Programs & Examples On #Culerity

Find Facebook user (url to profile page) by known email address

WARNING: Old and outdated answer. Do not use

I think that you will have to go for your last solution, scraping the result page of the search, because you can only search by email with the API into those users that have authorized your APP (and you will need one because the token that FB provides in the examples has an expiry date and you need extended permissions to access the user's email).

The only approach that I have not tried, but I think it's limited in the same way, is FQL. Something like

SELECT * FROM user WHERE email '[email protected]'

Stored Procedure parameter default value - is this a constant or a variable

It has to be a constant - the value has to be computable at the time that the procedure is created, and that one computation has to provide the value that will always be used.

Look at the definition of sys.all_parameters:

default_value sql_variant If has_default_value is 1, the value of this column is the value of the default for the parameter; otherwise, NULL.

That is, whatever the default for a parameter is, it has to fit in that column.

As Alex K pointed out in the comments, you can just do:

CREATE PROCEDURE [dbo].[problemParam] 
    @StartDate INT = NULL,
    @EndDate INT = NULL
   SET @StartDate = COALESCE(@StartDate,CONVERT(INT,(CONVERT(CHAR(8),GETDATE()-130,112))))

provided that NULL isn't intended to be a valid value for @StartDate.

As to the blog post you linked to in the comments - that's talking about a very specific context - that, the result of evaluating GETDATE() within the context of a single query is often considered to be constant. I don't know of many people (unlike the blog author) who would consider a separate expression inside a UDF to be part of the same query as the query that calls the UDF.

How do I get a PHP class constructor to call its parent's parent's constructor?

The ugly workaround would be to pass a boolean param to Papa indicating that you do not wish to parse the code contained in it's constructor. i.e:

// main class that everything inherits
class Grandpa 
    public function __construct()



class Papa extends Grandpa
    public function __construct($bypass = false)
        // only perform actions inside if not bypassing
        if (!$bypass) {

        // call Grandpa's constructor

class Kiddo extends Papa
    public function __construct()
        $bypassPapa = true;

React - uncaught TypeError: Cannot read property 'setState' of undefined

When using ES6 code in React always use arrow functions, because the this context is automatically binded with it

Use this:

(videos) => {
    this.setState({ videos: videos });

instead of:

function(videos) {
    this.setState({ videos: videos });

Could not load file or assembly version

for version 11 download the Microsoft SQL Server 2012 Feature Pack

  • ENU\x64\SQLSysClrTypes.msi
  • ENU\x64\SharedManagementObjects.msi

for version 12 download the Microsoft SQL Server 2014 SP2 Feature Pack

  • ENU\x64\SQLSysClrTypes.msi
  • ENU\x64\SharedManagementObjects.msi

box-shadow on bootstrap 3 container

For those wanting the box-shadow on the col-* container itself and not on the .container, you can add another div just inside the col-* element, and add the shadow to that. This element will not have the padding, and therefor not interfere.

The first image has the box-shadow on the col-* element. Because of the 15px padding on the col element, the shadow is pushed to the outside of the div element rather than on the visual edges of it.

box-shadow on col-* element

<div class="col-md-4" style="box-shadow: 0px 2px 25px rgba(0, 0, 0, .25);">
    <div class="thumbnail">
        {!! HTML::image('images/sampleImage.png') !!}

The second image has a wrapper div with the box-shadow on it. This will place the box-shadow on the visual edges of the element.

box-shadow on wrapper div

<div class="col-md-4">
    <div id="wrapper-div" style="box-shadow: 0px 2px 25px rgba(0, 0, 0, .25);">
        <div class="thumbnail">
            {!! HTML::image('images/sampleImage.png') !!}

Java HashMap: How to get a key and value by index?

You can iterate over keys by calling map.keySet(), or iterate over the entries by calling map.entrySet(). Iterating over entries will probably be faster.

for (Map.Entry<String, List<String>> entry : map.entrySet()) {
    List<String> list = entry.getValue();
    // Do things with the list

If you want to ensure that you iterate over the keys in the same order you inserted them then use a LinkedHashMap.

By the way, I'd recommend changing the declared type of the map to <String, List<String>>. Always best to declare types in terms of the interface rather than the implementation.

How to write trycatch in R

tryCatch has a slightly complex syntax structure. However, once we understand the 4 parts which constitute a complete tryCatch call as shown below, it becomes easy to remember:

expr: [Required] R code(s) to be evaluated

error : [Optional] What should run if an error occured while evaluating the codes in expr

warning : [Optional] What should run if a warning occured while evaluating the codes in expr

finally : [Optional] What should run just before quitting the tryCatch call, irrespective of if expr ran successfully, with an error, or with a warning

    expr = {
        # Your code...
        # goes here...
        # ...
    error = function(e){ 
        # (Optional)
        # Do this if an error is caught...
    warning = function(w){
        # (Optional)
        # Do this if an warning is caught...
    finally = {
        # (Optional)
        # Do this at the end before quitting the tryCatch structure...

Thus, a toy example, to calculate the log of a value might look like:

log_calculator <- function(x){
        expr = {
            message("Successfully executed the log(x) call.")
        error = function(e){
            message('Caught an error!')
        warning = function(w){
            message('Caught an warning!')
        finally = {
            message('All done, quitting.')

Now, running three cases:

A valid case

# 2.30258509299405
# Successfully executed the log(x) call.
# All done, quitting.

A "warning" case

# Caught an warning!
# <simpleWarning in log(x): NaNs produced>
# All done, quitting.

An "error" case

# Caught an error!
# <simpleError in log(x): non-numeric argument to mathematical function>
# All done, quitting.

I've written about some useful use-cases which I use regularly. Find more details here:

Hope this is helpful.

CardView background color always white

Kotlin for XML



cardName.setCardBackgroundColor(ContextCompat.getColor(this, R.color.colorGray));

Is it possible to deserialize XML into List<T>?

How about

XmlSerializer xs = new XmlSerializer(typeof(user[]));
using (Stream ins = File.Open(@"c:\some.xml", FileMode.Open))
foreach (user o in (user[])xs.Deserialize(ins))

Not particularly fancy but it should work.

localhost refused to connect Error in visual studio

Try deleting cookies for your localhost

enter image description here

How can I scroll a div to be visible in ReactJS?

With reacts Hooks:

  1. Import
import ReactDOM from 'react-dom';
import React, {useRef} from 'react';
  1. Make new hook:
const divRef = useRef<HTMLDivElement>(null);
  1. Add new Div
<div ref={divRef}/>
  1. Scroll function:
const scrollToDivRef  = () => {
    let node = ReactDOM.findDOMNode(divRef.current) as Element;
    node.scrollIntoView({block: 'start', behavior: 'smooth'});

Parsing JSON array with PHP foreach

You maybe wanted to do the following:

foreach($user->data as $mydata)

         echo $mydata->name . "\n";
         foreach($mydata->values as $values)
              echo $values->value . "\n";

What's the difference between next() and nextLine() methods from Scanner class?

In short: if you are inputting a string array of length t, then Scanner#nextLine() expects t lines, each entry in the string array is differentiated from the other by enter key.And Scanner#next() will keep taking inputs till you press enter but stores string(word) inside the array, which is separated by whitespace.

Lets have a look at following snippet of code

    Scanner in = new Scanner(;
    int t = in.nextInt();
    String[] s = new String[t];

    for (int i = 0; i < t; i++) {
        s[i] =;

when I run above snippet of code in my IDE (lets say for string length 2),it does not matter whether I enter my string as

Input as :- abcd abcd or

Input as :-



Output will be like abcd


But if in same code we replace next() method by nextLine()

    Scanner in = new Scanner(;
    int t = in.nextInt();
    String[] s = new String[t];

    for (int i = 0; i < t; i++) {
        s[i] = in.nextLine();

Then if you enter input on prompt as - abcd abcd

Output is :-

abcd abcd

and if you enter the input on prompt as abcd (and if you press enter to enter next abcd in another line, the input prompt will just exit and you will get the output)

Output is:-


remove url parameters with javascript or jquery

Hmm... Looking for better way... here it is

var onlyUrl = window.location.href.replace(,'');

Java String declaration

String s1 = "Welcome"; // Does not create a new instance  
String s2 = new String("Welcome"); // Creates two objects and one reference variable  

how to force maven to update local repo

try using -U (aka --update-snapshots) when you run maven

And make sure the dependency definition is correct

Jquery: How to check if the element has certain css class/style

i've found one solution:


but somehow i believe that there's a better way!

SecurityError: Blocked a frame with origin from accessing a cross-origin frame

Check the domain's web server for http://www.<domain>.com configuration for X-Frame-Options It is a security feature designed to prevent clickJacking attacks,

How Does clickJacking work?

  1. The evil page looks exactly like the victim page.
  2. Then it tricked users to enter their username and password.

Technically the evil has an iframe with the source to the victim page.

    <iframe src=''/>
    <input id="username" type="text" style="display: none;"/>
    <input id="password" type="text" style="display: none;"/>
        //some JS code that click jacking the user username and input from inside the iframe...

How the security feature work

If you want to prevent web server request to be rendered within an iframe add the x-frame-options

X-Frame-Options DENY

The options are:

  1. SAMEORIGIN //allow only to my own domain render my HTML inside an iframe.
  2. DENY //do not allow my HTML to be rendered inside any iframe
  3. "ALLOW-FROM" //allow specific domain to render my HTML inside an iframe

This is IIS config example:

           <add name="X-Frame-Options" value="SAMEORIGIN" />

The solution to the question

If the web server activated the security feature it may cause a client-side SecurityError as it should.

How to Execute SQL Server Stored Procedure in SQL Developer?

You need to do this:

    exec procName 
    @parameter_1_Name = 'parameter_1_Value', 
    @parameter_2_name = 'parameter_2_value',
    @parameter_z_name = 'parameter_z_value'

How would I get a cron job to run every 30 minutes?

You can use both of ',' OR divide '/' symbols.
But, '/' is better.
Suppose the case of 'every 5 minutes'. If you use ',', you have to write the cron job as following:

0,5,10,15,20,25,30,35,....    *      *     *   * your_command

It means run your_command in every hour in all of defined minutes: 0,5,10,...

However, if you use '/', you can write the following simple and short job:

*/5  *  *  *  *  your_command

It means run your_command in the minutes that are dividable by 5 or in the simpler words, '0,5,10,...'

So, dividable symbol '/' is the best choice always;

How to check Oracle database for long running queries

You can generate an AWR (automatic workload repository) report from the database.

Run from the SQL*Plus command line:

SQL> @$ORACLE_HOME/rdbms/admin/awrrpt.sql

Read the document related to how to generate & understand an AWR report. It will give a complete view of database performance and resource issues. Once we are familiar with the AWR report it will be helpful to find Top SQL which is consuming resources.

Also, in the 12C EM Express UI we can generate an AWR.

Start thread with member function

Since you are using C++11, lambda-expression is a nice&clean solution.

class blub {
    void test() {}
    std::thread spawn() {
      return std::thread( [this] { this->test(); } );

since this-> can be omitted, it could be shorten to:

std::thread( [this] { test(); } )

or just (deprecated)

std::thread( [=] { test(); } )

How can I preview a merge in git?

Adding to the existing answers, an alias could be created to show the diff and/or log prior to a merge. Many answers omit the fetch to be done first before "previewing" the merge; this is an alias that combines these two steps into one (emulating something similar to mercurial's hg incoming / outgoing)

So, building on "git log ..otherbranch", you can add the following to ~/.gitconfig :

    # fetch and show what would be merged (use option "-p" to see patch)
    incoming = "!git remote update -p; git log ..@{u}"

For symmetry, the following alias can be used to show what is committed and would be pushed, prior to pushing:

    # what would be pushed (currently committed)
    outgoing = log @{u}..

And then you can run "git incoming" to show a lot of changes, or "git incoming -p" to show the patch (i.e., the "diff"), "git incoming --pretty=oneline", for a terse summary, etc. You may then (optionally) run "git pull" to actually merge. (Though, since you've already fetched, the merge could be done directly.)

Likewise, "git outgoing" shows what would be pushed if you were to run "git push".

Why I am getting Cannot pass parameter 2 by reference error when I am using bindParam with a constant value?

In my case I am using:

  • SQLite,

  • prepared statements with placeholders to handle unknown number of fields,

  • AJAX request sent by user where everything is a string and there is no such thing like NULL value and

  • I desperately need to insert NULLs as that does not violates foreign key constrains (acceptable value).

Suppose, now user sends with post: $_POST[field1] with value value1 which can be the empty string "" or "null" or "NULL".

First I make the statement:

$stmt = $this->dbh->prepare("INSERT INTO $table ({$sColumns}) VALUES ({$sValues})");

where {$sColumns} is sth like field1, field2, ... and {$sValues} are my placeholders ?, ?, ....

Then, I collect my $_POST data related with the column names in an array $values and replace with NULLs:

  for($i = 0; $i < \count($values); $i++)
     if((\strtolower($values[$i]) == 'null') || ($values[$i] == ''))
        $values[$i] = null;

Now, I can execute:


and among other bypass foreign key constrains.

