Programs & Examples On #Fasta

FASTA is a software package for sequence alignment of proteins and nucleic acids. FASTA is also the name of the file format used by these programs to represent sequences of peptides or nucleotides. The format is a de facto standard in bioinformatics.

Shell script not running, command not found

Make sure you are not using "PATH" as a variable, which will override the existing PATH for environment variables.

Getting Python error "from: can't read /var/mail/Bio"

Put this at the top of your .py file (for python 2.x)

#!/usr/bin/env python 

or for python 3.x

#!/usr/bin/env python3

This should look up the python environment, without it, it will execute the code as if it were not python code, but straight to the CLI. If you need to specify a manual location of python environment put


Changing file extension in Python

Using pathlib and preserving full path:

from pathlib import Path
p = Path('/User/my/path')
new_p = Path(p.parent.as_posix() + '/' + p.stem + '.aln')

How to check java bit version on Linux?

Why don't you examine System.getProperty("os.arch") value in your code?

React Native absolute positioning horizontal centre

You can center absolute items by providing the left property with the width of the device divided by two and subtracting out half of the element you'd like to center's width.

For example, your style might look something like this.

bottom: {
    position: 'absolute',
    left: (Dimensions.get('window').width / 2) - 25,
    top: height*0.93,

How to generate a random string of 20 characters

public String randomString(String chars, int length) {
  Random rand = new Random();
  StringBuilder buf = new StringBuilder();
  for (int i=0; i<length; i++) {
  return buf.toString();

How do I detect if a user is already logged in Firebase?

If you are allowing anonymous users as well as those logged in with email you can use firebase.auth().currentUser.isAnonymous, which will return either true or false.

Open youtube video in Fancybox jquery

Thanx, Alexander!

And to set the fancy-close button above the youtube's flash-content add 'wmode' to 'swf' parameters:

'swf': {'allowfullscreen':'true', 'wmode':'transparent'}

How can I display my windows user name in excel spread sheet using macros?

Range("A1").value = Environ("Username")

This is better than Application.Username, which doesn't always supply the Windows username. Thanks to Kyle for pointing this out.

  • Application Username is the name of the User set in Excel > Tools > Options
  • Environ("Username") is the name you registered for Windows; see Control Panel >System

Codeigniter $this->input->post() empty while $_POST is working correctly

The problem is that $this->input->post() does not support getting all POST data, only specific data, for example $this->input->post('my_post_var'). This is why var_dump($this->input->post()); is empty.

A few solutions, stick to $_POST for retrieving all POST data, or assign variables from each POST item that you need, for example:

// variables will be false if not post data exists
$var_1 = $this->input->post('my_post_var_1');
$var_2 = $this->input->post('my_post_var_2');
$var_3 = $this->input->post('my_post_var_3');

However, since the above code is not very DRY, I like to do the following:

    // get all post data in one nice array
    foreach ($_POST as $key => $value) 
        $insert[$key] = $value;
    // user hasen't submitted anything yet!

How to execute logic on Optional if not present?

First of all, your dao.find() should either return an Optional<Obj> or you will have to create one.


Optional<Obj> = dao.find();

or you can do it yourself like:

Optional<Obj> = Optional.ofNullable(dao.find());

this one will return Optional<Obj> if present or Optional.empty() if not present.

So now let's get to the solution,

public Obj getObjectFromDB() {
   return Optional.ofNullable(dao.find()).flatMap(ob -> {
            return Optional.of(ob);    
        }).orElseGet(() -> {
            logger.fatal("Object not available");
            return null;

This is the one liner you're looking for :)

Cannot open output file, permission denied

Make sure to run 7zip in 'Administrator mode' for extracting to Program Files.

Also, temporarily turning off virus protection worked for some people in the past.

How to enable native resolution for apps on iPhone 6 and 6 Plus?

Do the following (see in photo)

  1. Goto asset catalog
  2. right-click and choose "Add New Launch Image"

    • iPhone 6 -> 750 x 1334
    • iPhone 6 Plus -> 1242 x 2208 and 2208 x 1242

enter image description here

How to change a <select> value from JavaScript

If you would like it to go back to first option try this:

   document.getElementById("select").selectedIndex = 0;

Calendar date to yyyy-MM-dd format in java

A Java Date is a container for the number of milliseconds since January 1, 1970, 00:00:00 GMT.

When you use something like System.out.println(date), Java uses Date.toString() to print the contents.

The only way to change it is to override Date and provide your own implementation of Date.toString(). Now before you fire up your IDE and try this, I wouldn't; it will only complicate matters. You are better off formatting the date to the format you want to use (or display).

Java 8+

LocalDateTime ldt =;
DateTimeFormatter formmat1 = DateTimeFormatter.ofPattern("yyyy-MM-dd", Locale.ENGLISH);
// Output "2018-05-12T17:21:53.658"

String formatter = formmat1.format(ldt);
// 2018-05-12

Prior to Java 8

You should be making use of the ThreeTen Backport

The following is maintained for historical purposes (as the original answer)

What you can do, is format the date.

Calendar cal = Calendar.getInstance();
cal.add(Calendar.DATE, 1);
SimpleDateFormat format1 = new SimpleDateFormat("yyyy-MM-dd");
// Output "Wed Sep 26 14:23:28 EST 2012"

String formatted = format1.format(cal.getTime());
// Output "2012-09-26"

// Output "Wed Sep 26 00:00:00 EST 2012"

These are actually the same date, represented differently.

Base table or view not found: 1146 Table Laravel 5

Just run the command:

php artisan migrate:refresh --seed

how to get text from textview

split with the + sign like this way

String a = tv.getText().toString();
String aa[];
    aa = a.split("+");

now convert the array

Integer.parseInt(aa[0]); // and so on

HTML Form: Select-Option vs Datalist-Option

I noticed that there is no selected feature in datalist. It only gives you choice but can't have a default option. You can't show the selected option on the next page either.

Breaking out of nested loops

Use itertools.product!

from itertools import product
for x, y in product(range(10), range(10)):
    #do whatever you want

Here's a link to itertools.product in the python documentation:

You can also loop over an array comprehension with 2 fors in it, and break whenever you want to.

>>> [(x, y) for y in ['y1', 'y2'] for x in ['x1', 'x2']]
    ('x1', 'y1'), ('x2', 'y1'),
    ('x1', 'y2'), ('x2', 'y2')

jQuery 'each' loop with JSON array

Try (untested):

$.getJSON("data.php", function(data){
    $.each(data.justIn, function() {
        $.each(this, function(k, v) {
            alert(k + ' ' + v);
    $.each(data.recent, function() {
        $.each(this, function(k, v) {
            alert(k + ' ' + v);
    $.each(data.old, function() {
        $.each(this, function(k, v) {
            alert(k + ' ' + v);

I figured, three separate loops since you'll probably want to treat each dataset differently (justIn, recent, old). If not, you can do:

$.getJSON("data.php", function(data){
    $.each(data, function(k, v) {
        alert(k + ' ' + v);
        $.each(v, function(k1, v1) {
            alert(k1 + ' ' + v1);

How to get the width of a react element

This is basically Marco Antônio's answer for a React custom hook, but modified to set the dimensions initially and not only after a resize.

export const useContainerDimensions = myRef => {
  const getDimensions = () => ({
    width: myRef.current.offsetWidth,
    height: myRef.current.offsetHeight

  const [dimensions, setDimensions] = useState({ width: 0, height: 0 })

  useEffect(() => {
    const handleResize = () => {

    if (myRef.current) {

    window.addEventListener("resize", handleResize)

    return () => {
      window.removeEventListener("resize", handleResize)
  }, [myRef])

  return dimensions;

Used in the same way:

const MyComponent = () => {
  const componentRef = useRef()
  const { width, height } = useContainerDimensions(componentRef)

  return (
    <div ref={componentRef}>
      <p>width: {width}px</p>
      <p>height: {height}px</p>

StringStream in C#

I see a lot of good answers here, but none that directly address the lack of a StringStream class in C#. So I have written one of my own...

public class StringStream : Stream
    private readonly MemoryStream _memory;
    public StringStream(string text)
        _memory = new MemoryStream(Encoding.UTF8.GetBytes(text));
    public StringStream()
        _memory = new MemoryStream();
    public StringStream(int capacity)
        _memory = new MemoryStream(capacity);
    public override void Flush()
    public override int Read(byte[] buffer, int offset, int count)
        return  _memory.Read(buffer, offset, count);
    public override long Seek(long offset, SeekOrigin origin)
        return _memory.Seek(offset, origin);
    public override void SetLength(long value)
    public override void Write(byte[] buffer, int offset, int count)
        _memory.Write(buffer, offset, count);
    public override bool CanRead => _memory.CanRead;
    public override bool CanSeek => _memory.CanSeek;
    public override bool CanWrite => _memory.CanWrite;
    public override long Length =>  _memory.Length;
    public override long Position
        get => _memory.Position;
        set => _memory.Position = value;
    public override string ToString()
        return System.Text.Encoding.UTF8.GetString(_memory.GetBuffer(), 0, (int) _memory.Length);
    public override int ReadByte()
        return _memory.ReadByte();
    public override void WriteByte(byte value)

An example of its use...

        string s0 =
            "Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor\r\n" +
            "incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud\r\n" +
            "exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor\r\n" +
            "in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint\r\n" +
            "occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.\r\n";
        StringStream ss0 = new StringStream(s0);
        StringStream ss1 = new StringStream();
        int line = 1;
        Console.WriteLine("Contents of input stream: ");
        using (StreamReader reader = new StreamReader(ss0))
            using (StreamWriter writer = new StreamWriter(ss1))
                while (!reader.EndOfStream)
                    string s = reader.ReadLine();
                    Console.WriteLine("Line " + line++ + ": " + s);

        Console.WriteLine("Contents of output stream: ");

return results from a function (javascript, nodejs)

You are trying to execute an asynchronous function in a synchronous way, which is unfortunately not possible in Javascript.

As you guessed correctly, the roomId=results.... is executed when the loading from the DB completes, which is done asynchronously, so AFTER the resto of your code is completed.

Look at this article, it talks about .insert and not .find, but the idea is the same :

How do you initialise a dynamic array in C++?

The array form of new-expression accepts only one form of initializer: an empty (). This, BTW, has the same effect as the empty {} in your non-dynamic initialization.

The above applies to pre-C++11 language. Starting from C++11 one can use uniform initialization syntax with array new-expressions

char* c = new char[length]{};
char* d = new char[length]{ 'a', 'b', 'c' };

How to fire an event on class change using jQuery?

There is no event raised when a class changes. The alternative is to manually raise an event when you programatically change the class:

$someElement.on('event', function() {

// in another js file, far, far away
$('#myDiv').on('classChange', function() {
     // do stuff


This question seems to be gathering some visitors, so here is an update with an approach which can be used without having to modify existing code using the new MutationObserver:

var $div = $("#foo");_x000D_
var observer = new MutationObserver(function(mutations) {_x000D_
  mutations.forEach(function(mutation) {_x000D_
    if (mutation.attributeName === "class") {_x000D_
      var attributeValue = $(;_x000D_
      console.log("Class attribute changed to:", attributeValue);_x000D_
observer.observe($div[0], {_x000D_
  attributes: true_x000D_
.red { color: #C00; }
<script src=""></script>_x000D_
<div id="foo" class="bar"></div>

Be aware that the MutationObserver is only available for newer browsers, specifically Chrome 26, FF 14, IE 11, Opera 15 and Safari 6. See MDN for more details. If you need to support legacy browsers then you will need to use the method I outlined in my first example.

How do I tell whether my IE is 64-bit? (For that matter, Java too?)

Select Help->About

for 64 bit.. it would say version as 64 bit Edition.

I see this in IE 9.. may be true with lesser versions too..


I wanted to verify myself that 'SET NOCOUNT ON' does not save a network packet nor a roundtrip

I used a test SQLServer 2017 on another host (I used a VM) create table ttable1 (n int); insert into ttable1 values (1),(2),(3),(4),(5),(6),(7) go create procedure procNoCount as begin set nocount on update ttable1 set n=10-n end create procedure procNormal as begin update ttable1 set n=10-n end Then I traced packets on port 1433 with the tool 'Wireshark': 'capture filter' button -> 'port 1433'

exec procNoCount

this is the response packet: 0000 00 50 56 c0 00 08 00 0c 29 31 3f 75 08 00 45 00 0010 00 42 d0 ce 40 00 40 06 84 0d c0 a8 32 88 c0 a8 0020 32 01 05 99 fe a5 91 49 e5 9c be fb 85 01 50 18 0030 02 b4 e6 0e 00 00 04 01 00 1a 00 35 01 00 79 00 0040 00 00 00 fe 00 00 e0 00 00 00 00 00 00 00 00 00

exec procNormal

this is the response packet: 0000 00 50 56 c0 00 08 00 0c 29 31 3f 75 08 00 45 00 0010 00 4f d0 ea 40 00 40 06 83 e4 c0 a8 32 88 c0 a8 0020 32 01 05 99 fe a5 91 49 e8 b1 be fb 8a 35 50 18 0030 03 02 e6 1b 00 00 04 01 00 27 00 35 01 00 ff 11 0040 00 c5 00 07 00 00 00 00 00 00 00 79 00 00 00 00 0050 fe 00 00 e0 00 00 00 00 00 00 00 00 00

On line 40 I can see '07' which is the number of 'row(s) affected'. It is included in the response packet. No extra packet.

It has however 13 extra bytes which could be saved, but probably not more worth it than reducing column names (e.g. 'ManagingDepartment' to 'MD')

So I see no reason to use it for performance

BUT As others mentioned it can break ADO.NET and I also stumbled on an issue using python: MSSQL2008 - Pyodbc - Previous SQL was not a query

So probably a good habit still...

How do I download a tarball from GitHub using cURL?

The modernized way of doing this is:

curl -sL | tar xz

Replace user-or-org, repo, and sha1-or-ref accordingly.

If you want a zip file instead of a tarball, specify .zip instead of .tar.gz suffix.

You can also retrieve the archive of a private repo, by specifying -u token:x-oauth-basic option to curl. Replace token with a personal access token.

What's the HTML to have a horizontal space between two objects?

