Programs & Examples On #Spymemcached

Spymemcached is a single-threaded, asynchronous memcached client written in java.

Why call git branch --unset-upstream to fixup?

I had this question twice, and it was always caused by the corruption of the git cache file at my local branch. I fixed it by writing the missing commit hash into that file. I got the right commit hash from the server and ran the following command locally:

cat .git/refs/remotes/origin/feature/mybranch \
echo 1edf9668426de67ab764af138a98342787dc87fe \
>> .git/refs/remotes/origin/feature/mybranch

How do I check how many options there are in a dropdown menu?

With pure javascript you can just call the length on the id of the select box. It will be more faster. Typically with everything native javascript is performing better and better with modern browsers

This can be achieved in javascript by

     var dropdownFilterSite = document.querySelector( '#dropDownId' );  //Similar to jQuery

var length = dropdownFilterSite.length.

Good website for some learning

A good video to watch by Todd Motto

Find character position and update file name

If you use Excel, then the command would be Find and MID. Here is what it would look like in Powershell.

 $text = "asdfNAME=PC123456<>Diweursejsfdjiwr"

asdfNAME=PC123456<>Diweursejsfdjiwr - Randon line of text, we want PC123456


7 - this is the "FIND" command for Powershell


C1234 - this is the "MID" command for Powershell


PC123456 - tada it has found and cut our text


How to use hex color values

extension UIColor {

      convenience init(hex: Int, alpha: Double = 1.0) {

      self.init(red: CGFloat((hex>>16)&0xFF)/255.0, green:CGFloat((hex>>8)&0xFF)/255.0, blue: CGFloat((hex)&0xFF)/255.0, alpha:  CGFloat(255 * alpha) / 255)

Use this extension like:

let selectedColor = UIColor(hex: 0xFFFFFF)
let selectedColor = UIColor(hex: 0xFFFFFF, alpha: 0.5)

How to lazy load images in ListView in Android

I have followed this Android Training and I think it does an excellent job at downloading images without blocking the main UI. It also handles caching and dealing with scrolling through many images: Loading Large Bitmaps Efficiently

How can I add 1 day to current date?

To add one day to a date object:

var date = new Date();

// add a day
date.setDate(date.getDate() + 1);

Function overloading in Python: Missing

You can pass a mutable container datatype into a function, and it can contain anything you want.

If you need a different functionality, name the functions differently, or if you need the same interface, just write an interface function (or method) that calls the functions appropriately based on the data received.

It took a while to me to get adjusted to this coming from Java, but it really isn't a "big handicap".

Fast way of finding lines in one file that are not in another?

The comm command (short for "common") may be useful comm - compare two sorted files line by line

#find lines only in file1
comm -23 file1 file2 

#find lines only in file2
comm -13 file1 file2 

#find lines common to both files
comm -12 file1 file2 

The man file is actually quite readable for this.

How do you force Visual Studio to regenerate the .designer files for aspx/ascx files?

Within the Visual Studio:

1) Remove your aspx.designer.cs file

2) Right click on your aspx file and select "Convert to Web Application" This should add the aspx.designer.cs back and up to date.

If you get an error saying:

"Generation of designer file failed: The method or operation is not implemented."

Try close Visual Studio and then reopen your project and do step number two again

How to generate aspx.designer.cs in visual studio?

Using prepared statements with JDBCTemplate

Try the following:

PreparedStatementCreator creator = new PreparedStatementCreator() {
    public PreparedStatement createPreparedStatement(Connection con) throws SQLException {
        PreparedStatement updateSales = con.prepareStatement(
        updateSales.setInt(1, 75); 
        updateSales.setString(2, "Colombian"); 
        return updateSales;

how to add key value pair in the JSON object already declared

You can use dot notation or bracket notation ...

var obj = {};
obj = {
  "1": "aa",
  "2": "bb"

obj.another = "valuehere";
obj["3"] = "cc";

What rules does software version numbering follow?

The usual method I have seen is X.Y.Z, which generally corresponds to major.minor.patch:

  • Major version numbers change whenever there is some significant change being introduced. For example, a large or potentially backward-incompatible change to a software package.
  • Minor version numbers change when a new, minor feature is introduced or when a set of smaller features is rolled out.
  • Patch numbers change when a new build of the software is released to customers. This is normally for small bug-fixes or the like.

Other variations use build numbers as an additional identifier. So you may have a large number for if you have many revisions that are tested between releases. I use a couple of packages that are identified by year/month or year/release. Thus, a release in the month of September of 2010 might be 2010.9 or 2010.3 for the 3rd release of this year.

There are many variants to versioning. It all boils down to personal preference.

For the "1.3v1.1", that may be two different internal products, something that would be a shared library / codebase that is rev'd differently from the main product; that may indicate version 1.3 for the main product, and version 1.1 of the internal library / package.

SQLSTATE[HY000] [1045] Access denied for user 'username'@'localhost' using CakePHP

I want to add to the answers posted on above that none of the solutions proposed here worked for me. My WAMP, is working on port 3308 instead of 3306 which is what it is installed by default. I found out that when working in a local environment, if you are using mysqladmin in your computer (for testing environment), and if you are working with port other than 3306, you must define your variable DB_SERVER with the value localhost:NumberOfThePort, so it will look like the following: define("DB_SERVER", "localhost:3308"). You can obtain this value by right-clicking on the WAMP icon in your taskbar (on the hidden icons section) and select Tools. You will see the section: "Port used by MySQL: NumberOfThePort"

This will fix your connection to your database.

This was the error I got: Error: SQLSTATE[HY1045] Access denied for user 'username'@'localhost' on line X.

I hope this helps you out.


How do I add PHP code/file to HTML(.html) files?

I think writing PHP into an .html file is confusing and anti-natural. Why would you do that??

Anyway, if what you want is to execute PHP files and show them as .html in the address bar, an easiest solution would be using .php as normal, and write a rule in your .htaccess like this:

RewriteRule ^([^.]+)\.html$ $1.php [L]

How to execute shell command in Javascript

...few year later...

ES6 has been accepted as a standard and ES7 is around the corner so it deserves updated answer. We'll use ES6+async/await with nodejs+babel as an example, prerequisites are:

Your example foo.js file may look like:

import { exec } from 'child_process';

 * Execute simple shell command (async wrapper).
 * @param {String} cmd
 * @return {Object} { stdout: String, stderr: String }
async function sh(cmd) {
  return new Promise(function (resolve, reject) {
    exec(cmd, (err, stdout, stderr) => {
      if (err) {
      } else {
        resolve({ stdout, stderr });

async function main() {
  let { stdout } = await sh('ls');
  for (let line of stdout.split('\n')) {
    console.log(`ls: ${line}`);


Make sure you have babel:

npm i babel-cli -g

Install latest preset:

npm i babel-preset-latest

Run it via:

babel-node --presets latest foo.js

How to convert Map keys to array?

You can use the spread operator to convert Map.keys() iterator in an Array.

let myMap = new Map().set('a', 1).set('b', 2).set(983, true)_x000D_
let keys = [...myMap.keys()]_x000D_

Compare two Lists for differences

This solution produces a result list, that contains all differences from both input lists. You can compare your objects by any property, in my example it is ID. The only restriction is that the lists should be of the same type:

var DifferencesList = ListA.Where(x => !ListB.Any(x1 => ==
            .Union(ListB.Where(x => !ListA.Any(x1 => ==;

Convert System.Drawing.Color to RGB and Hex Value

I'm failing to see the problem here. The code looks good to me.

The only thing I can think of is that the try/catch blocks are redundant -- Color is a struct and R, G, and B are bytes, so c can't be null and c.R.ToString(), c.G.ToString(), and c.B.ToString() can't actually fail (the only way I can see them failing is with a NullReferenceException, and none of them can actually be null).

You could clean the whole thing up using the following:

private static String HexConverter(System.Drawing.Color c)
    return "#" + c.R.ToString("X2") + c.G.ToString("X2") + c.B.ToString("X2");

private static String RGBConverter(System.Drawing.Color c)
    return "RGB(" + c.R.ToString() + "," + c.G.ToString() + "," + c.B.ToString() + ")";

git diff file against its last change

One of the ways to use git diff is:

git diff <commit> <path>

And a common way to refer one commit of the last commit is as a relative path to the actual HEAD. You can reference previous commits as HEAD^ (in your example this will be 123abc) or HEAD^^ (456def in your example), etc ...

So the answer to your question is:

git diff HEAD^^ myfile


To add to those who have mentioned the implicit rules, it's best to see what make has defined implicitly and for your env using:

make -p

For instance:

%.o: %.c

which expands


This will also print # environment data. Here, you will find GCC's include path among other useful info.


In make, when it comes to search, the paths are many, the light is one... or something to that effect.

  1. C_INCLUDE_PATH is system-wide, set it in your shell's *.rc.
  2. $(CPPFLAGS) is for the preprocessor include path.
  3. If you need to add a general search path for make, use:
VPATH = my_dir_to_search

... or even more specific

vpath %.c src
vpath %.h include

make uses VPATH as a general search path so use cautiously. If a file exists in more than one location listed in VPATH, make will take the first occurrence in the list.

CSS3 Spin Animation

@keyframes spin {
    from {transform:rotate(0deg);}
    to {transform:rotate(360deg);}

this will make you to answer the question

Show how many characters remaining in a HTML text box using JavaScript

Try the following code for instance:

working code in

For textArea, use this:

<textarea id="txtBox"></textarea>

For textBox, use this:

<input type="text" id="txtBox"/>
<input type="text" id="counterBox"/>
 var txtBoxRef = document.querySelector("#txtBox");
 var counterRef = document.querySelector("#counterBox");
  var remLength = 0;
  remLength = 160 - parseInt(txtBoxRef.value.length);
  if(remLength < 0)
    txtBoxRef.value = txtBoxRef.value.substring(0, 160);
    return false;
  counterRef.value = remLength + " characters remaining...";

Hope this Helps!

How do I create a Bash alias?

You can add an alias or a function in your startup script file. Usually this is .bashrc, .bash_login or .profile file in your home directory.

Since these files are hidden you will have to do an ls -a to list them. If you don't have one you can create one.

If I remember correctly, when I had bought my Mac, the .bash_login file wasn't there. I had to create it for myself so that I could put prompt info, alias, functions, etc. in it.

Here are the steps if you would like to create one:

  1. Start up Terminal
  2. Type cd ~/ to go to your home folder
  3. Type touch .bash_profile to create your new file.
  4. Edit .bash_profile with your favorite editor (or you can just type open -e .bash_profile to open it in TextEdit.
  5. Type . .bash_profile to reload .bash_profile and update any alias you add.

How to import a class from default package

From the Java language spec:

It is a compile time error to import a type from the unnamed package.

You'll have to access the class via reflection or some other indirect method.

Error - Android resource linking failed (AAPT2 27.0.3 Daemon #0)

The Android resource linking failed error can also appear if you have an error in any of your XML resources. In my case I was using the following line twice in one of my XML drawables in drawable folder:

<?xml version="1.0" encoding="UTF-8"?>
<?xml version="1.0" encoding="UTF-8"?>

I removed the duplicate line and the error disappeared. The error was a bit misleading:

Android resource linking failed Output: /Users/johndoe/Desktop/myapp/app/src/main/res/layout/activity_main.xml:2: error: resource drawable/bg_main (aka com.example.myproject:drawable/bg_main) not found.

According to the above error, the first thing you need to do is to proof read all the drawable resources that are accessed in the activity_main because the chances are higher that you will find the error. In the worst case scenario you might end up checking all your resource files.

Excel Define a range based on a cell value

This should be close to what you are looking for your first example:


This should be close to what you are looking for your final example:


jQuery: how do I animate a div rotation?

This works for me:

function animateRotate (object,fromDeg,toDeg,duration){
    var dummy = $('<span style="margin-left:'+fromDeg+'px;">')
        step: function(now,fx){
            $(object).css('transform','rotate(' + now + 'deg)');

How can I determine installed SQL Server instances and their versions?

-- T-SQL Query to find list of Instances Installed on a machine

( Value nvarchar(100),
 InstanceNames nvarchar(100),
 Data nvarchar(100))

Insert into @GetInstances
EXECUTE xp_regread
  @rootkey = 'HKEY_LOCAL_MACHINE',
  @key = 'SOFTWARE\Microsoft\Microsoft SQL Server',
  @value_name = 'InstalledInstances'

Select InstanceNames from @GetInstances 

Live video streaming using Java?

Hi not an expert in streaming but my understanding is that it is included in th Java Media Framework JMF

Maven build debug in Eclipse

probleme : unit test result are not the same runing with eclipse and maven due ti order of library used by eclipse and maven. In my case the test was success with maven but i want to debug my unit test using eclipse, so the most easy way to debug unit test class with eclipse and runing maven is :

1) mvn -Dtest=MySuperClassTest -Dmaven.surefire.debug test ==> it will listen to the 5005 port (default port)

2) Go to eclipse, open a debug configuration, add a new java remote application and change the port to 5005 and debug

3) of course you must add break point somewhere in the class that you want to debug

Dynamic loading of images in WPF

Here is the extension method to load an image from URI:

public static BitmapImage GetBitmapImage(
    this Uri imageAbsolutePath,
    BitmapCacheOption bitmapCacheOption = BitmapCacheOption.Default)
    BitmapImage image = new BitmapImage();
    image.CacheOption = bitmapCacheOption;
    image.UriSource = imageAbsolutePath;

    return image;

Sample of use:

Uri _imageUri = new Uri(imageAbsolutePath);
ImageXamlElement.Source = _imageUri.GetBitmapImage(BitmapCacheOption.OnLoad);

Simple as that!

How to read a text file into a list or an array with Python

You can also use numpy loadtxt like

from numpy import loadtxt
lines = loadtxt("filename.dat", comments="#", delimiter=",", unpack=False)

How to get height of <div> in px dimension

There is a built-in method to get the bounding rectangle: Element.getBoundingClientRect.

The result is the smallest rectangle which contains the entire element, with the read-only left, top, right, bottom, x, y, width, and height properties.

