Programs & Examples On #Django dev server

django-dev-server refers to lightweight web server provided by Django for development purposes

What range of values can integer types store in C++

You should look at the specialisations of the numeric_limits<> template for a given type. Its in the header.

How can I use "e" (Euler's number) and power operation in python 2.7

Just saying: numpy has this too. So no need to import math if you already did import numpy as np:

>>> np.exp(1)

Is there a way to disable initial sorting for jquery DataTables?

Try this:

$(document).ready( function () {
    "order": []

this will solve your problem.

BEGIN - END block atomic transactions in PL/SQL

BEGIN-END blocks are the building blocks of PL/SQL, and each PL/SQL unit is contained within at least one such block. Nesting BEGIN-END blocks within PL/SQL blocks is usually done to trap certain exceptions and handle that special exception and then raise unrelated exceptions. Nevertheless, in PL/SQL you (the client) must always issue a commit or rollback for the transaction.

If you wish to have atomic transactions within a PL/SQL containing transaction, you need to declare a PRAGMA AUTONOMOUS_TRANSACTION in the declaration block. This will ensure that any DML within that block can be committed or rolledback independently of the containing transaction.

However, you cannot declare this pragma for nested blocks. You can only declare this for:

  • Top-level (not nested) anonymous PL/SQL blocks
  • List item
  • Local, standalone, and packaged functions and procedures
  • Methods of a SQL object type
  • Database triggers

Reference: Oracle

Adding a slide effect to bootstrap dropdown

If you update to Bootstrap 3 (BS3), they've exposed a lot of Javascript events that are nice to tie your desired functionality into. In BS3, this code will give all of your dropdown menus the animation effect you are looking for:

  // Add slideDown animation to Bootstrap dropdown when expanding.
  $('.dropdown').on('', function() {
    $(this).find('.dropdown-menu').first().stop(true, true).slideDown();

  // Add slideUp animation to Bootstrap dropdown when collapsing.
  $('.dropdown').on('', function() {
    $(this).find('.dropdown-menu').first().stop(true, true).slideUp();

You can read about BS3 events here and specifically about the dropdown events here.

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

The Chromatable jquery plugin allows a fixed header (or top row) with widths that allow percentages--granted, only a percentage of 100%.

I can't think of how you could do this without javascript.

update: new link ->

Passing multiple parameters to function in Python

In case you don't have access to functools.partial, you could use a wrapper function for this, as well.

def target(lock):
    def wrapped_func(items):
        for item in items:
            # Do cool stuff
            if (... some condition here ...):
                # Write to stdout or logfile, etc.
    return wrapped_func

def main():
    iterable = [1, 2, 3, 4, 5]
    pool = multiprocessing.Pool()
    lck = multiprocessing.Lock(), iterable)

This makes target() into a function that accepts a lock (or whatever parameters you want to give), and it will return a function that only takes in an iterable as input, but can still use all your other parameters. That's what is ultimately passed in to, which then should execute with no problems.

Adding +1 to a variable inside a function

Move points into test:

def test():
    points = 0
    addpoint = raw_input ("type ""add"" to add a point")

or use global statement, but it is bad practice. But better way it move points to parameters:

def test(points=0):
    addpoint = raw_input ("type ""add"" to add a point")

How do I toggle an ng-show in AngularJS based on a boolean?

You just need to toggle the value of "isReplyFormOpen" on ng-click event

<a ng-click="isReplyFormOpen = !isReplyFormOpen">Reply</a>
 <div ng-show="isReplyFormOpen" id="replyForm">

Rounding to 2 decimal places in SQL

Try using the COLUMN command with the FORMAT option for that:


Get today date in google appScript

Google Apps Script is JavaScript, the date object is initiated with new Date() and all JavaScript methods apply, see doc here

Postgres: clear entire database before re-creating / re-populating from bash script

To dump:

pg_dump -Fc mydb > db.dump

To restore:

pg_restore --verbose --clean --no-acl --no-owner -h localhost -U myuser -d my_db db/latest.dump

TempData keep() vs peek()

Keep() method marks the specified key in the dictionary for retention

You can use Keep() when prevent/hold the value depends on additional logic.

when you read TempData one’s and want to hold for another request then use keep method, so TempData can available for next request as above example.

What’s the best way to check if a file exists in C++? (cross platform)

I am a happy boost user and would certainly use Andreas' solution. But if you didn't have access to the boost libs you can use the stream library:

ifstream file(argv[1]);
if (!file)
    // Can't open file

It's not quite as nice as boost::filesystem::exists since the file will actually be opened...but then that's usually the next thing you want to do anyway.

Remove a folder from git tracking

I came across this question while Googling for "git remove folder from tracking". The OP's question lead me to the answer. I am summarizing it here for future generations.


How do I remove a folder from my git repository without deleting it from my local machine (i.e., development environment)?


Step 1. Add the folder path to your repo's root .gitignore file.


Step 2. Remove the folder from your local git tracking, but keep it on your disk.

git rm -r --cached path_to_your_folder/

Step 3. Push your changes to your git repo.

The folder will be considered "deleted" from Git's point of view (i.e. they are in past history, but not in the latest commit, and people pulling from this repo will get the files removed from their trees), but stay on your working directory because you've used --cached.

How do I pick 2 random items from a Python set?

Use the random module:

import random
random.sample(set([1, 2, 3, 4, 5, 6]), 2)

This samples the two values without replacement (so the two values are different).

Specify the date format in XMLGregorianCalendar

Much simpler using only SimpleDateFormat, without passing all the parameters individual:

    String FORMATER = "yyyy-MM-dd'T'HH:mm:ss'Z'";

    DateFormat format = new SimpleDateFormat(FORMATER);

    Date date = new Date();
    XMLGregorianCalendar gDateFormatted =

Full example here.

Note: This is working only to remove the last 2 fields: milliseconds and timezone or to remove the entire time component using formatter yyyy-MM-dd.

Importing images from a directory (Python) to list or dictionary

I'd start by using glob:

from PIL import Image
import glob
image_list = []
for filename in glob.glob('yourpath/*.gif'): #assuming gif

then do what you need to do with your list of images (image_list).

error, string or binary data would be truncated when trying to insert

on sql server you can use SET ANSI_WARNINGS OFF like this:

        using (SqlConnection conn = new SqlConnection("Data Source=XRAYGOAT\\SQLEXPRESS;Initial Catalog='Healthy Care';Integrated Security=True"))

            using (var trans = conn.BeginTransaction())
                    using cmd = new SqlCommand("", conn, trans))

                    cmd.CommandText = "SET ANSI_WARNINGS OFF";

                    cmd.CommandText = "YOUR INSERT HERE";


                    cmd.CommandText = "SET ANSI_WARNINGS ON";

                catch (Exception)





C++ vector's insert & push_back difference

The functions have different purposes. vector::insert allows you to insert an object at a specified position in the vector, whereas vector::push_back will just stick the object on the end. See the following example:

using namespace std;
vector<int> v = {1, 3, 4};
v.insert(next(begin(v)), 2);
// v now contains {1, 2, 3, 4, 5}

You can use insert to perform the same job as push_back with v.insert(v.end(), value).

Android setOnClickListener method - How does it work?

It works by same principle of anonymous inner class where we can instantiate an interface without actually defining a class :


SQL how to make null values come last when sorting ascending

In Oracle, you can use NULLS FIRST or NULLS LAST: specifies that NULL values should be returned before / after non-NULL values:

ORDER BY { column-Name | [ ASC | DESC ] | [ NULLS FIRST | NULLS LAST ] }

For example:



Some projects cannot be imported because they already exist in the workspace error in Eclipse

Check if you have configured Eclipse to show ALL the working set. I once encountered exactly the same problem and it turned out I accidentally imported the project into the Other Projects working set. And my Eclipse configuration didn't show that working set in the package explorer, which lead me to believe that the project was not imported yet.

Updated for @Mawg:

First, click the Select Working Set...:

enter image description here

Then, choose No Working Sets:

enter image description here

This will effectively disable the working set and show all projects.

Make elasticsearch only return certain fields?

For the ES versions 5.X and above you can a ES query something like this:

    GET /.../...
      "_source": {
        "includes": [ "FIELD1", "FIELD2", "FIELD3" ... " ]

How to compare two vectors for equality element by element in C++?

C++11 standard on == for std::vector

Others have mentioned that operator== does compare vector contents and works, but here is a quote from the C++11 N3337 standard draft which I believe implies that.

We first look at Chapter 23.2.1 "General container requirements", which documents things that must be valid for all containers, including therefore std::vector.

That section Table 96 "Container requirements" which contains an entry:

Expression   Operational semantics
===========  ======================
a == b       distance(a.begin(), a.end()) == distance(b.begin(), b.end()) &&
             equal(a.begin(), a.end(), b.begin())

The distance part of the semantics means that the size of both containers are the same, but stated in a generalized iterator friendly way for non random access addressable containers. distance() is defined at 24.4.4 "Iterator operations".

Then the key question is what does equal() mean. At the end of the table we see:

Notes: the algorithm equal() is defined in Clause 25.

and in section 25.2.11 "Equal" we find its definition:

template<class InputIterator1, class InputIterator2>
bool equal(InputIterator1 first1, InputIterator1 last1,
           InputIterator2 first2);

template<class InputIterator1, class InputIterator2,
class BinaryPredicate>
bool equal(InputIterator1 first1, InputIterator1 last1,
           InputIterator2 first2, BinaryPredicate pred);

1 Returns: true if for every iterator i in the range [first1,last1) the following corresponding conditions hold: *i == *(first2 + (i - first1)), pred(*i, *(first2 + (i - first1))) != false. Otherwise, returns false.

In our case, we care about the overloaded version without BinaryPredicate version, which corresponds to the first pseudo code definition *i == *(first2 + (i - first1)), which we see is just an iterator-friendly definition of "all iterated items are the same".

Similar questions for other containers:

text-align:center won't work with form <label> tag (?)

This is because label is an inline element, and is therefore only as big as the text it contains.

The possible is to display your label as a block element like this:

#formItem label {
    display: block;
    text-align: center;
    line-height: 150%;
    font-size: .85em;

However, if you want to use the label on the same line with other elements, you either need to set display: inline-block; and give it an explicit width (which doesn't work on most browsers), or you need to wrap it inside a div and do the alignment in the div.

How to handle the `onKeyPress` event in ReactJS?

React is not passing you the kind of events you might think. Rather, it is passing synthetic events.

In a brief test, event.keyCode == 0 is always true. What you want is event.charCode

Ruby: What is the easiest way to remove the first element from an array?

You can use:

arr - [arr[0]]


arr - [arr.shift]

or simply


Linux: copy and create destination dir if it does not exist

If both of the following are true:

  1. You are using the GNU version of cp (and not, for instance, the Mac version), and
  2. You are copying from some existing directory structure and you just need it recreated

then you can do this with the --parents flag of cp. From the info page (viewable at or with info cp or man cp):

     Form the name of each destination file by appending to the target
     directory a slash and the specified name of the source file.  The
     last argument given to `cp' must be the name of an existing
     directory.  For example, the command:

          cp --parents a/b/c existing_dir

     copies the file `a/b/c' to `existing_dir/a/b/c', creating any
     missing intermediate directories.


/tmp $ mkdir foo
/tmp $ mkdir foo/foo
/tmp $ touch foo/foo/foo.txt
/tmp $ mkdir bar
/tmp $ cp --parents foo/foo/foo.txt bar
/tmp $ ls bar/foo/foo

Set type for function parameters?

Check out the new Flow library from Facebook, "a static type checker, designed to find type errors in JavaScript programs"


/* @flow */
function foo(x: string, y: number): string {
  return x.length * y;
foo('Hello', 42);

Type checking:

$> flow
hello.js:3:10,21: number
This type is incompatible with
  hello.js:2:37,42: string

And here is how to run it.

Moving average or running mean

For a ready-to-use solution, see It provides running average with the flat window type. Note that this is a bit more sophisticated than the simple do-it-yourself convolve-method, since it tries to handle the problems at the beginning and the end of the data by reflecting it (which may or may not work in your case...).

To start with, you could try:

a = np.random.random(100)
b = smooth(a, window='flat')

A JNI error has occurred, please check your installation and try again in Eclipse x86 Windows 8.1

edit the ".classpath" and include below tag

<classpathentry kind="con" path="org.testng.TESTNG_CONTAINER"/>

this could solve your problem.

How to prune local tracking branches that do not exist on remote anymore

Following is an adaptation of @wisbucky's answer for Windows users:

for /f "tokens=1" %i in ('git branch -vv ^| findstr ": gone]"') DO git branch %i -d

I use posh-git and unfortunately PS doesn't like the naked for, so I created a plain 'ol command script named PruneOrphanBranches.cmd:

for /f "tokens=1" %%i in ('git branch -vv ^| findstr ": gone]"') DO CALL :ProcessBranch %%i %1


IF /I "%2%"=="-d" (
    git branch %1 %2
) ELSE (
    CALL :OutputMessage %1

ECHO Will delete branch [%1] 


Call it with no parameters to see a list, and then call it with "-d" to perform the actual deletion or "-D" for any branches that are not fully merged but which you want to delete anyway.

The requested URL /about was not found on this server

I am working on MacOS, following operation solved my problem:

I copied from :

cd /etc/apache2

Give write permission the config file to root: sudo chmod u+w httpd.conf sudo vim httpd.conf

Find #LoadModule php5_module libexec/apache2/

and remove the leading #

Find #LoadModule rewrite_module libexec/apache2/

and remove the leading #

Find AllowOverride None within the section and change to AllowOverride All so that .htaccess files will work.

Change permissions back: sudo chmod u-w httpd.conf

Restart Apache by running following in terminal:

sudo apachectl restart

Python element-wise tuple operations like sum

import operator
tuple(map(operator.add, a, b))

Convert MySQL to SQlite

There is a script on GitHub

As described in the header, the script can be used like this:

./ myDbase | sqlite3 database.sqlite


Apply function to all elements of collection through LINQ

Or you can hack it up.

Items.All(p => { p.IsAwesome = true; return true; });

How do I get git to default to ssh and not https for new repositories

Set up a repository's origin branch to be SSH

The GitHub repository setup page is just a suggested list of commands (and GitHub now suggests using the HTTPS protocol). Unless you have administrative access to GitHub's site, I don't know of any way to change their suggested commands.