If on the other hand, an empty string does makes more sense then you have to check if that field is part of a foreign key or not (more complicated).

Using "like" wildcard in prepared statement

Code it like this:

PreparedStatement pstmt = con.prepareStatement(
    "SELECT * FROM analysis WHERE notes like ?");
pstmt.setString(1, notes + "%");`

Make sure that you DO NOT include the quotes ' ' like below as they will cause an exception.

pstmt.setString(1,"'%"+ notes + "%'");

Datatable vs Dataset

When you are only dealing with a single table anyway, the biggest practical difference I have found is that DataSet has a "HasChanges" method but DataTable does not. Both have a "GetChanges" however, so you can use that and test for null.

Beginner Python: AttributeError: 'list' object has no attribute


class Bike(object):
    def __init__(self, name, weight, cost): = name
        self.weight = weight
        self.cost = cost

bikes = {
    # Bike designed for children"
    "Trike": Bike("Trike", 20, 100),      # <--
    # Bike designed for everyone"
    "Kruzer": Bike("Kruzer", 50, 165),    # <--

# Markup of 20% on all sales
margin = .2
# Revenue minus cost after sale
for bike in bikes.values():
    profit = bike.cost * margin



The difference is that in your bikes dictionary, you're initializing the values as lists [...]. Instead, it looks like the rest of your code wants Bike instances. So create Bike instances: Bike(...).

As for your error

AttributeError: 'list' object has no attribute 'cost'

this will occur when you try to call .cost on a list object. Pretty straightforward, but we can figure out what happened by looking at where you call .cost -- in this line:

profit = bike.cost * margin

This indicates that at least one bike (that is, a member of bikes.values() is a list). If you look at where you defined bikes you can see that the values were, in fact, lists. So this error makes sense.

But since your class has a cost attribute, it looked like you were trying to use Bike instances as values, so I made that little change:

[...] -> Bike(...)

and you're all set.

Using "If cell contains #N/A" as a formula condition.

Input the following formula in C1:



When #N/A:

enter image description here

When not #N/A:

enter image description here

Let us know if this helps.

How to calculate difference in hours (decimal) between two dates in SQL Server?

Using Postgres I had issues with DATEDIFF, but had success with this:

  DATE_PART('day',(delivery_time)::timestamp - (placed_time)::timestamp) * 24 + 
  DATE_PART('hour',(delivery_time)::timestamp - (placed_time)::timestamp) +
  DATE_PART('minute',(delivery_time)::timestamp - (placed_time)::timestamp) / 60

which gave me an output like "14.3"

Printing string variable in Java

You're getting the toString() value returned by the Scanner object itself which is not what you want and not how you use a Scanner object. What you want instead is the data obtained by the Scanner object. For example,

Scanner input = new Scanner(;
String data = input.nextLine();

Please read the tutorial on how to use it as it will explain all.

Please look here: Scanner tutorial

Also have a look at the Scanner API which will explain some of the finer points of Scanner's methods and properties.

Find the division remainder of a number

We can solve this by using modulus operator (%)

26 % 7 = 5;

but 26 / 7 = 3 because it will give quotient but % operator will give remainder.

How to output a comma delimited list in jinja python template?

you could also use the builtin "join" filter ( like this:

{{ users|join(', ') }}

CSS3 transform: rotate; in IE9

I know this is old, but I was having this same issue, found this post, and while it didn't explain exactly what was wrong, it helped me to the right answer - so hopefully my answer helps someone else who might be having a similar problem to mine.

I had an element I wanted rotated vertical, so naturally I added the filter: for IE8 and then the -ms-transform property for IE9. What I found is that having the -ms-transform property AND the filter applied to the same element causes IE9 to render the element very poorly. My solution:

  1. If you are using the transform-origin property, add one for MS too (-ms-transform-origin: left bottom;). If you don't see your element, it could be that it's rotating on it's middle axis and thus leaving the page somehow - so double check that.

  2. Move the filter: property for IE7&8 to a separate style sheet and use an IE conditional to insert that style sheet for browsers less than IE9. This way it doesn't affect the IE9 styles and all should work fine.

  3. Make sure to use the correct DOCTYPE tag as well; if you have it wrong IE9 will not work properly.

AngularJS - Binding radio buttons to models with boolean values

The way your radios are set up in the fiddle - sharing the same model - will cause only the last group to show a checked radio if you decide to quote all of the truthy values. A more solid approach will involve giving the individual groups their own model, and set the value as a unique attribute of the radios, such as the id:

$scope.radioMod = 1;
$scope.radioMod2 = 2;

Here is a representation of the new html:

<label data-ng-repeat="choice2 in question2.choices">
            <input type="radio" name="response2" data-ng-model="radioMod2" value="{{}}"/>

And a fiddle.

Check whether user has a Chrome extension installed

Chrome now has the ability to send messages from the website to the extension.

So in the extension background.js (content.js will not work) add something like:

    function(request, sender, sendResponse) {
        if (request) {
            if (request.message) {
                if (request.message == "version") {
                    sendResponse({version: 1.0});
        return true;

This will then let you make a call from the website:

var hasExtension = false;

chrome.runtime.sendMessage(extensionId, { message: "version" },
    function (reply) {
        if (reply) {
            if (reply.version) {
                if (reply.version >= requiredVersion) {
                    hasExtension = true;
        else {
          hasExtension = false;

You can then check the hasExtension variable. The only drawback is the call is asynchronous, so you have to work around that somehow.

Edit: As mentioned below, you'll need to add an entry to the manifest.json listing the domains that can message your addon. Eg:

"externally_connectable": {
    "matches": ["*://localhost/*", "*://*"]

How can I tell which button was clicked in a PHP form submit?

All you need to give the name attribute to the each button. And you need to address each button press from the PHP script. But be careful to give each button a unique name. Because the PHP script only take care of the name most of the time

<input type="submit" name="Submit_this" id="This" />

Prevent text selection after double click

function clearSelection() {
    if(document.selection && document.selection.empty) {
    } else if(window.getSelection) {
        var sel = window.getSelection();

You can also apply these styles to the span for all non-IE browsers and IE10:

span.no_selection {
    user-select: none; /* standard syntax */
    -webkit-user-select: none; /* webkit (safari, chrome) browsers */
    -moz-user-select: none; /* mozilla browsers */
    -khtml-user-select: none; /* webkit (konqueror) browsers */
    -ms-user-select: none; /* IE10+ */

plot is not defined

If you want to use a function form a package or module in python you have to import and reference them. For example normally you do the following to draw 5 points( [1,5],[2,4],[3,3],[4,2],[5,1]) in the space:

import matplotlib.pyplot

In your solution

from matplotlib import*

This imports the package matplotlib and "plot is not defined" means there is no plot function in matplotlib you can access directly, but instead if you import as

from matplotlib.pyplot import *

Now you can use any function in matplotlib.pyplot without referencing them with matplotlib.pyplot.

I would recommend you to name imports you have, in this case you can prevent disambiguation and future problems with the same function names. The last and clean version of above example looks like:

import matplotlib.pyplot as plt

Java : Sort integer array without using Arrays.sort()

int x[] = { 10, 30, 15, 69, 52, 89, 5 };
    int max, temp = 0, index = 0;
    for (int i = 0; i < x.length; i++) {
        int counter = 0;
        max = x[i];
        for (int j = i + 1; j < x.length; j++) {

            if (x[j] > max) {
                max = x[j];
                index = j;

        if (counter > 0) {
            temp = x[index];
            x[index] = x[i];
            x[i] = temp;
    for (int i = 0; i < x.length; i++) {

I want to delete all bin and obj folders to force all projects to rebuild everything

Is 'clean' not good enough? Note that you can call msbuild with /t:clean from the command-line.

Problem with SMTP authentication in PHP using PHPMailer, with Pear Mail works

Check if you have set restrict outgoing SMTP to only some system users (root, MTA, mailman...). That restriction may prevent the spammers, but will redirect outgoing SMTP connections to the local mail server.

Bash scripting, multiple conditions in while loop


while [ $stats -gt 300 -o $stats -eq 0 ]

[ is a call to test. It is not just for grouping, like parentheses in other languages. Check man [ or man test for more information.

Regex for not empty and not whitespace

/^$|\s+/ if this matched, there's whitespace or its empty.

How to have comments in IntelliSense for function in Visual Studio?

Those are called XML Comments. They have been a part of Visual Studio since forever.

You can make your documentation process easier by using GhostDoc, a free add-in for Visual Studio which generates XML-doc comments for you. Just place your caret on the method/property you want to document, and press Ctrl-Shift-D.

Here's an example from one of my posts.

Hope that helps :)

get UTC timestamp in python with datetime

If input datetime object is in UTC:

>>> dt = datetime(2008, 1, 1, 0, 0, 0, 0)
>>> timestamp = (dt - datetime(1970, 1, 1)).total_seconds()

Note: it returns float i.e., microseconds are represented as fractions of a second.

If input date object is in UTC:

>>> from datetime import date
>>> utc_date = date(2008, 1, 1)
>>> timestamp = (utc_date.toordinal() - date(1970, 1, 1).toordinal()) * 24*60*60

See more details at Converting to UTC timestamp in Python.

How to move an entire div element up x pixels?

you can also do this


this "help" to stop the div yanking everything up a bit.

Shell script "for" loop syntax

If the seq command available on your system:

for i in `seq 2 $max`
  echo "output: $i"

If not, then use poor man's seq with perl:

seq=`perl -e "\$,=' ';print 2..$max"`
for i in $seq
  echo "output: $i"

Watch those quote marks.

Django URLs TypeError: view must be a callable or a list/tuple in the case of include()

Your code is

urlpatterns = [
    url(r'^$', 'myapp.views.home'),
    url(r'^contact/$', ''),
    url(r'^login/$', 'django.contrib.auth.views.login'),

change it to following as you're importing include() function :

urlpatterns = [
    url(r'^$', views.home),
    url(r'^login/$', views.login),

JQuery Bootstrap Multiselect plugin - Set a value as selected in the multiselect dropdown

var valArr = [101,102], // array of option values
    i = 0, size = valArr.length, // index and array size declared here to avoid overhead
    $options = $('#data option'); // options cached here to avoid overhead of fetching inside loop

// run the loop only for the given values
for(i; i < size; i++){
    // filter the options with the specific value and select them
    $options.filter('[value="'+valArr[i]+'"]').prop('selected', true);

Here is a demo

Conversion between UTF-8 ArrayBuffer and String

The main problem of programmers looking for conversion from byte array into a string is UTF-8 encoding (compression) of unicode characters. This code will help you:

var getString = function (strBytes) {

    var MAX_SIZE = 0x4000;
    var codeUnits = [];
    var highSurrogate;
    var lowSurrogate;
    var index = -1;

    var result = '';

    while (++index < strBytes.length) {
        var codePoint = Number(strBytes[index]);

        if (codePoint === (codePoint & 0x7F)) {

        } else if (0xF0 === (codePoint & 0xF0)) {
            codePoint ^= 0xF0;
            codePoint = (codePoint << 6) | (strBytes[++index] ^ 0x80);
            codePoint = (codePoint << 6) | (strBytes[++index] ^ 0x80);
            codePoint = (codePoint << 6) | (strBytes[++index] ^ 0x80);
        } else if (0xE0 === (codePoint & 0xE0)) {
            codePoint ^= 0xE0;
            codePoint = (codePoint << 6) | (strBytes[++index] ^ 0x80);
            codePoint = (codePoint << 6) | (strBytes[++index] ^ 0x80);
        } else if (0xC0 === (codePoint & 0xC0)) {
            codePoint ^= 0xC0;
            codePoint = (codePoint << 6) | (strBytes[++index] ^ 0x80);

        if (!isFinite(codePoint) || codePoint < 0 || codePoint > 0x10FFFF || Math.floor(codePoint) != codePoint)
            throw RangeError('Invalid code point: ' + codePoint);

        if (codePoint <= 0xFFFF)
        else {
            codePoint -= 0x10000;
            highSurrogate = (codePoint >> 10) | 0xD800;
            lowSurrogate = (codePoint % 0x400) | 0xDC00;
            codeUnits.push(highSurrogate, lowSurrogate);
        if (index + 1 == strBytes.length || codeUnits.length > MAX_SIZE) {
            result += String.fromCharCode.apply(null, codeUnits);
            codeUnits.length = 0;

    return result;

All the best !

What to gitignore from the .idea folder?

  • Remove .idea folder

    $rm -R .idea/
  • Add rule

    $echo ".idea/*" >> .gitignore
  • Commit .gitignore file

    $git commit -am "remove .idea"
  • Next commit will be ok

How to upload & Save Files with Desired name

Here is the code in PHP to upload an image, save it to the database, display it and save it to a folder.

