDK manager after that.

If you do not have ANDROID_HOME set, then YOU are part of the problem. The value of it can be found inside Android Studio project structure. On MAC, just type CMD ; and look at SDK Location on left.

Simply run chmod -R 775

Using Chrome, how to find to which events are bound to an element

For Chrome Version 52.0.2743.116:

  1. In Chrome's Developer Tools, bring up the 'Search' panel by hitting Ctrl+Shift+F.

  2. Type in the name of the element you're trying to find.

Results for binded elements should appear in the panel and state the file they're located in.

send checkbox value in PHP form


$name = $_POST['name']; 
$email_address = $_POST['email']; 
$message = $_POST['tel']; 


$name = $_POST['name']; 
$email_address = $_POST['email']; 
$message = $_POST['tel'];
if (isset($_POST['newsletter'])) {
  $checkBoxValue = "yes";
} else {
  $checkBoxValue = "no";

then replace this line of code:

$email_body = "You have received a new message. ".
    " Here are the details:\n Name: $name \n Email: $email_address \n Tel \n $message\n Newsletter \n $newsletter"


$email_body = "You have received a new message. ".
    " Here are the details:\n Name: $name \n Email: $email_address \n Tel \n $message\n Newsletter \n $newsletter";

How to store a dataframe using Pandas

The easiest way is to pickle it using to_pickle:

df.to_pickle(file_name)  # where to save it, usually as a .pkl

Then you can load it back using:

df = pd.read_pickle(file_name)

Note: before 0.11.1 save and load were the only way to do this (they are now deprecated in favor of to_pickle and read_pickle respectively).

Another popular choice is to use HDF5 (pytables) which offers very fast access times for large datasets:

import pandas as pd
store = pd.HDFStore('store.h5')

store['df'] = df  # save it
store['df']  # load it

More advanced strategies are discussed in the cookbook.

Since 0.13 there's also msgpack which may be be better for interoperability, as a faster alternative to JSON, or if you have python object/text-heavy data (see this question).

How to write a SQL DELETE statement with a SELECT statement in the WHERE clause?

You need to identify the primary key in TableA in order to delete the correct record. The primary key may be a single column or a combination of several columns that uniquely identifies a row in the table. If there is no primary key, then the ROWID pseudo column may be used as the primary key.

    FROM tableA q
      INNER JOIN tableB u on (u.qlabel = q.entityrole AND u.fieldnum = q.fieldnum) 
    WHERE (LENGTH(q.memotext) NOT IN (8,9,10) OR q.memotext NOT LIKE '%/%/%')
      AND (u.FldFormat = 'Date'));

How to use a TRIM function in SQL Server


            foo   bar
        Foo           Bar        


PRINT '[' + @Str + ']'


WHILE ((@StrPrv <> @Str) AND (@Str IS NOT NULL)) BEGIN
    SET @StrPrv = @Str

    -- Beginning
    IF EXISTS (SELECT 1 WHERE @Str LIKE '[' + CHAR(13) + CHAR(10) + CHAR(9) + ']%')
        SET @Str = LTRIM(RIGHT(@Str, LEN(@Str) - 1))

    -- Ending
    IF EXISTS (SELECT 1 WHERE @Str LIKE '%[' + CHAR(13) + CHAR(10) + CHAR(9) + ']')
        SET @Str = RTRIM(LEFT(@Str, LEN(@Str) - 1))

PRINT '[' + @Str + ']'


            foo   bar
        Foo           Bar        

[foo   bar
        Foo           Bar]

Using fnTrim


SELECT dbo.fnTrim(colName)

database vs. flat files

Don't build it if you can buy it.

I heard this quote recently, and it really seems fitting as a guide line. Ask yourself this... How much time was spent working on the file handling portion of your app? I suspect a fair amount of time was spent optimizing this code for performance. If you had been using a relational database all along, you would have spent considerably less time handling this portion of your application. You would have had more time for the true "business" aspect of your app.

How do I set up cron to run a file just once at a specific time?

You could put a crontab file in /etc/cron.d which would run a script that would run your command and then delete the crontab file in /etc/cron.d. Of course, that means your script would need to run as root.

How can I pad a String in Java?

Here is another way to pad to the right:

// put the number of spaces, or any character you like, in your paddedString

String paddedString = "--------------------";

String myStringToBePadded = "I like donuts";

myStringToBePadded = myStringToBePadded + paddedString.substring(myStringToBePadded.length());

myStringToBePadded = "I like donuts-------";

connecting to mysql server on another PC in LAN

actually you shouldn't specify port in the host name. Mysql has special option for port (if port differs from default)

kind of

mysql --host= --port=3306

Translating touch events from Javascript to jQuery

$(window).on("touchstart", function(ev) {
    var e = ev.originalEvent;

I know it been asked a long time ago, but I thought a concrete example might help.

How to pass a datetime parameter?

As a matter of fact, specifying parameters explicitly as ?date='fulldatetime' worked like a charm. So this will be a solution for now: don't use commas, but use old GET approach.

How to move Jenkins from one PC to another

Jenkins Server Automation:

Step 1:

Set up a repository to store the Jenkins home (jobs, configurations, plugins, etc.) in a GitLab local or on GitHub private repository and keep it updated regularly by pushing any new changes to Jenkins jobs, plugins, etc.

Step 2:

Configure a Puppet host-group/role for Jenkins that can be used to spin up new Jenkins servers. Do all the basic configuration in a Puppet recipe and make sure it installs the latest version of Jenkins and sets up a separate directory/mount for JENKINS_HOME.

Step 3:

Spin up a new machine using the Jenkins-puppet configuration above. When everything is installed, grab/clone the Jenkins configuration from the Git repository to the Jenkins home direcotry and restart Jenkins.

Step 4:

Go to the Jenkins URL, Manage Jenkins ? Manage Plugins and update all the plugins that require an update.


You can use Docker Swarm or Kubernetes to auto-scale the slave nodes.

How to send a POST request in Go?

I know this is old but this answer came up in search results. For the next guy - the proposed and accepted answer works, however the code initially submitted in the question is lower-level than it needs to be. Nobody got time for that.

//one-line post request/response...
response, err := http.PostForm(APIURL, url.Values{
    "ln": {c.ln},
    "ip": {c.ip},
    "ua": {}})

//okay, moving on...
if err != nil {
  //handle postform error

defer response.Body.Close()
body, err := ioutil.ReadAll(response.Body)

if err != nil {
  //handle read response error

fmt.Printf("%s\n", string(body))

What is the result of % in Python?

The % (modulo) operator yields the remainder from the division of the first argument by the second. The numeric arguments are first converted to a common type.

3 + 2 + 1 - 5 + 4 % 2 - 1 / 4 + 6 = 7

This is based on operator precedence.

How to get the mysql table columns data type?

Most answers are duplicates, it might be useful to group them. Basically two simple options have been proposed.

First option

The first option has 4 different aliases, some of which are quite short :

EXPLAIN db_name.table_name;
DESCRIBE db_name.table_name;
SHOW FIELDS FROM db_name.table_name;
SHOW COLUMNS FROM db_name.table_name;

(NB : as an alternative to db_name.table_name, one can use a second FROM : db_name FROM table_name).

This gives something like :

| Field            | Type         | Null | Key | Default | Extra |
| product_id       | int(11)      | NO   | PRI | NULL    |       |
| name             | varchar(255) | NO   | MUL | NULL    |       |
| description      | text         | NO   |     | NULL    |       |
| meta_title       | varchar(255) | NO   |     | NULL    |       |

Second option

The second option is a bit longer :

  TABLE_SCHEMA = 'db_name'
  TABLE_NAME = 'table_name';

It is also less talkative :

| column_name      | DATA_TYPE |
| product_id       | int       |
| name             | varchar   |
| description      | text      |
| meta_title       | varchar   |

It has the advantage of allowing selection per column, though, using AND COLUMN_NAME = 'column_name' (or like).

Waiting for another flutter command to release the startup lock

For me, the issue's root cause on my Mac device was a version of the flock binary it was not expecting. Removing it from the path did the trick; probably a BSD vs GNU syntax issue.

How do I restart nginx only after the configuration test was successful on Ubuntu?

You can reload using /etc/init.d/nginx reload and sudo service nginx reload

If nginx -t throws some error then it won't reload

so use && to run both at a same time


nginx -t && /etc/init.d/nginx reload

ValueError: Wrong number of items passed - Meaning and suggestions?

In general, the error ValueError: Wrong number of items passed 3, placement implies 1 suggests that you are attempting to put too many pigeons in too few pigeonholes. In this case, the value on the right of the equation

results['predictedY'] = predictedY

is trying to put 3 "things" into a container that allows only one. Because the left side is a dataframe column, and can accept multiple items on that (column) dimension, you should see that there are too many items on another dimension.

Here, it appears you are using sklearn for modeling, which is where gaussian_process.GaussianProcess() is coming from (I'm guessing, but correct me and revise the question if this is wrong).

Now, you generate predicted values for y here:

predictedY, MSE = gp.predict(testX, eval_MSE = True)

However, as we can see from the documentation for GaussianProcess, predict() returns two items. The first is y, which is array-like (emphasis mine). That means that it can have more than one dimension, or, to be concrete for thick headed people like me, it can have more than one column -- see that it can return (n_samples, n_targets) which, depending on testX, could be (1000, 3) (just to pick numbers). Thus, your predictedY might have 3 columns.

If so, when you try to put something with three "columns" into a single dataframe column, you are passing 3 items where only 1 would fit.

Vim and Ctags tips and tricks

Another useful plugin for C development is cscope Just as Ctags lets you jump to definitions, Cscope jumps to the calling functions.

If you have cscope in your ~/bin/ directory, add the following to your .vimrc and use g^] to go to the calling function (see :help cscope).

if has("cscope")
    set csprg=~/bin/cscope
    set csto=0
    set cst
    set nocsverb
    " add any database in current directory
    if filereadable("cscope.out")
        cs add cscope.out
        " else add database pointed to by environment
    elseif $CSCOPE_DB != ""
        cs add $CSCOPE_DB

Almost forgot... Just as ctags - you have to generate (and periodically update) the database. I use the following script

select_files > cscope.files
ctags -L cscope.files
ctags -e -L cscope.files
cscope -ub -i cscope.files

Where 'select_files' is another script that extracts the list of C and header files from the Makefile. This way I index only the files actually used by the project.