If you'd rather use the SSH protocol, simply add a remote branch like so (i.e. use this command in place of GitHub's suggested command). To modify an existing branch, see the next section.

$ git remote add origin [email protected]:nikhilbhardwaj/abc.git

Modify a pre-existing repository

As you already know, to switch a pre-existing repository to use SSH instead of HTTPS, you can change the remote url within your .git/config file.

[remote "origin"]
    fetch = +refs/heads/*:refs/remotes/origin/*
    -url =
    +url = [email protected]:nikhilbhardwaj/abc.git

A shortcut is to use the set-url command:

$ git remote set-url origin [email protected]:nikhilbhardwaj/abc.git

More information about the SSH-HTTPS switch

Squaring all elements in a list

Use numpy.

import numpy as np
b = list(np.array(a)**2)

T-SQL Substring - Last 3 Characters

You can use either way:

SELECT RIGHT(RTRIM(columnName), 3)


SELECT SUBSTRING(columnName, LEN(columnName)-2, 3)

How to get the focused element with jQuery?

// Get the focused element:
var $focused = $(':focus');

// No jQuery:
var focused = document.activeElement;

// Does the element have focus:
var hasFocus = $('foo').is(':focus');

// No jQuery:
elem === elem.ownerDocument.activeElement;

Which one should you use? quoting the jQuery docs:

As with other pseudo-class selectors (those that begin with a ":"), it is recommended to precede :focus with a tag name or some other selector; otherwise, the universal selector ("*") is implied. In other words, the bare $(':focus') is equivalent to $('*:focus'). If you are looking for the currently focused element, $( document.activeElement ) will retrieve it without having to search the whole DOM tree.

The answer is:


And if you want a jQuery object wrapping the element:


Jackson enum Serializing and DeSerializer

In my case, this is what resolved:

import com.fasterxml.jackson.annotation.JsonCreator;
import com.fasterxml.jackson.annotation.JsonFormat;
import com.fasterxml.jackson.annotation.JsonProperty;

@JsonFormat(shape = JsonFormat.Shape.OBJECT)
public enum PeriodEnum {


    private final int id;

    PeriodEnum(int id) { = id;

    public int getId() {
        return id;

    public String getName() {

    public static PeriodEnum fromJson(@JsonProperty("name") String name) {
        return valueOf(name);

Serializes and deserializes the following json:

  "id": 2,
  "name": "WEEKLY"

I hope it helps!

Prevent row names to be written to file when using write.csv

write.csv(t, "t.csv", row.names=FALSE)

From ?write.csv:

row.names: either a logical value indicating whether the row names of
          ‘x’ are to be written along with ‘x’, or a character vector
          of row names to be written.

overlay opaque div over youtube iframe

Information from the Official Adobe site about this issue

The issue is when you embed a youtube link:

in an iFrame, the default wmode is windowed which essentially gives it a z-index greater then everything else and it will overlay over anything.

Try appending this GET parameter to your URL:


like so:

Make sure its the first parameter in the URL. Other parameters must go after

In the iframe tag:


<iframe class="youtube-player" type="text/html" width="520" height="330" src="" frameborder="0"></iframe>

Eclipse No tests found using JUnit 5 caused by NoClassDefFoundError for LauncherFactory

Using STS 3.9.1 I got the same problem. However, currently I do not require any new JUnit5 features, so I tried to force using an older version. If using maven, you can add following dependencies to your pom.xml:




This did the trick for me (at least as long as I do not need JUnit5 explicitly).

How can I check if a key exists in a dictionary?

If you want to retrieve the key's value if it exists, you can also use

    value = a[key]
except KeyError:
    # Key is not present

If you want to retrieve a default value when the key does not exist, use value = a.get(key, default_value). If you want to set the default value at the same time in case the key does not exist, use value = a.setdefault(key, default_value).

Grouping into interval of 5 minutes within a time range

How about this one:

    from_unixtime(unix_timestamp(timestamp) - unix_timestamp(timestamp) mod 300) as ts,  
from group_interval 
group by ts 
order by ts

Maven Installation OSX Error Unsupported major.minor version 51.0

The problem is because you haven't set JAVA_HOME in Mac properly. In order to do that, you should do set it like this:

export JAVA_HOME=/Library/Java/JavaVirtualMachines/jdk1.8.0_40.jdk/Contents/Home

In my case my JDK installation is jdk1.8.0_40, make sure you type yours.

Then you can use maven commands.


How to avoid mysql 'Deadlock found when trying to get lock; try restarting transaction'

You might try having that delete job operate by first inserting the key of each row to be deleted into a temp table like this pseudocode

create temporary table deletetemp (userid int);

insert into deletetemp (userid)
  select userid from onlineusers where datetime <= now - interval 900 second;

delete from onlineusers where userid in (select userid from deletetemp);

Breaking it up like this is less efficient but it avoids the need to hold a key-range lock during the delete.

Also, modify your select queries to add a where clause excluding rows older than 900 seconds. This avoids the dependency on the cron job and allows you to reschedule it to run less often.

Theory about the deadlocks: I don't have a lot of background in MySQL but here goes... The delete is going to hold a key-range lock for datetime, to prevent rows matching its where clause from being added in the middle of the transaction, and as it finds rows to delete it will attempt to acquire a lock on each page it is modifying. The insert is going to acquire a lock on the page it is inserting into, and then attempt to acquire the key lock. Normally the insert will wait patiently for that key lock to open up but this will deadlock if the delete tries to lock the same page the insert is using because thedelete needs that page lock and the insert needs that key lock. This doesn't seem right for inserts though, the delete and insert are using datetime ranges that don't overlap so maybe something else is going on.

Use String.split() with multiple delimiters

The string you give split is the string form of a regular expression, so:

private void getId(String pdfName){
    String[]tokens = pdfName.split("[\\-.]");

That means to split on any character in the [] (we have to escape - with a backslash because it's special inside []; and of course we have to escape the backslash because this is a string). (Conversely, . is normally special but isn't special inside [].)

Pure CSS animation visibility with delay

Unfortunately you can't animate the display property. For a full list of what you can animate, try this CSS animation list by w3 Schools.

If you want to retain it's visual position on the page, you should try animating either it's height (which will still affect the position of other elements), or opacity (how transparent it is). You could even try animating the z-index, which is the position on the z axis (depth), by putting an element over the top of it, and then rearranging what's on top. However, I'd suggest using opacity, as it retains the vertical space where the element is.

I've updated the fiddle to show an example.

Good luck!

loading json data from local file into React JS

My JSON file name: terrifcalculatordata.json

      "id": 1,
      "name": "Vigo",
      "picture": "./static/images/vigo.png",
      "charges": "PKR 100 per excess km"
      "id": 2,
      "name": "Mercedes",
      "picture": "./static/images/Marcedes.jpg",
      "charges": "PKR 200 per excess km"
        "id": 3,
        "name": "Lexus",
        "picture": "./static/images/Lexus.jpg",
        "charges": "PKR 150 per excess km"

First , import on top:

import calculatorData from "../static/data/terrifcalculatordata.json";

then after return:

  {, index) => {
        return (
            <div key={index}>

How do I work with a git repository within another repository?

If I understand your problem well you want the following things:

  1. Have your media files stored in one single git repository, which is used by many projects
  2. If you modify a media file in any of the projects in your local machine, it should immediately appear in every other project (so you don't want to commit+push+pull all the time)

Unfortunately there is no ultimate solution for what you want, but there are some things by which you can make your life easier.

First you should decide one important thing: do you want to store for every version in your project repository a reference to the version of the media files? So for example if you have a project called, do you need know which style.css it used 2 weeks ago, or the latest is always (or mostly) the best?

If you don't need to know that, the solution is easy:

  1. create a repository for the media files and one for each project
  2. create a symbolic link in your projects which point to the locally cloned media repository. You can either create a relative symbolic link (e.g. ../media) and assume that everybody will checkout the project so that the media directory is in the same place, or write the name of the symbolic link into .gitignore, and everybody can decide where he/she puts the media files.

In most of the cases, however, you want to know this versioning information. In this case you have two choices:

  1. Store every project in one big repository. The advantage of this solution is that you will have only 1 copy of the media repository. The big disadvantage is that it is much harder to switch between project versions (if you checkout to a different version you will always modify ALL projects)

  2. Use submodules (as explained in answer 1). This way you will store the media files in one repository, and the projects will contain only a reference to a specific media repo version. But this way you will normally have many local copies of the media repository, and you cannot easily modify a media file in all projects.

If I were you I would probably choose the first or third solution (symbolic links or submodules). If you choose to use submodules you can still do a lot of things to make your life easier:

  1. Before committing you can rename the submodule directory and put a symlink to a common media directory. When you're ready to commit, you can remove the symlink and remove the submodule back, and then commit.

  2. You can add one of your copy of the media repository as a remote repository to all of your projects.

You can add local directories as a remote this way:

cd /my/project2/media
git remote add project1 /my/project1/media

If you modify a file in /my/project1/media, you can commit it and pull it from /my/project2/media without pushing it to a remote server:

cd /my/project1/media
git commit -a -m "message"
cd /my/project2/media
git pull project1 master

You are free to remove these commits later (with git reset) because you haven't shared them with other users.

Controller 'ngModel', required by directive '...', can't be found

You can also remove the line

  require: 'ngModel',

if you don't need ngModel in this directive. Removing ngModel will allow you to make a directive without thatngModel error.

What is the format for the PostgreSQL connection string / URL?


Changing SQL Server collation to case insensitive from case sensitive?

You can do that but the changes will affect for new data that is inserted on the database. On the long run follow as suggested above.

Also there are certain tricks you can override the collation, such as parameters for stored procedures or functions, alias data types, and variables are assigned the default collation of the database. To change the collation of an alias type, you must drop the alias and re-create it.

You can override the default collation of a literal string by using the COLLATE clause. If you do not specify a collation, the literal is assigned the database default collation. You can use DATABASEPROPERTYEX to find the current collation of the database.

You can override the server, database, or column collation by specifying a collation in the ORDER BY clause of a SELECT statement.

Why are my CSS3 media queries not working on mobile devices?

I was having this same problem and it turns out my media queries were in the wrong order. They should be defined from widest to smallest in the CSS

Truncate a string straight JavaScript

Thought I would give Sugar.js a mention. It has a truncate method that is pretty smart.

From the documentation:

Truncates a string. Unless split is true, truncate will not split words up, and instead discard the word where the truncation occurred.


'just sittin on the dock of the bay'.truncate(20)


just sitting on...

Moving items around in an ArrayList

Moving element with respect to each other is something I needed a lot in a project of mine. So I wrote a small util class that moves an element in an list to a position relative to another element. Feel free to use (and improve upon ;))

import java.util.List;

public class ListMoveUtil
    enum Position

     * Moves element `elementToMove` to be just before or just after `targetElement`.
     * @param list
     * @param elementToMove
     * @param targetElement
     * @param pos
    public static <T> void moveElementTo( List<T> list, T elementToMove, T targetElement, Position pos )
        if ( elementToMove.equals( targetElement ) )
        int srcIndex = list.indexOf( elementToMove );
        int targetIndex = list.indexOf( targetElement );
        if ( srcIndex < 0 )
            throw new IllegalArgumentException( "Element: " + elementToMove + " not in the list!" );
        if ( targetIndex < 0 )
            throw new IllegalArgumentException( "Element: " + targetElement + " not in the list!" );
        list.remove( elementToMove );

        // if the element to move is after the targetelement in the list, just remove it
        // else the element to move is before the targetelement. When we removed it, the targetindex should be decreased by one
        if ( srcIndex < targetIndex )
            targetIndex -= 1;
        switch ( pos )
            case AFTER:
                list.add( targetIndex + 1, elementToMove );
            case BEFORE:
                list.add( targetIndex, elementToMove );

IIS w3svc error

Make sure these 2 services running and their startup type is automatic.If they disabled and not running right click on them and go to properties and change from there.

  1. Windows process activation service
  2. Worldwide web publishing service.

How to open a web page from my application?

I've been using this line to launch the default browser:


"VT-x is not available" when I start my Virtual machine

VT-x can normally be disabled/enabled in your BIOS.

When your PC is just starting up you should press DEL (or something) to get to the BIOS settings. There you'll find an option to enable VT-technology (or something).

How to get folder directory from HTML input type "file" or any other way?

Eventhough it is an old question, this may help someone.

We can choose multiple files while browsing for a file using "multiple"

<input type="file" name="datafile" size="40"  multiple> 

MySQL Multiple Joins in one query?

Just add another join:

SELECT dashboard_data.headline,
FROM dashboard_data 
    INNER JOIN dashboard_messages
            ON dashboard_message_id = 
    INNER JOIN images
            ON dashboard_messages.image_id = images.image_id

Home does not contain an export named Home

This is a case where you mixed up default exports and named exports.

When dealing with the named exports, if you try to import them you should use curly braces as below,

import { Home } from './layouts/Home'; // if the Home is a named export

In your case the Home was exported as a default one. This is the one that will get imported from the module, when you don’t specify a certain name of a certain piece of code. When you import, and omit the curly braces, it will look for the default export in the module you’re importing from. So your import should be,

import Home from './layouts/Home'; // if the Home is a default export

Some references to look :

Why would someone use WHERE 1=1 AND <conditions> in a SQL clause?

Seems like a lazy way to always know that your WHERE clause is already defined and allow you to keep adding conditions without having to check if it is the first one.

Can a local variable's memory be accessed outside its scope?

Did you compile your program with the optimiser enabled? The foo() function is quite simple and might have been inlined or replaced in the resulting code.

But I agree with Mark B that the resulting behavior is undefined.

Class has no member named

The reason that the error is occuring is because all the files are not being recognized as being in the same project directory. The easiest way to fix this is to simply create a new project.

File -> Project -> Console application -> Next -> select C or C++ -> Name the project and select the folder to create the project in -> then click finish.

Then to create the class and header files by clicking New -> Class. Give the class a name and uncheck "Use relative path." Make sure you are creating the class and header file in the same project folder.

After these steps, the left side of the IDE will display the Sources and Headers folders, with main.cpp, theclassname.cpp, and theclassname.h all conviently arranged.

How to merge two PDF files into one in Java?

Why not use the PDFMergerUtility of pdfbox?

PDFMergerUtility ut = new PDFMergerUtility();

Selecting multiple columns/fields in MySQL subquery

Yes, you can do this. The knack you need is the concept that there are two ways of getting tables out of the table server. One way is ..


