Programs & Examples On #Oracleportal

Oracle Portal is a browser-based, self-service content publishing and site development solution built on Oracle Application Server or WebLogic. It uses portlets (small windows of specialized content area) from different sources as building blocks for Portal pages.

How to count occurrences of a column value efficiently in SQL?

This should work:

SELECT age, count(age) 
  FROM Students 
 GROUP by age

If you need the id as well you could include the above as a sub query like so:

SELECT, S.age, C.cnt
  FROM Students  S
       INNER JOIN (SELECT age, count(age) as cnt
                     FROM Students 
                    GROUP BY age) C ON S.age = C.age

Can I set enum start value in Java?

 public class MyClass {
    public static void main(String args[]) {
     Ids id1 = Ids.OPEN;

enum Ids {
    OPEN(100), CLOSE(200);

    private final int id;
    Ids(int id) { = id; }
    public int getValue() { return id; }

@scottf, You probably confused because of the constructor defined in the ENUM.

Let me explain that.

When class loader loads enum class, then enum constructor also called. On what!! Yes, It's called on OPEN and close. With what values 100 for OPEN and 200 for close

Can I have different value?


public class MyClass {
    public static void main(String args[]) {
     Ids id1 = Ids.OPEN;

enum Ids {
    OPEN(100), CLOSE(200);

    private int id;
    Ids(int id) { = id; }
    public int getValue() { return id; }
    public void setValue(int value) { id = value; }

But, It's bad practice. enum is used for representing constants like days of week, colors in rainbow i.e such small group of predefined constants.

Find size and free space of the filesystem containing a given file

If you just need the free space on a device, see the answer using os.statvfs() below.

If you also need the device name and mount point associated with the file, you should call an external program to get this information. df will provide all the information you need -- when called as df filename it prints a line about the partition that contains the file.

To give an example:

import subprocess
df = subprocess.Popen(["df", "filename"], stdout=subprocess.PIPE)
output = df.communicate()[0]
device, size, used, available, percent, mountpoint = \

Note that this is rather brittle, since it depends on the exact format of the df output, but I'm not aware of a more robust solution. (There are a few solutions relying on the /proc filesystem below that are even less portable than this one.)

Convert number to month name in PHP

This for all needs of date-time converting

 $newDate = new DateTime('2019-03-27 03:41:41');
 echo $newDate->format('M d, Y, h:i:s a');

How to get just the parent directory name of a specific file

Use File's getParentFile() method and String.lastIndexOf() to retrieve just the immediate parent directory.

Mark's comment is a better solution thanlastIndexOf():


These solutions only works if the file has a parent file (e.g., created via one of the file constructors taking a parent File). When getParentFile() is null you'll need to resort to using lastIndexOf, or use something like Apache Commons' FileNameUtils.getFullPath():

=> C:/aaa/bbb/ccc/ddd

There are several variants to retain/drop the prefix and trailing separator. You can either use the same FilenameUtils class to grab the name from the result, use lastIndexOf, etc.

Comparing HTTP and FTP for transferring files

One advantage of FTP is that there is a standard way to list files using dir or ls. Because of this, ftp plays nice with tools such as rsync. Granted, rsync is usually done over ssh, but the option is there.

How to go from one page to another page using javascript?

For MVC developers, to redirect a browser using javascript:

window.location.href = "@Url.Action("Action", "Controller")";


I had to use a slightly extended version @Erwin Brandstetter used:

  _db TEXT := 'some_db';
  _user TEXT := 'postgres_user';
  _password TEXT := 'password';
  CREATE EXTENSION IF NOT EXISTS dblink; -- enable extension 
  IF EXISTS (SELECT 1 FROM pg_database WHERE datname = _db) THEN
    RAISE NOTICE 'Database already exists';
    PERFORM dblink_connect('host=localhost user=' || _user || ' password=' || _password || ' dbname=' || current_database());
    PERFORM dblink_exec('CREATE DATABASE ' || _db);

I had to enable the dblink extension, plus i had to provide the credentials for dblink. Works with Postgres 9.4.


You can also have a look at this related question. That user reported that using a join provided better performance than using a sub query.

HTML inside Twitter Bootstrap popover

You need to create a popover instance that has the html option enabled (place this in your javascript file after the popover JS code):

$('.popover-with-html').popover({ html : true });

What's the difference between Invoke() and BeginInvoke()

Just to give a short, working example to see an effect of their difference

new Thread(foo).Start();

private void foo()
        myTextBox.Text = "bing";

If use BeginInvoke, MessageBox pops simultaneous to the text update. If use Invoke, MessageBox pops after the 3 second sleep. Hence, showing the effect of an asynchronous (BeginInvoke) and a synchronous (Invoke) call.

Flatten nested dictionaries, compressing keys

If you're using pandas there is a function hidden in called nested_to_record which does this exactly.

from import nested_to_record    

flat = nested_to_record(my_dict, sep='_')

1 In pandas versions 0.24.x and older use (without the _)

close fxml window by code, javafx

I implemented this in the following way after receiving a NullPointerException from the accepted answer.

In my FXML:

<Button onMouseClicked="#onMouseClickedCancelBtn" text="Cancel">

In my Controller class:

@FXML public void onMouseClickedCancelBtn(InputEvent e) {
    final Node source = (Node) e.getSource();
    final Stage stage = (Stage) source.getScene().getWindow();

What is your favorite C programming trick?

I love empty if-else and while(0) operators.

For example:

#define CMD1(X) do { foo(x); bar(x); } while (0)
#define CMD2(X) if (1) { foo(x); bar(x); } else

Setting up connection string in ASP.NET to SQL SERVER

You can put this in your web.config file connectionStrings:

<add name="myConnectionString" connectionString="Server=myServerAddress;Database=myDataBase;User ID=myUsername;Password=myPassword;Trusted_Connection=False;" providerName="System.Data.SqlClient"/>

Git: How to check if a local repo is up to date?

If you use

git fetch --dry-run -v <link/to/remote/git/repo>

you'll get feedback about whether it is up-to-date. So basically, you just need to add the "verbose" option to the answer given before.

Could not find folder 'tools' inside SDK

This can also happen due to the bad unzipping process of SDK.It Happend to me. Dont use inbuilt windows unzip process. use WINRAR software for unzipping sdk

How to delete file from public folder in laravel 5.1

For delete file from folder you can use unlink and if you want to delete data from database you can use delete() in laravel

Delete file from folder


For delete record from database

$flight = Flight::find(1);


What is a "web service" in plain English?

A simple definition: A web service is a function that can be accessed by other programs over the web (HTTP).

For example, when you create a website in PHP that outputs HTML, its target is the browser and by extension the human reading the page in the browser. A web service is not targeted at humans but rather at other programs.

So your PHP site that generates a random integer could be a web service if it outputs the integer in a format that may be consumed by another program. It might be in an XML format or another format, as long as other programs can understand the output.

The full definition is obviously more complex but you asked for plain English.

Incorrect string value: '\xF0\x9F\x8E\xB6\xF0\x9F...' MySQL

It may be obvious, but it still was surprising to me, that SET NAMES utf8 is not compatible with utf8mb4 encoding. So for some apps changing table/column encoding was not enough. I had to change encoding in app configuration.

Redmine (ruby, ROR)

In config/database.yml:

  adapter: mysql2
  database: redmine
  host: localhost
  username: redmine
  password: passowrd
  encoding: utf8mb4

Custom Yii application (PHP)

In config/db.php:

return [
    'class' => yii\db\Connection::class,
    'dsn' => 'mysql:host=localhost;dbname=yii',
    'username' => 'yii',
    'password' => 'password',
    'charset' => 'utf8mb4',

If you have utf8mb4 as a column/table encoding and still getting errors like this, make sure that you have configured correct charset for DB connection in your application.

Python strip() multiple characters?

string.translate with table=None works fine.

>>> name = "Barack (of Washington)"
>>> name = name.translate(None, "(){}<>")
>>> print name
Barack of Washington

Make flex items take content width, not width of parent container

Use align-items: flex-start on the container, or align-self: flex-start on the flex items.