See the example below:

let innerBox = document.getElementById("myDiv").getBoundingClientRect().height;_x000D_
document.getElementById("data_box").innerHTML = "height: " + innerBox;
body {_x000D_
  margin: 0;_x000D_
.relative {_x000D_
  width: 220px;_x000D_
  height: 180px;_x000D_
  position: relative;_x000D_
  background-color: purple;_x000D_
.absolute {_x000D_
  position: absolute;_x000D_
  top: 30px;_x000D_
  left: 20px;_x000D_
  background-color: orange;_x000D_
  padding: 30px;_x000D_
  overflow: hidden;_x000D_
#myDiv {_x000D_
  margin: 20px;_x000D_
  padding: 10px;_x000D_
  color: red;_x000D_
  font-weight: bold;_x000D_
  background-color: yellow;_x000D_
#data_box {_x000D_
  font: 30px arial, sans-serif;_x000D_
Get height of <mark>myDiv</mark> in px dimension:_x000D_
<div id="data_box"></div>_x000D_
<div class="relative">_x000D_
  <div class="absolute">_x000D_
    <div id="myDiv">myDiv</div>_x000D_

The POST method is not supported for this route. Supported methods: GET, HEAD. Laravel

I know this is not the solution to OPs post. However, this post is the first one indexed by Google when I searched for answers to this error. For this reason I feel this will benefit others.

The following error...

The POST method is not supported for this route. Supported methods: GET, HEAD.

was caused by not clearing the routing cache

php artisan route:cache

How to run a Maven project from Eclipse?

Your Maven project doesn't seem to be configured as a Eclipse Java project, that is the Java nature is missing (the little 'J' in the project icon).

To enable this, the <packaging> element in your pom.xml should be jar (or similar).

Then, right-click the project and select Maven > Update Project Configuration

For this to work, you need to have m2eclipse installed. But since you had the _ New ... > New Maven Project_ wizard, I assume you have m2eclipse installed.

Is there any way of configuring Eclipse IDE proxy settings via an autoproxy configuration script?

Download proxy script and check last line for return statement Proxy IP and Port.
Add this IP and Port using these step.

   1.  Windows -->Preferences-->General -->Network Connection
   2. Select Active Provider : Manual
   3.  Proxy entries select HTTP--> Click on Edit button
   4.  Then add Host as a proxy IP and port left Required Authentication blank.
   5.  Restart eclipse
   6.  Now Eclipse Marketplace... working.

AngularJS ng-click to go to another page (with Ionic framework)

Use <a> with href instead of a <button> solves my problem.

<ion-nav-buttons side="secondary">
  <a class="button icon-right ion-plus-round" href="#/app/gosomewhere"></a>

Simplest way to restart service on a remote computer

look at sysinternals for a variety of tools to help you achieve that goal. psService for example would restart a service on a remote machine.

Should I use the Reply-To header when sending emails as a service to others?

You may want to consider placing the customer's name in the From header and your address in the Sender header:

From: Company A <[email protected]>
Sender: [email protected]

Most mailers will render this as "From [email protected] on behalf of Company A", which is accurate. And then a Reply-To of Company A's address won't seem out of sorts.

From RFC 5322:

The "From:" field specifies the author(s) of the message, that is, the mailbox(es) of the person(s) or system(s) responsible for the writing of the message. The "Sender:" field specifies the mailbox of the agent responsible for the actual transmission of the message. For example, if a secretary were to send a message for another person, the mailbox of the secretary would appear in the "Sender:" field and the mailbox of the actual author would appear in the "From:" field.

How to search for a file in the CentOS command line

Try this command:

find / -name file.look

How to use if statements in LESS

I wrote a mixin for some syntactic sugar ;)
Maybe someone likes this way of writing if-then-else better than using guards

depends on Less 1.7.0


.if(isnumber(2), {
        log {
            isnumber: true;
        log {
            isnumber: false;

.if(lightness(#fff) gt (20% * 2), {
        log {
            is-light: true;

using on example from above

.if(@debug, {
        header {
            background-color: yellow;
            #title {
                background-color: orange;
        article {
            background-color: red;

Google Chromecast sender error if Chromecast extension is not installed or using incognito

By default Chrome extensions do not run in Incognito mode. You have to explicitly enable the extension to run in Incognito.

Why am I getting the message, "fatal: This operation must be run in a work tree?"

Same issue i got, i did following steps,

  1. git init
  2. git add .
  3. git commit -m"inital setup"
  4. git push -f origin master

then it work starts working.

Model backing a DB Context has changed; Consider Code First Migrations

Just go to Package Manage Console, type the following:


*If the error like this appears "Unable to update database to match the current model because there are pending changes and automatic migration is disabled. Either write the pending model changes to a code-based migration or enable automatic migration."

Do this >>> Add-Migration

*Visual studio will ask for a name, kindly input the name you want.


Entity framework code-first null foreign key

I have the same problem now , I have foreign key and i need put it as nullable, to solve this problem you should put

        .HasMany(c => c.Users)
        .WithOptional(c => c.Country)
        .HasForeignKey(c => c.CountryId)

in DBContext class I am sorry for answer you very late :)

Formatting a number with exactly two decimals in JavaScript

Using this response by reference:

I build a function to get dynamic numbers of decimals:

function toDec(num, dec)
        if(typeof dec=='undefined' || dec<0)
                dec = 2;

        var tmp = dec + 1;
        for(var i=1; i<=tmp; i++)
                num = num * 10;

        num = num / 10;
        num = Math.round(num);
        for(var i=1; i<=dec; i++)
                num = num / 10;

        num = num.toFixed(dec);

        return num;

here working example:

Node.js Best Practice Exception Handling

You can catch uncaught exceptions, but it's of limited use. See

monit, forever or upstart can be used to restart node process when it crashes. A graceful shutdown is best you can hope for (e.g. save all in-memory data in uncaught exception handler).

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

A good rule of thumb is ".h files should have declarations [potentially] used by multiple source files, but no code that gets run."

Division of integers in Java

In Java
Integer/Integer = Integer
Integer/Double = Double//Either of numerator or denominator must be floating point number
1/10 = 0
1.0/10 = 0.1
1/10.0 = 0.1

Just type cast either of them.

Passing multiple values for a single parameter in Reporting Services

If you want to pass multiple values to RS via a query string all you need to do is repeat the report parameter for each value.

For example; I have a RS column called COLS and this column expects one or more values.

&rp:COLS=1&rp:COLS=1&rp:COLS=5 etc..

How can I change eclipse's Internal Browser from IE to Firefox on Windows XP?

You can find out the option for changing browser in Window menu.

See image at below.

enter image description here

This image can be easy to understand.

What are the differences between a multidimensional array and an array of arrays in C#?

A multidimensional array creates a nice linear memory layout while a jagged array implies several extra levels of indirection.

Looking up the value jagged[3][6] in a jagged array var jagged = new int[10][5] works like this: Look up the element at index 3 (which is an array) and look up the element at index 6 in that array (which is a value). For each dimension in this case, there's an additional look up (this is an expensive memory access pattern).

A multidimensional array is laid out linearly in memory, the actual value is found by multiplying together the indexes. However, given the array var mult = new int[10,30], the Length property of that multidimensional array returns the total number of elements i.e. 10 * 30 = 300.

The Rank property of a jagged array is always 1, but a multidimensional array can have any rank. The GetLength method of any array can be used to get the length of each dimension. For the multidimensional array in this example mult.GetLength(1) returns 30.

Indexing the multidimensional array is faster. e.g. given the multidimensional array in this example mult[1,7] = 30 * 1 + 7 = 37, get the element at that index 37. This is a better memory access pattern because only one memory location is involved, which is the base address of the array.

A multidimensional array therefore allocates a continuous memory block, while a jagged array does not have to be square, e.g. jagged[1].Length does not have to equal jagged[2].Length, which would be true for any multidimensional array.


Performance wise, multidimensional arrays should be faster. A lot faster, but due to a really bad CLR implementation they are not.

 23.084  16.634  15.215  15.489  14.407  13.691  14.695  14.398  14.551  14.252 
 25.782  27.484  25.711  20.844  19.607  20.349  25.861  26.214  19.677  20.171 
  5.050   5.085   6.412   5.225   5.100   5.751   6.650   5.222   6.770   5.305 

The first row are timings of jagged arrays, the second shows multidimensional arrays and the third, well that's how it should be. The program is shown below, FYI this was tested running mono. (The windows timings are vastly different, mostly due to the CLR implementation variations).

On windows, the timings of the jagged arrays are greatly superior, about the same as my own interpretation of what multidimensional array look up should be like, see 'Single()'. Sadly the windows JIT-compiler is really stupid, and this unfortunately makes these performance discussions difficult, there are too many inconsistencies.

These are the timings I got on windows, same deal here, the first row are jagged arrays, second multidimensional and third my own implementation of multidimensional, note how much slower this is on windows compared to mono.

  8.438   2.004   8.439   4.362   4.936   4.533   4.751   4.776   4.635   5.864
  7.414  13.196  11.940  11.832  11.675  11.811  11.812  12.964  11.885  11.751
 11.355  10.788  10.527  10.541  10.745  10.723  10.651  10.930  10.639  10.595

Source code:

using System;
using System.Diagnostics;
static class ArrayPref
    const string Format = "{0,7:0.000} ";
    static void Main()

    static void Jagged()
        const int dim = 100;
        for(var passes = 0; passes < 10; passes++)
            var timer = new Stopwatch();
            var jagged = new int[dim][][];
            for(var i = 0; i < dim; i++)
                jagged[i] = new int[dim][];
                for(var j = 0; j < dim; j++)
                    jagged[i][j] = new int[dim];
                    for(var k = 0; k < dim; k++)
                        jagged[i][j][k] = i * j * k;

    static void Multi()
        const int dim = 100;
        for(var passes = 0; passes < 10; passes++)
            var timer = new Stopwatch();
            var multi = new int[dim,dim,dim];
            for(var i = 0; i < dim; i++)
                for(var j = 0; j < dim; j++)
                    for(var k = 0; k < dim; k++)
                        multi[i,j,k] = i * j * k;

    static void Single()
        const int dim = 100;
        for(var passes = 0; passes < 10; passes++)
            var timer = new Stopwatch();
            var single = new int[dim*dim*dim];
            for(var i = 0; i < dim; i++)
                for(var j = 0; j < dim; j++)
                    for(var k = 0; k < dim; k++)
                        single[i*dim*dim+j*dim+k] = i * j * k;

Redirecting new tab on button click.(Response.Redirect) in C#

Wouldn't you be better off with

<asp:HyperLink ID="HyperLink1" runat="server" 
    Click here

Because, to replicate your desired behavior on an asp:Button, you have to call on the OnClientClick event of the button which looks a lot less cleaner than the above solution. Plus asp:HyperLink is there to handle scenarios like this.

If you want to replicate this using an asp:Button, do this.

<asp:Button ID="btn" runat="Server" 
        OnClientClick="javascript:return openRequestedPopup();"/>

JavaScript function.

var windowObjectReference;

function openRequestedPopup() {
    windowObjectReference ="CMS_1.aspx",

How can I remove punctuation from input text in Java?

I don't like to use regex, so here is another simple solution.

public String removePunctuations(String s) {
    String res = "";
    for (Character c : s.toCharArray()) {
            res += c;
    return res;

Note: This will include both Letters and Digits

PHP function to build query string from array

Implode will combine an array into a string for you, but to make an SQL query out a kay/value pair you'll have to write your own function.

CSS rotation cross browser with jquery.animate()

Thanks yckart! Great contribution. I fleshed out your plugin a bit more. Added startAngle for full control and cross-browser css.

$.fn.animateRotate = function(startAngle, endAngle, duration, easing, complete){
    return this.each(function(){
        var elem = $(this);

        $({deg: startAngle}).animate({deg: endAngle}, {
            duration: duration,
            easing: easing,
            step: function(now){
            complete: complete || $.noop

How do I get the max ID with Linq to Entity?

Note that none of these answers will work if the key is a varchar since it is tempting to use MAX in a varchar column that is filled with "ints".

In a database if a column e.g. "Id" is in the database 1,2,3, 110, 112, 113, 4, 5, 6 Then all of the answers above will return 6.

So in your local database everything will work fine since while developing you will never get above 100 test records, then, at some moment during production you get a weird support ticket. Then after an hour you discover exactly this line "max" which seems to return the wrong key for some reason....

(and note that it says nowhere above that the key is INT...) (and if happens to end up in a generic library...)

So use:

Users.OrderByDescending(x=>x.Id.Length).ThenByDescending(a => a.Id).FirstOrDefault();

How do I fix this "TypeError: 'str' object is not callable" error?

this part :

"Your new price is: $"(float(price)

asks python to call this string:

"Your new price is: $"

just like you would a function: function( some_args) which will ALWAYS trigger the error:

TypeError: 'str' object is not callable

How to set the font size in Emacs?

I use hydra package to control font increase/decrease contiguously by pressing f2 + + + +/f2 - - - -, which means that press f2 once, and then using +/- to control only, and restore default font size by f2 0. Because i have keypad, so I also bind keypad to the font setting.

(defhydra hydra-zoom (global-map "<f2>")
  ("<kp-add>" text-scale-increase "in")
  ("+" text-scale-increase "in")
  ("-" text-scale-decrease "out")
  ("<kp-subtract>" text-scale-decrease "out")
  ("0" (text-scale-set 0) "reset")
  ("<kp-0>" (text-scale-set 0) "reset"))

And modern editor mouse control functionality supported by below key bindings, press control + mouse wheel to increase/decrease font.

(global-set-key (kbd "<C-wheel-up>") 'text-scale-increase)
(global-set-key (kbd "<C-wheel-down>") 'text-scale-decrease)

Delegates in swift?

The solutions above seemed a little coupled and at the same time avoid reuse the same protocol in other controllers, that's why I've come with the solution that is more strong typed using generic type-erasure.

@noreturn public func notImplemented(){
    fatalError("not implemented yet")

public protocol DataChangedProtocol: class{
    typealias DataType

    func onChange(t:DataType)

class AbstractDataChangedWrapper<DataType> : DataChangedProtocol{

    func onChange(t: DataType) {

class AnyDataChangedWrapper<T: DataChangedProtocol> : AbstractDataChangedWrapper<T.DataType>{

    var base: T

    init(_ base: T ){
        self.base = base

    override func onChange(t: T.DataType) {

class AnyDataChangedProtocol<DataType> : DataChangedProtocol{

    var base: AbstractDataChangedWrapper<DataType>

    init<S: DataChangedProtocol where S.DataType == DataType>(_ s: S){
        self.base = AnyDataChangedWrapper(s)

    func onChange(t: DataType) {

class Source : DataChangedProtocol {
    func onChange(data: String) {
        print( "got new value \(data)" )

class Target {
    var delegate: AnyDataChangedProtocol<String>?

    func reportChange(data:String ){

var source = Source()
var target = Target()

target.delegate = AnyDataChangedProtocol(source)

output: got new value newValue

Transparent background on winforms?

