Programs & Examples On #System administration

Map a network drive to be used by a service

You could us the 'net use' command:

var p = System.Diagnostics.Process.Start("net.exe", "use K: \\\\Server\\path");
var isCompleted = p.WaitForExit(5000);

If that does not work in a service, try the Winapi and PInvoke WNetAddConnection2

Edit: Obviously I misunderstood you - you can not change the sourcecode of the service, right? In that case I would follow the suggestion by mdb, but with a little twist: Create your own service (lets call it mapping service) that maps the drive and add this mapping service to the dependencies for the first (the actual working) service. That way the working service will not start before the mapping service has started (and mapped the drive).

What Process is using all of my disk IO

You're looking for iotop (assuming you've got kernel >2.6.20 and Python 2.5). Failing that, you're looking into hooking into the filesystem. I recommend the former.

How do I extract the contents of an rpm?

Did you try the rpm2cpio commmand? See the example below:

$ rpm2cpio php-5.1.4-1.esp1.x86_64.rpm | cpio -idmv


How do I get a list of locked users in an Oracle database?

select username,
  from dba_users 
 where lock_date is not null;

This will actually give you the list of locked users.

How do you uninstall the package manager "pip", if installed from source?

That way you haven't installed pip, you installed just the easy_install i.e. setuptools.

First you should remove all the packages you installed with easy_install using (see uninstall):

easy_install -m PackageName

This includes pip if you installed it using easy_install pip.

After this you remove the setuptools following the instructions from here:

If setuptools package is found in your global site-packages directory, you may safely remove the following file/directory:


If setuptools is installed in some other location such as the user site directory (eg: ~/.local, ~/Library/Python or %APPDATA%), then you may safely remove the following files:

JavaScript load a page on button click

Just window.location = "", or, for local links, window.location = "my_relative_link.html".

You can try it by typing it into your address bar as well, e.g. javascript: window.location = "".

Also note that the protocol part of the URL (http://) is not optional for absolute links; omitting it will make javascript assume a relative link.

Everytime I run gulp anything, I get a assertion error. - Task function must be specified

You don't need to downgrade your gulp from gulp 4. Use gulp.series() to combine multiple tasks. At first install gulp globally with

npm install --global gulp-cli

and then install locally on your working directory with

npm install --save-dev gulp

see details here



  "name": "gulp-test",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  "author": "",
  "license": "ISC",
  "devDependencies": {
    "browser-sync": "^2.26.3",
    "gulp": "^4.0.0",
    "gulp-sass": "^4.0.2"
  "dependencies": {
    "bootstrap": "^4.3.1",
    "jquery": "^3.3.1",
    "popper.js": "^1.14.7"


var gulp = require("gulp");
var sass = require('gulp-sass');
var browserSync = require('browser-sync').create();

// Specific Task
function js() {
    return gulp
    .src(['node_modules/bootstrap/dist/js/bootstrap.min.js', 'node_modules/jquery/dist/jquery.min.js', 'node_modules/popper.js/dist/umd/popper.min.js'])

// Specific Task
function gulpSass() {
    return gulp

// Run multiple tasks
gulp.task('start', gulp.series(js, gulpSass));

Run gulp start to fire multiple tasks & run gulp js or gulp gulpSass for specific task.

Java 8 Filter Array Using Lambda

even simpler, adding up to String[],

use built-in filter filter(StringUtils::isNotEmpty) of org.apache.commons.lang3

import org.apache.commons.lang3.StringUtils;

    String test = "a\nb\n\nc\n";
    String[] lines = test.split("\\n", -1);

    String[]  result =[]::new);

and output: [a, b, , c, ] [a, b, c]

How do I make a Docker container start automatically on system boot?

You can use docker update --restart=on-failure <container ID or name>.

On top of what the name suggests, on-failure will not only restart the container on failure, but also at system boot.

Per the documentation, there are multiple restart options:

Flag            Description
no              Do not automatically restart the container. (the default)
on-failure      Restart the container if it exits due to an error, which manifests as a non-zero exit code.
always          Always restart the container if it stops. If it is manually stopped, it is restarted only when Docker daemon restarts or the container itself is manually restarted. (See the second bullet listed in restart policy details)
unless-stopped  Similar to always, except that when the container is stopped (manually or otherwise), it is not restarted even after Docker daemon restarts.

How to use variables in SQL statement in Python?

Many ways. DON'T use the most obvious one (%s with %) in real code, it's open to attacks.

Here copy-paste'd from pydoc of sqlite3:

# Never do this -- insecure!
symbol = 'RHAT'
c.execute("SELECT * FROM stocks WHERE symbol = '%s'" % symbol)

# Do this instead
t = ('RHAT',)
c.execute('SELECT * FROM stocks WHERE symbol=?', t)
print c.fetchone()

# Larger example that inserts many records at a time
purchases = [('2006-03-28', 'BUY', 'IBM', 1000, 45.00),
             ('2006-04-05', 'BUY', 'MSFT', 1000, 72.00),
             ('2006-04-06', 'SELL', 'IBM', 500, 53.00),
c.executemany('INSERT INTO stocks VALUES (?,?,?,?,?)', purchases)

More examples if you need:

# Multiple values single statement/execution
c.execute('SELECT * FROM stocks WHERE symbol=? OR symbol=?', ('RHAT', 'MSO'))
print c.fetchall()
c.execute('SELECT * FROM stocks WHERE symbol IN (?, ?)', ('RHAT', 'MSO'))
print c.fetchall()
# This also works, though ones above are better as a habit as it's inline with syntax of executemany().. but your choice.
c.execute('SELECT * FROM stocks WHERE symbol=? OR symbol=?', 'RHAT', 'MSO')
print c.fetchall()
# Insert a single item
c.execute('INSERT INTO stocks VALUES (?,?,?,?,?)', ('2006-03-28', 'BUY', 'IBM', 1000, 45.00))

Opening XML page shows "This XML file does not appear to have any style information associated with it."

This XML file does not appear to have any style information associated with it. The document tree is shown below.

You will get this error in the client side when the client (the webbrowser) for some reason interprets the HTTP response content as text/xml instead of text/html and the parsed XML tree doesn't have any XML-stylesheet. In other words, the webbrowser incorrectly parsed the retrieved HTTP response content as XML instead of as HTML due to the wrong or missing HTTP response content type.

In case of JSF/Facelets files which have the default extension of .xhtml, that can in turn happen if the HTTP request hasn't invoked the FacesServlet and thus it wasn't able to parse the Facelets file and generate the desired HTML output based on the XHTML source code. Firefox is then merely guessing the HTTP response content type based on the .xhtml file extension which is in your Firefox configuration apparently by default interpreted as text/xml.

You need to make sure that the HTTP request URL, as you see in browser's address bar, matches the <url-pattern> of the FacesServlet as registered in webapp's web.xml, so that it will be invoked and be able to generate the desired HTML output based on the XHTML source code. If it's for example *.jsf, then you need to open the page by /some.jsf instead of /some.xhtml. Alternatively, you can also just change the <url-pattern> to *.xhtml. This way you never need to fiddle with virtual URLs.

See also:

Note thus that you don't actually need a XML stylesheet. This all was just misinterpretation by the webbrowser while trying to do its best to make something presentable out of the retrieved HTTP response content. It should actually have retrieved the properly generated HTML output, Firefox surely knows precisely how to deal with HTML content.

Can't load IA 32-bit .dll on a AMD 64-bit platform

Had same issue in win64bit and JVM 64bit

Was solved by uploading dll to system32

Replace CRLF using powershell

You have not specified the version, I'm assuming you are using Powershell v3.

Try this:

$path = "C:\Users\abc\Desktop\File\abc.txt"
(Get-Content $path -Raw).Replace("`r`n","`n") | Set-Content $path -Force

Editor's note: As mike z points out in the comments, Set-Content appends a trailing CRLF, which is undesired. Verify with: 'hi' > t.txt; (Get-Content -Raw t.txt).Replace("`r`n","`n") | Set-Content t.txt; (Get-Content -Raw t.txt).EndsWith("`r`n"), which yields $True.

Note this loads the whole file in memory, so you might want a different solution if you want to process huge files.


This might work for v2 (sorry nowhere to test):

$in = "C:\Users\abc\Desktop\File\abc.txt"
$out = "C:\Users\abc\Desktop\File\abc-out.txt"
(Get-Content $in) -join "`n" > $out

Editor's note: Note that this solution (now) writes to a different file and is therefore not equivalent to the (still flawed) v3 solution. (A different file is targeted to avoid the pitfall Ansgar Wiechers points out in the comments: using > truncates the target file before execution begins). More importantly, though: this solution too appends a trailing CRLF, which may be undesired. Verify with 'hi' > t.txt; (Get-Content t.txt) -join "`n" > t.NEW.txt; [io.file]::ReadAllText((Convert-Path t.NEW.txt)).endswith("`r`n"), which yields $True.

Same reservation about being loaded to memory though.

How to get value by key from JObject?

Try this:

private string GetJArrayValue(JObject yourJArray, string key)
    foreach (KeyValuePair<string, JToken> keyValuePair in yourJArray)
        if (key == keyValuePair.Key)
            return keyValuePair.Value.ToString();

Checking if a key exists in a JS object

var obj = {
    "key1" : "k1",
    "key2" : "k2",
    "key3" : "k3"

if ("key1" in obj)
    console.log("has key1 in obj");


To access a child key of another key

var obj = {
    "key1": "k1",
    "key2": "k2",
    "key3": "k3",
    "key4": {
        "keyF": "kf"

if ("keyF" in obj.key4)
    console.log("has keyF in obj");

Fatal error: Call to undefined function mcrypt_encrypt()

You don't have the mcrypt library installed.

See for more information.

If you are on shared hosting, you can ask your provider to install it.

In OSX you can easily install mcrypt via homebrew

brew install php54-mcrypt --without-homebrew-php

Then add this line to /etc/php.ini.


How to get the selected radio button’s value?

Using a pure javascript, you can handle the reference to the object that dispatched the event.

function (event) {

Detect whether there is an Internet connection available on Android

The getActiveNetworkInfo() method of ConnectivityManager returns a NetworkInfo instance representing the first connected network interface it can find or null if none if the interfaces are connected. Checking if this method returns null should be enough to tell if an internet connection is available.

private boolean isNetworkAvailable() {
     ConnectivityManager connectivityManager = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
     NetworkInfo activeNetworkInfo = connectivityManager.getActiveNetworkInfo();
     return activeNetworkInfo != null; 

You will also need:

in your android manifest.


Note that having an active network interface doesn't guarantee that a particular networked service is available. Networks issues, server downtime, low signal, captive portals, content filters and the like can all prevent your app from reaching a server. For instance you can't tell for sure if your app can reach Twitter until you receive a valid response from the Twitter service.

getActiveNetworkInfo() shouldn't never give null. I don't know what they were thinking when they came up with that. It should give you an object always.

How to create a label inside an <input> element?

Here is a simple example, all it does is overlay an image (with whatever wording you want). I saw this technique somewhere. I am using the prototype library so you would need to modify if using something else. With the image loading after window.load it fails gracefully if javascript is disabled.

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "" >
<html xmlns="" >
    <meta http-equiv="content-type" content="text/html; charset=ISO-8859-1;" />
    <meta http-equiv="Expires" content="Fri, Jan 1 1981 08:00:00 GMT" />
    <meta http-equiv="Pragma" content="no-cache" />
    <meta http-equiv="Cache-Control" content="no-cache" />
    <style type="text/css" >

            background-image: url(/images/search_back.png);
            background-repeat: no-repeat;
            background-attachment: scroll;
            background-x-position: left;
            background-y-position: center;


    <script type="text/javascript" src="/logist/include/scripts/js/prototype.js" ></script>
    <input type="text" id="q" name="q" value="" />

    <script type="text/javascript" language="JavaScript" >
    //  <![CDATA[
        function f(e){

        function b(e){
            if ( $F('q') == '' )

        Event.observe( 'q', 'focus', f);
        Event.observe( 'q', 'blur', b);
        Event.observe( window, 'load', b);

    //  ]]>

IBOutlet and IBAction

Ran into the diagram while looking at key-value coding, thought it might help someone. It helps with understanding of what IBOutlet is.

By looking at the flow, one could see that IBOutlets are only there to match the property name with a control name in the Nib file.

How nib file is loaded, screenshot of Matt's online book for iOS6

Material Design not styling alert dialogs

UPDATED ON Aug 2019 WITH The Material components for android library:

With the new Material components for Android library you can use the new class, which extends from the existing androidx.appcompat.AlertDialog.Builder class and provides support for the latest Material Design specifications.

Just use something like this:

new MaterialAlertDialogBuilder(context)
            .setMessage("Lorem ipsum dolor ....")
            .setPositiveButton("Ok", /* listener = */ null)
            .setNegativeButton("Cancel", /* listener = */ null)

You can customize the colors extending the ThemeOverlay.MaterialComponents.MaterialAlertDialog style:

  <style name="CustomMaterialDialog" parent="@style/ThemeOverlay.MaterialComponents.MaterialAlertDialog">
     <!-- Background Color-->
     <item name="android:background">#006db3</item>
     <!-- Text Color for title and message -->
     <item name="colorOnSurface">@color/secondaryColor</item>
     <!-- Text Color for buttons -->
     <item name="colorPrimary">@color/white</item> 

To apply your custom style just use the constructor:

new MaterialAlertDialogBuilder(context,

enter image description here

To customize the buttons, the title and the body text check this post for more details.