No need for display: inline-flex.

An initial setting of a flex container is align-items: stretch. This means that flex items will expand to cover the full length of the container along the cross axis.

The align-self property does the same thing as align-items, except that align-self applies to flex items while align-items applies to the flex container.

By default, align-self inherits the value of align-items.

Since your container is flex-direction: column, the cross axis is horizontal, and align-items: stretch is expanding the child element's width as much as it can.

You can override the default with align-items: flex-start on the container (which is inherited by all flex items) or align-self: flex-start on the item (which is confined to the single item).

Learn more about flex alignment along the cross axis here:

Learn more about flex alignment along the main axis here:

Error: Expression must have integral or unscoped enum type

Your variable size is declared as: float size;

You can't use a floating point variable as the size of an array - it needs to be an integer value.

You could cast it to convert to an integer:

float *temp = new float[(int)size];

Your other problem is likely because you're writing outside of the bounds of the array:

   float *temp = new float[size];

    //Getting input from the user
    for (int x = 1; x <= size; x++){
        cout << "Enter temperature " << x << ": ";

        // cin >> temp[x];
        // This should be:
        cin >> temp[x - 1];

Arrays are zero based in C++, so this is going to write beyond the end and never write the first element in your original code.

Excel Calculate the date difference from today from a cell of "7/6/2012 10:26:42"

Why don't you just make it easy and simple. If I need to know the number of days between today and say, March 10th, 2015, I can just enter the simple formula.

Lets say the static date is March 10th, 2015, and is in cell O5.

The formula to determine the number of days between today and O5 would be, =O5-Today()

Nothing fancy or DATEDIF stuff. Obviously, the cell where you type this formula in must have a data type of 'number'. Just type your date in normally in the reference cell, in this case O5.

How do I pass parameters to a jar file at the time of execution?

The JAVA Documentation says:

java [ options ] -jar file.jar [ argument ... ]


... Non-option arguments after the class name or JAR file name are passed to the main function...

Maybe you have to put the arguments in single quotes.

'dispatch' is not a function when argument to mapToDispatchToProps() in Redux

A pitfall some might step into that is covered by this question but isn't addressed in the answers as it is slightly different in the code structure but returns the exact same error.

This error occurs when using bindActionCreators and not passing the dispatch function

Error Code

import someComponent from './someComponent'
import { connect } from 'react-redux';
import { bindActionCreators } from 'redux'
import { someAction } from '../../../actions/someAction'

const mapStatToProps = (state) => {
    const { someState } = state.someState

    return {

const mapDispatchToProps = (dispatch) => {
    return bindActionCreators({

export default connect(mapStatToProps, mapDispatchToProps)(someComponent)

Fixed Code

import someComponent from './someComponent'
import { connect } from 'react-redux';
import { bindActionCreators } from 'redux'
import { someAction } from '../../../actions/someAction'

const mapStatToProps = (state) => {
    const { someState } = state.someState

    return {

const mapDispatchToProps = (dispatch) => {
    return bindActionCreators({
    }, dispatch);

export default connect(mapStatToProps, mapDispatchToProps)(someComponent)

The function dispatch was missing in the Error code

How do I get the path and name of the file that is currently executing?

I have always just used the os feature of Current Working Directory, or CWD. This is part of the standard library, and is very easy to implement. Here is an example:

    import os
    base_directory = os.getcwd()

How can I create a carriage return in my C# string

string myHTML = "some words " + Environment.NewLine + "more words");

bootstrap datepicker today as default

It works fine for me...

$(document).ready(function() {
        var date = new Date();
        var today = new Date(date.getFullYear(), date.getMonth(), date.getDate());

            format: 'dd-mm-yyyy',
            orientation: 'bottom'

        $('#datepicker1').datepicker('setDate', today);


How do I replace text inside a div element?

I would use Prototype's update method which supports plain text, an HTML snippet or any JavaScript object that defines a toString method.

$("field_name").update("New text");

Angular.js vs Knockout.js vs Backbone.js

It depends on the nature of your application. And, since you did not describe it in great detail, it is an impossible question to answer. I find Backbone to be the easiest, but I work in Angular all day. Performance is more up to the coder than the framework, in my opinion.

Are you doing heavy DOM manipulation? I would use jQuery and Backbone.

Very data driven app? Angular with its nice data binding.

Game programming? None - direct to canvas; maybe a game engine.

How to retrieve the hash for the current commit in Git?

If you want the super-hacky way to do it:

cat .git/`cat .git/HEAD | cut -d \  -f 2`

Basically, git stores the location of HEAD in .git/HEAD, in the form ref: {path from .git}. This command reads that out, slices off the "ref: ", and reads out whatever file it pointed to.

This, of course, will fail in detached-head mode, as HEAD won't be "ref:...", but the hash itself - but you know, I don't think you expect that much smarts in your bash one-liners. If you don't think semicolons are cheating, though...

HASH="ref: HEAD"; while [[ $HASH == ref\:* ]]; do HASH="$(cat ".git/$(echo $HASH | cut -d \  -f 2)")"; done; echo $HASH

How to post JSON to PHP with curl

Jordans analysis of why the $_POST-array isn't populated is correct. However, you can use

$data = file_get_contents("php://input");

to just retrieve the http body and handle it yourself. See PHP input/output streams.

From a protocol perspective this is actually more correct, since you're not really processing http multipart form data anyway. Also, use application/json as content-type when posting your request.

How do I integrate Ajax with Django applications?

I have tried to use AjaxableResponseMixin in my project, but had ended up with the following error message:

ImproperlyConfigured: No URL to redirect to. Either provide a url or define a get_absolute_url method on the Model.

That is because the CreateView will return a redirect response instead of returning a HttpResponse when you to send JSON request to the browser. So I have made some changes to the AjaxableResponseMixin. If the request is an ajax request, it will not call the super.form_valid method, just call the directly.

from django.http import JsonResponse
from django import forms
from django.db import models

class AjaxableResponseMixin(object):
    success_return_code = 1
    error_return_code = 0
    Mixin to add AJAX support to a form.
    Must be used with an object-based FormView (e.g. CreateView)
    def form_invalid(self, form):
        response = super(AjaxableResponseMixin, self).form_invalid(form)
        if self.request.is_ajax():
            form.errors.update({'result': self.error_return_code})
            return JsonResponse(form.errors, status=400)
            return response

    def form_valid(self, form):
        # We make sure to call the parent's form_valid() method because
        # it might do some processing (in the case of CreateView, it will
        # call for example).
        if self.request.is_ajax():
            self.object =
            data = {
                'result': self.success_return_code
            return JsonResponse(data)
            response = super(AjaxableResponseMixin, self).form_valid(form)
            return response

class Product(models.Model):
    name = models.CharField('product name', max_length=255)

class ProductAddForm(forms.ModelForm):
    Product add form
    class Meta:
        model = Product
        exclude = ['id']

class PriceUnitAddView(AjaxableResponseMixin, CreateView):
    Product add view
    model = Product
    form_class = ProductAddForm

How do you get git to always pull from a specific branch?

git branch --set-upstream master origin/master

This will add the following info to your config file:

[branch "master"]
    remote = origin
    merge = refs/heads/master

If you have branch.autosetuprebase = always then it will also add:

    rebase = true

Force IE8 Into IE7 Compatiblity Mode

my code has this tag

meta http-equiv="X-UA-Compatible" content="IE=7" />

is there a way where i can skip this tag and yet layouts get displayed well and fine using that tag the display will work upto IE 7 but i want to run it wel in further versions...

How to get jQuery dropdown value onchange event

If you have simple dropdown like:

<select name="status" id="status">
    <option value="1">Active</option>
    <option value="0">Inactive</option>

Then you can use this code for getting value:


     var status = this.value;
     $("#icon_class, #background_class").hide();// hide multiple sections


Java Replacing multiple different substring in a string at once (or in the most efficient way)

If you are going to be changing a String many times, then it is usually more efficient to use a StringBuilder (but measure your performance to find out):

String str = "The rain in Spain falls mainly on the plain";
StringBuilder sb = new StringBuilder(str);
// do your replacing in sb - although you'll find this trickier than simply using String
String newStr = sb.toString();

Every time you do a replace on a String, a new String object is created, because Strings are immutable. StringBuilder is mutable, that is, it can be changed as much as you want.