What works for me is using a specific color instead of the real ability of .png to represent transparency.

So, what you can do is take your background image, and paint the transparent area with a specific color (Magenta always seemed appropriate to me...).

Set the image as the Form's BackgrounImage property, and set the color as the Form's TransparencyKey. No need for changes in the Control's style, and no need for BackColor.

I've tryed it right now and it worked for me...

Select top 2 rows in Hive

Here I think it's worth mentioning SORT BY and ORDER BY both clauses and why they different,

SELECT * FROM <table_name> SORT BY <column_name> DESC LIMIT 2

If you are using SORT BY clause it sort data per reducer which means if you have more than one MapReduce task it will result partially ordered data. On the other hand, the ORDER BY clause will result in ordered data for the final Reduce task. To understand more please refer to this link.

SELECT * FROM <table_name> ORDER BY <column_name> DESC LIMIT 2

Note: Finally, Even though the accepted answer contains SORT BY clause, I mostly prefer to use ORDER BY clause for the general use case to avoid any data loss.

jquery's append not working with svg element?

If the string you need to append is SVG and you add the proper namespace, you can parse the string as XML and append to the parent.

var xml = jQuery.parseXML('<circle xmlns="" cx="100" cy="50" r="40" stroke="black" stroke-width="2" fill="red"/>');

Which type of folder structure should be used with Angular 2?

Maybe something like this structure:

|-- app
     |-- modules
       |-- home
           |-- [+] components
           |-- pages
              |-- home
              |-- home.component.ts|html|scss|spec
           |-- home-routing.module.ts
           |-- home.module.ts
     |-- core
       |-- authentication
           |-- authentication.service.ts|spec.ts
       |-- footer
           |-- footer.component.ts|html|scss|spec.ts
       |-- guards
           |-- auth.guard.ts
           |-- no-auth-guard.ts
           |-- admin-guard.ts 
       |-- http
           |-- user
               |-- user.service.ts|spec.ts
           |-- api.service.ts|spec.ts
       |-- interceptors
           |-- api-prefix.interceptor.ts
           |-- error-handler.interceptor.ts
           |-- http.token.interceptor.ts
       |-- mocks
           |-- user.mock.ts
       |-- services
           |-- srv1.service.ts|spec.ts
           |-- srv2.service.ts|spec.ts
       |-- header
           |-- header.component.ts|html|scss|spec.ts
       |-- core.module.ts
       |-- ensureModuleLoadedOnceGuard.ts
       |-- logger.service.ts
     |-- shared
          |-- components
              |-- loader
                  |-- loader.component.ts|html|scss|spec.ts
          |-- buttons
              |-- favorite-button
                  |-- favorite-button.component.ts|html|scss|spec.ts
              |-- collapse-button
                  |-- collapse-button.component.ts|html|scss|spec.ts
          |-- directives
              |-- auth.directive.ts|spec.ts
          |-- pipes
              |-- capitalize.pipe.ts
              |-- safe.pipe.ts
     |-- configs
         |-- app-settings.config.ts
         |-- dt-norwegian.config.ts
     |-- scss
          |-- [+] partials
          |-- _base.scss
          |-- styles.scss
     |-- assets

How to pass a type as a method parameter in Java

You could pass a Class<T> in.

private void foo(Class<?> cls) {
    if (cls == String.class) { ... }
    else if (cls == int.class) { ... }

private void bar() {

Update: the OOP way depends on the functional requirement. Best bet would be an interface defining foo() and two concrete implementations implementing foo() and then just call foo() on the implementation you've at hand. Another way may be a Map<Class<?>, Action> which you could call by actions.get(cls). This is easily to be combined with an interface and concrete implementations: actions.get(cls).foo().

jQuery ui dialog change title after load-callback

Even better!

    jQuery( "#dialog" ).attr('title', 'Error');
    jQuery( "#dialog" ).text('You forgot to enter your first name');

What is difference between Axios and Fetch?

  1. Fetch API, need to deal with two promises to get the response data in JSON Object property. While axios result into JSON object.

  2. Also error handling is different in fetch, as it does not handle server side error in the catch block, the Promise returned from fetch() won’t reject on HTTP error status even if the response is an HTTP 404 or 500. Instead, it will resolve normally (with ok status set to false), and it will only reject on network failure or if anything prevented the request from completing. While in axios you can catch all error in catch block.

I will say better to use axios, straightforward to handle interceptors, headers config, set cookies and error handling.

Refer this

How can I create a dropdown menu from a List in Tkinter?

To create a "drop down menu" you can use OptionMenu in tkinter

Example of a basic OptionMenu:

from Tkinter import *

master = Tk()

variable = StringVar(master)
variable.set("one") # default value

w = OptionMenu(master, variable, "one", "two", "three")


More information (including the script above) can be found here.

Creating an OptionMenu of the months from a list would be as simple as:

from tkinter import *

] #etc

master = Tk()

variable = StringVar(master)
variable.set(OPTIONS[0]) # default value

w = OptionMenu(master, variable, *OPTIONS)


In order to retrieve the value the user has selected you can simply use a .get() on the variable that we assigned to the widget, in the below case this is variable:

from tkinter import *

] #etc

master = Tk()

variable = StringVar(master)
variable.set(OPTIONS[0]) # default value

w = OptionMenu(master, variable, *OPTIONS)

def ok():
    print ("value is:" + variable.get())

button = Button(master, text="OK", command=ok)


I would highly recommend reading through this site for further basic tkinter information as the above examples are modified from that site.

Using fonts with Rails asset pipeline

I was having this problem on Rails 4.2 (with ruby 2.2.3) and had to edit the font-awesome _paths.scss partial to remove references to $fa-font-path and removing a leading forward slash. The following was broken:

@font-face {
  font-family: 'FontAwesome';
  src: font-url('#{$fa-font-path}/fontawesome-webfont.eot?v=#{$fa-version}');
  src: font-url('#{$fa-font-path}/fontawesome-webfont.eot?#iefix&v=#{$fa-version}') format('embedded-opentype'),
    font-url('#{$fa-font-path}/fontawesome-webfont.woff2?v=#{$fa-version}') format('woff2'),
    font-url('#{$fa-font-path}/fontawesome-webfont.woff?v=#{$fa-version}') format('woff'),
    font-url('#{$fa-font-path}/fontawesome-webfont.ttf?v=#{$fa-version}') format('truetype'),
    font-url('#{$fa-font-path}/fontawesome-webfont.svg?v=#{$fa-version}#fontawesomeregular') format('svg');
  font-weight: normal;
  font-style: normal;

And the following works:

@font-face {
  font-family: 'FontAwesome';
  src: font-url('fontawesome-webfont.eot?v=#{$fa-version}');
  src: font-url('fontawesome-webfont.eot?#iefix&v=#{$fa-version}') format('embedded-opentype'),
    font-url('fontawesome-webfont.woff2?v=#{$fa-version}') format('woff2'),
    font-url('fontawesome-webfont.woff?v=#{$fa-version}') format('woff'),
    font-url('fontawesome-webfont.ttf?v=#{$fa-version}') format('truetype'),
    font-url('fontawesome-webfont.svg?v=#{$fa-version}#fontawesomeregular') format('svg');
  font-weight: normal;
  font-style: normal;

An alternative would be to simply remove the forward slash following the interpolated $fa-font-path and then define $fa-font-path as an empty string or subdirectory with trailing forward slash (as needed).

Remember to recompile assets and restart your server as needed. For example, on a passenger setup:

prompt> rake assets:clean; rake assets:clobber
prompt> RAILS_ENV=production RAILS_GROUPS=assets rake assets:precompile
prompt> service passenger restart

Then reload your browser.

How to pass List<String> in post method using Spring MVC?

You can pass input as ["apple","orange"]if you want to leave the method as it is.

It worked for me with a similar method signature.

Installing OpenCV on Windows 7 for Python 2.7

I have posted an entry to setup OpenCV for Python in Windows:

Hope it helps.

SQL UPDATE SET one column to be equal to a value in a related table referenced by a different column?

    "QuestionID" = (SELECT "QuestionID" FROM "Answers" WHERE "AnswerID"="QuestionTrackings"."AnswerID")
    "QuestionID" is NULL
AND ...

Scrollbar without fixed height/Dynamic height with scrollbar

Flexbox is a modern alternative that lets you do this without fixed heights or JavaScript.

Setting display: flex; flex-direction: column; on the container and flex-shrink: 0; on the header and footer divs does the trick:


<div id="body">
    <div id="head">
        <p>Dynamic size without scrollbar</p>
        <p>Dynamic size without scrollbar</p>
        <p>Dynamic size without scrollbar</p>  
    <div id="content">
        <p>Dynamic size with scrollbar</p>
        <p>Dynamic size with scrollbar</p>
        <p>Dynamic size with scrollbar</p>
        <p>Dynamic size with scrollbar</p>
        <p>Dynamic size with scrollbar</p>
        <p>Dynamic size with scrollbar</p>
        <p>Dynamic size with scrollbar</p>
        <p>Dynamic size with scrollbar</p>
        <p>Dynamic size with scrollbar</p>
        <p>Dynamic size with scrollbar</p>
        <p>Dynamic size with scrollbar</p>
        <p>Dynamic size with scrollbar</p>
        <p>Dynamic size with scrollbar</p>
        <p>Dynamic size with scrollbar</p>
        <p>Dynamic size with scrollbar</p>
        <p>Dynamic size with scrollbar</p>
        <p>Dynamic size with scrollbar</p>
        <p>Dynamic size with scrollbar</p>
        <p>Dynamic size with scrollbar</p>
        <p>Dynamic size with scrollbar</p>
        <p>Dynamic size with scrollbar</p>
        <p>Dynamic size with scrollbar</p>
        <p>Dynamic size with scrollbar</p>
    <div id="foot">
        <p>Fixed size without scrollbar</p>
        <p>Fixed size without scrollbar</p>


#body {
    position: absolute;
    top: 150px;
    left: 150px;
    height: 300px;
    width: 500px;
    border: black dashed 2px;
    display: flex;
    flex-direction: column;

#head {
    border: green solid 1px;
    flex-shrink: 0;

    border: red solid 1px;
    overflow-y: auto;
    /*height: 100%;*/

#foot {
    border: blue solid 1px;
    height: 50px;
    flex-shrink: 0;

In a unix shell, how to get yesterday's date into a variable?

If you have Perl available (and your date doesn't have nice features like yesterday), you can use:

pax> date
Thu Aug 18 19:29:49 XYZ 2010

pax> dt=$(perl -e 'use POSIX;print strftime "%d/%m/%Y%",localtime time-86400;')

pax> echo $dt

What is the copy-and-swap idiom?

There are some good answers already. I'll focus mainly on what I think they lack - an explanation of the "cons" with the copy-and-swap idiom....

What is the copy-and-swap idiom?

A way of implementing the assignment operator in terms of a swap function:

X& operator=(X rhs)
    return *this;

The fundamental idea is that:

  • the most error-prone part of assigning to an object is ensuring any resources the new state needs are acquired (e.g. memory, descriptors)

  • that acquisition can be attempted before modifying the current state of the object (i.e. *this) if a copy of the new value is made, which is why rhs is accepted by value (i.e. copied) rather than by reference

  • swapping the state of the local copy rhs and *this is usually relatively easy to do without potential failure/exceptions, given the local copy doesn't need any particular state afterwards (just needs state fit for the destructor to run, much as for an object being moved from in >= C++11)

When should it be used? (Which problems does it solve [/create]?)

  • When you want the assigned-to objected unaffected by an assignment that throws an exception, assuming you have or can write a swap with strong exception guarantee, and ideally one that can't fail/throw..†

  • When you want a clean, easy to understand, robust way to define the assignment operator in terms of (simpler) copy constructor, swap and destructor functions.

    • Self-assignment done as a copy-and-swap avoids oft-overlooked edge cases.‡

  • When any performance penalty or momentarily higher resource usage created by having an extra temporary object during the assignment is not important to your application. ?

swap throwing: it's generally possible to reliably swap data members that the objects track by pointer, but non-pointer data members that don't have a throw-free swap, or for which swapping has to be implemented as X tmp = lhs; lhs = rhs; rhs = tmp; and copy-construction or assignment may throw, still have the potential to fail leaving some data members swapped and others not. This potential applies even to C++03 std::string's as James comments on another answer:

@wilhelmtell: In C++03, there is no mention of exceptions potentially thrown by std::string::swap (which is called by std::swap). In C++0x, std::string::swap is noexcept and must not throw exceptions. – James McNellis Dec 22 '10 at 15:24

‡ assignment operator implementation that seems sane when assigning from a distinct object can easily fail for self-assignment. While it might seem unimaginable that client code would even attempt self-assignment, it can happen relatively easily during algo operations on containers, with x = f(x); code where f is (perhaps only for some #ifdef branches) a macro ala #define f(x) x or a function returning a reference to x, or even (likely inefficient but concise) code like x = c1 ? x * 2 : c2 ? x / 2 : x;). For example:

struct X
    T* p_;
    size_t size_;
    X& operator=(const X& rhs)
        delete[] p_;  // OUCH!
        p_ = new T[size_ = rhs.size_];
        std::copy(p_, rhs.p_, rhs.p_ + rhs.size_);

On self-assignment, the above code delete's x.p_;, points p_ at a newly allocated heap region, then attempts to read the uninitialised data therein (Undefined Behaviour), if that doesn't do anything too weird, copy attempts a self-assignment to every just-destructed 'T'!

? The copy-and-swap idiom can introduce inefficiencies or limitations due to the use of an extra temporary (when the operator's parameter is copy-constructed):

struct Client
    IP_Address ip_address_;
    int socket_;
    X(const X& rhs)
      : ip_address_(rhs.ip_address_), socket_(connect(rhs.ip_address_))
    { }

Here, a hand-written Client::operator= might check if *this is already connected to the same server as rhs (perhaps sending a "reset" code if useful), whereas the copy-and-swap approach would invoke the copy-constructor which would likely be written to open a distinct socket connection then close the original one. Not only could that mean a remote network interaction instead of a simple in-process variable copy, it could run afoul of client or server limits on socket resources or connections. (Of course this class has a pretty horrid interface, but that's another matter ;-P).