  1. At first, HTML code for the form:

    <div class="upload">
        <form method="POST" enctype="multipart/form-data" id="imageform">
           <input type="file" name="image" id="photoimg" >
           <input type="submit" name="submit" value="UPLOAD">
  2. The PHP code

create database and table as you wish.(only required 2 fields) In the table, id(INT) 255 primary key AUTO INCREMENT and your image row(anyname) (MEDIUMBLOB)


    if(@getimagesize($_FILES['image']['tmp_name']) == FALSE){
        echo "<span class='image_select'>please select an image</span>";

        $image = addslashes($_FILES['image']['tmp_name']);
        $name  = addslashes($_FILES['image']['name']);
        $image = file_get_contents($image);
        $image = base64_encode($image);
        $uploaddir = 'profile/'; //this is your local directory
        $uploadfile = $uploaddir . basename($_FILES['image']['name']);

        echo "<p>";

            if (move_uploaded_file($_FILES['image']['tmp_name'], $uploadfile)) {// file uploaded and moved} 
            else { //uploaded but not moved}

        echo "</p>";



function saveimage($name,$image)
    $con = mysql_connect("localhost","root","your database password");
    mysql_select_db("your database",$con);
    $qry  = "UPDATE your_table SET your_row_name='$image'";
        $result = @mysql_query($qry,$con);

        echo "<span class='uploaded'>IMAGE UPLOADED</span>";

        echo "<span class='upload_failed'>IMAGE NOT UPLOADED</span>";

function displayimage()
    $con = mysql_connect("localhost","root","your_password");
    $qry  = "select * from your_table";
    $result = mysql_query($qry,$con);

    while($row  = mysql_fetch_array($result))
        echo '<img class="image" src="data:image;base64,'.$row[1].'">';




SELECT * FROM employees WHERE name NOT IN (SELECT name FROM eotm_dyn)




SELECT * FROM employees LEFT OUTER JOIN eotm_dyn ON = WHERE eotm_dyn IS NULL

Default optional parameter in Swift function

in case you need to use a bool param, you need just to assign the default value.

func test(WithFlag flag: Bool = false){.....}

then you can use without or with the param:

test() //here flag automatically has the default value: false
test(WithFlag: true) //here flag has the value: true

Moment.js with ReactJS (ES6)

run npm i moment react-moment --save

you can use this in your component,

import Moment from 'react-moment';

const date = new Date();
<Moment format='MMMM Do YYYY, h:mm:ss a'>{date}</Moment>

will give you sth like this :
enter image description here

json_encode/json_decode - returns stdClass instead of Array in PHP

Take a closer look at the second parameter of json_decode($json, $assoc, $depth) at

Set IDENTITY_INSERT ON is not working

In VB code, when trying to submit an INSERT query, you must submit a double query in the same 'executenonquery' like this:

sqlQuery = "SET IDENTITY_INSERT dbo.TheTable ON; INSERT INTO dbo.TheTable (Col1, COl2) VALUES (Val1, Val2); SET IDENTITY_INSERT dbo.TheTable OFF;"

I used a ; separator instead of a GO.

Works for me. Late but efficient!

php check if array contains all array values from another array

The previous answers are all doing more work than they need to. Just use array_diff. This is the simplest way to do it:

$containsAllValues = !array_diff($search_this, $all);

That's all you have to do.

CertificateException: No name matching found

I've found a good resolution here:

But my problem was a little bit different and solved it differently.

The web service was on remote host. For example:

But it was available only by IP for any clients, but certificate was created for domain: ( And this domain can't be resolved by IP because it is not presented in DNS).

So the same problem appeared: if I use IP to connect to web service by ssl, it can't be reached becase certificate and it is not equal to host name I've specified (i.e. host IP).

I've resolved it by matching this hostname with IP in /etc/hosts file. The problem was fixed.

But in case when the Web Service is hosted on localhost app server, it think, it should be solved like mkyong described in his article.

Moment Js UTC to Local Time

I've created one function which converts all the timezones into local time.


1. npm i moment-timezone

function utcToLocal(utcdateTime, tz) {
    var zone ="Z") // Actual zone value e:g +5:30
    var zoneValue = zone.replace(/[^0-9: ]/g, "") // Zone value without + - chars
    var operator = zone && zone.split("") && zone.split("")[0] === "-" ? "-" : "+" // operator for addition subtraction
    var localDateTime
    var hours = zoneValue.split(":")[0]
    var minutes = zoneValue.split(":")[1]
    if (operator === "-") {
        localDateTime = moment(utcdateTime).subtract(hours, "hours").subtract(minutes, "minutes").format("YYYY-MM-DD HH:mm:ss")
    } else if (operator) {
        localDateTime = moment(utcdateTime).add(hours, "hours").add(minutes, "minutes").format("YYYY-MM-DD HH:mm:ss")
    } else {
        localDateTime = "Invalid Timezone Operator"
    return localDateTime

utcToLocal("2019-11-14 07:15:37", "Asia/Kolkata")

//Returns "2019-11-14 12:45:37"

Laravel Soft Delete posts

Just an update for Laravel 5:

In Laravel 4.2:

use Illuminate\Database\Eloquent\SoftDeletingTrait;    
class Post extends Eloquent {

    use SoftDeletingTrait;

    protected $dates = ['deleted_at'];


becomes in Laravel 5:

use Illuminate\Database\Eloquent\SoftDeletes;

class User extends Model {

    use SoftDeletes;
    protected $dates = ['deleted_at'];

ssh remote host identification has changed

I had this same error occur after I recreated a Digital Ocean Ubuntu image. I used the following command with my server IP in place of [IP_ADDRESS]

ssh-keygen -R [IP_ADDRESS]

How should you diagnose the error SEHException - External component has thrown an exception

Just another information... Had that problem today on a Windows 2012 R2 x64 TS system where the application was started from a unc/network path. The issue occured for one application for all terminal server users. Executing the application locally worked without problems. After a reboot it started working again - the SEHException's thrown had been Constructor init and TargetInvocationException

Adding up BigDecimals using Streams

Original answer

Yes, this is possible:

List<BigDecimal> bdList = new ArrayList<>();
//populate list
BigDecimal result =
        .reduce(BigDecimal.ZERO, BigDecimal::add);

What it does is:

  1. Obtain a List<BigDecimal>.
  2. Turn it into a Stream<BigDecimal>
  3. Call the reduce method.

    3.1. We supply an identity value for addition, namely BigDecimal.ZERO.

    3.2. We specify the BinaryOperator<BigDecimal>, which adds two BigDecimal's, via a method reference BigDecimal::add.

Updated answer, after edit

I see that you have added new data, therefore the new answer will become:

List<Invoice> invoiceList = new ArrayList<>();
Function<Invoice, BigDecimal> totalMapper = invoice -> invoice.getUnit_price().multiply(invoice.getQuantity());
BigDecimal result =
        .reduce(BigDecimal.ZERO, BigDecimal::add);

It is mostly the same, except that I have added a totalMapper variable, that has a function from Invoice to BigDecimal and returns the total price of that invoice.

Then I obtain a Stream<Invoice>, map it to a Stream<BigDecimal> and then reduce it to a BigDecimal.

Now, from an OOP design point I would advice you to also actually use the total() method, which you have already defined, then it even becomes easier:

List<Invoice> invoiceList = new ArrayList<>();
BigDecimal result =
        .reduce(BigDecimal.ZERO, BigDecimal::add);

Here we directly use the method reference in the map method.

How to reverse a 'rails generate'

Suppose I have created a controller named "sample" like:

rails generate controller sample

If I have to destroy this controller, all I have to do is swap generate with destroy, as in

rails destroy controller sample.

If you want to reverse the generation, all you have to do is swap generate with destroy.

Add a border outside of a UIView (instead of inside)

Unfortunately, there isn't simply a little property you can set to align the border to the outside. It draws aligned to the inside because the UIViews default drawing operations draw within its bounds.

The simplest solution that comes to mind would be to expand the UIView by the size of the border width when applying the border:

CGFloat borderWidth = 2.0f;

self.frame = CGRectInset(self.frame, -borderWidth, -borderWidth);
self.layer.borderColor = [UIColor yellowColor].CGColor;
self.layer.borderWidth = borderWidth;

jQuery click event not working after adding class

Based on @Arun P Johny this is how you do it for an input:

<input type="button" class="btEdit" id="myButton1">

This is how I got it in jQuery:

$(document).on('click', "input.btEdit", function () {
    var id =;

This will log on the console: myButton1. As @Arun said you need to add the event dinamically, but in my case you don't need to call the parent first.


Though it would be better to say:

$(document).on('click', "input.btEdit", function () {
    var id = $(this).id;

Since this is JQuery's syntax, even though both will work.

Cannot hide status bar in iOS7

For Swift 2.0+ IOS 9

override func prefersStatusBarHidden() -> Bool {
return true

Redirect after Login on WordPress

Please try this, it works for any redirection on WordPress

add_filter('woocommerce_login_redirect', 'wc_login_redirect'); 

function wc_login_redirect( $redirect_to ) {

   $redirect_to = 'PUT HERE URL OF THE PAGE';
   return $redirect_to;


How to write a basic swap function in Java

In cases like that there is a quick and dirty solution using arrays with one element:

public void swap(int[] a, int[] b) {
  int temp = a[0];
  a[0] = b[0];
  b[0] = temp;

Of course your code has to work with these arrays too, which is inconvenient. The array trick is more useful if you want to modify a local final variable from an inner class:

public void test() {
  final int[] a = int[]{ 42 };  
  new Thread(new Runnable(){ public void run(){ a[0] += 10; }}).start();
  while(a[0] == 42) {

Android : Check whether the phone is dual SIM

I was taking a look at the call logs and I noticed that apart from the usual fields in the contents of managedCursor, we have a column "simid" in Dual SIM phones (I checked on Xolo A500s Lite), so as to tag each call in the call log with a SIM. This value is either 1 or 2, most probably denoting SIM1/SIM2.

managedCursor = context.getContentResolver().query(contacts, null, null, null, null);
for(int i=0;i<managedCursor.getColumnCount();i++)
{//for dual sim phones

I did not find this column in a single SIM phone (I checked on Xperia L).

So although I don't think this is a foolproof way to check for dual SIM nature, I am posting it here because it could be useful to someone.

How to printf a 64-bit integer as hex?

Edit: Use printf("val = 0x%" PRIx64 "\n", val); instead.

Try printf("val = 0x%llx\n", val);. See the printf manpage:

ll (ell-ell). A following integer conversion corresponds to a long long int or unsigned long long int argument, or a following n conversion corresponds to a pointer to a long long int argument.

Edit: Even better is what @M_Oehm wrote: There is a specific macro for that, because unit64_t is not always a unsigned long long: PRIx64 see also this stackoverflow answer

Git Remote: Error: fatal: protocol error: bad line length character: Unab

I had same problem when I did git pull

git pull fatal: protocol error: bad line length character: <htm fatal: the remote end hung up unexpectedly

I changed my remote url HTTP to SSH, and it worked for me.

git remote set-url origin "HTTP" to "SSH"

Resolving ORA-4031 "unable to allocate x bytes of shared memory"


ORA-04031: unable to allocate 4064 bytes of shared memory ("shared pool","select increment$,minvalue,m...","sga heap(3,0)","kglsim heap")

Solution: by nepasoft nepal

  • 1.-

    ps -ef|grep oracle
  • 2.- Find the smon and kill the pid for it

  • 3.-

    SQL> startup mount
    ORACLE instance started.
    Total System Global Area 4831838208 bytes
    Fixed Size                  2027320 bytes
    Variable Size            4764729544 bytes
    Database Buffers           50331648 bytes
    Redo Buffers               14749696 bytes
    Database mounted.
  • 4.-

    SQL> alter system set shared_pool_size=100M scope=spfile;
    System altered.
  • 5.-

    SQL> shutdown immediate
    ORA-01109: database not open
    Database dismounted.
    ORACLE instance shut down.
  • 6.-

    SQL> startup
    ORACLE instance started.
    Total System Global Area 4831838208 bytes
    Fixed Size                  2027320 bytes
    Variable Size            4764729544 bytes
    Database Buffers           50331648 bytes
    Redo Buffers               14749696 bytes
    Database mounted.
    Database opened.
  • 7.-

    SQL> create pfile from spfile;
    File created.


How to show progress dialog in Android?

ProgressDialog pd = new ProgressDialog(yourActivity.this);;

How to pass a datetime parameter?

The problem is twofold:

1. The . in the route

By default, IIS treats all URI's with a dot in them as static resource, tries to return it and skip further processing (by Web API) altogether. This is configured in your Web.config in the section system.webServer.handlers: the default handler handles path="*.". You won't find much documentation regarding the strange syntax in this path attribute (regex would have made more sense), but what this apparently means is "anything that doesn't contain a dot" (and any character from point 2 below). Hence the 'Extensionless' in the name ExtensionlessUrlHandler-Integrated-4.0.