You can also change globally the style in your app theme:

 <!-- Base application theme. -->
 <style name="AppTheme" parent="Theme.MaterialComponents.Light">
    <item name="materialAlertDialogTheme">@style/CustomMaterialDialog</item>


With the new AppCompat v22.1 you can use the new

Just use a code like this:


AlertDialog.Builder builder =
       new AlertDialog.Builder(this,;
builder.setMessage("Lorem ipsum dolor ....");
builder.setPositiveButton("OK", null);
builder.setNegativeButton("Cancel", null);;

And use a style like this:

<style name="AppCompatAlertDialogStyle" parent="Theme.AppCompat.Light.Dialog.Alert">
        <item name="colorAccent">#FFCC00</item>
        <item name="android:textColorPrimary">#FFFFFF</item>
        <item name="android:background">#5fa3d0</item>

Otherwise you can define in your current theme:

<style name="AppTheme" parent="Theme.AppCompat.Light">
    <!-- your style -->
    <item name="alertDialogTheme">@style/AppCompatAlertDialogStyle</item>

and then in your code:


    AlertDialog.Builder builder =
           new AlertDialog.Builder(this);

Here the AlertDialog on Kitkat: enter image description here

How to add Apache HTTP API (legacy) as compile-time dependency to build.grade for Android M?

Just copied file: org.apache.http.legacy.jar from Android/Sdk/platforms/android-23/optional folder into project folder app/libs.

Worked like charm for 23.1.1.

Windows service on Local Computer started and then stopped error

You may want to unit test the initialization - but because it's in the OnStart method this is near to impossible. I would suggest moving the initialization code out into a separate class so that it can be tested or at least re-used in a form tester.

Secondly to add some logging (using Log4Net or similar) and add some verbose logging so that you can see details about runtime errors. Examples of runtime errors would be AccessViolation etc. especially if your service is running without enough privileges to access the config files.

Cannot GET / Nodejs Error

Have you checked your folder structure? It seems to me like Express can't find your root directory, which should be a a folder named "site" right under your default directory. Here is how it should look like, according to the tutorial:


For example on my machine, I started getting the same error as you when I renamed my "site" folder as something else. So I would suggest you check that you have the index.html page inside a "site" folder that sits on the same path as your server.js file.

Hope that helps!

How do I redirect to another webpage?

This is very easy to implement. You can use:

window.location.href = "";

This will remember the history of the previous page. So one can go back by clicking on the browser's back button.



This method does not remember the history of the previous page. The back button becomes disabled in this case.

What is the difference between spark.sql.shuffle.partitions and spark.default.parallelism?

spark.default.parallelism is the default number of partition set by spark which is by default 200. and if you want to increase the number of partition than you can apply the property spark.sql.shuffle.partitions to set number of partition in the spark configuration or while running spark SQL.

Normally this spark.sql.shuffle.partitions it is being used when we have a memory congestion and we see below error: spark error:java.lang.IllegalArgumentException: Size exceeds Integer.MAX_VALUE

so set your can allocate a partition as 256 MB per partition and that you can use to set for your processes.

also If number of partitions is near to 2000 then increase it to more than 2000. As spark applies different logic for partition < 2000 and > 2000 which will increase your code performance by decreasing the memory footprint as data default is highly compressed if >2000.

Current user in Magento?

Found under "app/code/core/Mage/Page/Block/Html/Header.php":

public function getWelcome()
    if (empty($this->_data['welcome'])) {
        if (Mage::app()->isInstalled() && Mage::getSingleton('customer/session')->isLoggedIn()) {
            $this->_data['welcome'] = $this->__('Welcome, %s!', Mage::getSingleton('customer/session')->getCustomer()->getName());
        } else {
            $this->_data['welcome'] = Mage::getStoreConfig('design/header/welcome');

    return $this->_data['welcome'];

So it looks like Mage::getSingleton('customer/session')->getCustomer() will get your current logged in customer ;)

To get the currently logged in admin:


How to add title to seaborn boxplot

sns.boxplot() function returns Axes(matplotlib.axes.Axes) object. please refer the documentation you can add title using 'set' method as below:

sns.boxplot('Day', 'Count', data=gg).set(title='lalala')

you can also add other parameters like xlabel, ylabel to the set method.

sns.boxplot('Day', 'Count', data=gg).set(title='lalala', xlabel='its x_label', ylabel='its y_label')

There are some other methods as mentioned in the matplotlib.axes.Axes documentaion to add tile, legend and labels.

Laravel - htmlspecialchars() expects parameter 1 to be string, object given

Laravel - htmlspecialchars() expects parameter 1 to be string, object given.

thank me latter.........................

when you send or get array from contrller or function but try to print as single value or single variable in laravel blade file so it throws an error

->use any think who convert array into string it work.

solution: 1)run the foreach loop and get single single value and print. 2)The implode() function returns a string from the elements of an array. {{ implode($your_variable,',') }}

implode is best way to do it and its 100% work.

What is a software framework?

Technically, you don't need a framework. If you're making a really really simple site (think of the web back in 1992), you can just do it all with hard-coded HTML and some CSS.

And if you want to make a modern webapp, you don't actually need to use a framework for that, either.

You can instead choose to write all of the logic you need yourself, every time. You can write your own data-persistence/storage layer, or - if you're too busy - just write custom SQL for every single database access. You can write your own authentication and session handling layers. And your own template rending logic. And your own exception-handling logic. And your own security functions. And your own unit test framework to make sure it all works fine. And your own... [goes on for quite a long time]

Then again, if you do use a framework, you'll be able to benefit from the good, usually peer-reviewed and very well tested work of dozens if not hundreds of other developers, who may well be better than you. You'll get to build what you want rapidly, without having to spend time building or worrying too much about the infrastructure items listed above.

You can get more done in less time, and know that the framework code you're using or extending is very likely to be done better than you doing it all yourself.

And the cost of this? Investing some time learning the framework. But - as virtually every web dev out there will attest - it's definitely worth the time spent learning to get massive (really, massive) benefits from using whatever framework you choose.

Replacing accented characters php

It's worked like magically, i have used only array, this pattern is worked for me. check this pattern

Get Today's date in Java at midnight time

If you are able to add external libs to your project. I would recommend that you try out Joda-time. It has a very clever way of working with dates.

Add Foreign Key relationship between two Databases

In my experience, the best way to handle this when the primary authoritative source of information for two tables which are related has to be in two separate databases is to sync a copy of the table from the primary location to the secondary location (using T-SQL or SSIS with appropriate error checking - you cannot truncate and repopulate a table while it has a foreign key reference, so there are a few ways to skin the cat on the table updating).

Then add a traditional FK relationship in the second location to the table which is effectively a read-only copy.

You can use a trigger or scheduled job in the primary location to keep the copy updated.

Working with select using AngularJS's ng-options

I hope the following will work for you.

<select class="form-control"
        ng-options=" + ' (' + (option.price | currency:'USD$') + ')' for option in options">

SQL query to select distinct row with minimum value

SELECT * from room
  select DISTINCT hotelNo, MIN(price) MinPrice
  from room
 Group by hotelNo
  ) NewT   
 on room.hotelNo = NewT.hotelNo and room.price = NewT.MinPrice;

Convert any object to a byte[]

Using Encoding.UTF8.GetBytes is faster than using MemoryStream. Here, I am using NewtonsoftJson to convert input object to JSON string and then getting bytes from JSON string.

byte[] SerializeObject(object value) =>Encoding.UTF8.GetBytes(JsonConvert.SerializeObject(value));

Benchmark for @Daniel DiPaolo's version with this version

Method                    |     Mean |     Error |    StdDev |   Median |  Gen 0 | Allocated |
ObjectToByteArray         | 4.983 us | 0.1183 us | 0.2622 us | 4.887 us | 0.9460 |    3.9 KB |
ObjectToByteArrayWithJson | 1.548 us | 0.0309 us | 0.0690 us | 1.528 us | 0.3090 |   1.27 KB |

Exit Shell Script Based on Process Exit Code

  1. How do I get the exit code of cmd1 in cmd1|cmd2

    First, note that cmd1 exit code could be non-zero and still don't mean an error. This happens for instance in

    cmd | head -1

    You might observe a 141 (or 269 with ksh93) exit status of cmd1, but it's because cmd was interrupted by a SIGPIPE signal when head -1 terminated after having read one line.

    To know the exit status of the elements of a pipeline cmd1 | cmd2 | cmd3

    a. with Z shell (zsh):

    The exit codes are provided in the pipestatus special array. cmd1 exit code is in $pipestatus[1], cmd3 exit code in $pipestatus[3], so that $? is always the same as $pipestatus[-1].

    b. with Bash:

    The exit codes are provided in the PIPESTATUS special array. cmd1 exit code is in ${PIPESTATUS[0]}, cmd3 exit code in ${PIPESTATUS[2]}, so that $? is always the same as ${PIPESTATUS: -1}.


    For more details see Z shell.

How do I build an import library (.lib) AND a DLL in Visual C++?

OK, so I found the answer from says that this problem was caused by not exporting any symbols and further instructs on how to export symbols to create the lib file. To do so, add the following code to your .h file for your DLL.

#define BARNABY_API __declspec(dllexport)
#define BARNABY_API __declspec(dllimport)

Where BARNABY_EXPORTS and BARNABY_API are unique definitions for your project. Then, each function you export you simply precede by:

BARNABY_API int add(){

This problem could have been prevented either by clicking the Export Symbols box on the new project DLL Wizard or by voting yes for lobotomies for computer programmers.

The tilde operator in Python

Besides being a bitwise complement operator, ~ can also help revert a boolean value, though it is not the conventional bool type here, rather you should use numpy.bool_.

This is explained in,

import numpy as np
assert ~np.True_ == np.False_

Reversing logical value can be useful sometimes, e.g., below ~ operator is used to cleanse your dataset and return you a column without NaN.

from numpy import NaN
import pandas as pd

matrix = pd.DataFrame([1,2,3,4,NaN], columns=['Number'], dtype='float64')
# Remove NaN in column 'Number'

Windows service with timer

First approach with Windows Service is not easy..

A long time ago, I wrote a C# service.

This is the logic of the Service class (tested, works fine):

namespace MyServiceApp
    public class MyService : ServiceBase
        private System.Timers.Timer timer;

        protected override void OnStart(string[] args)
            this.timer = new System.Timers.Timer(30000D);  // 30000 milliseconds = 30 seconds
            this.timer.AutoReset = true;
            this.timer.Elapsed += new System.Timers.ElapsedEventHandler(this.timer_Elapsed);

        protected override void OnStop()
            this.timer = null;

        private void timer_Elapsed(object sender, System.Timers.ElapsedEventArgs e)
            MyServiceApp.ServiceWork.Main(); // my separate static method for do work

        public MyService()
            this.ServiceName = "MyService";

        // service entry point
        static void Main()
            System.ServiceProcess.ServiceBase.Run(new MyService());

I recommend you write your real service work in a separate static method (why not, in a console application...just add reference to it), to simplify debugging and clean service code.

Make sure the interval is enough, and write in log ONLY in OnStart and OnStop overrides.

Hope this helps!

PHP cURL custom headers

Use the following Syntax

$ch = curl_init();
curl_setopt($ch, CURLOPT_URL,"");
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_POSTFIELDS,$vars);  //Post Fields
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);

$headers = [
    'X-Apple-Tz: 0',
    'X-Apple-Store-Front: 143444,12',
    'Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8',
    'Accept-Encoding: gzip, deflate',
    'Accept-Language: en-US,en;q=0.5',
    'Cache-Control: no-cache',
    'Content-Type: application/x-www-form-urlencoded; charset=utf-8',
    'Referer:', //Your referrer address
    'User-Agent: Mozilla/5.0 (X11; Ubuntu; Linux i686; rv:28.0) Gecko/20100101 Firefox/28.0',
    'X-MicrosoftAjax: Delta=true'

curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);

$server_output = curl_exec ($ch);

curl_close ($ch);

print  $server_output ;

How to put a List<class> into a JSONObject and then read that object?

Call getJSONObject() instead of getString(). That will give you a handle on the JSON object in the array and then you can get the property off of the object from there.

For example, to get the property "value" from a List<SomeClass> where SomeClass has a String getValue() and setValue(String value):

JSONObject obj = new JSONObject();
List<SomeClass> sList = new ArrayList<SomeClass>();

SomeClass obj1 = new SomeClass();

SomeClass obj2 = new SomeClass();

obj.put("list", sList);

JSONArray jArray = obj.getJSONArray("list");
for(int ii=0; ii < jArray.length(); ii++)

How to print last two columns using awk

try with this

$ cat /tmp/topfs.txt
/dev/sda2      xfs        32G   10G   22G  32% /

awk print last column
$ cat /tmp/topfs.txt | awk '{print $NF}'

awk print before last column
$ cat /tmp/topfs.txt | awk '{print $(NF-1)}'

awk - print last two columns
$ cat /tmp/topfs.txt | awk '{print $(NF-1), $NF}'
32% /

How can I convert my Java program to an .exe file?

You can convert jar to exe using jar2exe. However you need to purchase the software. If you need a open source software i would suggest JSmooth.

How can I transition height: 0; to height: auto; using CSS?

I've been looking at this issue for a while today and came across this solution:

Use max-height and dynamically set the max-height based upon the calculated height of the contents of the container

$(obj).children().each(function(index, element) {
   InnerHeight += $(this).height();

to animate to full size:

$(obj).removeClass('collapsed').css('max-height', InnerHeight);

to animate to smaller size:

$(obj).removeClass('collapsed').css('max-height', MySmallerHeight);

use CSS3 transition:max-height;

This way you avoid the glitchy looking animation from way to large of a height AND you dont run the risk of clipping your content.