Attribute Error: 'list' object has no attribute 'split'

what i did was a quick fix by converting readlines to string but i do not recommencement it but it works and i dont know if there are limitations or not

`def getQuakeData():
    filename = input("Please enter the quake file: ")
    readfile = open(filename, "r")
    readlines = str(readfile.readlines())

    Type = readlines.split(",")
    x = Type[1]
    y = Type[2]
    for points in Type:

Create a 3D matrix

If you want to define a 3D matrix containing all zeros, you write

A = zeros(8,4,20);

All ones uses ones, all NaN's uses NaN, all false uses false instead of zeros.

If you have an existing 2D matrix, you can assign an element in the "3rd dimension" and the matrix is augmented to contain the new element. All other new matrix elements that have to be added to do that are set to zero.

For example

B = magic(3); %# creates a 3x3 magic square
B(2,1,2) = 1; %# and you have a 3x3x2 array

set value of input field by php variable's value

One way to do it will be to move all the php code above the HTML, copy the result to a variable and then add the result in the <input> tag.
Try this -

//Adding the php to the top.
        //Adding to $result variable
    if($sign=='-') {
      $result = $value1-$value2;
    //Rest of your code...
<!--Rest of your tags...-->
Result:<br><input type"text" name="result" value = "<?php echo (isset($result))?$result:'';?>">

What's the difference between django OneToOneField and ForeignKey?

The easiest way to draw a relationship between items is by understanding them in plain languages. Example

A user can have many cars but then a car can have just one owner. After establishing this, the foreign key should be used on the item with the many relationship. In this case the car. Meaning you'll include user as a foreign key in cars

And a one on one relationship is quite simple. Say a man and a heart. A man has only one heart and a heart can belong to just one man

How to set the Default Page in ASP.NET?

Tip #84: Did you know… How to set a Start page for your Web Site in Visual Web Developer?

Simply right click on the page you want to be the start page and say "set as start page".

As noted in the comment below by Adam Tuliper - MSFT, this only works for debugging, not deployment.

Create a txt file using batch file in a specific folder

You can also use

cd %localhost%

to set the directory to the folder the batch file was opened from. Your script would look like this:

@echo off
cd %localhost%
echo .> dblank.txt

Make sure you set the directory before you use the command to create the text file.

How to save python screen output to a text file

You would probably want this. Simplest solution would be

Create file first.

open file via

f = open('<filename>', 'w')


f = open('<filename>', 'a')

in case you want to append to file

Now, write to the same file via

f.write(<text to be written>)

Close the file after you are done using it

#good pracitice

ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: NO)

The following steps are to reset the password for a user in case you forgot, this would also solve your mentioned error.

First, stop your MySQL:

sudo /etc/init.d/mysql stop

Now start up MySQL in safe mode and skip the privileges table:

sudo mysqld_safe --skip-grant-tables &

Login with root:

mysql -uroot

And assign the DB that needs to be used:

use mysql;

Now all you have to do is reset your root password of the MySQL user and restart the MySQL service:

update user set password=PASSWORD("YOURPASSWORDHERE") where User='root';

flush privileges;

quit and restart MySQL:


sudo /etc/init.d/mysql stop sudo /etc/init.d/mysql start Now your root password should be working with the one you just set, check it with:

mysql -u root -p

In HTML5, should the main navigation be inside or outside the <header> element?

@IanDevlin is correct. MDN's rules say the following:

"The HTML Header Element "" defines a page header — typically containing the logo and name of the site and possibly a horizontal menu..."

The word "possibly" there is key. It goes on to say that the header doesn't necessarily need to be a site header. For instance you could include a "header" on a pop-up modal or on other modular parts of the document where there is a header and it would be helpful for a user on a screen reader to know about it.

It terms of the implicit use of NAV you can use it anywhere there is grouped site navigation, although it's usually omitted from the "footer" section for mini-navs / important site links.

Really it comes down to personal / team choice. Decide what you and your team feel is more semantic and more important and the try to be consistent. For me, if the nav is inline with the logo and the main site's "h1" then it makes sense to put it in the "header" but if you have a different design choice then decide on a case by case basis.

Most importantly check out the docs and be sure if you choose to omit or include you understand why you are making that particular decision.

Does JSON syntax allow duplicate keys in an object?

I came across a similar question when dealing with an API that accepts both XML and JSON, but doesn't document how it would handle what you'd expect to be duplicate keys in the JSON accepted.

The following is a valid XML representation of your sample JSON:


When this is converted into JSON, you get the following:

  "object": {
    "a": [

A natural mapping from a language that handles what you might call duplicate keys to another, can serve as a potential best practice reference here.

Hope that helps someone!

Submitting HTML form using Jquery AJAX

If you add:


You can simply do this:

$('#myform').ajaxForm(function(response) {

// this will register the AJAX for <form id="myform" action="some_url">
// and when you submit the form using <button type="submit"> or $('myform').submit(), then it will send your request and alert response


You could use simple $('FORM').serialize() as suggested in post above, but that will not work for FILE INPUTS... ajaxForm() will.

How do I set the eclipse.ini -vm option?

I'd like to share this little hack:

A click on the Eclipse's icon indicated a problem with the JRE. So, I put this command in the destination field of the icon's properties:

C:\...\eclipse.exe -vm c:\'Program Files'\Java\jdk1.7.0_51\jre\bin\javaw

Thinking that the "'" would solve the problem with the space in the path. That did not function. Then, I tried this command:

C:\...\eclipse.exe -vm c:\Progra~1\Java\jdk1.7.0_51\jre\bin\javaw

with success

How do you redirect HTTPS to HTTP?

all the above did not work when i used cloudflare, this one worked for me:

RewriteCond %{HTTP:X-Forwarded-Proto} =https
RewriteRule ^(.*)$ http://%{HTTP_HOST}%{REQUEST_URI} [L,R=301]

and this one definitely works without proxies in the way:

RewriteCond %{HTTPS} on
RewriteRule (.*) http://%{HTTP_HOST}%{REQUEST_URI} [R=301,L]

Difference between RegisterStartupScript and RegisterClientScriptBlock?

Here's an old discussion thread where I listed the main differences and the conditions in which you should use each of these methods. I think you may find it useful to go through the discussion.

To explain the differences as relevant to your posted example:

a. When you use RegisterStartupScript, it will render your script after all the elements in the page (right before the form's end tag). This enables the script to call or reference page elements without the possibility of it not finding them in the Page's DOM.

Here is the rendered source of the page when you invoke the RegisterStartupScript method:

<html xmlns="">
<head id="Head1"><title></title></head>
    <form name="form1" method="post" action="StartupScript.aspx" id="form1">
            <input type="hidden" name="__VIEWSTATE" id="__VIEWSTATE" value="someViewstategibberish" />
        <div> <span id="lblDisplayDate">Label</span>
            <br />
            <input type="submit" name="btnPostback" value="Register Startup Script" id="btnPostback" />
            <br />
            <input type="submit" name="btnPostBack2" value="Register" id="btnPostBack2" />
            <input type="hidden" name="__EVENTVALIDATION" id="__EVENTVALIDATION" value="someViewstategibberish" />
        <!-- Note this part -->
        <script language='javascript'>
            var lbl = document.getElementById('lblDisplayDate');
   = 'red';
    <!-- Note this part -->

b. When you use RegisterClientScriptBlock, the script is rendered right after the Viewstate tag, but before any of the page elements. Since this is a direct script (not a function that can be called, it will immediately be executed by the browser. But the browser does not find the label in the Page's DOM at this stage and hence you should receive an "Object not found" error.