I think what you mean is putting 2 paragraphs (for example) in 2 columns instead of one below the other? In that case, I think float is your solution.

<div style="float: left"> <!-- would cause this to hang on the left -->
<div style="float: right"> <!-- would cause this to hang on the right-->

Here's an example:

How to make a SIMPLE C++ Makefile

I suggest (note that the indent is a TAB):

tool: tool.o file1.o file2.o
    $(CXX) $(LDFLAGS) $^ $(LDLIBS) -o $@


tool: tool.o file1.o file2.o

The latter suggestion is slightly better since it reuses GNU Make implicit rules. However, in order to work, a source file must have the same name as the final executable (i.e.: tool.c and tool).

Notice, it is not necessary to declare sources. Intermediate object files are generated using implicit rule. Consequently, this Makefile work for C and C++ (and also for Fortran, etc...).

Also notice, by default, Makefile use $(CC) as the linker. $(CC) does not work for linking C++ object files. We modify LINK.o only because of that. If you want to compile C code, you don't have to force the LINK.o value.

Sure, you can also add your compilation flags with variable CFLAGS and add your libraries in LDLIBS. For example:

CFLAGS = -Wall
LDLIBS = -lm

One side note: if you have to use external libraries, I suggest to use pkg-config in order to correctly set CFLAGS and LDLIBS:

CFLAGS += $(shell pkg-config --cflags libssl)
LDLIBS += $(shell pkg-config --libs libssl)

The attentive reader will notice that this Makefile does not rebuild properly if one header is changed. Add these lines to fix the problem:

override CPPFLAGS += -MMD
include $(wildcard *.d)

-MMD allows to build .d files that contains Makefile fragments about headers dependencies. The second line just uses them.

For sure, a well written Makefile should also include clean and distclean rules:

    $(RM) *.o *.d

distclean: clean
    $(RM) tool

Notice, $(RM) is the equivalent of rm -f, but it is a good practice to not call rm directly.

The all rule is also appreciated. In order to work, it should be the first rule of your file:

all: tool

You may also add an install rule:

PREFIX = /usr/local
    install -m 755 tool $(DESTDIR)$(PREFIX)/bin

DESTDIR is empty by default. The user can set it to install your program at an alternative system (mandatory for cross-compilation process). Package maintainers for multiple distribution may also change PREFIX in order to install your package in /usr.

One final word: Do not place source files in sub-directories. If you really want to do that, keep this Makefile in the root directory and use full paths to identify your files (i.e. subdir/file.o).

So to summarise, your full Makefile should look like:

PREFIX = /usr/local
override CPPFLAGS += -MMD
include $(wildcard *.d)

all: tool
tool: tool.o file1.o file2.o
    $(RM) *.o *.d
distclean: clean
    $(RM) tool
    install -m 755 tool $(DESTDIR)$(PREFIX)/bin

Html- how to disable <a href>?

You can use CSS to accomplish this:

.disabled {
  pointer-events: none;
  cursor: default;
<a href="somelink.html" class="disabled">Some link</a>

Or you can use JavaScript to prevent the default action like this:


Project vs Repository in GitHub

The conceptual difference in my understanding it that a project can contain many repo's and that are independent of each other, while simultaneously a repo may contain many projects. Repo's being just a storage place for code while a project being a collection of tasks for a certain feature.

Does that make sense? A large repo can have many projects being worked on by different people at the same time (lots of difference features being added to a monolith), a large project may have many small repos that are separate but part of the same project that interact with each other - microservices? Its a personal take on what you want to do. I think that repo (storage) vs project (tasks) is the main difference - if i am wrong please let me know / explain! Thanks.

Using quotation marks inside quotation marks

Use the literal escape character \

print("Here is, \"a quote\"")

The character basically means ignore the semantic context of my next charcter, and deal with it in its literal sense.

Preventing twitter bootstrap carousel from auto sliding on page load

I think maybe you should go to check the official instruction about carousel, for me, i have not found answer above, because of multiple versions of bootstrap, I'm using b4-alpha and i want the autoplay effect stop.


this script does not make any effect while mouse leave that page, exactly carousel area. go to official definition and find those :

enter image description here

So you will find why.if carousel page onmouseover event triggered, page will pause, while mouse out of that page, it'll resume again.

So, if you want a page stop forever and rotate manually, you can just set data-interval='false'.

Convert string to decimal number with 2 decimal places in Java

Use BigDecimal:

new BigDecimal(theInputString);

It retains all decimal digits. And you are sure of the exact representation since it uses decimal base, not binary base, to store the precision/scale/etc.

And it is not subject to precision loss like float or double are, unless you explicitly ask it to.

How do you import classes in JSP?

In the page tag:

<%@ page import="java.util.List" %>

Why does checking a variable against multiple values with `OR` only check the first value?

("Jesse" or "jesse")

The above expression tests whether or not "Jesse" evaluates to True. If it does, then the expression will return it; otherwise, it will return "jesse". The expression is equivalent to writing:

"Jesse" if "Jesse" else "jesse"

Because "Jesse" is a non-empty string though, it will always evaluate to True and thus be returned:

>>> bool("Jesse")  # Non-empty strings evaluate to True in Python
>>> bool("")  # Empty strings evaluate to False
>>> ("Jesse" or "jesse")
>>> ("" or "jesse")

This means that the expression:

name == ("Jesse" or "jesse")

is basically equivalent to writing this:

name == "Jesse"

In order to fix your problem, you can use the in operator:

# Test whether the value of name can be found in the tuple ("Jesse", "jesse")
if name in ("Jesse", "jesse"):

Or, you can lowercase the value of name with str.lower and then compare it to "jesse" directly:

# This will also handle inputs such as "JeSSe", "jESSE", "JESSE", etc.
if name.lower() == "jesse":

How can you get the Manifest Version number from the App's (Layout) XML variables?

There is not a way to directly get the version out, but there are two work-arounds that could be done.

  1. The version could be stored in a resource string, and placed into the manifest by:

    <manifest xmlns:android=""
         android:versionName="@string/version" android:versionCode="20">
  2. One could create a custom view, and place it into the XML. The view would use this to assign the name:

    context.getPackageManager().getPackageInfo(context.getPackageName(), 0).versionName;

Either of these solutions would allow for placing the version name in XML. Unfortunately there isn't a nice simple solution, like android.R.string.version or something like that.

What is the function __construct used for?

I believe that function __construct () {...} is a piece of code that can be reused again and again in substitution for TheActualFunctionName () {...}. If you change the CLASS Name you do not have to change within the code because the generic __construct refers always to the actual class name...whatever it is. You code less...or?

Youtube - downloading a playlist - youtube-dl

Download YouTube playlist videos in separate directory indexed by video order in a playlist

$ youtube-dl -o '%(playlist)s/%(playlist_index)s - %(title)s.%(ext)s'

Download all playlists of YouTube channel/user keeping each playlist in separate directory:

$ youtube-dl -o '%(uploader)s/%(playlist)s/%(playlist_index)s - %(title)s.%(ext)s'

Video Selection:

youtube-dl is a command-line program to download videos from and a few more sites. It requires the Python interpreter, version 2.6, 2.7, or 3.2+, and it is not platform specific. It should work on your Unix box, on Windows or on macOS. It is released to the public domain, which means you can modify it, redistribute it or use it however you like.

$ youtube-dl [OPTIONS] URL [URL...]
--playlist-start NUMBER          Playlist video to start at (default is 1)

--playlist-end NUMBER            Playlist video to end at (default is last)

--playlist-items ITEM_SPEC       Playlist video items to download. Specify
                                 indices of the videos in the playlist
                                 separated by commas like: "--playlist-items
                                 1,2,5,8" if you want to download videos
                                 indexed 1, 2, 5, 8 in the playlist. You can
                                 specify range: "--playlist-items
                                 1-3,7,10-13", it will download the videos
                                 at index 1, 2, 3, 7, 10, 11, 12 and 13.

ImportError: No Module Named bs4 (BeautifulSoup)

You might want to try install bs4 with

pip install --ignore-installed BeautifulSoup4

if the methods above didn't work for you.

Getting a timestamp for today at midnight?

$timestamp = strtotime('today midnight');

is the same as

$timestamp = strtotime('today');

and it's a little less work on your server.

User Control - Custom Properties

Just add public properties to the user control.

You can add [Category("MyCategory")] and [Description("A property that controls the wossname")] attributes to make it nicer, but as long as it's a public property it should show up in the property panel.

How can I remove 3 characters at the end of a string in php?

<?php echo substr($string, 0, strlen($string) - 3); ?>

Align Bootstrap Navigation to Center

.navbar-nav {
   float: left;
   margin: 0;
   margin-left: 40%;

.navbar-nav.navbar-right:last-child {
   margin-right: -15px;
   margin-left: 0;

Updated Fiddle

Since You Have used the float property we don't have many options except to adjust it manually.

Set mouse focus and move cursor to end of input using jQuery

set the value first. then set the focus. when it focuses, it will use the value that exists at the time of focus, so your value must be set first.

this logic works for me with an application that populates an <input> with the value of a clicked <button>. val() is set first. then focus()

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

What is the difference between C and embedded C?

Embedded C is generally an extension of the C language, they are more or less similar. However, some differences do exist, such as:

  • C is generally used for desktop computers, while embedded C is for microcontroller based applications.

  • C can use the resources of a desktop PC like memory, OS, etc. While, embedded C has to use with the limited resources, such as RAM, ROM, I/Os on an embedded processor.

  • Embedded C includes extra features over C, such as fixed point types, multiple memory areas, and I/O register mapping.

  • Compilers for C (ANSI C) typically generate OS dependant executables. Embedded C requires compilers to create files to be downloaded to the microcontrollers/microprocessors where it needs to run.

Refer difference between C and embedded C

Finding all cycles in a directed graph

First of all - you do not really want to try find literally all cycles because if there is 1 then there is an infinite number of those. For example A-B-A, A-B-A-B-A etc. Or it may be possible to join together 2 cycles into an 8-like cycle etc., etc... The meaningful approach is to look for all so called simple cycles - those that do not cross themselves except in the start/end point. Then if you wish you can generate combinations of simple cycles.

One of the baseline algorithms for finding all simple cycles in a directed graph is this: Do a depth-first traversal of all simple paths (those that do not cross themselves) in the graph. Every time when the current node has a successor on the stack a simple cycle is discovered. It consists of the elements on the stack starting with the identified successor and ending with the top of the stack. Depth first traversal of all simple paths is similar to depth first search but you do not mark/record visited nodes other than those currently on the stack as stop points.

The brute force algorithm above is terribly inefficient and in addition to that generates multiple copies of the cycles. It is however the starting point of multiple practical algorithms which apply various enhancements in order to improve performance and avoid cycle duplication. I was surprised to find out some time ago that these algorithms are not readily available in textbooks and on the web. So I did some research and implemented 4 such algorithms and 1 algorithm for cycles in undirected graphs in an open source Java library here : .

BTW, since I mentioned undirected graphs : The algorithm for those is different. Build a spanning tree and then every edge which is not part of the tree forms a simple cycle together with some edges in the tree. The cycles found this way form a so called cycle base. All simple cycles can then be found by combining 2 or more distinct base cycles. For more details see e.g. this : .

add id to dynamically created <div>

You can add the id="MyID123" at the start of the cartHTML text appends.

The first line would therefore be:

var cartHTML = '<div id="MyID123" class="soft_add_wrapper" onmouseover="setTimer();">';


If you want the ID to be in a variable, then something like this:

    var MyIDvariable = "MyID123";
    var cartHTML = '<div id="'+MyIDvariable+'" class="soft_add_wrapper" onmouseover="setTimer();">';
/* ... the rest of your code ... */

Advantages of using display:inline-block vs float:left in CSS

There is one characteristic about inline-block which may not be straight-forward though. That is that the default value for vertical-align in CSS is baseline. This may cause some unexpected alignment behavior. Look at this article.

Instead, when you do a float:left, the divs are independent of each other and you can align them using margin easily.

How is Pythons glob.glob ordered?

Please try this code:

sorted(glob.glob( os.path.join(path, '*.png') ),key=lambda x:float(re.findall("([0-9]+?)\.png",x)[0]))

How to smooth a curve in the right way?

For a project of mine, I needed to create intervals for time-series modeling, and to make the procedure more efficient I created tsmoothie: A python library for time-series smoothing and outlier detection in a vectorized way.

It provides different smoothing algorithms together with the possibility to computes intervals.

Here I use a ConvolutionSmoother but you can also test it others.

import numpy as np
import matplotlib.pyplot as plt
from tsmoothie.smoother import *

x = np.linspace(0,2*np.pi,100)
y = np.sin(x) + np.random.random(100) * 0.2

# operate smoothing
smoother = ConvolutionSmoother(window_len=5, window_type='ones')

# generate intervals
low, up = smoother.get_intervals('sigma_interval', n_sigma=2)

# plot the smoothed timeseries with intervals
plt.plot(smoother.smooth_data[0], linewidth=3, color='blue')
plt.plot([0], '.k')
plt.fill_between(range(len([0])), low[0], up[0], alpha=0.3)

enter image description here

I point out also that tsmoothie can carry out the smoothing of multiple timeseries in a vectorized way

Integer ASCII value to character in BASH using printf

If you want to save the ASCII value of the character: (I did this in BASH and it worked)


testing=$( printf "%d" "'${char}" )

echo $testing}

output: 65

how to modify the size of a column

This was done using Toad for Oracle


For example,


File loading by getClass().getResource()

getClass().getResource() uses the class loader to load the resource. This means that the resource must be in the classpath to be loaded.

When doing it with Eclipse, everything you put in the source folder is "compiled" by Eclipse:

  • .java files are compiled into .class files that go the the bin directory (by default)
  • other files are copied to the bin directory (respecting the package/folder hirearchy)

When launching the program with Eclipse, the bin directory is thus in the classpath, and since it contains the file, this file can be loaded by the class loader, using getResource() or getResourceAsStream().

If it doesn't work from the command line, it's thus because the file is not in the classpath.