Bootstrap carousel width and height

I know this is an older post but Bootstrap is still alive and kicking!

Slightly different to @Eduardo's post, I had to modify:

#myCarousel.carousel.slide {
    width: 100%; 
    max-width: 400px; !important

When I only modified .carousel-inner {}, the actual image was fixed size but the left/right controls were displaying incorrectly off to the side of the div.

How to pattern match using regular expression in Scala?

Note that the approach from @AndrewMyers's answer matches the entire string to the regular expression, with the effect of anchoring the regular expression at both ends of the string using ^ and $. Example:

scala> val MY_RE = "(foo|bar).*".r
MY_RE: scala.util.matching.Regex = (foo|bar).*

scala> val result = "foo123" match { case MY_RE(m) => m; case _ => "No match" }
result: String = foo

scala> val result = "baz123" match { case MY_RE(m) => m; case _ => "No match" }
result: String = No match

scala> val result = "abcfoo123" match { case MY_RE(m) => m; case _ => "No match" }
result: String = No match

And with no .* at the end:

scala> val MY_RE2 = "(foo|bar)".r
MY_RE2: scala.util.matching.Regex = (foo|bar)

scala> val result = "foo123" match { case MY_RE2(m) => m; case _ => "No match" }
result: String = No match

Powershell Log Off Remote Session

Here's a great scripted solution for logging people out remotely or locally. I'm using qwinsta to get session information and building an array out of the given output. This makes it really easy to iterate through each entry and log out only the actual users, and not the system or RDP listener itself which usually just throws an access denied error anyway.

$serverName = "Name of server here OR localhost"
$sessions = qwinsta /server $serverName| ?{ $_ -notmatch '^ SESSIONNAME' } | %{
$item = "" | Select "Active", "SessionName", "Username", "Id", "State", "Type", "Device"
$item.Active = $_.Substring(0,1) -match '>'
$item.SessionName = $_.Substring(1,18).Trim()
$item.Username = $_.Substring(19,20).Trim()
$item.Id = $_.Substring(39,9).Trim()
$item.State = $_.Substring(48,8).Trim()
$item.Type = $_.Substring(56,12).Trim()
$item.Device = $_.Substring(68).Trim()

foreach ($session in $sessions){
    if ($session.Username -ne "" -or $session.Username.Length -gt 1){
        logoff /server $serverName $session.Id

In the first line of this script give $serverName the appropriate value or localhost if running locally. I use this script to kick users before an automated process attempts to move some folders around. Prevents "file in use" errors for me. Another note, this script will have to be ran as an administrator user otherwise you can get accessed denied trying to log someone out. Hope this helps!

how to call url of any other website in php

Check out the PHP cURL functions. They should do what you want.

Or if you just want a simple URL GET then:

$lines = file('');

How to Convert string "07:35" (HH:MM) to TimeSpan

You can convert the time using the following code.

TimeSpan _time = TimeSpan.Parse("07:35");

But if you want to get the current time of the day you can use the following code:

TimeSpan _CurrentTime = DateTime.Now.TimeOfDay;

The result will be:


With a object cantain the Hours, Minutes, Seconds, Ticks and etc.

Better way to shuffle two numpy arrays in unison

you can make an array like:

s = np.arange(0, len(a), 1)

then shuffle it:


now use this s as argument of your arrays. same shuffled arguments return same shuffled vectors.

x_data = x_data[s]
x_label = x_label[s]

CSS body background image fixed to full screen even when zooming in/out

You can do quite a lot with plain css...the css property background-size can be set to a number of things as well as just cover as Ranjith pointed out.

The background-size: cover setting scales the image to cover the entire screen but may mean that some of the image is off screen if the aspect ratio of the screen and image are different.

A good alternative is background-size: contain which resizes the background image to fit the smaller of width and height, ensuring that the whole image is visible but may lead to letterboxing if the aspect ratios are different.

For example:

body {
      background: url(/images/bkgd.png) no-repeat rgb(30,30,30) fixed center center;
      background-size: contain;

The other options that I find less useful are: background-size: length <widthpx> <heightpx> which sets the absolute size of the background image. background-size: percentage <width> <height> background image is a percentage of the window size. (see's page)

Finding what branch a Git commit came from

Aside from searching through all of the tree until you find a matching hash, no.

Install Application programmatically on Android

The solutions provided to this question are all applicable to targetSdkVersion s of 23 and below. For Android N, i.e. API level 24, and above, however, they do not work and crash with the following Exception:

android.os.FileUriExposedException: file:///storage/emulated/0/... exposed beyond app through Intent.getData()

This is due to the fact that starting from Android 24, the Uri for addressing the downloaded file has changed. For instance, an installation file named appName.apk stored on the primary external filesystem of the app with package name com.example.test would be as


for API 23 and below, whereas something like


for API 24 and above.

More details on this can be found here and I am not going to go through it.

To answer the question for targetSdkVersion of 24 and above, one has to follow these steps: Add the following to the AndroidManifest.xml:


2. Add the following paths.xml file to the xml folder on res in src, main:

<?xml version="1.0" encoding="utf-8"?>
<paths xmlns:android="">

The pathName is that shown in the exemplary content uri example above and pathValue is the actual path on the system. It would be a good idea to put a "." (without quotes) for pathValue in the above if you do not want to add any extra subdirectory.

  1. Write the following code to install the apk with the name appName.apk on the primary external filesystem:

    File directory = context.getExternalFilesDir(null);
    File file = new File(directory, fileName);
    Uri fileUri = Uri.fromFile(file);
    if (Build.VERSION.SDK_INT >= 24) {
        fileUri = FileProvider.getUriForFile(context, context.getPackageName(),
    Intent intent = new Intent(Intent.ACTION_VIEW, fileUri);
    intent.putExtra(Intent.EXTRA_NOT_UNKNOWN_SOURCE, true);
    intent.setDataAndType(fileUri, "application/" + ".package-archive");

No permission is also necessary when writing to your own app's private directory on the external filesystem.

I have written an AutoUpdate library here in which I have used the above.

VBScript: Using WScript.Shell to Execute a Command Line Program That Accesses Active Directory

The issue turned out to be certificate-related. The WCF service called by the console app uses an X509 cert for authentication, which is installed on the servers that this script is hosted and run from.

On other servers, where the same services are consumed, the certificates were configured as follows:

winhttpcertcfg.exe -g -c LOCAL_MACHINE\My -s "certificate-name" -a "NETWORK SERVICE"

As they ran within the context of IIS. However, when the script was being run as it would in production, it's under the context of the user themselves. So, the script needed to be modified to the following:

winhttpcertcfg.exe -g -c LOCAL_MACHINE\My -s "certificate-name" -a "USERS"

Once that change was made, all was well. Thanks to everyone who offered assistance.

Search for all files in project containing the text 'querystring' in Eclipse

press Ctrl + H . Then choose "File Search" tab.

additional search options

search for resources: Ctrl + Shift + R

search for Java types: Ctrl + Shift + T

Why does Boolean.ToString output "True" and not "true"

It's simple code to convert that to all lower case.

Not so simple to convert "true" back to "True", however.


is what I use for xml output.

What is LD_LIBRARY_PATH and how to use it?

LD_LIBRARY_PATH is Linux specific and is an environment variable pointing to directories where the dynamic loader should look for shared libraries.

Try to add the directory where your .dll is in the PATH variable. Windows will automatically look in the directories listet in this environment variable. LD_LIBRARY_PATH probably won't solve the problem (unless the JVM uses it - I do not know about that).

EF Migrations: Rollback last applied migration?

In EF Core you can enter the command Remove-Migration in the package manager console after you've added your erroneous migration.

The console suggests you do so if your migration could involve a loss of data:

An operation was scaffolded that may result in the loss of data. Please review the migration for accuracy. To undo this action, use Remove-Migration.

Checking if an Android application is running in the background

Since it isn't already mentioned, I will suggest the readers to explore ProcessLifecycleOwner available through Android Architecture components

Javascript Array Alert

If you want to see the array as an array, you can say


instead of all those document.writes.

However, if you want to display them cleanly, one per line, in your popup, do this:


Font Awesome not working, icons showing as squares

It wasn't working for me because I had Allow from none directive for the root directory in my apache config. Here's how I got it to work...

My directory structure:


where my index.html has:

<link rel="stylesheet" href="../font-awesome/4.4.0/css/font-awesome.min.css">

I chose to continue to disallow access to my root and instead added another directory entry in my apache config for root/font-awesome/

<Directory "/path/root/font-awesome/">
    Allow from all

How to execute function in SQL Server 2008

It looks like there's something else called Afisho_rankimin in your DB so the function is not being created. Try calling your function something else. E.g.

CREATE FUNCTION dbo.Afisho_rankimin1(@emri_rest int)
       Declare @rankimi int
       Select @rankimi=dbo.RESTORANTET.Rankimi
       Where  dbo.RESTORANTET.ID_Rest=@emri_rest
       RETURN @rankimi

Note that you need to call this only once, not every time you call the function. After that try calling

SELECT dbo.Afisho_rankimin1(5) AS Rankimi 

What are pipe and tap methods in Angular tutorial?

You are right, the documentation lacks of those methods. However when I dug into rxjs repository, I found nice comments about tap (too long to paste here) and pipe operators:

   * Used to stitch together functional operators into a chain.
   * @method pipe
   * @return {Observable} the Observable result of all of the operators having
   * been called in the order they were passed in.
   * @example
   * import { map, filter, scan } from 'rxjs/operators';
   * Rx.Observable.interval(1000)
   *   .pipe(
   *     filter(x => x % 2 === 0),
   *     map(x => x + x),
   *     scan((acc, x) => acc + x)
   *   )
   *   .subscribe(x => console.log(x))

In brief:

Pipe: Used to stitch together functional operators into a chain. Before we could just do observable.filter().map().scan(), but since every RxJS operator is a standalone function rather than an Observable's method, we need pipe() to make a chain of those operators (see example above).