The other way is

FROM (SELECT col as name1, col2 as name2 FROM ...) B

Notice that the select clause and the parentheses around it are a table, a virtual table.

So, using your second code example (I am guessing at the columns you are hoping to retrieve here):

SELECT a.attr,, b.trans, b.lang
FROM attribute a
 SELECT AS id, at.translation AS trans, at.language AS lang, a.attribute
 FROM attributeTranslation at
) b ON ( = b.attribute AND b.lang = 1)

Notice that your real table attribute is the first table in this join, and that this virtual table I've called b is the second table.

This technique comes in especially handy when the virtual table is a summary table of some kind. e.g.

SELECT a.attr,, b.trans, b.lang, c.langcount
FROM attribute a
 SELECT AS id, at.translation AS trans, at.language AS lang, at.attribute
 FROM attributeTranslation at
) b ON ( = b.attribute AND b.lang = 1)
 SELECT count(*) AS langcount,  at.attribute
 FROM attributeTranslation at
 GROUP BY at.attribute
) c ON ( = c.attribute)

See how that goes? You've generated a virtual table c containing two columns, joined it to the other two, used one of the columns for the ON clause, and returned the other as a column in your result set.

How to send email to multiple recipients with addresses stored in Excel?

ToAddress = "[email protected]"
ToAddress1 = "[email protected]"
ToAddress2 = "[email protected]"
MessageSubject = "It works!."
Set ol = CreateObject("Outlook.Application")
Set newMail = ol.CreateItem(olMailItem)
newMail.Subject = MessageSubject

How do I create a GUI for a windows application using C++?

I strongly prefer simply using Microsoft Visual Studio and writing a native Win32 app.

For a GUI as simple as the one that you describe, you could simply create a Dialog Box and use it as your main application window. The default application created by the Win32 Project wizard in Visual Studio actually pops a window, so you can replace that window with your Dialog Box and replace the WndProc with a similar (but simpler) DialogProc.

The question, then, is one of tools and cost. The Express Edition of Visual C++ does everything you want except actually create the Dialog Template resource. For this, you could either code it in the RC file by hand or in memory by hand. Related SO question: Windows API Dialogs without using resource files.

Or you could try one of the free resource editors that others have recommended.

Finally, the Visual Studio 2008 Standard Edition is a costlier option but gives you an integrated resource editor.

ImportError: No module named PIL

I recently installed Leap. I Tried openshot and it didn't start. So came here and found a suggestion to start from the Terminal to see if there were any error.

The error I had was error missing mlt. So I installed the python-mlt module from Yast and imported it, tried to start but next openshot said missing pil.

I Followed the Pillow suggestion to install because Yast couldn't find any pil and imported pil. That went ok but did not start and showed Error missing goocanvas.

The I installed goocanvas with Yast, imported it in python, and Openshot fired up !!

With a lot of errors in the terminal like missing Vimeoclient and lots of attributeerrors. Well, will see if it is of any influence working with it.

"Use of undeclared type" in Swift, even though type is internal, and exists in same module

In case anyone encounters a similar problem but the Compile Sources fix does not solve the problem, restarting Xcode may (it worked for me). My version of Xcode is Version 6.1 (6A1052d).

How can I make sticky headers in RecyclerView? (Without external lib)

Another solution, based on scroll listener. Initial conditions are the same as in Sevastyan answer

RecyclerView recyclerView;
TextView tvTitle; //sticky header view

//... onCreate, initialize, etc...

public void bindList(List<Item> items) { //All data in adapter. Item - just interface for different item types
    adapter = new YourAdapter(items);
    StickyHeaderViewManager<HeaderItem> stickyHeaderViewManager = new StickyHeaderViewManager<>(
            HeaderItem.class, //HeaderItem - subclass of Item, used to detect headers in list
            data -> { // bind function for sticky header view

Layout for ViewHolder and sticky header.


<TextView xmlns:android=""

Layout for RecyclerView



    <!--it can be any view, but order important, draw over recyclerView-->


Class for HeaderItem.

public class HeaderItem implements Item {

    private String title;

    public HeaderItem(String title) {
        this.title = title;

    public String getTitle() {
        return title;


It's all use. The implementation of the adapter, ViewHolder and other things, is not interesting for us.

public class StickyHeaderViewManager<T> {

    private View headerView;

    private RecyclerView recyclerView;

    private StickyHeaderViewWrapper<T> viewWrapper;

    private Class<T> headerDataClass;

    private List<?> items;

    public StickyHeaderViewManager(@Nonnull View headerView,
                                   @Nonnull RecyclerView recyclerView,
                                   @Nonnull Class<T> headerDataClass,
                                   @Nonnull StickyHeaderViewWrapper<T> viewWrapper) {
        this.headerView = headerView;
        this.viewWrapper = viewWrapper;
        this.recyclerView = recyclerView;
        this.headerDataClass = headerDataClass;

    public void attach(@Nonnull List<?> items) {
        this.items = items;
        if (ViewCompat.isLaidOut(headerView)) {
        } else {
   -> bindHeader(recyclerView));

        recyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {

            public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
                super.onScrolled(recyclerView, dx, dy);

    private void bindHeader(RecyclerView recyclerView) {
        if (items.isEmpty()) {
        } else {

        View topView = recyclerView.getChildAt(0);
        if (topView == null) {
        int topPosition = recyclerView.getChildAdapterPosition(topView);
        if (!isValidPosition(topPosition)) {
        if (topPosition == 0 && topView.getTop() == recyclerView.getTop()) {
        } else {

        T stickyItem;
        Object firstItem = items.get(topPosition);
        if (headerDataClass.isInstance(firstItem)) {
            stickyItem = headerDataClass.cast(firstItem);
        } else {
            stickyItem = findNearestHeader(topPosition);
            int secondPosition = topPosition + 1;
            if (isValidPosition(secondPosition)) {
                Object secondItem = items.get(secondPosition);
                if (headerDataClass.isInstance(secondItem)) {
                    View secondView = recyclerView.getChildAt(1);
                    if (secondView != null) {
                } else {

        if (stickyItem != null) {

    private void moveViewFor(View secondView) {
        if (secondView.getTop() <= headerView.getBottom()) {
            headerView.setTranslationY(secondView.getTop() - headerView.getHeight());
        } else {

    private T findNearestHeader(int position) {
        for (int i = position; position >= 0; i--) {
            Object item = items.get(i);
            if (headerDataClass.isInstance(item)) {
                return headerDataClass.cast(item);
        return null;

    private boolean isValidPosition(int position) {
        return !(position == RecyclerView.NO_POSITION || position >= items.size());

Interface for bind header view.

public interface StickyHeaderViewWrapper<T> {

    void bindView(T data);

Android Gallery on Android 4.4 (KitKat) returns different URI for Intent.ACTION_GET_CONTENT


How to get an actual file path from a URI


To my knowledge, we don't need to get the file path from a URI because for most of the cases we can directly use the URI to get our work done (like 1. getting bitmap 2. Sending a file to the server, etc.)

1. Sending to the server

We can directly send the file to the server using just the URI.

Using the URI we can get InputStream, which we can directly send to the server using MultiPartEntity.


 * Used to form Multi Entity for a URI (URI pointing to some file, which we got from other application).
 * @param uri     URI.
 * @param context Context.
 * @return Multi Part Entity.
public MultipartEntity formMultiPartEntityForUri(final Uri uri, final Context context) {
    MultipartEntity multipartEntity = new MultipartEntity(HttpMultipartMode.BROWSER_COMPATIBLE, null, Charset.forName("UTF-8"));
    try {
        InputStream inputStream = mContext.getContentResolver().openInputStream(uri);
        if (inputStream != null) {
            ContentBody contentBody = new InputStreamBody(inputStream, getFileNameFromUri(uri, context));
            multipartEntity.addPart("[YOUR_KEY]", contentBody);
    catch (Exception exp) {
        Log.e("TAG", exp.getMessage());
    return multipartEntity;

 * Used to get a file name from a URI.
 * @param uri     URI.
 * @param context Context.
 * @return File name from URI.
public String getFileNameFromUri(final Uri uri, final Context context) {

    String fileName = null;
    if (uri != null) {
        // Get file name.
        // File Scheme.
        if (ContentResolver.SCHEME_FILE.equals(uri.getScheme())) {
            File file = new File(uri.getPath());
            fileName = file.getName();
        // Content Scheme.
        else if (ContentResolver.SCHEME_CONTENT.equals(uri.getScheme())) {
            Cursor returnCursor =
                    context.getContentResolver().query(uri, null, null, null, null);
            if (returnCursor != null && returnCursor.moveToFirst()) {
                int nameIndex = returnCursor.getColumnIndex(OpenableColumns.DISPLAY_NAME);
                fileName = returnCursor.getString(nameIndex);
    return fileName;

2. Getting a BitMap from a URI

If the URI is pointing to image then we will get bitmap, else null:

 * Used to create bitmap for the given URI.
 * <p>
 * 1. Convert the given URI to bitmap.
 * 2. Calculate ratio (depending on bitmap size) on how much we need to subSample the original bitmap.
 * 3. Create bitmap bitmap depending on the ration from URI.
 * 4. Reference -
 * @param context       Context.
 * @param uri           URI to the file.
 * @param bitmapSize Bitmap size required in PX.
 * @return Bitmap bitmap created for the given URI.
 * @throws IOException
public static Bitmap createBitmapFromUri(final Context context, Uri uri, final int bitmapSize) throws IOException {

    // 1. Convert the given URI to bitmap.
    InputStream input = context.getContentResolver().openInputStream(uri);
    BitmapFactory.Options onlyBoundsOptions = new BitmapFactory.Options();
    onlyBoundsOptions.inJustDecodeBounds = true;
    onlyBoundsOptions.inDither = true;//optional
    onlyBoundsOptions.inPreferredConfig = Bitmap.Config.ARGB_8888;//optional
    BitmapFactory.decodeStream(input, null, onlyBoundsOptions);
    if ((onlyBoundsOptions.outWidth == -1) || (onlyBoundsOptions.outHeight == -1)) {
        return null;

    // 2. Calculate ratio.
    int originalSize = (onlyBoundsOptions.outHeight > onlyBoundsOptions.outWidth) ? onlyBoundsOptions.outHeight : onlyBoundsOptions.outWidth;
    double ratio = (originalSize > bitmapSize) ? (originalSize / bitmapSize) : 1.0;

    // 3. Create bitmap.
    BitmapFactory.Options bitmapOptions = new BitmapFactory.Options();
    bitmapOptions.inSampleSize = getPowerOfTwoForSampleRatio(ratio);
    bitmapOptions.inDither = true;//optional
    bitmapOptions.inPreferredConfig = Bitmap.Config.ARGB_8888;//optional
    input = context.getContentResolver().openInputStream(uri);
    Bitmap bitmap = BitmapFactory.decodeStream(input, null, bitmapOptions);

    return bitmap;

 * For Bitmap option inSampleSize - We need to give value in power of two.
 * @param ratio Ratio to be rounded of to power of two.
 * @return Ratio rounded of to nearest power of two.
private static int getPowerOfTwoForSampleRatio(final double ratio) {
    int k = Integer.highestOneBit((int) Math.floor(ratio));
    if (k == 0) return 1;
    else return k;


  1. Android doesn't provide any methods to get file path from a URI, and in most of the above answers we have hard coded some constants, which may break in feature release (sorry, I may be wrong).
  2. Before going directly going to a solution of the getting file path from a URI, try if you can solve your use case with a URI and Android default methods.



Entity Framework Join 3 Tables

This is untested, but I believe the syntax should work for a lambda query. As you join more tables with this syntax you have to drill further down into the new objects to reach the values you want to manipulate.

var fullEntries = dbContext.tbl_EntryPoint
        entryPoint => entryPoint.EID,
        entry => entry.EID,
        (entryPoint, entry) => new { entryPoint, entry }
        combinedEntry => combinedEntry.entry.TID,
        title => title.TID,
        (combinedEntry, title) => new 
            UID = combinedEntry.entry.OwnerUID,
            TID = combinedEntry.entry.TID,
            EID = combinedEntry.entryPoint.EID,
            Title = title.Title
    .Where(fullEntry => fullEntry.UID == user.UID)

Echo newline in Bash prints literal \n

POSIX 7 on echo

-e is not defined and backslashes are implementation defined:

If the first operand is -n, or if any of the operands contain a <backslash> character, the results are implementation-defined.

unless you have an optional XSI extension.

So I recommend that you should use printf instead, which is well specified:

format operand shall be used as the format string described in XBD File Format Notation [...]

the File Format Notation:

\n <newline> Move the printing position to the start of the next line.

Also keep in mind that Ubuntu 15.10 and most distros implement echo both as:

  • a Bash built-in: help echo
  • a standalone executable: which echo

which can lead to some confusion.

How to convert an address into a Google Maps Link (NOT MAP)

I know I'm very late to the game, but thought I'd contribute for posterity's sake.

I wrote a short jQuery function that will automatically turn any <address> tags into Google maps links.

See a demo here.

$(document).ready(function () {
   //Convert address tags to google map links - Michael Jasper 2012
   $('address').each(function () {
      var link = "<a href='" + encodeURIComponent( $(this).text() ) + "' target='_blank'>" + $(this).text() + "</a>";


I also came across a situation that called for generating embedded maps from the links, and though I'd share with future travelers:

View a full demo

        var embed ="<iframe width='425' height='350' frameborder='0' scrolling='no'  marginheight='0' marginwidth='0' src=';q="+ encodeURIComponent( $(this).text() ) +"&amp;output=embed'></iframe>";

C# Convert List<string> to Dictionary<string, string>

Use this:

var dict = list.ToDictionary(x => x);

See MSDN for more info.

As Pranay points out in the comments, this will fail if an item exists in the list multiple times.
Depending on your specific requirements, you can either use var dict = list.Distinct().ToDictionary(x => x); to get a dictionary of distinct items or you can use ToLookup instead:

var dict = list.ToLookup(x => x);

This will return an ILookup<string, string> which is essentially the same as IDictionary<string, IEnumerable<string>>, so you will have a list of distinct keys with each string instance under it.