Here is the rendered source of the page when you invoke the RegisterClientScriptBlock method:

<html xmlns="">
<head id="Head1"><title></title></head>
    <form name="form1" method="post" action="StartupScript.aspx" id="form1">
            <input type="hidden" name="__VIEWSTATE" id="__VIEWSTATE" value="someViewstategibberish" />
        <script language='javascript'>
            var lbl = document.getElementById('lblDisplayDate');
            // Error is thrown in the next line because lbl is null.
   = 'green';

Therefore, to summarize, you should call the latter method if you intend to render a function definition. You can then render the call to that function using the former method (or add a client side attribute).

Edit after comments:

For instance, the following function would work:

protected void btnPostBack2_Click(object sender, EventArgs e) 
  System.Text.StringBuilder sb = new System.Text.StringBuilder(); 
  sb.Append("<script language='javascript'>function ChangeColor() {"); 
  sb.Append("var lbl = document.getElementById('lblDisplayDate');"); 

  //Render the function definition. 
  if (!ClientScript.IsClientScriptBlockRegistered("JSScriptBlock")) 
    ClientScript.RegisterClientScriptBlock(this.GetType(), "JSScriptBlock", sb.ToString()); 

  //Render the function invocation. 
  string funcCall = "<script language='javascript'>ChangeColor();</script>"; 

  if (!ClientScript.IsStartupScriptRegistered("JSScript"))
    ClientScript.RegisterStartupScript(this.GetType(), "JSScript", funcCall); 

jQuery - Uncaught RangeError: Maximum call stack size exceeded

your fadeIn() function calls the fadeOut() function, which calls the fadeIn() function again. the recursion is in the JS.

How do I make an HTML text box show a hint when empty?

if ($(this).attr('class')=='hint') 

  if($(this).val() == '')

<input type="text" value="" title="Default Watermark Text">

Choosing bootstrap vs material design

As far as I know you can use all mentioned technologies separately or together. It's up to you. I think you look at the problem from the wrong angle. Material Design is just the way particular elements of the page are designed, behave and put together. Material Design provides great UI/UX, but it relies on the graphic layout (HTML/CSS) rather than JS (events, interactions).

On the other hand, AngularJS and Bootstrap are front-end frameworks that can speed up your development by saving you from writing tons of code. For example, you can build web app utilizing AngularJS, but without Material Design. Or You can build simple HTML5 web page with Material Design without AngularJS or Bootstrap. Finally you can build web app that uses AngularJS with Bootstrap and with Material Design. This is the best scenario. All technologies support each other.

  1. Bootstrap = responsive page
  2. AngularJS = MVC
  3. Material Design = great UI/UX

You can check awesome material design components for AngularJS:

enter image description here

Demo: enter image description here

jQuery if statement, syntax

I little sophisticated way:

$(selector).is(condition)? alert('true') : alert('false');


$("#btn-primary").is(":disabled")? alert('button disabled') : alert('button disabled');

Can I disable a CSS :hover effect via JavaScript?

Actually an other way to solve this could be, overwriting the CSS with insertRule.

It gives the ability to inject CSS rules to an existing/new stylesheet. In my concrete example it would look like this:

//creates a new `style` element in the document
var sheet = (function(){
  var style = document.createElement("style");
  // WebKit hack :(
  // Add the <style> element to the page
  return style.sheet;

//add the actual rules to it
 "ul#mainFilter a:hover { color: #0000EE }" , 0

Demo with my 4 years old original example:

JQuery .hasClass for multiple values in an if statement

For anyone wondering about some of the different performance aspects with all of these different options, I've created a jsperf case here: jsperf

In short, using element.hasClass('class') is the fastest.

Next best bet is using elem.hasClass('classA') || elem.hasClass('classB'). A note on this one: order matters! If the class 'classA' is more likely to be found, list it first! OR condition statements return as soon as one of them is met.

The worst performance by far was using'.class').

Also listed in the jsperf is CyberMonk's function, and Kolja's solution.

Git push requires username and password

I just came across the same problem, and the simplest solution I found was to use SSH URL instead of HTTPS one:

ssh://[email protected]/username/repo.git

And not this:

You can now validate with just the SSH key instead of the username and password.

Ignore outliers in ggplot2 boxplot

Ipaper::geom_boxplot2 is just what you want.

# devtools::install_github('kongdd/Ipaper')
p <- ggplot(mpg, aes(class, hwy))
p + geom_boxplot2(width = 0.8, width.errorbar = 0.5)

enter image description here

MySQL case sensitive query

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

In my case this amounted to defining my column as:

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

This is in my opinion preferential to adjusting your queries.

Replace whitespace with a comma in a text file in Linux

What about something like this :

cat texte.txt | sed -e 's/\s/,/g' > texte-new.txt

(Yes, with some useless catting and piping ; could also use < to read from the file directly, I suppose -- used cat first to output the content of the file, and only after, I added sed to my command-line)

EDIT : as @ghostdog74 pointed out in a comment, there's definitly no need for thet cat/pipe ; you can give the name of the file to sed :

sed -e 's/\s/,/g' texte.txt > texte-new.txt

If "texte.txt" is this way :

$ cat texte.txt
this is a text
in which I want to replace
spaces by commas

You'll get a "texte-new.txt" that'll look like this :

$ cat texte-new.txt

I wouldn't go just replacing the old file by the new one (could be done with sed -i, if I remember correctly ; and as @ghostdog74 said, this one would accept creating the backup on the fly) : keeping might be wise, as a security measure (even if it means having to rename it to something like "texte-backup.txt")

Catching KeyboardInterrupt in Python during program shutdown

You could ignore SIGINTs after shutdown starts by calling signal.signal(signal.SIGINT, signal.SIG_IGN) before you start your cleanup code.

Convert file: Uri to File in Android

By the following code, I am able to get adobe application shared pdf file as a stream and saving into android application path

Android.Net.Uri fileuri =

    fileuri i am getting as {content://com.adobe.reader.fileprovider/root_external/

    string filePath = fileuri.Path;

   filePath I am gettings as root_external/data/data/com.adobe.reader/files/Download/sample.pdf

      using (var stream = ContentResolver.OpenInputStream(fileuri))
       byte[] fileByteArray = ToByteArray(stream); //only once you can read bytes from stream second time onwards it has zero bytes

       string fileDestinationPath ="<path of your destination> "
       convertByteArrayToPDF(fileByteArray, fileDestinationPath);//here pdf copied to your destination path
     public static byte[] ToByteArray(Stream stream)
            var bytes = new List<byte>();

            int b;
            while ((b = stream.ReadByte()) != -1)

            return bytes.ToArray();

      public static string convertByteArrayToPDF(byte[] pdfByteArray, string filePath)

                Java.IO.File data = new Java.IO.File(filePath);
                Java.IO.OutputStream outPut = new Java.IO.FileOutputStream(data);
                return data.AbsolutePath;

            catch (System.Exception ex)
                return string.Empty;

How to resolve Unable to load authentication plugin 'caching_sha2_password' issue

I did exactly the same issue using the dependency below:


I just change to version 46 and everything works.

How can I read a large text file line by line using Java?

You can read file data line by line as below:

String fileLoc = "fileLocationInTheDisk";

List<String> lines = Files.lines(Path.of(fileLoc), StandardCharsets.UTF_8).collect(Collectors.toList());

Convert bytes to a string

In Python 3, the default encoding is "utf-8", so you can directly use:


which is equivalent to


On the other hand, in Python 2, encoding defaults to the default string encoding. Thus, you should use:


where encoding is the encoding you want.

Note: support for keyword arguments was added in Python 2.7.

MySQL LEFT JOIN 3 tables

    Persons p
left join
        Person_Fear pf
    inner join
        Fears f
        pf.fearID = f.fearID
    p.personID = pf.PersonID

Compare object instances for equality by their attributes

When comparing instances of objects, the __cmp__ function is called.

If the == operator is not working for you by default, you can always redefine the __cmp__ function for the object.


As has been pointed out, the __cmp__ function is deprecated since 3.0. Instead you should use the “rich comparison” methods.

How to change users in TortoiseSVN

Replace the line in htpasswd file:

Go to:

(If the link is expired, search another generator from

Enter your username and password. The site will generate an encrypted line. Copy that line and replace it with the previous line in the file "repo/htpasswd".

You might also need to Clear the 'Authentication data' from TortoiseSVN ? Settings ? Saved Data.