Tap: Can perform side effects with observed data but does not modify the stream in any way. Formerly called do(). You can think of it as if observable was an array over time, then tap() would be an equivalent to Array.forEach().

How to load external webpage in WebView

You need to add WebView client

mWebView.setWebViewClient(new WebViewClient() {

   public void onPageFinished(WebView view, String url) {
        // do your stuff here

also you can use onPageFinished to do task after webview done loading web page

How do you find all subclasses of a given class in Java?

I needed to do this as a test case, to see if new classes had been added to the code. This is what I did

final static File rootFolder = new File(SuperClass.class.getProtectionDomain().getCodeSource().getLocation().getPath());
private static ArrayList<String> files = new ArrayList<String>();

@Test(timeout = 1000)
public void testNumberOfSubclasses(){
    ArrayList<String> listSubclasses = new ArrayList<>(files);
    listSubclasses.removeIf(s -> !s.contains("Superclass.class"));
    for(String subclass : listSubclasses){
    assertTrue("You did not create a new subclass!", listSubclasses.size() >1);     

public static void listFilesForFolder(final File folder) {
    for (final File fileEntry : folder.listFiles()) {
        if (fileEntry.isDirectory()) {
        } else {

How to get values from selected row in DataGrid for Windows Form Application?


Assuming i understand your question.

You can get the selected row using the DataGridView.SelectedRows Collection. If your DataGridView allows only one selected, have a look at my sample.

DataGridView.SelectedRows Gets the collection of rows selected by the user.


if (dataGridView1.SelectedRows.Count != 0)
    DataGridViewRow row = this.dataGridView1.SelectedRows[0];

More Information

Local and global temporary tables in SQL Server

I find this explanation quite clear (it's pure copy from Technet):

There are two types of temporary tables: local and global. Local temporary tables are visible only to their creators during the same connection to an instance of SQL Server as when the tables were first created or referenced. Local temporary tables are deleted after the user disconnects from the instance of SQL Server. Global temporary tables are visible to any user and any connection after they are created, and are deleted when all users that are referencing the table disconnect from the instance of SQL Server.

Remove a parameter to the URL with JavaScript

function removeParam(parameter)
  var url=document.location.href;
  var urlparts= url.split('?');

 if (urlparts.length>=2)
  var urlBase=urlparts.shift(); 
  var queryString=urlparts.join("?"); 

  var prefix = encodeURIComponent(parameter)+'=';
  var pars = queryString.split(/[&;]/g);
  for (var i= pars.length; i-->0;)               
      if (pars[i].lastIndexOf(prefix, 0)!==-1)   
          pars.splice(i, 1);
  url = urlBase+'?'+pars.join('&');
  window.history.pushState('',document.title,url); // added this line to push the new url directly to url bar .

return url;

This will resolve your problem

Get height and width of a layout programmatically

As CapDroid say, you are trying to get the size before the view drawn, another possible solution could be to do a Post with a runnable on the View: Runnable() {
        public void run() {
            int width = mView.getWidth();
            int height = mView.getHeight();

subquery in FROM must have an alias

In the case of nested tables, some DBMS require to use an alias like MySQL and Oracle but others do not have such a strict requirement, but still allow to add them to substitute the result of the inner query.

CSS3 Spin Animation

You haven't specified any keyframes. I made it work here.

div {
    margin: 20px;
    width: 100px; 
    height: 100px;    
    background: #f00;
    -webkit-animation: spin 4s infinite linear;

@-webkit-keyframes spin {
    0%  {-webkit-transform: rotate(0deg);}
    100% {-webkit-transform: rotate(360deg);}   

You can actually do lots of really cool stuff with this. Here is one I made earlier.


N.B. You can skip having to write out all the prefixes if you use -prefix-free.

PHP Header redirect not working

Don't include header.php. You should not output HTML when you are going to redirect.

Make a new file, eg. "pre.php". Put this in it:


Then in header.php, include that, in stead of including the two other files. In form.php, include pre.php in stead of header.php.

Flutter - Layout a Grid

There are few named constructors in GridView for different scenarios,


  1. GridView
  2. GridView.builder
  3. GridView.count
  4. GridView.custom
  5. GridView.extent

Below is a example of GridView constructor:

import 'package:flutter/material.dart';

void main() => runApp(
    home: ExampleGrid(),

class ExampleGrid extends StatelessWidget {
  List<String> images = [
  Widget build(BuildContext context) {
    return Scaffold(
      body: GridView(
        physics: BouncingScrollPhysics(), // if you want IOS bouncing effect, otherwise remove this line
        gridDelegate: SliverGridDelegateWithFixedCrossAxisCount(crossAxisCount: 2),//change the number as you want
        children: {
          return Card(child:;

If you want your GridView items to be dynamic according to the content, you can few lines to do that but the simplest way to use StaggeredGridView package. I have provided an answer with example here.

Below is an example for a GridView.count:

import 'package:flutter/material.dart';

void main() => runApp(
        home: ExampleGrid(),

class ExampleGrid extends StatelessWidget {
  Widget build(BuildContext context) {
    return Scaffold(
      body: GridView.count(
        crossAxisCount: 4,
        children: List.generate(40, (index) {
          return Card(
          ); // api provide you different images for any number you are giving

Screenshot for above snippet:

Flutter gridview example by blasanka using card widget and robohash api

Example for a SliverGridView:

import 'package:flutter/material.dart';

void main() => runApp(
        home: ExampleGrid(),

class ExampleGrid extends StatelessWidget {
  Widget build(BuildContext context) {
    return Scaffold(
      body: CustomScrollView(
        primary: false,
        slivers: <Widget>[
            padding: const EdgeInsets.all(20.0),
            sliver: SliverGrid.count(
              crossAxisSpacing: 10.0,
              crossAxisCount: 2,
              children: List.generate(20, (index) {
                return Card(child:"$index"));

How to move the layout up when the soft keyboard is shown android

I solve this by adding code into manifest:

<activity android:name=".Login"

How do I rotate the Android emulator display?

You can use Numpad-9 and Numpad-7 to rotate on Windows and Ubuntu.

How to preventDefault on anchor tags?

Lot of answers seem to be overkill. FOR ME , this works

 <a ng-href="#" ng-click="$event.preventDefault();vm.questionContainer($index)">{{question.Verbiage}}</a>

Show week number with Javascript?

Some of the code I see in here fails with years like 2016, in which week 53 jumps to week 2.

Here is a revised and working version:

Date.prototype.getWeek = function() { 

  // Create a copy of this date object  
  var target  = new Date(this.valueOf());  

  // ISO week date weeks start on monday, so correct the day number  
  var dayNr   = (this.getDay() + 6) % 7;  

  // Set the target to the thursday of this week so the  
  // target date is in the right year  
  target.setDate(target.getDate() - dayNr + 3);  

  // ISO 8601 states that week 1 is the week with january 4th in it  
  var jan4    = new Date(target.getFullYear(), 0, 4);  

  // Number of days between target date and january 4th  
  var dayDiff = (target - jan4) / 86400000;    

  if(new Date(target.getFullYear(), 0, 1).getDay() < 5) {
    // Calculate week number: Week 1 (january 4th) plus the    
    // number of weeks between target date and january 4th    
    return 1 + Math.ceil(dayDiff / 7);    
  else {  // jan 4th is on the next week (so next week is week 1)
    return Math.ceil(dayDiff / 7); 

How to copy a char array in C?

Well, techincally you can…

typedef struct { char xx[18]; } arr_wrap;

char array1[18] = "abcdefg";
char array2[18];

*((arr_wrap *) array2) = *((arr_wrap *) array1);

printf("%s\n", array2);     /* "abcdefg" */

but it will not look very beautiful.

…Unless you use the C preprocessor…

    { struct _tmparrwrap_ { char xx[ARRSIZE]; }; *((struct _tmparrwrap_ *) DESTARR) = *((struct _tmparrwrap_ *) SRCARR); }

You can then do:

char array1[18] = "abcdefg";
char array2[18];

CC_MEMCPY(array2, array1, sizeof(array1));

printf("%s\n", array2);     /* "abcdefg" */

And it will work with any data type, not just char:

int numbers1[3] = { 1, 2, 3 };
int numbers2[3];

CC_MEMCPY(numbers2, numbers1, sizeof(numbers1));

printf("%d - %d - %d\n", numbers2[0], numbers2[1], numbers2[2]);     /* "abcdefg" */

(Yes, the code above is granted to work always and it's portable)

How do I parse a string to a float or int?

The question seems a little bit old. But let me suggest a function, parseStr, which makes something similar, that is, returns integer or float and if a given ASCII string cannot be converted to none of them it returns it untouched. The code of course might be adjusted to do only what you want:

   >>> import string
   >>> parseStr = lambda x: x.isalpha() and x or x.isdigit() and \
   ...                      int(x) or x.isalnum() and x or \
   ...                      len(set(string.punctuation).intersection(x)) == 1 and \
   ...                      x.count('.') == 1 and float(x) or x
   >>> parseStr('123')
   >>> parseStr('123.3')
   >>> parseStr('3HC1')
   >>> parseStr('12.e5')
   >>> parseStr('12$5')
   >>> parseStr('12.2.2')

How to get evaluated attributes inside a custom directive

The other answers here are very much correct, and valuable. But sometimes you just want simple: to get a plain old parsed value at directive instantiation, without needing updates, and without messing with isolate scope. For instance, it can be handy to provide a declarative payload into your directive as an array or hash-object in the form:

my-directive-name="['string1', 'string2']"

In that case, you can cut to the chase and just use a nice basic angular.$eval(attr.attrName).

element.val("value = "+angular.$eval(attr.value));

Working Fiddle.