Running multiple async tasks and waiting for them all to complete

Both answers didn't mention the awaitable Task.WhenAll:

var task1 = DoWorkAsync();
var task2 = DoMoreWorkAsync();

await Task.WhenAll(task1, task2);

The main difference between Task.WaitAll and Task.WhenAll is that the former will block (similar to using Wait on a single task) while the latter will not and can be awaited, yielding control back to the caller until all tasks finish.

More so, exception handling differs:


At least one of the Task instances was canceled -or- an exception was thrown during the execution of at least one of the Task instances. If a task was canceled, the AggregateException contains an OperationCanceledException in its InnerExceptions collection.


If any of the supplied tasks completes in a faulted state, the returned task will also complete in a Faulted state, where its exceptions will contain the aggregation of the set of unwrapped exceptions from each of the supplied tasks.

If none of the supplied tasks faulted but at least one of them was canceled, the returned task will end in the Canceled state.

If none of the tasks faulted and none of the tasks were canceled, the resulting task will end in the RanToCompletion state. If the supplied array/enumerable contains no tasks, the returned task will immediately transition to a RanToCompletion state before it's returned to the caller.

Refused to load the script because it violates the following Content Security Policy directive

Try replacing your meta tag with this below:

<meta http-equiv="Content-Security-Policy" content="default-src *; style-src 'self' http://* 'unsafe-inline'; script-src 'self' http://* 'unsafe-inline' 'unsafe-eval'" />

Or in addition to what you have, you should add http://* to both style-src and script-src as seen above added after 'self'.

If your server is including the Content-Security-Policy header, the header will override the meta.

What is "origin" in Git?

origin is an alias on your system for a particular remote repository. It's not actually a property of that repository.

By doing

git push origin branchname

you're saying to push to the origin repository. There's no requirement to name the remote repository origin: in fact the same repository could have a different alias for another developer.

Remotes are simply an alias that store the URL of repositories. You can see what URL belongs to each remote by using

git remote -v

In the push command, you can use remotes or you can simply use a URL directly. An example that uses the URL:

git push [email protected]:git/git.git master

Calculating the distance between 2 points

Here is my 2 cents:

double dX = x1 - x2;
double dY = y1 - y2;
double multi = dX * dX + dY * dY;
double rad = Math.Round(Math.Sqrt(multi), 3, MidpointRounding.AwayFromZero);

x1, y1 is the first coordinate and x2, y2 the second. The last line is the square root with it rounded to 3 decimal places.

Session variables in ASP.NET MVC

The answer here is correct, I however struggled to implement it in an ASP.NET MVC 3 app. I wanted to access a Session object in a controller and couldn't figure out why I kept on getting a "Instance not set to an instance of an Object error". What I noticed is that in a controller when I tried to access the session by doing the following, I kept on getting that error. This is due to the fact that this.HttpContext is part of the Controller object.

// or

However, what I wanted was the HttpContext that's part of the System.Web namespace because this is the one the Answer above suggests to use in Global.asax.cs. So I had to explicitly do the following:


this helped me, not sure if I did anything that isn't M.O. around here, but I hope it helps someone!

Expand a div to fill the remaining width

A slightly different implementation,

Two div panels(content+extra), side by side, content panel expands if extra panel is not present.


How to swap two variables in JavaScript

ES6 Destructuring:

Using an array: [a, b] = [b, a]; // my favorite

Using an object: {a, b} = {a:b, b:a}; // not bad neither

How can I pass a parameter in Action?

If you know what parameter you want to pass, take a Action<T> for the type. Example:

void LoopMethod (Action<int> code, int count) {
     for (int i = 0; i < count; i++) {

If you want the parameter to be passed to your method, make the method generic:

void LoopMethod<T> (Action<T> code, int count, T paramater) {
     for (int i = 0; i < count; i++) {

And the caller code:

Action<string> s = Console.WriteLine;
LoopMethod(s, 10, "Hello World");

Update. Your code should look like:

private void Include(IList<string> includes, Action<string> action)
    if (includes != null)
         foreach (var include in includes)

public void test()
    Action<string> dg = (s) => {
    this.Include(includes, dg);

Appending an id to a list if not already present in a string

What you are trying to do can almost certainly be achieved with a set.

>>> x = set([1,2,3])
>>> x.add(2)
>>> x
set([1, 2, 3])
>>> x.add(4)
>>> x.add(4)
>>> x
set([1, 2, 3, 4])

using a set's add method you can build your unique set of ids very quickly. Or if you already have a list

unique_ids = set(id_list)

as for getting your inputs in numeric form you can do something like

>>> ids = [int(n) for n in '350882 348521 350166\r\n'.split()]
>>> ids
[350882, 348521, 350166]

Convert a numpy.ndarray to string(or bytes) and convert it back to numpy.ndarray

I know, I am late but here is the correct way of doing it. using base64. This technique will convert the array to string.

import base64
import numpy as np
random_array = np.random.randn(32,32)
string_repr = base64.binascii.b2a_base64(random_array).decode("ascii")
array = np.frombuffer(base64.binascii.a2b_base64(string_repr.encode("ascii"))) 

For array to string

Convert binary data to a line of ASCII characters in base64 coding and decode to ASCII to get string repr.

For string to array

First, encode the string in ASCII format then Convert a block of base64 data back to binary and return the binary data.

How do I change the language of moment.js?

With momentjs 2.8+, do the following:


Gradient borders

Example for Gradient Border

Using border-image css property

Credits to : border-image in Mozilla

.grad-border {_x000D_
  height: 1px;_x000D_
  width: 85%;_x000D_
  margin: 0 auto;_x000D_
  display: flex;_x000D_
.left-border, .right-border {_x000D_
  width: 50%;_x000D_
  border-bottom: 2px solid #695f52;_x000D_
  display: inline-block;_x000D_
.left-border {_x000D_
  border-image: linear-gradient(270deg, #b3b3b3, #fff) 1;_x000D_
.right-border {_x000D_
  border-image: linear-gradient(90deg, #b3b3b3, #fff) 1;_x000D_
<div class="grad-border">_x000D_
  <div class="left-border"></div>_x000D_
  <div class="right-border"></div>_x000D_

How to stop creating .DS_Store on Mac?

Put following line into your ".profile" file.

Open .profile file and copy this line

find ~/ -name '.DS_Store' -delete

When you open terminal window it will automatically delete your .DS_Store file for you.

Measuring function execution time in R

Another possible way of doing this would be to use Sys.time():

start.time <- Sys.time()
...Relevent codes...
end.time <- Sys.time()
time.taken <- end.time - start.time

Not the most elegant way to do it, compared to the answere above , but definitely a way to do it.

IE prompts to open or save json result from server

I faced this while using jQuery FileUpload plugin.

Then I took a look in their documentation, most exactly in the Content-Type Negotiation section and followed their suggestion for Ruby/Rails.

render(json: <some-data>, content_type: request.format)

Which fixed the issue for me.

Quick Explanation: for old IE/Opera versions, this plugin will use an iframe with text/plain or text/html content-type, so if you force the response to json, browser will try download it. Using the same content-type as in the request will make it work for any browser.

Easy way to write contents of a Java InputStream to an OutputStream

As WMR mentioned, from Apache has a method called copy(InputStream,OutputStream) which does exactly what you're looking for.

So, you have:

InputStream in;
OutputStream out;
out.close(); your code.

Is there a reason you're avoiding IOUtils?

Cannot find the object because it does not exist or you do not have permissions. Error in SQL Server

In my case the sql server version on my localhost is higher than that on the production server and hence some new variables were added to the generated script from the localhost. This caused errors in creating the table in the first place. Since the creation of the table failed, subsequent query on the "NON EXISITING" table also failed. Luckily, in among the long list of the sql errors, I found this "OPTIMIZE_FOR_SEQUENTIAL_KEY = OFF" to be the new varialbe in the script causing my issue. I did a search and replace and the error went away. Hope it helps someone.

Git push existing repo to a new and different remote repo server?

If you have Existing Git repository:

cd existing_repo
git remote rename origin old-origin
git remote add origin
git push -u origin --all
git push -u origin --tags

How to copy Outlook mail message into excel using VBA or Macros

Since you have not mentioned what needs to be copied, I have left that section empty in the code below.

Also you don't need to move the email to the folder first and then run the macro in that folder. You can run the macro on the incoming mail and then move it to the folder at the same time.

This will get you started. I have commented the code so that you will not face any problem understanding it.

First paste the below mentioned code in the outlook module.


  1. Click on Tools~~>Rules and Alerts
  2. Click on "New Rule"
  3. Click on "start from a blank rule"
  4. Select "Check messages When they arrive"
  5. Under conditions, click on "with specific words in the subject"
  6. Click on "specific words" under rules description.
  7. Type the word that you want to check in the dialog box that pops up and click on "add".
  8. Click "Ok" and click next
  9. Select "move it to specified folder" and also select "run a script" in the same box
  10. In the box below, specify the specific folder and also the script (the macro that you have in module) to run.
  11. Click on finish and you are done.

When the new email arrives not only will the email move to the folder that you specify but data from it will be exported to Excel as well.


Const xlUp As Long = -4162

Sub ExportToExcel(MyMail As MailItem)
    Dim strID As String, olNS As Outlook.Namespace
    Dim olMail As Outlook.MailItem
    Dim strFileName As String

    '~~> Excel Variables
    Dim oXLApp As Object, oXLwb As Object, oXLws As Object
    Dim lRow As Long

    strID = MyMail.EntryID
    Set olNS = Application.GetNamespace("MAPI")
    Set olMail = olNS.GetItemFromID(strID)

    '~~> Establish an EXCEL application object
    On Error Resume Next
    Set oXLApp = GetObject(, "Excel.Application")

    '~~> If not found then create new instance
    If Err.Number <> 0 Then
        Set oXLApp = CreateObject("Excel.Application")
    End If
    On Error GoTo 0

    '~~> Show Excel
    oXLApp.Visible = True

    '~~> Open the relevant file
    Set oXLwb = oXLApp.Workbooks.Open("C:\Sample.xls")

    '~~> Set the relevant output sheet. Change as applicable
    Set oXLws = oXLwb.Sheets("Sheet1")

    lRow = oXLws.Range("A" & oXLApp.Rows.Count).End(xlUp).Row + 1

    '~~> Write to outlook
    With oXLws
        '~~> Code here to output data from email to Excel File
        '~~> For example
        .Range("A" & lRow).Value = olMail.Subject
        .Range("B" & lRow).Value = olMail.SenderName
    End With

    '~~> Close and Clean up Excel
    oXLwb.Close (True)
    Set oXLws = Nothing
    Set oXLwb = Nothing
    Set oXLApp = Nothing

    Set olMail = Nothing
    Set olNS = Nothing
End Sub


To extract the contents from your email body, you can split it using SPLIT() and then parsing out the relevant information from it. See this example

Dim MyAr() As String

MyAr = Split(olMail.body, vbCrLf)

For i = LBound(MyAr) To UBound(MyAr)
    '~~> This will give you the contents of your email
    '~~> on separate lines
    Debug.Print MyAr(i)
Next i

What should I do when 'svn cleanup' fails?

Things have changed with SVN 1.7, and the popular solution of deleting the log file in the .svn directory isn't feasible with the move to a database working-copy implementation.

Here's what I did that seemed to work:

  1. Delete the .svn directory for your working copy.
  2. Start a new checkout in a new, temporary directory.
  3. Cancel the checkout (we don't want to wait for everything to get pulled down).
  4. Run a cleanup on this cancelled checkout.
  5. Now we have a new .svn directory with a clean database (although no/few files)
  6. Copy this .svn into your old, corrupted working directory.
  7. Run svn update and it should bring your new partial .svn directory up to speed with your old working directory.

That's all a little confusing, process wise. Essentially, what we're doing is deleting the corrupt .svn then creating a new .svn for the same checkout path. We then move this new .svn to our old working directory and update it to the repo.

I just did this in TSVN and it seems to work fine and not require a full checkout and download.


Changing file permission in Python

All the current answers clobber the non-writing permissions: they make the file readable-but-not-executable for everybody. Granted, this is because the initial question asked for 444 permissions -- but we can do better!

Here's a solution that leaves all the individual "read" and "execute" bits untouched. I wrote verbose code to make it easy to understand; you can make it more terse if you like.

import os
import stat

def remove_write_permissions(path):
    """Remove write permissions from this path, while keeping all other permissions intact.

        path:  The path whose permissions to alter.

    current_permissions = stat.S_IMODE(os.lstat(path).st_mode)
    os.chmod(path, current_permissions & NO_WRITING)

Why does this work?

As John La Rooy pointed out,stat.S_IWUSR basically means "the bitmask for the user's write permissions". We want to set the corresponding permission bit to 0. To do that, we need the exact opposite bitmask (i.e., one with a 0 in that location, and 1's everywhere else). The ~ operator, which flips all the bits, gives us exactly that. If we apply this to any variable via the "bitwise and" operator (&), it will zero out the corresponding bit.

We need to repeat this logic with the "group" and "other" permission bits, too. Here we can save some time by just &'ing them all together (forming the NO_WRITING bit constant).

The last step is to get the current file's permissions, and actually perform the bitwise-and operation.

How do you produce a .d.ts "typings" definition file from an existing JavaScript library?

Here is some PowerShell that creates a single TypeScript definition file a library that includes multiple *.js files with modern JavaScript.

First, change all the extensions to .ts.

Get-ChildItem | foreach { Rename-Item $_ $_.Name.Replace(".js", ".ts") }

Second, use the TypeScript compiler to generate definition files. There will be a bunch of compiler errors, but we can ignore those.

Get-ChildItem | foreach { tsc $_.Name  }

Finally, combine all the *.d.ts files into one index.d.ts, removing the import statements and removing the default from each export statement.

Remove-Item index.d.ts; 

Get-ChildItem -Path *.d.ts -Exclude "Index.d.ts" | `
  foreach { Get-Content $_ } | `
  where { !$_.ToString().StartsWith("import") } | `
  foreach { $_.Replace("export default", "export") } | `
  foreach { Add-Content index.d.ts $_ }

This ends with a single, usable index.d.ts file that includes many of the definitions.

How do I test if a variable is a number in Bash?

A clear answer has already been given by @charles Dufy and others. A pure bash solution would be using the following :

if [[ "$string" =~ ^-?[0-9]+[.,]?[0-9]*$ ]]
    echo $string is a number
    echo $string is not a number

Although for real numbers it is not mandatory to have a number before the radix point.