The ALTER TABLE statement conflicted with the FOREIGN KEY constraint

It occurred because you tried to create a foreign key from tblDomare.PersNR to tblBana.BanNR but/and the values in tblDomare.PersNR didn't match with any of the values in tblBana.BanNR. You cannot create a relation which violates referential integrity.

print spaces with String.format()

int numberOfSpaces = 3;
String space = String.format("%"+ numberOfSpaces +"s", " ");

scale fit mobile web content using viewport meta tag

ok, here is my final solution with 100% native javascript:

<meta id="viewport" name="viewport">

<script type="text/javascript">
//mobile viewport hack

  function apply_viewport(){
    if( /Android|webOS|iPhone|iPad|iPod|BlackBerry/i.test(navigator.userAgent)   ) {

      var ww = window.screen.width;
      var mw = 800; // min width of site
      var ratio =  ww / mw; //calculate ratio
      var viewport_meta_tag = document.getElementById('viewport');
      if( ww < mw){ //smaller than minimum size
        viewport_meta_tag.setAttribute('content', 'initial-scale=' + ratio + ', maximum-scale=' + ratio + ', minimum-scale=' + ratio + ', user-scalable=no, width=' + mw);
      else { //regular size
        viewport_meta_tag.setAttribute('content', 'initial-scale=1.0, maximum-scale=1, minimum-scale=1.0, user-scalable=yes, width=' + ww);

  //ok, i need to update viewport scale if screen dimentions changed
  window.addEventListener('resize', function(){



How to get exact browser name and version?

Use get_browser()

From Manual:

echo $_SERVER['HTTP_USER_AGENT'] . "\n\n";

$browser = get_browser(null, true);

Will return:

    [browser_name_regex] => ^mozilla/5\.0 (windows; .; windows nt 5\.1; .*rv:.*) gecko/.* firefox/0\.9.*$
    [browser_name_pattern] => Mozilla/5.0 (Windows; ?; Windows NT 5.1; *rv:*) Gecko/* Firefox/0.9*/
    [parent] => Firefox 0.9
    [platform] => WinXP
    [browser] => Firefox
    [version] => 0.9
    [majorver] => 0
    [minorver] => 9
    [cssversion] => 2
    [frames] => 1
    [iframes] => 1
    [tables] => 1
    [cookies] => 1
    [backgroundsounds] =>
    [vbscript] =>
    [javascript] => 1
    [javaapplets] => 1
    [activexcontrols] =>
    [cdf] =>
    [aol] =>
    [beta] => 1
    [win16] =>
    [crawler] =>
    [stripper] =>
    [wap] =>
    [netclr] =>

ASP.NET MVC - passing parameters to the controller

Or, you could try changing the parameter type to string, then convert the string to an integer in the method. I am new to MVC, but I believe you need nullable objects in your parameter list, how else will the controller indicate that no such parameter was provided? So...

public ActionResult ViewNextItem(string id)...

org.json.simple.JSONArray cannot be cast to org.json.simple.JSONObject

JSONObject site=jsonSites.getJSONObject(i) should work out

SQL Server: Multiple table joins with a WHERE clause

SELECT Computer.Computer_Name, Application1.Name, Max(Soft.[Version]) as Version1
FROM Application1
inner JOIN Software
    ON Application1.ID = Software.Application_Id
cross join Computer
Left JOIN Software_Computer
    ON Software_Computer.Computer_Id = Computer.ID and Software_Computer.Software_Id = Software.Id
Left JOIN Software as Soft
    ON Soft.Id = Software_Computer.Software_Id
WHERE Computer.ID = 1 
GROUP BY Computer.Computer_Name, Application1.Name 

How to change environment's font size?

Press Ctrl and use the mouse wheel to zoom In or Out.

Generate full SQL script from EF 5 Code First Migrations

For anyone using entity framework core ending up here. This is how you do it.

# Powershell / Package manager console

# Cli 
dotnet ef migrations script

You can use the -From and -To parameter to generate an update script to update a database to a specific version.

Script-Migration -From 20190101011200_Initial-Migration -To 20190101021200_Migration-2

There are several options to this command.

The from migration should be the last migration applied to the database before running the script. If no migrations have been applied, specify 0 (this is the default).

The to migration is the last migration that will be applied to the database after running the script. This defaults to the last migration in your project.

An idempotent script can optionally be generated. This script only applies migrations if they haven't already been applied to the database. This is useful if you don't exactly know what the last migration applied to the database was or if you are deploying to multiple databases that may each be at a different migration.

How to set default Checked in checkbox ReactJS?

Here's a code I did some time ago, it might be useful. you have to play with this line => this.state = { checked: false, checked2: true};

class Componente extends React.Component {
  constructor(props) {

    this.state = { checked: false, checked2: true};
    this.handleChange = this.handleChange.bind(this);
    this.handleChange2 = this.handleChange2.bind(this);


  handleChange() {
        checked: !this.state.checked      

  handleChange2() {
        checked2: !this.state.checked2      

  render() {
    const togglecheck1 = this.state.checked ? 'hidden-check1' : '';
    const togglecheck2 = this.state.checked2 ? 'hidden-check2' : '';

    return <div>
        <label>Check 1</label>
        <input type="checkbox" id="chk1"className="chk11" checked={ this.state.checked } onChange={ this.handleChange } />
        <label>Check 2</label>
        <input type="checkbox" id="chk2" className="chk22" checked={ this.state.checked2 } onChange={ this.handleChange2 } />

      <div className={ togglecheck1 }>show hide div with check 1</div>
      <div className={ togglecheck2 }>show hide div with check 2</div>


  <Componente />,


.hidden-check1 {
  display: none;  

.hidden-check2 {
  visibility: hidden;


  <div id="container">
      <!-- This element's contents will be replaced with your component. -->

here's the codepen =>

How do I change the value of a global variable inside of a function

var a = 10;


function myFunction(){
   a = 20;

alert("Value of 'a' outside the function " + a); //outputs 20

How do I decode a string with escaped unicode?

Using JSON.decode for this comes with significant drawbacks that you must be aware of:

  • You must wrap the string in double quotes
  • Many characters are not supported and must be escaped themselves. For example, passing any of the following to JSON.decode (after wrapping them in double quotes) will error even though these are all valid: \\n, \n, \\0, a"a
  • It does not support hexadecimal escapes: \\x45
  • It does not support Unicode code point sequences: \\u{045}

There are other caveats as well. Essentially, using JSON.decode for this purpose is a hack and doesn't work the way you might always expect. You should stick with using the JSON library to handle JSON, not for string operations.

I recently ran into this issue myself and wanted a robust decoder, so I ended up writing one myself. It's complete and thoroughly tested and is available here: It mimics the JavaScript standard as closely as possible.


The source is about 250 lines so I won't include it all here, but essentially it uses the following Regex to find all escape sequences and then parses them using parseInt(string, 16) to decode the base-16 numbers and then String.fromCodePoint(number) to get the corresponding character:


Commented (NOTE: This regex matches all escape sequences, including invalid ones. If the string would throw an error in JS, it throws an error in my library [ie, '\x!!' will error]):

\\ # All escape sequences start with a backslash
(?: # Starts a group of 'or' statements
(\\) # If a second backslash is encountered, stop there (it's an escaped slash)
| # or
x([\s\S]{0,2}) # Match valid hexadecimal sequences
| # or
u(\{[^}]*\}?) # Match valid code point sequences
| # or
u([\s\S]{4})\\u([^{][\s\S]{0,3}) # Match surrogate code points which get parsed together
| # or
u([\s\S]{0,4}) # Match non-surrogate Unicode sequences
| # or
([0-3]?[0-7]{1,2}) # Match deprecated octal sequences
| # or
([\s\S]) # Match anything else ('.' doesn't match newlines)
| # or
$ # Match the end of the string
) # End the group of 'or' statements
/g # Match as many instances as there are


Using that library:

import unraw from "unraw";

let step1 = unraw('http\\u00253A\\u00252F\\');
// yields ""
// Then you can use decodeURIComponent to further decode it:
let step2 = decodeURIComponent(step1);
// yields

How to avoid warning when introducing NAs by coercion

Use suppressWarnings():

suppressWarnings(as.numeric(c("1", "2", "X")))
[1]  1  2 NA

This suppresses warnings.

READ_EXTERNAL_STORAGE permission for Android

In addition of all answers. You can also specify the minsdk to apply with this annotation


I used this in order to accept this request even my minsdk is 18. What it does is that the method only runs when device targets "_apilevel_" and upper. Here's my method:

void solicitarPermisos(){

    if (ContextCompat.checkSelfPermission(this,permiso)
            != PackageManager.PERMISSION_GRANTED) {

        // Should we show an explanation?
        if (shouldShowRequestPermissionRationale(
                Manifest.permission.READ_EXTERNAL_STORAGE)) {
            // Explain to the user why we need to read the contacts

        requestPermissions(new String[]{Manifest.permission.READ_EXTERNAL_STORAGE},

        // app-defined int constant that should be quite unique




if not exists (select * from sysobjects where name='cars' and xtype='U')
    create table cars (
        Name varchar(64) not null

The above will create a table called cars if the table does not already exist.

Dynamic button click event handler

Some code for a variation on this problem. Using the above code got me my click events as needed, but I was then stuck trying to work out which button had been clicked. My scenario is I have a dynamic amount of tab pages. On each tab page are (all dynamically created) 2 charts, 2 DGVs and a pair of radio buttons. Each control has a unique name relative to the tab, but there could be 20 radio buttons with the same name if I had 20 tab pages. The radio buttons switch between which of the 2 graphs and DGVs you get to see. Here is the code for when one of the radio buttons gets checked (There's a nearly identical block that swaps the charts and DGVs back):

   Private Sub radioFit_Components_CheckedChanged(ByVal sender As System.Object, ByVal e As System.EventArgs)

    If = "radioFit_Components" And sender.visible Then
        If sender.checked Then
            For Each ctrl As Control In TabControl1.SelectedTab.Controls
                Select Case ctrl.Name
                    Case "embChartSSE_Components"
                    Case "embChartSSE_Fit_Curve"
                    Case "dgvFit_Components"
                End Select

        End If
    End If

End Sub

This code will fire for any of the tab pages and swap the charts and DGVs over on any of the tab pages. The sender.visible check is to stop the code firing when the form is being created.

Installing a specific version of angular with angular cli

npx @angular/cli@10 new my-poject

you can replace 10 with your version of choice... no need to uninstall your existing CLI! Just learnt that now...

HTML input file selection event not firing upon selecting the same file

Clearing the value of 0th index of input worked for me. Please try the below code, hope this will work (AngularJs).

          scope.onClick = function() {
            input[0].value = "";

HTML5 placeholder css padding

If you want move placeholder text right and leave the cursor on the blank space you need to add space(s) at the start of the placeholder attribute:

<input type="email" placeholder="  Your email" />

Origin is not allowed by Access-Control-Allow-Origin

If you get this in Angular.js, then make sure you escape your port number like this:

var Project = $resource(
    'http://localhost\\:5648/api/...', {'a':'b'}, {
        update: { method: 'PUT' }

See here for more info on it.

What is your single most favorite command-line trick using Bash?

On Mac OS X,


will cycle through recent arguments in place. That's: press and release ESC, then press and release . (period key). On Ubuntu, I think it's ALT+..

You can do that more than once, to go back through all your recent arguments. It's kind of like CTRL + R, but for arguments only. It's also much safer than !! or $!, since you see what you're going to get before you actually run the command.

JPA Hibernate Persistence exception [PersistenceUnit: default] Unable to build Hibernate SessionFactory

I was getting this error even when all the relevant dependencies were in place because I hadn't created the schema in MySQL.

I thought it would be created automatically but it wasn't. Although the table itself will be created, you have to create the schema.

How to detect internet speed in JavaScript?

Well, this is 2017 so you now have Network Information API (albeit with a limited support across browsers as of now) to get some sort of estimate downlink speed information:


This is effective bandwidth estimate in Mbits per sec. The browser makes this estimate from recently observed application layer throughput across recently active connections. Needless to say, the biggest advantage of this approach is that you need not download any content just for bandwidth/ speed calculation.

You can look at this and a couple of other related attributes here

Due to it's limited support and different implementations across browsers (as of Nov 2017), would strongly recommend read this in detail

Loading all images using imread from a given folder

To add onto the answer from Rishabh and make it able to handle files that are not images that are found in the folder.

import matplotlib.image as mpimg

images = []
folder = './your/folder/'
for filename in os.listdir(folder):
        img = mpimg.imread(os.path.join(folder, filename))
        if img is not None:
        print('Cant import ' + filename)
images = np.asarray(images)

How do I create a comma delimited string from an ArrayList?

Something like:

String.Join(",", myArrayList.toArray(string.GetType()) );

Which basically loops ya know...


how about:

string.Join(",", Array.ConvertAll<object, string>(a.ToArray(), Convert.ToString));

How to change the font size on a matplotlib plot

This is an extension to Marius Retegan answer. You can make a separate JSON file with all your modifications and than load it with rcParams.update. The changes will only apply to the current script. So

import json
from matplotlib import pyplot as plt, rcParams

s = json.load(open("example_file.json")

and save this 'example_file.json' in the same folder.

  "lines.linewidth": 2.0,
  "axes.edgecolor": "#bcbcbc",
  "patch.linewidth": 0.5,
  "legend.fancybox": true,
  "axes.color_cycle": [
  "axes.facecolor": "#eeeeee",
  "axes.labelsize": "large",
  "axes.grid": true,
  "patch.edgecolor": "#eeeeee",
  "axes.titlesize": "x-large",
  "svg.fonttype": "path",
  "": ""

Difference between AutoPostBack=True and AutoPostBack=False?

There is one event which is default associate with any webcontrol. For example, in case of Button click event, in case of Check box CheckChangedEvent is there. So in case of AutoPostBack true these events are called by default and event handle at server side.