How can I set the current working directory to the directory of the script in Bash?

cd "$(dirname "${BASH_SOURCE[0]}")"

It's easy. It works.

How to parse JSON using Node.js?

you can require .json files.

var parsedJSON = require('./file-name');

For example if you have a config.json file in the same directory as your source code file you would use:

var config = require('./config.json');

or (file extension can be omitted):

var config = require('./config');

note that require is synchronous and only reads the file once, following calls return the result from cache

Also note You should only use this for local files under your absolute control, as it potentially executes any code within the file.

Build the full path filename in Python

If you are fortunate enough to be running Python 3.4+, you can use pathlib:

>>> from pathlib import Path
>>> dirname = '/home/reports'
>>> filename = 'daily'
>>> suffix = '.pdf'
>>> Path(dirname, filename).with_suffix(suffix)

How do I interpret precision and scale of a number in a database?

Precision, Scale, and Length in the SQL Server 2000 documentation reads:

Precision is the number of digits in a number. Scale is the number of digits to the right of the decimal point in a number. For example, the number 123.45 has a precision of 5 and a scale of 2.

How to change font of UIButton with Swift

If you need to change only size (Swift 4.0):

button.titleLabel?.font = button.titleLabel?.font.withSize(12)

JavaScript: IIF like statement

I typed this in my URL bar:

javascript:{ var col = 'screwdriver'; var x = '<option value="' + col + '"' + ((col == 'screwdriver') ? ' selected' : '') + '>Very roomy</option>'; alert(x); }

CSS overflow-x: visible; and overflow-y: hidden; causing scrollbar issue

I originally found a CSS way to bypass this when using the Cycle jQuery plugin. Cycle uses JavaScript to set my slide to overflow: hidden, so when setting my pictures to width: 100% the pictures would look vertically cut, and so I forced them to be visible with !important and to avoid showing the slide animation out of the box I set overflow: hidden to the container div of the slide. Hope it works for you.

UPDATE - New Solution:

Original problem -> (Even if I use overflow-y: visible it becomes "auto" and actually "scroll".)

#content {
    height: 100px;
    width: 200px;
    overflow-x: hidden;
    overflow-y: visible;

The new solution -> (I found a workaround using a wrapper div to apply overflow-x and overflow-y to different DOM elements as James Khoury advised on the problem of combining visible and hidden to a single DOM element.)

#wrapper {
    height: 100px;
    overflow-y: visible;
#content {
    width: 200px;
    overflow-x: hidden;

How can you run a command in bash over and over until success?

You need to test $? instead, which is the exit status of the previous command. passwd exits with 0 if everything worked ok, and non-zero if the passwd change failed (wrong password, password mismatch, etc...)

while [ $? -ne 0 ]; do

With your backtick version, you're comparing passwd's output, which would be stuff like Enter password and confirm password and the like.

PHP $_POST not working?

I had something similar this evening which was driving me batty. Submitting a form was giving me the values in $_REQUEST but not in $_POST.

Eventually I noticed that there were actually two requests going through on the network tab in firebug; first a POST with a 301 response, then a GET with a 200 response.

Hunting about the interwebs it sounded like most people thought this was to do with mod_rewrite causing the POST request to redirect and thus change to a GET.

In my case it wasn't mod_rewrite to blame, it was something far simpler... my URL for the POST also contained a GET query string which was starting without a trailing slash on the URL. It was this causing apache to redirect.

Spot the difference...


The bottom one doesn't cause a redirect and gives me $_POST!

How get permission for camera in android.(Specifically Marshmallow)

I try to add following code:

private static final int MY_CAMERA_REQUEST_CODE = 100;

@RequiresApi(api = Build.VERSION_CODES.M)

if (checkSelfPermission(Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED) {
        requestPermissions(new String[]{Manifest.permission.CAMERA}, MY_CAMERA_REQUEST_CODE);

On onCreate Function and this following code:

public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
    super.onRequestPermissionsResult(requestCode, permissions, grantResults);
    if (requestCode == MY_CAMERA_REQUEST_CODE) {
        if (grantResults[0] == PackageManager.PERMISSION_GRANTED) {
            Toast.makeText(this, "camera permission granted", Toast.LENGTH_LONG).show();
        } else {
            Toast.makeText(this, "camera permission denied", Toast.LENGTH_LONG).show();

And this worked for me :)

How do you rotate a two dimensional array?

Great answers but for those who are looking for a DRY JavaScript code for this - both +90 Degrees and -90 Degrees:

          // Input: 1 2 3_x000D_
          //        4 5 6_x000D_
          //        7 8 9_x000D_
          // Transpose: _x000D_
          //       1 4 7_x000D_
          //       2 5 8_x000D_
          //       3 6 9_x000D_
          // Output: _x000D_
          // +90 Degree:_x000D_
          //       7 4 1_x000D_
          //       8 5 2_x000D_
          //       9 6 3_x000D_
          // -90 Degree:_x000D_
          //      3 6 9_x000D_
          //      2 5 8_x000D_
          //      1 4 7_x000D_
          // Rotate +90_x000D_
         function rotate90(matrix) {_x000D_
           matrix = transpose(matrix);_x000D_
           return matrix;_x000D_
          // Rotate -90_x000D_
         function counterRotate90(matrix) {_x000D_
           var result = createEmptyMatrix(matrix.length);_x000D_
           matrix = transpose(matrix);_x000D_
           var counter = 0;_x000D_
           for (var i = matrix.length - 1; i >= 0; i--) {_x000D_
             result[counter] = matrix[i];_x000D_
           return result;_x000D_
          // Create empty matrix_x000D_
         function createEmptyMatrix(len) {_x000D_
           var result = new Array();_x000D_
           for (var i = 0; i < len; i++) {_x000D_
           return result;_x000D_
          // Transpose the matrix_x000D_
         function transpose(matrix) {_x000D_
           // make empty array_x000D_
           var len = matrix.length;_x000D_
           var result = createEmptyMatrix(len);_x000D_
           for (var i = 0; i < matrix.length; i++) {_x000D_
             for (var j = 0; j < matrix[i].length; j++) {_x000D_
               var temp = matrix[i][j];_x000D_
               result[j][i] = temp;_x000D_
           return result;_x000D_
          // Test Cases_x000D_
         var array1 = [_x000D_
           [1, 2],_x000D_
           [3, 4]_x000D_
         var array2 = [_x000D_
           [1, 2, 3],_x000D_
           [4, 5, 6],_x000D_
           [7, 8, 9]_x000D_
         var array3 = [_x000D_
           [1, 2, 3, 4],_x000D_
           [5, 6, 7, 8],_x000D_
           [9, 10, 11, 12],_x000D_
           [13, 14, 15, 16]_x000D_
          // +90 degress Rotation Tests_x000D_
         var test1 = rotate90(array1);_x000D_
         var test2 = rotate90(array2);_x000D_
         var test3 = rotate90(array3);_x000D_
          // -90 degress Rotation Tests_x000D_
         var test1 = counterRotate90(array1);_x000D_
         var test2 = counterRotate90(array2);_x000D_
         var test3 = counterRotate90(array3);_x000D_

Remove all files except some from a directory

Since nobody mentioned it:

  • copy the files you don't want to delete in a safe place
  • delete all the files
  • move the copied files back in place

TypeError: unsupported operand type(s) for /: 'str' and 'str'

There is another error with the forwars=d slash.

if we get this : def get_x(r): return path/'train'/r['fname']
is the same as def get_x(r): return path + 'train' + r['fname']

How to do a background for a label will be without color?

This uses Graphics.CopyFromScreen so the control needs to be added when it's visable on screen.

public partial class TransparentLabelControl : Label
    public TransparentLabelControl()
        this.AutoSize = true;
        this.Visible = false;

        this.ImageAlign = ContentAlignment.TopLeft;
        this.Visible = true;

        this.Resize += TransparentLabelControl_Resize;
        this.LocationChanged += TransparentLabelControl_LocationChanged;
        this.TextChanged += TransparentLabelControl_TextChanged;
        this.ParentChanged += TransparentLabelControl_ParentChanged;

    #region Events
    private void TransparentLabelControl_ParentChanged(object sender, EventArgs e)
        if (this.Parent != null)
            this.Parent.ControlAdded += Parent_ControlAdded;
            this.Parent.ControlRemoved += Parent_ControlRemoved;

    private void Parent_ControlRemoved(object sender, ControlEventArgs e)

    private void Parent_ControlAdded(object sender, ControlEventArgs e)
        if (this.Bounds.IntersectsWith(e.Control.Bounds))

    private void TransparentLabelControl_TextChanged(object sender, EventArgs e)

    private void TransparentLabelControl_LocationChanged(object sender, EventArgs e)


    private void TransparentLabelControl_Resize(object sender, EventArgs e)

    public void SetTransparent()
        if (this.Parent!= null)
            this.Visible = false;
            this.Image = this.takeComponentScreenShot(this.Parent);
            this.Visible = true;                

    private  Bitmap takeComponentScreenShot(Control control)
        Rectangle rect = control.RectangleToScreen(this.Bounds);
        if (rect.Width == 0 || rect.Height == 0)
            return null;
        Bitmap bmp = new Bitmap(rect.Width, rect.Height, PixelFormat.Format32bppArgb);
        Graphics g = Graphics.FromImage(bmp);

        g.CopyFromScreen(rect.Left, rect.Top, 0, 0, bmp.Size, CopyPixelOperation.SourceCopy);

        return bmp;


How do I get a consistent byte representation of strings in C# without manually specifying an encoding?

If you are using .NET Core or System.Memory for .NET Framework, there is a very efficient marshaling mechanism available via Span<T> and Memory<T> that can effectively reinterpret string memory as a span of bytes. Once you have a span of bytes you are free to marshal back to another type, or copy the span to an array for serialization.

