Programs & Examples On #Groovlet

Chart.js canvas resize

Add div and it will solve the problem

<div style="position:absolute; top:50px; left:10px; width:500px; height:500px;"></div>

addClass and removeClass in jQuery - not removing class

I think you're almost there. The thing is, your $(this) in the "close button" listener is not the clickable div. So you want to search it first. try to replace $(this) with $(this).closest(".clickable") . And don't forget the e.stopPropagation() as Guilherme is suggesting. that should be something like:

$( document ).ready(function() {   
    $(document).on("click", ".close_button", function () { 
        alert ("oi");

    $(document).on("click", ".clickable", function () {
        if ($(this).hasClass("spot")){

PDF Editing in PHP?

If you need really simple PDFs, then Zend or FPDF is fine. However I find them difficult and frustrating to work with. Also, because of the way the API works, there's no good way to separate content from presentation from business logic.

For that reason, I use dompdf, which automatically converts HTML and CSS to PDF documents. You can lay out a template just as you would for an HTML page and use standard HTML syntax. You can even include an external CSS file. The library isn't perfect and very complex markup or css sometimes gets mangled, but I haven't found anything else that works as well.

How do you make strings "XML safe"?

I prefer the way Golang does quote escaping for XML (and a few extras like newline escaping, and escaping some other characters), so I have ported its XML escape function to PHP below

function isInCharacterRange(int $r): bool {
    return $r == 0x09 ||
            $r == 0x0A ||
            $r == 0x0D ||
            $r >= 0x20 && $r <= 0xDF77 ||
            $r >= 0xE000 && $r <= 0xFFFD ||
            $r >= 0x10000 && $r <= 0x10FFFF;

function xml(string $s, bool $escapeNewline = true): string {
    $w = '';

    $Last = 0;
    $l = strlen($s);
    $i = 0;

    while ($i < $l) {
        $r = mb_substr(substr($s, $i), 0, 1);
        $Width = strlen($r);
        $i += $Width;
        switch ($r) {
            case '"':
                $esc = '&#34;';
            case "'":
                $esc = '&#39;';
            case '&':
                $esc = '&amp;';
            case '<':
                $esc = '&lt;';
            case '>':
                $esc = '&gt;';
            case "\t":
                $esc = '&#x9;';
            case "\n":
                if (!$escapeNewline) {
                    continue 2;
                $esc = '&#xA;';
            case "\r":
                $esc = '&#xD;';
                if (!isInCharacterRange(mb_ord($r)) || (mb_ord($r) === 0xFFFD && $Width === 1)) {
                    $esc = "\u{FFFD}";

                continue 2;
        $w .= substr($s, $Last, $i - $Last - $Width) . $esc;
        $Last = $i;
    $w .= substr($s, $Last);
    return $w;

Note you'll need at least PHP7.2 because of the mb_ord usage, or you'll have to swap it out for another polyfill, but these functions are working great for us!

For anyone curious, here is the relevant Go source

Change Placeholder Text using jQuery

$(this).val() is a string. Use parseInt($(this).val(), 10) or check for '1'. The ten is to denote base 10.

$(function () {
    $('input[placeholder], textarea[placeholder]').blur();
    $('#serMemdd').change(function () {
        var k = $(this).val();
        if (k == '1') {
            $("#serMemtb").attr("placeholder", "Type a name (Lastname, Firstname)").blur();
        else if (k == '2') {
            $("#serMemtb").attr("placeholder", "Type an ID").blur();
        else if (k == '3') {
            $("#serMemtb").attr("placeholder", "Type a Location").blur();


$(function () {
    $('input[placeholder], textarea[placeholder]').placeholder();
    $('#serMemdd').change(function () {
        var k = parseInt($(this).val(), 10);
        if (k == 1) {
            $("#serMemtb").attr("placeholder", "Type a name (Lastname, Firstname)").blur();
        else if (k == 2) {
            $("#serMemtb").attr("placeholder", "Type an ID").blur();
        else if (k == 3) {
            $("#serMemtb").attr("placeholder", "Type a Location").blur();

Other Plugins

ori has brought to my attention that the plugin you are using does not overcome IEs HTML failure.

Try something like this:

Java: Literal percent sign in printf statement

The percent sign is escaped using a percent sign:


The complete syntax can be accessed in java docs. This particular information is in the section Conversions of the first link.

The reason the compiler is generating an error is that only a limited amount of characters may follow a backslash. % is not a valid character.

How can I draw circle through XML Drawable - Android?

no need for the padding or the corners.

here's a sample:

<shape xmlns:android="" android:shape="oval" >
    <gradient android:startColor="#FFFF0000" android:endColor="#80FF00FF"

based on :

More Pythonic Way to Run a Process X Times

The for loop is definitely more pythonic, as it uses Python's higher level built in functionality to convey what you're doing both more clearly and concisely. The overhead of range vs xrange, and assigning an unused i variable, stem from the absence of a statement like Verilog's repeat statement. The main reason to stick to the for range solution is that other ways are more complex. For instance:

from itertools import repeat

for unused in repeat(None, 10):
    del unused   # redundant and inefficient, the name is clear enough
    print "This is run 10 times"

Using repeat instead of range here is less clear because it's not as well known a function, and more complex because you need to import it. The main style guides if you need a reference are PEP 20 - The Zen of Python and PEP 8 - Style Guide for Python Code.

We also note that the for range version is an explicit example used in both the language reference and tutorial, although in that case the value is used. It does mean the form is bound to be more familiar than the while expansion of a C-style for loop.

Sorted collection in Java

Sorting an ArrayList according to user defined criteria.

Model Class

 class Student 
     int rollno; 
     String name, address; 

     public Student(int rollno, String name, String address) 
         this.rollno = rollno;  = name; 
         this.address = address; 

     public String toString() 
         return this.rollno + " " + + " " + this.address; 

Sorting Class

 class Sortbyroll implements Comparator<Student> 
     public int compare(Student a, Student b) 
         return a.rollno - b.rollno; 

Main Class

 class Main 
     public static void main (String[] args) 
         ArrayList<Student> ar = new ArrayList<Student>(); 
         ar.add(new Student(111, "bbbb", "london")); 
         ar.add(new Student(131, "aaaa", "nyc")); 
         ar.add(new Student(121, "cccc", "jaipur")); 

         for (int i=0; i<ar.size(); i++) 

         Collections.sort(ar, new Sortbyroll()); 

         System.out.println("\nSorted by rollno"); 
         for (int i=0; i<ar.size(); i++) 


 111 bbbb london
 131 aaaa nyc
 121 cccc jaipur

 Sorted by rollno
 111 bbbb london
 121 cccc jaipur
 131 aaaa nyc

Add a new column to existing table in a migration

Laravel 7

  1. Create a migration file using cli command:

    php artisan make:migration add_paid_to_users_table --table=users

  2. A file will be created in the migrations folder, open it in an editor.

  3. Add to the function up():

Schema::table('users', function (Blueprint $table) {
    // Create new column
    // You probably want to make the new column nullable
  1. Add to the function down(), this will run in case migration fails for some reasons:


  2. Run migration using cli command:

    php artisan migrate

In case you want to add a column to the table to create a foreign key constraint:

In step 3 of the above process, you'll use the following code:


$table->foreign('address_id')->references('id')->on('addresses')->onDelete('SET NULL');

In step 4 of the above process, you'll use the following code:

// 1. Drop foreign key constraints
// 2. Drop the column

Raise error in a Bash script

Basic error handling

If your test case runner returns a non-zero code for failed tests, you can simply write:

test_handler test_case_x; test_result=$?
if ((test_result != 0)); then
  printf '%s\n' "Test case x failed" >&2  # write error message to stderr
  exit 1                                  # or exit $test_result

Or even shorter:

if ! test_handler test_case_x; then
  printf '%s\n' "Test case x failed" >&2
  exit 1

Or the shortest:

test_handler test_case_x || { printf '%s\n' "Test case x failed" >&2; exit 1; }

To exit with test_handler's exit code:

test_handler test_case_x || { ec=$?; printf '%s\n' "Test case x failed" >&2; exit $ec; }

Advanced error handling

If you want to take a more comprehensive approach, you can have an error handler:

exit_if_error() {
  local exit_code=$1
  [[ $exit_code ]] &&               # do nothing if no error code passed
    ((exit_code != 0)) && {         # do nothing if error code is 0
      printf 'ERROR: %s\n' "$@" >&2 # we can use better logging here
      exit "$exit_code"             # we could also check to make sure
                                    # error code is numeric when passed

then invoke it after running your test case:

run_test_case test_case_x
exit_if_error $? "Test case x failed"


run_test_case test_case_x || exit_if_error $? "Test case x failed"

The advantages of having an error handler like exit_if_error are:

  • we can standardize all the error handling logic such as logging, printing a stack trace, notification, doing cleanup etc., in one place
  • by making the error handler get the error code as an argument, we can spare the caller from the clutter of if blocks that test exit codes for errors
  • if we have a signal handler (using trap), we can invoke the error handler from there

Error handling and logging library

Here is a complete implementation of error handling and logging:

Related posts

Cannot read property 'style' of undefined -- Uncaught Type Error

It's currently working, I've just changed the operator > in order to work in the snippet, take a look:

window.onload = function() {_x000D_
  if (window.location.href.indexOf("test") <= -1) {_x000D_
    var search_span = document.getElementsByClassName("securitySearchQuery");_x000D_
    search_span[0].style.color = "blue";_x000D_
    search_span[0].style.fontWeight = "bold";_x000D_
    search_span[0].style.fontSize = "40px";_x000D_
<h1 class="keyword-title">Search results for<span class="securitySearchQuery"> "hi".</span></h1>

Refresh Page C# ASP.NET


What's the opposite of 'make install', i.e. how do you uninstall a library in Linux?

Depending on how well the makefile/configure script/autofoo magic of the program in question is the following might solve your problem:

make uninstall

The problem is that you should execute this on the source tree of the version you've got installed and with exactly the same configuration that you used for installing.

JavaScript push to array

object["property"] = value;

or = value;

Object and Array in JavaScript are different in terms of usage. Its best if you understand them:

Object vs Array: JavaScript

How to fix this Error: #include <gl/glut.h> "Cannot open source file gl/glut.h"

If you are using Visual Studio Community 2015 and trying to Install GLUT you should place the header file glut.h in C:\Program Files (x86)\Windows Kits\8.1\Include\um\gl

Get json value from response

If response is in json and not a string then



var response = JSON.parse('{"id":"2231f87c-a62c-4c2c-8f5d-b76d11942301"}'); ; //# => 2231f87c-a62c-4c2c-8f5d-b76d11942301

Restoring MySQL database from physical files

A MySQL MyISAM table is the combination of three files:

  • The FRM file is the table definition.
  • The MYD file is where the actual data is stored.
  • The MYI file is where the indexes created on the table are stored.

You should be able to restore by copying them in your database folder (In linux, the default location is /var/lib/mysql/)

You should do it while the server is not running.

VBA Excel Provide current Date in Text box

Use the form Initialize event, e.g.:

Private Sub UserForm_Initialize()
    TextBox1.Value = Format(Date, "mm/dd/yyyy")
End Sub

"register" keyword in C?


C, as a language, is an abstraction of a computer. It allows you to do things, in terms of what a computer does, that is manipulate memory, do math, print things, etc.

But C is only an abstraction. And ultimately, what it's extracting from you is Assembly language. Assembly is the language that a CPU reads, and if you use it, you do things in terms of the CPU. What does a CPU do? Basically, it reads from memory, does math, and writes to memory. The CPU doesn't just do math on numbers in memory. First, you have to move a number from memory to memory inside the CPU called a register. Once you're done doing whatever you need to do to this number, you can move it back to normal system memory. Why use system memory at all? Registers are limited in number. You only get about a hundred bytes in modern processors, and older popular processors were even more fantastically limited (The 6502 had 3 8-bit registers for your free use). So, your average math operation looks like:

load first number from memory
load second number from memory
add the two
store answer into memory

A lot of that is... not math. Those load and store operations can take up to half your processing time. C, being an abstraction of computers, freed the programmer the worry of using and juggling registers, and since the number and type vary between computers, C places the responsibility of register allocation solely on the compiler. With one exception.

When you declare a variable register, you are telling the compiler "Yo, I intend for this variable to be used a lot and/or be short lived. If I were you, I'd try to keep it in a register." When the C standard says compilers don't have to actually do anything, that's because the C standard doesn't know what computer you're compiling for, and it might be like the 6502 above, where all 3 registers are needed just to operate, and there's no spare register to keep your number. However, when it says you can't take the address, that's because registers don't have addresses. They're the processor's hands. Since the compiler doesn't have to give you an address, and since it can't have an address at all ever, several optimizations are now open to the compiler. It could, say, keep the number in a register always. It doesn't have to worry about where it's stored in computer memory (beyond needing to get it back again). It could even pun it into another variable, give it to another processor, give it a changing location, etc.

tl;dr: Short-lived variables that do lots of math. Don't declare too many at once.

How to automatically generate unique id in SQL like UID12345678?

The only viable solution in my opinion is to use

  • an ID INT IDENTITY(1,1) column to get SQL Server to handle the automatic increment of your numeric value
  • a computed, persisted column to convert that numeric value to the value you need

So try this:

CREATE TABLE dbo.tblUsers
   UserID AS 'UID' + RIGHT('00000000' + CAST(ID AS VARCHAR(8)), 8) PERSISTED,
   .... your other columns here....