Access denied for user 'root'@'localhost' (using password: Yes) after password reset LINUX

On mac os, please follow below steps:

Stop MySQL

$ sudo /usr/local/mysql/support-files/mysql.server stop Start it in safe mode:

$ sudo mysqld_safe --skip-grant-tables (above line is the whole command)

This will be an ongoing command until the process is finished so open another shell/terminal window, log in without a password:

$ mysql -u root

mysql> UPDATE mysql.user SET Password=PASSWORD('password') WHERE User='root'; Start MySQL

sudo /usr/local/mysql/support-files/mysql.server start your new password is 'password'.

How to find a hash key containing a matching value

You could use hashname.key(valuename)

Or, an inversion may be in order. new_hash = hashname.invert will give you a new_hash that lets you do things more traditionally.

Why is an OPTIONS request sent and can I disable it?

I have solved this problem like.

if($_SERVER['REQUEST_METHOD'] == 'OPTIONS' && ENV == 'devel') {
    header('Access-Control-Allow-Origin: *');
    header('Access-Control-Allow-Headers: X-Requested-With');
    header("HTTP/1.1 200 OK");

It is only for development. With this I am waiting 9ms and 500ms and not 8s and 500ms. I can do that because production JS app will be on the same machine as production so there will be no OPTIONS but development is my local.

Maven 3 and JUnit 4 compilation problem: package org.junit does not exist

By default , maven looks at these folders for java and test classes respectively - src/main/java and src/test/java

When the src is specified with the test classes under source and the scope for junit dependency in pom.xml is mentioned as test - org.unit will not be found by maven.

Difference between JSONObject and JSONArray

When a JSON start's with {} it is a ObjectJSON object and when it start's with [] it is an Array JOSN Array

An JSON array can consist of a/many objects and that is called an array of objects

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

On Windows 10 install Python from Once installed add these two paths to PATH env variable C:\Users<your user>\AppData\Local\Programs\Python\Python38 C:\Users<your user>\AppData\Local\Programs\Python\Python38\Scripts

Open command prompt and following command should be working python --version pip --version

SonarQube Exclude a directory

Try something like this:


How can I delete Docker's images?

I found the answer in this command:

docker images --no-trunc | grep none | awk '{print $3}' | xargs docker rmi

I had your problem when I deleted some images that were being used, and I didn't realise (using docker ps -a).

How can I find the version of php that is running on a distinct domain name?

You can’t. One reason is that not every web site uses PHP. And another reason is: Even if there are some signs that PHP might be used (e.g. .php file name extension, some “PHPSESSID” parameter, X-Powered-By header field containing “PHP”, etc.) those information might be spoofed to let you think PHP is used.

How can I get key's value from dictionary in Swift?

Use subscripting to access the value for a dictionary key. This will return an Optional:

let apple: String? = companies["AAPL"]


if let apple = companies["AAPL"] {
    // ...

You can also enumerate over all of the keys and values:

var companies = ["AAPL" : "Apple Inc", "GOOG" : "Google Inc", "AMZN" : ", Inc", "FB" : "Facebook Inc"]

for (key, value) in companies {
    print("\(key) -> \(value)")

Or enumerate over all of the values:

for value in Array(companies.values) {

How to convert int to Integer

int iInt = 10;
Integer iInteger = new Integer(iInt);

C++11 introduced a standardized memory model. What does it mean? And how is it going to affect C++ programming?

The above answers get at the most fundamental aspects of the C++ memory model. In practice, most uses of std::atomic<> "just work", at least until the programmer over-optimizes (e.g., by trying to relax too many things).

There is one place where mistakes are still common: sequence locks. There is an excellent and easy-to-read discussion of the challenges at Sequence locks are appealing because the reader avoids writing to the lock word. The following code is based on Figure 1 of the above technical report, and it highlights the challenges when implementing sequence locks in C++:

atomic<uint64_t> seq; // seqlock representation
int data1, data2;     // this data will be protected by seq

T reader() {
    int r1, r2;
    unsigned seq0, seq1;
    while (true) {
        seq0 = seq;
        r1 = data1; // INCORRECT! Data Race!
        r2 = data2; // INCORRECT!
        seq1 = seq;

        // if the lock didn't change while I was reading, and
        // the lock wasn't held while I was reading, then my
        // reads should be valid
        if (seq0 == seq1 && !(seq0 & 1))
    use(r1, r2);

void writer(int new_data1, int new_data2) {
    unsigned seq0 = seq;
    while (true) {
        if ((!(seq0 & 1)) && seq.compare_exchange_weak(seq0, seq0 + 1))
            break; // atomically moving the lock from even to odd is an acquire
    data1 = new_data1;
    data2 = new_data2;
    seq = seq0 + 2; // release the lock by increasing its value to even

As unintuitive as it seams at first, data1 and data2 need to be atomic<>. If they are not atomic, then they could be read (in reader()) at the exact same time as they are written (in writer()). According to the C++ memory model, this is a race even if reader() never actually uses the data. In addition, if they are not atomic, then the compiler can cache the first read of each value in a register. Obviously you wouldn't want that... you want to re-read in each iteration of the while loop in reader().

It is also not sufficient to make them atomic<> and access them with memory_order_relaxed. The reason for this is that the reads of seq (in reader()) only have acquire semantics. In simple terms, if X and Y are memory accesses, X precedes Y, X is not an acquire or release, and Y is an acquire, then the compiler can reorder Y before X. If Y was the second read of seq, and X was a read of data, such a reordering would break the lock implementation.

The paper gives a few solutions. The one with the best performance today is probably the one that uses an atomic_thread_fence with memory_order_relaxed before the second read of the seqlock. In the paper, it's Figure 6. I'm not reproducing the code here, because anyone who has read this far really ought to read the paper. It is more precise and complete than this post.

The last issue is that it might be unnatural to make the data variables atomic. If you can't in your code, then you need to be very careful, because casting from non-atomic to atomic is only legal for primitive types. C++20 is supposed to add atomic_ref<>, which will make this problem easier to resolve.

To summarize: even if you think you understand the C++ memory model, you should be very careful before rolling your own sequence locks.

Center content vertically on Vuetify

<v-container> has to be right after <template>, if there is a <div> in between, the vertical align will just not work.

  <v-container fill-height>
      <v-row class="justify-center align-center">
        <v-col cols="12" sm="4">
            Centered both vertically and horizontally

rebase in progress. Cannot commit. How to proceed or stop (abort)?

I got into this state recently. After resolving conflicts during a rebase, I committed my changes, rather than running git rebase --continue. This yields the same messages you saw when you ran your git status and git rebase --continue commands. I resolved the issue by running git rebase --abort, and then re-running the rebase. One could likely also skip the rebase, but I wasn't sure what state that would leave me in.

$ git rebase --continue
Applying: <commit message>
No changes - did you forget to use 'git add'?
If there is nothing left to stage, chances are that something else
already introduced the same changes; you might want to skip this patch.

When you have resolved this problem, run "git rebase --continue".
If you prefer to skip this patch, run "git rebase --skip" instead.
To check out the original branch and stop rebasing, run "git rebase --abort".

$ git status
rebase in progress; onto 4df0775
You are currently rebasing branch '<local-branch-name>' on '4df0775'.
  (all conflicts fixed: run "git rebase --continue")

nothing to commit, working directory clean

Reverse Contents in Array

my approach is swapping the first and last element of the array

int i,j;
for ( i = 0,j = size - 1 ; i < j ; i++,j--)
    int temp = A[i];
    A[i] = A[j];
    A[j] = temp; 

How to import set of icons into Android Studio project

Newer versions of Android support vector graphics, which is preferred over PNG icons. Android Studio 2.1.2 (and probably earlier versions) comes with Vector Asset Studio, which will automatically create PNG files for vector graphics that you add.

The Vector Asset Studio supports importing vector icons from the SDK, as well as your own SVG files.

This article describes Vector Asset Studio:

Summary for how to add a vector graphic with PNG files (partially copied from that URL):

  1. In the Project window, select the Android view.
  2. Right-click the res folder and select New > Vector Asset.
  3. The Material Icon radio button should be selected; then click Choose
  4. Select your icon, tweak any settings you need to tweak, and Finish.
  5. Depending on your settings (see article), PNGs are generated during build at the app/build/generated/res/pngs/debug/ folder.

How to add to the end of lines containing a pattern with sed or awk?

You can append the text to $0 in awk if it matches the condition:

awk '/^all:/ {$0=$0" anotherthing"} 1' file


  • /patt/ {...} if the line matches the pattern given by patt, then perform the actions described within {}.
  • In this case: /^all:/ {$0=$0" anotherthing"} if the line starts (represented by ^) with all:, then append anotherthing to the line.
  • 1 as a true condition, triggers the default action of awk: print the current line (print $0). This will happen always, so it will either print the original line or the modified one.


For your given input it returns:

all: thing otherthing anotherthing
some other stuff

Note you could also provide the text to append in a variable:

$ awk -v mytext=" EXTRA TEXT" '/^all:/ {$0=$0mytext} 1' file
all: thing otherthing EXTRA TEXT
some other stuff

convert xml to java object using jaxb (unmarshal)


On the Tests class we will add an @XmlRootElement annotation. Doing this will let your JAXB implementation know that when a document starts with this element that it should instantiate this class. JAXB is configuration by exception, this means you only need to add annotations where your mapping differs from the default. Since the testData property differs from the default mapping we will use the @XmlElement annotation. You may find the following tutorial helpful:

package forum11221136;

import javax.xml.bind.annotation.*;

public class Tests {

    TestData testData;

    public TestData getTestData() {
        return testData;

    public void setTestData(TestData testData) {
        this.testData = testData;



On this class I used the @XmlType annotation to specify the order in which the elements should be ordered in. I added a testData property that appeared to be missing. I also used an @XmlElement annotation for the same reason as in the Tests class.

package forum11221136;

import java.util.List;
import javax.xml.bind.annotation.*;

@XmlType(propOrder={"title", "book", "count", "testData"})
public class TestData {
    String title;
    String book;
    String count;
    List<TestData> testData;

    public String getTitle() {
        return title;
    public void setTitle(String title) {
        this.title = title;
    public String getBook() {
        return book;
    public void setBook(String book) { = book;
    public String getCount() {
        return count;
    public void setCount(String count) {
        this.count = count;
    public List<TestData> getTestData() {
        return testData;
    public void setTestData(List<TestData> testData) {
        this.testData = testData;


Below is an example of how to use the JAXB APIs to read (unmarshal) the XML and populate your domain model and then write (marshal) the result back to XML.

package forum11221136;

import javax.xml.bind.*;

public class Demo {

    public static void main(String[] args) throws Exception {
        JAXBContext jc = JAXBContext.newInstance(Tests.class);

        Unmarshaller unmarshaller = jc.createUnmarshaller();
        File xml = new File("src/forum11221136/input.xml");
        Tests tests = (Tests) unmarshaller.unmarshal(xml);

        Marshaller marshaller = jc.createMarshaller();
        marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
        marshaller.marshal(tests, System.out);


Sequence contains more than one element

Use FirstOrDefault insted of SingleOrDefault..

SingleOrDefault returns a SINGLE element or null if no element is found. If 2 elements are found in your Enumerable then it throws the exception you are seeing

FirstOrDefault returns the FIRST element it finds or null if no element is found. so if there are 2 elements that match your predicate the second one is ignored

   public int GetPackage(int id,int emp)
             int getpackages=Convert.ToInt32(EmployerSubscriptionPackage.GetAllData().Where(x
   => x.SubscriptionPackageID ==`enter code here` id && x.EmployerID==emp ).FirstOrDefault().ID);
               return getpackages;

 1. var EmployerId = Convert.ToInt32(Session["EmployerId"]);
               var getpackage = GetPackage(employerSubscription.ID, EmployerId);

Why is super.super.method(); not allowed in Java?

public class SubSubClass extends SubClass {

    public void print() {

    public static void main(String[] args) {
        new SubSubClass().print();

class SuperClass {

    public void print() {
        System.out.println("Printed in the GrandDad");

class SubClass extends SuperClass {

    public void superPrint() {

Output: Printed in the GrandDad

How to unescape HTML character entities in Java?

The most reliable way is with

String cleanedString = StringEscapeUtils.unescapeHtml4(originalString);

from org.apache.commons.lang3.StringEscapeUtils.

And to escape the whitespaces

cleanedString = cleanedString.trim();

This will ensure that whitespaces due to copy and paste in web forms to not get persisted in DB.

Android Webview - Webpage should fit the device screen

Making Changes to the answer by danh32 since the display.getWidth(); is now deprecated.

private int getScale(){
    Point p = new Point();
    Display display = ((WindowManager) getSystemService(Context.WINDOW_SERVICE)).getDefaultDisplay(); 
    int width = p.x; 
    Double val = new Double(width)/new Double(PIC_WIDTH);
    val = val * 100d;
    return val.intValue();

Then use

WebView web = new WebView(this);
web.setPadding(0, 0, 0, 0);

How to calculate the angle between a line and the horizontal axis?

Based on reference "Peter O".. Here is the java version

private static final float angleBetweenPoints(PointF a, PointF b) {
float deltaY = b.y - a.y;
float deltaX = b.x - a.x;
return (float) (Math.atan2(deltaY, deltaX)); }

How to use DISTINCT and ORDER BY in same SELECT statement?

Just use this code, If you want values of [Category] and [CreationDate] columns

SELECT [Category], MAX([CreationDate]) FROM [MonitoringJob] 
             GROUP BY [Category] ORDER BY MAX([CreationDate]) DESC

Or use this code, If you want only values of [Category] column.

SELECT [Category] FROM [MonitoringJob] 
GROUP BY [Category] ORDER BY MAX([CreationDate]) DESC

You'll have all the distinct records what ever you want.

How to check if a file exists from a url

Hi according to our test between 2 different servers the results are as follows:

using curl for checking 10 .png files (each about 5 mb) was on average 5.7 secs. using header check for the same thing took average of 7.8 seconds!