Multiple solutions are possible, in my opinion in the order of 'correctness':

  • Add a new handler specifically for the routes that must allow a dot. Be sure to add it before the default. To do this, make sure you remove the default handler first, and add it back after yours.
  • Change the path="*." attribute to path="*". It will then catch everything. Note that from then on, your web api will no longer interpret incoming calls with dots as static resources! If you are hosting static resources on your web api, this is therefor not advised!
  • Add the following to your Web.config to unconditionally handle all requests: under <system.webserver>: <modules runAllManagedModulesForAllRequests="true">

2. The : in the route

After you've changed the above, by default, you'd get the following error:

A potentially dangerous Request.Path value was detected from the client (:).

You can change the predefined disallowed/invalid characters in your Web.config. Under <system.web>, add the following: <httpRuntime requestPathInvalidCharacters="&lt;,&gt;,%,&amp;,*,\,?" />. I've removed the : from the standard list of invalid characters.

Easier/safer solutions

Although not an answer to your question, a safer and easier solution would be to change the request so that all this is not required. This can be done in two ways:

  1. Pass the date as a query string parameter, like ?date=2012-12-31T22:00:00.000Z.
  2. Strip the .000 from every request. You'd still need to allow :'s (cfr point 2).

How/When does Execute Shell mark a build as failure in Jenkins?

So by adding the #!/bin/sh will allow you to execute with no option.

It also helped me in fixing an issue where I was executing bash script from Jenkins master on my Linux slave. By just adding #!/bin/bash above my actual script in "Execute Shell" block it fixed my issue as otherwise it was executing windows git provided version of bash shell that was giving an error.

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

Simply install Win64 OpenSSL v1.0.2a or Win32 OpenSSL v1.0.2a, you can download these from Works out of the box, no configuration needed.

How to add more than one machine to the trusted hosts list using winrm

Same as @Altered-Ego but with txt.file:

Get-Content "C:\ServerList.txt"

$ServerList = Get-Content "C:\ServerList.txt"
    $currentTrustHost=(get-item WSMan:\localhost\Client\TrustedHosts).value
    if ( ($currentTrustHost).Length -gt "0" ) {
        $currentTrustHost+= ,$ServerList
        set-item WSMan:\localhost\Client\TrustedHosts –value $currentTrustHost -Force -ErrorAction SilentlyContinue
    else {
        $currentTrustHost+= $ServerList
        set-item WSMan:\localhost\Client\TrustedHosts –value $currentTrustHost -Force -ErrorAction SilentlyContinue

The "-ErrorAction SilentlyContinue" is required in old PS version to avoid fake error message:

PS C:\Windows\system32> get-item WSMan:\localhost\Client\TrustedHosts

   WSManConfig: Microsoft.WSMan.Management\WSMan::localhost\Client

Type            Name                           SourceOfValue   Value
----            ----                           -------------   -----
System.String   TrustedHosts                                   machineA,machineB,machineC,machineD

when exactly are we supposed to use "public static final String"?

? public makes it accessible across the other classes. You can use it without instantiate of the class or using any object.

? static makes it uniform value across all the class instances. It ensures that you don't waste memory creating many of the same thing if it will be the same value for all the objects.

? final makes it non-modifiable value. It's a "constant" value which is same across all the class instances and cannot be modified.

How can I create Min stl priority_queue?

In C++11 you could also create an alias for convenience:

template<class T> using min_heap = priority_queue<T, std::vector<T>, std::greater<T>>;

And use it like this:

min_heap<int> my_heap;

how to fix Cannot call sendRedirect() after the response has been committed?

you have already forwarded the response in catch block:

RequestDispatcher dd = request.getRequestDispatcher("error.jsp");

dd.forward(request, response);

so, you can not again call the :


because it is already forwarded (committed).

So what you can do is: keep a string to assign where you need to forward the response.

    String page = "";
    try {

    } catch (Exception e) {
      page = "error.jsp";
    } finally {
      page = "usertaskpage.jsp";

RequestDispatcher dd=request.getRequestDispatcher(page);
dd.forward(request, response);

Fastest way to determine if an integer's square root is an integer

You'll have to do some benchmarking. The best algorithm will depend on the distribution of your inputs.

Your algorithm may be nearly optimal, but you might want to do a quick check to rule out some possibilities before calling your square root routine. For example, look at the last digit of your number in hex by doing a bit-wise "and." Perfect squares can only end in 0, 1, 4, or 9 in base 16, So for 75% of your inputs (assuming they are uniformly distributed) you can avoid a call to the square root in exchange for some very fast bit twiddling.

Kip benchmarked the following code implementing the hex trick. When testing numbers 1 through 100,000,000, this code ran twice as fast as the original.

public final static boolean isPerfectSquare(long n)
    if (n < 0)
        return false;

    switch((int)(n & 0xF))
    case 0: case 1: case 4: case 9:
        long tst = (long)Math.sqrt(n);
        return tst*tst == n;

        return false;

When I tested the analogous code in C++, it actually ran slower than the original. However, when I eliminated the switch statement, the hex trick once again make the code twice as fast.

int isPerfectSquare(int n)
    int h = n & 0xF;  // h is the last hex "digit"
    if (h > 9)
        return 0;
    // Use lazy evaluation to jump out of the if statement as soon as possible
    if (h != 2 && h != 3 && h != 5 && h != 6 && h != 7 && h != 8)
        int t = (int) floor( sqrt((double) n) + 0.5 );
        return t*t == n;
    return 0;

Eliminating the switch statement had little effect on the C# code.

How to replace a string in multiple files in linux command line

script for multiedit command


From Kaspar's answer I made a bash script to accept command line arguments and optionally limit the filenames matching a pattern. Save in your $PATH and make executable, then just use the command above.

Here's the script:

Replace OLDSTRING with NEWSTRING recursively starting from current directory\n

[-n PATTERN] option limits to filenames matching PATTERN\n
Note: backslash escape special characters\n
Note: enclose STRINGS with spaces in double quotes\n
Example to limit the edit to python files:\n
multiedit -n \*.py \"OLD STRING\" NEWSTRING\n"

# ensure correct number of arguments, otherwise display help...
if [ $# -lt 2 ] || [ $# -gt 4 ]; then echo -e $_help ; exit ; fi
if [ $1 == "-n" ]; then  # if -n option is given:
        # replace OLDSTRING with NEWSTRING recursively in files matching PATTERN
        find ./ -type f -name "$2" -exec sed -i "s/$3/$4/g" {} \;
        # replace OLDSTRING with NEWSTRING recursively in all files
        find ./ -type f -exec sed -i "s/$1/$2/" {} \;

How do I delete multiple rows with different IDs?

Delete from BA_CITY_MASTER where CITY_NAME in (select CITY_NAME from BA_CITY_MASTER group by CITY_NAME having count(CITY_NAME)>1);

<button> background image

For some odd reason, the width and height of the button have been reset. You need to specify them in the ID selector as well:

#rock {
    width: 150px;
    height: 150px;
    background-image: url(;
    background-repeat: no-repeat;

Live test case.

window.location (JS) vs header() (PHP) for redirection

It depends on how and when you want to redirect the user to another page.

If you want to instantly redirect a user to another page without him seeing anything of a site in between, you should use the PHP header redirect method.

If you have a Javascript and some action of the user has to result in him entering another page, that is when you should use window.location.

The meta tag refresh is often used on download sites whenever you see these "Your download should start automatically" messages. You can let the user load a page, wait for a certain amount of time, then redirect him (e.g. to a to-be-downloaded file) without Javascript.

Convert base64 png data to javascript file objects

Way 1: only works for dataURL, not for other types of url.

function dataURLtoFile(dataurl, filename) {
    var arr = dataurl.split(','), mime = arr[0].match(/:(.*?);/)[1],
        bstr = atob(arr[1]), n = bstr.length, u8arr = new Uint8Array(n);
        u8arr[n] = bstr.charCodeAt(n);
    return new File([u8arr], filename, {type:mime});

//Usage example:
var file = dataURLtoFile('data:image/png;base64,......', 'a.png');

Way 2: works for any type of url, (http url, dataURL, blobURL, etc...)

//return a promise that resolves with a File instance
function urltoFile(url, filename, mimeType){
    mimeType = mimeType || (url.match(/^data:([^;]+);/)||'')[1];
    return (fetch(url)
        .then(function(res){return res.arrayBuffer();})
        .then(function(buf){return new File([buf], filename, {type:mimeType});})

//Usage example:
urltoFile('data:image/png;base64,......', 'a.png')

Both works in Chrome and Firefox.

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

I imported new colors to my project and got the same problem. So I opened styles.xml and re-assigned items to colors using new colors names.

including parameters in OPENQUERY

Just try it this way, should work, easy! In your WHERE clause, after column name and equal to sign:- add TWO single quotes, your search value and then THREE single quotes. Close the bracket.


Eclipse : Maven search dependencies doesn't work

Eclipse artifact searching depends on repository's index file. It seems you did not download the index file.

Go to Window -> Prefrences -> Maven and check "Download repository index updates on start". Restart Eclipse and then look at the progress view. An index file should be downloading.

After downloading completely, artifact searching will be ready to use.

Maven Settings

UPDATE You also need to rebuild your Maven repository index in 'maven repository view'.

In this view , open 'Global Repositories', right-click 'central', check 'Full Index Enable', and then, click 'Rebuild Index' in the same menu.

A 66M index file will be downloaded.

Maven Repositories -> Rebuild Index

Convert datetime object to a String of date only in Python

If you want the time as well, just go with

Prints 2019-07-11 19:36:31.118766 in console for me

Node.js – events js 72 throw er unhandled 'error' event

Close nodejs app running in another shell. Restart the terminal and run the program again.

Another server might be also using the same port that you have used for nodejs. Kill the process that is using nodejs port and run the app.

To find the PID of the application that is using port:8000

$ fuser 8000/tcp
8000/tcp:            16708

Here PID is 16708 Now kill the process using the kill [PID] command

$ kill 16708

Two Radio Buttons ASP.NET C#

Make sure their GroupName properties are set to the same name:

<asp:RadioButton GroupName="MeasurementSystem" runat="server" Text="US" />
<asp:RadioButton GroupName="MeasurementSystem" runat="server" Text="Metric" />

Creating an instance using the class name and calling constructor

Very Simple way to create an object in Java using Class<?> with constructor argument(s) passing:

Case 1:- Here, is a small code in this Main class:

import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;

public class Main {

    public static void main(String args[]) throws ClassNotFoundException, NoSuchMethodException, SecurityException, InstantiationException, IllegalAccessException, IllegalArgumentException, InvocationTargetException {

        // Get class name as string.
        String myClassName = Base.class.getName();
        // Create class of type Base.
        Class<?> myClass = Class.forName(myClassName);
        // Create constructor call with argument types.
        Constructor<?> ctr = myClass.getConstructor(String.class);
        // Finally create object of type Base and pass data to constructor.
        String arg1 = "My User Data";
        Object object = ctr.newInstance(new Object[] { arg1 });
        // Type-cast and access the data from class Base.
        Base base = (Base)object;


And, here is the Base class structure:

public class Base {

    public String data = null;

    public Base() 
        data = "default";

    public Base(String arg1) {
        data = arg1;


Case 2:- You, can code similarly for constructor with multiple argument and copy constructor. For example, passing 3 arguments as parameter to the Base constructor will need the constructor to be created in class and a code change in above as:

Constructor<?> ctr = myClass.getConstructor(String.class, String.class, String.class);
Object object = ctr.newInstance(new Object[] { "Arg1", "Arg2", "Arg3" }); 

And here the Base class should somehow look like:

public class Base {

    public Base(String a, String b, String c){
        // This constructor need to be created in this case.

Note:- Don't forget to handle the various exceptions which need to be handled in the code.

Running Node.js in apache?

While doing my own server side JS experimentation I ended up using teajs. It conforms to common.js, is based on V8 AND is the only project that I know of that provides 'mod_teajs' apache server module.

In my opinion Node.js server is not production ready and lacks too many features - Apache is battle tested and the right way to do SSJS.

print arraylist element?

If you want to print an arraylist with integer numbers, as an example you can use below code.

class Test{
    public static void main(String[] args){
        ArrayList<Integer> arraylist = new ArrayList<Integer>();

        for(int i=0; i<=10; i++){
            arraylist .add(i);
       for (Integer n : arraylist ){

The output is above code:


How to convert .pfx file to keystore with private key?

Using JDK 1.6 or later

It has been pointed out by Justin in the comments below that keytool alone is capable of doing this using the following command (although only in JDK 1.6 and later):

keytool -importkeystore -srckeystore mypfxfile.pfx -srcstoretype pkcs12 
-destkeystore clientcert.jks -deststoretype JKS

Using JDK 1.5 or below

OpenSSL can do it all. This answer on JGuru is the best method that I've found so far.

Firstly make sure that you have OpenSSL installed. Many operating systems already have it installed as I found with Mac OS X.

The following two commands convert the pfx file to a format that can be opened as a Java PKCS12 key store:

openssl pkcs12 -in mypfxfile.pfx -out mypemfile.pem
openssl pkcs12 -export -in mypemfile.pem -out mykeystore.p12 -name "MyCert"

NOTE that the name provided in the second command is the alias of your key in the new key store.