Now, every time you insert a row into tblUsers without specifying values for ID or UserID:

INSERT INTO dbo.tblUsersCol1, Col2, ..., ColN)
VALUES (Val1, Val2, ....., ValN)

then SQL Server will automatically and safely increase your ID value, and UserID will contain values like UID00000001, UID00000002,...... and so on - automatically, safely, reliably, no duplicates.

Update: the column UserID is computed - but it still OF COURSE has a data type, as a quick peek into the Object Explorer reveals:

enter image description here

Difference between numeric, float and decimal in SQL Server

Guidelines from MSDN: Using decimal, float, and real Data

The default maximum precision of numeric and decimal data types is 38. In Transact-SQL, numeric is functionally equivalent to the decimal data type. Use the decimal data type to store numbers with decimals when the data values must be stored exactly as specified.

The behavior of float and real follows the IEEE 754 specification on approximate numeric data types. Because of the approximate nature of the float and real data types, do not use these data types when exact numeric behavior is required, such as in financial applications, in operations involving rounding, or in equality checks. Instead, use the integer, decimal, money, or smallmoney data types. Avoid using float or real columns in WHERE clause search conditions, especially the = and <> operators. It is best to limit float and real columns to > or < comparisons.

Validating input using java.util.Scanner

Overview of Scanner.hasNextXXX methods

java.util.Scanner has many hasNextXXX methods that can be used to validate input. Here's a brief overview of all of them:

Scanner is capable of more, enabled by the fact that it's regex-based. One important feature is useDelimiter(String pattern), which lets you define what pattern separates your tokens. There are also find and skip methods that ignores delimiters.

The following discussion will keep the regex as simple as possible, so the focus remains on Scanner.

Example 1: Validating positive ints

Here's a simple example of using hasNextInt() to validate positive int from the input.

Scanner sc = new Scanner(;
int number;
do {
    System.out.println("Please enter a positive number!");
    while (!sc.hasNextInt()) {
        System.out.println("That's not a number!");; // this is important!
    number = sc.nextInt();
} while (number <= 0);
System.out.println("Thank you! Got " + number);

Here's an example session:

Please enter a positive number!
That's not a number!
Please enter a positive number!
Thank you! Got 5

Note how much easier Scanner.hasNextInt() is to use compared to the more verbose try/catch Integer.parseInt/NumberFormatException combo. By contract, a Scanner guarantees that if it hasNextInt(), then nextInt() will peacefully give you that int, and will not throw any NumberFormatException/InputMismatchException/NoSuchElementException.

Related questions

Example 2: Multiple hasNextXXX on the same token

Note that the snippet above contains a statement to advance the Scanner until it hasNextInt(). It's important to realize that none of the hasNextXXX methods advance the Scanner past any input! You will find that if you omit this line from the snippet, then it'd go into an infinite loop on an invalid input!

This has two consequences:

  • If you need to skip the "garbage" input that fails your hasNextXXX test, then you need to advance the Scanner one way or another (e.g. next(), nextLine(), skip, etc).
  • If one hasNextXXX test fails, you can still test if it perhaps hasNextYYY!

Here's an example of performing multiple hasNextXXX tests.

Scanner sc = new Scanner(;
while (!sc.hasNext("exit")) {
        sc.hasNextInt() ? "(int) " + sc.nextInt() :
        sc.hasNextLong() ? "(long) " + sc.nextLong() :  
        sc.hasNextDouble() ? "(double) " + sc.nextDouble() :
        sc.hasNextBoolean() ? "(boolean) " + sc.nextBoolean() :
        "(String) " +

Here's an example session:

(int) 5
(boolean) false
(String) blah
(double) 1.1
(long) 100000000000

Note that the order of the tests matters. If a Scanner hasNextInt(), then it also hasNextLong(), but it's not necessarily true the other way around. More often than not you'd want to do the more specific test before the more general test.

Example 3 : Validating vowels

Scanner has many advanced features supported by regular expressions. Here's an example of using it to validate vowels.

Scanner sc = new Scanner(;
System.out.println("Please enter a vowel, lowercase!");
while (!sc.hasNext("[aeiou]")) {
    System.out.println("That's not a vowel!");;
String vowel =;
System.out.println("Thank you! Got " + vowel);

Here's an example session:

Please enter a vowel, lowercase!
That's not a vowel!
That's not a vowel!
Thank you! Got e

In regex, as a Java string literal, the pattern "[aeiou]" is what is called a "character class"; it matches any of the letters a, e, i, o, u. Note that it's trivial to make the above test case-insensitive: just provide such regex pattern to the Scanner.

API links

Related questions


Example 4: Using two Scanner at once

Sometimes you need to scan line-by-line, with multiple tokens on a line. The easiest way to accomplish this is to use two Scanner, where the second Scanner takes the nextLine() from the first Scanner as input. Here's an example:

Scanner sc = new Scanner(;
System.out.println("Give me a bunch of numbers in a line (or 'exit')");
while (!sc.hasNext("exit")) {
    Scanner lineSc = new Scanner(sc.nextLine());
    int sum = 0;
    while (lineSc.hasNextInt()) {
        sum += lineSc.nextInt();
    System.out.println("Sum is " + sum);

Here's an example session:

Give me a bunch of numbers in a line (or 'exit')
3 4 5
Sum is 12
10 100 a million dollar
Sum is 110
wait what?
Sum is 0

In addition to Scanner(String) constructor, there's also Scanner( among others.


  • Scanner provides a rich set of features, such as hasNextXXX methods for validation.
  • Proper usage of hasNextXXX/nextXXX in combination means that a Scanner will NEVER throw an InputMismatchException/NoSuchElementException.
  • Always remember that hasNextXXX does not advance the Scanner past any input.
  • Don't be shy to create multiple Scanner if necessary. Two simple Scanner is often better than one overly complex Scanner.
  • Finally, even if you don't have any plans to use the advanced regex features, do keep in mind which methods are regex-based and which aren't. Any Scanner method that takes a String pattern argument is regex-based.
    • Tip: an easy way to turn any String into a literal pattern is to Pattern.quote it.

Php, wait 5 seconds before executing an action

before starting your actions, use


How can I set the focus (and display the keyboard) on my EditText programmatically

I finally figured out a solution and create a Kotlin class for it

object KeyboardUtils {

    fun showKeyboard(editText: EditText) {
        val imm = editText.context.getSystemService(Context.INPUT_METHOD_SERVICE) as InputMethodManager
        imm.showSoftInput(editText, 0)

    fun hideKeyboard(editText: EditText) {
        val imm = editText.context.getSystemService(Context.INPUT_METHOD_SERVICE) as InputMethodManager
        imm.hideSoftInputFromWindow(editText.windowToken, 0)


CSS Always On Top

Ensure position is on your element and set the z-index to a value higher than the elements you want to cover.

element {
    position: fixed;
    z-index: 999;

div {
    position: relative;
    z-index: 99;

It will probably require some more work than that but it's a start since you didn't post any code.

Flutter does not find android sdk

I spent a lot of time solving this.

Eventually what worked was going to project settings in android studio, sdk tools, uncheck hide obsolete packages and install sdk tools obsolete package.

Then run flutter doctor --android-licenses and then flutter doctor showed a green tick on my android toolchain.

Hope this helps someone.

Get all child views inside LinearLayout at once

((ViewGroup) findViewById(;// you can use this in an Activity to get your layout root view, then pass it to findAllEdittexts() method below.

Here I am iterating only EdiTexts, if you want all Views you can replace EditText with View.

SparseArray<EditText> array = new SparseArray<EditText>();

private void findAllEdittexts(ViewGroup viewGroup) {

    int count = viewGroup.getChildCount();
    for (int i = 0; i < count; i++) {
        View view = viewGroup.getChildAt(i);
        if (view instanceof ViewGroup)
            findAllEdittexts((ViewGroup) view);
        else if (view instanceof EditText) {
            EditText edittext = (EditText) view;
            array.put(editText.getId(), editText);

how to toggle attr() in jquery

$(".list-toggle").click(function() {
    $(this).hasAttr('colspan') ? 
        $(this).removeAttr('colspan') : $(this).attr('colspan', 6);

Difference between the System.Array.CopyTo() and System.Array.Clone()

The Clone() method returns a new array (a shallow copy) object containing all the elements in the original array. The CopyTo() method copies the elements into another existing array. Both perform a shallow copy. A shallow copy means the contents (each array element) contains references to the same object as the elements in the original array. A deep copy (which neither of these methods performs) would create a new instance of each element's object, resulting in a different, yet identical object.

So the difference are :

1- CopyTo require to have a destination array when Clone return a new array.
2- CopyTo let you specify an index (if required) to the destination array.

Remove the wrong example.

how to concat two columns into one with the existing column name in mysql?

Remove the * from your query and use individual column names, like this:


Using * means, in your results you want all the columns of the table. In your case * will also include FIRSTNAME. You are then concatenating some columns and using alias of FIRSTNAME. This creates 2 columns with same name.

Removing App ID from Developer Connection

App IDs cannot be removed because once allocated they need to stay alive so that another App ID doesn't accidentally collide with a previously existing App ID.

Apple should however support hiding unwanted App IDs (instead of completely deleting them) to reduce clutter.

Gradle - Could not target platform: 'Java SE 8' using tool chain: 'JDK 7 (1.7)'

I had a very related issue but for higher Java versions:

$ ./gradlew clean assemble

... <other normal Gradle output>

Could not target platform: 'Java SE 11' using tool chain: 'JDK 8 (1.8)'.

I noticed that the task succeeded when running using InteliJ. Adding a file (same level as build.gradle) called .java-version solved my issue:

 # .java-version

Import Certificate to Trusted Root but not to Personal [Command Line]

The below 'd help you to add the cert to the Root Store-

certutil -enterprise -f -v -AddStore "Root" <Cert File path>

This worked for me perfectly.

Array of strings in groovy

Most of the time you would create a list in groovy rather than an array. You could do it like this:

names = ["lucas", "Fred", "Mary"]

Alternately, if you did not want to quote everything like you did in the ruby example, you could do this:

names = "lucas Fred Mary".split()

How to find Current open Cursors in Oracle

1)your id should have sys dba access 2)

select sum(a.value) total_cur, avg(a.value) avg_cur, max(a.value) max_cur, 
 s.username, s.machine
 from v$sesstat a, v$statname b, v$session s 
 where a.statistic# = b.statistic# and s.sid=a.sid
 and = 'opened cursors current' 
 group by s.username, s.machine
 order by 1 desc;

Nginx 403 forbidden for all files

I've got this error and I finally solved it with the command below.

restorecon -r /var/www/html

The issue is caused when you mv something from one place to another. It preserves the selinux context of the original when you move it, so if you untar something in /home or /tmp it gets given an selinux context that matches its location. Now you mv that to /var/www/html and it takes the context saying it belongs in /tmp or /home with it and httpd is not allowed by policy to access those files.

If you cp the files instead of mv them, the selinux context gets assigned according to the location you're copying to, not where it's coming from. Running restorecon puts the context back to its default and fixes it too.

Could not determine the dependencies of task ':app:crashlyticsStoreDeobsDebug' if I enable the proguard

I was facing the same issue when integrating Firebase Cloud Store in my project. Inside the project level gradle, I added

classpath ''

that fixed the issue.

Is there a way to follow redirects with command line cURL?

Use the location header flag:

curl -L <URL>

Using with React components

First argument in update method is SyntheticEvent object that contains common properties and methods to any event, it is not reference to React component where there is property props.

if you need pass argument to update method you can do it like this

onClick={ (e) => this.props.onClick(e, 'home', 'Home') }

and get these arguments inside update method

update(e, space, txt){
   console.log(, space, txt);

Example gives you the native DOMNode, then you need to use the regular DOM APIs to access attributes. For instance getAttribute or dataset

  onClick={ this.props.onClick } 

onClick(e) {


How to change the server port from 3000?

If you don't have bs-config.json, you can change the port inside the lite-server module. Go to node_modules/lite-server/lib/config-defaults.js in your project, then add the port in "modules.export" like this.

module.export {
    port :8000, // to any available port

Then you can restart the server.

How to Empty Caches and Clean All Targets Xcode 4 and later

I had some problems with Xcode 5.1 crashing on me, when I opened the doc window.

I am not sure of the cause of it, because I was also updating docsets, while I opened the window.

Well, in Xcode 5 the modules directory now resides within the derived data folder, which I for obvious reasons didn't delete. I deleted the contents of ~/Library/Developer/Xcode/DerivedData/ModuleCache and the ~/Library/Preferences/ and everything then seems to work, after I restarted Xcode.

Delete entire row if cell contains the string X

This is not necessarily a VBA task - This specific task is easiest sollowed with Auto filter.

1.Insert Auto filter (In Excel 2010 click on home-> (Editing) Sort & Filter -> Filter)
2. Filter on the 'Websites' column
3. Mark the 'none' and delete them
4. Clear filter

0xC0000005: Access violation reading location 0x00000000

The problem here, as explained in other comments, is that the pointer is being dereference without being properly initialized. Operating systems like Linux keep the lowest addresses (eg first 32MB: 0x00_0000 -0x200_0000) out of the virtual address space of a process. This is done because dereferencing zeroed non-initialized pointers is a common mistake, like in this case. So when this type of mistake happens, instead of actually reading a random variable that happens to be at address 0x0 (but not the memory address the pointer would be intended for if initialized properly), the pointer would be reading from a memory address outside of the process's virtual address space. This causes a page fault, which results in a segmentation fault, and a signal is sent to the process to kill it. That's why you are getting the access violation error.

Sending data through POST request from a node.js server to a node.js server

Posting data is a matter of sending a query string (just like the way you would send it with an URL after the ?) as the request body.