To summarize what others have said:

  • Storing a representation of this kind of serialization is sensitive to system endianness, compiler optimizations, and changes to the internal representation of strings in the executing .NET Runtime.
    • Avoid long-term storage
    • Avoid deserializing or interpreting the string in other environments
      • This includes other machines, processor architectures, .NET runtimes, containers, etc.
      • This includes comparisons, formatting, encryption, string manipulation, localization, character transforms, etc.
    • Avoid making assumptions about the character encoding
      • The default encoding tends to be UTF-16LE in practice, but the compiler / runtime can choose any internal representation


public static class MarshalExtensions
   public static ReadOnlySpan<byte> AsBytes(this string value) => MemoryMarshal.AsBytes(value.AsSpan());
   public static string AsString(this ReadOnlySpan<byte> value) => new string(MemoryMarshal.Cast<byte, char>(value));


static void Main(string[] args)
    string str1 = "??,??";
    ReadOnlySpan<byte> span = str1.AsBytes();
    string str2 = span.AsString();

    byte[] bytes = span.ToArray();

    Debug.Assert(bytes.Length > 0);
    Debug.Assert(str1 == str2);

Furthur Insight

In C++ this is roughly equivalent to reinterpret_cast, and C this is roughly equivalent to a cast to the system's word type (char).

In recent versions of the .NET Core Runtime (CoreCLR), operations on spans effectively invoke compiler intrinsics and various optimizations that can sometimes eliminate bounds checking, leading to exceptional performance while preserving memory safety, assuming that your memory was allocated by the CLR and the spans are not derived from pointers from an unmanaged memory allocator.


This uses a mechanism supported by the CLR that returns ReadOnlySpan<char> from a string; Additionally, this span does not necessarily encompass the complete internal string layout. ReadOnlySpan<T> implies that you must create a copy if you need to perform mutation, as strings are immutable.

The remote host closed the connection. The error code is 0x800704CD

One can reproduce the error with the code below:

public ActionResult ClosingTheConnectionAction(){
      //we need to set buffer to false to
      //make sure data is written in chunks
      Response.Buffer = false;  
      var someText = "Some text here to make things happen ;-)";
      var content = GetBytes( someText );

      for(var i=0; i < 100; i++)
         Response.OutputStream.Write(content, 0, content.Length);

      return View();
   catch(HttpException hex)
      if (hex.Message.StartsWith("The remote host closed the connection. The error code is 0x800704CD."))
                //react on remote host closed the connection exception.
                var msg = hex.Message;
   catch(Exception somethingElseHappened)
      //handle it with some other code

   return View();

Now run the website in debug mode. Put a breakpoint in the loop that writes to the output stream. Go to that action method and after the first iteration passed close the tab of the browser. Hit F10 to continue the loop. After it hit the next iteration you will see the exception. Enjoy your exception :-)

Get current AUTO_INCREMENT value for any table

mysqli executable sample code:

    $db = new mysqli("localhost", "user", "password", "YourDatabaseName");
    if ($db->connect_errno) die ($db->connect_error);

    $table=$db->prepare("SHOW TABLE STATUS FROM YourDatabaseName");
    $sonuc = $table->get_result();
    while ($satir=$sonuc->fetch_assoc()){
        if ($satir["Name"]== "YourTableName"){
    echo $LastAutoIncrement;

How can I access global variable inside class in Python

By declaring it global inside the function that accesses it:

g_c = 0

class TestClass():
    def run(self):
        global g_c
        for i in range(10):
            g_c = 1

The Python documentation says this, about the global statement:

The global statement is a declaration which holds for the entire current code block.

Displaying all table names in php from MySQL database

you need to assign the mysql_query to a variable (eg $result), then display this variable as you would a normal result from the database.

How do I change the font size of a UILabel in Swift?

label.font = UIFont.systemFontOfSize(20)

Dynamic constant assignment

Because constants in Ruby aren't meant to be changed, Ruby discourages you from assigning to them in parts of code which might get executed more than once, such as inside methods.

Under normal circumstances, you should define the constant inside the class itself:

class MyClass
  MY_CONSTANT = "foo"

MyClass::MY_CONSTANT #=> "foo"

If for some reason though you really do need to define a constant inside a method (perhaps for some type of metaprogramming), you can use const_set:

class MyClass
  def my_method
    self.class.const_set(:MY_CONSTANT, "foo")

#=> NameError: uninitialized constant MyClass::MY_CONSTANT
MyClass::MY_CONSTANT #=> "foo"

Again though, const_set isn't something you should really have to resort to under normal circumstances. If you're not sure whether you really want to be assigning to constants this way, you may want to consider one of the following alternatives:

Class variables

Class variables behave like constants in many ways. They are properties on a class, and they are accessible in subclasses of the class they are defined on.

The difference is that class variables are meant to be modifiable, and can therefore be assigned to inside methods with no issue.

class MyClass
  def self.my_class_variable
  def my_method
    @@my_class_variable = "foo"
class SubClass < MyClass

#=> NameError: uninitialized class variable @@my_class_variable in MyClass
#=> NameError: uninitialized class variable @@my_class_variable in MyClass
MyClass.my_class_variable #=> "foo"
SubClass.my_class_variable #=> "foo"

Class attributes

Class attributes are a sort of "instance variable on a class". They behave a bit like class variables, except that their values are not shared with subclasses.

class MyClass
  class << self
    attr_accessor :my_class_attribute
  def my_method
    self.class.my_class_attribute = "blah"
class SubClass < MyClass

MyClass.my_class_attribute #=> nil
SubClass.my_class_attribute #=> nil
MyClass.my_class_attribute #=> "blah"
SubClass.my_class_attribute #=> nil
SubClass.my_class_attribute #=> "blah"

Instance variables

And just for completeness I should probably mention: if you need to assign a value which can only be determined after your class has been instantiated, there's a good chance you might actually be looking for a plain old instance variable.

class MyClass
  attr_accessor :instance_variable
  def my_method
    @instance_variable = "blah"

my_object =
my_object.instance_variable #=> nil
my_object.instance_variable #=> "blah" #=> nil

How do I remove lines between ListViews on Android?

You can put below property in listview tag


(or) programmatically listview.Divider(null); here listview is ListView reference.

Difference between EXISTS and IN in SQL?

I found that using EXISTS keyword is often really slow (that is very true in Microsoft Access). I instead use the join operator in this manner : should-i-use-the-keyword-exists-in-sql

Routing with multiple Get methods in ASP.NET Web API

After reading lots of answers finally I figured out.

First, I added 3 different routes into WebApiConfig.cs

public static void Register(HttpConfiguration config)
    // Web API configuration and services

    // Web API routes

        name: "ApiById",
        routeTemplate: "api/{controller}/{id}",
        defaults: new { id = RouteParameter.Optional },
        constraints: new { id = @"^[0-9]+$" }

        name: "ApiByName",
        routeTemplate: "api/{controller}/{action}/{name}",
        defaults: null,
        constraints: new { name = @"^[a-z]+$" }

        name: "ApiByAction",
        routeTemplate: "api/{controller}/{action}",
        defaults: new { action = "Get" }

Then, removed ActionName, Route, etc.. from the controller functions. So basically this is my controller;

// GET: api/Countries/5
public async Task<IHttpActionResult> GetCountries(int id)
    Countries countries = await db.Countries.FindAsync(id);
    if (countries == null)
        return NotFound();

    return Ok(countries);

// GET: api/Countries/tur
public async Task<IHttpActionResult> GetCountriesByName(string name)
    var countries = await db.Countries

    if (countries == null)
        return NotFound();

    return Ok(countries);

Now I am able to run with following url samples(with name and with id);



Disable Transaction Log

What's your problem with Tx logs? They grow? Then just set truncate on checkpoint option.

From Microsoft documentation:

In SQL Server 2000 or in SQL Server 2005, the "Simple" recovery model is equivalent to "truncate log on checkpoint" in earlier versions of SQL Server. If the transaction log is truncated every time a checkpoint is performed on the server, this prevents you from using the log for database recovery. You can only use full database backups to restore your data. Backups of the transaction log are disabled when the "Simple" recovery model is used.

What is the 'instanceof' operator used for in Java?

This operator allows you to determine the type of an object. It returns a boolean value.

For example

package test;

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

public class instanceoftest
    public static void main(String args[])
        Map m=new HashMap();
        System.out.println("Returns a boolean value "+(m instanceof Map));
        System.out.println("Returns a boolean value "+(m instanceof HashMap));
        System.out.println("Returns a boolean value "+(m instanceof Object));
        System.out.println("Returns a boolean value "+(m instanceof Date));

the output is:

Returns a boolean value true
Returns a boolean value true
Returns a boolean value true
Returns a boolean value false

AddTransient, AddScoped and AddSingleton Services Differences

Transient, scoped and singleton define object creation process in ASP.NET MVC core DI when multiple objects of the same type have to be injected. In case you are new to dependency injection you can see this DI IoC video.

You can see the below controller code in which I have requested two instances of "IDal" in the constructor. Transient, Scoped and Singleton define if the same instance will be injected in "_dal" and "_dal1" or different.

public class CustomerController : Controller
    IDal dal = null;

    public CustomerController(IDal _dal,
                              IDal _dal1)
        dal = _dal;
        // DI of MVC core
        // inversion of control

Transient: In transient, new object instances will be injected in a single request and response. Below is a snapshot image where I displayed GUID values.

Enter image description here

Scoped: In scoped, the same object instance will be injected in a single request and response.

Enter image description here

Singleton: In singleton, the same object will be injected across all requests and responses. In this case one global instance of the object will be created.

Below is a simple diagram which explains the above fundamental visually.

MVC DI image

The above image was drawn by the SBSS team when I was taking ASP.NET MVC training in Mumbai. A big thanks goes to the SBSS team for creating the above image.

MS Access - execute a saved query by name in VBA

You should investigate why VBA can't find queryname.

I have a saved query named qryAddLoginfoRow. It inserts a row with the current time into my loginfo table. That query runs successfully when called by name by CurrentDb.Execute.

CurrentDb.Execute "qryAddLoginfoRow"

My guess is that either queryname is a variable holding the name of a query which doesn't exist in the current database's QueryDefs collection, or queryname is the literal name of an existing query but you didn't enclose it in quotes.