You can verify the contents of the key store using the Java keytool utility with the following command:

keytool -v -list -keystore mykeystore.p12 -storetype pkcs12

Finally if you need to you can convert this to a JKS key store by importing the key store created above into a new key store:

keytool -importkeystore -srckeystore mykeystore.p12 -destkeystore clientcert.jks -srcstoretype pkcs12 -deststoretype JKS

How to connect html pages to mysql database?

HTML are markup languages, basically they are set of tags like <html>, <body>, which is used to present a website using , and as a whole. All these, happen in the clients system or the user you will be browsing the website.

Now, Connecting to a database, happens on whole another level. It happens on server, which is where the website is hosted.

So, in order to connect to the database and perform various data related actions, you have to use server-side scripts, like , , etc.

Now, lets see a snippet of connection using MYSQLi Extension of PHP

$db = mysqli_connect('hostname','username','password','databasename');

This single line code, is enough to get you started, you can mix such code, combined with HTML tags to create a HTML page, which is show data based pages. For example:

    $db = mysqli_connect('hostname','username','password','databasename');
                $query = "SELECT * FROM `mytable`;";
                $result = mysqli_query($db, $query);
                while($row = mysqli_fetch_assoc($result)) {
                      // Display your datas on the page

In order to insert new data into the database, you can use phpMyAdmin or write a INSERT query and execute them.

How to check if a function exists on a SQL database

This is what SSMS uses when you script using the DROP and CREATE option

           FROM   sys.objects
           WHERE  object_id = OBJECT_ID(N'[dbo].[foo]')
                  AND type IN ( N'FN', N'IF', N'TF', N'FS', N'FT' ))
  DROP FUNCTION [dbo].[foo]


This approach to deploying changes means that you need to recreate all permissions on the object so you might consider ALTER-ing if Exists instead.

Open File Dialog, One Filter for Multiple Excel Extensions?

If you want to merge the filters (eg. CSV and Excel files), use this formula:

OpenFileDialog of = new OpenFileDialog();
of.Filter = "CSV files (*.csv)|*.csv|Excel Files|*.xls;*.xlsx";

Or if you want to see XML or PDF files in one time use this:

of.Filter = @" XML or PDF |*.xml;*.pdf";

Notepad++: Multiple words search in a file (may be in different lines)?

If you are using Notepad++ editor (like the tag of the question suggests), you can use the great "Find in Files" functionality.

Go to SearchFind in Files (Ctrl+Shift+F for the keyboard addicted) and enter:

  • Find What = (cat|town)

  • Filters = *.txt

  • Directory = enter the path of the directory you want to search in. You can check Follow current doc. to have the path of the current file to be filled.

  • Search mode = Regular Expression

How to get text of an input text box during onKeyPress?

Try to concatenate the event charCode to the value you get. Here is a sample of my code:

<input type="text" name="price" onkeypress="return (cnum(event,this))" maxlength="10">
<p id="demo"></p>


function cnum(event, str) {
    var a = event.charCode;
    var ab = str.value + String.fromCharCode(a);
    document.getElementById('demo').innerHTML = ab;

The value in ab will get the latest value in the input field.

Python: Append item to list N times

For immutable data types:

l = [0] * 100
# [0, 0, 0, 0, 0, ...]

l = ['foo'] * 100
# ['foo', 'foo', 'foo', 'foo', ...]

For values that are stored by reference and you may wish to modify later (like sub-lists, or dicts):

l = [{} for x in range(100)]

(The reason why the first method is only a good idea for constant values, like ints or strings, is because only a shallow copy is does when using the <list>*<number> syntax, and thus if you did something like [{}]*100, you'd end up with 100 references to the same dictionary - so changing one of them would change them all. Since ints and strings are immutable, this isn't a problem for them.)

If you want to add to an existing list, you can use the extend() method of that list (in conjunction with the generation of a list of things to add via the above techniques):

a = [1,2,3]
b = [4,5,6]
# a is now [1,2,3,4,5,6]

Sum rows in data.frame or matrix

The rowSums function (as Greg mentions) will do what you want, but you are mixing subsetting techniques in your answer, do not use "$" when using "[]", your code should look something more like:

data$new <- rowSums( data[,43:167] )

If you want to use a function other than sum, then look at ?apply for applying general functions accross rows or columns.

How do I pass multiple parameters into a function in PowerShell?

If you try:

PS > Test("ABC", "GHI") ("DEF")

you get:

$arg1 value: ABC GHI
$arg2 value: DEF

So you see that the parentheses separates the parameters

If you try:

PS > $var = "C"
PS > Test ("AB" + $var) "DEF"

you get:

$arg1 value: ABC
$arg2 value: DEF

Now you could find some immediate usefulness of the parentheses - a space will not become a separator for the next parameter - instead you have an eval function.

What is the T-SQL syntax to connect to another SQL Server?

If possible, check out SSIS (SQL Server Integration Services). I am just getting my feet wet with this toolkit, but already am looping over 40+ servers and preparing to wreak all kinds of havoc ;)

Type converting slices of interfaces

In Go, there is a general rule that syntax should not hide complex/costly operations. Converting a string to an interface{} is done in O(1) time. Converting a []string to an interface{} is also done in O(1) time since a slice is still one value. However, converting a []string to an []interface{} is O(n) time because each element of the slice must be converted to an interface{}.

The one exception to this rule is converting strings. When converting a string to and from a []byte or a []rune, Go does O(n) work even though conversions are "syntax".

There is no standard library function that will do this conversion for you. You could make one with reflect, but it would be slower than the three line option.

Example with reflection:

func InterfaceSlice(slice interface{}) []interface{} {
    s := reflect.ValueOf(slice)
    if s.Kind() != reflect.Slice {
        panic("InterfaceSlice() given a non-slice type")

    // Keep the distinction between nil and empty slice input
    if s.IsNil() {
        return nil

    ret := make([]interface{}, s.Len())

    for i:=0; i<s.Len(); i++ {
        ret[i] = s.Index(i).Interface()

    return ret

Your best option though is just to use the lines of code you gave in your question:

b := make([]interface{}, len(a))
for i := range a {
    b[i] = a[i]

Single Form Hide on Startup

You're going to want to set the window state to minimized, and show in taskbar to false. Then at the end of your forms Load set window state to maximized and show in taskbar to true

    public frmMain()
        Program.MainForm = this;

        this.WindowState = FormWindowState.Minimized;
        this.ShowInTaskbar = false;

private void frmMain_Load(object sender, EventArgs e)
        //Do heavy things here

        //At the end do this
        this.WindowState = FormWindowState.Maximized;
        this.ShowInTaskbar = true;

React: trigger onChange if input value is changing by state?

The other answers talked about direct binding in render hence I want to add few points regarding that.

You are not recommended to bind the function directly in render or anywhere else in the component except in constructor. Because for every function binding a new function/object will be created in webpack bundle js file hence the bundle size will grow. Your component will re-render for many reasons like when you do setState, new props received, when you do this.forceUpdate() etc. So if you directly bind your function in render it will always create a new function. Instead do function binding always in constructor and call the reference wherever required. In this way it creates new function only once because constructor gets called only once per component.

How you should do is something like below

  this.state = {
    value: 'random text'
  this.handleChange = this.handleChange.bind(this);

handleChange (e) {
  console.log('handle change called');

<input value={this.state.value} onChange={this.handleChange}/>

You can also use arrow functions but arrow functions also does create new function every time the component re-renders in certain cases. You should know about when to use arrow function and when are not suppose to. For detailed explation about when to use arrow functions check the accepted answer here

Getting the parent of a directory in Bash

use this : export MYVAR="$(dirname "$(dirname "$(dirname "$(dirname $PWD)")")")" if you want 4th parent directory

export MYVAR="$(dirname "$(dirname "$(dirname $PWD)")")" if you want 3rd parent directory

export MYVAR="$(dirname "$(dirname $PWD)")" if you want 2nd parent directory

Jquery and HTML FormData returns "Uncaught TypeError: Illegal invocation"

I had the same problem

I fixed that by using two options

contentType: false
processData: false

Actually I Added these two command to my $.ajax({}) function

What's the difference between "Write-Host", "Write-Output", or "[console]::WriteLine"?

From my testing Write-Output and [Console]::WriteLine() perform much better than Write-Host.

Depending on how much text you need to write out this may be important.

Below if the result of 5 tests each for Write-Host, Write-Output and [Console]::WriteLine().

In my limited experience, I've found when working with any sort of real world data I need to abandon the cmdlets and go straight for the lower level commands to get any decent performance out of my scripts.

measure-command {$count = 0; while ($count -lt 1000) { Write-Host "hello"; $count++ }}


measure-command { $count = 0; while ($count -lt 1000) { Write-Output "hello"; $count++ }}


measure-command { $count = 0; while ($count -lt 1000) { [console]::WriteLine("hello"); $count++ }}


What is the difference between substr and substring?

Another gotcha I recently came across is that in IE 8, "abcd".substr(-1) erroneously returns "abcd", whereas Firefox 3.6 returns "d" as it should. slice works correctly on both.

More on this topic can be found here.

How to check if array element is null to avoid NullPointerException in Java

The given code works for me. Notice that someArray[i] is always null since you have not initialized the second dimension of the array.

Can't find android device using "adb devices" command

I know this thread is old, but I think this could still help. Almost all the time "it just works" on OS X, but sometimes new/prototype or obscure devices aren't picked up. Try to help it out with these steps (I'm not near my Mac right now, but I did this last night and think I remember):

  1. Open System Profiler and find the device on USB. View it's details to find the Vendor ID. For example, Motorola devices will show 0x2bb8. Or just Google for your vendor's hardware id.

    If nothing shown, make sure to try different cables. Android File Transfer is good for detecting the device if you have a valid cable.

  2. Edit ~/.android/adb_usb.ini to include that Vendor ID. If the file doesn't exist, create it with that line only.

  3. Restart ADB

    adb kill-server 
    adb start-server
  4. Maybe unplug/plugin your phone.

And hopefully you see your device.

What is the role of "Flatten" in Keras?

enter image description here This is how Flatten works converting Matrix to single array.

Download the Android SDK components for offline install

To install android component do following steps

  • Run android sdk manager on offline machine
  • Click on show/hide log window
  • here youu will find all the list of xml files where packages are available

Fetched Add-ons List successfully
Fetching URL:
Validate XML:
Parse XML: is main xml file where all other package list is available.

lets say you want to download platform api-9 and it is available on repository-7 then you have to do following steps

  • note the repository address and go to any other machine which has internet connection and type following link in any browser

  • Search for <sdk:url>****</sdk:url> under the api version which you want to download. This is the file name which you have to download. to download this file you have to type following URI in any downloader or browser and it will start download the file.

    General rule for any file replace with your package name

  • Once the download is complete,paste downloaded ZIP(or other format for other os) file in your flash/pen drive and paste the zip file at <android sdk dir>/temp (ex:- c:\android-sdk\temp) folder/directory in your offline machine.

  • Now start the SDK manager and select the package which you have paste in temp and click Install package button. Your package has been installed.

  • Restart your eclipse and AVD manager to get new packages.

Note:- if you are downloading sdk-tools or sdk platform-tools then choose the package for OS which is on offline machine(windows/Linux/Mac).

Java: Get first item from a collection

It sounds like your Collection wants to be List-like, so I'd suggest:

List<String> myList = new ArrayList<String>();
String first = myList.get(0);

CodeIgniter: Unable to connect to your database server using the provided settings Error Message

If you used this to secure your server:

And then got the error: Code Igniter needs mysql_pconnect() in order to run.

I figured it out once I realized all the Code Igniter websites on the server were broken, so it wasn't a localized connection issue.

How to convert HTML file to word?

Try using pandoc

pandoc -f html -t docx -o output.docx input.html

If the input or output format is not specified explicitly, pandoc will attempt to guess it from the extensions of the input and output filenames.
— pandoc manual

So you can even use

pandoc -o output.docx input.html

Continuous CSS rotation animation on hover, animated back to 0deg on hover out

The solution is to set the default value in your .elem. But this annimation work fine with -moz but not yet implement in -webkit

Look at the fiddle I updated from yours :

It works fine with Firefox but not with Chrome

    position: absolute;_x000D_
    top: 40px;_x000D_
    left: 40px;_x000D_
    width: 0; _x000D_
    height: 0;_x000D_
    border-style: solid;_x000D_
    border-width: 75px;_x000D_
    border-color: red blue green orange;_x000D_
    transition-property: transform;_x000D_
    transition-duration: 1s;_x000D_
.elem:hover {_x000D_
    animation-name: rotate; _x000D_
    animation-duration: 2s; _x000D_
    animation-iteration-count: infinite;_x000D_
    animation-timing-function: linear;_x000D_
@keyframes rotate {_x000D_
    from {transform: rotate(0deg);}_x000D_
    to {transform: rotate(360deg);}_x000D_
<div class="elem"></div>

Get gateway ip address in android

Go to terminal

$ adb -s UDID shell
$ ip addr | grep inet 
$ netcfg | grep inet

Meaning of ${project.basedir} in pom.xml

${project.basedir} is the root directory of your project.