To provide a more thorough support of floating numbers and scientific notation (many programs in C/Fortran or else will export float this way), a useful addition to this line would be the following :

if [[ "$string" =~ ^-?[0-9]*[.,]?[0-9]*[eE]?-?[0-9]+$ ]]
    echo $string is a number
    echo $string is not a number

Thus leading to a way to differentiate types of number, if you are looking for any specific type :

if [[ "$string" =~ ^-?[0-9]+$ ]]
    echo $string is an integer
elif [[ "$string" =~ ^-?[0-9]*[.,]?[0-9]*$ ]]
    echo $string is a float
elif [[ "$string" =~ ^-?[0-9]*[.,]?[0-9]*[eE]-?[0-9]+$ ]]
    echo $string is a scientific number
    echo $string is not a number

Note: We could list the syntactical requirements for decimal and scientific notation, one being to allow comma as radix point, as well as ".". We would then assert that there must be only one such radix point. There can be two +/- signs in an [Ee] float. I have learned a few more rules from Aulu's work, and tested against bad strings such as '' '-' '-E-1' '0-0'. Here are my regex/substring/expr tools that seem to be holding up:

parse_num() {
 local r=`expr "$1" : '.*\([.,]\)' 2>/dev/null | tr -d '\n'` 
 nat='^[+-]?[0-9]+[.,]?$' \
 dot="${1%[.,]*}${r}${1##*[.,]}" \
 [[ "$1" == $dot ]] && [[ "$1" =~ $float ]] || [[ "$1" =~ $nat ]]
} # usage: parse_num -123.456

Xcode iOS 8 Keyboard types not supported

Xcode: 6.4 iOS:8 I got this error as well, but for a very different reason.

//UIKeyboardTypeNumberPad needs a "Done" button    
UIBarButtonItem *doneBarButton = [[UIBarButtonItem alloc]initWithBarButtonSystemItem:UIBarButtonSystemItemDone

enhancedNumpadToolbar = [[UIToolbar alloc]init]; // previously declared
[self.enhancedNumpadToolbar setItems:@[doneBarButton]];
self.myNumberTextField.inputAccessoryView = self.enhancedNumpadToolbar; //txf previously declared

I got the same error (save mine was "type 4" rather than "type 8"), until I discovered that I was missing this line:

[self.enhancedNumpadToolbar sizeToFit];

I added it, and the sun started shining, the birds resumed chirping, and all was well with the world.

PS You would also get such an error for other mischief, such as forgetting to alloc/init.

python error: no module named pylab

The error means pylab is not part of the standard Python libraries. You will need to down-load it and install it. I think it's available Here They have installation instructions here

How to unzip a file using the command line?

Copy the below code to a batch file and execute. Below requires Winzip to be installed/accessible from your machine. Do change variables as per your need.

SET winzip_path="C:\Program Files\WinZip"
SET source_path="C:\Test"
SET output_path="C:\Output\"
SET log_file="C:\Test\unzip_log.txt"
SET file_name="*.zip"

cd %source_path%
echo Executing for %source_path% > %log_file%

FOR /f "tokens=*" %%G IN ('dir %file_name% /b') DO (
echo Processing : %%G
echo File_Name : %%G >> %log_file%
%winzip_path%\WINZIP32.EXE -e %%G %output_path%


NSRange to Range<String.Index>

The NSString version (as opposed to Swift String) of replacingCharacters(in: NSRange, with: NSString) accepts an NSRange, so one simple solution is to convert String to NSString first. The delegate and replacement method names are slightly different in Swift 3 and 2, so depending on which Swift you're using:

Swift 3.0

func textField(_ textField: UITextField,
               shouldChangeCharactersIn range: NSRange,
               replacementString string: String) -> Bool {

  let nsString = textField.text as NSString?
  let newString = nsString?.replacingCharacters(in: range, with: string)

Swift 2.x

func textField(textField: UITextField,
               shouldChangeCharactersInRange range: NSRange,
               replacementString string: String) -> Bool {

    let nsString = textField.text as NSString?
    let newString = nsString?.stringByReplacingCharactersInRange(range, withString: string)

SSRS chart does not show all labels on Horizontal axis

image: reporting services line chart horizontal axis properties

To see all dates on the report; Set Axis Type to Scalar, Set Interval to 1 -Jump Labels section Set disable auto-fit set label rotation angle as you desire.

These would help.

SQL subquery with COUNT help

This is probably the easiest way, not the prettiest though:

    (SELECT Count(*) FROM eventsTable WHERE columnName = 'Business') as RowCount
    FROM eventsTable
    WHERE columnName = 'Business'

This will also work without having to use a group by

SELECT *, COUNT(*) OVER () as RowCount
    FROM eventsTables
    WHERE columnName = 'Business'

How to open mail app from Swift

You can use simple mailto: links in iOS to open the mail app.

let email = "[email protected]"
if let url = URL(string: "mailto:\(email)") {
  if #available(iOS 10.0, *) {
  } else {

LinkButton Send Value to Code Behind OnClick

Try and retrieve the text property of the link button in the code behind:

protected void ENameLinkBtn_Click (object sender, EventArgs e)
   string val = ((LinkButton)sender).Text

Sorting an ArrayList of objects using a custom sorting order

Here's a tutorial about ordering objects:

Although I will give some examples, I would recommend to read it anyway.

There are various way to sort an ArrayList. If you want to define a natural (default) ordering, then you need to let Contact implement Comparable. Assuming that you want to sort by default on name, then do (nullchecks omitted for simplicity):

public class Contact implements Comparable<Contact> {

    private String name;
    private String phone;
    private Address address;

    public int compareTo(Contact other) {
        return name.compareTo(;

    // Add/generate getters/setters and other boilerplate.

so that you can just do

List<Contact> contacts = new ArrayList<Contact>();
// Fill it.


If you want to define an external controllable ordering (which overrides the natural ordering), then you need to create a Comparator:

List<Contact> contacts = new ArrayList<Contact>();
// Fill it.

// Now sort by address instead of name (default).
Collections.sort(contacts, new Comparator<Contact>() {
    public int compare(Contact one, Contact other) {
        return one.getAddress().compareTo(other.getAddress());

You can even define the Comparators in the Contact itself so that you can reuse them instead of recreating them everytime:

public class Contact {

    private String name;
    private String phone;
    private Address address;

    // ...

    public static Comparator<Contact> COMPARE_BY_PHONE = new Comparator<Contact>() {
        public int compare(Contact one, Contact other) {

    public static Comparator<Contact> COMPARE_BY_ADDRESS = new Comparator<Contact>() {
        public int compare(Contact one, Contact other) {
            return one.address.compareTo(other.address);


which can be used as follows:

List<Contact> contacts = new ArrayList<Contact>();
// Fill it.

// Sort by address.
Collections.sort(contacts, Contact.COMPARE_BY_ADDRESS);

// Sort later by phone.
Collections.sort(contacts, Contact.COMPARE_BY_PHONE);

And to cream the top off, you could consider to use a generic javabean comparator:

public class BeanComparator implements Comparator<Object> {

    private String getter;

    public BeanComparator(String field) {
        this.getter = "get" + field.substring(0, 1).toUpperCase() + field.substring(1);

    public int compare(Object o1, Object o2) {
        try {
            if (o1 != null && o2 != null) {
                o1 = o1.getClass().getMethod(getter, new Class[0]).invoke(o1, new Object[0]);
                o2 = o2.getClass().getMethod(getter, new Class[0]).invoke(o2, new Object[0]);
        } catch (Exception e) {
            // If this exception occurs, then it is usually a fault of the developer.
            throw new RuntimeException("Cannot compare " + o1 + " with " + o2 + " on " + getter, e);

        return (o1 == null) ? -1 : ((o2 == null) ? 1 : ((Comparable<Object>) o1).compareTo(o2));


which you can use as follows:

// Sort on "phone" field of the Contact bean.
Collections.sort(contacts, new BeanComparator("phone"));

(as you see in the code, possibly null fields are already covered to avoid NPE's during sort)

How do I create and read a value from cookie?

For those who need save objects like {foo: 'bar'}, I share my edited version of @KevinBurke's answer. I've added JSON.stringify and JSON.parse, that's all.

cookie = {

    set: function (name, value, days) {
        if (days) {
            var date = new Date();
            date.setTime(date.getTime() + (days * 24 * 60 * 60 * 1000));
            var expires = "; expires=" + date.toGMTString();
            var expires = "";
        document.cookie = name + "=" + JSON.stringify(value) + expires + "; path=/";

    get : function(name){
        var nameEQ = name + "=",
            ca = document.cookie.split(';');

        for(var i=0;i < ca.length;i++) {
          var c = ca[i];
          while (c.charAt(0)==' ') c = c.substring(1,c.length);
            if (c.indexOf(nameEQ) == 0) 
              return  JSON.parse(c.substring(nameEQ.length,c.length));

        return null;


So, now you can do things like this:

cookie.set('cookie_key', {foo: 'bar'}, 30);

cookie.get('cookie_key'); // {foo: 'bar'}

cookie.set('cookie_key', 'baz', 30);

cookie.get('cookie_key'); // 'baz'

Error ITMS-90717: "Invalid App Store Icon"

changed the icon from .png format to .jpg and everything went well.

how to create a Java Date object of midnight today and midnight tomorrow?

I know this is very old post. I thought to share my knowledge here !

For the date Mid night today with exact Time zone you can use following

public static Date getCurrentDateWithMidnightTS(){

    return new Date(System.currentTimeMillis() - (System.currentTimeMillis()%(1000*60*60*24)) - (1000*60 * 330));

Where (1000*60 * 330) is being subtracted i.e. actually related to time zone for example Indian time zone i.e. kolkata differs +5:30hrs from actual . So subtracting that with converting into milliseconds.

So change last substracted number according to you. I m creating a product i.e. only based in India So just used specific timestamp.

Difference between jQuery’s .hide() and setting CSS to display: none

See there is no difference if you use basic hide method. But jquery provides various hide method which give effects to the element. Refer below link for detailed explanation: Effects for Hide in Jquery

Detect if string contains any spaces

What you have will find a space anywhere in the string, not just between words.

If you want to find any kind of whitespace, you can use this, which uses a regular expression:

if (/\s/.test(str)) {
    // It has any kind of whitespace

\s means "any whitespace character" (spaces, tabs, vertical tabs, formfeeds, line breaks, etc.), and will find that character anywhere in the string.

According to MDN, \s is equivalent to: [ \f\n\r\t\v?\u00a0\u1680?\u180e\u2000?\u2001\u2002?\u2003\u2004?\u2005\u2006?\u2007\u2008?\u2009\u200a?\u2028\u2029??\u202f\u205f?\u3000].

For some reason, I originally read your question as "How do I see if a string contains only spaces?" and so I answered with the below. But as @CrazyTrain points out, that's not what the question says. I'll leave it, though, just in case...

If you mean literally spaces, a regex can do it:

if (/^ *$/.test(str)) {
    // It has only spaces, or is empty

That says: Match the beginning of the string (^) followed by zero or more space characters followed by the end of the string ($). Change the * to a + if you don't want to match an empty string.

If you mean whitespace as a general concept:

if (/^\s*$/.test(str)) {
    // It has only whitespace

That uses \s (whitespace) rather than the space, but is otherwise the same. (And again, change * to + if you don't want to match an empty string.)

CMD: Export all the screen content to a text file

If your batch file is not interactive and you don't need to see it run then this should work.

@echo off
call file.bat >textfile.txt 2>&1

Otherwise use a tee filter. There are many, some not NT compatible. SFK the Swiss Army Knife has a tee feature and is still being developed. Maybe that will work for you.

Converting Chart.js canvas chart to image using .toDataUrl() results in blank image

You can access afterRender hook by using plugins.

And here are all the plugin api available.

In html file:

  <canvas id="myChart"></canvas>
  <div id="imgWrap"></div>

In js file:

var chart = new Chart(ctx, {
  plugins: [{
    afterRender: function () {
      // Do anything you want

const renderIntoImage = () => {
  const canvas = document.getElementById('myChart')
  const imgWrap = document.getElementById('imgWrap')
  var img = new Image();
  img.src = canvas.toDataURL()
  imgWrap.appendChild(img) = 'none'

Matching a Forward Slash with a regex

For me, I was trying to match on the / in a date in C#. I did it just by using (\/):

string pattern = "([0-9])([0-9])?(\/)([0-9])([0-9])?(\/)(\d{4})";
string text = "Start Date: 4/1/2018";

Match m = Regex.Match(text, pattern);

if (m.Success) 
    Console.WriteLine(match.Groups[0].Value);  // 4/1/2018
    Console.WriteLine("Not Found!");

JavaScript should also be able to similarly use (\/).

MySQL Great Circle Distance (Haversine formula)

I can't comment on the above answer, but be careful with @Pavel Chuchuva's answer. That formula will not return a result if both coordinates are the same. In that case, distance is null, and so that row won't be returned with that formula as is.

I'm not a MySQL expert, but this seems to be working for me:

SELECT id, ( 3959 * acos( cos( radians(37) ) * cos( radians( lat ) ) * cos( radians( lng ) - radians(-122) ) + sin( radians(37) ) * sin( radians( lat ) ) ) ) AS distance 
FROM markers HAVING distance < 25 OR distance IS NULL ORDER BY distance LIMIT 0 , 20;

How to write a stored procedure using phpmyadmin and how to use it through php?

The new version of phpMyAdmin (3.5.1) has much better support for stored procedures; including: editing, execution, exporting, PHP code creation, and some debugging.

Make sure you are using the mysqli extension in

$cfg['Servers'][$i]['extension'] = 'mysqli';

Open any database, you'll see a new tab at the top called Routines, then select Add Routine.

The first test I did produced the following error message:

MySQL said: #1558 - Column count of mysql.proc is wrong. Expected 20, found 16. Created with MySQL 50141, now running 50163. Please use mysql_upgrade to fix this error.

Ciuly's Blog provides a good solution, assuming you have command line access. Not sure how you would fix it if you don't.

Compare two files line by line and generate the difference in another file

The Unix utility diff is meant for exactly this purpose.

$ diff -u file1 file2 > file3

See the manual and the Internet for options, different output formats, etc.

Anaconda vs. miniconda

The 2 in Anaconda2 means that the main version of Python will be 2.x rather than the 3.x installed in Anaconda3. The current release has Python 2.7.13.