What is the purpose of meshgrid in Python / NumPy?

Short answer

The purpose of meshgrid is to help remplace Python loops (slow interpreted code) by vectorized operations within C NumPy library.

Borrowed from this site.

enter image description here

x = np.arange(-4, 4, 0.25)
y = np.arange(-4, 4, 0.25)
X, Y = np.meshgrid(x, y)
R = np.sqrt(X**2 + Y**2)
Z = np.sin(R)

meshgrid is used to create pairs of coordinates between -4 and +4 with .25 increments in each direction X and Y. Each pair is then used to find R, and Z from it. This way of preparing "a grid" of coordinates is frequently used in plotting 3D surfaces, or coloring 2D surfaces.

Details: Python for-loop vs NumPy vector operation

To take a more simple example, let's say we have two sequences of values,

a = [2,7,9,20]    
b = [1,6,7,9]    ?

and we want to perform an operation on each possible pair of values, one taken from the first list, one taken from the second list. We also want to store the result. For example, let's say we want to get the sum of the values for each possible pair.

Slow and laborious method

c = []    
for i in range(len(b)):    
    row = []    
    for j in range(len(a)):    
        row.append (a[j] + b[i])
    c.append (row)    
print (c)


[[3, 8, 10, 21],
 [8, 13, 15, 26],
 [9, 14, 16, 27],
 [11, 16, 18, 29]]

Python is interpreted, these loops are relatively slow to execute.

Fast and easy method

meshgrid is intended to remove the loops from the code. It returns two arrays (i and j below) which can be combined to scan all the existing pairs like this:

i,j = np.meshgrid (a,b)    
c = i + j    
print (c)


[[ 3  8 10 21]
 [ 8 13 15 26]
 [ 9 14 16 27]
 [11 16 18 29]]

Meshgrid under the hood

The two arrays prepared by meshgrid are:

(array([[ 2,  7,  9, 20],
        [ 2,  7,  9, 20],
        [ 2,  7,  9, 20],
        [ 2,  7,  9, 20]]),

 array([[1, 1, 1, 1],
        [6, 6, 6, 6],
        [7, 7, 7, 7],
        [9, 9, 9, 9]]))

These arrays are created by repeating the values provided. One contains the values in identical rows, the other contains the other values in identical columns. The number of rows and column is determined by the number of elements in the other sequence.

The two arrays created by meshgrid are therefore shape compatible for a vector operation. Imagine x and y sequences in the code at the top of page having a different number of elements, X and Y resulting arrays will be shape compatible anyway, not requiring any broadcast.


numpy.meshgrid comes from MATLAB, like many other NumPy functions. So you can also study the examples from MATLAB to see meshgrid in use, the code for the 3D plotting looks the same in MATLAB.

What is a faster alternative to Python's http.server (or SimpleHTTPServer)?

If you have PHP installed you could use the builtin server.

php -S 0:8080

import dat file into R

The dat file has some lines of extra information before the actual data. Skip them with the skip argument:

           header=TRUE, skip=3)

An easy way to check this if you are unfamiliar with the dataset is to first use readLines to check a few lines, as below:

# [1] "Ozone data from CZ03 2009"   "Local time: GMT + 0"        
# [3] ""                            "Date        Hour      Value"
# [5] "01.01.2009 00:00       34.3" "01.01.2009 01:00       31.9"
# [7] "01.01.2009 02:00       29.9" "01.01.2009 03:00       28.5"
# [9] "01.01.2009 04:00       32.9" "01.01.2009 05:00       20.5"

Here, we can see that the actual data starts at [4], so we know to skip the first three lines.


If you really only wanted the Value column, you could do that by:

               header=TRUE, skip=3)$Value)

Again, readLines is useful for helping us figure out the actual name of the columns we will be importing.

But I don't see much advantage to doing that over reading the whole dataset in and extracting later.

numpy max vs amax vs maximum

You've already stated why np.maximum is different - it returns an array that is the element-wise maximum between two arrays.

As for np.amax and np.max: they both call the same function - np.max is just an alias for np.amax, and they compute the maximum of all elements in an array, or along an axis of an array.

In [1]: import numpy as np

In [2]: np.amax
Out[2]: <function numpy.core.fromnumeric.amax>

In [3]: np.max
Out[3]: <function numpy.core.fromnumeric.amax>

CSS3 Fade Effect

It's possible, use the structure below:



Where the <li> contains an <a> anchor tag that contains a span as shown above. Then insert the following css:

  • LI get position: relative;
  • Give <a> tag a height, width
  • Set <span> width & height to 100%, so that both <a> and <span> have same dimensions
  • Both <a> and <span> get position: relative;.
  • Assign the same background image to each element
  • <a> tag will have the 'OFF' background-position, and the <span> will have the 'ON' background-poisiton.
  • For 'OFF' state use opacity 0 for <span>
  • For 'ON' :hover state use opacity 1 for <span>
  • Set the -webkit or -moz transition on the <span> element

You'll have the ability to use the transition effect while still defaulting to the old background-position swap. Don't forget to insert IE alpha filter.

What methods of ‘clearfix’ can I use?

I always use the micro-clearfix :

.cf:after {
    content: " ";
    display: table;

.cf:after {
    clear: both;

 * For IE 6/7 only
.cf {
    *zoom: 1;

In Cascade Framework I even apply it by default on block level elements. IMO, applying it by default on block level elements gives block level elements more intuitive behavior than their traditonal behavior. It also made it a lot easier for me to add support for older browsers to Cascade Framework (which supports IE6-8 as well as modern browsers).

What's the difference between Apache's Mesos and Google's Kubernetes

Mesos and Kubernetes can both be used to manage a cluster of machines and abstract away the hardware.

Mesos, by design, doesn't provide you with a scheduler (to decide where and when to run processes and what to do if the process fails), you can use something like Marathon or Chronos, or write your own.

Kubernetes will do scheduling for you out of the box, and can be used as a scheduler for Mesos (please correct me if I'm wrong here!) which is where you can use them together. Mesos can have multiple schedulers sharing the same cluster, so in theory you could run kubernetes and chronos together on the same hardware.

Super simplistically: if you want control over how your containers are scheduled, go for Mesos, otherwise Kubernetes rocks.

How to make a TextBox accept only alphabetic characters?

        if (System.Text.RegularExpressions.Regex.IsMatch(textBox1.Text, "^[a-zA-Z]+$"))
            textBox1.Text = textBox1.Text.Remove(textBox1.Text.Length - 1);
            MessageBox.Show("Enter only Alphabets");


Please Try this

Setting an image for a UIButton in code

Don't worry so much framing the button from code, you can do that on the storyboard. This worked for me, one line...more simple.

[self.button setBackgroundImage:[UIImage imageNamed: @"yourPic.png"] forState:UIControlStateNormal];

Room persistance library. Delete all

You can create a DAO method to do this.

interface MyDao {
    @Query("DELETE FROM myTableName")
    public void nukeTable();

How do I add a bullet symbol in TextView?

With Unicode we can do it easily,but if want to change color of bullet, I tried with colored bullet image and set it as drawable left and it worked

    android:text="Hello bullet"
    android:drawableLeft="@drawable/bulleticon" >

Can't open config file: /usr/local/ssl/openssl.cnf on Windows

Not sure what is the difference between .cfg & .cnf In my server I couldn't find .cfg or .cnf I had created a new file for the same and placed it in the following folder /usr/local/ssl/bin

executed the

.\openssl genrsa -des3 -out <key name>.key 2048 

went great..

How to get the currently logged in user's user id in Django?

Assuming you are referring to Django's Auth User, in your view:

def game(request):
  user = request.user

  gta = Game.objects.create(name="gta", owner=user)

Find the IP address of the client in an SSH session

Simplest command to get the last 10 users logged in to the machine is last|head. To get all the users, simply use last command

Sanitizing user input before adding it to the DOM in Javascript

You could use a simple regular expression to assert that the id only contains allowed characters, like so:

    //The id is fine
    //The id is illegal

My example allows only alphanumerical characters, and strings of length 1 to 16, you should change it to match the type of ids that you use.

By the way, at line 6, the value property is missing a pair of quotes, an easy mistake to make when you quote on two levels.

I can't see your actual data flow, depending on context this check may not at all be needed, or it may not be enough. In order to make a proper security review we would need more information.

In general, about built in escape or sanitize functions, don't trust them blindly. You need to know exactly what they do, and you need to establish that that is actually what you need. If it is not what you need, the code your own, most of the time a simple whitelisting regex like the one I gave you works just fine.

How do I set the default page of my application in IIS7?

I was trying do the same of making a particular file my default page, instead of directory structure. So in IIS server I had to go to Default Document, add the page that I want to make as default and at the same time, go to the Web.config file and update the defaultDocument header with "enabled=true". This worked for me. Hopefully it helps.

Specify the date format in XMLGregorianCalendar

Yeah Got it...

Date dob=null;
DateFormat df=new SimpleDateFormat("dd/MM/yyyy");
dob=df.parse( "13/06/1983" );
GregorianCalendar cal = new GregorianCalendar();
XMLGregorianCalendar xmlDate = DatatypeFactory.newInstance().newXMLGregorianCalendarDate(cal.get(Calendar.YEAR), cal.get(Calendar.MONTH)+1, cal.get(Calendar.DAY_OF_MONTH), DatatypeConstants.FIELD_UNDEFINED);

This will give it in correct format.

How to equalize the scales of x-axis and y-axis in Python matplotlib?

See the documentation on plt.axis(). This:


doesn't work because it changes the limits of the axis to make circles appear circular. What you want is:


This creates a square plot with equal axes.

How to send Request payload to REST API in java?

The following code works for me.

//escape the double quotes in json string
String payload="{\"jsonrpc\":\"2.0\",\"method\":\"changeDetail\",\"params\":[{\"id\":11376}],\"id\":2}";
String requestUrl="";
sendPostRequest(requestUrl, payload);

method implementation:

public static String sendPostRequest(String requestUrl, String payload) {
    try {
        URL url = new URL(requestUrl);
        HttpURLConnection connection = (HttpURLConnection) url.openConnection();

        connection.setRequestProperty("Accept", "application/json");
        connection.setRequestProperty("Content-Type", "application/json; charset=UTF-8");
        OutputStreamWriter writer = new OutputStreamWriter(connection.getOutputStream(), "UTF-8");
        BufferedReader br = new BufferedReader(new InputStreamReader(connection.getInputStream()));
        StringBuffer jsonString = new StringBuffer();
        String line;
        while ((line = br.readLine()) != null) {
        return jsonString.toString();
    } catch (Exception e) {
            throw new RuntimeException(e.getMessage());


Scrollable Menu with Bootstrap - Menu expanding its container when it should not

For CSS, I found that max height of 180 is better for mobile phones landscape 320 when showing browser chrome.

.scrollable-menu {
    height: auto;
    max-height: 180px;
    overflow-x: hidden;

Also, to add visible scrollbars, this CSS should do the trick:

.scrollable-menu::-webkit-scrollbar {
    -webkit-appearance: none;
    width: 4px;        
.scrollable-menu::-webkit-scrollbar-thumb {
    border-radius: 3px;
    background-color: lightgray;
    -webkit-box-shadow: 0 0 1px rgba(255,255,255,.75);        

The changes are reflected here:

How to construct a REST API that takes an array of id's for the resources

You can build a Rest API or a restful project using ASP.NET MVC and return data as a JSON. An example controller function would be:

        public JsonpResult GetUsers(string userIds)
           var values = JsonConvert.DeserializeObject<List<int>>(userIds);

            var users = _userRepository.GetAllUsersByIds(userIds);

            var collection = users.Select(user => new { id = user.Id, fullname = user.FirstName +" "+ user.LastName });
            var result = new { users = collection };

            return this.Jsonp(result);
        public IQueryable<User> GetAllUsersByIds(List<int> ids)
            return _db.Users.Where(c=> ids.Contains(c.Id));

Then you just call the GetUsers function via a regular AJAX function supplying the array of Ids(in this case I am using jQuery stringify to send the array as string and dematerialize it back in the controller but you can just send the array of ints and receive it as an array of int's in the controller). I've build an entire Restful API using ASP.NET MVC that returns the data as cross domain json and that can be used from any app. That of course if you can use ASP.NET MVC.

function GetUsers()
           var link = '<%= ResolveUrl("~")%>users?callback=?';
           var userIds = [];
            $('#multiselect :selected').each(function (i, selected) {
                userIds[i] = $(selected).val();

                url: link,
                traditional: true,
                data: { 'userIds': JSON.stringify(userIds) },
                dataType: "jsonp",
                jsonpCallback: "refreshUsers"

How to do a logical OR operation for integer comparison in shell scripting?

Sometimes you need to use double brackets, otherwise you get an error like too many arguments

if [[ $OUTMERGE == *"fatal"* ]] || [[ $OUTMERGE == *"Aborting"* ]]

OraOLEDB.Oracle provider is not registered on the local machine

I had the same issue using IIS.

Make sure the option 'Enable 32bit Applications' is set to true on Advanced Configuration of the Application Pool.

Is it possible to start activity through adb shell?

You can also find the name of the current on screen activity using

adb shell dumpsys window windows | grep 'mCurrentFocus'

List<Object> and List<?>

List is an interface so you can't instanciate it. Use any of its implementatons instead e.g.

List<Object> object = new List<Object>();

About List : you can use any object as a generic param for it instance:

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


List<?> list = new ArrayList<Integer>();

While using List<Object> this declaration is invalid because it will be type missmatch.

how to get javaScript event source element?

Try something like this:


    <script type="text/javascript">
        function doSomething(event) {
          var source = || event.srcElement;
          if(window.event) {
            // IE8 and earlier
            // doSomething
           } else if(e.which) {
            // IE9/Firefox/Chrome/Opera/Safari
            // doSomething

    <button onclick="doSomething('param')" id="id_button">


ASP.NET Web Application Message Box

You need to reference the namespace

using System.Windows.Form;

and then add in the code

protected void Button1_Click(object sender, EventArgs e)
        MessageBox.Show(" Hi....");


How to create a notification with NotificationCompat.Builder?