So in our test curl was much faster if you have to check larger files!

our curl function is:

function remote_file_exists($url){
    $ch = curl_init($url);
    curl_setopt($ch, CURLOPT_NOBODY, true);
    $httpCode = curl_getinfo($ch, CURLINFO_HTTP_CODE);
    if( $httpCode == 200 ){return true;}
    return false;

here is our header check sample:

function UR_exists($url){
   return stripos($headers[0],"200 OK")?true:false;

How to reset the bootstrap modal when it gets closed and open it fresh again?

Tried it and working well

$('#MyModal').on('', function () {

reset is dom build-in funtion, you can also use $(this).find('form')[0].reset();

And Bootstrap's modal class exposes a few events for hooking into modal functionality, detail at here. This event is fired immediately when the hide instance method has been called. This event is fired when the modal has finished being hidden from the user (will wait for CSS transitions to complete).

Order of execution of tests in TestNG

Use this:

public class TestNG
        public void setUp() 
                   /*--Initialize broowsers--*/


        public void Login() 


        public void Logout() 


        public void tearDown() 
                //--Close driver--//



Usually TestNG provides number of annotations, We can use @BeforeSuite, @BeforeTest, @BeforeClass for initializing browsers/setup.

We can assign priority if you have written number of test cases in your script and want to execute as per assigned priority then use: @Test(priority=0) starting from 0,1,2,3....

Meanwhile we can group number of test cases and execute it by grouping. for that we will use @Test(Groups='Regression')

At the end like closing the browsers we can use @AfterTest, @AfterSuite, @AfterClass annotations.

Finding the id of a parent div using Jquery


Bootstrap row class contains margin-left and margin-right which creates problems

Old topic, but I was recently affected by this.

Using a class "row-fluid" instead of "row" worked fine for me but I'm not sure if it's fully supported going forward.

So after reading Why does the bootstrap .row has a default margin-left of -30px I just used the <div> (without any row class) and it behaved exactly like <div class="row-fluid">

Passing parameter to controller from route in laravel

    $ php artisan route:list
  +--------+--------------------------------+----------------------------+--    -----------------+----------------------------------------------------+---------  ---+
  | Domain | Method                         | URI                        |  Name              | Action                                             |    Middleware |
  |        | GET|HEAD                       | /                          |                           
  |        | GET                            | campaign/showtakeup/{id}   | showtakeup         | App\Http\Controllers\campaignController@showtakeup | auth       |     |


  Route::get('campaign/showtakeup/{id}', ['uses' =>'campaignController@showtakeup'])->name('showtakeup');


 @foreach($campaign as $campaigns)

   //route parameters; you may pass them as the second argument to the method:

   <a href="{{route('showtakeup', ['id' => $campaigns->id])}}">{{ $campaigns->name }}</a>


Hope this solves your problem. Thanks

Creating a UITableView Programmatically

#import "ViewController.h"

@interface ViewController ()


    NSMutableArray *name;



- (void)viewDidLoad 


    [super viewDidLoad];
    name=[[NSMutableArray alloc]init];
    [name addObject:@"ronak"];
    [name addObject:@"vibha"];
    [name addObject:@"shivani"];
    [name addObject:@"nidhi"];
    [name addObject:@"firdosh"];
    [name addObject:@"himani"];

    _tableview_outlet.delegate = self;
    _tableview_outlet.dataSource = self;


- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section


return [name count];


- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath


    static NSString *simpleTableIdentifier = @"cell";

    UITableViewCell *cell = [tableView       dequeueReusableCellWithIdentifier:simpleTableIdentifier];

    if (cell == nil) {
        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:simpleTableIdentifier];

    cell.textLabel.text = [name objectAtIndex:indexPath.row];
    return cell;

Correct way to remove plugin from Eclipse

I'm using Eclipse Kepler release. There is no Installation Details or About Eclipse menu item under help. For me, it was Help | Eclipse Marketplace...

I had to click on the "Installed" tab. The plug-in I wanted to remove was listed there, with an "Uninstall" option.

File Upload with Angular Material

with Angular material

<div (click)="">
   <button mat-raised-button color="primary">Choose File</button>
   <input #uploadFile (change)="upload($event)" type='file' style="display:none"/> 




Notepad++ incrementally replace

i had the same problem with more than 250 lines and here is how i did it:

for example :

<row id="1" />
<row id="1" />
<row id="1" />
<row id="1" />
<row id="1" />

you put the cursor just after the "1" and you click on alt + shift and start descending with down arrow until your reach the bottom line now you see a group of selections click on erase to erase the number 1 on each line simultaneously and go to Edit -> Column Editor and select Number to Insert then put 1 in initial number field and 1 in incremented by field and check zero numbers and click ok

Congratulations you did it :)

Xcode 4 - "Valid signing identity not found" error on provisioning profiles on a new Macintosh install

I had the same thing happen to me as Tiguero (thank you for your answer, it gave me hope), but here is a way to get rid of the "valid signing identity not found" error without having to delete all your provisioning profiles.

If you are on a new system and cannot retrieve your keys from another system, you do indeed have to delete and regenerate new Development and Distribution certificates for Xcode. You can do this via Xcode, or the old-fashioned way using Keychain Access.

Then what you can do is go into Provisioning, and in each tab, Development, and Distribution, click Edit next to the profile you want to update, and then Modify.

You will see a list of certificates, and you must check off the box next to the one you just made, then Submit.

Once you do this, go into your Xcode (I'm using 4.3.3) Organizer > Devices > Library > Provisioning Profiles where you are getting the error message, and click Refresh. Once you answer the prompt to enter your developer login, Organizer will re-download the profiles, and the error message should go away.

Forwarding port 80 to 8080 using NGINX

You can define an upstream and use it in proxy_pass

server {  
   listen        8082;

   location ~ /(.*) {  
       proxy_pass  test_server;  
       proxy_set_header Host $host;  
       proxy_set_header X-Real-IP $remote_addr;  
       proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;  
       proxy_set_header X-Forwarded-Proto $scheme;  
       proxy_redirect    off;  


  upstream test_server  
         server test-server:8989  

How can I toggle word wrap in Visual Studio?

As of Visual Studio 2013, the word wrap feature is finally usable—it respects indentation. There's still a couple of issues (line highlighting, selection), but it's worth using. Here's how

enter image description here

How to choose multiple files using File Upload Control?

To add multiple files use below code

<html xmlns="">
<head runat="server">
    <style type="text/css">
    <form id="form1" runat="server">
    <div id="fileUploadarea"><asp:FileUpload ID="fuPuzzleImage" runat="server" CssClass="fileUpload" /><br /></div><br />
    <div><input style="display:block;" id="btnAddMoreFiles" type="button" value="Add more images" onclick="AddMoreImages();" /><br />
        <asp:Button ID="Button1" runat="server" onclick="Button1_Click" Text="Upload" />
    <script language="javascript" type="text/javascript">
        function AddMoreImages() {
            if (!document.getElementById && !document.createElement)
                return false;
            var fileUploadarea = document.getElementById("fileUploadarea");
            if (!fileUploadarea)
                return false;
            var newLine = document.createElement("br");
            var newFile = document.createElement("input");
            newFile.type = "file";
            newFile.setAttribute("class", "fileUpload");

            if (!AddMoreImages.lastAssignedId)
                AddMoreImages.lastAssignedId = 100;
            newFile.setAttribute("id", "FileUpload" + AddMoreImages.lastAssignedId);
            newFile.setAttribute("name", "FileUpload" + AddMoreImages.lastAssignedId);
            var div = document.createElement("div");
            div.setAttribute("id", "div" + AddMoreImages.lastAssignedId);


Server side code:

    HttpFileCollection hfc = Request.Files;
    for (int i = 0; i < hfc.Count; i++)
        HttpPostedFile hpf = hfc[i];
        if (hpf.ContentLength > 0)
            hpf.SaveAs(Server.MapPath("~/uploads/") +System.IO.Path.GetFileName(hpf.FileName);                        
catch (Exception)

Online code beautifier and formatter

JsonLint is good for validating and formatting JSON.

Error: 0xC0202009 at Data Flow Task, OLE DB Destination [43]: SSIS Error Code DTS_E_OLEDBERROR. An OLE DB error has occurred. Error code: 0x80040E21

This is usually caused by truncation (the incoming value is too large to fit in the destination column). Unfortunately SSIS will not tell you the name of the offending column. I use a third-party component to get this information:

Polymorphism: Why use "List list = new ArrayList" instead of "ArrayList list = new ArrayList"?

This is also helpful when exposing a public interface. If you have a method like this,

public ArrayList getList();

Then you decide to change it to,

public LinkedList getList();

Anyone who was doing ArrayList list = yourClass.getList() will need to change their code. On the other hand, if you do,

public List getList();

Changing the implementation doesn't change anything for the users of your API.

Automatically resize images with browser size using CSS

image container

Scaling images using the above trick only works if the container the images are in changes size.

The #icons container uses px values for the width and height. px values don't scale when the browser is resized.


Use one of the following approaches:

  1. Define the width and/or height using % values.
  2. Use a series of @media queries to set the width and height to different values based on the current screen size.

How to fix "could not find a base address that matches schema http"... in WCF

The solution is to define a custom binding inside your Web.Config file and set the security mode to "Transport". Then you just need to use the bindingConfiguration property inside your endpoint definition to point to your custom binding.

See here: Scott's Blog: WCF Bindings Needed For HTTPS

How do I change selected value of select2 dropdown with JqGrid?

if you want to select a single value then use $('#select').val(1).change()

if you want to select multiple values then set value in array so you can use this code $('#select').val([1,2,3]).change()

Prevent typing non-numeric in input type number

Please note that e.which, e.keyCode and e.charCode are deprecated:

I prefer e.key:

document.querySelector("input").addEventListener("keypress", function (e) {
    var allowedChars = '0123456789.';
    function contains(stringValue, charValue) {
        return stringValue.indexOf(charValue) > -1;
    var invalidKey = e.key.length === 1 && !contains(allowedChars, e.key)
            || e.key === '.' && contains(, '.');
    invalidKey && e.preventDefault();});

This function doesn't interfere with control codes in Firefox (Backspace, Tab, etc) by checking the string length: e.key.length === 1.

It also prevents duplicate dots at the beginning and between the digits: e.key === '.' && contains(, '.')

Unfortunately, it doesn't prevent multiple dots at the end: 234....

It seems there is no way to cope with it.

How do I correctly upgrade angular 2 (npm) to the latest version?

Upgrade to latest Angular 5

Angular Dep packages: npm install @angular/{animations,common,compiler,core,forms,http,platform-browser,platform-browser-dynamic,router}@latest --save

Other packages that are installed by the angular cli npm install --save core-js@latest rxjs@latest zone.js@latest

Angular Dev packages: npm install --save-dev @angular/{compiler-cli,cli,language-service}@latest

Types Dev packages: npm install --save-dev @types/{jasmine,jasminewd2,node}@latest

Other packages that are installed as dev dev by the angular cli: npm install --save-dev codelyzer@latest jasmine-core@latest jasmine-spec-reporter@latest karma@latest karma-chrome-launcher@latest karma-cli@latest karma-coverage-istanbul-reporter@latest karma-jasmine@latest karma-jasmine-html-reporter@latest protractor@latest ts-node@latest tslint@latest

Install the latest supported version used by the Angular cli (don't do @latest): npm install --save-dev [email protected]

Rename file angular-cli.json to .angular-cli.json and update the content:

  "$schema": "./node_modules/@angular/cli/lib/config/schema.json",
  "project": {
    "name": "project3-example"
  "apps": [
      "root": "src",
      "outDir": "dist",
      "assets": [
      "index": "index.html",
      "main": "main.ts",
      "polyfills": "polyfills.ts",
      "test": "test.ts",
      "tsconfig": "",
      "testTsconfig": "tsconfig.spec.json",
      "prefix": "app",
      "styles": [
      "scripts": [],
      "environmentSource": "environments/environment.ts",
      "environments": {
        "dev": "environments/environment.ts",
        "prod": "environments/"
  "e2e": {
    "protractor": {
      "config": "./protractor.conf.js"
  "lint": [
      "project": "src/",
      "exclude": "**/node_modules/**"
      "project": "src/tsconfig.spec.json",
      "exclude": "**/node_modules/**"
      "project": "e2e/tsconfig.e2e.json",
      "exclude": "**/node_modules/**"
  "test": {
    "karma": {
      "config": "./karma.conf.js"
  "defaults": {
    "styleExt": "css",
    "component": {}

Remove Trailing Spaces and Update in Columns in SQL Server

To remove Enter:

Update [table_name] set

To remove Tab:

Update [table_name] set

Java - Reading XML file

Reading xml the easy way:

package com.mkyong.core;

import javax.xml.bind.annotation.XmlAttribute;
import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlRootElement;

public class Customer {

    String name;
    int age;
    int id;

    public String getName() {
        return name;

    public void setName(String name) { = name;

    public int getAge() {
        return age;

    public void setAge(int age) {
        this.age = age;

    public int getId() {
        return id;

    public void setId(int id) { = id;



package com.mkyong.core;

import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Marshaller;

public class JAXBExample {
    public static void main(String[] args) {

      Customer customer = new Customer();

      try {

        File file = new File("C:\\file.xml");
        JAXBContext jaxbContext = JAXBContext.newInstance(Customer.class);
        Marshaller jaxbMarshaller = jaxbContext.createMarshaller();

        // output pretty printed
        jaxbMarshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);

        jaxbMarshaller.marshal(customer, file);
        jaxbMarshaller.marshal(customer, System.out);

          } catch (JAXBException e) {


How can a Jenkins user authentication details be "passed" to a script which uses Jenkins API to create jobs?

  • With Jenkins CLI you do not have to reload everything - you just can load the job (update-job command). You can't use tokens with CLI, AFAIK - you have to use password or password file.