Object passed as parameter to another class, by value or reference?

Objects will be passed by reference irrespective of within methods of same class or another class. Here is a modified version of same sample code to help you understand. The value will be changed to 'xyz.'

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Text;

namespace ConsoleApplication1
    public class Employee
        public string Name { get; set; }

    public class MyClass
        public Employee EmpObj;

        public void SetObject(Employee obj)
            EmpObj = obj;

    public class Program
       static void Main(string[] args)
            Employee someTestObj = new Employee();
            someTestObj.Name = "ABC";

            MyClass cls = new MyClass();

            Console.WriteLine("Changing Emp Name To xyz");
            someTestObj.Name = "xyz";

            Console.WriteLine("Accessing Assigned Emp Name");


AttributeError: Can only use .dt accessor with datetimelike values

First you need to define the format of date column.

df['Date'] = pd.to_datetime(df.Date, format='%Y-%m-%d %H:%M:%S')

For your case base format can be set to;

df['Date'] = pd.to_datetime(df.Date, format='%Y-%m-%d')

After that you can set/change your desired output as follows;

df['Date'] = df['Date'].dt.strftime('%Y-%m-%d')

How to add "required" attribute to mvc razor viewmodel text input editor

@Erik's answer didn't fly for me.

Following did:

 @Html.TextBoxFor(m => m.ShortName,  new { data_val_required = "You need me" })

plus doing this manually under field I had to add error message container

@Html.ValidationMessageFor(m => m.ShortName, null, new { @class = "field-validation-error", data_valmsg_for = "ShortName" })

Hope this saves you some time.

How to change PHP version used by composer

I found out that composer runs with the php-version /usr/bin/env finds first in $PATH, which is 7.1.33 in my case on MacOs. So shifting mamp's php to the beginning helped me here.

PHPVER=$(/usr/libexec/PlistBuddy -c "print phpVersion" ~/Library/Preferences/de.appsolute.mamppro.plist)

export PATH=/Applications/MAMP/bin/php/php${PHPVER}/bin:$PATH

Create a date from day month and year with T-SQL

For SQL Server versions below 12 i can recommend use of CAST in combination with SET DATEFORMAT

-- 26 February 2015
SELECT CAST('26-2-2015' AS DATE)

SELECT CAST('2015-2-26' AS DATE)

how you create those strings is up to you

What is the difference between persist() and merge() in JPA and Hibernate?

This is coming from JPA. In a very simple way:

  • persist(entity) should be used with totally new entities, to add them to DB (if entity already exists in DB there will be EntityExistsException throw).

  • merge(entity) should be used, to put entity back to persistence context if the entity was detached and was changed.

Cannot serve WCF services in IIS on Windows 8

For Windows Server 2012, the solution is very similar to faester's (see above). From the Server Manager, click on Add roles and features, select the appropriate server, then select Features. Under .NET Framework 4.5 Features, you'll see WCF Services, and under that, you'll find HTTP Activation.

Display fullscreen mode on Tkinter

I think this is what you're looking for:

Tk.attributes("-fullscreen", True)  # substitute `Tk` for whatever your `Tk()` object is called

You can use wm_attributes instead of attributes, too.

Then just bind the escape key and add this to the handler:

Tk.attributes("-fullscreen", False)

An answer to another question alluded to this (with wm_attributes). So, that's how I found out. But, no one just directly went out and said it was the answer for some reason. So, I figured it was worth posting.

Here's a working example (tested on Xubuntu 14.04) that uses F11 to toggle fullscreen on and off and where escape will turn it off only:

import sys
if sys.version_info[0] == 2:  # Just checking your Python version to import Tkinter properly.
    from Tkinter import *
    from tkinter import *

class Fullscreen_Window:

    def __init__(self): = Tk()'-zoomed', True)  # This just maximizes it so we can see the window. It's nothing to do with fullscreen.
        self.frame = Frame(
        self.state = False"<F11>", self.toggle_fullscreen)"<Escape>", self.end_fullscreen)

    def toggle_fullscreen(self, event=None):
        self.state = not self.state  # Just toggling the boolean"-fullscreen", self.state)
        return "break"

    def end_fullscreen(self, event=None):
        self.state = False"-fullscreen", False)
        return "break"

if __name__ == '__main__':
    w = Fullscreen_Window()

If you want to hide a menu, too, there are only two ways I've found to do that. One is to destroy it. The other is to make a blank menu to switch between.  # self.blank_menu is a Menu object

Then switch it back to your menu when you want it to show up again.  # is your menu.

mysqli_fetch_array() expects parameter 1 to be mysqli_result, boolean given in

That query is failing and returning false.

Put this after mysqli_query() to see what's going on.

if (!$check1_res) {
    printf("Error: %s\n", mysqli_error($con));

For more information:

Proper way to declare custom exceptions in modern Python?

Try this Example

class InvalidInputError(Exception):
    def __init__(self, msg):
        self.msg = msg
    def __str__(self):
        return repr(self.msg)

inp = int(input("Enter a number between 1 to 10:"))
    if type(inp) != int or inp not in list(range(1,11)):
        raise InvalidInputError
except InvalidInputError:
    print("Invalid input entered")

PHP7 : install ext-dom issue

sudo apt install php-xml will work but the thing is it will download the plugin for the latest PHP version.

If your PHP version is not the latest, then you can add version in it:

# PHP 7.1
sudo apt install php7.1-xml

# PHP 7.2:
sudo apt install php7.2-xml

# PHP 7.3
sudo apt install php7.3-xml

# PHP 7.4
sudo apt install php7.4-xml

# PHP 8
sudo apt install php-xml

Using FFmpeg in .net?

A solution that is viable for both Linux and Windows is to just get used to using console ffmpeg in your code. I stack up threads, write a simple thread controller class, then you can easily make use of what ever functionality of ffmpeg you want to use.

As an example, this contains sections use ffmpeg to create a thumbnail from a time that I specify.

In the thread controller you have something like

List<ThrdFfmpeg> threads = new List<ThrdFfmpeg>();

Which is the list of threads that you are running, I make use of a timer to Pole these threads, you can also set up an event if Pole'ing is not suitable for your application. In this case thw class Thrdffmpeg contains,

public class ThrdFfmpeg
    public FfmpegStuff ffm { get; set; }
    public Thread thrd { get; set; }

FFmpegStuff contains the various ffmpeg functionality, thrd is obviously the thread.

A property in FfmpegStuff is the class FilesToProcess, which is used to pass information to the called process, and receive information once the thread has stopped.

public class FileToProcess
    public int videoID { get; set; }
    public string fname { get; set; }
    public int durationSeconds { get; set; }
    public List<string> imgFiles { get; set; }

VideoID (I use a database) tells the threaded process which video to use taken from the database. fname is used in other parts of my functions that use FilesToProcess, but not used here. durationSeconds - is filled in by the threads that just collect video duration. imgFiles is used to return any thumbnails that were created.

I do not want to get bogged down in my code when the purpose of this is to encourage the use of ffmpeg in easily controlled threads.