This requires Content-Type and Content-Length headers, so the receiving server knows how to interpret the incoming data. (*)

var querystring = require('querystring');
var http = require('http');

var data = querystring.stringify({
      username: yourUsernameValue,
      password: yourPasswordValue

var options = {
    host: 'my.url',
    port: 80,
    path: '/login',
    method: 'POST',
    headers: {
        'Content-Type': 'application/x-www-form-urlencoded',
        'Content-Length': Buffer.byteLength(data)

var req = http.request(options, function(res) {
    res.on('data', function (chunk) {
        console.log("body: " + chunk);


(*) Sending data requires the Content-Type header to be set correctly, i.e. application/x-www-form-urlencoded for the traditional format that a standard HTML form would use.

It's easy to send JSON (application/json) in exactly the same manner; just JSON.stringify() the data beforehand.

URL-encoded data supports one level of structure (i.e. key and value). JSON is useful when it comes to exchanging data that has a nested structure.

The bottom line is: The server must be able to interpret the content type in question. It could be text/plain or anything else; there is no need to convert data if the receiving server understands it as it is.

Add a charset parameter (e.g. application/json; charset=Windows-1252) if your data is in an unusual character set, i.e. not UTF-8. This can be necessary if you read it from a file, for example.

dbms_lob.getlength() vs. length() to find blob size in oracle

length and dbms_lob.getlength return the number of characters when applied to a CLOB (Character LOB). When applied to a BLOB (Binary LOB), dbms_lob.getlength will return the number of bytes, which may differ from the number of characters in a multi-byte character set.

As the documentation doesn't specify what happens when you apply length on a BLOB, I would advise against using it in that case. If you want the number of bytes in a BLOB, use dbms_lob.getlength.

Can I use Objective-C blocks as properties?

@property (nonatomic, copy) void (^simpleBlock)(void);
@property (nonatomic, copy) BOOL (^blockWithParamter)(NSString *input);

If you are going to be repeating the same block in several places use a type def

typedef void(^MyCompletionBlock)(BOOL success, NSError *error);
@property (nonatomic) MyCompletionBlock completion;

Removing address bar from browser (to view on Android)

You can do that with the next code


I hope it helps you!

Error CS1705: "which has a higher version than referenced assembly"

The issue is seen if the nuget packages vary in multiple projects within the solution.

You can fix this by updating nuget packages to a common version with all of the PROJECTS in the SOLUTION

Android: disabling highlight on listView click

For me android:focusableInTouchMode="true" is the way to go. android:listSelector="@android:color/transparent" is of no use. Note that I am using a custom listview with a number of objects in each row.

Rebase feature branch onto another feature branch

  1. Switch to Branch2

    git checkout Branch2
  2. Apply the current (Branch2) changes on top of the Branch1 changes, staying in Branch2:

    git rebase Branch1

Which would leave you with the desired result in Branch2:

a -- b -- c                      <-- Master
            d -- e               <-- Branch1
            d -- e -- f' -- g'   <-- Branch2

You can delete Branch1.

How do I change JPanel inside a JFrame on the fly?

I suggest you to add both panel at frame creation, then change the visible panel by calling setVisible(true/false) on both. When calling setVisible, the parent will be notified and asked to repaint itself.

Trust Anchor not found for Android SSL Connection

In Gingerbread phones, I always get this error: Trust Anchor not found for Android SSL Connection, even if I setup to rely on my certificate.

Here is the code I use (in Scala language):

object Security {
    private def createCtxSsl(ctx: Context) = {
        val cer = {
            val is ="mycertificate.crt")
        val key = KeyStore.getInstance(KeyStore.getDefaultType)
        key.load(null, null)
        key.setCertificateEntry("ca", cer)

        val tmf = TrustManagerFactory.getInstance(TrustManagerFactory.getDefaultAlgorithm)

        val c = SSLContext.getInstance("TLS")
        c.init(null, tmf.getTrustManagers, null)

    def prepare(url: HttpURLConnection)(implicit ctx: Context) {
        url match {
            case https: HttpsURLConnection ?
                val cSsl = ctxSsl match {
                    case None ?
                        val res = createCtxSsl(ctx)
                        ctxSsl = Some(res)
                    case Some(c) ? c
            case _ ?

    def noSecurity(url: HttpURLConnection) {
        url match {
            case https: HttpsURLConnection ?
                https.setHostnameVerifier(new HostnameVerifier {
                    override def verify(hostname: String, session: SSLSession) = true
            case _ ?

and here is the connection code:

def connect(securize: HttpURLConnection ? Unit) {
    val conn = url.openConnection().asInstanceOf[HttpURLConnection]

try {
} catch {
    case ex: SSLHandshakeException /*if ex.getMessage != null && ex.getMessage.contains("Trust anchor for certification path not found")*/ ?

Basically, I setup to trust on my custom certificate. If that fails, then I disable security. This is not the best option, but the only choice I know with old and buggy phones.

This sample code, can be easily translated into Java.

ComboBox: Adding Text and Value to an Item (no Binding Source)

You must create your own class type and override the ToString() method to return the text you want. Here is a simple example of a class you can use:

public class ComboboxItem
    public string Text { get; set; }
    public object Value { get; set; }

    public override string ToString()
        return Text;

The following is a simple example of its usage:

private void Test()
    ComboboxItem item = new ComboboxItem();
    item.Text = "Item text1";
    item.Value = 12;


    comboBox1.SelectedIndex = 0;

    MessageBox.Show((comboBox1.SelectedItem as ComboboxItem).Value.ToString());

Error:(1, 0) Plugin with id '' not found

In my case, I download the project from GitHub and the Gradle file was missing. So I just create a new project with success build. Then copy-paste the Gradle missing file. And re-build the project is working for me.

enter image description here

How to Retrieve value from JTextField in Java Swing?


See the java doc for JTextField

Sample code can be:

button.addActionListener(new ActionListener(){
   public void actionPerformed(ActionEvent ae){
      String textFieldValue = testField.getText();
      // .... do some operation on value ...

How can I call PHP functions by JavaScript?

If you actually want to send data to a php script for example you can do this:

The php:

$a = $_REQUEST['a'];
$b = $_REQUEST['b']; //totally sanitized

echo $a + $b;

Js (using jquery):

$.post("/path/to/above.php", {a: something, b: something}, function(data){                                          

Should I make HTML Anchors with 'name' or 'id'?

ID method will not work on older browsers, anchor name method will be deprecated in newer HTML versions... I'd go with id. Could not locate executable null\bin\winutils.exe in the Hadoop binaries. spark Eclipse on windows 7

  1. Download winutils.exe
  2. Create folder, say C:\winutils\bin
  3. Copy winutils.exe inside C:\winutils\bin
  4. Set environment variable HADOOP_HOME to C:\winutils

Javascript - Open a given URL in a new tab by clicking a button

Try this HTML:

<input type="button" value="Button_name" onclick="'LINKADDRESS')"/>

How to convert upper case letters to lower case

To convert a string to lower case in Python, use something like this.


I found this in the first result after searching for "python upper to lower case".

Illegal character in path at index 16

the install directory can't have space. reinstall the software will correct it

Add Bean Programmatically to Spring Web App Context

Here is a simple code:

ConfigurableListableBeanFactory beanFactory = ((ConfigurableApplicationContext) applicationContext).getBeanFactory();
beanFactory.registerSingleton(bean.getClass().getCanonicalName(), bean);

jquery change class name

So you want to change it WHEN it's clicked...let me go through the whole process. Let's assume that your "External DOM Object" is an input, like a select:

Let's start with this HTML:

    <select id="test">

  <table id="theTable">
    <tr><td id="cellToChange">Bob</td><td>Sam</td></tr>

Some very basic CSS:

?#theTable td {
    border:1px solid #555;
.activeCell {

And set up a jQuery event:

function highlightCell(useVal){
  $("#theTable td").removeClass("activeCell")


Now, whenever you pick something from the select, it will automatically find a cell with the matching text, allowing you to subvert the whole id-based process. Of course, if you wanted to do it that way, you could easily modify the script to use IDs rather than values by saying


and make sure to add the ids appropriately. Hope this helps!

Streaming Audio from A URL in Android using MediaPlayer?

I guess that you are trying to play an .pls directly or something similar.

try this out:

1: the code

mediaPlayer = MediaPlayer.create(this, Uri.parse(""));

2: the .pls file

This URL is from BBC just as an example. It was an .pls file that on linux i downloaded with


and then i opened with vim (use your favorite editor ;) and i've seen the real URLs inside this file. Unfortunately not all of the .pls are plain text like that.

I've read that 1.6 would not support streaming mp3 over http, but, i've just tested the obove code with android 1.6 and 2.2 and didn't have any issue.

good luck!

Rails - passing parameters in link_to

link_to "+ Service", controller_action_path(:account_id =>

If it is still not working check the path:

$ rake routes

How to delete an SMS from the inbox in Android programmatically?

Its better to use the _id and thread_id to delete a message.

Thread_id is something assigned to the messages coming from same user. So, if you use only thread_id, all the messages from the sender will get deleted.

If u use the combination of _id, thread_id, then it will delete the exact message you are looking to delete.

Uri thread = Uri.parse( "content://sms");
int deleted = contentResolver.delete( thread, "thread_id=? and _id=?", new String[]{String.valueOf(thread_id), String.valueOf(id)} );

File content into unix variable with newlines

Just if someone is interested in another option:

content=( $(cat test.txt) )

while [ $a -le ${#content[@]} ]
        echo ${content[$a]}

Scanning Java annotations at runtime

The Classloader API doesn't have an "enumerate" method, because class loading is an "on-demand" activity -- you usually have thousands of classes in your classpath, only a fraction of which will ever be needed (the rt.jar alone is 48MB nowadays!).

So, even if you could enumerate all classes, this would be very time- and memory-consuming.

The simple approach is to list the concerned classes in a setup file (xml or whatever suits your fancy); if you want to do this automatically, restrict yourself to one JAR or one class directory.

What does the question mark in Java generics' type parameter mean?

A question mark is a signifier for 'any type'. ? alone means

Any type extending Object (including Object)

while your example above means

Any type extending or implementing HasWord (including HasWord if HasWord is a non-abstract class)

Adding a HTTP header to the Angular HttpClient doesn't send the header, why?

set http headers like below in your http request

return this.http.get(url, { headers: new HttpHeaders({'Authorization': 'Bearer ' + token})

Calling a JavaScript function returned from an Ajax response

It is fully possible, and there are even some fairly legitimate use cases for this. Using the Prototype framework it's done as follows.

new Ajax.Updater('items', '/items.url', {
    parameters: { evalJS: true}

See documentation of the Ajax updater. The options are in the common options set. As usual, there are some caveats about where "this" points to, so read the fine print.

The JavaScript code will be evaluated upon load. If the content contains function myFunc(), you could really just say myFunc() afterwards. Maybe as follows.

if (window["myFunc"])

This checks if the function exists. Maybe someone has a better cross-browser way of doing that which works in Internet Explorer 6.

Animate element to auto height with jQuery

I needed this functionality for multiple read more area's on one page implementing this into a Wordpress shortcode I ran into the same problem.

Design technically all of the read more span's on the page have a fixed height. And I wanted to be able to expand them separately to an auto height with a toggle. First click: 'expand to full height of text span', second click: 'collapse back to default height of 70px'


 <span class="read-more" data-base="70" data-height="null">
     /* Lots of text determining the height of this span */
 <button data-target='read-more'>Read more</button>


So above this looks very simple the data-base attribute I need to set the fixed height needed. The data-height attribute I used to store the actual (dynamic) height of the element.

The jQuery part


  $.fn.clickToggle = function(func1, func2) {
      var funcs = [func1, func2];'toggleclicked', 0); {
          var data = $(this).data();
          var tc = data.toggleclicked;
          $.proxy(funcs[tc], this)();
          data.toggleclicked = (tc + 1) % 2;
      return this;

    function setAttr_height(key) {
            var setNormalHeight = $(this).height();
            $(this).attr('data-height', setNormalHeight);
            $(this).css('height', $(this).attr('data-base') + 'px' );

        $(this).prev().animate({height: $(this).prev().attr('data-height')}, 200);
    }, function(){
        $(this).prev().animate({height: $(this).prev().attr('data-base')}, 200);


First I've used a clickToggle function for my first and second click. The second function is more important: setAttr_height() All of the .read-more elements have their actual heights set on page load in the base-height attribute. After that the base height is set through the jquery css function.

With both of our attributes set we now can toggle between them in a smooth way. Only chang the data-base to your desired (fixed)height and switch the .read-more class for your own ID

You can all see it working in a fiddle FIDDLE

No jQuery UI needed

Server certificate verification failed: issuer is not trusted

Just install the server certificate in the client's trusted root certificates container (if certified it's expired may not work). For further details see this post of similar question.

How do I center text vertically and horizontally in Flutter?

                       child: Align(
                          child: Text(
                            'Text here',

This produced the best result for me.

Bootstrap 3 - Responsive mp4-video

This worked for me:

<video src="file.mp4" controls style="max-width:100%; height:auto"></video>

Getting command-line password input in Python

import getpass

pswd = getpass.getpass('Password:')

getpass works on Linux, Windows, and Mac.

In nodeJs is there a way to loop through an array without using array size?

To print 'item1' , 'item2', this code would work.

var myarray = ['hello', ' hello again'];

for (var item in myarray) {

linux/videodev.h : no such file or directory - OpenCV on ubuntu 11.04

for CMake remove/disable with_libv4l with_v4l variables if you do not need this lib.