  • Token name for user can be obtained via http://<jenkins-server>/user/<username>/configure - push on 'Show API token' button.

  • Here's a link on how to use API tokens (it uses wget, but curl is very similar).

Pythonic way to return list of every nth item in a larger list

>>> lst = list(range(165))
>>> lst[0::10]
[0, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160]

Note that this is around 100 times faster than looping and checking a modulus for each element:

$ python -m timeit -s "lst = list(range(1000))" "lst1 = [x for x in lst if x % 10 == 0]"
1000 loops, best of 3: 525 usec per loop
$ python -m timeit -s "lst = list(range(1000))" "lst1 = lst[0::10]"
100000 loops, best of 3: 4.02 usec per loop

Classes cannot be accessed from outside package

Note that the default when you make a class is not public as far as packages are considered. Make sure that you actually write public class [MyClass] { when defining your class. I've made this mistake more times than I care to admit.

How to recursively delete an entire directory with PowerShell 2.0?

There seems to be issues where Remove-Item -Force -Recurse can intermittently fail on Windows because the underlying filesystem is asynchronous. This answer seems to address it. The user has also been actively involved with the Powershell team on GitHub.

How to write to the Output window in Visual Studio?

#include <Windows.h>

wstring outputMe = L"can" + L" concatenate\n";

Android WebView not loading an HTTPS URL

Please visit this link:

Add this overriding method to your WebViewClient implementation. You'll need to compile it with Android SDK 2.2 (API level 8) or later. The method appears in the public SDK as of 2.2 (API level 8) but we've tested it on devices running 2.1, 1.6 and 1.5 and it works on those devices too (so obviously the behaviour has been there all along).

public void onReceivedSslError(WebView view, SslErrorHandler handler, SslError error) {
    handler.proceed(); // Ignore SSL certificate errors

this will help you.

How to randomly pick an element from an array

Java has a Random class in the java.util package. Using it you can do the following:

Random rnd = new Random();
int randomNumberFromArray = array[rnd.nextInt(3)];

Hope this helps!

JSON serialization/deserialization in ASP.Net Core

You can use Newtonsoft.Json, it's a dependency of Microsoft.AspNet.Mvc.ModelBinding which is a dependency of Microsoft.AspNet.Mvc. So, you don't need to add a dependency in your project.json.

#using Newtonsoft.Json

Note, using a WebAPI controller you don't need to deal with JSON.

UPDATE ASP.Net Core 3.0

Json.NET has been removed from the ASP.NET Core 3.0 shared framework.

You can use the new JSON serializer layers on top of the high-performance Utf8JsonReader and Utf8JsonWriter. It deserializes objects from JSON and serializes objects to JSON. Memory allocations are kept minimal and includes support for reading and writing JSON with Stream asynchronously.

To get started, use the JsonSerializer class in the System.Text.Json.Serialization namespace. See the documentation for information and samples.

To use Json.NET in an ASP.NET Core 3.0 project:


Read Json.NET support in Migrate from ASP.NET Core 2.2 to 3.0 Preview 2 for more information.

Setting a property by reflection with a string value

If you are writing Metro app, you should use other code:

Ship ship = new Ship();
string value = "5.5";
PropertyInfo propertyInfo = ship.GetType().GetTypeInfo().GetDeclaredProperty("Latitude");
propertyInfo.SetValue(ship, Convert.ChangeType(value, propertyInfo.PropertyType));



instead of


Get all rows from SQLite

Cursor cursor = myDb.viewData();

        if (cursor.moveToFirst()){
              do {
                 String itemname=cursor.getString(cursor.getColumnIndex(myDb.col_2));
                 String price=cursor.getString(cursor.getColumnIndex(myDb.col_3));
                 String quantity=cursor.getString(cursor.getColumnIndex(myDb.col_4));
                 String table_no=cursor.getString(cursor.getColumnIndex(myDb.col_5));

                 }while (cursor.moveToNext());



Read CSV with Scanner()


This should work.

import java.util.Scanner;

public class TestScanner {

    public static void main(String[] args) throws FileNotFoundException {
        Scanner scanner = new Scanner(new File("/Users/pankaj/abc.csv"));


For CSV File:

a,b,c d,e
1,2,3 4,5

Output is:

a|b|c d|e
1|2|3 4|5
X|Y|Z A|B|

Close a MessageBox after several seconds

There is an codeproject project avaliable HERE that provides this functuanility.

Following many threads here on SO and other boards this cant be done with the normal MessageBox.


I have an idea that is a bit ehmmm yeah..

Use a timer and start in when the MessageBox appears. If your MessageBox only listens to the OK Button (only 1 possibility) then use the OnTick-Event to emulate an ESC-Press with SendKeys.Send("{ESC}"); and then stop the timer.

How to map to multiple elements with Java 8 streams?

It's an interesting question, because it shows that there are a lot of different approaches to achieve the same result. Below I show three different implementations.

Default methods in Collection Framework: Java 8 added some methods to the collections classes, that are not directly related to the Stream API. Using these methods, you can significantly simplify the implementation of the non-stream implementation:

Collection<DataSet> convert(List<MultiDataPoint> multiDataPoints) {
    Map<String, DataSet> result = new HashMap<>();
    multiDataPoints.forEach(pt ->
        pt.keyToData.forEach((key, value) ->
                key, k -> new DataSet(k, new ArrayList<>()))
            .dataPoints.add(new DataPoint(pt.timestamp, value))));
    return result.values();

Stream API with flatten and intermediate data structure: The following implementation is almost identical to the solution provided by Stuart Marks. In contrast to his solution, the following implementation uses an anonymous inner class as intermediate data structure.

Collection<DataSet> convert(List<MultiDataPoint> multiDataPoints) {
        .flatMap(mdp -> mdp.keyToData.entrySet().stream().map(e ->
            new Object() {
                String key = e.getKey();
                DataPoint dataPoint = new DataPoint(mdp.timestamp, e.getValue());
                groupingBy(t -> t.key, mapping(t -> t.dataPoint, toList())),
                m -> m.entrySet().stream().map(e -> new DataSet(e.getKey(), e.getValue())).collect(toList())));

Stream API with map merging: Instead of flattening the original data structures, you can also create a Map for each MultiDataPoint, and then merge all maps into a single map with a reduce operation. The code is a bit simpler than the above solution:

Collection<DataSet> convert(List<MultiDataPoint> multiDataPoints) {
        .map(mdp -> mdp.keyToData.entrySet().stream()
            .collect(toMap(e -> e.getKey(), e -> asList(new DataPoint(mdp.timestamp, e.getValue())))))
        .reduce(new HashMap<>(), mapMerger())
        .map(e -> new DataSet(e.getKey(), e.getValue()))

You can find an implementation of the map merger within the Collectors class. Unfortunately, it is a bit tricky to access it from the outside. Following is an alternative implementation of the map merger:

<K, V> BinaryOperator<Map<K, List<V>>> mapMerger() {
    return (lhs, rhs) -> {
        Map<K, List<V>> result = new HashMap<>();
        lhs.forEach((key, value) -> result.computeIfAbsent(key, k -> new ArrayList<>()).addAll(value));
        rhs.forEach((key, value) -> result.computeIfAbsent(key, k -> new ArrayList<>()).addAll(value));
        return result;

How to escape a JSON string containing newline characters using JavaScript?

Take your JSON and .stringify() it. Then use the .replace() method and replace all occurrences of \n with \\n.


As far as I know of, there are no well-known JS libraries for escaping all special characters in a string. But, you could chain the .replace() method and replace all of the special characters like this:

var myJSONString = JSON.stringify(myJSON);
var myEscapedJSONString = myJSONString.replace(/\\n/g, "\\n")
                                      .replace(/\\'/g, "\\'")
                                      .replace(/\\"/g, '\\"')
                                      .replace(/\\&/g, "\\&")
                                      .replace(/\\r/g, "\\r")
                                      .replace(/\\t/g, "\\t")
                                      .replace(/\\b/g, "\\b")
                                      .replace(/\\f/g, "\\f");
// myEscapedJSONString is now ready to be POST'ed to the server. 

But that's pretty nasty, isn't it? Enter the beauty of functions, in that they allow you to break code into pieces and keep the main flow of your script clean, and free of 8 chained .replace() calls. So let's put that functionality into a function called, escapeSpecialChars(). Let's go ahead and attach it to the prototype chain of the String object, so we can call escapeSpecialChars() directly on String objects.

Like so:

String.prototype.escapeSpecialChars = function() {
    return this.replace(/\\n/g, "\\n")
               .replace(/\\'/g, "\\'")
               .replace(/\\"/g, '\\"')
               .replace(/\\&/g, "\\&")
               .replace(/\\r/g, "\\r")
               .replace(/\\t/g, "\\t")
               .replace(/\\b/g, "\\b")
               .replace(/\\f/g, "\\f");

Once we have defined that function, the main body of our code is as simple as this:

var myJSONString = JSON.stringify(myJSON);
var myEscapedJSONString = myJSONString.escapeSpecialChars();
// myEscapedJSONString is now ready to be POST'ed to the server

Rails params explained?

Basically, parameters are user specified data to rails application.

When you post a form, you do it generally with POST request as opposed to GET request. You can think normal rails requests as GET requests, when you browse the site, if it helps.

When you submit a form, the control is thrown back to the application. How do you get the values you have submitted to the form? params is how.

About your code. @vote = params[:vote] creates new Vote to database using data of params[:vote]. Given your form user submitted was named under name :vote, all data of it is in this :vote field of the hash.

Next two lines are used to get item and uid user has submitted to the form.

@extant = Vote.find(:last, :conditions => ["item_id = ? AND user_id = ?", item, uid])

finds newest, or last inserted, vote from database with conditions item_id = item and user_id = uid.

Next lines takes last vote time and current time.

How can I access Google Sheet spreadsheets only with Javascript?

For this type of thing you should use Google Fusion Tables. The API is designed for that purpose.

iOS9 getting error “an SSL error has occurred and a secure connection to the server cannot be made”

iOS 9 forces connections that are using HTTPS to be TLS 1.2 to avoid recent vulnerabilities. In iOS 8 even unencrypted HTTP connections were supported, so that older versions of TLS didn't make any problems either. As a workaround, you can add this code snippet to your Info.plist:


*referenced to App Transport Security (ATS)

enter image description here

How do I put a clear button inside my HTML text input box like the iPhone does?

It is so simple in HTML5

<input type="search">

This will do your job!

Array functions in jQuery

An easy way to get the max and min value in an array is as follows. This has been explained at get max & min values in array

var myarray = [5,8,2,4,11,7,3];
// Function to get the Max value in Array
Array.max = function( array ){
return Math.max.apply( Math, array );

// Function to get the Min value in Array
Array.min = function( array ){
return Math.min.apply( Math, array );
// Usage 

Entity Framework Provider type could not be loaded?

I had the same issue with Instantiating DBContext object from a unit test project. I checked my unit test project packages and I figured that EntityFramework package was not installed, I installed that from Nuget and problem solved (I think it's EF bug).

happy coding

How to get the index of a maximum element in a NumPy array along one axis

v = alli.max()
index = alli.argmax()
x, y = index/8, index%8

How to install Google Play Services in a Genymotion VM (with no drag and drop support)?

Tried to download Gapps app and install it on Genymotion, but realized that its already included within the emulator itself

how to get the last character of a string?

You can use this simple ES6 method

const lastChar = (str) => str.split('').reverse().join(',').replace(',', '')[str.length === str.length + 1 ? 1 : 0];_x000D_
// example_x000D_

This will work in every browsers.

Convert Int to String in Swift

let intAsString = 45.description     // "45"
let stringAsInt = Int("45")          // 45

Python multiprocessing PicklingError: Can't pickle <type 'function'>

When this problem comes up with multiprocessing a simple solution is to switch from Pool to ThreadPool. This can be done with no change of code other than the import-

from multiprocessing.pool import ThreadPool as Pool

This works because ThreadPool shares memory with the main thread, rather than creating a new process- this means that pickling is not required.

The downside to this method is that python isn't the greatest language with handling threads- it uses something called the Global Interpreter Lock to stay thread safe, which can slow down some use cases here. However, if you're primarily interacting with other systems (running HTTP commands, talking with a database, writing to filesystems) then your code is likely not bound by CPU and won't take much of a hit. In fact I've found when writing HTTP/HTTPS benchmarks that the threaded model used here has less overhead and delays, as the overhead from creating new processes is much higher than the overhead for creating new threads.

So if you're processing a ton of stuff in python userspace this might not be the best method.

How to round a number to n decimal places in Java

DecimalFormat is the best ways to output, but I don't prefer it. I always do this all the time, because it return the double value. So I can use it more than just output.




If you need large decimal places value, you can use BigDecimal instead. Anyways .0 is important. Without it the rounding of 0.33333d5 return 0.33333 and only 9 digits are allows. The second function without .0 has problems with 0.30000 return 0.30000000000000004.

Is the LIKE operator case-sensitive with MSSQL Server?