Note that you should NOT do

FileInputStream inputStream = new FileInputStream(new File(getClass().getResource(url).toURI()));

to load a resource. Because that can work only if the file is loaded from the file system. If you package your app into a jar file, or if you load the classes over a network, it won't work. To get an InputStream, just use


And finally, as the documentation indicates,


will load a file located in the same package as the class Foo.


will load a file located in the package

Youtube API Limitations

A little bit late, but you can request a higher quote here:

Openssl is not recognized as an internal or external command

I used this code:

This is worked for me successfully.

"C:\Program Files\Java\jdk1.6.0_26\bin\keytool.exe" -exportcert -alias sociallisting -
keystore "D:\keystore\SocialListing" | "C:\cygwin\bin\openssl.exe" sha1 -binary | 
"C:\cygwin\bin\openssl.exe" base64

How do I print an IFrame from javascript in Safari/Chrome

You can use


Work at Chrome!

numbers not allowed (0-9) - Regex Expression in javascript



That pattern matches any number of characters that is not 0 through 9.

I recommend checking out It will let you easily test out a regex.

convert array into DataFrame in Python

You can add parameter columns or use dict with key which is converted to column name:

e = np.random.normal(size=10)  
dataframe=pd.DataFrame(e, columns=['a']) 
print (dataframe)
0 -1.085631
1  0.997345
2  0.282978
3 -1.506295
4 -0.578600
5  1.651437
6 -2.426679
7 -0.428913
8  1.265936
9 -0.866740

print (e_dataframe)
0 -1.085631
1  0.997345
2  0.282978
3 -1.506295
4 -0.578600
5  1.651437
6 -2.426679
7 -0.428913
8  1.265936
9 -0.866740

Change bar plot colour in geom_bar with ggplot2 in r

If you want all the bars to get the same color (fill), you can easily add it inside geom_bar.

ggplot(data=df, aes(x=c1+c2/2, y=c3)) + 
geom_bar(stat="identity", width=c2, fill = "#FF6666")

enter image description here

Add fill = the_name_of_your_var inside aes to change the colors depending of the variable :

c4 = c("A", "B", "C")
df = cbind(df, c4)
ggplot(data=df, aes(x=c1+c2/2, y=c3, fill = c4)) + 
geom_bar(stat="identity", width=c2)

enter image description here

Use scale_fill_manual() if you want to manually the change of colors.

ggplot(data=df, aes(x=c1+c2/2, y=c3, fill = c4)) + 
geom_bar(stat="identity", width=c2) + 
scale_fill_manual("legend", values = c("A" = "black", "B" = "orange", "C" = "blue"))

enter image description here

How to use Fiddler to monitor WCF service

Fiddler listens to outbound requests rather than inbound requests so you're not going to be able to monitor all the requests coming in to your service by using Fiddler.

The best you're going to get with Fiddler is the ability to see all of the requests as they are generated by your Console App (assuming that the app generates web requests rather than using some other pipeline).

If you want a tool that is more powerful (but more difficult to use) that will allow you to monitor ALL incoming requests, you should check out WireShark.


I stand corrected. Thanks to Eric Law for posting the directions to configuring Fiddler to be a reverse proxy!

Using CSS :before and :after pseudo-elements with inline CSS?

As mentioned before, you can't use inline elements for styling pseudo classes. Before and after pseudo classes are states of elements, not actual elements. You could only possibly use JavaScript for this.

Semi-transparent color layer over background-image?

I simply used background-image css property on the target background div.
Note background-image only accepts gradient color functions.
So I used linear-gradient adding the same desired overlay color twice (use last rgba value to control color opacity).

Also, found these two useful resources to:

  1. Add text (or div with any other content) over the background image: Hero Image
  2. Blur background image only, without blurring the div on top: Blurred Background Image


<div class="header_div">

<div class="header_text">
  <h1>Header Text</h1>


.header_div {
  position: relative;
  text-align: cover;
  min-height: 90vh;
  margin-top: 5vh;
  background-position: center;
  background-repeat: no-repeat;
  background-size: cover;
  width: 100vw;
  background-image: linear-gradient(rgba(38, 32, 96, 0.2), rgba(38, 32, 96, 0.4)), url("images\\header img2.jpg");
  filter: blur(2px);

.header_text {
  position: absolute;
  top: 50%;
  right: 50%;
  transform: translate(50%, -50%);

Codeigniter - no input file specified

Godaddy hosting it seems fixed on .htaccess, myself it is working

RewriteRule ^(.*)$ index.php/$1 [L]


RewriteRule ^(.*)$ index.php?/$1 [QSA,L]

RuntimeError: module compiled against API version a but this version of numpy is 9

For those using anaconda Python:

conda update anaconda

iOS 7 App Icons, Launch images And Naming Convention While Keeping iOS 6 Icons

Okay adding to @null's awesome post about using the Asset Catalog.

You may need to do the following to get the App's Icon linked and working for Ad-Hoc distributions / production to be seen in Organiser, Test flight and possibly unknown AppStore locations.

After creating the Asset Catalog, take note of the name of the Launch Images and App Icon names listed in the .xassets in Xcode.

By Default this should be

  • AppIcon
  • LaunchImage

[To see this click on your .xassets folder/icon in Xcode.] (this can be changed, so just take note of this variable for later)

What is created now each build is the following data structures in your .app:

For App Icons:


  • AppIcon57x57.png (iPhone non retina) [Notice the Icon name prefix]
  • [email protected] (iPhone retina)

And the same format for each of the other icon resolutions.


  • AppIcon72x72~ipad.png (iPad non retina)
  • AppIcon72x72@2x~ipad.png (iPad retina)

(For iPad it is slightly different postfix)

Main Problem

Now I noticed that in my Info.plist in Xcode 5.0.1 it automatically attempted and failed to create a key for "Icon files (iOS 5)" after completing the creation of the Asset Catalog.

If it did create a reference successfully / this may have been patched by Apple or just worked, then all you have to do is review the image names to validate the format listed above.

Final Solution:

Add the following key to you main .plist

I suggest you open your main .plist with a external text editor such as TextWrangler rather than in Xcode to copy and paste the following key in.

            <string>[email protected]</string>

Please Note I have only included my example resolutions, you will need to add them all.

If you want to add this Key in Xcode without an external editor, Use the following:

  • Icon files (iOS 5) - Dictionary
  • Primary Icon - Dictionary
  • Icon files - Array
  • Item 0 - String = AppIcon57x57.png And for each other item / app icon.

Now when you finally archive your project the final .xcarchive payload .plist will now include the above stated icon locations to build and use.

Do not add the following to any .plist: Just an example of what Xcode will now generate for your final payload

    <string>Applications/[email protected]</string>

No notification sound when sending notification from firebase in android

The onMessageReceived method is fired only when app is in foreground or the notification payload only contains the data type.

From the Firebase docs

For downstream messaging, FCM provides two types of payload: notification and data.

For notification type, FCM automatically displays the message to end-user devices on behalf of the client app. Notifications have a predefined set of user-visible keys.
For data type, client app is responsible for processing data messages. Data messages have only custom key-value pairs.

Use notifications when you want FCM to handle displaying a notification on your client app's behalf. Use data messages when you want your app to handle the display or process the messages on your Android client app, or if you want to send messages to iOS devices when there is a direct FCM connection.

Further down the docs

App behaviour when receiving messages that include both notification and data payloads depends on whether the app is in the background or the foreground—essentially, whether or not it is active at the time of receipt.
When in the background, apps receive the notification payload in the notification tray, and only handle the data payload when the user taps on the notification.
When in the foreground, your app receives a message object with both payloads available.

If you are using the firebase console to send notifications, the payload will always contain the notification type. You have to use the Firebase API to send the notification with only the data type in the notification payload. That way your app is always notified when a new notification is received and the app can handle the notification payload.

If you want to play notification sound when app is in background using the conventional method, you need to add the sound parameter to the notification payload.

Specifying java version in maven - differences between properties and compiler plugin

How to specify the JDK version?

Use any of three ways: (1) Spring Boot feature, or use Maven compiler plugin with either (2) source & target or (3) with release.

Spring Boot

  1. <java.version> is not referenced in the Maven documentation.
    It is a Spring Boot specificity.
    It allows to set the source and the target java version with the same version such as this one to specify java 1.8 for both :


Feel free to use it if you use Spring Boot.

maven-compiler-plugin with source & target

  1. Using maven-compiler-plugin or maven.compiler.source/ properties are equivalent.

That is indeed :


is equivalent to :


according to the Maven documentation of the compiler plugin since the <source> and the <target> elements in the compiler configuration use the properties maven.compiler.source and if they are defined.


The -source argument for the Java compiler.
Default value is: 1.6.
User property is: maven.compiler.source.


The -target argument for the Java compiler.
Default value is: 1.6.
User property is:

About the default values for source and target, note that since the 3.8.0 of the maven compiler, the default values have changed from 1.5 to 1.6.

maven-compiler-plugin with release instead of source & target

  1. The maven-compiler-plugin 3.6 and later versions provide a new way :

    org.apache.maven.plugins maven-compiler-plugin 3.8.0 9

You could also declare just :


But at this time it will not work as the maven-compiler-plugin default version you use doesn't rely on a recent enough version.

The Maven release argument conveys release : a new JVM standard option that we could pass from Java 9 :

Compiles against the public, supported and documented API for a specific VM version.

This way provides a standard way to specify the same version for the source, the target and the bootstrap JVM options.
Note that specifying the bootstrap is a good practice for cross compilations and it will not hurt if you don't make cross compilations either.

Which is the best way to specify the JDK version?

The first way (<java.version>) is allowed only if you use Spring Boot.

For Java 8 and below :

About the two other ways : valuing the maven.compiler.source/ properties or using the maven-compiler-plugin, you can use one or the other. It changes nothing in the facts since finally the two solutions rely on the same properties and the same mechanism : the maven core compiler plugin.

Well, if you don't need to specify other properties or behavior than Java versions in the compiler plugin, using this way makes more sense as this is more concise:


From Java 9 :

The release argument (third point) is a way to strongly consider if you want to use the same version for the source and the target.

What happens if the version differs between the JDK in JAVA_HOME and which one specified in the pom.xml?

It is not a problem if the JDK referenced by the JAVA_HOME is compatible with the version specified in the pom but to ensure a better cross-compilation compatibility think about adding the bootstrap JVM option with as value the path of the rt.jar of the target version.

An important thing to consider is that the source and the target version in the Maven configuration should not be superior to the JDK version referenced by the JAVA_HOME.
A older version of the JDK cannot compile with a more recent version since it doesn't know its specification.

To get information about the source, target and release supported versions according to the used JDK, please refer to java compilation : source, target and release supported versions.

How handle the case of JDK referenced by the JAVA_HOME is not compatible with the java target and/or source versions specified in the pom?

For example, if your JAVA_HOME refers to a JDK 1.7 and you specify a JDK 1.8 as source and target in the compiler configuration of your pom.xml, it will be a problem because as explained, the JDK 1.7 doesn't know how to compile with.
From its point of view, it is an unknown JDK version since it was released after it.
In this case, you should configure the Maven compiler plugin to specify the JDK in this way :


You could have more details in examples with maven compiler plugin.

It is not asked but cases where that may be more complicated is when you specify source but not target. It may use a different version in target according to the source version. Rules are particular : you can read about them in the Cross-Compilation Options part.

Why the compiler plugin is traced in the output at the execution of the Maven package goal even if you don't specify it in the pom.xml?

To compile your code and more generally to perform all tasks required for a maven goal, Maven needs tools. So, it uses core Maven plugins (you recognize a core Maven plugin by its groupId : org.apache.maven.plugins) to do the required tasks : compiler plugin for compiling classes, test plugin for executing tests, and so for... So, even if you don't declare these plugins, they are bound to the execution of the Maven lifecycle.
At the root dir of your Maven project, you can run the command : mvn help:effective-pom to get the final pom effectively used. You could see among other information, attached plugins by Maven (specified or not in your pom.xml), with the used version, their configuration and the executed goals for each phase of the lifecycle.

In the output of the mvn help:effective-pom command, you could see the declaration of these core plugins in the <build><plugins> element, for example :


You can have more information about it in the introduction of the Maven lifeycle in the Maven documentation.

Nevertheless, you can declare these plugins when you want to configure them with other values as default values (for example, you did it when you declared the maven-compiler plugin in your pom.xml to adjust the JDK version to use) or when you want to add some plugin executions not used by default in the Maven lifecycle.

jQuery get the rendered height of an element?

It should just be


with jQuery. This retrieves the height of the first item in the wrapped set as a number.

Trying to use


only works if you have set the property in the first place. Not very useful!

How to get a list of column names on Sqlite3 database?

I know it's too late but this will help other.

To find the column name of the table, you should execute select * from tbl_name and you will get the result in sqlite3_stmt *. and check the column iterate over the total fetched column. Please refer following code for the same.

// sqlite3_stmt *statement ;
int totalColumn = sqlite3_column_count(statement);
for (int iterator = 0; iterator<totalColumn; iterator++) {
   NSLog(@"%s", sqlite3_column_name(statement, iterator));

This will print all the column names of the result set.

What does "Could not find or load main class" mean?

Excluding the following files solved the problem.




Added the following code in build.gradle

jar {
    from {
        configurations.compile.collect { it.isDirectory() ? it : zipTree(it) }
        exclude "META-INF/*.SF"
        exclude "META-INF/*.DSA"
        exclude "META-INF/*.RSA"
    manifest {
                'Main-Class': 'mainclass'

postgresql sequence nextval in schema

SELECT last_value, increment_by from "other_schema".id_seq;

for adding a seq to a column where the schema is not public try this.


How to run shell script file using nodejs?

You can execute any shell command using the shelljs module

 const shell = require('shelljs')


Why fragments, and when to use fragments instead of activities?

This is important information that I found on fragments:

Historically each screen in an Android app was implemented as a separate Activity. This creates a challenge in passing information between screens because the Android Intent mechanism does not allow passing a reference type (i.e. object) directly between Activities. Instead the object must be serialized or a globally accessible reference made available.

By making each screen a separate Fragment, this data passing headache is completely avoided. Fragments always exist within the context of a given Activity and can always access that Activity. By storing the information of interest within the Activity, the Fragment for each screen can simply access the object reference through the Activity.