Dynamically Fill Jenkins Choice Parameter With Git Branches In a Specified Repo

I was able to achieve this result using the Jenkins Dynamic Parameter Plug-in. I used the Dynamic Choice Parameter option and, for the choices script, I used the following:

proc1 = ['/bin/bash', '-c', "/usr/bin/git ls-remote -h ssh://[email protected]/path/to/repo.git"].execute()
proc2 = ['/bin/bash', '-c', "awk '{print \$2}'"].execute()
proc3 = ['/bin/bash', '-c', "sed s%^refs/heads%origin%"].execute()

all = proc1 | proc2 | proc3
String result = all.text

String filename = "/tmp/branches.txt"
boolean success = new File(filename).write(result) 

def multiline = "cat /tmp/branches.txt".execute().text
def list = multiline.readLines()

How do you check in python whether a string contains only numbers?

What about of float numbers, negatives numbers, etc.. All the examples before will be wrong.

Until now I got something like this, but I think it could be a lot better:


will return true only if there is one or no '.' in the string of digits.


will return false

SonarQube Exclude a directory

If you're an Azure DevOps user looking for both where and how to exclude files and folders, here ya go:

  1. Edit your pipeline
  2. Make sure you have the "Prepare analysis on SonarQube" task added. You'll need to look elsewhere if you need help configuring this. Suggestion: Use the UI pipeline editor vs the yaml editor if you are missing the manage link. At present, there is no way to convert to UI from yaml. Just recreate the pipeline. If using git, you can delete the yaml from the root of your repo.
  3. Under the 'Advanced' section of the "Prepare analysis on SonarQube" task, you can add exclusions. See advice given by others for specific exclusion formats.


# Additional properties that will be passed to the scanner, 
# Put one key=value per line, example:
# sonar.exclusions=**/*.bin

Note: If you're not sure on the path, you can go into sonarqube, view your project, look at all or new 'Code Smells' and the path you need is listed above each grouping of issues. You can grab the full path to a file or use wilds like these examples:

  • MyProjectName/MyCodeFile.cs
  • MyProjectName/**

If you don't have the 'Run Code Analysis' task added, do that and place it somewhere after the 'Build solution **/*.sln' task.

Save and Queue and then check out your sonarqube server to see if the exclusions worked.

post ajax data to PHP and return data

            type: "POST",
            data: {data:the_id},
            url: "http://localhost/test/index.php/data/count_votes",
            success: function(data){
               //data will contain the vote count echoed by the controller i.e.  
              //then append the result where ever you want like
              $("span#votes_number").html(data); //data will be containing the vote count which you have echoed from the controller


in the controller

$data = $_POST['data'];  //$data will contain the_id
//do some processing
echo "yourVoteCount";


i think you are confusing




both the data are different for your own clarity sake you can modify it as


Select query with date condition

hey guys i think what you are looking for is this one using select command. With this you can specify a RANGE GREATER THAN(>) OR LESSER THAN(<) IN MySQL WITH THIS:::::

select* from <**TABLE NAME**> where year(**COLUMN NAME**) > **DATE** OR YEAR(COLUMN NAME )< **DATE**;


select name, BIRTH from pet1 where year(birth)> 1996 OR YEAR(BIRTH)< 1989;
| name     | BIRTH      |
| bowser   | 1979-09-11 |
| chirpy   | 1998-09-11 |
| whistler | 1999-09-09 |


mysql> select COLUMN NAME from <TABLE NAME> where year(COLUMN NAME)> 1996;


select name from pet1 where year(birth)> 1996 OR YEAR(BIRTH)< 1989;
| name     |
| bowser   |
| chirpy   |
| whistler |
3 rows in set (0.00 sec)

How can I search for a multiline pattern in a file?

This answer might be useful:

Regex (grep) for multi-line search needed

To find recursively you can use flags -R (recursive) and --include (GLOB pattern). See:

Use grep --exclude/--include syntax to not grep through certain files

Loop through columns and add string lengths as new columns

For the sake of completeness, there is also a data.table solution:

result <- setDT(df)[, paste0(names(df), "_length") := lapply(.SD, stringr::str_length)]
#      col1     col2 col1_length col2_length
#1:     abc adf qqwe           3           8
#2:    abcd        d           4           1
#3:       a        e           1           1
#4: abcdefg        f           7           1


to have the camera write to sdcard but keep in a new Album on the gallery app I use this :

 File imageDirectory = new File("/sdcard/signifio");
          String path = imageDirectory.toString().toLowerCase();
           String name = imageDirectory.getName().toLowerCase();

            ContentValues values = new ContentValues(); 
            values.put(Media.TITLE, "Image"); 
            values.put(Images.Media.BUCKET_ID, path.hashCode());

            values.put(Images.Media.MIME_TYPE, "image/jpeg");
            values.put(Media.DESCRIPTION, "Image capture by camera");
           values.put("_data", "/sdcard/signifio/1111.jpg");
         uri = getContentResolver().insert( Media.EXTERNAL_CONTENT_URI , values);
            Intent i = new Intent(""); 

            i.putExtra(MediaStore.EXTRA_OUTPUT, uri);

            startActivityForResult(i, 0); 

Please note that you will need to generate a unique filename every time and replace teh 1111.jpg that I wrote. This was tested with nexus one. the uri is declared in the private class , so on activity result I am able to load the image from the uri to imageView for preview if needed.

Create WordPress Page that redirects to another URL

You can accomplish this two ways, both of which need to be done through editing your template files.

The first one is just to add an html link to your navigation where ever you want it to show up.

The second (and my guess, the one you're looking for) is to create a new page template, which isn't too difficult if you have the ability to create a new .php file in your theme/template directory. Something like the below code should do:

<?php /*  
Template Name: Page Redirect



Where the template name is whatever you want to set it too and the url in the header function is the new url you want to direct a user to. After you modify the above code to meet your needs, save it in a php file in your active theme folder to the template name. So, if you leave the name of your template "Page Redirect" name the php file page-redirect.php.

After that's been saved, log into your WordPress backend, and create a new page. You can add a title and content to the body if you'd like, but the important thing to note is that on the right hand side, there should be a drop down option for you to choose which page template to use, with default showing first. In that drop down list, there should be the name of the new template file to use. Select the new template, publish the page, and you should be golden.

Also, you can do this dynamically as well by using the Custom Fields section below the body editor. If you're interested, let me know and I can paste the code for that guy in a new response.

"git rebase origin" vs."git rebase origin/master"

You can make a new file under [.git\refs\remotes\origin] with name "HEAD" and put content "ref: refs/remotes/origin/master" to it. This should solve your problem.

It seems that clone from an empty repos will lead to this. Maybe the empty repos do not have HEAD because no commit object exist.

You can use the

git log --remotes --branches --oneline --decorate

to see the difference between each repository, while the "problem" one do not have "origin/HEAD"

Edit: Give a way using command line
You can also use git command line to do this, they have the same result

git symbolic-ref refs/remotes/origin/HEAD refs/remotes/origin/master

Change CSS properties on click

This code seems to work fine (see this jsfiddle). Is your javascript defined before your body? When the browser reads onclick="myFunction()" it has to know what myFunction is.

How can I check for NaN values?

It seems that checking if it's equal to itself


is the fastest.

import pandas as pd 
import numpy as np 
import math 

x = float('nan')

%timeit x!=x                                                                                                                                                                                                                        
44.8 ns ± 0.152 ns per loop (mean ± std. dev. of 7 runs, 10000000 loops each)

%timeit math.isnan(x)                                                                                                                                                                                                               
94.2 ns ± 0.955 ns per loop (mean ± std. dev. of 7 runs, 10000000 loops each)

%timeit pd.isna(x) 
281 ns ± 5.48 ns per loop (mean ± std. dev. of 7 runs, 1000000 loops each)

%timeit np.isnan(x)                                                                                                                                                                                                                 
1.38 µs ± 15.7 ns per loop (mean ± std. dev. of 7 runs, 1000000 loops each)

mysqldump data only

Would suggest using the following snippet. Works fine even with huge tables (otherwise you'd open dump in editor and strip unneeded stuff, right? ;)

mysqldump --no-create-info --skip-triggers --extended-insert --lock-tables --quick DB TABLE > dump.sql

At least mysql 5.x required, but who runs old stuff nowadays.. :)

Is there an equivalent of 'which' on the Windows command line?

try this

set a=%~$dir:1
If "%for%"=="" (Echo %1 not found) else (echo %1 found at %a%)

Run git pull over all subdirectories

This should happen automatically, so long as cms, admin and chart are all parts of the repository.

A likely issue is that each of these plugins is a git submodule.

Run git help submodule for more information.


For doing this in bash:

cd plugins
for f in cms admin chart
  cd $f && git pull origin master && cd ..

How to create a simple http proxy in node.js?

I juste wrote a proxy in nodejs that take care of HTTPS with optional decoding of the message. This proxy also can add proxy-authentification header in order to go through a corporate proxy. You need to give as argument the url to find the proxy.pac file in order to configurate the usage of corporate proxy.

Java time-based map/cache with expiring keys

Typically, a cache should keep objects around some time and shall expose of them some time later. What is a good time to hold an object depends on the use case. I wanted this thing to be simple, no threads or schedulers. This approach works for me. Unlike SoftReferences, objects are guaranteed to be available some minimum amount of time. However, the do not stay around in memory until the sun turns into a red giant.

As useage example think of a slowly responding system that shall be able to check if a request has been done quite recently, and in that case not to perform the requested action twice, even if a hectic user hits the button several times. But, if the same action is requested some time later, it shall be performed again.

class Cache<T> {
    long avg, count, created, max, min;
    Map<T, Long> map = new HashMap<T, Long>();

     * @param min   minimal time [ns] to hold an object
     * @param max   maximal time [ns] to hold an object
    Cache(long min, long max) {
        created = System.nanoTime();
        this.min = min;
        this.max = max;
        avg = (min + max) / 2;

    boolean add(T e) {
        boolean result = map.put(e, Long.valueOf(System.nanoTime())) != null;
        return result;

    boolean contains(Object o) {
        boolean result = map.containsKey(o);
        return result;

    private void onAccess() {
        long now = System.nanoTime();
        for (Iterator<Entry<T, Long>> it = map.entrySet().iterator(); it.hasNext();) {
            long t =;
            if (now > t + min && (now > t + max || now + (now - created) / count > t + avg)) {

How do I use shell variables in an awk script?

I had to insert date at the beginning of the lines of a log file and it's done like below:

DATE=$(date +"%Y-%m-%d")
awk '{ print "'"$DATE"'", $0; }' /path_to_log_file/log_file.log

It can be redirect to another file to save

Error "There is already an open DataReader associated with this Command which must be closed first" when using 2 distinct commands

I bet the problem is being shown in this line

SqlDataReader dr3 = com2.ExecuteReader();

I suggest that you execute the first reader and do a dr.Close(); and the iterate historicos, with another loop, performing the com2.ExecuteReader().

public List<string[]> get_dados_historico_verificacao_email_WEB(string email)

        List<string[]> historicos = new List<string[]>();
        sql = "SELECT * FROM historico_verificacao_email WHERE nm_email = '" + email + "' ORDER BY  dt_verificacao_email DESC, hr_verificacao_email DESC"; 
        com = new SqlCommand(sql, conexao);
        SqlDataReader dr = com.ExecuteReader();

        if (dr.HasRows)
            while (dr.Read())
                string[] dados_historico = new string[6];
                dados_historico[0] = dr["nm_email"].ToString();
                dados_historico[1] = dr["dt_verificacao_email"].ToString();
                dados_historico[1] = dados_historico[1].Substring(0, 10);
                dados_historico[2] = dr["hr_verificacao_email"].ToString();
                dados_historico[3] = dr["ds_tipo_verificacao"].ToString();
                dados_historico[5] = dr["cd_login_usuario"].ToString();


            sql = "SELECT COUNT(e.cd_historico_verificacao_email) QT FROM emails_lidos e WHERE e.cd_historico_verificacao_email = '" + dr["cd_historico_verificacao_email"].ToString() + "'";
            tipo_sql = "seleção";
            com2 = new SqlCommand(sql, conexao);

            for(int i = 0 ; i < historicos.Count() ; i++)
                SqlDataReader dr3 = com2.ExecuteReader();
                while (dr3.Read())
                    historicos[i][4] = dr3["QT"].ToString(); //quantidade de emails lidos naquela verificação


        return historicos;

jQuery How to Get Element's Margin and Padding?

According to the jQuery documentation, shorthand CSS properties are not supported.

Depending on what you mean by "total padding", you may be able to do something like this:

var $img = $('img');
var paddT = $img.css('padding-top') + ' ' + $img.css('padding-right') + ' ' + $img.css('padding-bottom') + ' ' + $img.css('padding-left');

Get my phone number in android

If the function you called returns null, it means your phone number is not registered in your contact list.

If instead of the phone number you just need an unique number, you may use the sim card's serial number:

    TelephonyManager telemamanger = (TelephonyManager)getSystemService(Context.TELEPHONY_SERVICE);
    String getSimSerialNumber = telemamanger.getSimSerialNumber();  

How to convert milliseconds to "hh:mm:ss" format?