All this talk about collation seem a bit over-complicated. Why not just use something like:


Then your check is case insensitive whatever the collation

mysql extract year from date format

You can try this:


return SQL table as JSON in python

Most simple way,

use json.dumps but if its datetime will require to parse datetime into json serializer.

here is mine,

import MySQLdb, re, json
from datetime import date, datetime

def json_serial(obj):
    """JSON serializer for objects not serializable by default json code"""

    if isinstance(obj, (datetime, date)):
        return obj.isoformat()
    raise TypeError ("Type %s not serializable" % type(obj))

conn = MySQLdb.connect(instance)
curr = conn.cursor()
curr.execute("SELECT * FROM `assets`")
data = curr.fetchall()
print json.dumps(data, default=json_serial)

it will return json dump

one more simple method without json dumps, here get header and use zip to map with each finally made it as json but this is not change datetime into json serializer...

data_json = []
header = [i[0] for i in curr.description]
data = curr.fetchall()
for i in data:
    data_json.append(dict(zip(header, i)))
print data_json

Testing two JSON objects for equality ignoring child order in Java

For org.json I've rolled out my own solution, a method that compares to JSONObject instances. I didn't work with complex JSON objects in that project, so I don't know whether this works in all scenarios. Also, given that I use this in unit tests, I didn't put effort into optimizations. Here it is:

public static boolean jsonObjsAreEqual (JSONObject js1, JSONObject js2) throws JSONException {
    if (js1 == null || js2 == null) {
        return (js1 == js2);

    List<String> l1 =  Arrays.asList(JSONObject.getNames(js1));
    List<String> l2 =  Arrays.asList(JSONObject.getNames(js2));
    if (!l1.equals(l2)) {
        return false;
    for (String key : l1) {
        Object val1 = js1.get(key);
        Object val2 = js2.get(key);
        if (val1 instanceof JSONObject) {
            if (!(val2 instanceof JSONObject)) {
                return false;
            if (!jsonObjsAreEqual((JSONObject)val1, (JSONObject)val2)) {
                return false;

        if (val1 == null) {
            if (val2 != null) {
                return false;
        }  else if (!val1.equals(val2)) {
            return false;
    return true;

Check if a given key already exists in a dictionary and increment it

I prefer to do this in one line of code.

my_dict = {}

my_dict[some_key] = my_dict.get(some_key, 0) + 1

Dictionaries have a function, get, which takes two parameters - the key you want, and a default value if it doesn't exist. I prefer this method to defaultdict as you only want to handle the case where the key doesn't exist in this one line of code, not everywhere.

include external .js file in node.js app

This approach works for me in Node.js, Is there any problem with this one?

File 'include.js':

fs = require('fs');

File 'main.js':


fs.readFile('./file.json', function (err, data) {
    if (err) {
        console.log('ERROR: file.json not found...')
    } else {
        contents = JSON.parse(data)

How to pass a parameter to routerLink that is somewhere inside the URL?

Maybe it is really late answer but if you want to navigate another page with param you can,

[routerLink]="['/user',, 'details']"

also you shouldn't forget about routing config like ,

 [path: 'user/:id/details', component:userComponent, pathMatch: 'full']

Get the current time in C

Initialize your now variable.

time_t now = time(0); // Get the system time

The localtime function is used to convert the time value in the passed time_t to a struct tm, it doesn't actually retrieve the system time.

Calculate mean across dimension in a 2D array

If you do this a lot, NumPy is the way to go.

If for some reason you can't use NumPy:

>>> map(lambda x:sum(x)/float(len(x)), zip(*a))
[45.0, 10.5]

This Handler class should be static or leaks might occur: IncomingHandler

With the help of @Sogger's answer, I created a generic Handler:

public class MainThreadHandler<T extends MessageHandler> extends Handler {

    private final WeakReference<T> mInstance;

    public MainThreadHandler(T clazz) {
        // Remove the following line to use the current thread.
        mInstance = new WeakReference<>(clazz);

    public void handleMessage(Message msg) {
        T clazz = mInstance.get();
        if (clazz != null) {

The interface:

public interface MessageHandler {

    void handleMessage(Message msg);


I'm using it as follows. But I'm not 100% sure if this is leak-safe. Maybe someone could comment on this:

public class MyClass implements MessageHandler {

    private static final int DO_IT_MSG = 123;

    private MainThreadHandler<MyClass> mHandler = new MainThreadHandler<>(this);

    private void start() {
        // Do it in 5 seconds.
        mHandler.sendEmptyMessageDelayed(DO_IT_MSG, 5 * 1000);

    public void handleMessage(Message msg) {
        switch (msg.what) {
            case DO_IT_MSG:



Java: Insert multiple rows into MySQL with PreparedStatement

When MySQL driver is used you have to set connection param rewriteBatchedStatements to true ( jdbc:mysql://localhost:3306/TestDB?**rewriteBatchedStatements=true**).

With this param the statement is rewritten to bulk insert when table is locked only once and indexes are updated only once. So it is much faster.

Without this param only advantage is cleaner source code.

HTTP Error 404 when running Tomcat from Eclipse

If you changed the location, using option 'Use custom location (does not modify Tomcat installation)' and the deployed directory is "wtpwebapps" then you'll have to:

  1. Swtich Location from [workspace metadata] to /Servers/Tomcat v...., click Apply, OK.
  2. Retart server and if you find 404 error message than the server is working, it just doesn't have the startup file at the web-server location you have chosen. If you traverse to that location, you'll find a bunch of directories that was created. One of which is wtpwebapps, under which there is ROOT. This is your web-server's directory. You will need to go back to installed Tomcat directory and copy the content of <tomcat's installed dir>/web-apps/ROOT to your wtpwebapps. Restart the webserver and you should see the tomcat default page.
  3. For Server Status, Manager Apps and Host Manager to work, you'll have to copy other subdirectories from <tomcat's installed dir>/webapps (ie. docs, examples, host-manager, manager) to your "webapps" (NOT the wtpwebapps) directory.
  4. Edit the '<your web directory>/conf/tomcat-users.xml' and enter something like:
  5.       <role rolename="manager-gui"/>
          <role rolename="manager-status"/>
          <role rolename="manager-jmx"/>
          <role rolename="manager-script"/>
          <role rolename="admin-gui"/>
          <role rolename="admin"/>
          <user username="admin" password="yourpassword" roles="admin, admin-gui, manager-gui"/>
  6. Then edit the '<your web directory>/conf/server.xml', add the attribute:
    into the <Resource/> key of the <GlobalNamingResources/> group.
  7. Restart the server and try to login with the configured credentials.
NOTE: if you change the server configuration, say if you like to compare the default configuration (use tomcat installation directory) and the 'new directory', when switching back to the 'new directory' this 'tomcat-users.xml' will be overwritten by the default file, so SAVE THE CONTENT OF THIS FILE somewhere before doing that, then copy it back. If you only give the the username "admin" role, you will be prompted of help messages. It says: you should not grant the admin-gui, or manager-gui role the 'manager-jmx' and 'manager-script' roles.

Android global variable

I checked for similar answer, but those given here don't fit my needs. I find something that, from my point of view, is what you're looking for. The only possible black point is a security matter (or maybe not) since I don't know about security.

I suggest using Interface (no need to use Class with constructor and so...), since you only have to create something like :

public interface ActivityClass {

    public static final String MYSTRING_1 = "STRING";

    public static final int MYINT_1 = 1;


Then you can access everywhere within your classes by using the following:

int myInt = ActivityClass.MYINT_1;
String myString = ActivityClass.MYSTRING_1;

You should not use <Link> outside a <Router>

I was getting this error because I was importing a reusable component from an npm library and the versions of react-router-dom did not match.

So make sure you use the same version in both places!

Sometimes adding a WCF Service Reference generates an empty reference.cs

I've been bashing my head for a whole day with this exact problem. I've just fixed it. Here's how...

The service had to run over SSL (i.e. it's at

Adding a service reference to the WCF service on a development server worked just fine.

Deploying the exact same build of the WCF service on the live production server, then switching to the client application and configuring the service reference to point to the live service displayed no errors but the app wouldn't build: It turns out that the service reference's Reference.cs file was completely empty! Updating the service reference made no difference. Cleaning the solution didn't help. Restarting VS2010 made no difference. Creating a new blank solution, starting a console project and adding a service reference to the live service exhibited exactly the same problem.

I didn't think it was due to conflicting types or anything, but what the heck - I reconfigured the WCF service reference by unchecking "Reuse types in all referenced assemblies". No joy; I put the check mark back.

Next step was to try svcutil on the reference URL to see if that would help uncover the problem. Here's the command:

svcutil /t:code /d:D:\test

This produced the following:

Microsoft (R) Service Model Metadata Tool
[Microsoft (R) Windows (R) Communication Foundation, Version 4.0.30319.1]
Copyright (c) Microsoft Corporation.  All rights reserved.

Attempting to download metadata from '' using WS-Metadata Exchange or DISCO.
Error: Cannot import wsdl:portType
Detail: An exception was thrown while running a WSDL import extension: System.ServiceModel.Description.DataContractSerializerMessageContractImporter
Error: Schema with target namespace '' could not be found.
XPath to Error Source: //wsdl:definitions[@targetNamespace='']/wsdl:portType[@name='IMyService']

Error: Cannot import wsdl:binding
Detail: There was an error importing a wsdl:portType that the wsdl:binding is dependent on.
XPath to wsdl:portType: //wsdl:definitions[@targetNamespace='']/wsdl:portType[@name='IMyService']
XPath to Error Source: //wsdl:definitions[@targetNamespace='']/wsdl:binding[@name='WSHttpBinding_IMyService']

Error: Cannot import wsdl:port
Detail: There was an error importing a wsdl:binding that the wsdl:port is dependent on.
XPath to wsdl:binding: //wsdl:definitions[@targetNamespace='']/wsdl:binding[@name='WSHttpBinding_IMyService']
XPath to Error Source: //wsdl:definitions[@targetNamespace='']/wsdl:service[@name='MyService']/wsdl:port[@name='WSHttpBinding_IMyService']

Generating files...
Warning: No code was generated.
If you were trying to generate a client, this could be because the metadata documents did not contain any valid contracts or services
or because all contracts/services were discovered to exist in /reference assemblies. Verify that you passed all the metadata documents to the tool.

Warning: If you would like to generate data contracts from schemas make sure to use the /dataContractOnly option.

That had me completely stumped. Despite heavy googling and getting really rather cross, and reconsidering a career as a bus driver, I finally considered why it worked OK on the development box. Could it be an IIS configuration issue?

I remoted simultaneously into both the development and live boxes, and on each I fired up the IIS Manager (running IIS 7.5). Next, I went through each configuration setting on each box, comparing the values on each server.

And there's the problem: Under "SSL Settings" for the site, make sure "Require SSL" is checked, and check the Client Certificates radio button for "Accept". Problem fixed!

jQuery function to open link in new window

$(document).ready(function() {
$('A.BLAH').click(function() {
var NWin =$(this).prop('href'), '', 'height=600,width=1000');
if (window.focus)
return false;

jQuery exclude elements with certain class in selector

You can use the .not() method:

$(".content_box a").not(".button")

Alternatively, you can also use the :not() selector:

$(".content_box a:not('.button')")

There is little difference between the two approaches, except .not() is more readable (especially when chained) and :not() is very marginally faster. See this Stack Overflow answer for more info on the differences.

Can I set subject/content of email using mailto:?


Use this to experiment with mailto form elements and link encoding.

You can enter subject, body (i.e. content), etc. into the form, hit the button and see the mailto html link that you can paste into your page.

You can even specify elements that are rarely known and used: cc, bcc, from emails.

How to write trycatch in R

Here goes a straightforward example:

# Do something, or tell me why it failed
my_update_function <- function(x){
        # This is what I want to do...
        y = x * 2
        # ... but if an error occurs, tell me what happened: 
        error=function(error_message) {
            message("This is my custom message.")
            message("And below is the error message from R:")

If you also want to capture a "warning", just add warning= similar to the error= part.

endforeach in loops?

Using foreach: ... endforeach; does not only make things readable, it also makes least load for memory as introduced in PHP docs So for big apps, receiving many users this would be the best solution

c# search string in txt file

I worked a little bit the method that Rawling posted here to find more than one line in the same file until the end. This is what worked for me:

                foreach (var line in File.ReadLines(pathToFile))
                    if (line.Contains("CustomerEN") && current == null)
                        current = new List<string>();
                    else if (line.Contains("CustomerEN") && current != null)
                string s = String.Join(",", current);

jQuery hover and class selector

Your code looks fine to me.

Make sure the DOM is ready before your javascript is executed by using jQuery's $(callback) function:

$(function() {
   $('.menuItem').hover( function(){
      $(this).css('background-color', '#F00');
      $(this).css('background-color', '#000');

How to pass table value parameters to stored procedure from .net code


   public static DataTable ToTableValuedParameter<T, TProperty>(this IEnumerable<T> list, Func<T, TProperty> selector)
        var tbl = new DataTable();
        tbl.Columns.Add("Id", typeof(T));

        foreach (var item in list)


        return tbl;


Get specific ArrayList item


How to convert an object to JSON correctly in Angular 2 with TypeScript

In your product.service.ts you are using stringify method in a wrong way..

Just use


instead of


i have checked your problem and after this it's working absolutely fine.

Working copy XXX locked and cleanup failed in SVN

For me, the trick was to run svn cleanup at the top of my working copy, not in the folder where I'd been working the whole time before the problem occurred.

How can I get the CheckBoxList selected values, what I have doesn't seem to work C#.NET/VisualWebPart

An elegant way to implement this would be to make an extension method, like this:

public static class Extensions
    public static List<string> GetSelectedItems(this CheckBoxList cbl)
        var result = new List<string>();

        foreach (ListItem item in cbl.Items)
            if (item.Selected)

        return result;

I can then use something like this to compose a string will all values separated by ';':

string.Join(";", cbl.GetSelectedItems());

How to post JSON to PHP with curl

I believe you are getting an empty array because PHP is expecting the posted data to be in a Querystring format (key=value&key1=value1).

Try changing your curl request to:

curl -i -X POST -d 'json={"screencast":{"subject":"tools"}}'  \

and see if that helps any.

How to determine if a string is a number with C++?

Here's another way of doing it using the <regex> library:

bool is_integer(const std::string & s){
    return std::regex_match(s, std::regex("[(-|+)|][0-9]+"));

Difference between Math.Floor() and Math.Truncate()

Math.Floor() :

It gives the largest integer less than or equal to the given number.