The is the version number of Anaconda. The current advertised version is 4.4.0 and I assume the .1 is a minor release or for other similar use. The Windows releases, which I use, just say 4.4.0 in the file name.

Others have now explained the difference between Anaconda and Miniconda, so I'll skip that.

How could I convert data from string to long in c#

You won't be able to convert it directly to long because of the decimal point i think you should convert it into decimal and then convert it into long something like this:

String strValue[i] = "1100.25";
long l1 = Convert.ToInt64(Convert.ToDecimal(strValue));

hope this helps!

Setting width and height

You can change the aspectRatio according to your needs:

     aspectRatio:4 //(width/height)

Converting a Java Keystore into PEM Format

Converting a Java Keystore into PEM Format

The most precise answer of all must be that this is NOT possible.

A Java keystore is merely a storage facility for cryptographic keys and certificates while PEM is a file format for X.509 certificates only.

Replacing spaces with underscores in JavaScript?

const updateKey = key => console.log(key.split(' ').join('_'));
updateKey('Hello World');

C++ error: undefined reference to 'clock_gettime' and 'clock_settime'


c++ -Wall filefork.cpp -lrt -O2

For gcc version 4.6.1, -lrt must be after filefork.cpp otherwise you get a link error.

Some older gcc version doesn't care about the position.

How can I fill a column with random numbers in SQL? I get the same value in every row

If you are on SQL Server 2008 you can also use

 CRYPT_GEN_RANDOM(2) % 10000

Which seems somewhat simpler (it is also evaluated once per row as newid is - shown below)



SET col1 =  CRYPT_GEN_RANDOM(2) % 10000


Returns (2 random probably different numbers)


Mulling the unexplained downvote the only legitimate reason I can think of is that because the random number generated is between 0-65535 which is not evenly divisible by 10,000 some numbers will be slightly over represented. A way around this would be to wrap it in a scalar UDF that throws away any number over 60,000 and calls itself recursively to get a replacement number.

CREATE FUNCTION dbo.RandomNumber()
      DECLARE @Result INT

      SET @Result = CRYPT_GEN_RANDOM(2)

               WHEN @Result < 60000
                     OR @@NESTLEVEL = 32 THEN @Result % 10000
               ELSE dbo.RandomNumber()

Simulate low network connectivity for Android

have you tried this? Settings - Networks - More - Mobile Networks - Network mode - Select preferred network (2G for example).

Another method i used was mentioned above. Connect via iPhone hot spot. Hope this helps.

combining results of two select statements

While it is possible to combine the results, I would advise against doing so.

You have two fundamentally different types of queries that return a different number of rows, a different number of columns and different types of data. It would be best to leave it as it is - two separate queries.

Why Python 3.6.1 throws AttributeError: module 'enum' has no attribute 'IntFlag'?

Installing version 1.1.8 of enum34 worked for me.

I was able to fix this by adding enum34 = "==1.1.8" to pyproject.toml. Apparently enum34 had a feature in v1.1.8 that avoided this error, but this regressed in v1.1.9+. This is just a workaround though. The better solution would be for packages to use environment markers so you don't have to install enum34 at all unless needed.


Remove insignificant trailing zeros from a number?

Here's a possible solution:

var x = 1.234000 // to become 1.234;
var y = 1.234001; // stays 1.234001

eval(x) --> 1.234
eval(y) --> 1.234001

Is it more efficient to copy a vector by reserving and copying, or by creating and swapping?

They aren't the same though, are they? One is a copy, the other is a swap. Hence the function names.

My favourite is:

a = b;

Where a and b are vectors.

How to get the size of the current screen in WPF?

If you are familiar with using System.Windows.Forms class then you can just add a reference of System.Windows.Forms class to your project:

Solution Explorer -> References -> Add References... -> ( Assemblies : Framework ) -> scroll down and check System.Windows.Forms assembly -> OK.

Now you can add using System.Windows.Forms; statement and use screen in your wpf project just like before.

Java Map equivalent in C#

class Test
    Dictionary<int, string> entities;

    public string GetEntity(int code)
        // java's get method returns null when the key has no mapping
        // so we'll do the same

        string val;
        if (entities.TryGetValue(code, out val))
            return val;
            return null;

how to change text box value with jQuery?

if you want to change the text of "input",use:

     `$("#inputId").val("what you want to put")`

and if you want to change the text in "label","span","div", you can use

     `$("#containerId").text("what you want to put")`

Adding default parameter value with type hint in Python

Your second way is correct.

def foo(opts: dict = {}):


this outputs

{'opts': <class 'dict'>}

It's true that's it's not listed in PEP 484, but type hints are an application of function annotations, which are documented in PEP 3107. The syntax section makes it clear that keyword arguments works with function annotations in this way.

I strongly advise against using mutable keyword arguments. More information here.

How to check if any fields in a form are empty in php

Specify POST method in form
<form name="registrationform" action="register.php" method="post">

your form code


Websocket onerror - how to read error description?

The error Event the onerror handler receives is a simple event not containing such information:

If the user agent was required to fail the WebSocket connection or the WebSocket connection is closed with prejudice, fire a simple event named error at the WebSocket object.

You may have better luck listening for the close event, which is a CloseEvent and indeed has a CloseEvent.code property containing a numerical code according to RFC 6455 11.7 and a CloseEvent.reason string property.

Please note however, that CloseEvent.code (and CloseEvent.reason) are limited in such a way that network probing and other security issues are avoided.

How to change the color of text in javafx TextField?

Setting the -fx-text-fill works for me.

See below:

if (passed) {
    resultInfo.setStyle("-fx-text-fill: green; -fx-font-size: 16px;");
} else {
    resultInfo.setStyle("-fx-text-fill: red; -fx-font-size: 16px;");

ArrayList of String Arrays

You can't force the String arrays to have a specific size. You can do this:

private List<String[]> addresses = new ArrayList<String[]>();

but an array of any size can be added to this list.

However, as others have mentioned, the correct thing to do here is to create a separate class representing addresses. Then you would have something like:

private List<Address> addresses = new ArrayList<Address>();

Capitalize words in string

I like to go with easy process. First Change string into Array for easy iterating, then using map function change each word as you want it to be.

function capitalizeCase(str) {
    var arr = str.split(' ');
    var t;
    var newt;
    var newarr ={
        t = d.split('');
        newt =, i){
                  if(i === 0) {
                     return d.toUpperCase();
                 return d.toLowerCase();
        return newt.join('');
    var s = newarr.join(' ');
    return s;

How to convert a String into an array of Strings containing one character each

Use toCharArray() method. It splits the string into an array of characters:

String str = "aabbab";
char[] chs = str.toCharArray();

Select Tag Helper in ASP.NET Core MVC

Using the Select Tag helpers to render a SELECT element

In your GET action, create an object of your view model, load the EmployeeList collection property and send that to the view.

public IActionResult Create()
    var vm = new MyViewModel();
    vm.EmployeesList = new List<Employee>
        new Employee { Id = 1, FullName = "Shyju" },
        new Employee { Id = 2, FullName = "Bryan" }
    return View(vm);

And in your create view, create a new SelectList object from the EmployeeList property and pass that as value for the asp-items property.

@model MyViewModel
<form asp-controller="Home" asp-action="Create">

    <select asp-for="EmployeeId" 
            asp-items="@(new SelectList(Model.EmployeesList,"Id","FullName"))">
        <option>Please select one</option>

    <input type="submit"/>


And your HttpPost action method to accept the submitted form data.

public IActionResult Create(MyViewModel model)
   //  check model.EmployeeId 
   //  to do : Save and redirect


If your view model has a List<SelectListItem> as the property for your dropdown items.

public class MyViewModel
    public int EmployeeId { get; set; }
    public string Comments { get; set; }
    public List<SelectListItem> Employees { set; get; }

And in your get action,

public IActionResult Create()
    var vm = new MyViewModel();
    vm.Employees = new List<SelectListItem>
        new SelectListItem {Text = "Shyju", Value = "1"},
        new SelectListItem {Text = "Sean", Value = "2"}
    return View(vm);

And in the view, you can directly use the Employees property for the asp-items.

@model MyViewModel
<form asp-controller="Home" asp-action="Create">

    <input type="text" asp-for="Comments"/>

    <label>Lucky Employee</label>
    <select asp-for="EmployeeId" asp-items="@Model.Employees" >
        <option>Please select one</option>

    <input type="submit"/>


The class SelectListItem belongs to Microsoft.AspNet.Mvc.Rendering namespace.

Make sure you are using an explicit closing tag for the select element. If you use the self closing tag approach, the tag helper will render an empty SELECT element!

The below approach will not work

<select asp-for="EmployeeId" asp-items="@Model.Employees" />

But this will work.

<select asp-for="EmployeeId" asp-items="@Model.Employees"></select>

Getting data from your database table using entity framework

The above examples are using hard coded items for the options. So i thought i will add some sample code to get data using Entity framework as a lot of people use that.

Let's assume your DbContext object has a property called Employees, which is of type DbSet<Employee> where the Employee entity class has an Id and Name property like this

public class Employee
   public int Id { set; get; }
   public string Name { set; get; }

You can use a LINQ query to get the employees and use the Select method in your LINQ expression to create a list of SelectListItem objects for each employee.

public IActionResult Create()
    var vm = new MyViewModel();
    vm.Employees = context.Employees
                          .Select(a => new SelectListItem() {  
                              Value = a.Id.ToString(),
                              Text = a.Name
    return View(vm);

Assuming context is your db context object. The view code is same as above.

Using SelectList

Some people prefer to use SelectList class to hold the items needed to render the options.

public class MyViewModel
    public int EmployeeId { get; set; }
    public SelectList Employees { set; get; }

Now in your GET action, you can use the SelectList constructor to populate the Employees property of the view model. Make sure you are specifying the dataValueField and dataTextField parameters.

public IActionResult Create()
    var vm = new MyViewModel();
    vm.Employees = new SelectList(GetEmployees(),"Id","FirstName");
    return View(vm);
public IEnumerable<Employee> GetEmployees()
    // hard coded list for demo. 
    // You may replace with real data from database to create Employee objects
    return new List<Employee>
        new Employee { Id = 1, FirstName = "Shyju" },
        new Employee { Id = 2, FirstName = "Bryan" }

Here I am calling the GetEmployees method to get a list of Employee objects, each with an Id and FirstName property and I use those properties as DataValueField and DataTextField of the SelectList object we created. You can change the hardcoded list to a code which reads data from a database table.

The view code will be same.

<select asp-for="EmployeeId" asp-items="@Model.Employees" >
    <option>Please select one</option>

Render a SELECT element from a list of strings.

Sometimes you might want to render a select element from a list of strings. In that case, you can use the SelectList constructor which only takes IEnumerable<T>

var vm = new MyViewModel();
var items = new List<string> {"Monday", "Tuesday", "Wednesday"};
vm.Employees = new SelectList(items);
return View(vm);

The view code will be same.

Setting selected options

Some times,you might want to set one option as the default option in the SELECT element (For example, in an edit screen, you want to load the previously saved option value). To do that, you may simply set the EmployeeId property value to the value of the option you want to be selected.

public IActionResult Create()
    var vm = new MyViewModel();
    vm.Employees = new List<SelectListItem>
        new SelectListItem {Text = "Shyju", Value = "11"},
        new SelectListItem {Text = "Tom", Value = "12"},
        new SelectListItem {Text = "Jerry", Value = "13"}
    vm.EmployeeId = 12;  // Here you set the value
    return View(vm);

This will select the option Tom in the select element when the page is rendered.

Multi select dropdown

If you want to render a multi select dropdown, you can simply change your view model property which you use for asp-for attribute in your view to an array type.

public class MyViewModel
    public int[] EmployeeIds { get; set; }
    public List<SelectListItem> Employees { set; get; }

This will render the HTML markup for the select element with the multiple attribute which will allow the user to select multiple options.

@model MyViewModel
<select id="EmployeeIds" multiple="multiple" name="EmployeeIds">
    <option>Please select one</option>
    <option value="1">Shyju</option>
    <option value="2">Sean</option>

Setting selected options in multi select

Similar to single select, set the EmployeeIds property value to the an array of values you want.

public IActionResult Create()
    var vm = new MyViewModel();
    vm.Employees = new List<SelectListItem>
        new SelectListItem {Text = "Shyju", Value = "11"},
        new SelectListItem {Text = "Tom", Value = "12"},
        new SelectListItem {Text = "Jerry", Value = "13"}
    vm.EmployeeIds= new int[] { 12,13} ;  
    return View(vm);

This will select the option Tom and Jerry in the multi select element when the page is rendered.

Using ViewBag to transfer the list of items

If you do not prefer to keep a collection type property to pass the list of options to the view, you can use the dynamic ViewBag to do so.(This is not my personally recommended approach as viewbag is dynamic and your code is prone to uncatched typo errors)

public IActionResult Create()
    ViewBag.Employees = new List<SelectListItem>
        new SelectListItem {Text = "Shyju", Value = "1"},
        new SelectListItem {Text = "Sean", Value = "2"}
    return View(new MyViewModel());

and in the view

<select asp-for="EmployeeId" asp-items="@ViewBag.Employees">
    <option>Please select one</option>

Using ViewBag to transfer the list of items and setting selected option

It is same as above. All you have to do is, set the property (for which you are binding the dropdown for) value to the value of the option you want to be selected.

public IActionResult Create()
    ViewBag.Employees = new List<SelectListItem>
        new SelectListItem {Text = "Shyju", Value = "1"},
        new SelectListItem {Text = "Bryan", Value = "2"},
        new SelectListItem {Text = "Sean", Value = "3"}

    vm.EmployeeId = 2;  // This will set Bryan as selected

    return View(new MyViewModel());

and in the view

<select asp-for="EmployeeId" asp-items="@ViewBag.Employees">
    <option>Please select one</option>

Grouping items

The select tag helper method supports grouping options in a dropdown. All you have to do is, specify the Group property value of each SelectListItem in your action method.

public IActionResult Create()
    var vm = new MyViewModel();

    var group1 = new SelectListGroup { Name = "Dev Team" };
    var group2 = new SelectListGroup { Name = "QA Team" };

    var employeeList = new List<SelectListItem>()
        new SelectListItem() { Value = "1", Text = "Shyju", Group = group1 },
        new SelectListItem() { Value = "2", Text = "Bryan", Group = group1 },
        new SelectListItem() { Value = "3", Text = "Kevin", Group = group2 },
        new SelectListItem() { Value = "4", Text = "Alex", Group = group2 }
    vm.Employees = employeeList;
    return View(vm);

There is no change in the view code. the select tag helper will now render the options inside 2 optgroup items.