${} is equivalent to ${project.basedir}/target

as it is defined here:

Check if application is on its first run

I'm not sure it's good way to check it. What about case when user uses button "clear data" from settings? SharedPreferences will be cleared and you catch "first run" again. And it's a problem. I guess it's better idea to use InstallReferrerReceiver.

"The operation is not valid for the state of the transaction" error and transaction scope

I've encountered this error when my Transaction is nested within another. Is it possible that the stored procedure declares its own transaction or that the calling function declares one?

Limiting Python input strings to certain characters and lengths

Regexes can also limit the number of characters.

r = re.compile("^[a-z]{1,15}$")

gives you a regex that only matches if the input is entirely lowercase ASCII letters and 1 to 15 characters long.

AngularJS: No "Access-Control-Allow-Origin" header is present on the requested resource

CORS is Cross Origin Resource Sharing, you get this error if you are trying to access from one domain to another domain.

Try using JSONP. In your case, JSONP should work fine because it only uses the GET method.

Try something like this:

var url = "";
    method: 'JSONP',
    url: url
success(function(status) {
    //your code when success
error(function(status) {
    //your code when fails

Slick.js: Get current and total slides (ie. 3/5)

This might help:

  • You don't need to enable dots or customPaging.
  • Position .slick-counter with CSS.




var $el = $('.slideshow');

  slide: 'img',
  autoplay: true,
  onInit: function(e){
    $el.append('<div class="slick-counter">'+ parseInt(e.currentSlide + 1, 10) +' / '+ e.slideCount +'</div>');
  onAfterChange: function(e){
    $el.find('.slick-counter').html(e.currentSlide + 1 +' / '+e.slideCount);

Difference between "managed" and "unmanaged"

This is more general than .NET and Windows. Managed is an environment where you have automatic memory management, garbage collection, type safety, ... unmanaged is everything else. So for example .NET is a managed environment and C/C++ is unmanaged.

How do I tell Python to convert integers into words

#This valid till 4 digit number
numbers={1:'one', 2:'two', 3:'three', 4:'four', 5:'five', 6:'six', 7:'seven', 8:'eight', 9:'nine',
10:'ten', 11:'eleven', 12:'twelve', 13:'thirteen', 14:'fourteen', 15:'fifteen', 16:'sixteen',
17:'seventeen', 18:'eighteen', 19:'nineteen', 20:'twenty', 30:'thirty', 40:'forty', 50:'fifty', 
60:'sixty', 70:'seventy', 80:'eighty', 90:'ninety', 100:'hundred', 1000:'thousand'}

def my_fun(num):
    list = []
    num_len = len(str(num)) - 1
    while num_len > 0 and num > 0:
       while num_len > 0 and num > 0:
        if num in numbers and num < 1000:
            num_len = 0
        elif num < 100:
            list.extend([numbers[num - num%10], numbers[num%10]])
            num_len = 0
            quotent = num//10**num_len # 4567//1000= 4
            num = num % 10**num_len #4567%1000 =567
            if quotent != 0 :
            num_len -= 1
    return ' '.join(list)

How to add (vertical) divider to a horizontal LinearLayout?

I just ran into the same problem today. As the previous answers indicate, the problem stems from the use of a color in the divider tag, rather than a drawable. However, instead of writing my own drawable xml, I prefer to use themed attributes as much as possible. You can use the android:attr/dividerHorizontal and android:attr/dividerVertical to get a predefined drawable instead:

    <!-- other views -->

The attributes are available in API 11 and above.

Also, as mentioned by bocekm in his answer, the dividerPadding property does NOT add extra padding on either side of a vertical divider, as one might assume. Instead it defines top and bottom padding and thus may truncate the divider if it's too large.

Twitter bootstrap remote modal shows same content every time

This one works for me:


<div class="modal fade" id="searchKaryawan" tabindex="-1" role="dialog" aria-labelledby="SearchKaryawanLabel" aria-hidden="true"> <div class="modal-dialog">
<div class="modal-content">
  <div class="modal-header">
    <button type="button" class="close" data-dismiss="modal" aria-label="Close"><span aria-hidden="true">&times;</span></button>
    <h4 class="modal-title" id="SearchKaryawanLabel">Cari Karyawan</h4>
  <div class="modal-body">
    <input type="hidden" name="location">
    <input name="cariNama" type="text" class="form-control" onkeyup="if (this.value.length > 3) cariNikNama();" />
    <div class="links-area" id="links-area"></div>
  <div class="modal-footer">
</div> </div></div>


<script type="text/javascript">$('body').on('', '.modal', function () {  $(".links-area").empty() }); </script>

links-area is area where i put the data and need to clear

Error retrieving parent for item: No resource found that matches the given name after upgrading to AppCompat v23

Another solution : navigate to


open .aar file with 7-zip or winrar , in res folder remove values-23 folder and save changes .

How to SSH into Docker?

I guess it is possible. You just need to install a SSH server in each container and expose a port on the host. The main annoyance would be maintaining/remembering the mapping of port to container.

However, I have to question why you'd want to do this. SSH'ng into containers should be rare enough that it's not a hassle to ssh to the host then use docker exec to get into the container.

How do I create delegates in Objective-C?

When using the formal protocol method for creating delegate support, I've found that you can ensure proper type checking (albeit, runtime, not compile time) by adding something like:

if (![delegate conformsToProtocol:@protocol(MyDelegate)]) {
    [NSException raise:@"MyDelegate Exception"
                format:@"Parameter does not conform to MyDelegate protocol at line %d", (int)__LINE__];

in your delegate accessor (setDelegate) code. This helps minimize mistakes.

Python: Assign print output to a variable

This is a standalone example showing how to save the output of a user-written function in Python 3:

from io import StringIO
import sys

def print_audio_tagging_result(value):
    print(f"value = {value}")

tag_list = []
for i in range(0,1):
    save_stdout = sys.stdout
    result = StringIO()
    sys.stdout = result
    sys.stdout = save_stdout

How can I align all elements to the left in JPanel?

My favorite method to use would be the BorderLayout method. Here are the five examples with each position the component could go in. The example is for if the component were a button. We will add it to a JPanel, p. The button will be called b.

//To align it to the left
p.add(b, BorderLayout.WEST);

//To align it to the right
p.add(b, BorderLayout.EAST);

//To align it at the top
p.add(b, BorderLayout.NORTH);

//To align it to the bottom
p.add(b, BorderLayout.SOUTH);

//To align it to the center
p.add(b, BorderLayout.CENTER);

Don't forget to import it as well by typing:

import java.awt.BorderLayout;

There are also other methods in the BorderLayout class involving things like orientation, but you can do your own research on that if you curious about that. I hope this helped!

How to sum up elements of a C++ vector?

Nobody seems to address the case of summing elements of a vector that can have NaN values in it, e.g. numerical_limits<double>::quite_NaN()

I usually loop through the elements and bluntly check.

vector<double> x;


size_t n = x.size();

double sum = 0;

for (size_t i = 0; i < n; i++){

  sum += (x[i] == x[i] ? x[i] : 0);


It's not fancy at all, i.e. no iterators or any other tricks but I this is how I do it. Some times if there are other things to do inside the loop and I want the code to be more readable I write

double val = x[i];

sum += (val == val ? val : 0);


inside the loop and re-use val if needed.

Check if string contains \n Java

For portability, you really should do something like this:

public static final String NEW_LINE = System.getProperty("line.separator")

unless you're absolutely certain that "\n" is what you want.

Getting HTTP code in PHP using curl

curl_exec is necessary. Try CURLOPT_NOBODY to not download the body. That might be faster.

How to parse JSON string in Typescript

Yes it's a little tricky in TypeScript but you can do the below example like this

let decodeData  =  JSON.parse(`${jsonResponse}`);

How to define a two-dimensional array?

I'm on my first Python script, and I was a little confused by the square matrix example so I hope the below example will help you save some time:

 # Creates a 2 x 5 matrix
 Matrix = [[0 for y in xrange(5)] for x in xrange(2)]

so that

Matrix[1][4] = 2 # Valid
Matrix[4][1] = 3 # IndexError: list index out of range

Override body style for content in an iframe

Perhaps it's changed now, but I have used a separate stylesheet with this element:

.feedEkList iframe
max-width: 435px!important;
width: 435px!important;
height: 320px!important;

to successfully style embedded youtube iframes...see the blog posts on this page.

Select method in List<t> Collection

Well, to start with List<T> does have the FindAll and ConvertAll methods - but the more idiomatic, modern approach is to use LINQ:

// Find all the people older than 30
var query1 = list.Where(person => person.Age > 30);

// Find each person's name
var query2 = list.Select(person => person.Name);

You'll need a using directive in your file to make this work:

using System.Linq;

Note that these don't use strings to express predicates and projects - they use delegates, usually created from lambda expressions as above.

If lambda expressions and LINQ are new to you, I would suggest you get a book covering LINQ first, such as LINQ in Action, Pro LINQ, C# 4 in a Nutshell or my own C# in Depth. You certainly can learn LINQ just from web tutorials, but I think it's such an important technology, it's worth taking the time to learn it thoroughly.

How to remove a class from elements in pure JavaScript?

This might help

let allElements = Array.from(document.querySelectorAll('.widget.hover'))
for (let element of allElements) {

Find out where MySQL is installed on Mac OS X

To check MySQL version of MAMP , use the following command in Terminal:

/Applications/MAMP/Library/bin/mysql --version

Assume you have started MAMP .

Example output:

./mysql  Ver 14.14 Distrib 5.1.44, for apple-darwin8.11.1 (i386) using  EditLine wrapper

UPDATE: Moreover, if you want to find where does mysql installed in system, use the following command:

type -a mysql

type -a is an equivalent of tclsh built-in command where in OS X bash shell. If MySQL is found, it will show :

mysql is /usr/bin/mysql

If not found, it will show:

-bash: type: mysql: not found

By default , MySQL is not installed in Mac OS X.

Sidenote: For XAMPP, the command should be:

/Applications/XAMPP/xamppfiles/bin/mysql --version

How to create a HTML Cancel button that redirects to a URL

There is no button type cancel

To achieve cancel functionality I used DOM history

<button type="button" class="btn btn-primary" onclick="window.history.back();">Cancel</button>

For more details :

List file using ls command in Linux with full path

you just want the full path why not use the utility meant for that a combination of readlink and grep should get you what you want

grep -R  '--include=*.'{mkv,mp4} ? | cut -d ' ' -f3  | xargs readlink -e # 
the question mark should be replaced with the right pattern - this is almost right
# this is probably the best solution remove the grep part if you dont need a filter
find <dirname> | grep .mkv | xargs readlink -e |  xargs ls --color=auto # only matroska files in the dir and subdirs with nice color - also you can edit ls flags
find /mnt/mediashare/net/ | grep .mkv 
find /mnt/mediashare/net/ | xargs grep -R  '--include=*.'{mkv,mp4} . | cut -d ' ' -f3 # I am sure you can do more with grep 
readlink -f `ls` # in the directory or 

How to use php serialize() and unserialize()

When you want to make your php value storable, you have to turn it to be a string value, that is what serialize() does. And unserialize() does the reverse thing.

Android: Cancel Async Task

FOUND THE SOLUTION: I added an action listener before like this:

    uploadingDialog.setOnCancelListener(new DialogInterface.OnCancelListener(){
          public void onCancel(DialogInterface dialog) {

That way when I press the back button, the above OnCancelListener cancels both dialog and task. Also you can add finish() if you want to finish the whole activity on back pressed. Remember to declare your async task as a variable like this:

    MyAsyncTask myTask=null;

and execute your async task like this:

    myTask = new MyAsyncTask();

How do I remove an array item in TypeScript?

let departments is an array. You want to remove an item from this array.

departments: string[] = [];

 removeDepartment(name: string): void {
    this.departments = this.departments.filter(item => item != name);

How to enable php7 module in apache?

First, disable the php5 module:

a2dismod php5

then, enable the php7 module:

a2enmod php7.0

Next, reload/restart the Apache service:

service apache2 restart

Update 2018-09-04

wrt the comment, you need to specify exact installed version.

Android webview slow

If there's only some few components of your webview that is slow or laggy, try adding this to the elements css:

transform: translate3d(0,0,0);
-webkit-transform: translate3d(0,0,0);

This has been the only speedhack that really had a effect on my webview. But be careful not to overuse it! (you can read more about the hack in this article.)

What are the differences between Visual Studio Code and Visual Studio?