Now we have our pieces we can add to our threads list, so in our controller we do something like,

        ThrdFfmpeg thrd;
        FileToProcess ftp;

        foreach(FileToProcess ff in  `dbhelper.GetFileNames(txtCategory.Text))`
            //make a thread for each
            ftp = new FileToProcess();
            ftp = ff;
            ftp.imgFiles = new List<string>();
            thrd = new ThrdFfmpeg();
            thrd.ffm = new FfmpegStuff();
            thrd.ffm.filetoprocess = ftp;
            thrd.thrd = new   `System.Threading.Thread(thrd.ffm.CollectVideoLength);`


Now Pole'ing our threads becomes a simple task,

private void timerThreads_Tick(object sender, EventArgs e)
        int runningCount = 0;
        int finishedThreads = 0;
        foreach(ThrdFfmpeg thrd in threads)
            switch (thrd.thrd.ThreadState)
                case System.Threading.ThreadState.Running:

 //Note that you can still view data progress here,
    //but remember that you must use your safety checks
    //here more than anywhere else in your code, make sure the data
    //is readable and of the right sort, before you read it.
                case System.Threading.ThreadState.StopRequested:
                case System.Threading.ThreadState.SuspendRequested:
                case System.Threading.ThreadState.Background:
                case System.Threading.ThreadState.Unstarted:

//Any threads that have been added but not yet started, start now
                case System.Threading.ThreadState.Stopped:

//You can now safely read the results, in this case the
   //data contained in FilesToProcess
   //Such as
                    ThumbnailsReadyEvent( thrd.ffm );
                case System.Threading.ThreadState.WaitSleepJoin:
                case System.Threading.ThreadState.Suspended:
                case System.Threading.ThreadState.AbortRequested:
                case System.Threading.ThreadState.Aborted:

        {//just a simple indicator so that I can see
         //that at least one thread is still running
            lbThreadStatus.BackColor = Color.White;
            flash = false;
            lbThreadStatus.BackColor = this.BackColor;
            flash = true;
        if(finishedThreads >= threads.Count())


Putting your own events onto into the controller class works well, but in video work, when my own code is not actually doing any of the video file processing, poling then invoking an event in the controlling class works just as well.

Using this method I have slowly built up just about every video and stills function I think I will ever use, all contained in the one class, and that class as a text file is useable on the Lunux and Windows version, with just a small number of pre-process directives.

Public free web services for testing soap client

There is a bunch on here:

Just google for "Free WebService" or "Open WebService" and you'll find tons of open SOAP endpoints.

Remember, you can get a WSDL from any ASMX endpoint by adding ?WSDL to the url.

Matching a Forward Slash with a regex

You can escape it like this.

/\//ig; //  Matches /

or just use indexOf

if(str.indexOf("/") > -1)

Which mime type should I use for mp3

Your best bet would be using the RFC defined mime-type audio/mpeg.

SQL Server : login success but "The database [dbName] is not accessible. (ObjectExplorer)"

This is caused when the user's default database is set to a database they don't have permissions or its offline.

Just try to re add the user.Pleae have a look here too.

How to display special characters in PHP

$str = "Is your name O\'vins?";

// Outputs: Is your name O'vins? echo stripslashes($str);

Mysql password expired. Can't connect

restart MySQL server with --skip-grant-tables option And then set a new root password

$ mysql -u root
mysql> USE mysql;
mysql> UPDATE user SET password=PASSWORD("NEWPASSWORD") WHERE User='root';
mysql> quit

Now if you need, you can update mysql.user table(field password_expired='N') not to expire the password.

Can't use Swift classes inside Objective-C

Don't create the header file yourself. Delete the one you created.

Make sure your Swift classes are tagged with @objc or inherit from a class that derives (directly or indirectly) from NSObject.

Xcode won't generate the file if you have any compiler errors in your project - make sure your project builds cleanly.

Vertically align an image inside a div with responsive height

Try this one

          vertical-align: middle;

set up device for development (???????????? no permissions)

I know this might be a little late but here is a very good article on how to manually add Android ADB USB Driver. Manually adding Android ADB USB driver in Ubuntu 14.04 LTS

Edited to Add Link Content


Note: Make sure that you have connected your Android device in USB Debugging mode

Open terminal (CTRL + ALT + T) and enter command: lsusb

Now you might get a similar reply to this:
Bus 002 Device 013: ID 283b:1024

Note: With reference to this Bus 002 Device 008: ID 283b:1024
{idVendor}==”283b” {idProduct}==”1024"

Now enter the following command: sudo gedit /etc/udev/rules.d/51-android.rules
This creates the android rules file (51-android.rules) or open the existing one in the specified location (/etc/udev/rules.d)

Add a new line to this file:
SUBSYSTEM==”usb”, ATTRS{idVendor}==”283b”, ATTRS{idProduct}==”1024", MODE=”0666"

Note Edit idVendor & idProduct values with your device values. Save and close.

Now enter the following command:
sudo chmod a+rx /etc/udev/rules.d/51-android.rules - grant read/execution permission
sudo service udev restart - Restart the udev service

Now we have to add the idVendor to adb_usb.ini. Enter the following commands:
cd ~/.android
gedit adb_usb.ini

Add the following value 0x283b

This is nothing but 0x(idVendor value). So replace the value with. respect to your device value Save and close the file.

Now enter the following command:
sudo service udev restart

Plug out the Android device and reconnect it again.
Now enter the following command:
adb kill-server
adb devices

There you go! Your device must be listed.

Copied From Manually adding Android ADB USB driver in Ubuntu 14.04 LTS

Worked for me.

How to get current language code with Swift?

This is what I use in Swift 5 Xcode 11:

Inside the class variables:

let languagePrefix = Bundle.main.preferredLocalizations.first?.prefix(2)

This comes as a string. It returns 2 characters, i.e. "en", "es", "de"...

From this I can easily determine what language to display:

 if languagePrefix == "es" { self.flipCard.setTitle("última carta", for: .normal) }
 if languagePrefix == "en" { self.flipCard.setTitle("Last Card", for: .normal) }

If you want the full information of the language, then remove ?.prefex(2)

Draw horizontal rule in React Native

I was able to draw a separator with flexbox properties even with a text in the center of line.

<View style={{flexDirection: 'row', alignItems: 'center'}}>
  <View style={{flex: 1, height: 1, backgroundColor: 'black'}} />
    <Text style={{width: 50, textAlign: 'center'}}>Hello</Text>
  <View style={{flex: 1, height: 1, backgroundColor: 'black'}} />

enter image description here

Counter increment in Bash loop not working

There were two conditions that caused the expression ((var++)) to fail for me:

  1. If I set bash to strict mode (set -euo pipefail) and if I start my increment at zero (0).

  2. Starting at one (1) is fine but zero causes the increment to return "1" when evaluating "++" which is a non-zero return code failure in strict mode.

I can either use ((var+=1)) or var=$((var+1)) to escape this behavior

What are the different NameID format used for?

It is just a hint for the Service Provider on what to expect from the NameID returned by the Identity Provider. It can be:

  1. unspecified
  2. emailAddress – e.g. [email protected]
  3. X509SubjectName – e.g. CN=john,O=Company Ltd.,C=US
  4. WindowsDomainQualifiedName – e.g. CompanyDomain\John
  5. kerberos– e.g. john@realm
  6. entity – this one in used to identify entities that provide SAML-based services and looks like a URI
  7. persistent – this is an opaque service-specific identifier which must include a pseudo-random value and must not be traceable to the actual user, so this is a privacy feature.
  8. transient – opaque identifier which should be treated as temporary.

POST data to a URL in PHP

Your question is not particularly clear, but in case you want to send POST data to a url without using a form, you can use either fsockopen or curl.

Here's a pretty good walkthrough of both

How to delete a whole folder and content?

There is a lot of answers, but I decided to add my own, because it's little different. It's based on OOP ;)

I created class DirectoryCleaner, which help me each time when I need to clean some directory.

public class DirectoryCleaner {
    private final File mFile;

    public DirectoryCleaner(File file) {
        mFile = file;

    public void clean() {
        if (null == mFile || !mFile.exists() || !mFile.isDirectory()) return;
        for (File file : mFile.listFiles()) {

    private void delete(File file) {
        if (file.isDirectory()) {
            for (File child : file.listFiles()) {


It can be used to solve this problem in next way:

File dir = new File(Environment.getExternalStorageDirectory(), "your_directory_name");
new DirectoryCleaner(dir).clean();

Ternary operator in PowerShell

I too, looked for a better answer, and while the solution in Edward's post is "ok", I came up with a far more natural solution in this blog post

Short and sweet:

# ---------------------------------------------------------------------------
# Name:   Invoke-Assignment
# Alias:  =
# Author: Garrett Serack (@FearTheCowboy)
# Desc:   Enables expressions like the C# operators: 
#         Ternary: 
#             <condition> ? <trueresult> : <falseresult> 
#             e.g. 
#                status = (age > 50) ? "old" : "young";
#         Null-Coalescing 
#             <value> ?? <value-if-value-is-null>
#             e.g.
#                name = GetName() ?? "No Name";
# Ternary Usage:  
#         $status == ($age > 50) ? "old" : "young"
# Null Coalescing Usage:
#         $name = (get-name) ? "No Name" 
# ---------------------------------------------------------------------------