How do I fix a Git detached head?

Since "detached head state" has you on a temp branch, just use git checkout - which puts you on the last branch you were on.

How to set caret(cursor) position in contenteditable element (div)?

If you don't want to use jQuery you can try this approach:

public setCaretPosition() {
    const editableDiv = document.getElementById('contenteditablediv');
    const lastLine = this.input.nativeElement.innerHTML.replace(/.*?(<br>)/g, '');
    const selection = window.getSelection();
    selection.collapse(editableDiv.childNodes[editableDiv.childNodes.length - 1], lastLine.length);

editableDiv you editable element, don't forget to set an id for it. Then you need to get your innerHTML from the element and cut all brake lines. And just set collapse with next arguments.

How to replace all special character into a string using C#

Assume you want to replace symbols which are not digits or letters (and _ character as @Guffa correctly pointed):

string input = "Hello@Hello&Hello(Hello)";
string result = Regex.Replace(input, @"[^\w\d]", ",");
// Hello,Hello,Hello,Hello,

You can add another symbols which should not be replaced. E.g. if you want white space symbols to stay, then just add \s to pattern: \[^\w\d\s]

git revert back to certain commit

You can revert all your files under your working directory and index by typing following this command

git reset --hard <SHAsum of your commit>

You can also type

git reset --hard HEAD #your current head point


git reset --hard HEAD^ #your previous head point

Hope it helps

How to get HttpClient returning status code and response body?

Fluent facade API:

Response response = Request.Get(uri)
HttpResponse httpResponse = response.returnResponse();
StatusLine statusLine = httpResponse.getStatusLine();
if (statusLine.getStatusCode() == HttpStatus.SC_OK) {
    // ??????????(???????)
    String responseContent = EntityUtils.toString(

Ruby String to Date Conversion

Date.strptime(updated,"%a, %d %m %Y %H:%M:%S %Z")

Should be:

Date.strptime(updated, '%a, %d %b %Y %H:%M:%S %Z')

MySQL Select all columns from one table and some from another table

Using alias for referencing the tables to get the columns from different tables after joining them.

Select tb1.*, tb2.col1, tb2.col2 from table1 tb1 JOIN table2 tb2 on tb1.Id = tb2.Id

How to add New Column with Value to the Existing DataTable?

Add the column and update all rows in the DataTable, for example:

DataTable tbl = new DataTable();
tbl.Columns.Add(new DataColumn("ID", typeof(Int32)));
tbl.Columns.Add(new DataColumn("Name", typeof(string)));
for (Int32 i = 1; i <= 10; i++) {
    DataRow row = tbl.NewRow();
    row["ID"] = i;
    row["Name"] = i + ". row";
DataColumn newCol = new DataColumn("NewColumn", typeof(string));
newCol.AllowDBNull = true;
foreach (DataRow row in tbl.Rows) {
    row["NewColumn"] = "You DropDownList value";
//if you don't want to allow null-values'
newCol.AllowDBNull = false;

Twig for loop for arrays with keys

There's this example in the SensioLab page on the for tag:

    {% for key, user in users %}
        <li>{{ key }}: {{ user.username|e }}</li>
    {% endfor %}

Splitting a dataframe string column into multiple different columns

Is this what you are trying to do?

# Our data
text <- c("F.US.CLE.V13", "F.US.CA6.U13", "F.US.CA6.U13", "F.US.CA6.U13", 
"F.US.CA6.U13", "F.US.CA6.U13", "F.US.CA6.U13", "F.US.CA6.U13", 
"F.US.DL.U13", "F.US.DL.U13", "F.US.DL.U13", "F.US.DL.Z13", "F.US.DL.Z13"

#  Split into individual elements by the '.' character
#  Remember to escape it, because '.' by itself matches any single character
elems <- unlist( strsplit( text , "\\." ) )

#  We know the dataframe should have 4 columns, so make a matrix
m <- matrix( elems , ncol = 4 , byrow = TRUE )

#  Coerce to data.frame - head() is just to illustrate the top portion
head( m ) )
#  V1 V2  V3  V4
#1  F US CLE V13
#2  F US CA6 U13
#3  F US CA6 U13
#4  F US CA6 U13
#5  F US CA6 U13
#6  F US CA6 U13

Angular 4 default radio button checked by default

We can use [(ngModel)] in following way and have a value selection variable radioSelected

Example tutorial

Demo Link


  <div class="text-center mt-5">
  <h4>Selected value is {{}}</h4>

    <ul class="list-group">
          <li class="list-group-item"  *ngFor="let item of itemsList">
            <input type="radio" [(ngModel)]="radioSelected" name="list_name" value="{{item.value}}" (change)="onItemChange(item)"/> 





  import {Item} from '../app/item';
  import {ITEMS} from '../app/mock-data';

    selector: 'app-root',
    templateUrl: './app.component.html',
    styleUrls: ['./app.component.css']
  export class AppComponent {
    title = 'app';
    itemsList: Item[] = ITEMS;

      constructor() {
        this.itemsList = ITEMS;
        //Selecting Default Radio item here
        this.radioSelected = "item_3";

      // Get row item from array  
        this.radioSel = ITEMS.find(Item => Item.value === this.radioSelected);
        this.radioSelectedString = JSON.stringify(this.radioSel);
      // Radio Change Event


Sample Data for Listing

        export const ITEMS: Item[] = [
                name:'Item 1',
                name:'Item 2',
                name:'Item 3',
                name:'Item 4',
                    name:'Item 5',

chai test array equality doesn't work as expected

For expect, .equal will compare objects rather than their data, and in your case it is two different arrays.

Use .eql in order to deeply compare values. Check out this link.
Or you could use .deep.equal in order to simulate same as .eql.
Or in your case you might want to check .members.

For asserts you can use .deepEqual, link.

Microsoft Excel mangles Diacritics in .csv files?

I can only get CSV to parse properly in Excel 2007 as tab-separated little-endian UTF-16 starting with the proper byte order mark.

How do I compare two columns for equality in SQL Server?

What's wrong with CASE for this? In order to see the result, you'll need at least a byte, and that's what you get with a single character.


should work fine, and for all intents and purposes accomplishes the same thing as using a bit field.

How to get current time and date in Android

For a customized time and date format:

    SimpleDateFormat dateFormat= new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ssZZZZZ",Locale.ENGLISH);
    String cDateTime=dateFormat.format(new Date());

Output is like below format: 2015-06-18T10:15:56-05:00

Android: keeping a background service alive (preventing process death)

As Dave already pointed out, you could run your Service with foreground priority. But this practice should only be used when it's absolutely necessary, i.e. when it would cause a bad user experience if the Service got killed by Android. This is what the "foreground" really means: Your app is somehow in the foreground and the user would notice it immediately if it's killed (e.g. because it played a song or a video).

In most cases, requesting foreground priority for your Service is contraproductive!

Why is that? When Android decides to kill a Service, it does so because it's short of resources (usually RAM). Based on the different priority classes, Android decides which running processes, and this included services, to terminate in order to free resources. This is a healthy process that you want to happen so that the user has a smooth experience. If you request foreground priority, without a good reason, just to keep your service from being killed, it will most likely cause a bad user experience. Or can you guarantee that your service stays within a minimal resource consumption and has no memory leaks?1

Android provides sticky services to mark services that should be restarted after some grace period if they got killed. This restart usually happens within a few seconds.

Image you want to write an XMPP client for Android. Should you request foreground priority for the Service which contains your XMPP connection? Definitely no, there is absolutely no reason to do so. But you want to use START_STICKY as return flag for your service's onStartCommand method. So that your service is stopped when there is resource pressure and restarted once the situation is back to normal.

1: I am pretty sure that many Android apps have memory leaks. It something the casual (desktop) programmer doesn't care that much about.

Android: Changing Background-Color of the Activity (Main View)

i don't know if it's the answer to your question but you can try setting the background color in the xml layout like this. It is easy, it always works

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

<LinearLayout xmlns:android=""













You can also do more fancy things with backgrounds by creating an xml background file with gradients which are cool and semi transparent, and refer to it for other use see example below:

the background.xml layout

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="">
            android:type="linear" />

your layout

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

<LinearLayout xmlns:android=""













How to add List<> to a List<> in

  1. Use Concat or Union extension methods. You have to make sure that you have this direction using System.Linq; in order to use LINQ extensions methods.

  2. Use the AddRange method.

Kafka consumer list

High level consumers are registered into Zookeeper, so you can fetch a list from ZK, similarly to the way fetches the list of topics. I don't think there's a way to collect all consumers; any application sending in a few consume requests is actually a "consumer", and you cannot tell whether they are done already.

On the consumer side, there's a JMX metric exposed to monitor the lag. Also, there is Burrow for lag monitoring.

Subscript out of range error in this Excel VBA script

This looks a little better than your previous version but get rid of that .Activate on that line and see if you still get that error.

Dim sh1 As Worksheet
set sh1 = Workbooks.Add(filenum(lngPosition) & ".csv")

Creates a worksheet object. Not until you create that object do you want to start working with it. Once you have that object you can do the following:


The sh1. explicitely tells Excel which object you are saying to work with... otherwise if you start selecting other worksheets while this code is running you could wind up pasting data to the wrong place.

Calling a javascript function recursively

Here's one very simple example:

var counter = 0;

function getSlug(tokens) {
    var slug = '';

    if (!!tokens.length) {
        slug = tokens.shift();
        slug = slug.toLowerCase();
        slug += getSlug(tokens);

        counter += 1;
        console.log('THE SLUG ELEMENT IS: %s, counter is: %s', slug, counter);

    return slug;

var mySlug = getSlug(['This', 'Is', 'My', 'Slug']);
console.log('THE SLUG IS: %s', mySlug);

Notice that the counter counts "backwards" in regards to what slug's value is. This is because of the position at which we are logging these values, as the function recurs before logging -- so, we essentially keep nesting deeper and deeper into the call-stack before logging takes place.

Once the recursion meets the final call-stack item, it trampolines "out" of the function calls, whereas, the first increment of counter occurs inside of the last nested call.

I know this is not a "fix" on the Questioner's code, but given the title I thought I'd generically exemplify Recursion for a better understanding of recursion, outright.

Dockerfile copy keep subdirectory structure

Remove star from COPY, with this Dockerfile:

FROM ubuntu
COPY files/ /files/
RUN ls -la /files/*

Structure is there:

$ docker build .
Sending build context to Docker daemon 5.632 kB
Sending build context to Docker daemon 
Step 0 : FROM ubuntu
 ---> d0955f21bf24
Step 1 : COPY files/ /files/
 ---> 5cc4ae8708a6
Removing intermediate container c6f7f7ec8ccf
Step 2 : RUN ls -la /files/*
 ---> Running in 08ab9a1e042f
total 8
drwxr-xr-x 2 root root 4096 May 13 16:04 .
drwxr-xr-x 4 root root 4096 May 13 16:05 ..
-rw-r--r-- 1 root root    0 May 13 16:04 file1
-rw-r--r-- 1 root root    0 May 13 16:04 file2

total 8
drwxr-xr-x 2 root root 4096 May 13 16:04 .
drwxr-xr-x 4 root root 4096 May 13 16:05 ..
-rw-r--r-- 1 root root    0 May 13 16:04 file1
-rw-r--r-- 1 root root    0 May 13 16:04 file2
 ---> 03ff0a5d0e4b
Removing intermediate container 08ab9a1e042f
Successfully built 03ff0a5d0e4b

How to specify 64 bit integers in c

Use int64_t, that portable C99 code.

int64_t var = 0x0000444400004444LL;

For printing:

#include <inttypes.h>

printf("blabla %" PRIi64 " blabla\n", var);

jQuery - how can I find the element with a certain id?


var verificaHorario = $("#tbIntervalos").find("#" + horaInicial);

will find you the td that needs to be blocked.

Actually this will also do:

var verificaHorario = $("#" + horaInicial);

Testing for the size() of the wrapped set will answer your question regarding the existence of the id.

Is it necessary to write HEAD, BODY and HTML tags?

Firebug shows this correctly because your Browser automagically fixes the bad markup for you. This behaviour is not specified anywhere and can (will) vary from browser to browser. Those tags are required by the DOCTYPE you're using and should not be omitted.

The html element is the root element of every html page. If you look at all other elements' description it says where an element can be used (and almost all elements require either head or body).

"Could not find Developer Disk Image"

Xcode 7.0.1 and iOS 9.1 are incompatible. You will need to update your version of Xcode via the Mac app store.

If your iOS version is lower then the Xcode version on the other hand, you can change the deployment target for a lower version of iOS by going to the General Settings and under Deployment set your Deployment Target:

enter image description here


Xcode 7.1 does not include iOS 9.2 beta SDK. Upgraded to Xcode to 7.2 beta by downloading it from the Xcode website.

php mail setup in xampp

Unless you have a mail server set up on your local computer, setting SMTP = localhost won't have any effect.

In days gone by (long ago), it was sufficient to set the value of SMTP to the address of your ISP's SMTP server. This now rarely works because most ISPs insist on authentication with a username and password. However, the PHP mail() function doesn't support SMTP authentication. It's designed to work directly with the mail transport agent of the local server.

You either need to set up a local mail server or to use a PHP classs that supports SMTP authentication, such as Zend_Mail or PHPMailer. The simplest solution, however, is to upload your mail processing script to your remote server.

How do I get the key at a specific index from a Dictionary in Swift?

You can iterate over a dictionary and grab an index with for-in and enumerate (like others have said, there is no guarantee it will come out ordered like below)

let dict = ["c": 123, "d": 045, "a": 456]

for (index, entry) in enumerate(dict) {
    println(index)   // 0       1        2
    println(entry)   // (d, 45) (c, 123) (a, 456)

If you want to sort first..

var sortedKeysArray = sorted(dict) { $0.0 < $1.0 }
println(sortedKeysArray)   // [(a, 456), (c, 123), (d, 45)]

var sortedValuesArray = sorted(dict) { $0.1 < $1.1 }
println(sortedValuesArray) // [(d, 45), (c, 123), (a, 456)]

then iterate.

for (index, entry) in enumerate(sortedKeysArray) {
    println(index)    // 0   1   2
    println(entry.0)  // a   c   d
    println(entry.1)  // 456 123 45

If you want to create an ordered dictionary, you should look into Generics.

ng-repeat: access key and value for each object in array of objects

In case this is an option for you, if you put your data into object form it works the way I think you're hoping for:

$scope.steps = {
 companyName: true,
 businessType: true,
 physicalAddress: true

Here's a fiddle of this:

How to uninstall pip on OSX?