DateFormat df = new SimpleDateFormat("HH:mm:ss");
String formatted = df.format(aDateObject);

OnClick Send To Ajax

Tried and working. you are using,

<textarea name='Status'> </textarea>
<input type='button' onclick='UpdateStatus()' value='Status Update'>

I am using javascript , (don't know about php), use id ="status" in textarea like

<textarea name='Status' id="status"> </textarea>
<input type='button' onclick='UpdateStatus()' value='Status Update'>

then make a call to servlet sending the status to backend for updating using whatever strutucre(like MVC in java or anyother) you like, like this in your UI in script tag

function UpdateStatus(){

//make an ajax call and get status value using the same 'id'
var var1= document.getElementById("status").value;

        type:"GET",//or POST
                           //  (or whatever your url is)
        //can send multipledata like {data1:var1,data2:var2,data3:var3
        //can use dataType:'text/html' or 'json' if response type expected 
               // process on data
               alert("got response as "+"'"+responsedata+"'");



and jsp is like

the servlet will look like:   //webservlet("/zcvdzv") is just for url annotation

public class Testajax extends HttpServlet {
private static final long serialVersionUID = 1L;
public Testajax() {
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    // TODO Auto-generated method stub
    String data1=request.getParameter("data1");
    //do processing on datas pass in other java class to add to DB
    // i am adding or concatenate
    String data="i Got : "+"'"+data1+"' ";
    System.out.println(" data1 : "+data1+"\n data "+data);
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    // TODO Auto-generated method stub
    doGet(request, response);


Convert Linq Query Result to Dictionary

Use namespace

using System.Collections.Specialized;

Make instance of DataContext Class

LinqToSqlDataContext dc = new LinqToSqlDataContext();


OrderedDictionary dict = dc.TableName.ToDictionary(d => d.key, d => d.value);

In order to retrieve the values use namespace

   using System.Collections;

ICollection keyCollections = dict.Keys;
ICOllection valueCollections = dict.Values;

String[] myKeys = new String[dict.Count];
String[] myValues = new String[dict.Count];


for(int i=0; i<dict.Count; i++)
Console.WriteLine("Key: " + myKeys[i] + "Value: " + myValues[i]);

How to open Atom editor from command line in OS X?

For Windows 7 x64 with default Atom installation add this to your PATH


and restart any running consoles

(if you don't find Atom there - right-click Atom icon and navigate to Target)

enter image description here

Client to send SOAP request and receive response

As an alternative, and pretty close to debiasej approach. Since a SOAP request is just a HTTP request, you can simply perform a GET or POST using with HTTP client, but it's not mandatory to build SOAP envelope.

Something like this:

using Microsoft.Extensions.Logging;
using System;
using System.Net.Http;
using System.Text;
using System.Threading.Tasks;

namespace HGF.Infraestructure.Communications
    public class SOAPSample
        private readonly IHttpClientFactory _clientFactory;
        private readonly ILogger<DocumentProvider> _logger;

        public SOAPSample(ILogger<DocumentProvider> logger,
                          IHttpClientFactory clientFactory)
            _clientFactory = clientFactory;
            _logger = logger;

        public async Task<string> UsingGet(int value1, int value2)
                var client = _clientFactory.CreateClient();
                var response = await client.GetAsync($"{value1}&value2={value2}", HttpCompletionOption.ResponseHeadersRead);

                //NULL check, HTTP Status Check....

                return await response.Content.ReadAsStringAsync();
            catch (Exception ex)
                _logger.LogError(ex, "Oops! Something went wrong");
                return ex.Message;

        public async Task<string> UsingPost(int value1, int value2)
                var content = new StringContent($"value1={value1}&value2={value2}", Encoding.UTF8, "application/x-www-form-urlencoded");

                var client = _clientFactory.CreateClient();
                var response = await client.PostAsync("", content);

                //NULL check, HTTP Status Check....

                return await response.Content.ReadAsStringAsync();
            catch (Exception ex)
                _logger.LogError(ex, "Oops! Something went wrong");
                return ex.Message;

Of course, it depends on your scenario. If the payload is too complex, then this won't work

How to get href value using jQuery?

You need

var href = $(this).attr('href');

Inside a jQuery click handler, the this object refers to the element clicked, whereas in your case you're always getting the href for the first <a> on the page. This, incidentally, is why your example works but your real code doesn't

Jquery UI tooltip does not support html content

As long as we're using jQuery (> v1.8), we can parse the incoming string with $.parseHTML().

    content: function () {
        var tooltipContent = $('<div />').html( $.parseHTML( $(this).attr('title') ) );
        return tooltipContent;

We'll parse the incoming string's attribute for unpleasant things, then convert it back to jQuery-readable HTML. The beauty of this is that by the time it hits the parser the strings are already concatenates, so it doesn't matter if someone is trying to split the script tag into separate strings. If you're stuck using jQuery's tooltips, this appears to be a solid solution.

Creating and throwing new exception

You can throw your own custom errors by extending the Exception class.

class CustomException : Exception {
    [string] $additionalData

    CustomException($Message, $additionalData) : base($Message) {
        $this.additionalData = $additionalData

try {
    throw [CustomException]::new('Error message', 'Extra data')
} catch [CustomException] {
    # NOTE: To access your custom exception you must use $_.Exception
    Write-Output $_.Exception.additionalData

    # This will produce the error message: Didn't catch it the second time
    throw [CustomException]::new("Didn't catch it the second time", 'Extra data')

Figuring out whether a number is a Double in Java

Try this:

if (items.elementAt(1) instanceof Double) {
   sum.add( i, items.elementAt(1));

How to use range-based for() loop with std::map?

From this paper:

for( type-speci?er-seq simple-declarator : expression ) statement

is syntactically equivalent to

    typedef decltype(expression) C;
    auto&& rng(expression);
    for (auto begin(std::For<C>::begin(rng)), end(std::For<C>::end(rng)); begin != end; ++ begin) {
        type-speci?er-seq simple-declarator(*begin);

So you can clearly see that what is abc in your case will be std::pair<key_type, value_type >. So for printing you can do access each element by abc.first and abc.second

How can I generate a list of consecutive numbers?

Using Python's built in range function:

Python 2

input = 8
output = range(input + 1)

print output
[0, 1, 2, 3, 4, 5, 6, 7, 8]

Python 3

input = 8
output = list(range(input + 1))

[0, 1, 2, 3, 4, 5, 6, 7, 8]

MySQL vs MongoDB 1000 reads

Honestly even if MongoDB is slower, MongoDB definitely makes me and you code faster.... no need to worry about silly table columns, row or entity migrations...

With MongoDB, you just instantiate a class and save!

Using GregorianCalendar with SimpleDateFormat


    "23-Mar-2017" ,
    DateTimeFormatter.ofPattern( "dd-MMM-uuuu" , Locale.US ) 

Avoid legacy date-time classes

The Question and other Answers are now outdated, using troublesome old date-time classes that are now legacy, supplanted by the java.time classes.

Using java.time

You seem to be dealing with date-only values. So do not use a date-time class. Instead use LocalDate. The LocalDate class represents a date-only value without time-of-day and without time zone.

Specify a Locale to determine (a) the human language for translation of name of day, name of month, and such, and (b) the cultural norms deciding issues of abbreviation, capitalization, punctuation, separators, and such.

Parse a string.

String input = "23-Mar-2017" ;
DateTimeFormatter f = DateTimeFormatter.ofPattern( "dd-MMM-uuuu" , Locale.US ) ;
LocalDate ld = LocalDate.parse( input , f );

Generate a string.

String output = ld.format( f );

If you were given numbers rather than text for the year, month, and day-of-month, use LocalDate.of.

LocalDate ld = LocalDate.of( 2017 , 3 , 23 );  // ( year , month 1-12 , day-of-month )

See this code run live at

input: 23-Mar-2017

ld.toString(): 2017-03-23

output: 23-Mar-2017

About java.time

The java.time framework is built into Java 8 and later. These classes supplant the troublesome old legacy date-time classes such as java.util.Date, Calendar, & SimpleDateFormat.

The Joda-Time project, now in maintenance mode, advises migration to the java.time classes.

To learn more, see the Oracle Tutorial. And search Stack Overflow for many examples and explanations. Specification is JSR 310.

Using a JDBC driver compliant with JDBC 4.2 or later, you may exchange java.time objects directly with your database. No need for strings nor java.sql.* classes.

Where to obtain the java.time classes?

The ThreeTen-Extra project extends java.time with additional classes. This project is a proving ground for possible future additions to java.time. You may find some useful classes here such as Interval, YearWeek, YearQuarter, and more.

Linq select to new object

The answers here got me close, but in 2016, I was able to write the following LINQ:

List<ObjectType> objectList = similarTypeList.Select(o =>
    new ObjectType
        PropertyOne = o.PropertyOne,
        PropertyTwo = o.PropertyTwo,
        PropertyThree = o.PropertyThree

How can I read user input from the console?

You're missing a semicolon: double b = a * Math.PI;

Google Maps v3 - limit viewable area and zoom level

myOptions = {
        center: myLatlng,
        minZoom: 6,
        maxZoom: 9,
        styles: customStyles,
        mapTypeId: google.maps.MapTypeId.ROADMAP

What LaTeX Editor do you suggest for Linux?

I normally use Emacs (it has everything you need included).

Of course, there are other options available:

  • Kile is KDE's LaTeX editor; it's excellent if you're just learning or if you prefer the integrated environment approach;
  • Lyx is a WYSIWYG editor that uses LaTeX as a backend; i.e. you tell it what the text should look like and it generates the corresponding LaTeX


php search array key and get value

The key is already the ... ehm ... key

echo $array[20120504];

If you are unsure, if the key exists, test for it

$key = 20120504;
$result = isset($array[$key]) ? $array[$key] : null;

Minor addition:

$result = @$array[$key] ?: null;

One may argue, that @ is bad, but keep it serious: This is more readable and straight forward, isn't?

Update: With PHP7 my previous example is possible without the error-silencer

$result = $array[$key] ?? null;

Count unique values in a column in Excel

Count unique with a condition. Col A is ID and using condition ID=32, Col B is Name and we are trying to count the unique names for a particular ID


Make Https call using HttpClient

I agree with felickz but also i want to add an example for clarifying the usage in c#. I use SSL in windows service as follows.

    var certificatePath = System.IO.Path.Combine(System.AppDomain.CurrentDomain.BaseDirectory, "bin");
    gateway = new GatewayService();
    gateway.PreAuthenticate = true;

    X509Certificate2 cert = new X509Certificate2(certificatePath + @"\Attached\my_certificate.pfx","certificate_password");

    ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12;
    gateway.UserAgent = Guid.NewGuid().ToString();
    gateway.Timeout = int.MaxValue;

If I'm going to use it in a web application, I'm just changing the implementation on the proxy side like this:

public partial class GatewayService : System.Web.Services.Protocols.SoapHttpClientProtocol // to => Microsoft.Web.Services2.WebServicesClientProtocol

how to show alternate image if source image is not found? (onerror working in IE but not in mozilla)

I have got the solution for my query:

i have done something like this:

cell.innerHTML="<img height=40 width=40 alt='' src='<%=request.getContextPath()%>/writeImage.htm?' onerror='onImgError(this);' onLoad='setDefaultImage(this);'>"

function setDefaultImage(source){
        var badImg = new Image();
        badImg.src = "video.png";
        var cpyImg = new Image();
        cpyImg.src = source.src;

            source.src = badImg.src;


    function onImgError(source){
        source.src = "video.png";
        source.onerror = ""; 
        return true; 

This way it's working in all browsers.


In 2019 you can use querySelector for that.

It's supported by most browsers (


Can I pass a JavaScript variable to another browser window?

The function will also allow this if you have a reference to the window created, provided it is on the same domain. If the variable is used server side you should be using a $_SESSION variable (assuming you are using PHP).

Is Xamarin free in Visual Studio 2015?

If you go to the Visual Studio 2015 RC cross-platform and mobile apps page, then read and scroll to the bottom, it appears that Microsoft is including Xamarin, and upon installing it you do have, as James said, the Xamarin Starter edition. In 2015 RC go to Tools, Xamarin Account to see your Xamarin license. I do not know the limitations, or any expiration date, of this Starter Xamarin Account.

Still, I don't know about you, but the Visual Studio 2015 RC "Community" edition I installed expires in less than 180 days. (Check the Help menu, go to "About...", and click on your license status to check.)

Let's say Xamarin Starter edition is free, but Visual Studio 2015 "Community" has an expiration date. So the bigger question might be whether Visual Studio 2015 "Community" will be free.

Without Xamarin though, Microsoft is offering C++ tools for cross-platform development, but scroll down to the bottom of the page and you might be surprised or confused at the download link description.

Tomcat 7: How to set initial heap size correctly?

You might no need to having export, just add this line in :

CATALINA_OPTS="-Xms512M -Xmx1024M"

Why is sed not recognizing \t as a tab?