Edit: You need to find a way to accept that queryname does not exist in the current db's QueryDefs collection. Add these 2 lines to your VBA code just before the CurrentDb.Execute line.

Debug.Print "queryname = '" & queryname & "'"
Debug.Print CurrentDb.QueryDefs(queryname).Name

The second of those 2 lines will trigger run-time error 3265, "Item not found in this collection." Then go to the Immediate window to verify the name of the query you're asking CurrentDb to Execute.

jQuery checkbox onChange

There is no need to use :checkbox, also replace #activelist with #inactivelist:

$('#inactivelist').change(function () {

What is the best way to ensure only one instance of a Bash script is running?

first test example

[[ $(lsof -t $0| wc -l) > 1 ]] && echo "At least one of $0 is running"

second test example

runpid=$(lsof -t $currsh| paste -s -d " ")
if [[ $runpid == $currpid ]]
  sleep 11111111111111111
  echo -e "\nPID($runpid)($currpid) ::: At least one of \"$currsh\" is running !!!\n"
  exit 1


"lsof -t" to list all pids of current running scripts named "$0".

Command "lsof" will do two advantages.

  1. Ignore pids which is editing by editor such as vim, because vim edit its mapping file such as ".file.swp".
  2. Ignore pids forked by current running shell scripts, which most "grep" derivative command can't achieve it. Use "pstree -pH pidnum" command to see details about current process forking status.

HTTP post XML data in C#

AlliterativeAlice's example helped me tremendously. In my case, though, the server I was talking to didn't like having single quotes around utf-8 in the content type. It failed with a generic "Server Error" and it took hours to figure out what it didn't like:

request.ContentType = "text/xml; encoding=utf-8";

Combining paste() and expression() functions in plot labels

EDIT: added a new example for ggplot2 at the end

See ?plotmath for the different mathematical operations in R

You should be able to use expression without paste. If you use the tilda (~) symbol within the expression function it will assume there is a space between the characters, or you could use the * symbol and it won't put a space between the arguments

Sometimes you will need to change the margins in you're putting superscripts on the y-axis.

par(mar=c(5, 4.3, 4, 2) + 0.1)
plot(1:10, xlab = expression(xLab ~ x^2 ~ m^-2),
     ylab = expression(yLab ~ y^2 ~ m^-2),
     main="Plot 1")

enter image description here

plot(1:10, xlab = expression(xLab * x^2 * m^-2),
     ylab = expression(yLab * y^2 * m^-2),
     main="Plot 2")

enter image description here

plot(1:10, xlab = expression(xLab ~ x^2 * m^-2),
     ylab = expression(yLab ~ y^2 * m^-2),
     main="Plot 3")

enter image description here

Hopefully you can see the differences between plots 1, 2 and 3 with the different uses of the ~ and * symbols. An extra note, you can use other symbols such as plotting the degree symbol for temperatures for or mu, phi. If you want to add a subscript use the square brackets.

plot(1:10, xlab = expression('Your x label' ~ mu[3] * phi),
     ylab = expression("Temperature (" * degree * C *")"))

enter image description here

Here is a ggplot example using expression with a nonsense example


Or if you have the pacman library installed you can use p_load to automatically download and load and attach add-on packages

# require(pacman)
# p_load(ggplot2)

data = data.frame(x = 1:10, y = 1:10)

ggplot(data, aes(x,y)) + geom_point() + 
  xlab(expression(bar(yourUnits) ~ g ~ m^-2 ~ OR ~ integral(f(x)*dx, a,b))) + 
  ylab(expression("Biomass (g per" ~ m^3 *")")) + theme_bw()

enter image description here

How can I search for a commit message on GitHub?

If you have a local version of the repository, you might want to try this crude shell script I wrote to open the GitHub pages for all commits matching your search term in new tabs in your default browser:

for sha1 in $(git rev-list HEAD -i --grep="$1"); do
    python -mwebbrowser$sha1 >/dev/null 2>/dev/null

Just replace with the actual GitHub URL of your repository, save the script somewhere (e.g. as, make it executable (chmod +x and then add the following alias to your ~/.bashrc file:

alias githubsearch='/path/to/'

Then, from anywhere in your Git repository, just do this at the terminal:

githubsearch "what you want to search for"

and any commits that match your (case insensitive) search term will have their corresponding GitHub pages opened in your browser. (Be warned that if your search term appears in hundreds of commits, this may well crash your browser and eat your PC's CPU for a while.)

Add a pipe separator after items in an unordered list unless that item is the last on a line

I came across a solution today that does not appear to be here already and which seems to work quite well so far. The accepted answer does not work as-is on IE10 but this one does. credit to the author of course!

.pipe-separated-list-container {_x000D_
  overflow-x: hidden;_x000D_
.pipe-separated-list-container ul {_x000D_
  list-style-type: none;_x000D_
  position: relative;_x000D_
  left: -1px;_x000D_
  padding: 0;_x000D_
.pipe-separated-list-container ul li {_x000D_
  display: inline-block;_x000D_
  line-height: 1;_x000D_
  padding: 0 1em;_x000D_
  margin-bottom: 1em;_x000D_
  border-left: 1px solid;_x000D_
<div class="pipe-separated-list-container">_x000D_
    <li>Twenty One</li>_x000D_
    <li>Twenty Two</li>_x000D_
    <li>Twenty Three</li>_x000D_
    <li>Twenty Four</li>_x000D_
    <li>Twenty Five</li>_x000D_
    <li>Twenty Six</li>_x000D_
    <li>Twenty Seven</li>_x000D_
    <li>Twenty Eight</li>_x000D_
    <li>Twenty Nine</li>_x000D_

Determining if a number is prime

      cout<<"Number is prime:"<<endl;

The code is incredibly false. 33 divided by 2 is 16 with reminder of 1 but it's not a prime number...

Add CSS or JavaScript files to layout head from views or partial views

I tried to solve this issue.

My answer is here.

"DynamicHeader" -,

For example, _Layout.cshtml is:


And, you can register .js and .css files to "DynamicHeader" anywhere you want.

For example, the code block in AnotherPartial.cshtml is:


Result HTML output for this sample is:

  <link href="/myapp/Content/themes/base/AnotherPartial.css" .../>
  <script src="/myapp/some/myscript.js" ...></script>

IE9 JavaScript error: SCRIPT5007: Unable to get value of the property 'ui': object is null or undefined

I have written code that sniffs IE4 or greater and is currently functioning perfectly in sites for my company's clients, as well as my own personal sites.

Include the following enumerated constant and function variables into a javascript include file on your page...

var BrowserTypes = {
    Unknown: 0,
    FireFox: 1,
    Chrome: 2,
    Safari: 3,
    IE: 4,
    IE7: 5,
    IE8: 6,
    IE9: 7,
    IE10: 8,
    IE11: 8,
    IE12: 8

var Browser = function () {
    try {
        var type;
        var version;
        var sVersion;

        switch (navigator.appName.toLowerCase()) {
            case "microsoft internet explorer":
                type = BrowserTypes.IE;
                sVersion = navigator.appVersion.substring(navigator.appVersion.indexOf('MSIE') + 5, navigator.appVersion.length);
                version = parseFloat(sVersion.split(";")[0]);
                switch (parseInt(version)) {
                    case 7:
                        type = BrowserTypes.IE7;
                    case 8:
                        type = BrowserTypes.IE8;
                    case 9:
                        type = BrowserTypes.IE9;
                    case 10:
                        type = BrowserTypes.IE10;
                    case 11:
                        type = BrowserTypes.IE11;
                    case 12:
                        type = BrowserTypes.IE12;
            case "netscape":
                if (navigator.userAgent.toLowerCase().indexOf("chrome") > -1) { type = BrowserTypes.Chrome; }
                else { if (navigator.userAgent.toLowerCase().indexOf("firefox") > -1) { type = BrowserTypes.FireFox } };
                type = BrowserTypes.Unknown;

        return type;
    } catch (ex) {

Then all you have to do is use any conditional functionality such as...

ie. value = (Browser() >= BrowserTypes.IE) ? node.text : node.textContent;

or WindowWidth = (((Browser() >= BrowserTypes.IE9) || (Browser() < BrowserTypes.IE)) ? window.innerWidth : document.documentElement.clientWidth);

or sJSON = (Browser() >= BrowserTypes.IE) ? xmlElement.text : xmlElement.textContent;

Get the idea? Hope this helps.

Oh, you might want to keep it in mind to QA the Browser() function after IE10 is released, just to verify they didn't change the rules.

Angular 5, HTML, boolean on checkbox is checked

When you have a copy of an object the [checked] attribute might not work, in that case, you can use (change) in this way:

        <input type="checkbox" [checked]="item.selected" (change)="item.selected = !item.selected">

What is the difference between Hibernate and Spring Data JPA

There are 3 different things we are using here :

  1. JPA : Java persistence api which provide specification for persisting, reading, managing data from your java object to relations in database.
  2. Hibernate: There are various provider which implement jpa. Hibernate is one of them. So we have other provider as well. But if using jpa with spring it allows you to switch to different providers in future.
  3. Spring Data JPA : This is another layer on top of jpa which spring provide to make your life easy.

So lets understand how spring data jpa and spring + hibernate works-

Spring Data JPA:

Let's say you are using spring + hibernate for your application. Now you need to have dao interface and implementation where you will be writing crud operation using SessionFactory of hibernate. Let say you are writing dao class for Employee class, tomorrow in your application you might need to write similiar crud operation for any other entity. So there is lot of boilerplate code we can see here.

Now Spring data jpa allow us to define dao interfaces by extending its repositories(crudrepository, jparepository) so it provide you dao implementation at runtime. You don't need to write dao implementation anymore.Thats how spring data jpa makes your life easy.

Proper usage of Java -D command-line parameters

You're giving parameters to your program instead to Java. Use

java -Dtest="true" -jar myApplication.jar 


Consider using


to avoid the NPE. But do not use "Yoda conditions" always without thinking, sometimes throwing the NPE is the right behavior and sometimes something like

System.getProperty("test") == null || System.getProperty("test").equalsIgnoreCase("true")

is right (providing default true). A shorter possibility is


but not using double negation doesn't make it less hard to misunderstand.