PHP remove all characters before specific string


$string="We have www/audio path where the audio files are stored";  //Considering the string like this

Either you can use

strstr($string, 'www/audio');



How to execute raw SQL in Flask-SQLAlchemy app

You can get the results of SELECT SQL queries using from_statement() and text() as shown here. You don't have to deal with tuples this way. As an example for a class User having the table name users you can try,

from sqlalchemy.sql import text

user = session.query(User).from_statement(
    text("""SELECT * FROM users where name=:name""")

return user

How do I compile and run a program in Java on my Mac?

Other solutions are good enough to answer your query. However, if you are looking for just one command to do that for you -

Create a file name "run", in directory where your Java files are. And save this in your file -

javac "$"
if [ $? -eq 0 ]; then
  echo "--------Run output-------"
  java "$1"

give this file run permission by running -

chmod 777 

Now you can run any of your files by merely running -

./run <yourfilename> (don't add .java in filename)

Scheduled run of stored procedure on SQL server

Probably not the answer you are looking for, but I find it more useful to simply use Windows Server Task Scheduler

You can use directly the command sqlcmd.exe -S "." -d YourDataBase -Q "exec SP_YourJob"

Or even create a .bat file. So you can even 2x click on the task on demand.

This has also been approached in this HERE

Map.Entry: How to use it?

A Map consists of key/value pairs. For example, in your code, one key is "Add" and the associated value is JButton("+"). A Map.Entry is a single key/value pair contained in the Map. It's two most-used methods are getKey() and getValue(). Your code gets all the pairs into a Set:

Set entrys = listbouton.entrySet() ;

and iterates over them. Now, it only looks at the value part using me.getValue() and adds them to your PanneauCalcul

this.add((Component) me.getValue()) ;   //don't understand

Often this type of loop (over the Map.Entry) makes sense if you need to look at both the key and the value. However, in your case, you aren't using the keys, so a far simpler version would be to just get all the values in your map and add them. e.g.

for (JButton jb:listbouton.values()) {

One final comment. The order of iteration in a HashMap is pretty random. So the buttons will be added to your PanneauCalcul in a semi-random order. If you want to preserve the order of the buttons, you should use a LinkedHashMap.

Get all attributes of an element using jQuery

with LoDash you could simply do this:

_.transform(this.attributes, function (result, item) {
  item.specified && (result[] = item.value);
}, {});

-bash: export: `=': not a valid identifier

I had the same problem and figured it out from your comments, but thought I would add the reason I caused the error to occur (for other beginners).

I had opened and edited .bash_profile using the open command in Terminal, which opened it in Text Editor. I typed in an addition to .bash_profile and it used improper quote characters. I opened .bash_profile in Atom and fixed up the error. I also associated the file with Atom for future editing.

how to get current location in google map android

All solution mentioned above using that code which are deprecated now!Here is the new solution

  1. Add implementation '' dependency in your gradle file

  2. Add network permission in your manifest file:

<uses-permission android:name="android.permission.INTERNET" /> <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" /> <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />

  1. Now use this code to get current location

      FusedLocationProviderClient mFusedLocationClient = LocationServices.getFusedLocationProviderClient(this);
      mFusedLocationClient.getLastLocation().addOnSuccessListener(new OnSuccessListener<Location>() {
                    public void onSuccess(Location location) {
                        // GPS location can be null if GPS is switched off
                            currentLat = location.getLatitude();
                            currentLong = location.getLongitude();
                            Toast.makeText(HomeNavigationBarActivtiy.this, "lat " + location.getLatitude() + "\nlong " + location.getLongitude(), Toast.LENGTH_SHORT).show();
                .addOnFailureListener(new OnFailureListener() {
                    public void onFailure(@NonNull Exception e) {

JAXB: how to marshall map into <key>value</key>

I have solution without adapter. Transient map converted to xml-elements and vise versa:

@XmlRootElement(name = "SchemaBasedProperties")
public class SchemaBasedProperties
  Map<String, Map<String, String>> properties;

  @XmlAnyElement(lax = true)
  List<Object> xmlmap;

  public Map<String, Map<String, String>> getProperties()
    if (properties == null)
      properties = new LinkedHashMap<String, Map<String, String>>(); // I want same order

    return properties;

  boolean beforeMarshal(Marshaller m)
      if (properties != null && !properties.isEmpty())
        if (xmlmap == null)
          xmlmap = new ArrayList<Object>();

        javax.xml.parsers.DocumentBuilderFactory dbf = javax.xml.parsers.DocumentBuilderFactory.newInstance();
        javax.xml.parsers.DocumentBuilder db = dbf.newDocumentBuilder();
        org.w3c.dom.Document doc = db.newDocument();
        org.w3c.dom.Element element;

        Map<String, String> attrs;

        for (Map.Entry<String, Map<String, String>> it: properties.entrySet())
          element = doc.createElement(it.getKey());
          attrs = it.getValue();

          if (attrs != null)
            for (Map.Entry<String, String> at: attrs.entrySet())
              element.setAttribute(at.getKey(), at.getValue());

        xmlmap = null;
    catch (Exception e)
      return false;

    return true;

  void afterUnmarshal(Unmarshaller u, Object p)
    org.w3c.dom.Node node;
    org.w3c.dom.NamedNodeMap nodeMap;

    String name;
    Map<String, String> attrs;


    if (xmlmap != null)
      for (Object xmlNode: xmlmap)
        if (xmlNode instanceof org.w3c.dom.Node)
          node = (org.w3c.dom.Node) xmlNode;
          nodeMap = node.getAttributes();

          name = node.getLocalName();
          attrs = new HashMap<String, String>();

          for (int i = 0, l = nodeMap.getLength(); i < l; i++)
            node = nodeMap.item(i);
            attrs.put(node.getNodeName(), node.getNodeValue());

          getProperties().put(name, attrs);

    xmlmap = null;

  public static void main(String[] args)
    throws Exception
    SchemaBasedProperties props = new SchemaBasedProperties();
    Map<String, String> attrs;

    attrs = new HashMap<String, String>();
    attrs.put("ResId", "A_LABEL");
    props.getProperties().put("LABEL", attrs);

    attrs = new HashMap<String, String>();
    attrs.put("ResId", "A_TOOLTIP");
    props.getProperties().put("TOOLTIP", attrs);

    attrs = new HashMap<String, String>();
    attrs.put("Value", "hide");
    props.getProperties().put("DISPLAYHINT", attrs);

    javax.xml.bind.JAXBContext jc = javax.xml.bind.JAXBContext.newInstance(SchemaBasedProperties.class);

    Marshaller marshaller = jc.createMarshaller();
    marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
    marshaller.marshal(props, new"test.xml"));

    Unmarshaller unmarshaller = jc.createUnmarshaller();
    props = (SchemaBasedProperties) unmarshaller.unmarshal(new"test.xml"));


My output as espected:

    <LABEL ResId="A_LABEL"/>
    <DISPLAYHINT Value="hide"/>


You can use element name/value pair. I need attributes... Have fun!

How to implement infinity in Java?

Only Double and Float type support POSITIVE_INFINITY constant.

Why shouldn't I use "Hungarian Notation"?

Joel Spolsky wrote a good blog post about this. Basically it comes down to not making your code harder to read when a decent IDE will tell you want type the variable is if you can't remember. Also, if you make your code compartmentalized enough, you don't have to remember what a variable was declared as three pages up.

Two way sync with rsync

Try this,

 rsync -avzru --delete-excluded server:/media/10001/music/ /media/Incoming/music/

 rsync -avzru --delete-excluded /media/Incoming/music/ server:/media/10001/music/

sync-music: get-music put-music

I just test this and it worked for me. I'm doing a 2-way sync between Windows7 (using cygwin with the rsync package installed) and FreeNAS fileserver (FreeNAS runs on FreeBSD with rsync package pre-installed).

"java.lang.OutOfMemoryError: PermGen space" in Maven build

Increase the size of your perm space, of course. Use the -XX:MaxPermSize=128m option. Set the value to something appropriate.

Generate Java class from JSON?

Answering this old question with recent project ;-).

At the moment the best solution is probably JsonSchema2Pojo :

It does the job from the seldom used Json Schema but also with plain Json. It provides Ant and Maven plugin and an online test application can give you an idea of the tool. I put a Json Tweet and generated all the containing class (Tweet, User, Location, etc..).

We'll use it on Agorava project to generate Social Media mapping and follow the contant evolution in their API.

pretty-print JSON using JavaScript

To highlight and beautify it in HTML using Bootstrap:

function prettifyJson(json, prettify) {
    if (typeof json !== 'string') {
        if (prettify) {
            json = JSON.stringify(json, undefined, 4);
        } else {
            json = JSON.stringify(json);
    return json.replace(/("(\\u[a-zA-Z0-9]{4}|\\[^u]|[^\\"])*"(\s*:)?|\b(true|false|null)\b|-?\d+(?:\.\d*)?(?:[eE][+\-]?\d+)?)/g,
        function(match) {
            let cls = "<span>";
            if (/^"/.test(match)) {
                if (/:$/.test(match)) {
                    cls = "<span class='text-danger'>";
                } else {
                    cls = "<span>";
            } else if (/true|false/.test(match)) {
                cls = "<span class='text-primary'>";
            } else if (/null/.test(match)) {
                cls = "<span class='text-info'>";
            return cls + match + "</span>";

Python regex to match dates

I built my solution on top of @aditya Prakash appraoch:


The first part (^([1-9]|0[1-9]|1[0-9]|2[0-9]|3[0-1])(\.|-|/)([1-9]|0[1-9]|1[0-2])(\.|-|/)([0-9][0-9]|19[0-9][0-9]|20[0-9][0-9])$) can handle the following formats:

  • 01.10.2019
  • 1.1.2019
  • 1.1.19
  • 12/03/2020
  • 01.05.1950

The second part (^([0-9][0-9]|19[0-9][0-9]|20[0-9][0-9])(\.|-|/)([1-9]|0[1-9]|1[0-2])(\.|-|/)([1-9]|0[1-9]|1[0-9]|2[0-9]|3[0-1])$) can basically do the same, but in inverse order, where the year comes first, followed by month, and then day.

  • 2020/02/12

As delimiters it allows ., /, -. As years it allows everything from 1900-2099, also giving only two numbers is fine.

If you have suggestions for improvement please let me know in the comments, so I can update the answer.

C# Parsing JSON array of objects

I believe this is much simpler;

dynamic obj = JObject.Parse(jsonString);
string results  = obj.results;
foreach(string result in result.Split('))

Play a Sound with Python

I like pygame, and the command below should work:


but it doesn't on either of my computers, and there is limited help on the subject out there. edit: I figured out why the pygame sound isn't working for me, it's not loading most sounds correctly, the 'length' attribute is ~0.0002 when I load them. maybe loading them using something other than mygame will get it morking more generally.

with pyglet I'm getting a resource not found error Using the above example, wigh both relative and full paths to the files.

using instead of lets me load the files.

but only plays the first fraction of a second of the file, unless I run which blocks everything else...

Open soft keyboard programmatically

Post this method in your base activity and use it other activities like a charm

public void openKeyboard() {
    InputMethodManager imm =
            (InputMethodManager) getSystemService(Context.INPUT_METHOD_SERVICE);
    if (imm != null) {
        imm.toggleSoftInput(InputMethodManager.SHOW_FORCED, 0);

How to change the buttons text using javascript

I know this question has been answered but I also see there is another way missing which I would like to cover it.There are multiple ways to achieve this.

1- innerHTML

document.getElementById("ShowButton").innerHTML = 'Show Filter';

You can insert HTML into this. But the disadvantage of this method is, it has cross site security attacks. So for adding text, its better to avoid this for security reasons.

2- innerText

document.getElementById("ShowButton").innerText = 'Show Filter';

This will also achieve the result but its heavy under the hood as it requires some layout system information, due to which the performance decreases. Unlike innerHTML, you cannot insert the HTML tags with this. Check Performance Here

3- textContent

document.getElementById("ShowButton").textContent = 'Show Filter';

This will also achieve the same result but it doesn't have security issues like innerHTML as it doesn't parse HTML like innerText. Besides, it is also light due to which performance increases.

So if a text has to be added like above, then its better to use textContent.

How can I display the users profile pic using the facebook graph api?

I was having a problem fetching profile photos while using CURL. I thought for a while there was something wrong my implementation of the Facebook API, but I need to add a bit to my CURL called:

curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);

Sorting an array of objects by property values

While it is a bit of an overkill for just sorting a single array, this prototype function allows to sort Javascript arrays by any key, in ascending or descending order, including nested keys, using dot syntax.

    var keyPaths = [];

    var saveKeyPath = function(path) {
            sign: (path[0] === '+' || path[0] === '-')? parseInt(path.shift()+1) : 1,
            path: path

    var valueOf = function(object, path) {
        var ptr = object;
        for (var i=0,l=path.length; i<l; i++) ptr = ptr[path[i]];
        return ptr;

    var comparer = function(a, b) {
        for (var i = 0, l = keyPaths.length; i < l; i++) {
            aVal = valueOf(a, keyPaths[i].path);
            bVal = valueOf(b, keyPaths[i].path);
            if (aVal > bVal) return keyPaths[i].sign;
            if (aVal < bVal) return -keyPaths[i].sign;
        return 0;

    Array.prototype.sortBy = function() {
        keyPaths = [];
        for (var i=0,l=arguments.length; i<l; i++) {
            switch (typeof(arguments[i])) {
                case "object": saveKeyPath(arguments[i]); break;
                case "string": saveKeyPath(arguments[i].match(/[+-]|[^.]+/g)); break;
        return this.sort(comparer);


var data = [
    { name: { first: 'Josh', last: 'Jones' }, age: 30 },
    { name: { first: 'Carlos', last: 'Jacques' }, age: 19 },
    { name: { first: 'Carlos', last: 'Dante' }, age: 23 },
    { name: { first: 'Tim', last: 'Marley' }, age: 9 },
    { name: { first: 'Courtney', last: 'Smith' }, age: 27 },
    { name: { first: 'Bob', last: 'Smith' }, age: 30 }

data.sortBy('age'); // "Tim Marley(9)", "Carlos Jacques(19)", "Carlos Dante(23)", "Courtney Smith(27)", "Josh Jones(30)", "Bob Smith(30)"

Sorting by nested properties with dot-syntax or array-syntax:

data.sortBy('name.first'); // "Bob Smith(30)", "Carlos Dante(23)", "Carlos Jacques(19)", "Courtney Smith(27)", "Josh Jones(30)", "Tim Marley(9)"
data.sortBy(['name', 'first']); // "Bob Smith(30)", "Carlos Dante(23)", "Carlos Jacques(19)", "Courtney Smith(27)", "Josh Jones(30)", "Tim Marley(9)"

Sorting by multiple keys:

data.sortBy('name.first', 'age'); // "Bob Smith(30)", "Carlos Jacques(19)", "Carlos Dante(23)", "Courtney Smith(27)", "Josh Jones(30)", "Tim Marley(9)"
data.sortBy('name.first', '-age'); // "Bob Smith(30)", "Carlos Dante(23)", "Carlos Jacques(19)", "Courtney Smith(27)", "Josh Jones(30)", "Tim Marley(9)"

You can fork the repo:

How to start automatic download of a file in Internet Explorer?