You can try this code this works fine for me:

    NotificationCompat.Builder mBuilder= new NotificationCompat.Builder(this);

    Intent i = new Intent(noti.this, Xyz_activtiy.class);
    PendingIntent pendingIntent= PendingIntent.getActivity(this,0,i,0);

    mBuilder.setContentTitle("New notification title");
    mBuilder.setContentText("Notification text");

    NotificationManager notificationManager= (NotificationManager)getSystemService(Context.NOTIFICATION_SERVICE);

How do I truly reset every setting in Visual Studio 2012?

To reset your settings

  • On the Tools menu, click Import and Export Settings.
  • On the Welcome to the Import and Export Settings Wizard page, click Reset all settings and then click Next.
  • If you want to delete your current settings combination, choose No, just reset settings, overwriting all current settings, and then click Next. Select the programming language(s) you want to reset the setting for.

Click Finish.

The Reset Complete page alerts you to any problems encountered during the reset.

Missing visible-** and hidden-** in Bootstrap v4

Unfortunately all classes hidden-*-up and hidden-*-down were removed from Bootstrap (as of Bootstrap Version 4 Beta, in Version 4 Alpha and Version 3 these classes still existed).

Instead, new classes d-* should be used, as mentioned here:

I found out that the new approach is less useful under some circumstances. The old approach was to HIDE elements while the new approach is to SHOW elements. Showing elements is not that easy with CSS since you need to know if the element is displayed as block, inline, inline-block, table etc.

You might want to restore the former "hidden-*" styles known from Bootstrap 3 with this CSS:

 * Restore Bootstrap 3 "hidden" utility classes.

/* Breakpoint XS */
@media (max-width: 575px)
    .hidden-xs-down, .hidden-sm-down, .hidden-md-down, .hidden-lg-down, .hidden-xl-down, 
    .hidden-unless-sm, .hidden-unless-md, .hidden-unless-lg, .hidden-unless-xl
        display: none !important;


/* Breakpoint SM */
@media (min-width: 576px) and (max-width: 767px)
    .hidden-sm-down, .hidden-md-down, .hidden-lg-down, .hidden-xl-down, 
    .hidden-xs-up, .hidden-sm-up, 
    .hidden-unless-xs, .hidden-unless-md, .hidden-unless-lg, .hidden-unless-xl
        display: none !important;

/* Breakpoint MD */
@media (min-width: 768px) and (max-width: 991px)
    .hidden-md-down, .hidden-lg-down, .hidden-xl-down, 
    .hidden-xs-up, .hidden-sm-up, .hidden-md-up, 
    .hidden-unless-xs, .hidden-unless-sm, .hidden-unless-lg, .hidden-unless-xl
        display: none !important;

/* Breakpoint LG */
@media (min-width: 992px) and (max-width: 1199px)
    .hidden-lg-down, .hidden-xl-down, 
    .hidden-xs-up, .hidden-sm-up, .hidden-md-up, .hidden-lg-up, 
    .hidden-unless-xs, .hidden-unless-sm, .hidden-unless-md, .hidden-unless-xl
        display: none !important;

/* Breakpoint XL */
@media (min-width: 1200px)
    .hidden-xs-up, .hidden-sm-up, .hidden-md-up, .hidden-lg-up, .hidden-xl-up, 
    .hidden-unless-xs, .hidden-unless-sm, .hidden-unless-md, .hidden-unless-lg
        display: none !important;

The classes hidden-unless-* were not included in Bootstrap 3, but they are useful as well and should be self-explanatory.

Writing List of Strings to Excel CSV File in Python

I know I'm a little late, but something I found that works (and doesn't require using csv) is to write a for loop that writes to your file for every element in your list.

# Define Data
RESULTS = ['apple','cherry','orange','pineapple','strawberry']

# Open File
resultFyle = open("output.csv",'w')

# Write data to file
for r in RESULTS:
    resultFyle.write(r + "\n")

I don't know if this solution is any better than the ones already offered, but it more closely reflects your original logic so I thought I'd share.

In Java, how to append a string more efficiently?

You should use the StringBuilder class.

StringBuilder stringBuilder = new StringBuilder();

stringBuilder.append("Some text");
stringBuilder.append("Some text");
stringBuilder.append("Some text");

String finalString = stringBuilder.toString();

In addition, please visit:

How do I search for files in Visual Studio Code?

To search for specifil file types in visual studio code.
Type ctrl+p and then search for something like *.py.
Simple and easy

Printing Java Collections Nicely (toString Doesn't Return Pretty Output)

Implement toString() on the class.

I recommend the Apache Commons ToStringBuilder to make this easier. With it, you just have to write this sort of method:

public String toString() {
     return new ToStringBuilder(this).
       append("name", name).
       append("age", age).

In order to get this sort of output:


There is also a reflective implementation.

Is it possible to get element from HashMap by its position?

If you, for some reason, have to stick with the hashMap, you can convert the keySet to an array and index the keys in the array to get the values in the map like so:

Object[] keys = map.keySet().toArray();

You can then access the map like:


How do check if a PHP session is empty?

Use isset, empty or array_key_exists (especially for array keys) before accessing a variable whose existence you are not sure of. So change the order in your second example:

if (!isset($_SESSION['something']) || $_SESSION['something'] == '')

MySQL case sensitive query

Whilst the listed answer is correct, may I suggest that if your column is to hold case sensitive strings you read the documentation and alter your table definition accordingly.

In my case this amounted to defining my column as:

`tag` varchar(255) CHARACTER SET utf8 COLLATE utf8_bin NOT NULL DEFAULT ''

This is in my opinion preferential to adjusting your queries.

How to output numbers with leading zeros in JavaScript?

NOTE: Potentially outdated. ECMAScript 2017 includes String.prototype.padStart.

You'll have to convert the number to a string since numbers don't make sense with leading zeros. Something like this:

function pad(num, size) {
    num = num.toString();
    while (num.length < size) num = "0" + num;
    return num;

Or, if you know you'd never be using more than X number of zeros, this might be better. This assumes you'd never want more than 10 digits.

function pad(num, size) {
    var s = "000000000" + num;
    return s.substr(s.length-size);

If you care about negative numbers you'll have to strip the - and read it.

avrdude: stk500v2_ReceiveMessage(): timeout

The error message basically means that the programmer is unable to contact the bootloader on the device; the code you're trying to upload has no bearing on the problem.

What causes this can be numerous and varied, some possible issues:

  1. UART communications

    • Blinking is happening, so hopefully you aren't using the wrong port. It might be worth checking again though, sometimes USB COM devices install on strange port numbers.

    • Connect TX to RX (and disconnect them from the AVR if possible) then open a terminal on the COM port, you should see characters echoed if you type them. If you don't, something is wrong up-stream of the chip, it could be the communications chip (I think the Arduino 2560 uses a secondary AVR instead of an FTDI for some reason, so that could be broken, either its software or hardware)

  2. ATmega* bootloader

    • The AVR is not executing the bootloader for some reason. If the programmer is not resetting the micro before attempting to connect, this might be the reason. Try to reset the AVR (press and release the button) while the programmer is attempting to connect. Sometimes software that runs in a tight loop will prevent the bootloader from connecting.

    • Barring that, the fuses might have gotten messed up or the code erased. You would need to reflash the bootloader and proper fuses, again, see the appropriate info page for your device.

  3. Arduino Mega 2560 only: ATmega8U/16U software

    • Might not be working and would need reprogramming. See the Programming section on the info page, you will need the firmware and Atmel-compatible DFU (device firmware update) software on your computer to reflash the target.
  4. Hardware damage to the board, AVR(s), or FTDI chip

    • You're hosed; need a new chip.

Check this forum post for some more ideas.

Truncating Text in PHP?

$mystring = "this is the text I would like to truncate";

// Pass your variable to the function
$mystring = truncate($mystring);

// Truncated tring printed out;
echo $mystring;

//truncate text function
public function truncate($text) {

    //specify number fo characters to shorten by
    $chars = 25;

    $text = $text." ";
    $text = substr($text,0,$chars);
    $text = substr($text,0,strrpos($text,' '));
    $text = $text."...";
    return $text;

ActiveRecord find and only return selected columns

My answer comes quite late because I'm a pretty new developer. This is what you can do:, :website, :city).find(

Btw, this is Rails 4

Assignment makes pointer from integer without cast

As others already noted, in one case you are attempting to return cString (which is a char * value in this context - a pointer) from a function that is declared to return a char (which is an integer). In another case you do the reverse: you are assigning a char return value to a char * pointer. This is what triggers the warnings. You certainly need to declare your return values as char *, not as char.

Note BTW that these assignments are in fact constraint violations from the language point of view (i.e. they are "errors"), since it is illegal to mix pointers and integers in C like that (aside from integral constant zero). Your compiler is simply too forgiving in this regard and reports these violations as mere "warnings".

What I also wanted to note is that in several answers you might notice the relatively strange suggestion to return void from your functions, since you are modifying the string in-place. While it will certainly work (since you indeed are modifying the string in-place), there's nothing really wrong with returning the same value from the function. In fact, it is a rather standard practice in C language where applicable (take a look at the standard functions like strcpy and others), since it enables "chaining" of function calls if you choose to use it, and costs virtually nothing if you don't use "chaining".

That said, the assignments in your implementation of compareString look complete superfluous to me (even though they won't break anything). I'd either get rid of them

int compareString(char cString1[], char cString2[]) { 
    // To lowercase 

    // Do regular strcmp 
    return strcmp(cString1, cString2); 

or use "chaining" and do

int compareString(char cString1[], char cString2[]) { 
    return strcmp(strToLower(cString1), strToLower(cString2)); 

(this is when your char * return would come handy). Just keep in mind that such "chained" function calls are sometimes difficult to debug with a step-by-step debugger.

As an additional, unrealted note, I'd say that implementing a string comparison function in such a destructive fashion (it modifies the input strings) might not be the best idea. A non-destructive function would be of a much greater value in my opinion. Instead of performing as explicit conversion of the input strings to a lower case, it is usually a better idea to implement a custom char-by-char case-insensitive string comparison function and use it instead of calling the standard strcmp.

How to insert multiple rows from array using CodeIgniter framework?

Assembling one INSERT statement with multiple rows is much faster in MySQL than one INSERT statement per row.

That said, it sounds like you might be running into string-handling problems in PHP, which is really an algorithm problem, not a language one. Basically, when working with large strings, you want to minimize unnecessary copying. Primarily, this means you want to avoid concatenation. The fastest and most memory efficient way to build a large string, such as for inserting hundreds of rows at one, is to take advantage of the implode() function and array assignment.

$sql = array(); 
foreach( $data as $row ) {
    $sql[] = '("'.mysql_real_escape_string($row['text']).'", '.$row['category_id'].')';
mysql_query('INSERT INTO table (text, category) VALUES '.implode(',', $sql));

The advantage of this approach is that you don't copy and re-copy the SQL statement you've so far assembled with each concatenation; instead, PHP does this once in the implode() statement. This is a big win.

If you have lots of columns to put together, and one or more are very long, you could also build an inner loop to do the same thing and use implode() to assign the values clause to the outer array.

Access to the path is denied

In my case, I'm trying to access a file that is set to be read-only

enter image description here

And I solved it by disabling read-only and I got it fixed!

enter image description here

Hope it can be helpful for someone experiencing a situation like me.

Check if multiple strings exist in another string

Just to add some diversity with regex:

import re

if any(re.findall(r'a|b|c', str, re.IGNORECASE)):
    print 'possible matches thanks to regex'
    print 'no matches'

or if your list is too long - any(re.findall(r'|'.join(a), str, re.IGNORECASE))

Resync git repo with new .gitignore file

The solution mentioned in ".gitignore file not ignoring" is a bit extreme, but should work:

# rm all files
git rm -r --cached .
# add all files as per new .gitignore
git add .
# now, commit for new .gitignore to apply
git commit -m ".gitignore is now working"

(make sure to commit first your changes you want to keep, to avoid any incident as jball037 comments below.
The --cached option will keep your files untouched on your disk though.)

You also have other more fine-grained solution in the blog post "Making Git ignore already-tracked files":

git rm --cached `git ls-files -i --exclude-standard`

Bassim suggests in his edit:

Files with space in their paths

In case you get an error message like fatal: path spec '...' did not match any files, there might be files with spaces in their path.

You can remove all other files with option --ignore-unmatch:

git rm --cached --ignore-unmatch `git ls-files -i --exclude-standard`

but unmatched files will remain in your repository and will have to be removed explicitly by enclosing their path with double quotes:

git rm --cached "<>"

Where is the Global.asax.cs file?

It don't create normally; you need to add it by yourself.

After adding Global.asax by

  • Right clicking your website -> Add New Item -> Global Application Class -> Add

You need to add a class

  • Right clicking App_Code -> Add New Item -> Class -> name it Global.cs -> Add

Inherit the newly generated by System.Web.HttpApplication and copy all the method created Global.asax to Global.cs and also add an inherit attribute to the Global.asax file.

Your Global.asax will look like this: -

<%@ Application Language="C#" Inherits="Global" %>

Your Global.cs in App_Code will look like this: -

public class Global : System.Web.HttpApplication
    public Global()
        // TODO: Add constructor logic here

    void Application_Start(object sender, EventArgs e)
        // Code that runs on application startup

    /// Many other events like begin request...e.t.c, e.t.c

Mipmap drawables for icons

It seems Google have updated their docs since all these answers, so hopefully this will help someone else in future :) Just came across this question myself, while creating a new (new new) project.

TL;DR: drawables may be stripped out as part of dp-specific resource optimisation. Mipmaps will not be stripped.

Different home screen launcher apps on different devices show app launcher icons at various resolutions. When app resource optimization techniques remove resources for unused screen densities, launcher icons can wind up looking fuzzy because the launcher app has to upscale a lower-resolution icon for display. To avoid these display issues, apps should use the mipmap/ resource folders for launcher icons. The Android system preserves these resources regardless of density stripping, and ensures that launcher apps can pick icons with the best resolution for display.


Use JSTL forEach loop's varStatus as an ID

The variable set by varStatus is a LoopTagStatus object, not an int. Use:

<div id="divIDNo${theCount.index}">

To clarify:

  • ${theCount.index} starts counting at 0 unless you've set the begin attribute
  • ${theCount.count} starts counting at 1

How to check iOS version?

  1. From the the Home Screen, tap Settings > General > About.
  2. The software version of your device should appear on this screen.
  3. Check whether the version number is greater than 3.1.3.

Making an image act like a button

You could implement a JavaScript block which contains a function with your needs.