Explanation on Integer.MAX_VALUE and Integer.MIN_VALUE to find min and max value in an array

but as for this method, I don't understand the purpose of Integer.MAX_VALUE and Integer.MIN_VALUE.

By starting out with smallest set to Integer.MAX_VALUE and largest set to Integer.MIN_VALUE, they don't have to worry later about the special case where smallest and largest don't have a value yet. If the data I'm looking through has a 10 as the first value, then numbers[i]<smallest will be true (because 10 is < Integer.MAX_VALUE) and we'll update smallest to be 10. Similarly, numbers[i]>largest will be true because 10 is > Integer.MIN_VALUE and we'll update largest. And so on.

Of course, when doing this, you must ensure that you have at least one value in the data you're looking at. Otherwise, you end up with apocryphal numbers in smallest and largest.

Note the point Onome Sotu makes in the comments:

...if the first item in the array is larger than the rest, then the largest item will always be Integer.MIN_VALUE because of the else-if statement.

Which is true; here's a simpler example demonstrating the problem (live copy):

public class Example
    public static void main(String[] args) throws Exception {
        int[] values = {5, 1, 2};
        int smallest = Integer.MAX_VALUE;
        int largest  = Integer.MIN_VALUE;
        for (int value : values) {
            if (value < smallest) {
                smallest = value;
            } else if (value > largest) {
                largest = value;
        System.out.println(smallest + ", " + largest); // 1, 2 -- WRONG

To fix it, either:

  1. Don't use else, or

  2. Start with smallest and largest equal to the first element, and then loop the remaining elements, keeping the else if.

Here's an example of that second one (live copy):

public class Example
    public static void main(String[] args) throws Exception {
        int[] values = {5, 1, 2};
        int smallest = values[0];
        int largest  = values[0];
        for (int n = 1; n < values.length; ++n) {
            int value = values[n];
            if (value < smallest) {
                smallest = value;
            } else if (value > largest) {
                largest = value;
        System.out.println(smallest + ", " + largest); // 1, 5

Cannot access a disposed object - How to fix?

Looking at the error stack trace, it seems your timer is still active. Try to cancel the timer upon closing the form (i.e. in the form's OnClose() method). This looks like the cleanest solution.

Declaring and using MySQL varchar variables

This works fine for me using MySQL 5.1.35:


DROP PROCEDURE IF EXISTS `example`.`test` $$
CREATE PROCEDURE `example`.`test` ()

  DECLARE FOO varchar(7);
  DECLARE oldFOO varchar(7);
  SET FOO = '138';
  SET oldFOO = CONCAT('0', FOO);

  update mypermits
     set person = FOO
   where person = oldFOO;

END $$



DROP TABLE IF EXISTS `example`.`mypermits`;
CREATE TABLE  `example`.`mypermits` (
  `person` varchar(7) NOT NULL

INSERT INTO mypermits VALUES ('0138');

CALL test()

How to read an external properties file in Maven

Using the suggested Maven properties plugin I was able to read in a file that I use to version my builds.


How to write PNG image to string with the PIL?

sth's solution didn't work for me
because in ...

Imaging/PIL/Image.pyc line 1423 -> raise KeyError(ext) # unknown extension

It was trying to detect the format from the extension in the filename , which doesn't exist in StringIO case

You can bypass the format detection by setting the format yourself in a parameter

import StringIO
output = StringIO.StringIO()
format = 'PNG' # or 'JPEG' or whatever you want, format)
contents = output.getvalue()

Android Left to Right slide animation

If you want to apply the animation on "activity" start. then write below code.

overridePendingTransition(R.anim.opening_anim, R.anim.closing_anim);

If you want to apply the animation on "dialog" then firstly add below code in styles.xml file

<style name="my_style”> 

Use this style as I defined below.

final Dialog dialog = new Dialog(activity);
dialog.getWindow().getAttributes().windowAnimations =;

If you want to apply the animation on "view" then write below code

txtMessage = (TextView) findViewById(;
// load the animation
Animation animFadein = AnimationUtils.loadAnimation(getApplicationContext(),R.anim.animation); 

// start the animation

Below, I have mentioned most of the animation .xml code.

appear - make it just appear.xml

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="">


make it slowly fades into view.xml

<?xml version="1.0" encoding="UTF-8"?>
<set xmlns:android="">
        android:repeatCount="0" />


fadeout - make it slowly fade out of view.xml

<?xml version="1.0" encoding="UTF-8"?>
<set xmlns:android="">
        android:repeatCount="0" />



<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="">
    <translate android:fromYDelta="-100%p" android:toYDelta="0" android:duration="400"/>



<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="">
    <translate android:fromYDelta="0" android:toYDelta="100%p" android:duration="400"/>



<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="">
    <translate android:fromXDelta="100%p" android:toXDelta="0" android:duration="300"/>
    <alpha android:fromAlpha="0.0" android:toAlpha="1.0" android:duration="300" />



<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="">
    <translate android:fromXDelta="0" android:toXDelta="-100%p" android:duration="300"/>
    <alpha android:fromAlpha="1.0" android:toAlpha="0.0" android:duration="300" />



<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="">
    <translate android:fromXDelta="-100%p" android:toXDelta="0" android:duration="300"/>
    <alpha android:fromAlpha="0.0" android:toAlpha="1.0" android:duration="300" />



<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="">
    <translate android:fromXDelta="0" android:toXDelta="100%p" android:duration="300"/>
    <alpha android:fromAlpha="1.0" android:toAlpha="0.0" android:duration="300" />



<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="">
    <translate android:fromYDelta="100%p" android:toYDelta="0" android:duration="300"/>
    <alpha android:fromAlpha="0.0" android:toAlpha="1.0" android:duration="300" />



<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="">
    <translate android:fromYDelta="0" android:toYDelta="-100%p" android:duration="300"/>
    <alpha android:fromAlpha="1.0" android:toAlpha="0.0" android:duration="300" />



<?xml version="1.0" encoding="utf-8"?>
    android:duration="0" android:fillAfter="true">



<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="">
    <scale android:fromYScale="0" android:toYScale="1.0"
        android:fromXScale="0" android:toXScale="1.0" 
        android:duration="500" android:pivotX="100%"
        android:pivotY="100%" />



<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="">
    <scale android:fromYScale="1.0" android:toYScale="0"
        android:fromXScale="1.0" android:toXScale="0" 



<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="">
    android:fromXScale="1.0" android:toXScale="0.8"
    android:fromYScale="1.0" android:toYScale="0.8"
    android:pivotX="50%p" android:pivotY="50%p"
    android:fromXScale="1.0" android:toXScale="0.0"
    android:fromYScale="1.0" android:toYScale="1.0"
    android:pivotX="50%p" android:pivotY="50%p"



<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="">
    android:fromXScale="0.0" android:toXScale="1.0"
    android:fromYScale="1.0" android:toYScale="1.0"
    android:pivotX="50%p" android:pivotY="50%p"

    android:fromXScale="0.8" android:toXScale="1.0"
    android:fromYScale="0.8" android:toYScale="1.0"
    android:pivotX="50%p" android:pivotY="50%p"



<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="">
    <alpha android:fromAlpha="0.0"



<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android=""
   android:fillAfter="true" >
       android:toYScale="3" >



<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android=""
   android:fillAfter="true" >
       android:toYScale="0.5" >



<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android=""
   android:fillAfter="true" >
       android:toAlpha="1.0" />



<set xmlns:android=""
   android:fillAfter="true" >
       android:toAlpha="0.0" />



<?xml version="1.0" encoding="utf-8"?>
       android:duration="1000" />



<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android=""
       android:toYScale="1.0" />



<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android=""
   android:fillAfter="true" >
       android:toYScale="0.0" />



<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android=""
       android:toYScale="1.0" />

Is there a standardized method to swap two variables in Python?

Does not work for multidimensional arrays, because references are used here.

import numpy as np

# swaps
data = np.random.random(2)
data[0], data[1] = data[1], data[0]

# does not swap
data = np.random.random((2, 2))
data[0], data[1] = data[1], data[0]

See also Swap slices of Numpy arrays

How do I check if I'm running on Windows in Python?

in sys too:

import sys
# its win32, maybe there is win64 too?
is_windows = sys.platform.startswith('win')

How to copy text to the client's clipboard using jQuery?

Copying to the clipboard is a tricky task to do in Javascript in terms of browser compatibility. The best way to do it is using a small flash. It will work on every browser. You can check it in this article.

Here's how to do it for Internet Explorer:

function copy (str)
    //for IE ONLY!

Extracting the last n characters from a string in R

Another reasonably straightforward way is to use regular expressions and sub:

sub('.*(?=.$)', '', string, perl=T)

So, "get rid of everything followed by one character". To grab more characters off the end, add however many dots in the lookahead assertion:

sub('.*(?=.{2}$)', '', string, perl=T)

where .{2} means .., or "any two characters", so meaning "get rid of everything followed by two characters".

sub('.*(?=.{3}$)', '', string, perl=T)

for three characters, etc. You can set the number of characters to grab with a variable, but you'll have to paste the variable value into the regular expression string:

n = 3
sub(paste('.+(?=.{', n, '})', sep=''), '', string, perl=T)

How to push changes to github after jenkins build completes?

I followed the below Steps. It worked for me.

In Jenkins execute shell under Build, creating a file and trying to push that file from Jenkins workspace to GitHub.

enter image description here

Download Git Publisher Plugin and Configure as shown below snapshot.

enter image description here

Click on Save and Build. Now you can check your git repository whether the file was pushed successfully or not.

Get LatLng from Zip Code - Google Maps API

<script src=""></script>
    var latitude = '';
    var longitude = '';

    var geocoder = new google.maps.Geocoder();
       componentRestrictions: { 
           country: 'IN', 
           postalCode: '744102'
    }, function (results, status) {
        if (status == google.maps.GeocoderStatus.OK) {
            latitude = results[0];
            longitude = results[0].geometry.location.lng();
            console.log(latitude + ", " + longitude);
        } else {
            alert("Request failed.")