Visual Studio

  • IDE
  • Except for free editions, it is a paid IDE.
  • It is quite heavy on CPU and lags on lower end PCs.
  • It is mostly used for Windows software development including DirectX programs, Windows API, etc.
  • Advanced IntelliSense (best one ever; Visual Studio Code's IntelliSense extension takes second place)
  • It features built-in debuggers, easy-to-configure project settings (though developers tend to not use the GUI ones)
  • Microsoft support (more than Visual Studio Code)
  • Mostly used for C/C++ (Windows), .NET and C# projects along with SQL Server, database, etc.
  • Extreme large download size, space utilization and the slow downs over time.
    • It is the only con that forces me to use Visual Studio Code for smaller projects*
  • Includes tools to generate dependency graphs. Refactoring tools have great support for Visual Studio.
  • Has a VYSIWYG editor for VB.NET, C++.NET, and C#. (It is easy enough for first time users instead of getting through windows.h)

Visual Studio Code

  • Free open source text editor
  • Has IntelliSense (but it doesn't work out of box if Visual Studio is not installed, need to configure to point to MinGW, etc.)
  • Smaller download size and RAM requirements. With IntelliSense it requires around 300 MB RAM. (Edit : Some header files tend to blow up memory requirements to 7-8 GBs eg. OpenGL and GLM Libraries)
  • It works on lower-end PCs. (it is still slow to start up especially if PowerShell is used instead of CMD)
  • Lower support (open source, so you can modify it yourself)
  • Build tasks are project specific. Even if you want to build it in a vanilla configuration.
  • Mostly used for web development (this applies to all free text editors). They tend to show off JavaScript / HTML support over C/C++. Visual Studio shows off Visual Basic/C++ over other languages.
  • Lack of good extensions (it's still new though)
  • Gives you a hard time to reconfigure your project/workspace settings. I prefer the GUI way.
  • Cross platform
  • Has an integrated terminal (PowerShell is too slow at startup though)
  • It is best for smaller projects and test code (you know if you are bored and want to print "Hello, World!", it does not make sense to wait 3-5 minutes while Visual Studio loads up, and then another minute or 2 at project creation and then finally getting it to print "Hello, World!").

Selecting option by text content with jQuery

Replace this:

var cat = $.jqURL.get('category');
var $dd = $('#cbCategory');
var $options = $('option', $dd);
$options.each(function() {
if ($(this).text() == cat)
    $(this).select(); // This is where my problem is

With this:


Calling val() on a select list will automatically select the option with that value, if any.

destination path already exists and is not an empty directory

If you got Destination path XXX already exists means the name of the project repository which you are trying to clone is already there in that current directory. So please cross-check and delete any existing one and try to clone it again

How to change dot size in gnuplot

The pointsize command scales the size of points, but does not affect the size of dots.

In other words, plot ... with points ps 2 will generate points of twice the normal size, but for plot ... with dots ps 2 the "ps 2" part is ignored.

You could use circular points (pt 7), which look just like dots.

Blue and Purple Default links, how to remove?

<a href="https://www." style="color: inherit;"target="_blank">

For CSS inline style, this worked best for me.

This compilation unit is not on the build path of a Java project

If your project is imported as an existing maven project then --> Just right click on project and do maven update. It resolved my similar issue. page without a code behind

I thought you could deploy just your .aspx page without the .aspx.cs so long as the DLL was in your bin. Part of the issue here is how visual studio .net works with .aspx pages.

Check it out here: Working with Single-File Web Forms Pages in Visual Studio .NET

I know for sure that VS2008 with MVC RC you don't have code-behind files for your views.

Reading an Excel file in python using pandas

Close: first you call ExcelFile, but then you call the .parse method and pass it the sheet name.

>>> xl = pd.ExcelFile("dummydata.xlsx")
>>> xl.sheet_names
[u'Sheet1', u'Sheet2', u'Sheet3']
>>> df = xl.parse("Sheet1")
>>> df.head()
                  Tid  dummy1    dummy2    dummy3    dummy4    dummy5  \
0 2006-09-01 00:00:00       0  5.894611  0.605211  3.842871  8.265307   
1 2006-09-01 01:00:00       0  5.712107  0.605211  3.416617  8.301360   
2 2006-09-01 02:00:00       0  5.105300  0.605211  3.090865  8.335395   
3 2006-09-01 03:00:00       0  4.098209  0.605211  3.198452  8.170187   
4 2006-09-01 04:00:00       0  3.338196  0.605211  2.970015  7.765058   

     dummy6  dummy7    dummy8    dummy9  
0  0.623354       0  2.579108  2.681728  
1  0.554211       0  7.210000  3.028614  
2  0.567841       0  6.940000  3.644147  
3  0.581470       0  6.630000  4.016155  
4  0.595100       0  6.350000  3.974442  

What you're doing is calling the method which lives on the class itself, rather than the instance, which is okay (although not very idiomatic), but if you're doing that you would also need to pass the sheet name:

>>> parsed =, "Sheet1")
>>> parsed.columns
Index([u'Tid', u'dummy1', u'dummy2', u'dummy3', u'dummy4', u'dummy5', u'dummy6', u'dummy7', u'dummy8', u'dummy9'], dtype=object)

No newline at end of file

The only reason is that Unix historically had a convention of all human-readable text files ending in a newline. At the time, this avoided extra processing when displaying or joining text files, and avoided treating text files differently to files containing other kinds of data (eg raw binary data which isn't human-readable).

Because of this convention, many tools from that era expect the ending newline, including text editors, diffing tools, and other text processing tools. Mac OS X was built on BSD Unix, and Linux was developed to be Unix-compatible, so both operating systems have inherited the same convention, behaviour and tools.

Windows wasn't developed to be Unix-compatible, so it doesn't have the same convention, and most Windows software will deal just fine with no trailing newline.

But, since Git was developed for Linux first, and a lot of open-source software is built on Unix-compatible systems like Linux, Mac OS X, FreeBSD, etc, most open-source communities and their tools (including programming languages) continue to follow these conventions.

There are technical reasons which made sense in 1971, but in this era it's mostly convention and maintaining compatibility with existing tools.

Can't install APK from browser downloads

It shouldn't be HTTP headers if the file has been downloaded successfully and it's the same file that you can open from OI.

A shot in the dark, but could it be that you are not allowing installation from unknown sources, and that OI is somehow bypassing that?

Settings > Applications > Unknown sources...


Answer extracted from comments which worked. Ensure the Content-Type is set to application/

Concatenate string with field value in MySQL

Have you tried using the concat() function?

ON tableTwo.query = concat('category_id=',tableOne.category_id)

What is a None value?

None is a singleton object (meaning there is only one None), used in many places in the language and library to represent the absence of some other value.

For example:
if d is a dictionary, d.get(k) will return d[k] if it exists, but None if d has no key k.

Read this info from a great blog:

Can't connect to MySQL server on 'localhost' (10061) after Installation

Just turn off the firewall and remove the instance configuration. Add a new instance for the server.![Disable Firewall][1] Give he port number correctly as 3306 as default

At least one JAR was scanned for TLDs yet contained no TLDs

If one wants to have the conf\ read one must (see also here) dump this file into the Servers\Tomcat v7.0 Server at localhost-config\ folder and then add the lines :

-Djava.util.logging.config.file="${workspace_loc}\Servers\Tomcat v7.0 Server at localhost-config\" -Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager

to the VM arguments of the launch configuration one is using.

This may have taken a restart or two (or not) but finally I saw in the console in bright red :

FINE: No TLD files were found in [file:/C:/Dropbox/eclipse_workspaces/javaEE/.metadata/.plugins/org.eclipse.wst.server.core/tmp0/wtpwebapps/ted2012/WEB-INF/lib/logback-classic-1.0.7.jar]. Consider adding the JAR to the tomcat.util.scan.DefaultJarScanner.jarsToSkip or org.apache.catalina.startup.TldConfig.jarsToSkip property in CATALINA_BASE/conf/ file. //etc

I still don't know when exactly this FINE warning appears - does not appear immediately on tomcat launch EDIT: from the comment by @Stephan: "The FINE warning appears each time any change is done in the JSP file".

Bonus: To make the warning go away add in :

# Additional JARs (over and above the default JARs listed above) to skip when
# scanning for TLDs. The list must be a comma separated list of JAR file names.

How do you reverse a string in place in C or C++?

Yet another:

#include <stdio.h>
#include <strings.h>

int main(int argc, char **argv) {

  char *reverse = argv[argc-1];
  char *left = reverse;
  int length = strlen(reverse);
  char *right = reverse+length-1;
  char temp;




  printf("%s\n", reverse);


Absolute and Flexbox in React Native

The first step would be to add

position: 'absolute',

then if you want the element full width, add

left: 0,
right: 0,

then, if you want to put the element in the bottom, add

bottom: 0,
// don't need set top: 0

if you want to position the element at the top, replace bottom: 0 by top: 0

Override default Spring-Boot settings in Junit Test


So what I did was to have the standard src/main/resources/ and also a src/test/resources/ where i override some settings for ALL my tests.

Whole Story

I ran into the same problem and was not using profiles either so far. It seemed to be bothersome to have to do it now and remember declaring the profile -- which can be easily forgotten.

The trick is, to leverage that a profile specific application-<profile>.properties overrides settings in the general profile. See

How to change the text color of first select option

I really wanted this (placeholders should look the same for text boxes as select boxes!) and straight CSS wasn't working in Chrome. Here is what I did:

First make sure your select tag has a .has-prompt class.

Then initialize this class somewhere in document.ready.

# Adds a class to select boxes that have prompt currently selected.
# Allows for placeholder-like styling.
# Looks for has-prompt class on select tag.
Mess.Views.SelectPromptStyler = Backbone.View.extend
  el: 'body'

  initialize: ->

    'change select.has-prompt': 'changed'

  changed: (e) ->
    select = @$(e.currentTarget)
    if select.find('option').first().is(':selected')

Then in CSS:

select.prompt-selected {
  color: $placeholder-color;

What is the difference between cssSelector & Xpath and which is better with respect to performance for cross browser testing?

I’m going to hold the unpopular on SO selenium tag opinion that XPath is preferable to CSS in the longer run.

This long post has two sections - first I'll put a back-of-the-napkin proof the performance difference between the two is 0.1-0.3 milliseconds (yes; that's 100 microseconds), and then I'll share my opinion why XPath is more powerful.

Performance difference

Let's first tackle "the elephant in the room" – that xpath is slower than css.

With the current cpu power (read: anything x86 produced since 2013), even on browserstack/saucelabs/aws VMs, and the development of the browsers (read: all the popular ones in the last 5 years) that is hardly the case. The browser's engines have developed, the support of xpath is uniform, IE is out of the picture (hopefully for most of us). This comparison in the other answer is being cited all over the place, but it is very contextual – how many are running – or care about – automation against IE8?

If there is a difference, it is in a fraction of a millisecond.

Yet, most higher-level frameworks add at least 1ms of overhead over the raw selenium call anyways (wrappers, handlers, state storing etc); my personal weapon of choice – RobotFramework – adds at least 2ms, which I am more than happy to sacrifice for what it provides. A network roundtrip from an AWS us-east-1 to BrowserStack's hub is usually 11 milliseconds.

So with remote browsers if there is a difference between xpath and css, it is overshadowed by everything else, in orders of magnitude.

The measurements

There are not that many public comparisons (I've really seen only the cited one), so – here's a rough single-case, dummy and simple one.
It will locate an element by the two strategies X times, and compare the average time for that.

The target – BrowserStack's landing page, and its "Sign Up" button; a screenshot of the html as writing this post:

enter image description here

Here's the test code (python):

from selenium import webdriver
import timeit

if __name__ == '__main__':

    xpath_locator = '//div[@class="button-section col-xs-12 row"]'
    css_locator = 'div.button-section.col-xs-12.row'

    repetitions = 1000

    driver = webdriver.Chrome()

    css_time = timeit.timeit("driver.find_element_by_css_selector(css_locator)", 
                             number=repetitions, globals=globals())
    xpath_time = timeit.timeit('driver.find_element_by_xpath(xpath_locator)', 
                             number=repetitions, globals=globals())


    print("css total time {} repeats: {:.2f}s, per find: {:.2f}ms".
          format(repetitions, css_time, (css_time/repetitions)*1000))
    print("xpath total time for {} repeats: {:.2f}s, per find: {:.2f}ms".
          format(repetitions, xpath_time, (xpath_time/repetitions)*1000))

For those not familiar with Python – it opens the page, and finds the element – first with the css locator, then with the xpath; the find operation is repeated 1,000 times. The output is the total time in seconds for the 1,000 repetitions, and average time for one find in milliseconds.

The locators are:

  • for xpath – "a div element having this exact class value, somewhere in the DOM";
  • the css is similar – "a div element with this class, somewhere in the DOM".

Deliberately chosen not to be over-tuned; also, the class selector is cited for the css as "the second fastest after an id".

The environment – Chrome v66.0.3359.139, chromedriver v2.38, cpu: ULV Core M-5Y10 usually running at 1.5GHz (yes, a "word-processing" one, not even a regular i7 beast).

Here's the output:

css total time 1000 repeats: 8.84s, per find: 8.84ms

xpath total time for 1000 repeats: 8.52s, per find: 8.52ms

Obviously the per find timings are pretty close; the difference is 0.32 milliseconds. Don't jump "the xpath is faster" – sometimes it is, sometimes it's css.