<div style="position: absolute; left: 10px; top: 40px;"> 
    <img src="logg.png" width="114" height="38" onclick="DoSomething();" />

Better way to convert file sizes in Python

Instead of a size divisor of 1024 * 1024 you could use the << bitwise shifting operator, i.e. 1<<20 to get megabytes, 1<<30 to get gigabytes, etc.

In the simplest scenario you can have e.g. a constant MBFACTOR = float(1<<20) which can then be used with bytes, i.e.: megas = size_in_bytes/MBFACTOR.

Megabytes are usually all that you need, or otherwise something like this can be used:

# bytes pretty-printing
    (1<<50, ' PB'),
    (1<<40, ' TB'),
    (1<<30, ' GB'),
    (1<<20, ' MB'),
    (1<<10, ' KB'),
    (1, (' byte', ' bytes')),

def pretty_size(bytes, units=UNITS_MAPPING):
    """Get human-readable file sizes.
    simplified version of
    for factor, suffix in units:
        if bytes >= factor:
    amount = int(bytes / factor)

    if isinstance(suffix, tuple):
        singular, multiple = suffix
        if amount == 1:
            suffix = singular
            suffix = multiple
    return str(amount) + suffix


## [Out] ###########################
1 byte
42 bytes
4 KB
227 MB
311 GB
88 TB
2 PB

How do I create a new class in IntelliJ without using the mouse?

With Esc and Command + 1 you can navigate between project view and editor area - back and forward, in this way you can select the folder/location you need

With Control +Option + N you can trigger New file menu and select whatever you need, class, interface, file, etc. This works in editor as well in project view and it relates to the current selected location

// please consider that this is working with standard key mapping

Checking whether a variable is an integer or not

Testing, if object is a string (works with Python 2.* and Python 3.* )

text = get_text()

    text = text+""
    return "Not a string"


SQL to find the number of distinct values in a column

An sql sum of column_name's unique values and sorted by the frequency:

SELECT column_name, COUNT(*) FROM table_name GROUP BY column_name ORDER BY 2 DESC;

C: scanf to array

The %d conversion specifier will only convert one decimal integer. It doesn't know that you're passing an array, it can't modify its behavior based on that. The conversion specifier specifies the conversion.

There is no specifier for arrays, you have to do it explicitly. Here's an example with four conversions:

if(scanf("%d %d %d %d", &array[0], &array[1], &array[2], &array[3]) == 4)
  printf("got four numbers\n");

Note that this requires whitespace between the input numbers.

If the id is a single 11-digit number, it's best to treat as a string:

char id[12];

if(scanf("%11s", id) == 1)
  /* inspect the *character* in id[0], compare with '1' or '2' for instance. */

Setting the height of a SELECT in IE

Even though setting a CSS height value to the select element does not work, the padding attribute works alright. Setting a top and bottom padding will make your select element look taller.

SQL query for a carriage return in a string and ultimately removing carriage return

In SQL Server I would use:

WHERE CHARINDEX(CHAR(13), name) <> 0 OR CHARINDEX(CHAR(10), name) <> 0

This will search for both carriage returns and line feeds.

If you want to search for tabs too just add:

OR CHARINDEX(CHAR(9), name) <> 0

Read an Excel file directly from a R script

Another solution is the xlsReadWrite package, which doesn't require additional installs but does require you download the additional shlib before you use it the first time by :


Forgetting this can cause utter frustration. Been there and all that...

On a sidenote : You might want to consider converting to a text-based format (eg csv) and read in from there. This for a number of reasons :

  • whatever your solution (RODBC, gdata, xlsReadWrite) some strange things can happen when your data gets converted. Especially dates can be rather cumbersome. The HFWutils package has some tools to deal with EXCEL dates (per @Ben Bolker's comment).

  • if you have large sheets, reading in text files is faster than reading in from EXCEL.

  • for .xls and .xlsx files, different solutions might be necessary. EG the xlsReadWrite package currently does not support .xlsx AFAIK. gdata requires you to install additional perl libraries for .xlsx support. xlsx package can handle extensions of the same name.

How do I remove blank elements from an array?

There are already a lot of answers but here is another approach if you're in the Rails world:

 cities = ["Kathmandu", "Pokhara", "", "Dharan", "Butwal"].select &:present?

Inline comments for Bash?

My preferred is:

Commenting in a Bash script

This will have some overhead, but technically it does answer your question

echo abc `#put your comment here` \
     def `#another chance for a comment` \
     xyz etc

And for pipelines specifically, there is a cleaner solution with no overhead

echo abc |        # normal comment OK here
     tr a-z A-Z | # another normal comment OK here
     sort |       # the pipelines are automatically continued
     uniq         # final comment

How to put a line comment for a multi-line command

Change the project theme in Android Studio?

Note : This answer is now out-of-date. This changes the theme in "preview" only as @imjohnking and @john-ktejik pointed out. As @Shahzeb mentioned, theme can modified in res>values>styles

Android Studio 0.8.2 provides a slightly easier way to change the theme. In the preview window, you can select the theme of "Holo.Light.DarkActionBar" by clicking on the theme combo box just above the phone.enter image description here

Or do a ctrl + click on the @style/AppTheme in the Android manifest file. It will open styles.xml file where you can change the parent attribute of the style tag.

  • Theme.Holo for a "dark" theme.
  • Theme.Holo.Light for a "light" theme.

When using the Support Library, you must instead use the Theme.AppCompat themes:

  • Theme.AppCompat for the "dark" theme.
  • Theme.AppCompat.Light for the "light" theme.
  • Theme.AppCompat.Light.DarkActionBar for the light theme with a dark action bar.


How do I create my own URL protocol? (e.g. so://...)

Open notepad and paste the code below into it. Change "YourApp" into your app's name. Save it to YourApp.reg and execute it by clicking on it in explorer. That's it! Cheers! Erwin Haantjes


@="URL:YourApp Protocol"
"URL Protocol"=""

@="\"C:\\Program Files\\YourApp\\YourApp.exe\""



@="\"C:\\Program Files\\YourApp\\YourApp.exe\" \"%1\" \"%2\" \"%3\" \"%4\" \"%5\" \"%6\" \"%7\" \"%8\" \"%9\""

AngularJS: How to clear query parameters in the URL?

To remove ALL query parameters, do:


To remove ONE particular query parameter, do:

$'myQueryParam', null);

C# : assign data to properties via constructor vs. instantiating

Object initializers are cool because they allow you to set up a class inline. The tradeoff is that your class cannot be immutable. Consider:

public class Album 
    // Note that we make the setter 'private'
    public string Name { get; private set; }
    public string Artist { get; private set; }
    public int Year { get; private set; }

    public Album(string name, string artist, int year)
        this.Name = name;
        this.Artist = artist;
        this.Year = year;

If the class is defined this way, it means that there isn't really an easy way to modify the contents of the class after it has been constructed. Immutability has benefits. When something is immutable, it is MUCH easier to determine that it's correct. After all, if it can't be modified after construction, then there is no way for it to ever be 'wrong' (once you've determined that it's structure is correct). When you create anonymous classes, such as:

new { 
    Name = "Some Name",
    Artist = "Some Artist",
    Year = 1994

the compiler will automatically create an immutable class (that is, anonymous classes cannot be modified after construction), because immutability is just that useful. Most C++/Java style guides often encourage making members const(C++) or final (Java) for just this reason. Bigger applications are just much easier to verify when there are fewer moving parts.

That all being said, there are situations when you want to be able quickly modify the structure of your class. Let's say I have a tool that I want to set up:

public void Configure(ConfigurationSetup setup);

and I have a class that has a number of members such as:

class ConfigurationSetup {
    public String Name { get; set; }
    public String Location { get; set; }
    public Int32 Size { get; set; }
    public DateTime Time { get; set; }

    // ... and some other configuration stuff... 

Using object initializer syntax is useful when I want to configure some combination of properties, but not neccesarily all of them at once. For example if I just want to configure the Name and Location, I can just do:

ConfigurationSetup setup = new ConfigurationSetup {
    Name = "Some Name",
    Location = "San Jose"

and this allows me to set up some combination without having to define a new constructor for every possibly permutation.

On the whole, I would argue that making your classes immutable will save you a great deal of development time in the long run, but having object initializer syntax makes setting up certain configuration permutations much easier.

Selecting/excluding sets of columns in pandas

Another option, without dropping or filtering in a loop:

import numpy as np
import pandas as pd

# Create a dataframe with columns A,B,C and D
df = pd.DataFrame(np.random.randn(100, 4), columns=list('ABCD'))

# include the columns you want
df[df.columns[df.columns.isin(['A', 'B'])]]

# or more simply include columns:
df[['A', 'B']]

# exclude columns you don't want

# or even simpler since 0.24
# with the caveat that it reorders columns alphabetically 
df[df.columns.difference(['C', 'D'])]

What does ON [PRIMARY] mean?

To add a very important note on what Mark S. has mentioned in his post. In the specific SQL Script that has been mentioned in the question you can NEVER mention two different file groups for storing your data rows and the index data structure.

The reason why is due to the fact that the index being created in this case is a clustered Index on your primary key column. The clustered index data and the data rows of your table can NEVER be on different file groups.

So in case you have two file groups on your database e.g. PRIMARY and SECONDARY then below mentioned script will store your row data and clustered index data both on PRIMARY file group itself even though I've mentioned a different file group ([SECONDARY]) for the table data. More interestingly the script runs successfully as well (when I was expecting it to give an error as I had given two different file groups :P). SQL Server does the trick behind the scene silently and smartly.

CREATE TABLE [dbo].[be_Categories](
    [CategoryID] [uniqueidentifier] ROWGUIDCOL  NOT NULL CONSTRAINT [DF_be_Categories_CategoryID]  DEFAULT (newid()),
    [CategoryName] [nvarchar](50) NULL,
    [Description] [nvarchar](200) NULL,
    [ParentID] [uniqueidentifier] NULL,
    [CategoryID] ASC

NOTE: Your index can reside on a different file group ONLY if the index being created is non-clustered in nature.

The below script which creates a non-clustered index will get created on [SECONDARY] file group instead when the table data already resides on [PRIMARY] file group:

CREATE NONCLUSTERED INDEX [IX_Categories] ON [dbo].[be_Categories]
    [CategoryName] ASC

You can get more information on how storing non-clustered indexes on a different file group can help your queries perform better. Here is one such link.

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

I know this has several answers, but none of these really helped me. I found [this article][1] which explains why my sticky wasn't operating as expected.

Basically, you cannot use position: sticky; on <thead> or <tr> elements. However, they can be used on <th>.

The minimum code I needed to make it work is as follows:

table {
  text-align: left;
  position: relative;

th {
  background: white;
  position: sticky;
  top: 0;

With the table set to relative the <th> can be set to sticky, with the top at 0 [1]:

NOTE: It's necessary to wrap the table with a div with max-height:

<div id="managerTable" >


#managerTable {
    max-height: 500px;
    overflow: auto;

Display current date and time without punctuation

Here you go:

date +%Y%m%d%H%M%S

As man date says near the top, you can use the date command like this:

date [OPTION]... [+FORMAT]

That is, you can give it a format parameter, starting with a +. You can probably guess the meaning of the formatting symbols I used:

  • %Y is for year
  • %m is for month
  • %d is for day
  • ... and so on

You can find this, and other formatting symbols in man date.

Animate visibility modes, GONE and VISIBLE

You can use the expandable list view explained in API demos to show groups

To animate the list items motion, you will have to override the getView method and apply translate animation on each list item. The values for animation depend on the position of each list item. This was something which i tried on a simple list view long time back.

How to get number of rows using SqlDataReader in C#

There are only two options:

  • Find out by reading all rows (and then you might as well store them)

  • run a specialized SELECT COUNT(*) query beforehand.

Going twice through the DataReader loop is really expensive, you would have to re-execute the query.

And (thanks to Pete OHanlon) the second option is only concurrency-safe when you use a transaction with a Snapshot isolation level.

Since you want to end up storing all rows in memory anyway the only sensible option is to read all rows in a flexible storage (List<> or DataTable) and then copy the data to any format you want. The in-memory operation will always be much more efficient.

Create a directory if it does not exist and then create the files in that directory as well

Using java.nio.Path it would be quite simple -

public static Path createFileWithDir(String directory, String filename) {
        File dir = new File(directory);
        if (!dir.exists()) dir.mkdirs();
        return Paths.get(directory + File.separatorChar + filename);

Why is the default value of the string type null instead of an empty string?

Empty strings and nulls are fundamentally different. A null is an absence of a value and an empty string is a value that is empty.

The programming language making assumptions about the "value" of a variable, in this case an empty string, will be as good as initiazing the string with any other value that will not cause a null reference problem.

Also, if you pass the handle to that string variable to other parts of the application, then that code will have no ways of validating whether you have intentionally passed a blank value or you have forgotten to populate the value of that variable.

Another occasion where this would be a problem is when the string is a return value from some function. Since string is a reference type and can technically have a value as null and empty both, therefore the function can also technically return a null or empty (there is nothing to stop it from doing so). Now, since there are 2 notions of the "absence of a value", i.e an empty string and a null, all the code that consumes this function will have to do 2 checks. One for empty and the other for null.

In short, its always good to have only 1 representation for a single state. For a broader discussion on empty and nulls, see the links below.

NULL vs Empty when dealing with user input

How can I calculate the time between 2 Dates in typescript

It doesn't work because Date - Date relies on exactly the kind of type coercion TypeScript is designed to prevent.

There is a workaround this using the + prefix:

var t = - +(new Date("2013-02-20T12:01:04.753Z");

Or, if you prefer not to use

var t = +(new Date()) - +(new Date("2013-02-20T12:01:04.753Z"));

See discussion here.