I hate when sites complicate download so much and use hacks instead of a good old link.

Dead simple version:

<a href="">Start automatic download!</a>

It works! In every browser!

If you want to download a file that is usually displayed inline (such as an image) then HTML5 has a download attribute that forces download of the file. It also allows you to override filename (although there is a better way to do it):

<a href="report-generator.php" download="result.xls">Download</a>

Version with a "thanks" page:

If you want to display "thanks" after download, then use:

<a href="" 
   onclick="if (event.button==0) 
 Start automatic download!

Function in that setTimeout might be more advanced and e.g. download full page via AJAX (but don't navigate away from the page — don't touch window.location or activate other links).

The point is that link to download is real, can be copied, dragged, intercepted by download accelerators, gets :visited color, doesn't re-download if page is left open after browser restart, etc.

That's what I use for ImageOptim

Cross-Origin Request Blocked

You need other headers, not only access-control-allow-origin. If your request have the "Access-Control-Allow-Origin" header, you must copy it into the response headers, If doesn't, you must check the "Origin" header and copy it into the response. If your request doesn't have Access-Control-Allow-Origin not Origin headers, you must return "*".

You can read the complete explanation here:

and this is the function I'm using to write cross domain headers:

func writeCrossDomainHeaders(w http.ResponseWriter, req *http.Request) {
    // Cross domain headers
    if acrh, ok := req.Header["Access-Control-Request-Headers"]; ok {
        w.Header().Set("Access-Control-Allow-Headers", acrh[0])
    w.Header().Set("Access-Control-Allow-Credentials", "True")
    if acao, ok := req.Header["Access-Control-Allow-Origin"]; ok {
        w.Header().Set("Access-Control-Allow-Origin", acao[0])
    } else {
        if _, oko := req.Header["Origin"]; oko {
            w.Header().Set("Access-Control-Allow-Origin", req.Header["Origin"][0])
        } else {
            w.Header().Set("Access-Control-Allow-Origin", "*")
    w.Header().Set("Access-Control-Allow-Methods", "GET, POST, PUT, DELETE")
    w.Header().Set("Connection", "Close")


Error: select command denied to user '<userid>'@'<ip-address>' for table '<table-name>'

For me, I accidentally included my local database name inside the SQL query, hence the access denied issue came up when I deployed.

I removed the database name from the SQL query and it got fixed.

Why Git is not allowing me to commit even after configuration?

I had this problem even after setting the config properly. git config

My scenario was issuing git command through supervisor (in Linux). On further debugging, supervisor was not reading the git config from home folder. Hence, I had to set the environment HOME variable in the supervisor config so that it can locate the git config correctly. It's strange that supervisor was not able to locate the git config just from the username configured in supervisor's config (/etc/supervisor/conf.d).

Order discrete x scale by frequency/value

Hadley has been developing a package called forcats. This package makes the task so much easier. You can exploit fct_infreq() when you want to change the order of x-axis by the frequency of a factor. In the case of the mtcars example in this post, you want to reorder levels of cyl by the frequency of each level. The level which appears most frequently stays on the left side. All you need is the fct_infreq().


ggplot(mtcars, aes(fct_infreq(factor(cyl)))) +
geom_bar() +
labs(x = "cyl")

If you wanna go the other way around, you can use fct_rev() along with fct_infreq().

ggplot(mtcars, aes(fct_rev(fct_infreq(factor(cyl))))) +
geom_bar() +
labs(x = "cyl") 

enter image description here

Is there any native DLL export functions viewer?

If you don't have the source code and API documentation, the machine code is all there is, you need to disassemble the dll library using something like IDA Pro , another option is use the trial version of PE Explorer.

PE Explorer provides a Disassembler. There is only one way to figure out the parameters: run the disassembler and read the disassembly output. Unfortunately, this task of reverse engineering the interface cannot be automated.

PE Explorer comes bundled with descriptions for 39 various libraries, including the core Windows® operating system libraries (eg. KERNEL32, GDI32, USER32, SHELL32, WSOCK32), key graphics libraries (DDRAW, OPENGL32) and more.

alt text

How to format DateTime columns in DataGridView?

If it is a windows form Datagrid, you could use the below code to format the datetime for a column

dataGrid.Columns[2].DefaultCellStyle.Format = "MM/dd/yyyy HH:mm:ss";


Apart from this, if you need the datetime in AM/PM format, you could use the below code

dataGrid.Columns[2].DefaultCellStyle.Format = "MM/dd/yyyy hh:mm:ss tt";

Shuffling a list of objects

>>> import random
>>> a = ['hi','world','cat','dog']
>>> random.shuffle(a,random.random)
>>> a
['hi', 'cat', 'dog', 'world']

It works fine for me. Make sure to set the random method.

Extract values in Pandas value_counts()

Try this:

['apple', 'sausage', 'banana', 'cheese']

Convert Unicode to ASCII without errors in Python

unicodestring = '\xa0'

decoded_str = unicodestring.decode("windows-1252")
encoded_str = decoded_str.encode('ascii', 'ignore')

Works for me

ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: YES)

I tried with the correct answer by @Lahiru, but did not work with MySQL server version 8.0.16 (Community) on macOS Mojave.

Followed the instructions by Sameer Choudhary above and with some adjustments, I was able to change root password and enable root access from localhost.

Update: All of these are not required, if you are installing on Mac OS using homebrew: "brew install mysql"

Why is Dictionary preferred over Hashtable in C#?

Collections & Generics are useful for handling group of objects. In .NET, all the collections objects comes under the interface IEnumerable, which in turn has ArrayList(Index-Value)) & HashTable(Key-Value). After .NET framework 2.0, ArrayList & HashTable were replaced with List & Dictionary. Now, the Arraylist & HashTable are no more used in nowadays projects.

Coming to the difference between HashTable & Dictionary, Dictionary is generic where as Hastable is not Generic. We can add any type of object to HashTable, but while retrieving we need to cast it to the required type. So, it is not type safe. But to dictionary, while declaring itself we can specify the type of key and value, so there is no need to cast while retrieving.

Let's look at an example:


class HashTableProgram
    static void Main(string[] args)
        Hashtable ht = new Hashtable();
        ht.Add(1, "One");
        ht.Add(2, "Two");
        ht.Add(3, "Three");
        foreach (DictionaryEntry de in ht)
            int Key = (int)de.Key; //Casting
            string value = de.Value.ToString(); //Casting
            Console.WriteLine(Key + " " + value);



class DictionaryProgram
    static void Main(string[] args)
        Dictionary<int, string> dt = new Dictionary<int, string>();
        dt.Add(1, "One");
        dt.Add(2, "Two");
        dt.Add(3, "Three");
        foreach (KeyValuePair<int, String> kv in dt)
            Console.WriteLine(kv.Key + " " + kv.Value);

Disabling radio buttons with jQuery

I've refactored your code a bit, this should work:


function writeData() {
    jQuery("#chatTickets input:radio").attr('disabled',true);

If there are more than two radio buttons on your form, you'll have to modify the selector, for example, you can use the starts with attribute filter to pick out the radios whose ID starts with ticketID:

function writeData() {
    jQuery("#chatTickets input[id^=ticketID]:radio").attr('disabled',true);

Programmatically navigate using react router V4

As sometimes I prefer to switch routes by Application then by buttons, this is a minimal working example what works for me:

import { Component } from 'react'
import { BrowserRouter as Router, Link } from 'react-router-dom'

class App extends Component {
  constructor(props) {

    /** @type BrowserRouter */
    this.router = undefined

  async handleSignFormSubmit() {
    await magic()

  render() {
    return (
      <Router ref={ el => this.router = el }>
        <Link to="/signin">Sign in</Link>
        <Route path="/signin" exact={true} render={() => (
          <SignPage onFormSubmit={ this.handleSignFormSubmit } />
        )} />

Eclipse 3.5 Unable to install plugins

i fought with eclipse 3.5.0 (galileo) for days, i had to use this version because I am doing blackberry development and eclipse comes bundle with blackberry specifics so i need to use the package they bundled, which was not 3.5.0 (not the 3.5.1) , BUT SirFabel saved the day, thanks to all who contributed to this post

I used 3.5.0 and did "Set the following system property in you eclipse.ini file: -Dorg.eclipse.ecf.provider.filetransfer.excludeContributors=org.eclipse.ecf.provider.filetransfer.httpclient For more details on this:… - Configure only the HTTP and HTTPS proxies. Not SOCKS!! "

and I am able to get through my companies proxy!!!!

How to install Flask on Windows?

Install pip as described here: How do I install pip on Windows?

Then do

pip install flask

That installation tutorial is a bit misleading, it refers to actually running it in a production environment.

How to build an android library with Android Studio and gradle?

I just had a very similar issues with gradle builds / adding .jar library. I got it working by a combination of :

  1. Moving the libs folder up to the root of the project (same directory as 'src'), and adding the library to this folder in finder (using Mac OS X)
  2. In Android Studio, Right-clicking on the folder to add as library
  3. Editing the dependencies in the build.gradle file, adding compile fileTree(dir: 'libs', include: '*.jar')}

BUT more importantly and annoyingly, only hours after I get it working, Android Studio have just released 0.3.7, which claims to have solved a lot of gradle issues such as adding .jar libraries

Hope this helps people!

moment.js 24h format

Try: moment({ // Options here }).format('HHmm'). That should give you the time in a 24 hour format.

jQuery toggle animation

onmouseover="$('.play-detail').stop().animate({'height': '84px'},'300');" 

onmouseout="$('.play-detail').stop().animate({'height': '44px'},'300');"

Just put two stops -- one onmouseover and one onmouseout.

What exactly are iterator, iterable, and iteration?

Here's my cheat sheet:

   def __getitem__(self, index: int):
  +    ...
  |    raise IndexError
  |              def __iter__(self):
  |             +     ...
  |             |     return <iterator>
  |             |
  |             |
  +--> or <-----+        def __next__(self):
       +        |       +    ...
       |        |       |    raise StopIteration
       v        |       |
    iterable    |       |
           +    |       |
           |    |       v
           |    +----> and +-------> iterator
           |                               ^
           v                               |
   iter(<iterable>) +----------------------+
   def generator():                        |
  +    yield 1                             |
  |                 generator_expression +-+
  |                                        |
  +-> generator() +-> generator_iterator +-+

Quiz: Do you see how...

  1. every iterator is an iterable?
  2. a container object's __iter__() method can be implemented as a generator?
  3. an iterable that has a __next__ method is not necessarily an iterator?


  1. Every iterator must have an __iter__ method. Having __iter__ is enough to be an iterable. Therefore every iterator is an iterable.
  2. When __iter__ is called it should return an iterator (return <iterator> in the diagram above). Calling a generator returns a generator iterator which is a type of iterator.

    class Iterable1:
        def __iter__(self):
            # a method (which is a function defined inside a class body)
            # calling iter() converts iterable (tuple) to iterator
            return iter((1,2,3))
    class Iterable2:
        def __iter__(self):
            # a generator
            for i in (1, 2, 3):
                yield i
    class Iterable3:
        def __iter__(self):
            # with PEP 380 syntax
            yield from (1, 2, 3)
    # passes
    assert list(Iterable1()) == list(Iterable2()) == list(Iterable3()) == [1, 2, 3]
  3. Here is an example:

    class MyIterable:
        def __init__(self):
            self.n = 0
        def __getitem__(self, index: int):
            return (1, 2, 3)[index]
        def __next__(self):
            n = self.n = self.n + 1
            if n > 3:
                raise StopIteration
            return n
    # if you can iter it without raising a TypeError, then it's an iterable.
    # but obviously `MyIterable()` is not an iterator since it does not have
    # an `__iter__` method.
    from import Iterator
    assert isinstance(MyIterable(), Iterator)  # AssertionError

Macro to Auto Fill Down to last adjacent cell

Untested....but should work.

Dim lastrow as long

lastrow = range("D65000").end(xlup).Row

ActiveCell.FormulaR1C1 = _
        "=IF(MONTH(RC[-1])>3,"" ""&YEAR(RC[-1])&""-""&RIGHT(YEAR(RC[-1])+1,2),"" ""&YEAR(RC[-1])-1&""-""&RIGHT(YEAR(RC[-1]),2))"
    Selection.AutoFill Destination:=Range("E2:E" & lastrow)
    'Selection.AutoFill Destination:=Range("E2:E"& lastrow)

Only exception being are you sure your Autofill code is perfect...

SQL Query for Student mark functionality

SQL> select * from stud;

 STUDENTID NAME                           DETAILS
---------- ------------------------------ ------------------------------
         1 Alfred                         AA
         2 Betty                          BB
         3 Chris                          CC

SQL> select * from subject;

---------- ------------------------------
         1 Maths
         2 Science
         3 English

SQL> select * from marks;

---------- ---------- ----------
         1          1         61
         1          2         75
         1          3         87
         2          1         82
         2          2         64
         2          3         77
         3          1         82
         3          2         83
         3          3         67

9 rows selected.