Using Bash you may insert a TAB character programmatically like so:

echo 'line' | sed "s/.*/${TAB}&/g" 
echo 'line' | sed 's/.*/'"${TAB}"'&/g'   # use of Bash string concatenation

How to filter specific apps for ACTION_SEND intent (and set a different text for each app)

This solution shows a list of applications in a ListView dialog that resembles the chooser:


It is up to you to:

  1. obtain the list of relevant application packages
  2. given a package name, invoke the relevant intent

The adapter class:

import java.util.List;

import android.content.Context;
import android.util.TypedValue;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.TextView;

public class ChooserArrayAdapter extends ArrayAdapter<String> {
    PackageManager mPm;
    int mTextViewResourceId;
    List<String> mPackages;

    public ChooserArrayAdapter(Context context, int resource, int textViewResourceId, List<String> packages) {
        super(context, resource, textViewResourceId, packages);
        mPm = context.getPackageManager();
        mTextViewResourceId = textViewResourceId;
        mPackages = packages;

    public View getView(int position, View convertView, ViewGroup parent) {
        String pkg = mPackages.get(position);
        View view = super.getView(position, convertView, parent);

        try {
            ApplicationInfo ai = mPm.getApplicationInfo(pkg, 0);

            CharSequence appName = mPm.getApplicationLabel(ai);
            Drawable appIcon = mPm.getApplicationIcon(pkg);

            TextView textView = (TextView) view.findViewById(mTextViewResourceId);
            textView.setCompoundDrawablesWithIntrinsicBounds(appIcon, null, null, null);
            textView.setCompoundDrawablePadding((int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 12, getContext().getResources().getDisplayMetrics()));
        } catch (NameNotFoundException e) {

        return view;


and its usage:

    void doXxxButton() {
        final List<String> packages = ...;
        if (packages.size() > 1) {
            ArrayAdapter<String> adapter = new ChooserArrayAdapter(MyActivity.this, android.R.layout.select_dialog_item,, packages);

            new AlertDialog.Builder(MyActivity.this)
            .setAdapter(adapter, new DialogInterface.OnClickListener() {
                public void onClick(DialogInterface dialog, int item ) {
        } else if (packages.size() == 1) {

    void invokeApplication(String packageName) {
        // given a package name, create an intent and fill it with data
        startActivityForResult(intent, rq);

Multiline input form field using Bootstrap

The answer by Nick Mitchinson is for Bootstrap version 2.

If you are using Bootstrap version 3, then forms have changed a bit. For bootstrap 3, use the following instead:

<div class="form-horizontal">
    <div class="form-group">
        <div class="col-md-6">
            <textarea class="form-control" rows="3" placeholder="What's up?" required></textarea>

Where, col-md-6 will target medium sized devices. You can add col-xs-6 etc to target smaller devices.

Pandas: Subtracting two date columns and the result being an integer

Create a vectorized method

def calc_xb_minus_xa(df):
    time_dict = {
        '<Minute>': 'm',
        '<Hour>': 'h',
        '<Day>': 'D',
        '<Week>': 'W',
        '<Month>': 'M',
        '<Year>': 'Y'

    time_delta =[df.index[0], 'end_time'] -[df.index[0], 'open_time']
    offset_base_name = str(to_offset(time_delta).base)
    time_term = time_dict.get(offset_base_name)

    result = (df.end_time - df.open_time) / np.timedelta64(1, time_term)
    return result

Then in your df do:

df['x'] = calc_xb_minus_xa(df)

This will work for minutes, hours, days, weeks, month and Year. open_time and end_time need to change according your df

Decreasing for loops in Python impossible?

Late to the party, but for anyone tasked with creating their own or wants to see how this would work, here's the function with an added bonus of rearranging the start-stop values based on the desired increment:

def RANGE(start, stop=None, increment=1):
    if stop is None:
        stop = start
        start = 1

    value_list = sorted([start, stop])

    if increment == 0:
        print('Error! Please enter nonzero increment value!')
        value_list = sorted([start, stop])
        if increment < 0:
            start = value_list[1]
            stop = value_list[0]
            while start >= stop:
                worker = start
                start += increment
                yield worker
            start = value_list[0]
            stop = value_list[1]
            while start < stop:
                worker = start
                start += increment
                yield worker

Negative increment:

for i in RANGE(1, 10, -1):

Or, with start-stop reversed:

for i in RANGE(10, 1, -1):



Regular increment:

for i in RANGE(1, 10):



Zero increment:

for i in RANGE(1, 10, 0):


'Error! Please enter nonzero increment value!'

How to BULK INSERT a file into a *temporary* table where the filename is a variable?

Sorry to dig up an old question but in case someone stumbles onto this thread and wants a quicker solution.

Bulk inserting a unknown width file with \n row terminators into a temp table that is created outside of the EXEC statement.


    DROP TABLE #BulkInsert

    Line    VARCHAR(MAX)


SELECT * FROM #BulkInsert

Further support that dynamic SQL within an EXEC statement has access to temp tables outside of the EXEC statement.!3/d41d8/19343


    DROP TABLE #BulkInsert

    Line    VARCHAR(MAX)

SET @SQL = 'SELECT * FROM #BulkInsert'

Further support, written for MSSQL2000

Example at the bottom of the link

DECLARE @cmd VARCHAR(1000), @ExecError INT
CREATE TABLE #ErrFile (ExecError INT)
SET @cmd = 'EXEC GetTableCount ' + 
'''pubs.dbo.authors''' + 
SET @ExecError = (SELECT * FROM #ErrFile)
SELECT @ExecError AS '@@ERROR'

How to pass form input value to php function

you must have read about function call . here i give you example of it.

 funtion pr($n)
echo $n;
<form action="<?php $f=$_POST['input'];pr($f);?>" method="POST">
<input name=input type=text></input>

How to use Python to execute a cURL command?

curl -d @request.json --header "Content-Type: application/json"

its python implementation be like

import requests

headers = {
    'Content-Type': 'application/json',

params = (
    ('key', 'mykeyhere'),

data = open('request.json')
response ='', headers=headers, params=params, data=data)

#NB. Original query string below. It seems impossible to parse and
#reproduce query strings 100% accurately so the one below is given
#in case the reproduced version is not "correct".
# response ='', headers=headers, data=data)

check this link, it will help convert cURl command to python,php and nodejs

Access elements in json object like an array

I found a straight forward way of solving this, with the use of JSON.parse.

Let's assume the json below is inside the variable jsontext.

  ["Blankaholm", "Gamleby"],
  ["2012-10-23", "2012-10-22"],
  ["Blankaholm. Under natten har det varit inbrott", "E22 i med Gamleby. Singelolycka. En bilist har.],
  ["57.586174","16.521841"], ["57.893162","16.406090"]

The solution is this:

var parsedData = JSON.parse(jsontext);

Now I can access the elements the following way:

var cities = parsedData[0];

HTML img tag: title attribute vs. alt attribute?

ALT Attribute

The alt attribute is defined in a set of tags (namely, img, area and optionally for input and applet) to allow you to provide a text equivalent for the object.

A text equivalent brings the following benefits to your web site and its visitors in the following common situations:

  • nowadays, Web browsers are available in a very wide variety of platforms with very different capacities; some cannot display images at all or only a restricted set of type of images; some can be configured to not load images. If your code has the alt attribute set in its images, most of these browsers will display the description you gave instead of the images
  • some of your visitors cannot see images, be they blind, color-blind, low-sighted; the alt attribute is of great help for those people that can rely on it to have a good idea of what's on your page
  • search engine bots belong to the two above categories: if you want your website to be indexed as well as it deserves, use the alt attribute to make sure that they won't miss important sections of your pages.

Title Attribute

The objective of this technique is to provide context sensitive help for users as they enter data in forms by providing the help information in a title attribute. The help may include format information or examples of input.

Example 1: A pulldown menu that limits the scope of a search
A search form uses a pulldown menu to limit the scope of the search. The pulldown menu is immediately adjacent to the text field used to enter the search term. The relationship between the search field and the pulldown menu is clear to users who can see the visual design, which does not have room for a visible label. The title attribute is used to identify the select menu. The title attribute can be spoken by screen readers or displayed as a tool tip for people using screen magnifiers.

<label for="searchTerm">Search for:</label>
<input id="searchTerm" type="text" size="30" value="" name="searchTerm">
<select title="Search in" id="scope">

Example 2: Input fields for a phone number
A Web page contains controls for entering a phone number in the United States, with three fields for area code, exchange, and last four digits.

    <legend>Phone number</legend>
    <input id="areaCode" name="areaCode" title="Area Code" type="text" size="3" value="" >
    <input id="exchange" name="exchange" title="First three digits of phone number" type="text" size="3" value="" >
    <input id="lastDigits" name="lastDigits" title="Last four digits of phone number" type="text" size="4" value="" >

Example 3: A Search Function A Web page contains a text field where the user can enter search terms and a button labeled "Search" for performing the search. The title attribute is used to identify the form control and the button is positioned right after the text field so that it is clear to the user that the text field is where the search term should be entered.

<input type="text" title="Type search term here"/> <input type="submit" value="Search"/>

Example 4: A data table of form controls
A data table of form controls needs to associate each control with the column and row headers for that cell. Without a title (or off-screen LABEL) it is difficult for non-visual users to pause and interrogate for corresponding row/column header values using their assistive technology while tabbing through the form.

For example, a survey form has four column headers in first row: Question, Agree, Undecided, Disagree. Each following row contains a question and a radio button in each cell corresponding to answer choice in the three columns. The title attribute for every radio button is a concatenation of the answer choice (column header) and the text of the question (row header) with a hyphen or colon as a separator.

Img Element

Allowed attributes mentioned at MDN.

  • alt
  • crossorigin
  • decoding
  • height
  • importance (experimental api)
  • intrinsicsize (experimental api)
  • ismap
  • referrerpolicy (experimental api)
  • src
  • srcset
  • width
  • usemap

As you can see title attribute is not allowed inside img element. I would use alt attribute and if requires I would use CSS (Example: pseudo class :hover) instead of title attribute.

Vertical Menu in Bootstrap

here is vertical menu base on Bootstrap it is also support responsive design.

How to read an external properties file in Maven

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


Check if file is already open

Using the Apache Commons IO library...

boolean isFileUnlocked = false;
try {;
    isFileUnlocked = true;
} catch (IOException e) {
    isFileUnlocked = false;

    // Do stuff you need to do with a file that is NOT locked.
} else {
    // Do stuff you need to do with a file that IS locked

View's SELECT contains a subquery in the FROM clause

create view view_clients_credit_usage as
    select client_id, sum(credits_used) as credits_used 
    from credit_usage 
    group by client_id

create view view_credit_status as 
        sum(credit_orders.number_of_credits) as purchased, 
        ifnull(t1.credits_used,0) as used 
    from credit_orders
    left outer join view_clients_credit_usage as t1 on t1.client_id = credit_orders.client_id
    where credit_orders.payment_status='Paid'
    group by credit_orders.client_id)

Mysql - delete from multiple tables with one query

Apparently, it is possible. From the manual:

You can specify multiple tables in a DELETE statement to delete rows from one or more tables depending on the particular condition in the WHERE clause. However, you cannot use ORDER BY or LIMIT in a multiple-table DELETE. The table_references clause lists the tables involved in the join. Its syntax is described in Section, “JOIN Syntax”.

The example in the manual is:


should be applicable 1:1.

Ajax post request in laravel 5 return error 500 (Internal Server Error)

90% of the laravel ajax internal server error is due to missing CSRF token. other reasons can inlucde:

  • Wrong Request Type (e.g sending post to get)
  • Wrong data type recived (e.g ajax is expecting JSON and app returns string)
  • Your .htaccess is misconfigured
  • Missing Route
  • Code Error

You can read further about this in details here:

Get data from php array - AJAX - jQuery

quite possibly the simplest method ...

$change = array('key1' => $var1, 'key2' => $var2, 'key3' => $var3);
echo json_encode(change);

Then the jquery script ...

$.get("location.php", function(data){
var duce = jQuery.parseJSON(data);
var art1 = duce.key1;
var art2 = duce.key2;
var art3 = duce.key3;

Play audio file from the assets directory

this works for me:

public static class eSound_Def
  private static Android.Media.MediaPlayer mpBeep;

  public static void InitSounds( Android.Content.Res.AssetManager Assets )
    mpBeep = new Android.Media.MediaPlayer();

    InitSound_Beep( Assets );

  private static void InitSound_Beep( Android.Content.Res.AssetManager Assets )
    Android.Content.Res.AssetFileDescriptor AFD;

    AFD = Assets.OpenFd( "Sounds/beep-06.mp3" );
    mpBeep.SetDataSource( AFD.FileDescriptor, AFD.StartOffset, AFD.Length );

    mpBeep.SetVolume( 1f, 1f );
    mpBeep.Looping = false;

  public static void PlaySound_Beep()
    if (mpBeep.IsPlaying == true) 

In main activity, on create:

protected override void OnCreate( Bundle savedInstanceState )
  base.OnCreate( savedInstanceState );
  SetContentView( Resource.Layout.lmain_activity );
  eSound_Def.InitSounds( Assets );

how to use in code (on button click):

private void bButton_Click( object sender, EventArgs e )

How can I ask the Selenium-WebDriver to wait for few seconds in Java?


is the worse: being a static wait, it will make test script slower.


this is a dynamic wait

  • it is valid till webdriver existence or has a scope till driver lifetime
  • we can implicit wait also.

Finally, what I suggest is

WebDriverWait wait = new WebDriverWait(driver,20);
wait.until(ExpectedConditions.<different canned or predefined conditions are there>);

with some predefined conditions:

  • It is also dynamic wait
  • in this the wait will only be in seconds
  • we have to use explicit wait for a particular web element on which we want to use.

How can I make a list of lists in R?

Using your example::

list1 <- list()
list1[1] = 1
list1[2] = 2
list2 <- list()
list2[1] = 'a'
list2[2] = 'b'
list_all <- list(list1, list2)

Use '[[' to retrieve an element of a list:

b = list_all[[1]]
[1] 1

[1] 2

[1] "list"

Split a string by a delimiter in python

You can use the str.split method: string.split('__')

>>> "MATCHES__STRING".split("__")

Count the number of all words in a string

Most simple way would be:

str_count("one,   two three 4,,,, 5 6", "\\S+")

... counting all sequences on non-space characters (\\S+).