Since pip is a package, pip uninstall pip Will do it.
EDIT: If that does not work, try sudo -H pip uninstall pip.

selecting unique values from a column

There is a specific keyword for the achieving the same.

FROM   buy 

CronJob not running

I want to add 2 points that I learned:

  1. Cron config files put in /etc/cron.d/ should not contain a dot (.). Otherwise, it won't be read by cron.
  2. If the user running your command is not in /etc/shadow. It won't be allowed to schedule cron.



resize font to fit in a div (on one line)

I wasn't in love with the other solutions out there, so, here's another one. It requires the tag you're resizing the text inside of:

  1. Be fixed height

  2. Not be so long that it'd overrun the boundaries at 10px - the idea being, you don't want it to shoot below that and resize text to become unreadable. Not an issue in our use case, but if it's possible in yours you'd want to give some thoughts to separately truncating before running this.

It uses a binary search to find the best size so I suspect it outperforms a lot of the other solutions here and elsewhere that just step the font-size down by a pixel over and over. Most browsers today support decimals in font sizes as well, and this script has some benefits there since it will get to within .1px of the best answer, whatever that is, even if it's a relatively long decimal. You could easily change the max - fontSize < .1 to some other value than .1 to get less precision for less CPU usage.




(function() {
    function resizeLoop(testTag, checkSize) {
        var fontSize = 10;
        var min = 10;
        var max = 0;
        var exceeded = false;

        for(var i = 0; i < 30; i++) {
            testTag.css('font-size', fontSize);
            if (checkSize(testTag)) {
                max = fontSize;
                fontSize = (fontSize + min) / 2;
            } else {
                if (max == 0) {
                    // Start by growing exponentially
                    min = fontSize;
                    fontSize *= 2;
                } else {
                    // If we're within .1px of max anyway, call it a day
                    if (max - fontSize < .1)

                    // If we've seen a max, move half way to it
                    min = fontSize;
                    fontSize = (fontSize + max) / 2;

        return fontSize;

    function sizeText(tag) {
        var width = tag.width();
        var height = tag.height();

        // Clone original tag and append to the same place so we keep its original styles, especially font
        var testTag = tag.clone(true)
            position: 'absolute',
            left: 0, top: 0,
            width: 'auto', height: 'auto'

        var fontSize;

        // TODO: This decision of 10 characters is arbitrary. Come up
        // with a smarter decision basis.
        if (tag.text().length < 10) {
            fontSize = resizeLoop(testTag, function(t) {
                return t.width() > width || t.height() > height;
        } else {
            testTag.css('width', width);
            fontSize = resizeLoop(testTag, function(t) {
                return t.height() > height;

        tag.css('font-size', fontSize);

    $.fn.fitText = function() {
        this.each(function(i, tag) {

Android, landscape only orientation?

You can try with


How to copy commits from one branch to another?

git cherry-pick : Apply the changes introduced by some existing commits

Assume we have branch A with (X, Y, Z) commits. We need to add these commits to branch B. We are going to use the cherry-pick operations.

When we use cherry-pick, we should add commits on branch B in the same chronological order that the commits appear in Branch A.

cherry-pick does support a range of commits, but if you have merge commits in that range, it gets really complicated

git checkout B
git cherry-pick SHA-COMMIT-X
git cherry-pick SHA-COMMIT-Y
git cherry-pick SHA-COMMIT-Z

Example of workflow :

enter image description here

We can use cherry-pick with options

-e or --edit : With this option, git cherry-pick will let you edit the commit message prior to committing.

-n or --no-commit : Usually the command automatically creates a sequence of commits. This flag applies the changes necessary to cherry-pick each named commit to your working tree and the index, without making any commit. In addition, when this option is used, your index does not have to match the HEAD commit. The cherry-pick is done against the beginning state of your index.

Here an interesting article concerning cherry-pick.

What are Long-Polling, Websockets, Server-Sent Events (SSE) and Comet?

You can easily use Node.JS in your web app only for real-time communication. Node.JS is really powerful when it's about WebSockets. Therefore "PHP Notifications via Node.js" would be a great concept.

See this example: Creating a Real-Time Chat App with PHP and Node.js

Custom UITableViewCell from nib in Swift

Another method that may work for you (it's how I do it) is registering a class.

Assume you create a custom tableView like the following:

class UICustomTableViewCell: UITableViewCell {...}

You can then register this cell in whatever UITableViewController you will be displaying it in with "registerClass":

override func viewDidLoad() {
    tableView.registerClass(UICustomTableViewCell.self, forCellReuseIdentifier: "UICustomTableViewCellIdentifier")

And you can call it as you would expect in the cell for row method:

override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
    let cell = tableView.dequeueReusableCellWithIdentifier("UICustomTableViewCellIdentifier", forIndexPath: indexPath) as! UICustomTableViewCell
    return cell

Append an object to a list in R in amortized constant time, O(1)?

in fact there is a subtelty with the c() function. If you do:

x <- list()
x <- c(x,2)
x = c(x,"foo")

you will obtain as expected:


[1] "foo"

but if you add a matrix with x <- c(x, matrix(5,2,2), your list will have another 4 elements of value 5 ! You would better do:

x <- c(x, list(matrix(5,2,2))

It works for any other object and you will obtain as expected:


[1] "foo"

     [,1] [,2]
[1,]    5    5
[2,]    5    5

Finally, your function becomes:

push <- function(l, ...) c(l, list(...))

and it works for any type of object. You can be smarter and do:

push_back <- function(l, ...) c(l, list(...))
push_front <- function(l, ...) c(list(...), l)

Increasing the maximum post size

You can specify both max post size and max file size limit in php.ini

post_max_size = 64M
upload_max_filesize = 64M

How to add a local repo and treat it as a remote repo

If your goal is to keep a local copy of the repository for easy backup or for sticking onto an external drive or sharing via cloud storage (Dropbox, etc) you may want to use a bare repository. This allows you to create a copy of the repository without a working directory, optimized for sharing.

For example:

$ git init --bare ~/repos/myproject.git
$ cd /path/to/existing/repo
$ git remote add origin ~/repos/myproject.git
$ git push origin master

Similarly you can clone as if this were a remote repo:

$ git clone ~/repos/myproject.git

Regular expression for not allowing spaces in the input field

Use + plus sign (Match one or more of the previous items),

var regexp = /^\S+$/

How to make rounded percentages add up to 100%

Here's a Ruby gem that implements the Largest Remainder method:

To use:

a ={ BigDecimal('0.3334') }
# => [#<BigDecimal:887b6c8,'0.3334E0',9(18)>, #<BigDecimal:887b600,'0.3334E0',9(18)>, #<BigDecimal:887b4c0,'0.3334E0',9(18)>]
a = LareRound.round(a,2)
# => [#<BigDecimal:8867330,'0.34E0',9(36)>, #<BigDecimal:8867290,'0.33E0',9(36)>, #<BigDecimal:88671f0,'0.33E0',9(36)>]
# => 1.0

X11/Xlib.h not found in Ubuntu

A quick search using...

apt search Xlib.h

Turns up the package libx11-dev but you shouldn't need this for pure OpenGL programming. What tutorial are you using?

You can add Xlib.h to your system by running the following...

sudo apt install libx11-dev

Convert array into csv

The accepted answer from Paul is great. I've made a small extension to this which is very useful if you have an multidimensional array like this (which is quite common):

    [0] => Array
            [a] => "a"
            [b] => "b"

    [1] => Array
            [a] => "a2"
            [b] => "b2"

    [2] => Array
            [a] => "a3"
            [b] => "b3"

    [3] => Array
            [a] => "a4"
            [b] => "b4"

    [4] => Array
            [a] => "a5"
            [b] => "b5"


So I just took Paul's function from above:

  * Formats a line (passed as a fields  array) as CSV and returns the CSV as a string.
  * Adapted from
function arrayToCsv( array &$fields, $delimiter = ';', $enclosure = '"', $encloseAll = false, $nullToMysqlNull = false ) {
    $delimiter_esc = preg_quote($delimiter, '/');
    $enclosure_esc = preg_quote($enclosure, '/');

    $output = array();
    foreach ( $fields as $field ) {
        if ($field === null && $nullToMysqlNull) {
            $output[] = 'NULL';

        // Enclose fields containing $delimiter, $enclosure or whitespace
        if ( $encloseAll || preg_match( "/(?:${delimiter_esc}|${enclosure_esc}|\s)/", $field ) ) {
            $output[] = $enclosure . str_replace($enclosure, $enclosure . $enclosure, $field) . $enclosure;
        else {
            $output[] = $field;

    return implode( $delimiter, $output );

And added this:

function a2c($array, $glue = "\n")
    $ret = [];
    foreach ($array as $item) {
        $ret[] = arrayToCsv($item);
    return implode($glue, $ret);

So you can just call:

$csv = a2c($array);

If you want a special line ending you can use the optional parameter "glue" for this.

MySQL's now() +1 day

You can use:


If you are only interested in the date, not the date and time then you can use CURDATE instead of NOW:


How can I send JSON response in symfony2 controller

To complete @thecatontheflat answer I would recommend to also wrap your action inside of a try … catch block. This will prevent your JSON endpoint from breaking on exceptions. Here's the skeleton I use:

public function someAction()
    try {

        // Your logic here...

        return new JsonResponse([
            'success' => true,
            'data'    => [] // Your data here

    } catch (\Exception $exception) {

        return new JsonResponse([
            'success' => false,
            'code'    => $exception->getCode(),
            'message' => $exception->getMessage(),


This way your endpoint will behave consistently even in case of errors and you will be able to treat them right on a client side.

How to use a dot "." to access members of dictionary?

I tried this:

class dotdict(dict):
    def __getattr__(self, name):
        return self[name]

you can try __getattribute__ too.

make every dict a type of dotdict would be good enough, if you want to init this from a multi-layer dict, try implement __init__ too.

How to upgrade R in ubuntu?

Since R is already installed, you should be able to upgrade it with this method. First of all, you may want to have the packages you installed in the previous version in the new one,so it is convenient to check this post. Then, follow the instructions from here

  1. Open the sources.list file:

     sudo nano /etc/apt/sources.list    
  2. Add a line with the source from where the packages will be retrieved. For example:

     deb version/

    Replace with whatever mirror you would like to use, and replace version/ with whatever version of Ubuntu you are using (eg, trusty/, xenial/, and so on). If you're getting a "Malformed line error", check to see if you have a space between /ubuntu/ and version/.

  3. Fetch the secure APT key:

     gpg --keyserver --recv-key E298A3A825C0D65DFD57CBB651716619E084DAB9


    gpg --hkp://keyserver --recv-key E298A3A825C0D65DFD57CBB651716619E084DAB9
  1. Add it to keyring:

     gpg -a --export E084DAB9 | sudo apt-key add -
  2. Update your sources and upgrade your installation:

     sudo apt-get update && sudo apt-get upgrade
  3. Install the new version

     sudo apt-get install r-base-dev
  4. Recover your old packages following the solution that best suits to you (see this). For instance, to recover all the packages (not only those from CRAN) the idea is:

-- copy the packages from R-oldversion/library to R-newversion/library, (do not overwrite a package if it already exists in the new version!).

-- Run the R command update.packages(checkBuilt=TRUE, ask=FALSE).

Firebase onMessageReceived not called when app in background

The backend I'm working with is using Notification messages and not Data messages. So after reading all the answers I tried to retrieve the extras from the bundle of the intent that comes to the launched activity. But no matter which keys I tried to retrieve from getIntent().getExtras();, the value was always null.

However, I finally found a way to send data using Notification messages and retrieve it from the intent.

The key here is to add the data payload to the Notification message.


    "data": {
        "message": "message_body",
        "title": "message_title"
    "notification": {
        "body": "test body",
        "title": "test title"
    "to": "E4An.."

After you do this, you will be able to get your info in this way:

intent.getExtras().getString("title") will be message_title

and intent.getExtras().getString("message") will be message_body


How to pass objects to functions in C++?

Since no one mentioned I am adding on it, When you pass a object to a function in c++ the default copy constructor of the object is called if you dont have one which creates a clone of the object and then pass it to the method, so when you change the object values that will reflect on the copy of the object instead of the original object, that is the problem in c++, So if you make all the class attributes to be pointers, then the copy constructors will copy the addresses of the pointer attributes , so when the method invocations on the object which manipulates the values stored in pointer attributes addresses, the changes also reflect in the original object which is passed as a parameter, so this can behave same a Java but dont forget that all your class attributes must be pointers, also you should change the values of pointers, will be much clear with code explanation.

Class CPlusPlusJavaFunctionality {
         attribute = new int;
         *attribute = value;

       void setValue(int value){
           *attribute = value;

       void getValue(){
          return *attribute;

       ~ CPlusPlusJavaFuncitonality(){

       int *attribute;

void changeObjectAttribute(CPlusPlusJavaFunctionality obj, int value){
   int* prt = obj.attribute;
   *ptr = value;

int main(){

   CPlusPlusJavaFunctionality obj;


   cout<< obj.getValue();  //output: 10

   changeObjectAttribute(obj, 15);

   cout<< obj.getValue();  //output: 15

But this is not good idea as you will be ending up writing lot of code involving with pointers, which are prone for memory leaks and do not forget to call destructors. And to avoid this c++ have copy constructors where you will create new memory when the objects containing pointers are passed to function arguments which will stop manipulating other objects data, Java does pass by value and value is reference, so it do not require copy constructors.

Resetting remote to a certain commit

If you want a previous version of file, I would recommend using git checkout.

git checkout <commit-hash>

Doing this will send you back in time, it does not affect the current state of your project, you can come to mainline git checkout mainline

but when you add a file in the argument, that file is brought back to you from a previous time to your current project time, i.e. your current project is changed and needs to be committed.

git checkout <commit-hash> -- file_name
git add .
git commit -m 'file brought from previous time'
git push

The advantage of this is that it does not delete history, and neither does revert a particular code changes (git revert)

Check more here