# returns the evaluated value of the parameter passed in, 
# executing it, if it is a scriptblock   
function eval($item) {
    if( $item -ne $null ) {
        if( $item -is "ScriptBlock" ) {
            return & $item
        return $item
    return $null

# an extended assignment function; implements logic for Ternarys and Null-Coalescing expressions
function Invoke-Assignment {
    if( $args ) {
        # ternary
        if ($p = [array]::IndexOf($args,'?' )+1) {
            if (eval($args[0])) {
                return eval($args[$p])
            return eval($args[([array]::IndexOf($args,':',$p))+1]) 

        # null-coalescing
        if ($p = ([array]::IndexOf($args,'??',$p)+1)) {
            if ($result = eval($args[0])) {
                return $result
            return eval($args[$p])

        # neither ternary or null-coalescing, just a value  
        return eval($args[0])
    return $null

# alias the function to the equals sign (which doesn't impede the normal use of = )
set-alias = Invoke-Assignment -Option AllScope -Description "FearTheCowboy's Invoke-Assignment."

Which makes it easy to do stuff like (more examples in blog post):

$message == ($age > 50) ? "Old Man" :"Young Dude" 

Spring @Transactional - isolation, propagation

You can use like this:

@Transactional(propagation = Propagation.REQUIRES_NEW)
public EventMessage<ModificaOperativitaRapporto> activate(EventMessage<ModificaOperativitaRapporto> eventMessage) {
//here some transaction related code

You can use this thing also:

public interface TransactionStatus extends SavepointManager {
    boolean isNewTransaction();
    boolean hasSavepoint();
    void setRollbackOnly();
    boolean isRollbackOnly();
    void flush();
    boolean isCompleted();

Toggle show/hide on click with jQuery

You can use .toggle() function instead of .click()....

How to draw an empty plot?

You need a new plot window, and also a coordinate system, so you need and plot.window(), then you can start to add graph elements: )
plot.window( xlim=c(-5,5), ylim=c(-5,5) )

points( rnorm(100), rnorm(100) )
axis( side=1 )

example plot

How to get the full url in Express?

make effective must have two condition when Express behind proxies:

  1. app.set('trust proxy', 'loopback'); in app.js
  2. X-Forwarded-Host header must specified by you own in webserver. eg. apache, nginx


server {
    listen myhost:80;
    server_name  myhost;
    location / {
        root /path/to/myapp/public;
        proxy_set_header X-Forwarded-Host $host:$server_port;
        proxy_set_header X-Forwarded-Server $host;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_pass http://myapp:8080;


<VirtualHost myhost:80>
    ServerName myhost
    DocumentRoot /path/to/myapp/public
    ProxyPass / http://myapp:8080/
    ProxyPassReverse / http://myapp:8080/

Set a default parameter value for a JavaScript function

Yes, using default parameters is fully supported in ES6:

function read_file(file, delete_after = false) {
  // Code


const read_file = (file, delete_after = false) => {
    // Code

but prior in ES5 you could easily do this:

function read_file(file, delete_after) {
  var df = delete_after || false;
  // Code

Which means if the value is there, use the value, otherwise, use the second value after || operation which does the same thing...

Note: also there is a big difference between those if you pass a value to ES6 one even the value be falsy, that will be replaced with new value, something like null or ""... but ES5 one only will be replaced if only the passed value is truthy, that's because the way || working...

Add x and y labels to a pandas plot

what about ...

import pandas as pd
import matplotlib.pyplot as plt

values = [[1,2], [2,5]]

df2 = pd.DataFrame(values, columns=['Type A', 'Type B'], index=['Index 1','Index 2'])

          title='Video streaming dropout by category')
    .set(xlabel='x axis',
         ylabel='y axis'))

AngularJS format JSON string output

If you are looking to render JSON as HTML and it can be collapsed/opened, you can use this directive that I just made to render it nicely:

enter image description here

Apache Cordova - uninstall globally

Super late here and I still couldn't uninstall using sudo as the other answers suggest. What did it for me was checking where cordova was installed by running

which cordova

it will output something like this


then removing by

rm -rf /usr/local/bin/cordova

What is the point of "Initial Catalog" in a SQL Server connection string?

This is the initial database of the data source when you connect.

Edited for clarity:

If you have multiple databases in your SQL Server instance and you don't want to use the default database, you need some way to specify which one you are going to use.

How to JUnit test that two List<E> contain the same elements in the same order?

assertTrue()/assertFalse() : to use only to assert boolean result returned

assertTrue(Iterables.elementsEqual(argumentComponents, returnedComponents));

You want to use Assert.assertTrue() or Assert.assertFalse() as the method under test returns a boolean value.
As the method returns a specific thing such as a List that should contain some expected elements, asserting with assertTrue() in this way : Assert.assertTrue(myActualList.containsAll(myExpectedList) is an anti pattern.
It makes the assertion easy to write but as the test fails, it also makes it hard to debug because the test runner will only say to you something like :

expected true but actual is false

Assert.assertEquals(Object, Object) in JUnit4 or Assertions.assertIterableEquals(Iterable, Iterable) in JUnit 5 : to use only as both equals() and toString() are overrided for the classes (and deeply) of the compared objects

It matters because the equality test in the assertion relies on equals() and the test failure message relies on toString() of the compared objects.
As String overrides both equals() and toString(), it is perfectly valid to assert the List<String> with assertEquals(Object,Object). And about this matter : you have to override equals() in a class because it makes sense in terms of object equality, not only to make assertions easier in a test with JUnit.
To make assertions easier you have other ways (that you can see in the next points of the answer).

Is Guava a way to perform/build unit test assertions ?

Is Google Guava Iterables.elementsEqual() the best way, provided I have the library in my build path, to compare those two lists?

No it is not. Guava is not an library to write unit test assertions.
You don't need it to write most (all I think) of unit tests.

What's the canonical way to compare lists for unit tests?

As a good practice I favor assertion/matcher libraries.

I cannot encourage JUnit to perform specific assertions because this provides really too few and limited features : it performs only an assertion with a deep equals.
Sometimes you want to allow any order in the elements, sometimes you want to allow that any elements of the expected match with the actual, and so for...

So using a unit test assertion/matcher library such as Hamcrest or AssertJ is the correct way.
The actual answer provides a Hamcrest solution. Here is a AssertJ solution.

org.assertj.core.api.ListAssert.containsExactly() is what you need : it verifies that the actual group contains exactly the given values and nothing else, in order as stated :

Verifies that the actual group contains exactly the given values and nothing else, in order.

Your test could look like :

import org.assertj.core.api.Assertions;
import org.junit.jupiter.api.Test;

void ofComponent_AssertJ() throws Exception {
   MyObject myObject = MyObject.ofComponents("One", "Two", "Three");
             .containsExactly("One", "Two", "Three");

A AssertJ good point is that declaring a List as expected is needless : it makes the assertion straighter and the code more readable :

         .containsExactly("One", "Two", "Three");

And if the test fails :

// Fail : Three was not expected 
          .containsExactly("One", "Two");

you get a very clear message such as :



<["One", "Two", "Three"]>

to contain exactly (and in same order):

<["One", "Two"]>

but some elements were not expected:


Assertion/matcher libraries are a must because these will really further

Suppose that MyObject doesn't store Strings but Foos instances such as :

public class MyFooObject {

    private List<Foo> values;
    public static MyFooObject ofComponents(Foo... values) {
        // ...

    public List<Foo> getComponents(){
        return new ArrayList<>(values);

That is a very common need. With AssertJ the assertion is still simple to write. Better you can assert that the list content are equal even if the class of the elements doesn't override equals()/hashCode() while JUnit ways require that :

import org.assertj.core.api.Assertions;
import static org.assertj.core.groups.Tuple.tuple;
import org.junit.jupiter.api.Test;

void ofComponent() throws Exception {
    MyFooObject myObject = MyFooObject.ofComponents(new Foo(1, "One"), new Foo(2, "Two"), new Foo(3, "Three"));

              .extracting(Foo::getId, Foo::getName)
              .containsExactly(tuple(1, "One"),
                               tuple(2, "Two"),
                               tuple(3, "Three"));

Which equals operator (== vs ===) should be used in JavaScript comparisons?