SQL> select name, subjectid, mark
  2  from (select name, subjectid, mark, dense_rank() over(partition by subjectid order by mark desc) rank
  3  from stud st, marks mk
  4  where st.studentid=mk.studentid)
  5  where rank=1;

NAME                            SUBJECTID       MARK
------------------------------ ---------- ----------
Betty                                   1         82
Chris                                   1         82
Chris                                   2         83
Alfred                                  3         87


TypeError: 'function' object is not subscriptable - Python

You have two objects both named bank_holiday -- one a list and one a function. Disambiguate the two.

bank_holiday[month] is raising an error because Python thinks bank_holiday refers to the function (the last object bound to the name bank_holiday), whereas you probably intend it to mean the list.

Oracle 11g Express Edition for Windows 64bit?

There is

I used this blog post to install it in my machine:

The only thing you have to do is replace a registry value during the installation, I've done it about three times already, and every time found a different reference on-line, none here on stackoverflow.

EDIT: as @kc2001 noted, regedit must be run as Administrator, and added this tutorial: (a bit more colorful):

How to vertically center a "div" element for all browsers using CSS?

The best thing to do would be:

  height: 300px;
  width: 300px;
  position: absolute;
  top: calc(50vh - 150px); 

150 pixels because that's half of the div's height in this case.

Requests -- how to tell if you're getting a 404

Look at the r.status_code attribute:

if r.status_code == 404:
    # A 404 was issued.


>>> import requests
>>> r = requests.get('')
>>> r.status_code

If you want requests to raise an exception for error codes (4xx or 5xx), call r.raise_for_status():

>>> r = requests.get('')
>>> r.raise_for_status()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "requests/", line 664, in raise_for_status
    raise http_error
requests.exceptions.HTTPError: 404 Client Error: NOT FOUND
>>> r = requests.get('')
>>> r.raise_for_status()
>>> # no exception raised.

You can also test the response object in a boolean context; if the status code is not an error code (4xx or 5xx), it is considered ‘true’:

if r:
    # successful response

If you want to be more explicit, use if r.ok:.

How to get the first column of a pandas DataFrame as a Series?

Isn't this the simplest way?

By column name:

In [20]: df = pd.DataFrame({'x' : [1, 2, 3, 4], 'y' : [4, 5, 6, 7]})
In [21]: df
    x   y
0   1   4
1   2   5
2   3   6
3   4   7

In [23]: df.x
0    1
1    2
2    3
3    4
Name: x, dtype: int64

In [24]: type(df.x)

Line Break in XML formatting?

Here is what I use when I don't have access to the source string, e.g. for downloaded HTML:

// replace newlines with <br>
public static String replaceNewlinesWithBreaks(String source) {
    return source != null ? source.replaceAll("(?:\n|\r\n)","<br>") : "";

For XML you should probably edit that to replace with <br/> instead.

Example of its use in a function (additional calls removed for clarity):

// remove HTML tags but preserve supported HTML text styling (if there is any)
public static CharSequence getStyledTextFromHtml(String source) {
    return android.text.Html.fromHtml(replaceNewlinesWithBreaks(source));

...and a further example:


How do I remove a MySQL database?

drop database <db_name>;

How to use cURL to get jSON data and decode the data?

You can Use this for Curl:

function fakeip()  
    return long2ip( mt_rand(0, 65537) * mt_rand(0, 65535) );   

function getdata($url,$args=false) 
    global $session; 
    $ch = curl_init(); 
    curl_setopt($ch, CURLOPT_URL,$url); 
    curl_setopt($ch, CURLOPT_HTTPHEADER, array("REMOTE_ADDR: ".fakeip(),"X-Client-IP: ".fakeip(),"Client-IP: ".fakeip(),"HTTP_X_FORWARDED_FOR: ".fakeip(),"X-Forwarded-For: ".fakeip())); 
        curl_setopt($ch, CURLOPT_POST, 1); 
        curl_setopt($ch, CURLOPT_POSTFIELDS,$args); 
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true); 
    //curl_setopt($ch, CURLOPT_PROXY, ""); 
    $result = curl_exec ($ch); 
    curl_close ($ch); 
    return $result; 

Then To Read Json:


Then :

///Deocde Json
$data = json_decode($result,true);
             $Str='<h1>Total : '.$total.'';
             echo $Str;
//You Can Also Make In Table:
             foreach ($data as $key => $value)
          echo '  <td><font  face="calibri"color="red">'.$value[type].'   </font></td><td><font  face="calibri"color="blue">'.$value[category].'   </font></td><td><font  face="calibri"color="green">'.$value[amount].'   </font></tr><tr>';

           echo "</tr></table>";

You Can Also Use This:

echo '<p>Name : '.$data['result']['name'].'</p>
      <img src="'.$data['result']['pic'].'"><br>';

Hope this helped.

How to find where gem files are installed

You can check it from your command prompt by running gem help commands and then selecting the proper command:

kirti@kirti-Aspire-5733Z:~$  gem help commands
GEM commands are:

    build                  Build a gem from a gemspec
    cert                   Manage RubyGems certificates and signing settings
    check                  Check a gem repository for added or missing files
    cleanup                Clean up old versions of installed gems in the local
    contents               Display the contents of the installed gems
    dependency             Show the dependencies of an installed gem
    environment            Display information about the RubyGems environment
    fetch                  Download a gem and place it in the current directory
    generate_index         Generates the index files for a gem server directory
    help                   Provide help on the 'gem' command
    install                Install a gem into the local repository
    list                   Display gems whose name starts with STRING
    lock                   Generate a lockdown list of gems
    mirror                 Mirror all gem files (requires rubygems-mirror)
    outdated               Display all gems that need updates
    owner                  Manage gem owners on
    pristine               Restores installed gems to pristine condition from
                           files located in the gem cache
    push                   Push a gem up to
    query                  Query gem information in local or remote repositories
    rdoc                   Generates RDoc for pre-installed gems
    regenerate_binstubs    Re run generation of executable wrappers for gems.
    search                 Display all gems whose name contains STRING
    server                 Documentation and gem repository HTTP server
    sources                Manage the sources and cache file RubyGems uses to
                           search for gems
    specification          Display gem specification (in yaml)
    stale                  List gems along with access times
    uninstall              Uninstall gems from the local repository
    unpack                 Unpack an installed gem to the current directory
    update                 Update installed gems to the latest version
    which                  Find the location of a library file you can require
    yank                   Remove a specific gem version release from

For help on a particular command, use 'gem help COMMAND'.

Commands may be abbreviated, so long as they are unambiguous.
e.g. 'gem i rake' is short for 'gem install rake'.

Now from the above I can see the command environment is helpful. So I would do:

kirti@kirti-Aspire-5733Z:~$ gem help environment
Usage: gem environment [arg] [options]

  Common Options:
    -h, --help                       Get help on this command
    -V, --[no-]verbose               Set the verbose level of output
    -q, --quiet                      Silence commands
        --config-file FILE           Use this config file instead of default
        --backtrace                  Show stack backtrace on errors
        --debug                      Turn on Ruby debugging

    packageversion  display the package version
    gemdir          display the path where gems are installed
    gempath         display path used to search for gems
    version         display the gem format version
    remotesources   display the remote gem servers
    platform        display the supported gem platforms
    <omitted>       display everything

    Display information about the RubyGems environment

    The RubyGems environment can be controlled through command line arguments,
    gemrc files, environment variables and built-in defaults.

    Command line argument defaults and some RubyGems defaults can be set in a
    ~/.gemrc file for individual users and a /etc/gemrc for all users. These
    files are YAML files with the following YAML keys:

      :sources: A YAML array of remote gem repositories to install gems from
      :verbose: Verbosity of the gem command. false, true, and :really are the
      :update_sources: Enable/disable automatic updating of repository metadata
      :backtrace: Print backtrace when RubyGems encounters an error
      :gempath: The paths in which to look for gems
      :disable_default_gem_server: Force specification of gem server host on
      <gem_command>: A string containing arguments for the specified gem command


      :verbose: false
      install: --no-wrappers
      update: --no-wrappers
      :disable_default_gem_server: true

    RubyGems' default local repository can be overridden with the GEM_PATH and
    GEM_HOME environment variables. GEM_HOME sets the default repository to
    install into. GEM_PATH allows multiple local repositories to be searched for

    If you are behind a proxy server, RubyGems uses the HTTP_PROXY,
    HTTP_PROXY_USER and HTTP_PROXY_PASS environment variables to discover the
    proxy server.

    If you would like to push gems to a private gem server the RUBYGEMS_HOST
    environment variable can be set to the URI for that server.

    If you are packaging RubyGems all of RubyGems' defaults are in
    lib/rubygems/defaults.rb.  You may override these in

Finally to show you what you asked, I would do:

kirti@kirti-Aspire-5733Z:~$ gem environment gemdir
kirti@kirti-Aspire-5733Z:~$ gem environment gempath

Clone private git repo with dockerfile

Above solutions did not work for bitbucket. I figured this does the trick:

RUN ssh-keyscan >> /root/.ssh/known_hosts \
    && eval `ssh-agent` \
    && ssh-add ~/.ssh/[key] \
    && git clone [email protected]:[team]/[repo].git

How do I concatenate or merge arrays in Swift?

Here's the shortest way to merge two arrays.

 var array1 = [1,2,3]
 let array2 = [4,5,6]

Concatenate/merge them

array1 += array2
New value of array1 is [1,2,3,4,5,6]

WordPress query single post by slug

As wordpress api has changed, you can´t use get_posts with param 'post_name'. I´ve modified Maartens function a bit:

function get_post_id_by_slug( $slug, $post_type = "post" ) {
    $query = new WP_Query(
            'name'   => $slug,
            'post_type'   => $post_type,
            'numberposts' => 1,
            'fields'      => 'ids',
        ) );
    $posts = $query->get_posts();
    return array_shift( $posts );

Pandas Merge - How to avoid duplicating columns

You can work out the columns that are only in one DataFrame and use this to select a subset of columns in the merge.

cols_to_use = df2.columns.difference(df.columns)

Then perform the merge (note this is an index object but it has a handy tolist() method).

dfNew = merge(df, df2[cols_to_use], left_index=True, right_index=True, how='outer')

This will avoid any columns clashing in the merge.

How to make sure that a certain Port is not occupied by any other process

It's (Get-NetTCPConnection -LocalPort "port no.").OwningProcess

How to set top position using jquery

Just for reference, if you are using:


To get the position, it can be affected by the position of the parent element. Thus you may want to be consistent and use the following to set it:

$(el).offset({top: pos});

As opposed to the CSS methods above.

How to connect TFS in Visual Studio code

Just as Daniel said "Git and TFVC are the two source control options in TFS". Fortunately both are supported for now in VS Code.

You need to install the Azure Repos Extension for Visual Studio Code. The process of installing is pretty straight forward.

  1. Search for Azure Repos in VS Code and select to install the one by Microsoft
  2. Open File -> Preferences -> Settings
  3. Add the following lines to your user settings

    If you have VS 2015 installed on your machine, your path to Team Foundation tool (tf.exe) may look like this:

        "tfvc.location": "C:\\Program Files (x86)\\Microsoft Visual Studio 14.0\\Common7\\IDE\\tf.exe",
        "tfvc.restrictWorkspace": true

    Or for VS 2017:

        "tfvc.location": "C:\\Program Files (x86)\\Microsoft Visual Studio\\2017\\Enterprise\\Common7\\IDE\\CommonExtensions\\Microsoft\\TeamFoundation\\Team Explorer\\tf.exe",
        "tfvc.restrictWorkspace": true
  4. Open a local folder (repository), From View -> Command Pallette ..., type team signin

  5. Provide user name --> Enter --> Provide password to connect to TFS.

Please refer to below links for more details:

Note that Server Workspaces are not supported:

"TFVC support is limited to Local workspaces":

on installing Azure extension, visual studio code warns you "It appears you are using a Server workspace. Currently, TFVC support is limited to Local workspaces"

Test if a command outputs an empty string

Here's a solution for more extreme cases:

if [ `command | head -c1 | wc -c` -gt 0 ]; then ...; fi

This will work

  • for all Bourne shells;
  • if the command output is all zeroes;
  • efficiently regardless of output size;


  • the command or its subprocesses will be killed once anything is output.

Set cookies for cross origin requests

Note for Chrome Browser released in 2020.

A future release of Chrome will only deliver cookies with cross-site requests if they are set with SameSite=None and Secure.

So if your backend server does not set SameSite=None, Chrome will use SameSite=Lax by default and will not use this cookie with { withCredentials: true } requests.

More info

Firefox and Edge developers also want to release this feature in the future.

Spec found here:

Unable to run Java GUI programs with Ubuntu

In my case


was set (indirectly by a Maven configuration). I had to actively use


to override this.

Socket.IO - how do I get a list of connected sockets/clients?

After 1.0 we cannot use


anymore. Instead you can use the following

var clients_in_the_room = io.sockets.adapter.rooms[roomId]; 
for (var clientId in clients_in_the_room ) {
  console.log('client: %s', clientId); //Seeing is believing 
  var client_socket = io.sockets.connected[clientId];//Do whatever you want with this

Multiple INSERT statements vs. single INSERT with multiple VALUES

I ran into a similar situation trying to convert a table with several 100k rows with a C++ program (MFC/ODBC).

Since this operation took a very long time, I figured bundling multiple inserts into one (up to 1000 due to MSSQL limitations). My guess that a lot of single insert statements would create an overhead similar to what is described here.

However, it turns out that the conversion took actually quite a bit longer:

        Method 1       Method 2     Method 3 
        Single Insert  Multi Insert Joined Inserts
Rows    1000           1000         1000
Insert  390 ms         765 ms       270 ms
per Row 0.390 ms       0.765 ms     0.27 ms

So, 1000 single calls to CDatabase::ExecuteSql each with a single INSERT statement (method 1) are roughly twice as fast as a single call to CDatabase::ExecuteSql with a multi-line INSERT statement with 1000 value tuples (method 2).

Update: So, the next thing I tried was to bundle 1000 separate INSERT statements into a single string and have the server execute that (method 3). It turns out this is even a bit faster than method 1.

Edit: I am using Microsoft SQL Server Express Edition (64-bit) v10.0.2531.0

How to make child process die after parent exits?

Does the child process have a pipe to/from the parent process? If so, you'd receive a SIGPIPE if writing, or get EOF when reading - these conditions could be detected.