But what about a little function that lets us also decide which kind of words we would like to count and which works on whole vectors as well?

nwords <- function(string, pseudo=F){
  ifelse( pseudo, 
          pattern <- "\\S+", 
          pattern <- "[[:alpha:]]+" 
  str_count(string, pattern)

nwords("one,   two three 4,,,, 5 6")
# 3

nwords("one,   two three 4,,,, 5 6", pseudo=T)
# 6

Jquery .on('scroll') not firing the event while scrolling

Can you place the #ulId in the document prior to the ajax load (with css display: none;), or wrap it in a containing div (with css display: none;), then just load the inner html during ajax page load, that way the scroll event will be linked to the div that is already there prior to the ajax?

Then you can use:

$('#ulId').on('scroll',function(){ console.log('Event Fired'); })

obviously replacing ulId with whatever the actual id of the scrollable div is.

Then set css display: block; on the #ulId (or containing div) upon load?

Easiest way to loop through a filtered list with VBA?

a = 2
x = 0

Do Until Cells(a, 1).Value = ""
If Rows(a).Hidden = False Then
x = Cells(a, 1).Value + x
End If
a = a + 1

End Sub

XSLT equivalent for JSON

To say lack of tools suggest lack of need is just begging the question. The same could be applied to support for X or Y in Linux (Why bother developing quality drivers and/or games for such a minority OS? And why pay attention to an OS that big game and hardware companies don't develop for?). Probably the people who would need to use XSLT and JSON end up using a somewhat trivial workaround: Transforming JSON into XML. But that's not the optimal solution, is it?

When you have a native JSON format and you want to edit it "wysywyg" in the browser, XSLT would be a more than adequate solution for the problem. Doing that with traditional javascript programming can become a pain in the arse.

In fact, I have implemented a "stone-age" approach to XSLT, using substring parsing to interpret some basic commands for javascript, like calling a template, process children, etc. Certainly implementing a transformation engine with a JSON object is much easier than implementing a full-fledged XML parser to parse the XSLT. Problem is, that to use XML templates to transform a JSON object you need to parse the XML of the templates.

To tranform a JSON object with XML (or HTML, or text or whatever) you need to think carefully about the syntax and what special characters you need to use to identify the transformation commands. Otherwise you'll end up having to design a parser for your own custom templating language. Having walked through that path, I can tell you that it's not pretty.

Update (Nov 12, 2010): After a couple of weeks working on my parser, I've been able to optimize it. Templates are parsed beforehand and commands are stored as JSON objects. Transformation rules are also JSON objects, while the template code is a mix of HTML and a homebrew syntax similar to shell code. I've been able to transform a complex JSON document into HTML to make a document editor. The code is around 1K lines for the editor (it's for a private project so I can't share it) and around 990 lines for the JSON transformation code (includes iteration commands, simple comparisons, template calling, variable saving and evaluation). I plan to release it under a MIT license. Drop me a mail if you want to get involved.

Can't bind to 'ngIf' since it isn't a known property of 'div'

If you are using RC5 then import this:

import { CommonModule } from '@angular/common';  
import { BrowserModule } from '@angular/platform-browser';

and be sure to import CommonModule from the module that is providing your component.

    imports: [CommonModule],
    declarations: [MyComponent]
class MyComponentModule {}

Accessing attributes from an AngularJS directive

Although using '@' is more appropriate than using '=' for your particular scenario, sometimes I use '=' so that I don't have to remember to use attrs.$observe():

<su-label tooltip="field.su_documentation">{{field.su_name}}</su-label>


myApp.directive('suLabel', function() {
    return {
        restrict: 'E',
        replace: true,
        transclude: true,
        scope: {
            title: '=tooltip'
        template: '<label><a href="#" rel="tooltip" title="{{title}}" data-placement="right" ng-transclude></a></label>',
        link: function(scope, element, attrs) {
            if (scope.title) {


With '=' we get two-way databinding, so care must be taken to ensure scope.title is not accidentally modified in the directive. The advantage is that during the linking phase, the local scope property (scope.title) is defined.

How to save a data.frame in R?

If you are only saving a single object (your data frame), you could also use saveRDS.
To save:

saveRDS(foo, file="data.Rda")

Then read it with:

bar <- readRDS(file="data.Rda")

The difference between saveRDS and save is that in the former only one object can be saved and the name of the object is not forced to be the same after you load it.

Creating an Arraylist of Objects

ArrayList<Matrices> list = new ArrayList<Matrices>();
list.add( new Matrices(1,1,10) );
list.add( new Matrices(1,2,20) );

Rails formatting date

Since I18n is the Rails core feature starting from version 2.2 you can use its localize-method. By applying the forementioned strftime %-variables you can specify the desired format under config/locales/en.yml (or whatever language), in your case like this:

    default: '%FT%T'

Or if you want to use this kind of format in a few specific places you can refer it as a variable like this

    specific_format: '%FT%T'

After that you can use it in your views like this:

l(Mode.last.created_at, format: :specific_format)  

Renaming part of a filename

Something like this will do it. The for loop may need to be modified depending on which filenames you wish to capture.

for fspec1 in DET01-ABC-5_50-*.dat ; do
    fspec2=$(echo ${fspec1} | sed 's/-ABC-/-XYZ-/')
    mv ${fspec1} ${fspec2}

You should always test these scripts on copies of your data, by the way, and in totally different directories.

SQL 'like' vs '=' performance

You are asking the wrong question. In databases is not the operator performance that matters, is always the SARGability of the expression, and the coverability of the overall query. Performance of the operator itself is largely irrelevant.

So, how do LIKE and = compare in terms of SARGability? LIKE, when used with an expression that does not start with a constant (eg. when used LIKE '%something') is by definition non-SARGabale. But does that make = or LIKE 'something%' SARGable? No. As with any question about SQL performance the answer does not lie with the query of the text, but with the schema deployed. These expression may be SARGable if an index exists to satisfy them.

So, truth be told, there are small differences between = and LIKE. But asking whether one operator or other operator is 'faster' in SQL is like asking 'What goes faster, a red car or a blue car?'. You should eb asking questions about the engine size and vechicle weight, not about the color... To approach questions about optimizing relational tables, the place to look is your indexes and your expressions in the WHERE clause (and other clauses, but it usually starts with the WHERE).

Counting number of occurrences in column?

Put the following in B3 (credit to @Alexander-Ivanov for the countif condition):


Benefits: It only requires editing 1 cell, it includes the name filtered by uniqueness, and it is concise.

Downside: it runs the unique function 3x

To use the unique function only once, split it into 2 cells:



List of Java processes

If I want simply list java processes, use:

ps -A | grep java

Remove json element

var json = { ... };
var key = "foo";
delete json[key]; // Removes from the dictionary.

You can use splice to remove elements from an array.

Python object deleting itself

I am trying the same thing. I have a RPG battle system in which my Death(self) function has to kill the own object of the Fighter class. But it appeared it`s not possible. Maybe my class Game in which I collect all participants in the combat should delete units form the "fictional" map???

   def Death(self):
    if self.stats["HP"] <= 0:
        print("%s wounds were too much... Dead!"%(self.player["Name"]))
        del self
        return True

def Damage(self, enemy):
    todamage = self.stats["ATK"] + randint(1,6)
    todamage -= enemy.stats["DEF"]
    if todamage >=0:
        enemy.stats["HP"] -= todamage
        print("%s took %d damage from your attack!"%(enemy.player["Name"], todamage))
        return True
        return True
def Attack(self, enemy):
    tohit = self.stats["DEX"] + randint(1,6)
    if tohit > enemy.stats["EVA"]:
        print("You landed a successful attack on %s "%(enemy.player["Name"]))
        return True
        return True
def Action(self, enemylist):
    for i in range(0, len(enemylist)):
        print("No.%d, %r"%(i, enemylist[i]))
    print("It`s your turn, %s. Take action!"%(self.player["Name"]))
    choice = input("\n(A)ttack\n(D)efend\n(S)kill\n(I)tem\n(H)elp\n>")
    if choice == 'a'or choice == 'A':
        who = int(input("Who? "))
        return True
        return self.Action()

Deleting all files in a directory with Python

Via os.listdir and os.remove:

import os

filelist = [ f for f in os.listdir(mydir) if f.endswith(".bak") ]
for f in filelist:
    os.remove(os.path.join(mydir, f))

Using only a single loop:

for f in os.listdir(mydir):
    if not f.endswith(".bak"):
    os.remove(os.path.join(mydir, f))

Or via glob.glob:

import glob, os, os.path

filelist = glob.glob(os.path.join(mydir, "*.bak"))
for f in filelist:

Be sure to be in the correct directory, eventually using os.chdir.

How to read the value of a private field from a different class in Java?

You can use Manifold's @JailBreak for direct, type-safe Java reflection:

@JailBreak Foo foo = new Foo();
foo.stuffIWant = "123;

public class Foo {
    private String stuffIWant;

@JailBreak unlocks the foo local variable in the compiler for direct access to all the members in Foo's hierarchy.

Similarly you can use the jailbreak() extension method for one-off use:

foo.jailbreak().stuffIWant = "123";

Through the jailbreak() method you can access any member in Foo's hierarchy.

In both cases the compiler resolves the field access for you type-safely, as if a public field, while Manifold generates efficient reflection code for you under the hood.

Discover more about Manifold.

Split String into an array of String

String[] result = "hi i'm paul".split("\\s+"); to split across one or more cases.

Or you could take a look at Apache Common StringUtils. It has StringUtils.split(String str) method that splits string using white space as delimiter. It also has other useful utility methods

Failed to load ApplicationContext (with annotation)

Your test requires a ServletContext: add @WebIntegrationTest

@ContextConfiguration(classes = AppConfig.class, loader = AnnotationConfigContextLoader.class)
public class UserServiceImplIT

...or look here for other options:

UPDATE In Spring Boot 1.4.x and above @WebIntegrationTest is no longer preferred. @SpringBootTest or @WebMvcTest

Can You Get A Users Local LAN IP Address Via JavaScript?

function getUserIP(onNewIP) { //  onNewIp - your listener function for new IPs_x000D_
  //compatibility for firefox and chrome_x000D_
  var myPeerConnection = window.RTCPeerConnection || window.mozRTCPeerConnection || window.webkitRTCPeerConnection;_x000D_
  var pc = new myPeerConnection({_x000D_
      iceServers: []_x000D_
    noop = function() {},_x000D_
    localIPs = {},_x000D_
    ipRegex = /([0-9]{1,3}(\.[0-9]{1,3}){3}|[a-f0-9]{1,4}(:[a-f0-9]{1,4}){7})/g,_x000D_
  function iterateIP(ip) {_x000D_
    if (!localIPs[ip]) onNewIP(ip);_x000D_
    localIPs[ip] = true;_x000D_
  //create a bogus data channel_x000D_
  // create offer and set local description_x000D_
  pc.createOffer().then(function(sdp) {_x000D_
    sdp.sdp.split('\n').forEach(function(line) {_x000D_
      if (line.indexOf('candidate') < 0) return;_x000D_
    pc.setLocalDescription(sdp, noop, noop);_x000D_
  }).catch(function(reason) {_x000D_
    // An error occurred, so handle the failure to connect_x000D_
  //listen for candidate events_x000D_
  pc.onicecandidate = function(ice) {_x000D_
    if (!ice || !ice.candidate || !ice.candidate.candidate || !ice.candidate.candidate.match(ipRegex)) return;_x000D_

How to insert new row to database with AUTO_INCREMENT column without specifying column names?

Just add the column names, yes you can use Null instead but is is a very bad idea to not use column names in any insert, ever.

Pytesseract : "TesseractNotFound Error: tesseract is not installed or it's not in your path", how do I fix this?

On Windows 64 bits, just add the following to the PATH environment variable: "C:\Program Files\Tesseract-OCR" and it will work.

Get Unix timestamp with C++

I created a global define with more information:

#include <iostream>
#include <ctime>
#include <iomanip>

#define __FILENAME__ (__builtin_strrchr(__FILE__, '/') ? __builtin_strrchr(__FILE__, '/') + 1 : __FILE__)    // only show filename and not it's path (less clutter)
#define INFO std::cout << std::put_time(std::localtime(&time_now), "%y-%m-%d %OH:%OM:%OS") << " [INFO] " << __FILENAME__ << "(" << __FUNCTION__ << ":" << __LINE__ << ") >> "
#define ERROR std::cout << std::put_time(std::localtime(&time_now), "%y-%m-%d %OH:%OM:%OS") << " [ERROR] " << __FILENAME__ << "(" << __FUNCTION__ << ":" << __LINE__ << ") >> "

static std::time_t time_now = std::time(nullptr);

Use it like this:

INFO << "Hello world" << std::endl;
ERROR << "Goodbye world" << std::endl;

Sample output:

16-06-23 21:33:19 [INFO] main.cpp(main:6) >> Hello world
16-06-23 21:33:19 [ERROR] main.cpp(main:7) >> Goodbye world

Put these lines in your header file. I find this very useful for debugging, etc.

WorksheetFunction.CountA - not working post upgrade to Office 2010

I'm not sure exactly what your problem is, because I cannot get your code to work as written. Two things seem evident:

  1. It appears you are relying on VBA to determine variable types and modify accordingly. This can get confusing if you are not careful, because VBA may assign a variable type you did not intend. In your code, a type of Range should be assigned to myRange. Since a Range type is an object in VBA it needs to be Set, like this: Set myRange = Range("A:A")
  2. Your use of the worksheet function CountA() should be called with .WorksheetFunction

If you are not doing it already, consider using the Option Explicit option at the top of your module, and typing your variables with Dim statements, as I have done below.