How do I import modules or install extensions in PostgreSQL 9.1+?

For the postgrersql10

I have solved it with

yum install postgresql10-contrib

Don't forget to activate extensions in postgresql.conf

shared_preload_libraries = 'pg_stat_statements'
pg_stat_statements.track = all

then of course restart

systemctl restart postgresql-10.service 

all of the needed extensions you can find here


How to use JNDI DataSource provided by Tomcat in Spring?

With Spring's JavaConfig mechanism, you can do it like so:

public class MainConfig {


    DataSource dataSource() {
        DataSource dataSource = null;
        JndiTemplate jndi = new JndiTemplate();
        try {
            dataSource = jndi.lookup("java:comp/env/jdbc/yourname", DataSource.class);
        } catch (NamingException e) {
            logger.error("NamingException for java:comp/env/jdbc/yourname", e);
        return dataSource;


How to avoid scientific notation for large numbers in JavaScript?

I had the same issue with oracle returning scientic notation, but I needed the actual number for a url. I just used a PHP trick by subtracting zero, and I get the correct number.

for example 5.4987E7 is the val.

newval = val - 0;

newval now equals 54987000

how to print float value upto 2 decimal place without rounding off

i'd suggest shorter and faster approach:

printf("%.2f", ((signed long)(fVal * 100) * 0.01f));

this way you won't overflow int, plus multiplication by 100 shouldn't influence the significand/mantissa itself, because the only thing that really is changing is exponent.

PHP: How do you determine every Nth iteration of a loop?

Use the modulo arithmetic operation found here in the PHP manual.


$x = 3;

for($i=0; $i<10; $i++)
    if($i % $x == 0)
        // display image

For a more detailed understanding of modulus calculations, click here.

What exactly is Spring Framework for?

Spring framework is definitely good for web development and to be more specific for restful api services.

It is good for the above because of its dependency injection and integration with other modules like spring security, spring aop, mvc framework, microservices

With in any application, security is most probably a requirement.
If you aim to build a product that needs long maintenance, then you will need the utilize the Aop concept.

If your application has to much traffic thus increasing the load, you need to use the microservices concept.

Spring is giving all these features in one platform. Support with many modules.
Most importantly, spring is open source and an extensible framework,have a hook everywhere to integrate custom code in life cycle.

Spring Data is one project which provides integration with your project.

So spring can fit into almost every requirement.

How to run (not only install) an android application using .apk file?

if you're looking for the equivalent of "adb run myapp.apk"

you can use the script shown in this answer

(linux and mac only - maybe with cygwin on windows)

linux/mac users can also create a script to run an apk with something like the following:

create a file named "" with these 3 lines:

pkg=$(aapt dump badging $1|awk -F" " '/package/ {print $2}'|awk -F"'" '/name=/ {print $2}')
act=$(aapt dump badging $1|awk -F" " '/launchable-activity/ {print $2}'|awk -F"'" '/name=/ {print $2}')
adb shell am start -n $pkg/$act

then "chmod +x" to make it executable.

now you can simply: myapp.apk

The benefit here is that you don't need to know the package name or launchable activity name. Similarly, you can create " myapp.apk"

Note: This requires that you have aapt in your path. You can find it under the new build tools folder in the SDK

Combining node.js and Python

If you arrange to have your Python worker in a separate process (either long-running server-type process or a spawned child on demand), your communication with it will be asynchronous on the node.js side. UNIX/TCP sockets and stdin/out/err communication are inherently async in node.

Getting DOM node from React child element

this.props.children should either be a ReactElement or an array of ReactElement, but not components.

To get the DOM nodes of the children elements, you need to clone them and assign them a new ref.

render() {
  return (
      {, (element, idx) => {
        return React.cloneElement(element, { ref: idx });

You can then access the child components via this.refs[childIdx], and retrieve their DOM nodes via ReactDOM.findDOMNode(this.refs[childIdx]).

How to instantiate, initialize and populate an array in TypeScript?

A simple solution could be:

interface bar {
    length: number;

let bars: bar[];
bars = []; Connection refused

I would check:

  • Host name and port you're trying to connect to
  • The server side has managed to start listening correctly
  • There's no firewall blocking the connection

The simplest starting point is probably to try to connect manually from the client machine using telnet or Putty. If that succeeds, then the problem is in your client code. If it doesn't, you need to work out why it hasn't. Wireshark may help you on this front.

Static constant string (class member)

The current standard only allows such initialization for static constant integral types. So you need to do as AndreyT explained. However, that will be available in the next standard through the new member initialization syntax.

HTML&CSS + Twitter Bootstrap: full page layout or height 100% - Npx

Is this what you are looking for? Here is a fiddle demo.

The layout is based on percentage, colors are for clarity. If the content column overflows, a scrollbar should appear.

body, html, .container-fluid {
  height: 100%;

.navbar {

.article-tree {
  width: 25%;
  background: pink;

.content-area {
  overflow: auto;
  height: 100%;

.footer {
   background: red;
   height: 20px;

How to increase application heap size in Eclipse?

In the run configuration you want to customize (just click on it) open the tab Arguments and add -Xmx2048min the VM arguments section. You might want to set the -Xms as well (small heap size).

NuGet behind a proxy

Just in case you are using the https version of nuget (, be aware that you have to set the values with https.

  • https_proxy
  • https_proxy.user
  • https_proxy.password

How to add items into a numpy array

import numpy as np
a = np.array([[1,3,4],[1,2,3],[1,2,1]])
b = np.array([10,20,30])
c = np.hstack((a, np.atleast_2d(b).T))

returns c:

array([[ 1,  3,  4, 10],
       [ 1,  2,  3, 20],
       [ 1,  2,  1, 30]])

How to write a file or data to an S3 object using boto3

A cleaner and concise version which I use to upload files on the fly to a given S3 bucket and sub-folder-

import boto3

BUCKET_NAME = 'sample_bucket_name'
PREFIX = 'sub-folder/'

s3 = boto3.resource('s3')

# Creating an empty file called "_DONE" and putting it in the S3 bucket
s3.Object(BUCKET_NAME, PREFIX + '_DONE').put(Body="")

Note: You should ALWAYS put your AWS credentials (aws_access_key_id and aws_secret_access_key) in a separate file, for example- ~/.aws/credentials

What is referencedColumnName used for in JPA?

It is there to specify another column as the default id column of the other table, e.g. consider the following

  id int identity
  tableb_key varchar

  id int identity
  key varchar unique

// in class for TableA
@JoinColumn(name="tableb_key", referencedColumnName="key")

How to convert a byte array to a hex string in Java?

I found three different ways here:

The most elegant one, as he also notes, I think is this one:

static final String HEXES = "0123456789ABCDEF";
public static String getHex( byte [] raw ) {
    if ( raw == null ) {
        return null;
    final StringBuilder hex = new StringBuilder( 2 * raw.length );
    for ( final byte b : raw ) {
        hex.append(HEXES.charAt((b & 0xF0) >> 4))
            .append(HEXES.charAt((b & 0x0F)));
    return hex.toString();

1114 (HY000): The table is full

This error also appears if the partition on which tmpdir resides fills up (due to an alter table or other

how to get the value of a textarea in jquery?

you should use val() instead of html()

var message = $('#message').val();

XPath contains(text(),'some string') doesn't work when used with node with more than one Text subnode

[contains(text(),'')] only returns true or false. It won't return any element results.

What is a constant reference? (not a reference to a constant)

First I think int&const icr=i; is just int& icr = i, Modifier 'const' makes no sense(It just means you cannot make the reference refer to other variable).

const int x = 10;
// int& const y = x; // Compiler error here

Second, constant reference just means you cannot change the value of variable through reference.

const int x = 10;
const int& y = x;
//y = 20; // Compiler error here

Third, Constant references can bind right-value. Compiler will create a temp variable to bind the reference.

float x = 10;
const int& y = x;
const int& z = y + 10;
cout << (long long)&x << endl; //print 348791766212
cout << (long long)&y << endl; //print 348791766276
cout << (long long)&z << endl; //print 348791766340

How to generate unique id in MySQL?

I use UUID() to create a unique value.


insert into Companies (CompanyID, CompanyName) Values(UUID(), "TestUUID");

Adding and using header (HTTP) in nginx

You can use upstream headers (named starting with $http_) and additional custom headers. For example:

add_header X-Upstream-01 $http_x_upstream_01;
add_header X-Hdr-01  txt01;

next, go to console and make request with user's header:

curl -H "X-Upstream-01: HEADER1" -I http://localhost:11443/

the response contains X-Hdr-01, seted by server and X-Upstream-01, seted by client:

HTTP/1.1 200 OK
Server: nginx/1.8.0
Date: Mon, 30 Nov 2015 23:54:30 GMT
Content-Type: text/html;charset=UTF-8
Connection: keep-alive
X-Hdr-01: txt01
X-Upstream-01: HEADER1

How to change the font and font size of an HTML input tag?

<input type ="text" id="txtComputer">



Tesseract OCR simple example

Ok. I found the solution here tessnet2 fails to load the Ans given by Adam

Apparently i was using wrong version of tessdata. I was following the the source page instruction intuitively and that caused the problem.

it says

Quick Tessnet2 usage

  1. Download binary here, add a reference of the assembly Tessnet2.dll to your .NET project.

  2. Download language data definition file here and put it in tessdata directory. Tessdata directory and your exe must be in the same directory.

After you download the binary, when you follow the link to download the language file, there are many language files. but none of them are right version. you need to select all version and go to next page for correct version (tesseract-2.00.eng)! They should either update download binary link to version 3 or put the the version 2 language file on the first page. Or at least bold mention the fact that this version issue is a big deal!

Anyway I found it. Thanks everyone.

How to create an array containing 1...N

Array(...Array(9)).map((_, i) => i);_x000D_
console.log(Array(...Array(9)).map((_, i) => i))