Or see Siddharth Singh's answer, below, for a more elegant solution using valueOf()

turn typescript object into json string

Be careful when using these JSON.(parse/stringify) methods. I did the same with complex objects and it turned out that an embedded array with some more objects had the same values for all other entities in the object tree I was serializing.

const temp = [];
const t = {
    name: "name",
    etc: [
            a: 0,
for (let i = 0; i < 3; i++) {
    const bla = Object.assign({}, t); = + i;
    bla.etc[0].a = i;


Save file/open file dialog box, using Swing & Netbeans GUI editor

Here is an example

private void doOpenFile() {
    int result = myFileChooser.showOpenDialog(this);

    if (result == JFileChooser.APPROVE_OPTION) {
        Path path = myFileChooser.getSelectedFile().toPath();

        try {
            String contentString = "";

            for (String s : Files.readAllLines(path, StandardCharsets.UTF_8)) {
                contentString += s;


        } catch (IOException e) {
            // TODO Auto-generated catch block

private void doSaveFile() {
    int result = myFileChooser.showSaveDialog(this);

    if (result == JFileChooser.APPROVE_OPTION) {
        // We'll be making a mytmp.txt file, write in there, then move it to
        // the selected
        // file. This takes care of clearing that file, should there be
        // content in it.
        File targetFile = myFileChooser.getSelectedFile();

        try {
            if (!targetFile.exists()) {

            FileWriter fw = new FileWriter(targetFile);

        } catch (IOException e) {

Load view from an external xib file in storyboard

My full example is here, but I will provide a summary below.


Add a .swift and .xib file each with the same name to your project. The .xib file contains your custom view layout (using auto layout constraints preferably).

Make the swift file the xib file's owner.

enter image description here Code

Add the following code to the .swift file and hook up the outlets and actions from the .xib file.

import UIKit
class ResuableCustomView: UIView {

    let nibName = "ReusableCustomView"
    var contentView: UIView?

    @IBOutlet weak var label: UILabel!
    @IBAction func buttonTap(_ sender: UIButton) {
        label.text = "Hi"

    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)

        guard let view = loadViewFromNib() else { return }
        view.frame = self.bounds
        contentView = view

    func loadViewFromNib() -> UIView? {
        let bundle = Bundle(for: type(of: self))
        let nib = UINib(nibName: nibName, bundle: bundle)
        return nib.instantiate(withOwner: self, options: nil).first as? UIView

Use it

Use your custom view anywhere in your storyboard. Just add a UIView and set the class name to your custom class name.

enter image description here

For a while Christopher Swasey's approach was the best approach I had found. I asked a couple of the senior devs on my team about it and one of them had the perfect solution! It satisfies every one of the concerns that Christopher Swasey so eloquently addressed and it doesn't require boilerplate subclass code(my main concern with his approach). There is one gotcha, but other than that it is fairly intuitive and easy to implement.

  1. Create a custom UIView class in a .swift file to control your xib. i.e. MyCustomClass.swift
  2. Create a .xib file and style it as you want. i.e. MyCustomClass.xib
  3. Set the File's Owner of the .xib file to be your custom class (MyCustomClass)
  4. GOTCHA: leave the class value (under the identity Inspector) for your custom view in the .xib file blank. So your custom view will have no specified class, but it will have a specified File's Owner.
  5. Hook up your outlets as you normally would using the Assistant Editor.
    • NOTE: If you look at the Connections Inspector you will notice that your Referencing Outlets do not reference your custom class (i.e. MyCustomClass), but rather reference File's Owner. Since File's Owner is specified to be your custom class, the outlets will hook up and work propery.
  6. Make sure your custom class has @IBDesignable before the class statement.
  7. Make your custom class conform to the NibLoadable protocol referenced below.
    • NOTE: If your custom class .swift file name is different from your .xib file name, then set the nibName property to be the name of your .xib file.
  8. Implement required init?(coder aDecoder: NSCoder) and override init(frame: CGRect) to call setupFromNib() like the example below.
  9. Add a UIView to your desired storyboard and set the class to be your custom class name (i.e. MyCustomClass).
  10. Watch IBDesignable in action as it draws your .xib in the storyboard with all of it's awe and wonder.

Here is the protocol you will want to reference:

public protocol NibLoadable {
    static var nibName: String { get }

public extension NibLoadable where Self: UIView {

    public static var nibName: String {
        return String(describing: Self.self) // defaults to the name of the class implementing this protocol.

    public static var nib: UINib {
        let bundle = Bundle(for: Self.self)
        return UINib(nibName: Self.nibName, bundle: bundle)

    func setupFromNib() {
        guard let view = Self.nib.instantiate(withOwner: self, options: nil).first as? UIView else { fatalError("Error loading \(self) from nib") }
        view.translatesAutoresizingMaskIntoConstraints = false
        view.leadingAnchor.constraint(equalTo: self.safeAreaLayoutGuide.leadingAnchor, constant: 0).isActive = true
        view.topAnchor.constraint(equalTo: self.safeAreaLayoutGuide.topAnchor, constant: 0).isActive = true
        view.trailingAnchor.constraint(equalTo: self.safeAreaLayoutGuide.trailingAnchor, constant: 0).isActive = true
        view.bottomAnchor.constraint(equalTo: self.safeAreaLayoutGuide.bottomAnchor, constant: 0).isActive = true

And here is an example of MyCustomClass that implements the protocol (with the .xib file being named MyCustomClass.xib):

class MyCustomClass: UIView, NibLoadable {

    @IBOutlet weak var myLabel: UILabel!

    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)

    override init(frame: CGRect) {
        super.init(frame: frame)


NOTE: If you miss the Gotcha and set the class value inside your .xib file to be your custom class, then it will not draw in the storyboard and you will get a EXC_BAD_ACCESS error when you run the app because it gets stuck in an infinite loop of trying to initialize the class from the nib using the init?(coder aDecoder: NSCoder) method which then calls Self.nib.instantiate and calls the init again.

How to slice a Pandas Data Frame by position?

You can also do as a convenience:


How to try convert a string to a Guid

This will get you pretty close, and I use it in production and have never had a collision. However, if you look at the constructor for a guid in reflector, you will see all of the checks it makes.

 public static bool GuidTryParse(string s, out Guid result)
        if (!String.IsNullOrEmpty(s) && guidRegEx.IsMatch(s))
            result = new Guid(s);
            return true;

        result = default(Guid);
        return false;

    static Regex guidRegEx = new Regex("^[A-Fa-f0-9]{32}$|" +
                          "^({|\\()?[A-Fa-f0-9]{8}-([A-Fa-f0-9]{4}-){3}[A-Fa-f0-9]{12}(}|\\))?$|" +
                          "^({)?[0xA-Fa-f0-9]{3,10}(, {0,1}[0xA-Fa-f0-9]{3,6}){2}, {0,1}({)([0xA-Fa-f0-9]{3,4}, {0,1}){7}[0xA-Fa-f0-9]{3,4}(}})$", RegexOptions.Compiled);

How are zlib, gzip and zip related? What do they have in common and how are they different?

The most important difference is that gzip is only capable to compress a single file while zip compresses multiple files one by one and archives them into one single file afterwards. Thus, gzip comes along with tar most of the time (there are other possibilities, though). This comes along with some (dis)advantages.

If you have a big archive and you only need one single file out of it, you have to decompress the whole gzip file to get to that file. This is not required if you have a zip file.

On the other hand, if you compress 10 similiar or even identical files, the zip archive will be much bigger because each file is compressed individually, whereas in gzip in combination with tar a single file is compressed which is much more effective if the files are similiar (equal).

Cross field validation with Hibernate Validator (JSR 303)

You need to call it explicitly. In the example above, bradhouse has given you all the steps to write a custom constraint.

Add this code in your caller class.

ValidatorFactory factory = Validation.buildDefaultValidatorFactory();
validator = factory.getValidator();

Set<ConstraintViolation<yourObjectClass>> constraintViolations = validator.validate(yourObject);

in the above case it would be

Set<ConstraintViolation<AccountCreateForm>> constraintViolations = validator.validate(objAccountCreateForm);

How to use Git for Unity3D source control?

I would rather prefer that you use BitBucket, as it is not public and there is an official tutorial by Unity on Bitbucket.

hope this helps.

How to use awk sort by column 3

To exclude the first line (header) from sorting, I split it out into two buffers.

df | awk 'BEGIN{header=""; $body=""} { if(NR==1){header=$0}else{body=body"\n"$0}} END{print header; print body|"sort -nk3"}'

Is it possible to use "return" in stored procedure?

CREATE PROCEDURE pr_emp(dept_id IN NUMBER,vv_ename out varchar2  )
 v_ename emp%rowtype;
    SELECT ename
    FROM emp where deptno=dept_id;
     OPEN c;
        FETCH c_emp INTO v_ename;
        return v_ename; 
        vv_ename := v_ename 
        exit when c_emp%notfound;
     end loop;
     CLOSE c_emp;

 END pr_emp;

How do I convert ticks to minutes?


How to avoid annoying error "declared and not used"

That error is here to force you to write better code, and be sure to use everything you declare or import. It makes it easier to read code written by other people (you are always sure that all declared variables will be used), and avoid some possible dead code.

But, if you really want to skip this error, you can use the blank identifier (_) :

package main

import (
    "fmt" // imported and not used: "fmt"

func main() {
    i := 1 // i declared and not used


package main

import (
    _ "fmt" // no more error

func main() {
    i := 1 // no more error
    _ = i

As said by kostix in the comments below, you can find the official position of the Go team in the FAQ:

The presence of an unused variable may indicate a bug, while unused imports just slow down compilation. Accumulate enough unused imports in your code tree and things can get very slow. For these reasons, Go allows neither.

HTML meta tag for content language

another language meta tag is og:locale and you can define og:locale meta tag for social media

<meta property="og:locale" content="en" />

How can I give an imageview click effect like a button on Android?

Thanks for the help on this thread. However, you missed one need to handle the ACTION_CANCEL as well. If you don't then you might not properly restore the alpha value of the ImageView in the event that a parent view in the view hierarchy intercepts a touch event (think a ScrollView wrapping you ImageView).

Here is a complete class that is based off the above class but takes care of the ACTION_CANCEL as well. It uses an ImageViewCompat helper class to abstract the differences in the pre-post JellyBean API.

public class ChangeAlphaOnPressedTouchListener implements OnTouchListener {

    private final float pressedAlpha;

    public ChangeAlphaOnPressedTouchListener(float pressedAlpha) {
        this.pressedAlpha = pressedAlpha;

    public boolean onTouch(View v, MotionEvent event) {
        ImageView iv = (ImageView) v;
        switch (event.getAction()) {
        case MotionEvent.ACTION_DOWN:
            ImageViewCompat.setAlpha(iv, pressedAlpha);

        case MotionEvent.ACTION_MOVE:
            if (isInsideViewBounds(v, event)) {
                ImageViewCompat.setAlpha(iv, pressedAlpha);
            } else {
                ImageViewCompat.setAlpha(iv, 1f);
        case MotionEvent.ACTION_UP:
            ImageViewCompat.setAlpha(iv, 1f);
        case MotionEvent.ACTION_CANCEL:
            ImageViewCompat.setAlpha(iv, 1f);
        return false;

    private static boolean isInsideViewBounds(View v, MotionEvent event) {
        return event.getX() > 0 && event.getX() < v.getWidth() && event.getY() > 0
                && event.getY() < v.getHeight();

Get specific line from text file using just shell script

You could use sed -n 5p file.

You can also get a range, e.g., sed -n 5,10p file.

How to display a "busy" indicator with jQuery?

I did it in my project:

Global Events in application.js:

$(document).bind("ajaxSend", function(){
 }).bind("ajaxComplete", function(){

"loading" is the element to show and hide!


Add event handler for body.onload by javascript within <body> part

You should really use the following instead (works in all newer browsers):

window.addEventListener('DOMContentLoaded', init, false);

Call PHP function from Twig template

Its not possible to access any PHP function inside Twig directly.

What you can do is write a Twig extension. A common structure is, writing a service with some utility functions, write a Twig extension as bridge to access the service from twig. The Twig extension will use the service and your controller can use the service too.

Take a look:


Import CSV to mysql table

Use TablePlus application: Right-Click on the table name from the right panel Choose Import... > From CSV Choose CSV file Review column matching and hit Import All done!

Conditional Replace Pandas

The reason your original dataframe does not update is because chained indexing may cause you to modify a copy rather than a view of your dataframe. The docs give this advice:

When setting values in a pandas object, care must be taken to avoid what is called chained indexing.

You have a few alternatives:-

loc + Boolean indexing

loc may be used for setting values and supports Boolean masks:

df.loc[df['my_channel'] > 20000, 'my_channel'] = 0

mask + Boolean indexing

You can assign to your series:

df['my_channel'] = df['my_channel'].mask(df['my_channel'] > 20000, 0)

Or you can update your series in place:

df['my_channel'].mask(df['my_channel'] > 20000, 0, inplace=True)

np.where + Boolean indexing

You can use NumPy by assigning your original series when your condition is not satisfied; however, the first two solutions are cleaner since they explicitly change only specified values.

df['my_channel'] = np.where(df['my_channel'] > 20000, 0, df['my_channel'])

Get week of year in JavaScript like in PHP

Here is a slight adaptation for Typescript that will also return the dates for the week start and week end. I think it's common to have to display those in a user interface, since people don't usually remember week numbers.

function getWeekNumber(d: Date) {
  // Copy date so don't modify original
  d = new Date(Date.UTC(d.getFullYear(), d.getMonth(), d.getDate()));
  // Set to nearest Thursday: current date + 4 - current day number Make
  // Sunday's day number 7
  d.setUTCDate(d.getUTCDate() + 4 - (d.getUTCDay() || 7));
  // Get first day of year
  const yearStart = new Date(Date.UTC(d.getUTCFullYear(), 0, 1));
  // Calculate full weeks to nearest Thursday
  const weekNo = Math.ceil(
    ((d.getTime() - yearStart.getTime()) / 86400000 + 1) / 7

  const weekStartDate = new Date(d.getTime());
  weekStartDate.setUTCDate(weekStartDate.getUTCDate() - 3);

  const weekEndDate = new Date(d.getTime());
  weekEndDate.setUTCDate(weekEndDate.getUTCDate() + 3);

  return [d.getUTCFullYear(), weekNo, weekStartDate, weekEndDate] as const;

How can I auto-elevate my batch file, so that it requests from UAC administrator rights if required?