The following code works for me in 2010. Hopefully it works for you too:

Dim myRange As Range
Dim NumRows As Integer

Set myRange = Range("A:A")
NumRows = Application.WorksheetFunction.CountA(myRange)

Good Luck.

how to loop through json array in jquery?

try this

var events = [];

var obj = jQuery.parseJSON(doc);

     $.each(obj, function (key, value) {



Send HTML in email via PHP

Use PHPMailer,

To send HTML mail you have to set $mail->isHTML() only, and you can set your body with HTML tags

Here is a well written tutorial :

Online PHP syntax checker / validator

Here is also a good and simple site to check your php codes and share your code with fiends :

Circular gradient in android

I guess you should add android:centerColor

<shape xmlns:android=""
  android:angle="0" />

This example displays a horizontal gradient from white to black to white.

How to downgrade php from 7.1.1 to 5.6 in xampp 7.1.1?

This solution is Only for local system / localhost on windows:

The simplest way to install xampp 5.6.X version as per your requirement in other windows drive then run xampp 5.6.X services from it's control panel for php 5.6 version.

NOTE: If you already have xampp (any other version) on your system then please close that xampp's services then start xampp 5.6.x services otherwise this solution will not work.

You can download your required (xampp 5.6 as per question) xampp version from below link:

I have used this solution many times, it worked like charm. I hope this will also help you. Thank you to ask this question.

Vibrate and Sound defaults on notification

Some dummy codes might help you.

   private static NotificationCompat.Builder buildNotificationCommon(Context _context, .....) {
            NotificationCompat.Builder builder = new NotificationCompat.Builder(_context)
        builder.setVibrate(new long[] { 1000, 1000, 1000, 1000, 1000 });

        builder.setLights(Color.RED, 3000, 3000);


    return builder;

Add below permission for Vibration in AndroidManifest.xml file

<uses-permission android:name="android.permission.VIBRATE" />

JavaScript REST client Library

You can use which has

  1. Rest API support
  2. Built in support for many sites google, facebook, dropbox
  3. It supports oAuth 1 and 2 support.

Android Fragment onClick button Method

Another option may be to have your fragment implement View.OnClickListener and override onClick(View v) within your fragment. If you need to have your fragment talk to the activity simply add an interface with desired method(s) and have the activity implement the interface and override its method(s).

public class FragName extends Fragment implements View.OnClickListener { 
    public FragmentCommunicator fComm;
    public ImageButton res1, res2;
    int c;

    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        return inflater.inflate(R.layout.fragment_test, container, false);

    public void onAttach(Activity activity) {
        try {
            fComm = (FragmentCommunicator) activity;
        } catch (ClassCastException e) {
            throw new ClassCastException(activity.toString()
                    + " must implement FragmentCommunicator");

    public void onActivityCreated(Bundle savedInstanceState) {
        res1 = (ImageButton) getActivity().findViewById(;
        res2 = (ImageButton) getActivity().findViewById(;
    public void onClick(final View v) { //check for what button is pressed
            switch (v.getId()) {
                  c *= fComm.fragmentContactActivity(2);
                  c *= fComm.fragmentContactActivity(4);
                  c *= fComm.fragmentContactActivity(100);
    public interface FragmentCommunicator{
        public int fragmentContactActivity(int b);

public class MainActivity extends FragmentActivity implements FragName.FragmentCommunicator{
    int a = 10;
    //variable a is update by fragment. ex. use to change textview or whatever else you'd like.

    public int fragmentContactActivity(int b) {
        //update info on activity here
        a += b;
        return a;

Python conversion from binary string to hexadecimal

Assuming they are grouped by 4 and separated by whitespace. This preserves the leading 0.

b = '0000 0100 1000 1101'
h = ''.join(hex(int(a, 2))[2:] for a in b.split())

Facebook share link without JavaScript

Ps 2: As pointed out by Justin, check out Facebook's new Share Dialog. Will leave the answer as is for posterity. This answer is obsolete

Short answer, yes there's a similar option for Facebook, that doesn't require javascript (well, there's some minimal inline JS that is not compulsory, see note).

Ps: The onclick part only helps you customise the popup a little bit but is not required for the code to work ... it will work just fine without it.


<a href=""
   onclick=", '', 'menubar=no,toolbar=no,resizable=yes,scrollbars=yes,height=300,width=600');return false;"
   target="_blank" title="Share on Facebook">


<a href=""
   onclick=", '', 'menubar=no,toolbar=no,resizable=yes,scrollbars=yes,height=300,width=600');return false;"
   target="_blank" title="Share on Twitter">

Jquery - Uncaught TypeError: Cannot use 'in' operator to search for '324' in

Use getJSON

    $.each(data, function(key, value){
        console.log(key + ":" + value)

Detail look here

Why javascript getTime() is not a function?

For all those who came here and did indeed use Date typed Variables, here is the solution I found. It does also apply to TypeScript.

I was facing this error because I tried to compare two dates using the following Method

var res = dat1.getTime() > dat2.getTime(); // or any other comparison operator

However Im sure I used a Date object, because Im using angularjs with typescript, and I got the data from a typed API call.

Im not sure why the error is raised, but I assume that because my Object was created by JSON deserialisation, possibly the getTime() method was simply not added to the prototype.


In this case, recreating a date-Object based on your dates will fix the issue.

var res = new Date(dat1).getTime() > new Date(dat2).getTime()


I was right about this. Types will be cast to the according type but they wont be instanciated. Hence there will be a string cast to a date, which will obviously result in a runtime exception.

The trick is, if you use interfaces with non primitive only data such as dates or functions, you will need to perform a mapping after your http request.

class Details {
    description: string;
    date: Date;
    score: number;
    approved: boolean;

    constructor(data: any) {
      Object.assign(this, data);

and to perform the mapping:

public getDetails(id: number): Promise<Details> {
    return this.http
               .map(response => new Details(response.json()))

for arrays use:

public getDetails(): Promise<Details[]> {
    return this.http
               .map(response => {
                   const array = JSON.parse(response.json()) as any[];
                   const details = => new Details(data));
                   return details;

For credits and further information about this topic follow the link.

Typescript empty object for a typed variable

you can do this as below in typescript

 const _params = {} as any; ='nazeh abel'

since typescript does not behave like javascript so we have to make the type as any otherwise it won't allow you to assign property dynamically to an object

setAttribute('display','none') not working

display is not an attribute - it's a CSS property. You need to access the style object for this:

document.getElementById('classRight').style.display = 'none';

How to initialize private static members in C++?

For a variable:


class foo
    static int i;


int foo::i = 0;

This is because there can only be one instance of foo::i in your program. It's sort of the equivalent of extern int i in a header file and int i in a source file.

For a constant you can put the value straight in the class declaration:

class foo
    static int i;
    const static int a = 42;

Get MAC address using shell script

Here's an alternative answer in case the ones listed above don't work for you. You can use the following solution(s) as well, which was found here:

ip addr


ip addr show


ip link

All three of these will show your MAC address(es) next to link/ether. I stumbled on this because I had just done a fresh install of Debian 9.5 from a USB stick without internet access, so I could only do a very minimal install, and received

-bash: ifconfig: command not found

when I tried some of the above solutions. I figured somebody else may come across this problem as well. Hope it helps.

Plot size and resolution with R markdown, knitr, pandoc, beamer

Figure sizes are specified in inches and can be included as a global option of the document output format. For example:

title: "My Document"
    fig_width: 6
    fig_height: 4

And the plot's size in the graphic device can be increased at the chunk level:

```{r, fig.width=14, fig.height=12}          #Expand the plot width to 14 inches

ggplot(aes(x=mycolumn1, y=mycolumn2)) +     #specify the x and y aesthetic
geom_line(size=2) +                         #makes the line thicker
theme_grey(base_size = 25)                  #increases the size of the font

You can also use the out.width and out.height arguments to directly define the size of the plot in the output file:

```{r, out.width="200px", out.height="200px"} #Expand the plot width to 200 pixels

ggplot(aes(x=mycolumn1, y=mycolumn2)) +     #specify the x and y aesthetic
geom_line(size=2) +                         #makes the line thicker
theme_grey(base_size = 25)                  #increases the size of the font

PHP date add 5 year to current date

try this:

$yearnow= date("Y");
echo date("Y")."-".$yearnext;

How to Implement Custom Table View Section Headers and Footers with Storyboard

I got it working in iOS7 using a prototype cell in the storyboard. I have a button in my custom section header view that triggers a segue that is set up in the storyboard.

Start with Tieme's solution

As pedro.m points out, the problem with this is that tapping the section header causes the first cell in the section to be selected.

As Paul Von points out, this is fixed by returning the cell's contentView instead of the whole cell.

However, as Hons points out, a long press on said section header will crash the app.

The solution is to remove any gestureRecognizers from contentView.

-(UIView *)tableView:(UITableView *)tableView viewForHeaderInSection:(NSInteger)section {
     static NSString *CellIdentifier = @"SectionHeader";
     UITableViewCell *sectionHeaderView = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];

     while (sectionHeaderView.contentView.gestureRecognizers.count) {
         [sectionHeaderView.contentView removeGestureRecognizer:[sectionHeaderView.contentView.gestureRecognizers objectAtIndex:0]];

     return sectionHeaderView.contentView; }

If you aren't using gestures in your section header views, this little hack seems to get it done.

Execute command on all files in a directory

Based on @Jim Lewis's approach:

Here is a quick solution using find and also sorting files by their modification date:

$ find  directory/ -maxdepth 1 -type f -print0 | \
  xargs -r0 stat -c "%y %n" | \
  sort | cut -d' ' -f4- | \
  xargs -d "\n" -I{} cmd -op1 {} 

For sorting see:

Calculate difference between two dates (number of days)?

DateTime xmas = new DateTime(2009, 12, 25);
double daysUntilChristmas = xmas.Subtract(DateTime.Today).TotalDays;

How can I format a String number to have commas and round?

You can do the entire conversion in one line, using the following code:

String number = "1000500000.574";
String convertedString = new DecimalFormat("#,###.##").format(Double.parseDouble(number));

The last two # signs in the DecimalFormat constructor can also be 0s. Either way works.

Conditionally ignoring tests in JUnit 4

A quick note: Assume.assumeTrue(condition) ignores rest of the steps but passes the test. To fail the test, use inside the conditional statement. Works same like Assume.assumeTrue() but fails the test.

How do I add a new class to an element dynamically?

CSS really doesn't have the ability to modify an object in the same manner as JavaScript, so in short - no.

How to force Sequential Javascript Execution?

Another way to look at this is to daisy chain from one function to another. Have an array of functions that is global to all your called functions, say:

arrf: [ f_final
       ,f_again ],

Then setup an array of integers to the particular 'f''s you want to run, e.g

var runorder = [1,3,2,0];

Then call an initial function with 'runorder' as a parameter, e.g. f_start(runorder);

Then at the end of each function, just pop the index to the next 'f' to execute off the runorder array and execute it, still passing 'runorder' as a parameter but with the array reduced by one.

var nextf = runorder.shift();

Obviously this terminates in a function, say at index 0, that does not chain onto another function. This is completely deterministic, avoiding 'timers'.

Which to use <div class="name"> or <div id="name">?

ID provides a unique indentifier for the element, in case you want to manipulate it in JavaScript. The class attribute can be used to treat a group of HTML elements the same, particularly in regards to fonts, colors and other style properties...

Using Rsync include and exclude options to include directory and file by pattern

Add -m to the recommended answer above to prune empty directories.

How to programmatically disable page scrolling with jQuery

I just provide a little tuning to the solution by tfe. In particular, I added some additional control to ensure that there is no shifting of the page content (aka page shift) when the scrollbar is set to hidden.

Two Javascript functions lockScroll() and unlockScroll() can be defined, respectively, to lock and unlock the page scroll.

function lockScroll(){
    $html = $('html'); 
    $body = $('body'); 
    var initWidth = $body.outerWidth();
    var initHeight = $body.outerHeight();

    var scrollPosition = [
        self.pageXOffset || document.documentElement.scrollLeft || document.body.scrollLeft,
        self.pageYOffset || document.documentElement.scrollTop  || document.body.scrollTop
    $'scroll-position', scrollPosition);
    $'previous-overflow', $html.css('overflow'));
    $html.css('overflow', 'hidden');
    window.scrollTo(scrollPosition[0], scrollPosition[1]);   

    var marginR = $body.outerWidth()-initWidth;
    var marginB = $body.outerHeight()-initHeight; 
    $body.css({'margin-right': marginR,'margin-bottom': marginB});

function unlockScroll(){
    $html = $('html');
    $body = $('body');
    $html.css('overflow', $'previous-overflow'));
    var scrollPosition = $'scroll-position');
    window.scrollTo(scrollPosition[0], scrollPosition[1]);    

    $body.css({'margin-right': 0, 'margin-bottom': 0});

where I assumed that the <body> has no initial margin.

Notice that, while the above solution works in most of the practical cases, it is not definitive since it needs some further customization for pages that include, for instance, an header with position:fixed. Let's go into this special case with an example. Suppose to have

<div id="header">My fixedheader</div>


#header{position:fixed; padding:0; margin:0; width:100%}

Then, one should add the following in functions lockScroll() and unlockScroll():

function lockScroll(){

    $('#header').css('margin-right', marginR);

function unlockScroll(){

    $('#header').css('margin-right', 0);

Finally, take care of some possible initial value for the margins or paddings.

Cannot open output file, permission denied

FOR LINUX OS... go to file where u r created file.then usually ......project_name/bin/Debug/project_name.executable here for this executable file you wont be having execute permission then the execute permission.Either by right click if you are unable to change permission then use use open terminal(command promt) to change permission. first go to that executable file using 'cd' command then use "chmod u+x" then permission is going to change.then go to c::b open and execute you will get output.

only thing for all file u need to do it.