MySQL Data Source not appearing in Visual Studio

i install mysql for visual studio and the problem simply solved.although version of my visual studio is 2012!

Getting HTTP headers with Node.js

I had some problems with http.get; so I switched to the lib request:

var request = require('request');

var url = '';

var options = {
    url: url,
    method: 'HEAD'

request(options, function (error, response, body) {
        if (error) {
            return console.error('upload failed:', error);

        if (response.headers['content-length']) {
            var file_size = response.headers['content-length'];

Check play state of AVPlayer

The Swift version of maxkonovalov's answer is this:

player.addObserver(self, forKeyPath: "rate", options: NSKeyValueObservingOptions.New, context: nil)


override func observeValueForKeyPath(keyPath: String?, ofObject object: AnyObject?, change: [String : AnyObject]?, context: UnsafeMutablePointer<Void>) {
    if keyPath == "rate" {
        if let rate = change?[NSKeyValueChangeNewKey] as? Float {
            if rate == 0.0 {
                print("playback stopped")
            if rate == 1.0 {
                print("normal playback")
            if rate == -1.0 {
                print("reverse playback")

Thank you maxkonovalov!

How do you push a tag to a remote repository using Git?

I am using git push <remote-name> tag <tag-name> to ensure that I am pushing a tag. I use it like: git push origin tag v1.0.1. This pattern is based upon the documentation (man git-push):

       tag <tag> means the same as refs/tags/<tag>:refs/tags/<tag>.

Javascript Equivalent to C# LINQ Select

You can try manipula package, which implement all of C# LINQ methods and save its syntax:

Your example>; will be implemented with manipula as


How can I make my custom objects Parcelable?

Here is a website to create a Parcelable Class from your created class:

What properties can I use with

window.onclick = e => {
    console.dir(;  // use this in chrome
    console.log(;  // use this in firefox - click on tag name to view 

enter image description here

take advantage of using filter propeties  // its not the value applied from the css style sheet, to get that values use `getComputedStyle()`

How to SELECT based on value of another SELECT

If you want to SELECT based on the value of another SELECT, then you probably want a "subselect":

For example, (from the link above):

  1. You want the first and last names from table "student_details" ...

  2. But you only want this information for those students in "science" class:

     SELECT id, first_name
     FROM student_details
     WHERE first_name IN (SELECT first_name
     FROM student_details
     WHERE subject= 'Science'); 

Frankly, I'm not sure this is what you're looking for or not ... but I hope it helps ... at least a little...


onClick function of an input type="button" not working

You have to change the ID of the button to be different from the function name JSFiddle

var counter = 0;_x000D_
function moreFields() {_x000D_
  var newFields = document.getElementById('readroot').cloneNode(true);_x000D_ = '';_x000D_ = 'block';_x000D_
  var newField = newFields.childNodes;_x000D_
  for (var i = 0; i < newField.length; i++) {_x000D_
    var theName = newField[i].name_x000D_
    if (theName) newField[i].name = theName + counter;_x000D_
  var insertHere = document.getElementById('writeroot');_x000D_
  insertHere.parentNode.insertBefore(newFields, insertHere);_x000D_
window.onload = moreFields();
<div id="readroot" style="display: none">_x000D_
  <input type="button" value="Remove review" onclick="this.parentNode.parentNode.removeChild(this.parentNode);" />_x000D_
  <br />_x000D_
  <br />_x000D_
  <input name="cd" value="title" />_x000D_
  <select name="rankingsel">_x000D_
    <option value="excellent">Excellent</option>_x000D_
    <option value="good">Good</option>_x000D_
    <option value="ok">OK</option>_x000D_
    <option value="poor">Poor</option>_x000D_
    <option value="bad">Bad</option>_x000D_
  <br />_x000D_
  <br />_x000D_
  <textarea rows="5" cols="20" name="review">Short review</textarea>_x000D_
  <br />Radio buttons included to test them in Explorer:_x000D_
  <br />_x000D_
  <input type="radio" name="something" value="test1" />Test 1_x000D_
  <br />_x000D_
  <input type="radio" name="something" value="test2" />Test 2</div>_x000D_
<form method="post" action="index1.php"> <span id="writeroot"></span>_x000D_
  <input type="button" onclick="moreFields();" id="moreFieldsButton" value="Give me more fields!" />_x000D_
  <input type="submit" value="Send form" />_x000D_

A url resource that is a dot (%2E)

It is not possible. §2.3 says that "." is an unreserved character and that "URIs that differ in the replacement of an unreserved character with its corresponding percent-encoded US-ASCII octet are equivalent". Therefore, /%2E%2E/ is the same as /../, and that will get normalized away.

(This is a combination of an answer by bobince and a comment by slowpoison.)

Xcode process launch failed: Security

BTW, this also happens if you change the team of your target in Xcode and rebuild. Was quite puzzled to see that problem with an app that I had run on the device before. Took me a while to figure out… Might only happen the first time building to a device with a team, though.

VBA copy rows that meet criteria to another sheet

You need to specify workseet. Change line

If Worksheet.Cells(i, 1).Value = "X" Then


If Worksheets("Sheet2").Cells(i, 1).Value = "X" Then


Try to use following code (but it's not the best approach. As @SiddharthRout suggested, consider about using Autofilter):

Sub LastRowInOneColumn()
   Dim LastRow As Long
   Dim i As Long, j As Long

   'Find the last used row in a Column: column A in this example
   With Worksheets("Sheet2")
      LastRow = .Cells(.Rows.Count, "A").End(xlUp).Row
   End With

   MsgBox (LastRow)
   'first row number where you need to paste values in Sheet1'
   With Worksheets("Sheet1")
      j = .Cells(.Rows.Count, "A").End(xlUp).Row + 1
   End With 

   For i = 1 To LastRow
       With Worksheets("Sheet2")
           If .Cells(i, 1).Value = "X" Then
               .Rows(i).Copy Destination:=Worksheets("Sheet1").Range("A" & j)
               j = j + 1
           End If
       End With
   Next i
End Sub

how to get current month and year

label1.Text = DateTime.Now.Month.ToString();


label2.Text = DateTime.Now.Year.ToString();

Java command not found on Linux

I had these choices:

*  1           /usr/lib/jvm/jre-1.6.0-openjdk.x86_64/bin/java
 + 2           /usr/lib/jvm/jre-1.7.0-openjdk.x86_64/bin/java
   3           /home/ec2-user/local/java/jre1.7.0_25/bin/java

When I chose 3, it didn't work. When I chose 2, it did work.

Oracle PL Sql Developer cannot find my tnsnames.ora file

I had the same problema, but as described in the manual.pdf, you have to:

You are using an Oracle Instant Client but have not set all required environment variables:

  • PATH: Needs to include the Instant Client directory where oci.dll is located
  • TNS_ADMIN: Needs to point to the directory where tnsnames.ora is located.
  • NLS_LANG: Defines the language, territory, and character set for the client.


Creating a blocking Queue<T> in .NET?

That looks very unsafe (very little synchronization); how about something like:

class SizeQueue<T>
    private readonly Queue<T> queue = new Queue<T>();
    private readonly int maxSize;
    public SizeQueue(int maxSize) { this.maxSize = maxSize; }

    public void Enqueue(T item)
        lock (queue)
            while (queue.Count >= maxSize)
            if (queue.Count == 1)
                // wake up any blocked dequeue
    public T Dequeue()
        lock (queue)
            while (queue.Count == 0)
            T item = queue.Dequeue();
            if (queue.Count == maxSize - 1)
                // wake up any blocked enqueue
            return item;


In reality, you'd want a way to close the queue so that readers start exiting cleanly - perhaps something like a bool flag - if set, an empty queue just returns (rather than blocking):

bool closing;
public void Close()
        closing = true;
public bool TryDequeue(out T value)
    lock (queue)
        while (queue.Count == 0)
            if (closing)
                value = default(T);
                return false;
        value = queue.Dequeue();
        if (queue.Count == maxSize - 1)
            // wake up any blocked enqueue
        return true;

Disable and later enable all table indexes in Oracle

You can disable constraints in Oracle but not indexes. There's a command to make an index ununsable but you have to rebuild the index anyway, so I'd probably just write a script to drop and rebuild the indexes. You can use the user_indexes and user_ind_columns to get all the indexes for a schema or use dbms_metadata:

select dbms_metadata.get_ddl('INDEX', u.index_name) from user_indexes u;

How to generate unique IDs for form labels in React?

The id should be placed inside of componentWillMount (update for 2018) constructor, not render. Putting it in render will re-generate new ids unnecessarily.

If you're using underscore or lodash, there is a uniqueId function, so your resulting code should be something like:

constructor(props) {
    super(props); = _.uniqueId("prefix-");

render() { 
  const id =;
  return (
        <input id={id} type="checkbox" />
        <label htmlFor={id}>label</label>

2019 Hooks update:

import React, { useState } from 'react';
import _uniqueId from 'lodash/uniqueId';

const MyComponent = (props) => {
  // id will be set once when the component initially renders, but never again
  // (unless you assigned and called the second argument of the tuple)
  const [id] = useState(_uniqueId('prefix-'));
  return (
      <input id={id} type="checkbox" />
      <label htmlFor={id}>label</label>

SELECT * FROM multiple tables. MySQL

You will have the duplicate values for name and price here. And ids are duplicate in the drinks_photos table.There is no way you can avoid them.Also what exactly you want the output ?

What does "hashable" mean in Python?

In my understanding according to Python glossary, when you create a instance of objects that are hashable, an unchangeable value is also calculated according to the members or values of the instance. For example, that value could then be used as a key in a dict as below:

>>> tuple_a = (1,2,3)
>>> tuple_a.__hash__()
>>> tuple_b = (2,3,4)
>>> tuple_b.__hash__()
>>> tuple_c = (1,2,3)
>>> tuple_c.__hash__()
>>> id(a) == id(c)  # a and c same object?
>>> a.__hash__() == c.__hash__()  # a and c same value?
>>> dict_a = {}
>>> dict_a[tuple_a] = 'hiahia'
>>> dict_a[tuple_c]

we can find that the hash value of tuple_a and tuple_c are the same since they have the same members. When we use tuple_a as the key in dict_a, we can find that the value for dict_a[tuple_c] is the same, which means that, when they are used as the key in a dict, they return the same value because the hash values are the same. For those objects that are not hashable, the method hash is defined as None:

>>> type(dict.__hash__) 
<class 'NoneType'>

I guess this hash value is calculated upon the initialization of the instance, not in a dynamic way, that's why only immutable objects are hashable. Hope this helps.

Convert a space delimited string to list

states = "Alaska Alabama Arkansas American Samoa Arizona California Colorado"
states_list = states.split (' ')

How to get the file extension in PHP?

A better method is using strrpos + substr (faster than explode for that) :

$userfile_name = $_FILES['image']['name'];
$userfile_extn = substr($userfile_name, strrpos($userfile_name, '.')+1);

But, to check the type of a file, using mime_content_type is a better way :

Define a struct inside a class in C++

Something like:

class Tree {

 struct node {
   int data;
   node *llink;
   node *rlink;

PowerShell Remoting giving "Access is Denied" error

Running the command prompt or Powershell ISE as an administrator fixed this for me.

Settings to Windows Firewall to allow Docker for Windows to share drive

I had the same problem and tried all the fixes - and it turned out that more than one was necessary:

  • Add a firewall rule (Norton Security for me)
  • Make the network private
  • Share the drive

I've written a full explanation at

How to find prime numbers between 0 - 100?

Here's my stab at it.

Change the initial i=0 from 0 to whatever you want, and the the second i<100 from 100 to whatever to get primes in a different range.

for(var i=0; i<100; i++){
    var devisableCount = 2;
        for(var x=0; x<=i/2; x++){
            if(i !== 1 && i !== 0 && i !== x){
                if(i%x === 0){
    if(devisableCount === 3){

I tried it with 10000000 - it takes some time but appears to be accurate.

How to drop all tables in a SQL Server database?

Short and sweet:

-- Disable all referential integrity constraints

-- Drop all PKs and FKs
declare @sql nvarchar(max)
SELECT @sql = STUFF((SELECT '; ' + 'ALTER TABLE ' + Table_Name  +'  drop constraint ' + Constraint_Name  from Information_Schema.CONSTRAINT_TABLE_USAGE ORDER BY Constraint_Name FOR XML PATH('')),1,1,'')
EXECUTE (@sql)

-- Drop all tables
EXEC sp_MSforeachtable 'DROP TABLE ?'


All: Evidently this is working as designed. Please see new ref man dated 2019-7-23, Section 6.1.6, Security Issues with LOAD DATA LOCAL.

How to bundle vendor scripts separately and require them as needed with Webpack?

in my webpack.config.js (Version 1,2,3) file, I have

function isExternal(module) {
  var context = module.context;

  if (typeof context !== 'string') {
    return false;

  return context.indexOf('node_modules') !== -1;

in my plugins array

plugins: [
  new CommonsChunkPlugin({
    name: 'vendors',
    minChunks: function(module) {
      return isExternal(module);
  // Other plugins

Now I have a file that only adds 3rd party libs to one file as required.

If you want get more granular where you separate your vendors and entry point files:

plugins: [
  new CommonsChunkPlugin({
    name: 'common',
    minChunks: function(module, count) {
      return !isExternal(module) && count >= 2; // adjustable
  new CommonsChunkPlugin({
    name: 'vendors',
    chunks: ['common'],
    // or if you have an key value object for your entries
    // chunks: Object.keys(entry).concat('common')
    minChunks: function(module) {
      return isExternal(module);

Note that the order of the plugins matters a lot.

Also, this is going to change in version 4. When that's official, I update this answer.

Update: indexOf search change for windows users

Conversion failed when converting the nvarchar value ... to data type int

You are trying to concatenate a string and an integer.
You need to cast @ID as a string.

SET @sql=@sql+' AND Emp_Id_Pk=' + CAST(@ID AS NVARCHAR(10))

null vs empty string in Oracle

In oracle an empty varchar2 and null are treated the same, and your observations show that.

when you write:

select * from table where a = '';

its the same as writing

select * from table where a = null;

and not a is null

which will never equate to true, so never return a row. same on the insert, a NOT NULL means you cant insert a null or an empty string (which is treated as a null)

Difference between Encapsulation and Abstraction

Yes !!!! If I say Encapsulation is a kind of an advanced specific scope abstraction,

How many of you read/upvote my answer. Let's dig in why I am saying like this.