Try this:

@echo off
setlocal DisableDelayedExpansion
set cmdInvoke=1
set winSysFolder=System32
set "batchPath=%~0"
for %%k in (%0) do set batchName=%%~nk
set "vbsGetPrivileges=%temp%\OEgetPriv_%batchName%.vbs"
setlocal EnableDelayedExpansion
if '%errorlevel%' == '0' ( goto gotPrivileges ) else ( goto getPrivileges )
if '%1'=='ELEV' (echo ELEV & shift /1 & goto gotPrivileges)
ECHO Set UAC = CreateObject^("Shell.Application"^) > "%vbsGetPrivileges%"
ECHO args = "ELEV " >> "%vbsGetPrivileges%"
ECHO For Each strArg in WScript.Arguments >> "%vbsGetPrivileges%"
ECHO args = args ^& strArg ^& " "  >> "%vbsGetPrivileges%"
ECHO Next >> "%vbsGetPrivileges%"
if '%cmdInvoke%'=='1' goto InvokeCmd 
ECHO UAC.ShellExecute "!batchPath!", args, "", "runas", 1 >> "%vbsGetPrivileges%"
goto ExecElevation
ECHO args = "/c """ + "!batchPath!" + """ " + args >> "%vbsGetPrivileges%"
ECHO UAC.ShellExecute "%SystemRoot%\%winSysFolder%\cmd.exe", args, "", "runas", 1 >> "%vbsGetPrivileges%"
"%SystemRoot%\%winSysFolder%\WScript.exe" "%vbsGetPrivileges%" %*
exit /B
setlocal & cd /d %~dp0
if '%1'=='ELEV' (del "%vbsGetPrivileges%" 1>nul 2>nul  &  shift /1)
REM Run shell as admin (example) - put here code as you like
ECHO %batchName% Arguments: P1=%1 P2=%2 P3=%3 P4=%4 P5=%5 P6=%6 P7=%7 P8=%8 P9=%9
cmd /k

If you need information on that batch file, run the HTML/JS/CSS Snippet:

document.getElementsByTagName("data")[0].innerHTML="ElevateBatch, version 4, release<br>Required Commands:<ul><li>CLS</li><li>SETLOCAL</li><li>SET</li><li>FOR</li><li>NET</li><li>IF</li><li>ECHO</li><li>GOTO</li><li>EXIT</li><li>DEL</li></ul>It auto-elevates the system and if the user presses No, it just doesn't do anything.<br>This CANNOT be used to create an Elevated Explorer.";

Background blur with CSS

You could make it through iframes... I made something, but my only problem for now is syncing those divs to scroll simultaneous... its terrible way, because its like you load 2 websites, but the only way I found... you could also work with divs and overflow I guess...

Converting a string to a date in a cell

I was struggling with this for some time and after some help on a post I was able to come up with this formula =(DATEVALUE(LEFT(XX,10)))+(TIMEVALUE(MID(XX,12,5))) where XX is the cell in reference.

I've come across many other forums with people asking the same thing and this, to me, seems to be the simplest answer. What this will do is return text that is copied in from this format 2014/11/20 11:53 EST and turn it in to a Date/Time format so it can be sorted oldest to newest. It works with short date/long date and if you want the time just format the cell to display time and it will show. Hope this helps anyone who goes searching around like I did.

converting drawable resource image into bitmap

Bitmap bitmap = BitmapFactory.decodeResource(context.getResources(), R.drawable.my_drawable);

Context can be your current Activity.

How to play videos in android from assets folder or raw folder?

It sounds maybe like you have the same issue as i do. instead of using MP4, is 3GPP possible? i think i used like HandBrake or something as the video converter... you just need to make sure you have the right encoder, like H.264x or something. sorry for being a little vague, it's been a while. Also, if it's possible, don't bother worrying about android 2.1 anymore, and also, something things just WILL NOT WORK IN EMULATOR. so if it works on a lot of devices, then just assume it works (especially with different manufacurers)

here, you can read my problem and how i solved the issue (after a long time and no one had an answer). i explained in a lot more detail here: android media player not working

Run ssh and immediately execute command

You can use the LocalCommand command-line option if the PermitLocalCommand option is enabled:

ssh username@hostname -o LocalCommand="tmux list-sessions"

For more details about the available options, see the ssh_config man page.

How do you assert that a certain exception is thrown in JUnit 4 tests?

try {
    my method();
    fail( "This method must thrwo" );
} catch (Exception ex) {

iterating over and removing from a map

Java 8 support a more declarative approach to iteration, in that we specify the result we want rather than how to compute it. Benefits of the new approach are that it can be more readable, less error prone.

public static void mapRemove() {

    Map<Integer, String> map = new HashMap<Integer, String>() {
            put(1, "one");
            put(2, "two");
            put(3, "three");

    map.forEach( (key, value) -> { 
        System.out.println( "Key: " + key + "\t" + " Value: " + value );  

    map.keySet().removeIf(e->(e>2)); // <-- remove here

    System.out.println("After removing element");

    map.forEach( (key, value) -> { 
        System.out.println( "Key: " + key + "\t" + " Value: " + value ); 

And result is as follows:

Key: 1   Value: one
Key: 2   Value: two
Key: 3   Value: three
After removing element
Key: 1   Value: one
Key: 2   Value: two

Rails: Can't verify CSRF token authenticity when making a POST request

Cross site request forgery (CSRF/XSRF) is when a malicious web page tricks users into performing a request that is not intended for example by using bookmarklets, iframes or just by creating a page which is visually similar enough to fool users.

The Rails CSRF protection is made for "classical" web apps - it simply gives a degree of assurance that the request originated from your own web app. A CSRF token works like a secret that only your server knows - Rails generates a random token and stores it in the session. Your forms send the token via a hidden input and Rails verifies that any non GET request includes a token that matches what is stored in the session.

However an API is usually by definition cross site and meant to be used in more than your web app, which means that the whole concept of CSRF does not quite apply.

Instead you should use a token based strategy of authenticating API requests with an API key and secret since you are verifying that the request comes from an approved API client - not from your own app.

You can deactivate CSRF as pointed out by @dcestari:

class ApiController < ActionController::Base
  protect_from_forgery with: :null_session

Updated. In Rails 5 you can generate API only applications by using the --api option:

rails new appname --api

They do not include the CSRF middleware and many other components that are superflouus.

PermGen elimination in JDK 8

The Permanent Generation (PermGen) space has completely been removed and is kind of replaced by a new space called Metaspace.The consequences of the PermGen removal is that obviously the PermSize and MaxPermSize JVM arguments are ignored and you will never get a java.lang.OutOfMemoryError: PermGen error. The JDK 8 HotSpot JVM is now using native memory for the representation of class metadata and is called Metaspace. Read More>>

Where is Ubuntu storing installed programs?

Simply, type the command:

~$ whereis "program name"

Validation error: "No validator could be found for type: java.lang.Integer"

As the question is asked simply use @Min(1) instead of @size on integer fields and it will work.

How to remove all white spaces in java


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

s - indicates space character (tab characters etc)

#1146 - Table 'phpmyadmin.pma_recent' doesn't exist

i've resolved with

sudo dpkg-reconfigure phpmyadmin

How to see if a directory exists or not in Perl?

Use -d (full list of file tests)

if (-d "cgi-bin") {
    # directory called cgi-bin exists
elsif (-e "cgi-bin") {
    # cgi-bin exists but is not a directory
else {
    # nothing called cgi-bin exists

As a note, -e doesn't distinguish between files and directories. To check if something exists and is a plain file, use -f.

How much data can a List can hold at the maximum?

It depends on the List implementation. Since you index arrays with ints, an ArrayList can't hold more than Integer.MAX_VALUE elements. A LinkedList isn't limited in the same way, though, and can contain any amount of elements.


This article covers an interesting relationship between ROW_NUMBER() and DENSE_RANK() (the RANK() function is not treated specifically). When you need a generated ROW_NUMBER() on a SELECT DISTINCT statement, the ROW_NUMBER() will produce distinct values before they are removed by the DISTINCT keyword. E.g. this query

  ROW_NUMBER() OVER (ORDER BY v) row_number
ORDER BY v, row_number

... might produce this result (DISTINCT has no effect):

| a |          1 |
| a |          2 |
| a |          3 |
| b |          4 |
| c |          5 |
| c |          6 |
| d |          7 |
| e |          8 |

Whereas this query:

  DENSE_RANK() OVER (ORDER BY v) row_number
ORDER BY v, row_number

... produces what you probably want in this case:

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

Note that the ORDER BY clause of the DENSE_RANK() function will need all other columns from the SELECT DISTINCT clause to work properly.

The reason for this is that logically, window functions are calculated before DISTINCT is applied.

All three functions in comparison

Using PostgreSQL / Sybase / SQL standard syntax (WINDOW clause):

  ROW_NUMBER() OVER (window) row_number,
  RANK()       OVER (window) rank,
  DENSE_RANK() OVER (window) dense_rank

... you'll get:

| a |          1 |    1 |          1 |
| a |          2 |    1 |          1 |
| a |          3 |    1 |          1 |
| b |          4 |    4 |          2 |
| c |          5 |    5 |          3 |
| c |          6 |    5 |          3 |
| d |          7 |    7 |          4 |
| e |          8 |    8 |          5 |

Get screen width and height in Android

This set of utilities to work with the Size abstraction in Android.

It contains a class You can use it like this:

ISize size = new SizeFromDisplay(getWindowManager().getDefaultDisplay());

Bootstrap : TypeError: $(...).modal is not a function

I was getting the same error because of jquery CDN (<script src=""></script>) was added two times in the HTML head.

Push item to associative array in PHP

There is a better way to do this:

If the array $arr_options contains the existing array.

$arr_new_input['name'] = [
    'type' => 'text', 
    'label' => 'First name', 
    'show' => true, 
    'required' => true

$arr_options += $arr_new_input;

Warning: $arr_options must exist. if $arr_options already has a ['name'] it wil be overwritten.

Hope this helps.

Github permission denied: ssh add agent has no identities

try this:

ssh-add ~/.ssh/id_rsa

worked for me

How to access Winform textbox control from another class?

I used this method for updating a label but you could easily change it to a textbox:


public Class1
    public Form_Class formToOutput;

    public Class1(Form_Class f){
        formToOutput = f;

    // Then call this method and pass whatever string
    private void Write(string s)

Form methods that will do the updating:

public Form_Class{

    // Methods that will do the updating
    public void MethodToBeCalledByClass(string messageToSend)
       if (InvokeRequired) { 
           Invoke(new OutputDelegate(UpdateText),messageToSend); 

    public delegate void OutputDelegate(string messageToSend);
    public void UpdateText(string messageToSend)
       label1.Text = messageToSend;


Just pass the form through the constructor:

Class1 c = new Class1(this);

What does $ mean before a string?

The following example highlights various advantages of using interpolated strings over string.Format() as far as cleanliness and readability goes. It also shows that code within {} gets evaluated like any other function argument, just as it would if string.Format() we're being called.

using System;

public class Example
   public static void Main()
      var name = "Horace";
      var age = 34;
      // replaces {name} with the value of name, "Horace"
      var s1 = $"He asked, \"Is your name {name}?\", but didn't wait for a reply.";

      // as age is an integer, we can use ":D3" to denote that
      // it should have leading zeroes and be 3 characters long
      // see
      // (age == 1 ? "" : "s") uses the ternary operator to 
      // decide the value used in the placeholder, the same 
      // as if it had been placed as an argument of string.Format
      // finally, it shows that you can actually have quoted strings within strings
      // e.g. $"outer { "inner" } string"
      var s2 = $"{name} is {age:D3} year{(age == 1 ? "" : "s")} old.";
// The example displays the following output:
//       He asked, "Is your name Horace?", but didn't wait for a reply.
//       Horace is 034 years old.

Excel Looping through rows and copy cell values to another worksheet

Private Sub CommandButton1_Click() 

Dim Z As Long 
Dim Cellidx As Range 
Dim NextRow As Long 
Dim Rng As Range 
Dim SrcWks As Worksheet 
Dim DataWks As Worksheet 
Z = 1 
Set SrcWks = Worksheets("Sheet1") 
Set DataWks = Worksheets("Sheet2") 
Set Rng = EntryWks.Range("B6:ad6") 

NextRow = DataWks.UsedRange.Rows.Count 
NextRow = IIf(NextRow = 1, 1, NextRow + 1) 

For Each RA In Rng.Areas 
    For Each Cellidx In RA 
        Z = Z + 1 
        DataWks.Cells(NextRow, Z) = Cellidx 
    Next Cellidx 
Next RA 
End Sub


Worksheets("Sheet2").Range("P2").Value = Worksheets("Sheet1").Range("L10") 

This is a CopynPaste - Method

Sub CopyDataToPlan()

Dim LDate As String
Dim LColumn As Integer
Dim LFound As Boolean

On Error GoTo Err_Execute

'Retrieve date value to search for
LDate = Sheets("Rolling Plan").Range("B4").Value


'Start at column B
LColumn = 2
LFound = False

While LFound = False

  'Encountered blank cell in row 2, terminate search
  If Len(Cells(2, LColumn)) = 0 Then
     MsgBox "No matching date was found."
     Exit Sub

  'Found match in row 2
  ElseIf Cells(2, LColumn) = LDate Then

     'Select values to copy from "Rolling Plan" sheet
     Sheets("Rolling Plan").Select

     'Paste onto "Plan" sheet
     Cells(3, LColumn).Select
     Selection.PasteSpecial Paste:=xlValues, Operation:=xlNone, SkipBlanks:= _
     False, Transpose:=False

     LFound = True
     MsgBox "The data has been successfully copied."

     'Continue searching
         LColumn = LColumn + 1
      End If


   Exit Sub

  MsgBox "An error occurred."

End Sub

And there might be some methods doing that in Excel.

How to find Port number of IP address?

DNS server usually have a standard of ports used. But if it's different, you could try nmap and do a port scan like so:

> nmap

Getting request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource

Basically, to make a cross domain AJAX requests, the requested server should allow the cross origin sharing of resources (CORS). You can read more about that from here:

In your scenario, you are setting the headers in the client which in fact needs to be set into http://localhost:8080/app server side code.

If you are using PHP Apache server, then you will need to add following in your .htaccess file:

Header set Access-Control-Allow-Origin "*"

How to add a file to the last commit in git?

Yes, there's a command git commit --amend which is used to "fix" last commit.

In your case it would be called as:

git add the_left_out_file
git commit --amend --no-edit

The --no-edit flag allow to make amendment to commit without changing commit message.

EDIT: Warning You should never amend public commits, that you already pushed to public repository, because what amend does is actually removing from history last commit and creating new commit with combined changes from that commit and new added when amending.

JavaScript Form Submit - Confirm or Cancel Submission Dialog Box

The issue pointed in the comment is valid, so here is a different revision that's immune to that:

function show_alert() {
  if(!confirm("Do you really want to do this?")) {
    return false;