    Math.Floor(3.45) =3
    Math.Floor(-3.45) =-4


It removes the decimal places of the number and replace with zero


Also from above examples we can see that floor and truncate are same for positive numbers.

What is the difference between resource and endpoint?


Resource is a RESTful subset of Endpoint.

An endpoint by itself is the location where a service can be accessed:    # Serves HTML                   # Serves DNS
/services/service.asmx    # Serves an ASP.NET Web Service

A resource refers to one or more nouns being served, represented in namespaced fashion, because it is easy for humans to comprehend:

/api/users/johnny         # Look up johnny from a users collection.
/v2/books/1234            # Get book with ID 1234 in API v2 schema.

All of the above could be considered service endpoints, but only the bottom group would be considered resources, RESTfully speaking. The top group is not expressive regarding the content it provides.

A REST request is like a sentence composed of nouns (resources) and verbs (HTTP methods):

  • GET (method) the user named johnny (resource).
  • DELETE (method) the book with id 1234 (resource).


Endpoint typically refers to a service, but resource could mean a lot of things. Here are some examples of resource that are dependent on the context they're used in.

URL: Uniform "Resource" Locator

  • Could be RESTful, but often is not. In this case, endpoint is almost synonymous.

Resource Management


Something that can be used to help you:

The library was a valuable resource, and he frequently made use of it.

Resources are natural substances such as water and wood which are valuable in supporting life:

[ pl ] The earth has limited resources, and if we don’t recycle them we use them up.

Resources are also things of value such as money or possessions that you can use when you need them:

[ pl ] The government doesn’t have the resources to hire the number of teachers needed.

The Moral

The term resource by definition has a lot of nuance. It all depends on the context its used in.

Unmarshaling nested JSON objects

Yes. With gjson all you have to do now is:

bar := gjson.Get(json, "")

bar could be a struct property if you like. Also, no maps.

Custom height Bootstrap's navbar

You need also to set .min-height: 0px; please see bellow:

.navbar-inner {
    min-height: 0px;

.navbar-nav li a {
    line-height: 150px;
    height: 150px;
    padding-top: 0;

If you set .min-height: 0px; then you can choose any height you want!

Good Luck!

How to overwrite the output directory in spark

  val jobName = "WordCount";
  //overwrite the output directory in spark  set("spark.hadoop.validateOutputSpecs", "false")
  val conf = new 
  SparkConf().setAppName(jobName).set("spark.hadoop.validateOutputSpecs", "false");
  val sc = new SparkContext(conf)

Print line numbers starting at zero using awk

NR starts at 1, so use

awk '{print NR-1 "," $0}'

Correct way to use get_or_create?

get_or_create() returns a tuple:

customer.source, created  = Source.objects.get_or_create(name="Website")
  • created ? has a boolean value, is created or not.

  • customer.source ? has an object of get_or_create() method.

Where does the .gitignore file belong?

In the simple case, a repository might have a single .gitignore file in its root directory, which applies recursively to the entire repository. However, it is also possible to have additional .gitignore files in subdirectories. The rules in these nested .gitignore files apply only to the files under the directory where they are located. The Linux kernel source repository has 206 .gitignore files.

-- this is what i read from progit.pdf(version 2), P32

Reset CSS display property to default value

No, it is generally not possible. Once some CSS (or HTML) code sets a value for a property on an element, there is no way to undo it and tell the browser to use its default value.

It is of course possible to set a property a value that you expect to be the default value. This may work rather widely if you check the Rendering section of HTML5 CR, mostly reflecting what browsers actually do.

Still, the answer is “No”, because browsers may have whatever default values they like. You should analyze what was the reason for wanting to reset to defaults; the original problem may still be solvable.

How can I make a SQL temp table with primary key and auto-incrementing field?

you dont insert into identity fields. You need to specify the field names and use the Values clause

insert into #tmp (AssignedTo, field2, field3) values (value, value, value)

If you use do a insert into... select field field field it will insert the first field into that identity field and will bomb

How do I concatenate strings in Swift?

You can add a string in these ways:

  • str += ""
  • str = str + ""
  • str = str + str2
  • str = "" + ""
  • str = "\(variable)"
  • str = str + "\(variable)"

I think I named them all.

Attach to a processes output for viewing

How would I 'attach' a console/terminal-view to an applications output so I can see what it may be saying?

About this question, I know it is possible to catch the output, even when you didn't launch sceen command before launching the processus.

While I never tried it, I've found an interesting article which explains how to do using GDB (and without restarting your process).



  1. Check the open files list for your process, thanks to /proc/xxx/fd
  2. Attach your process with GDB
  3. While it is paused, close the file you are interested in, calling close() function (you can any function of your process in GDB. I suspect you need debug symbols in your process..)
  4. Open the a new file calling the create() or open() function. (Have a look in comments at the end, you'll see people suggest to use dup2() to ensure the same handle will be in use)
  5. Detach the process and let in run.

By the way, if you are running a linux OS on i386 box, comments are talking about a better tool to redirect output to a new console : 'retty' . If so, consider its use.

How to pad a string with leading zeros in Python 3

I suggest this ugly method but it works:

length = 1
lenghtafterpadding = 3
newlength = '0' * (lenghtafterpadding - len(str(length))) + str(length)

I came here to find a lighter solution than this one!

How to mount the android img file under linux?

I have found that Furius ISO mount works best for me. I am using a Debian based distro Knoppix. I use this to Open system.img files all the time.

Furius ISO mount:

"When I want to mount userdata.img by mount -o loop userdata.img /mnt/userdata (the same as system.img), it tells me mount: you must specify the filesystem type so I try the mount -t ext2 -o loop userdata.img /mnt/userdata, it said mount: wrong fs type, bad option, bad superblock on...

So, how to get the file from the inside of userdata.img?" To load .img files you have to select loop and load the .img Select loop

Next you select mount Select mount

Furius ISO mount handles all the other options loading the .img file to your /home/dir.

What is the difference between a .cpp file and a .h file?

A header (.h, .hpp, ...) file contains

  • Class definitions ( class X { ... }; )
  • Inline function definitions ( inline int get_cpus() { ... } )
  • Function declarations ( void help(); )
  • Object declarations ( extern int debug_enabled; )

A source file (.c, .cpp, .cxx) contains

  • Function definitions ( void help() { ... } or void X::f() { ... } )
  • Object definitions ( int debug_enabled = 1; )

However, the convention that headers are named with a .h suffix and source files are named with a .cpp suffix is not really required. One can always tell a good compiler how to treat some file, irrespective of its file-name suffix ( -x <file-type> for gcc. Like -x c++ ).

Source files will contain definitions that must be present only once in the whole program. So if you include a source file somewhere and then link the result of compilation of that file and then the one of the source file itself together, then of course you will get linker errors, because you have those definitions now appear twice: Once in the included source file, and then in the file that included it. That's why you had problems with including the .cpp file.

Execute another jar in a Java program

If the jar's in your classpath, and you know its Main class, you can just invoke the main class. Using DITA-OT as an example:

import org.dita.dost.invoker.CommandLineInvoker;
CommandLineInvoker.main('-f', 'html5', '-i', 'samples/sequence.ditamap', '-o', 'test')

Note this will make the subordinate jar share memory space and a classpath with your jar, with all the potential for interference that can cause. If you don't want that stuff polluted, you have other options, as mentioned above - namely:

  • create a new ClassLoader with the jar in it. This is more safe; you can at least isolate the new jar's knowledge to a core classloader if you architect things with the knowledge that you'll be making use of alien jars. It's what we do in my shop for our plugins system; the main application is a tiny shell with a ClassLoader factory, a copy of the API, and knowledge that the real application is the first plugin for which it should build a ClassLoader. Plugins are a pair of jars - interface and implementation - that are zipped up together. The ClassLoaders all share all the interfaces, while each ClassLoader only has knowledge of its own implementation. The stack's a little complex, but it passes all tests and works beautifully.
  • use Runtime.getRuntime.exec(...) (which wholly isolates the jar, but has the normal "find the application", "escape your strings right", "platform-specific WTF", and "OMG System Threads" pitfalls of running system commands.


Try this:

INSERT INTO `center_course_fee` (`fk_course_id`,`fk_center_code`,`course_fee`) VALUES ('69', '4920153', '6000') ON DUPLICATE KEY UPDATE `course_fee` = '6000';

ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2)

I can't explain it, but in kubuntu 12.04.2 after

sudo apt-get autoremove linux-headers-3.2.0-37 linux-headers-3.2.0-37-generic

it started to work

ArrayList insertion and retrieval order

Yes, ArrayList is an ordered collection and it maintains the insertion order.

Check the code below and run it:

public class ListExample {

    public static void main(String[] args) {
        List<String> myList = new ArrayList<String>();
        System.out.println("Inserted in 'order': ");
        System.out.println("Inserted out of 'order': ");

        // Clear the list

    private static void printList(List<String> myList) {
        for (String string : myList) {

Produces the following output:

Inserted in 'order': 

Inserted out of 'order': 

For detailed information, please refer to documentation: List (Java Platform SE7)

No space left on device

Maybe you are out of inodes. Try df -i

                     2591792  136322 2455470    6% /home
/dev/sdb1            1887488 1887488       0  100% /data

Disk used 6% but inode table full.

Where can I find php.ini?

Run this in the command line:

php -r "echo php_ini_loaded_file().PHP_EOL;"

How do I make an editable DIV look like a text field?

These look the same as their real counterparts in Safari, Chrome, and Firefox. They degrade gracefully and look OK in Opera and IE9, too.



textarea {
    height: 28px;
    width: 400px;

#textarea {
    -moz-appearance: textfield-multiline;
    -webkit-appearance: textarea;
    border: 1px solid gray;
    font: medium -moz-fixed;
    font: -webkit-small-control;
    height: 28px;
    overflow: auto;
    padding: 2px;
    resize: both;
    width: 400px;

input {
    margin-top: 5px;
    width: 400px;

#input {
    -moz-appearance: textfield;
    -webkit-appearance: textfield;
    background-color: white;
    background-color: -moz-field;
    border: 1px solid darkgray;
    box-shadow: 1px 1px 1px 0 lightgray inset;  
    font: -moz-field;
    font: -webkit-small-control;
    margin-top: 5px;
    padding: 2px 3px;
    width: 398px;    


<textarea>I am a textarea</textarea>
<div id="textarea" contenteditable>I look like textarea</div>

<input value="I am an input" />
<div id="input" contenteditable>I look like an input</div>


enter image description here

How to get the children of the $(this) selector?

$(document).ready(function() {_x000D_
  // When you click the DIV, you take it with "this"_x000D_
  $('#my_div').click(function() {_x000D_'Initializing the tests..');_x000D_
    console.log('Method #1: '+$(this).children('img'));_x000D_
    console.log('Method #2: '+$(this).find('img'));_x000D_
    // Here, i'm selecting the first ocorrence of <IMG>_x000D_
    console.log('Method #3: '+$(this).find('img:eq(0)'));_x000D_
  background-color: yellow;_x000D_
  width: 100%;_x000D_
  height: 200px;_x000D_
<script src=""></script>_x000D_
<div id="my_div" class="the_div">_x000D_
  <img src="...">_x000D_


I wouldn't bother doing it in Linq2SQL. Create a stored Procedure for the query you want and understand and then create the object to the stored procedure in the framework or just connect direct to it.

How To: Best way to draw table in console app (C#)

It's easier in!

If you want the user to be able to manually enter data into a table:

Console.Write("Enter Data For Column 1: ")
    Dim Data1 As String = Console.ReadLine
    Console.Write("Enter Data For Column 2: ")
    Dim Data2 As String = Console.ReadLine

    Console.WriteLine("{0,-20} {1,-10} {2,-10}", "{Data Type}", "{Column 1}", "{Column 2}")
    Console.WriteLine("{0,-20} {1,-10} {2,-10}", "Data Entered:", Data1, Data2)

    Console.WriteLine("ENTER To Exit: ")

It should look like this:

It should look like this (Click Me).

error while loading shared libraries:

error while loading shared libraries:

If you see this, your distro probably has a newer version of libncurse installed. First find out what version of libncurses your distro has:

$ ls -1 /usr/lib/libncurses*

In this case, we are dealing with version 6, so we make two symlinks:

$ sudo ln -s /usr/lib/ /usr/lib/
$ sudo ln -s /usr/lib/ /usr/lib/

After this, the program should run normally.

react-native - Fit Image in containing View, not the whole screen size

I could not get the example working using the resizeMode properties of Image, but because the images will all be square there is a way to do it using the Dimensions of the window along with flexbox.

Set flexDirection: 'row', and flexWrap: 'wrap', then they will all line up as long as they are all the same dimensions.

I set it up here

"use strict";

var React = require("react-native");
var {
} = React;

var deviceWidth = Dimensions.get("window").width;
var temp = "";
var SampleApp = React.createClass({
  render: function() {
    var images = [];

    for (var i = 0; i < 10; i++) {
        <TouchableOpacity key={i} activeOpacity={0.75} style={styles.item}>
          <Image style={styles.image} source={{ uri: temp }} />

    return (
      <ScrollView style={{ flex: 1 }}>
        <View style={styles.container}>

How to get the previous URL in JavaScript?

If anyone is coming from React-world, I ended up solving my use-case using a combination of history-library, useEffect and localStorage

When user selects new project:

  function selectProject(customer_id: string, project_id: string){
    const projectUrl = `/customer/${customer_id}/project/${project_id}`
    localStorage.setItem("selected-project", projectUrl)

When user comes back from another website. If there's something in localStorage, send him there.

  useEffect(() => {
    const projectUrl = localStorage.getItem("selected-project")
    if (projectUrl) {
  }, [history])

When user has exited a project, empty localStorage

  const selectProject = () => {