I need to clear two things before my claiming.

One is data hiding and, another one is the abstraction

Data hiding

Most of the time, we will not give direct access to our internal data. Our internal data should not go out directly that is an outside person can't access our internal data directly. It's all about security since we need to protect the internal states of a particular object.


For simplicity, hide the internal implementations is called abstraction. In abstraction, we only focus on the necessary things. Basically, We talk about "What to do" and not "How to do" in abstraction. Security also can be achieved by abstraction since we are not going to highlight "how we are implementing". Maintainability will be increased since we can alter the implementation but it will not affect our end user.

I said, "Encapsulation is a kind of an advanced specific scope abstraction". Why? because we can see encapsulation as data hiding + abstraction

encapsulation = data hiding + abstraction

In encapsulation, we need to hide the data so outside person can not see the data and we need to provide methods that can be used to access the data. These methods may have validations or other features inside those things also hidden to an outside person. So here, we are hiding the implementation of access methods and it is called abstraction.

This is why I said like above encapsulation is a kind of abstraction.

So Where is the difference?

The difference is the abstraction is a general one if we are hiding something from the user for simplicity, maintainability and security and,

encapsulation is a specific one for which is related to internal states security where we are hiding the internal state (data hiding) and we are providing methods to access the data and those methods implementation also hidden from the outside person(abstraction).

Is there a "null coalescing" operator in JavaScript?


JavaScript now supports the nullish coalescing operator (??). It returns its right-hand-side operand when its left-hand-side operand is null or undefined, and otherwise returns its left-hand-side operand.

Please check compatibility before using it.

The JavaScript equivalent of the C# null coalescing operator (??) is using a logical OR (||):

var whatIWant = someString || "Cookies!";

There are cases (clarified below) that the behaviour won't match that of C#, but this is the general, terse way of assigning default/alternative values in JavaScript.


Regardless of the type of the first operand, if casting it to a Boolean results in false, the assignment will use the second operand. Beware of all the cases below:

alert(Boolean(null)); // false
alert(Boolean(undefined)); // false
alert(Boolean(0)); // false
alert(Boolean("")); // false
alert(Boolean("false")); // true -- gotcha! :)

This means:

var whatIWant = null || new ShinyObject(); // is a new shiny object
var whatIWant = undefined || "well defined"; // is "well defined"
var whatIWant = 0 || 42; // is 42
var whatIWant = "" || "a million bucks"; // is "a million bucks"
var whatIWant = "false" || "no way"; // is "false"

Configuring IntelliJ IDEA for unit testing with JUnit

If you already have a test class, but missing the JUnit library dependency, please refer to Configuring Libraries for Unit Testing documentation section. Pressing Alt+Enter on the red code should give you an intention action to add the missing jar.

However, IDEA offers much more. If you don't have a test class yet and want to create one for any of the source classes, see instructions below.

You can use the Create Test intention action by pressing Alt+Enter while standing on the name of your class inside the editor or by using Ctrl+Shift+T keyboard shortcut.

A dialog appears where you select what testing framework to use and press Fix button for the first time to add the required library jars to the module dependencies. You can also select methods to create the test stubs for.

Create Test Intention

Create Test Dialog

You can find more details in the Testing help section of the on-line documentation.

Visualizing branch topology in Git

I have 3 aliases (and 4 alias-aliases for quick usage) that I normally throw in my ~/.gitconfig file:

    lg = lg1
    lg1 = lg1-specific --all
    lg2 = lg2-specific --all
    lg3 = lg3-specific --all

    lg1-specific = log --graph --abbrev-commit --decorate --format=format:'%C(bold blue)%h%C(reset) - %C(bold green)(%ar)%C(reset) %C(white)%s%C(reset) %C(dim white)- %an%C(reset)%C(auto)%d%C(reset)'
    lg2-specific = log --graph --abbrev-commit --decorate --format=format:'%C(bold blue)%h%C(reset) - %C(bold cyan)%aD%C(reset) %C(bold green)(%ar)%C(reset)%C(auto)%d%C(reset)%n''          %C(white)%s%C(reset) %C(dim white)- %an%C(reset)'
    lg3-specific = log --graph --abbrev-commit --decorate --format=format:'%C(bold blue)%h%C(reset) - %C(bold cyan)%aD%C(reset) %C(bold green)(%ar)%C(reset) %C(bold cyan)(committed: %cD)%C(reset) %C(auto)%d%C(reset)%n''          %C(white)%s%C(reset)%n''          %C(dim white)- %an <%ae> %C(reset) %C(dim white)(committer: %cn <%ce>)%C(reset)'

git lg/git lg1 looks like this:

git lg1

git lg2 looks like this:

git lg2

and git lg3 looks like this:

git lg3

It should be noted that this isn't meant as a end-all-be-all solution— it's a template for you to change, add to and fix up to your liking. If you want to use these, my recommendation is to:

  1. Add them to your .gitconfig,
  2. Customize to your liking (different color choices, different line arrangements for the 2- and 3-line versions, etc.),
  3. And then save a copy to a Gist or other code snippet tool so you can copy & paste it into .gitconfigs in the future (or alternatively version control your dotfiles, of course).

Note: Answer copied from and improved upon the answer at since it's far more appropriate here than it was there.  Left the copy on the other question for historical reasons— it's closed now, and the answer's referenced by a bunch of other answers.

Renaming column names of a DataFrame in Spark Scala

def aliasAllColumns(t: DataFrame, p: String = "", s: String = ""): DataFrame =
{ { c => t.col(c).as( p + c + s) } : _* )

In case is isn't obvious, this adds a prefix and a suffix to each of the current column names. This can be useful when you have two tables with one or more columns having the same name, and you wish to join them but still be able to disambiguate the columns in the resultant table. It sure would be nice if there were a similar way to do this in "normal" SQL.

String's Maximum length in Java - calling length() method

apparently it's bound to an int, which is 0x7FFFFFFF (2147483647).

Whats the CSS to make something go to the next line in the page?

There are two options that I can think of, but without more details, I can't be sure which is the better:

#elementId {
    display: block;

This will force the element to a 'new line' if it's not on the same line as a floated element.

#elementId {
     clear: both;

This will force the element to clear the floats, and move to a 'new line.'

In the case of the element being on the same line as another that has position of fixed or absolute nothing will, so far as I know, force a 'new line,' as those elements are removed from the document's normal flow.

Open Jquery modal dialog on click event

If you want to put some page in the dialog then you can use these

function Popup()
 height: 625,
 width: 600,
 close: function(event,ui){




<Div id="pop"  style="display:none;">


Android Color Picker

I ended up here looking for a HSV color picker that offered transparency and copy/paste of the hex value. None of the existing answers met those needs, so here's the library I ended up writing:

HSV-Alpha Color Picker for Android (GitHub).

HSV-Alpha Color Picker Demo (Google Play).

I hope it's useful for somebody else.

Color Picker Dialog

Java, How to add library files in netbeans?

Quick solution in NetBeans 6.8.

In the Projects window right-click on the name of the project that lacks library -> Properties -> The Project Properties window opens. In Categories tree select "Libraries" node -> On the right side of the Project Properties window press button "Add JAR/Folder" -> Select jars you need.

You also can see my short Video How-To.

Java method: Finding object in array list given a known attribute value

I solved this using java 8 lambdas

int dogId = 2;

return> dogId == dog.getId()).collect(Collectors.toList()).get(0);

JQuery .each() backwards

$($("li").get().reverse()).each(function() { /* ... */ });

How To Auto-Format / Indent XML/HTML in Notepad++

To directly answer the OP, take a look at this guy's site: Thomas Hunter Notepad++ Tidy for XML. Simple steps to follow and you get very nice formatting of your XML right inside NPP. So far the only anomaly I've found is with nested self closing elements EG:

<OuterTag>Text for outer element<SelfClosingTag/></OuterTag>

Will be tidied up to:

<OuterTag>Text for outer element

There may be a way to fix this, but for the time being, it's managed to reduce the number of lines in my document by 300k and this particular anomaly can be worked around.

css 100% width div not taking up full width of parent

html, body{ 

This tells the html to be 100% wide. But 100% refers to the whole browser window width, so no more than that.

You may want to set a min width instead.

html, body{ 

So it will be 100% as a minimum, bot more if needed.

Spring's overriding bean

Whether can we declare the same bean id in other xml for other reference e.x.


<bean id="inheritedTestBean"   class="org.springframework.beans.TestBean">
  <property name="name" value="parent"/>
  <property name="age" value="1"/>

Other xml (Document.xml)

<bean id="inheritedTestBean"  class="org.springframework.beans.Document">
  <property name="name" value="document"/>
  <property name="age" value="1"/>

Difference between require, include, require_once and include_once?

  1. Use require function when you need to load any class, function, or dependency.

  2. Use include function when you want to load template-styled file

If you are still confused, just use require_once for all time.

Save PHP variables to a text file

Okay, so I needed a solution to this, and I borrowed heavily from the answers to this question and made a library: (Licensed under the MIT license).

It uses serialize() and unserialize() and writes data to a file. It can read and write multiple objects/variables/whatever to and from the same file.


require 'varDx.php';
$dx = new \varDx\cDX; //create an object
$dx->def('file.dat'); //define data file
$val1 = "this is a string";
$dx->write('data1', $val1); //writes key to file
echo $dx->read('data1'); //returns key value from file

See the github page for more information. It has functions to read, write, check, modify and delete data.

TestNG ERROR Cannot find class in classpath

add to pom:


Batch - If, ElseIf, Else

@echo off
color 0a
set /p language=
if %language% == DE (
    goto LGDE
) else (
    if %language% == EN (
    goto LGEN
    ) else (
    echo N/A


Calculating the position of points in a circle

Using one of the above answers as a base, here's the Java/Android example:

protected void onDraw(Canvas canvas) {

    RectF bounds = new RectF(canvas.getClipBounds());
    float centerX = bounds.centerX();
    float centerY = bounds.centerY();

    float angleDeg = 90f;
    float radius = 20f

    float xPos = radius * (float)Math.cos(Math.toRadians(angleDeg)) + centerX;
    float yPos = radius * (float)Math.sin(Math.toRadians(angleDeg)) + centerY;

    //draw my point at xPos/yPos

How to correct indentation in IntelliJ

Just select the code and

  • on Windows do Ctrl + Alt + L

  • on Linux do Ctrl + Windows Key + Alt + L

  • on Mac do CMD + Option + L

Getting last day of the month in a given string date

The simplest way is to construt a new GregorianCalendar instance, see below:

Calendar cal = new GregorianCalendar(2013, 5, 0);
Date date = cal.getTime();
DateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
System.out.println("Date : " + sdf.format(date));


Date : 2013-05-31


month the value used to set the MONTH calendar field in the calendar. Month value is 0-based e.g. 0 for January.

How can I break up this long line in Python?

For anyone who is also trying to call .format() on a long string, and is unable to use some of the most popular string wrapping techniques without breaking the subsequent .format( call, you can do str.format("", 1, 2) instead of "".format(1, 2). This lets you break the string with whatever technique you like. For example:"Skipping {0} because its thumbnail was already in our system as {1}.".format(line[indexes['url']], video.title))

can be"Skipping {0} because its thumbnail was already"
+ "in our system as {1}"), line[indexes['url']], video.title))

Otherwise, the only possibility is using line ending continuations, which I personally am not a fan of.

gradient descent using python and numpy

Below you can find my implementation of gradient descent for linear regression problem.

At first, you calculate gradient like X.T * (X * w - y) / N and update your current theta with this gradient simultaneously.

  • X: feature matrix
  • y: target values
  • w: weights/values
  • N: size of training set

Here is the python code:

import pandas as pd
import numpy as np
from matplotlib import pyplot as plt
import random

def generateSample(N, variance=100):
    X = np.matrix(range(N)).T + 1
    Y = np.matrix([random.random() * variance + i * 10 + 900 for i in range(len(X))]).T
    return X, Y

def fitModel_gradient(x, y):
    N = len(x)
    w = np.zeros((x.shape[1], 1))
    eta = 0.0001

    maxIteration = 100000
    for i in range(maxIteration):
        error = x * w - y
        gradient = x.T * error / N
        w = w - eta * gradient
    return w

def plotModel(x, y, w):
    plt.plot(x[:,1], y, "x")
    plt.plot(x[:,1], x * w, "r-")

def test(N, variance, modelFunction):
    X, Y = generateSample(N, variance)
    X = np.hstack([np.matrix(np.ones(len(X))).T, X])
    w = modelFunction(X, Y)
    plotModel(X, Y, w)

test(50, 600, fitModel_gradient)
test(50, 1000, fitModel_gradient)
test(100, 200, fitModel_gradient)

test1 test2 test2

How do I get and set Environment variables in C#?

Get and Set


string getEnv = Environment.GetEnvironmentVariable("envVar");


string setEnv = Environment.SetEnvironmentVariable("envvar", varEnv);

How to create dispatch queue in Swift 3

Creating a concurrent queue

let concurrentQueue = DispatchQueue(label: "queuename", attributes: .concurrent)
concurrentQueue.sync {


Create a serial queue

let serialQueue = DispatchQueue(label: "queuename")
serialQueue.sync { 


Get main queue asynchronously

DispatchQueue.main.async {


Get main queue synchronously

DispatchQueue.main.sync {


To get one of the background thread .background).async {


Xcode 8.2 beta 2:

To get one of the background thread .default).async {

} {
    // qos' default value is ´DispatchQoS.QoSClass.default`

If you want to learn about using these queues .See this answer

HTML.ActionLink method

You might want to look at the RouteLink() method.That one lets you specify everything (except the link text and route name) via a dictionary.

Is there a default password to connect to vagrant when using `homestead ssh` for the first time?

On a Windows machine I was able to log to to ssh from git bash with
ssh vagrant@VAGRANT_SERVER_IP without providing a password

Using Bitvise SSH client on window
Server port: 22
Username: vagrant
Password: vagrant