Let's try with another set of locators, a tiny-bit more complicated – an attribute having a substring (common approach at least for me, going after an element's class when a part of it bears functional meaning):

xpath_locator = '//div[contains(@class, "button-section")]'
css_locator = 'div[class~=button-section]'

The two locators are again semantically the same – "find a div element having in its class attribute this substring".
Here are the results:

css total time 1000 repeats: 8.60s, per find: 8.60ms

xpath total time for 1000 repeats: 8.75s, per find: 8.75ms

Diff of 0.15ms.

As an exercise - the same test as done in the linked blog in the comments/other answer - the test page is public, and so is the testing code.

They are doing a couple of things in the code - clicking on a column to sort by it, then getting the values, and checking the UI sort is correct.
I'll cut it - just get the locators, after all - this is the root test, right?

The same code as above, with these changes in:

  • The url is now; there are 2 tests.

  • The locators for the first one - "Finding Elements By ID and Class" - are:

css_locator = '#table2 tbody .dues'
xpath_locator = "//table[@id='table2']//tr/td[contains(@class,'dues')]"

And here is the outcome:

css total time 1000 repeats: 8.24s, per find: 8.24ms

xpath total time for 1000 repeats: 8.45s, per find: 8.45ms

Diff of 0.2 milliseconds.

The "Finding Elements By Traversing":

css_locator = '#table1 tbody tr td:nth-of-type(4)'
xpath_locator = "//table[@id='table1']//tr/td[4]"

The result:

css total time 1000 repeats: 9.29s, per find: 9.29ms

xpath total time for 1000 repeats: 8.79s, per find: 8.79ms

This time it is 0.5 ms (in reverse, xpath turned out "faster" here).

So 5 years later (better browsers engines) and focusing only on the locators performance (no actions like sorting in the UI, etc), the same testbed - there is practically no difference between CSS and XPath.

So, out of xpath and css, which of the two to choose for performance? The answer is simple – choose locating by id.

Long story short, if the id of an element is unique (as it's supposed to be according to the specs), its value plays an important role in the browser's internal representation of the DOM, and thus is usually the fastest.

Yet, unique and constant (e.g. not auto-generated) ids are not always available, which brings us to "why XPath if there's CSS?"

The XPath advantage

With the performance out of the picture, why do I think xpath is better? Simple – versatility, and power.

Xpath is a language developed for working with XML documents; as such, it allows for much more powerful constructs than css.
For example, navigation in every direction in the tree – find an element, then go to its grandparent and search for a child of it having certain properties.
It allows embedded boolean conditions – cond1 and not(cond2 or not(cond3 and cond4)); embedded selectors – "find a div having these children with these attributes, and then navigate according to it".
XPath allows searching based on a node's value (its text) – however frowned upon this practice is, it does come in handy especially in badly structured documents (no definite attributes to step on, like dynamic ids and classes - locate the element by its text content).

The stepping in css is definitely easier – one can start writing selectors in a matter of minutes; but after a couple of days of usage, the power and possibilities xpath has quickly overcomes css.
And purely subjective – a complex css is much harder to read than a complex xpath expression.

Outro ;)

Finally, again very subjective - which one to chose?

IMO, there is no right or wrong choice - they are different solutions to the same problem, and whatever is more suitable for the job should be picked.

Being "a fan" of XPath I'm not shy to use in my projects a mix of both - heck, sometimes it is much faster to just throw a CSS one, if I know it will do the work just fine.

Why are there two ways to unstage a file in Git?

git rm --cached is used to remove a file from the index. In the case where the file is already in the repo, git rm --cached will remove the file from the index, leaving it in the working directory and a commit will now remove it from the repo as well. Basically, after the commit, you would have unversioned the file and kept a local copy.

git reset HEAD file ( which by default is using the --mixed flag) is different in that in the case where the file is already in the repo, it replaces the index version of the file with the one from repo (HEAD), effectively unstaging the modifications to it.

In the case of unversioned file, it is going to unstage the entire file as the file was not there in the HEAD. In this aspect git reset HEAD file and git rm --cached are same, but they are not same ( as explained in the case of files already in the repo)

To the question of Why are there 2 ways to unstage a file in git? - there is never really only one way to do anything in git. that is the beauty of it :)

Excel error HRESULT: 0x800A03EC while trying to get range with cell's name

I have encountered this error code when enumerating names and calling worksheet.get_Range(name). It seems to occur when the name does NOT apply to a range, in my case it is the name of a macro.

CSS display:inline property with list-style-image: property on <li> tags

You want the list items to line up next to each other, but not really be inline elements. So float them instead:

ol.widgets li { 
    float: left;
    margin-left: 10px;

How to Create an excel dropdown list that displays text with a numeric hidden value

There are two types of drop down lists available (I am not sure since which version).

ActiveX Drop Down
You can set the column widths, so your hidden column can be set to 0.

Form Drop Down
You could set the drop down range to a hidden sheet and reference the cell adjacent to the selected item. This would also work with the ActiveX type control.

Get name of current class?

PEP 3155 introduced __qualname__, which was implemented in Python 3.3.

For top-level functions and classes, the __qualname__ attribute is equal to the __name__ attribute. For nested classes, methods, and nested functions, the __qualname__ attribute contains a dotted path leading to the object from the module top-level.

It is accessible from within the very definition of a class or a function, so for instance:

class Foo:

will effectively print Foo. You'll get the fully qualified name (excluding the module's name), so you might want to split it on the . character.

However, there is no way to get an actual handle on the class being defined.

>>> class Foo:
...     print('Foo' in globals())

Reading values from DataTable

I think it will work

for (int i = 1; i <= broj_ds; i++ ) 

     QuantityInIssueUnit_value = dr_art_line_2[i]["Column"];
     QuantityInIssueUnit_uom  = dr_art_line_2[i]["Column"];


Join a list of items with different types as string in Python

Your problem is rather clear. Perhaps you're looking for extend, to add all elements of another list to an existing list:

>>> x = [1,2]
>>> x.extend([3,4,5])
>>> x
[1, 2, 3, 4, 5]

If you want to convert integers to strings, use str() or string interpolation, possibly combined with a list comprehension, i.e.

>>> x = ['1', '2']
>>> x.extend([str(i) for i in range(3, 6)])
>>> x
['1', '2', '3', '4', '5']

All of this is considered pythonic (ok, a generator expression is even more pythonic but let's stay simple and on topic)

Why is using the JavaScript eval function a bad idea?

Unless you are 100% sure that the code being evaluated is from a trusted source (usually your own application) then it's a surefire way of exposing your system to a cross-site scripting attack.

d3 add text to circle

Here's a way that I consider easier: The general idea is that you want to append a text element to a circle element then play around with its "dx" and "dy" attributes until you position the text at the point in the circle that you like. In my example, I used a negative number for the dx since I wanted to have text start towards the left of the centre.

const nodes = [ {id: ABC, group: 1, level: 1}, {id:XYZ, group: 2, level: 1}, ]

const nodeElems = svg.append('g')
.attr('fill', getNodeColor)

const textElems = svg.append('g')
.text(node => node.label)
.attr('font-size',8)//font size
.attr('dx', -10)//positions text towards the left of the center of the circle

Static variable inside of a function in C

Output: 6,7


The declaration of x is inside foo but the x=5 initialization takes place outside of foo!

What we need to understand here is that

static int x = 5;

is not the same as

static int x;
x = 5;

Other answers have used the important words here, scope and lifetime, and pointed out that the scope of x is from the point of its declaration in the function foo to the end of the function foo. For example I checked by moving the declaration to the end of the function, and that makes x undeclared at the x++; statement.

So the static int x (scope) part of the statement actually applies where you read it, somewhere INSIDE the function and only from there onwards, not above it inside the function.

However the x = 5 (lifetime) part of the statement is initialization of the variable and happening OUTSIDE of the function as part of the program loading. Variable x is born with a value of 5 when the program loads.

I read this in one of the comments: "Also, this doesn't address the really confusing part, which is the fact that the initializer is skipped on subsequent calls." It is skipped on all calls. Initialization of the variable is outside of the function code proper.

The value of 5 is theoretically set regardless of whether or not foo is called at all, although a compiler might optimize the function away if you don't call it anywhere. The value of 5 should be in the variable before foo is ever called.

Inside of foo, the statement static int x = 5; is unlikely to be generating any code at all.

I found the address x uses when I put a function foo into a program of mine, and then (correctly) guessed that the same location would be used if I ran the program again. The partial screen capture below shows that x has the value 5 even before the first call to foo.

Break Point before first call to foo

How do I get DOUBLE_MAX?

Its in the standard float.h include file. You want DBL_MAX

Convert String to Uri

What are you going to do with the URI?

If you're just going to use it with an HttpGet for example, you can just use the string directly when creating the HttpGet instance.

HttpGet get = new HttpGet("");

What is the difference between Linear search and Binary search?

binary search runs in O(logn) time whereas linear search runs in O(n) times thus binary search has better performance

Copy Image from Remote Server Over HTTP

If you have PHP5 and the HTTP stream wrapper enabled on your server, it's incredibly simple to copy it to a local file:

copy('', '/tmp/file.jpeg');

This will take care of any pipelining etc. that's needed. If you need to provide some HTTP parameters there is a third 'stream context' parameter you can provide.

How to calculate Average Waiting Time and average Turn-around time in SJF Scheduling?

Gantt chart is wrong... First process P3 has arrived so it will execute first. Since the burst time of P3 is 3sec after the completion of P3, processes P2,P4, and P5 has been arrived. Among P2,P4, and P5 the shortest burst time is 1sec for P2, so P2 will execute next. Then P4 and P5. At last P1 will be executed.

Gantt chart for this ques will be:

| P3 | P2 | P4 | P5 | P1 |

1    4    5    7   11   14

Average waiting time=(0+2+2+3+3)/5=2

Average Turnaround time=(3+3+4+7+6)/5=4.6

What is a file with extension .a?

.a files are static libraries typically generated by the archive tool. You usually include the header files associated with that static library and then link to the library when you are compiling.

Simplest way to detect a pinch

You want to use the gesturestart, gesturechange, and gestureend events. These get triggered any time 2 or more fingers touch the screen.

Depending on what you need to do with the pinch gesture, your approach will need to be adjusted. The scale multiplier can be examined to determine how dramatic the user's pinch gesture was. See Apple's TouchEvent documentation for details about how the scale property will behave.

node.addEventListener('gestureend', function(e) {
    if (e.scale < 1.0) {
        // User moved fingers closer together
    } else if (e.scale > 1.0) {
        // User moved fingers further apart
}, false);

You could also intercept the gesturechange event to detect a pinch as it happens if you need it to make your app feel more responsive.

Replace a string in shell script using a variable

Not related to question but in case if someone is passing the string as an argument to bash script this might help.


./ "path\to\file"

Instead of:

./ path\to\file

For your reference.

How do I make my string comparison case insensitive?

  • The best would be using s1.equalsIgnoreCase(s2): (see javadoc)
  • You can also convert them both to upper/lower case and use s1.equals(s2)

if checkbox is checked, do this

Why not use the built in events?

    if( {
     // code to run if checked

     } else {

     //code to run if unchecked

PANIC: Cannot find AVD system path. Please define ANDROID_SDK_ROOT (in windows 10)

Check C:\Users\User path. Change User directory name (may be something different name) from your alphabet to English alphabet. Warning: it is dangerous operation, learn it before changing. Android Studio can not access to AVD throw users\Your alphabet name\.android.

Which characters are valid/invalid in a JSON key name?

The following characters must be escaped in JSON data to avoid any problems:

  • " (double quote)
  • \ (backslash)
  • all control characters like \n, \t

JSON Parser can help you to deal with JSON.

How does it work - requestLocationUpdates() + LocationRequest/Listener

I use this one:

LocationManager.requestLocationUpdates(String provider, long minTime, float minDistance, LocationListener listener)

For example, using a 1s interval:


the time is in milliseconds, the distance is in meters.

This automatically calls:

public void onLocationChanged(Location location) {
    //Code here, location.getAccuracy(), location.getLongitude() etc...

I also had these included in the script but didnt actually use them:

public void onStatusChanged(String provider, int status, Bundle extras) {}
public void onProviderEnabled(String provider) {}
public void onProviderDisabled(String provider) {}

In short:

public class GPSClass implements LocationListener {

    public void onLocationChanged(Location location) {
        // Called when a new location is found by the network location provider.
        Log.i("Message: ","Location changed, " + location.getAccuracy() + " , " + location.getLatitude()+ "," + location.getLongitude());

    public void onStatusChanged(String provider, int status, Bundle extras) {}
    public void onProviderEnabled(String provider) {}
    public void onProviderDisabled(String provider) {}

    protected void onCreate(Bundle savedInstanceState) {
        locationManager = (LocationManager)getSystemService(Context.LOCATION_SERVICE);