I tested this in Firefox with Firebug using code like this:

var n = 0;
while (true) {
  if (n == 100000)


var n = 0;
while (true) {
  if (n === 100000)

My results (tested five times each and averaged):

==: 115.2
===: 114.4

So I'd say that the miniscule difference (this is over 100000 iterations, remember) is negligible. Performance isn't a reason to do ===. Type safety (well, as safe as you're going to get in JavaScript), and code quality is.

<button> vs. <input type="button" />. Which to use?

This article seems to offer a pretty good overview of the difference.

From the page:

Buttons created with the BUTTON element function just like buttons created with the INPUT element, but they offer richer rendering possibilities: the BUTTON element may have content. For example, a BUTTON element that contains an image functions like and may resemble an INPUT element whose type is set to “image”, but the BUTTON element type allows content.

The Button Element - W3C

Getting the current date in SQL Server?


Returns the current date with the time part removed.

DATETIMEs are not "stored in the following format". They are stored in a binary format.


The display format in the question is independent of storage.

Formatting into a particular display format should be done by your application.

How to resize images proportionally / keeping the aspect ratio?

$('#productThumb img').each(function() {
    var maxWidth = 140; // Max width for the image
    var maxHeight = 140;    // Max height for the image
    var ratio = 0;  // Used for aspect ratio
    var width = $(this).width();    // Current image width
    var height = $(this).height();  // Current image height
    // Check if the current width is larger than the max
    if(width > height){
        height = ( height / width ) * maxHeight;

    } else if(height > width){
        maxWidth = (width/height)* maxWidth;
    $(this).css("width", maxWidth); // Set new width
    $(this).css("height", maxHeight);  // Scale height based on ratio

How can get the text of a div tag using only javascript (no jQuery)

You'll probably want to try textContent instead of innerHTML.

Given innerHTML will return DOM content as a String and not exclusively the "text" in the div. It's fine if you know that your div contains only text but not suitable if every use case. For those cases, you'll probably have to use textContent instead of innerHTML

For example, considering the following markup:

<div id="test">
  Some <span class="foo">sample</span> text.

You'll get the following result:

var node = document.getElementById('test'),

htmlContent = node.innerHTML,
// htmlContent = "Some <span class="foo">sample</span> text."

textContent = node.textContent;
// textContent = "Some sample text."

See MDN for more details:

What's the best practice for putting multiple projects in a git repository?

While most people will tell you to just use multiple repositories, I feel it's worth mentioning there are other solutions.

Solution 1

A single repository can contain multiple independent branches, called orphan branches. Orphan branches are completely separate from each other; they do not share histories.

git checkout --orphan BRANCHNAME

This creates a new branch, unrelated to your current branch. Each project should be in its own orphaned branch.

Now for whatever reason, git needs a bit of cleanup after an orphan checkout.

rm .git/index
rm -r *

Make sure everything is committed before deleting

Once the orphan branch is clean, you can use it normally.

Solution 2

Avoid all the hassle of orphan branches. Create two independent repositories, and push them to the same remote. Just use different branch names for each repo.

# repo 1
git push origin master:master-1

# repo 2
git push origin master:master-2

.htaccess rewrite subdomain to directory

You can use the following rule in .htaccess to rewrite a subdomain to a subfolder:

RewriteEngine On

 # If the host is ""
 RewriteCond %{HTTP_HOST} ^$ [NC]
 # Then rewrite any request to /folder
 RewriteRule ^((?!folder).*)$ /folder/$1 [NC,L]

Line-by-line explanation:

  RewriteEngine on

The line above tells the server to turn on the engine for rewriting URLs.

  RewriteCond %{HTTP_HOST} ^$ [NC]

This line is a condition for the RewriteRule where we match against the HTTP host using a regex pattern. The condition says that if the host is then execute the rule.

 RewriteRule ^((?!folder).*)$ /folder/$1 [NC,L]

The rule matches and internally redirects it to

Replace with your subdomain and folder with name of the folder you want to point your subdomain to.

Is there a program to decompile Delphi?

I don't think there are any machine code decompilers that produce Pascal code. Most "Delphi decompilers" parse form and RTTI data, but do not actually decompile the machine code. I can only recommend using something like DeDe (or similar software) to extract symbol information in combination with a C decompiler, then translate the decompiled C code to Delphi (there are many source code converters out there).

HighCharts Hide Series Name from the Legend

showInLegend is a series-specific option that can hide the series from the legend. If the requirement is to hide the legends completely then it is better to use enabled: false property as shown below:

legend: { enabled: false }

More information about legend is here

Call static method with reflection

You could really, really, really optimize your code a lot by paying the price of creating the delegate only once (there's also no need to instantiate the class to call an static method). I've done something very similar, and I just cache a delegate to the "Run" method with the help of a helper class :-). It looks like this:

static class Indent{    
     public static void Run(){
         // implementation
     // other helper methods

static class MacroRunner {

    static MacroRunner() {

    static void BuildMacroRunnerList() {
        macroRunners = System.Reflection.Assembly.GetExecutingAssembly()
            .Where(x => x.Namespace.ToUpper().Contains("MACRO"))
            .Select(t => (Action)Delegate.CreateDelegate(
                t.GetMethod("Run", System.Reflection.BindingFlags.Static | System.Reflection.BindingFlags.Public)))

    static List<Action> macroRunners;

    public static void Run() {
        foreach(var run in macroRunners)

It is MUCH faster this way.

If your method signature is different from Action you could replace the type-casts and typeof from Action to any of the needed Action and Func generic types, or declare your Delegate and use it. My own implementation uses Func to pretty print objects:

static class PrettyPrinter {

    static PrettyPrinter() {

    static void BuildPrettyPrinterList() {
        printers = System.Reflection.Assembly.GetExecutingAssembly()
            .Where(x => x.Name.EndsWith("PrettyPrinter"))
            .Select(t => (Func<object, string>)Delegate.CreateDelegate(
                typeof(Func<object, string>), 
                t.GetMethod("Print", System.Reflection.BindingFlags.Static | System.Reflection.BindingFlags.Public)))

    static List<Func<object, string>> printers;

    public static void Print(object obj) {
        foreach(var printer in printers)

Explanation of polkitd Unregistered Authentication Agent

I found this problem too. Because centos service depend on for none desktop Cenots 7.2. so I delete from my .service file. It had missed.

How to put two divs side by side

Have a look at CSS and HTML in depth you will figure this out. It just floating the boxes left and right and those boxes need to be inside a same div. might be a good resource.

How to replace existing value of ArrayList element in Java

Use the set method to replace the old value with a new one.

list.set( 2, "New" );

Convert UTC datetime string to local datetime

Here's a resilient method that doesn't depend on any external libraries:

from datetime import datetime
import time

def datetime_from_utc_to_local(utc_datetime):
    now_timestamp = time.time()
    offset = datetime.fromtimestamp(now_timestamp) - datetime.utcfromtimestamp(now_timestamp)
    return utc_datetime + offset

This avoids the timing issues in DelboyJay's example. And the lesser timing issues in Erik van Oosten's amendment.

As an interesting footnote, the timezone offset computed above can differ from the following seemingly equivalent expression, probably due to daylight savings rule changes:

offset = datetime.fromtimestamp(0) - datetime.utcfromtimestamp(0) # NO!

Update: This snippet has the weakness of using the UTC offset of the present time, which may differ from the UTC offset of the input datetime. See comments on this answer for another solution.

To get around the different times, grab the epoch time from the time passed in. Here's what I do:

def utc2local (utc):
    epoch = time.mktime(utc.timetuple())
    offset = datetime.fromtimestamp (epoch) - datetime.utcfromtimestamp (epoch)
    return utc + offset

How to get all key in JSON object (javascript)

ES6 of the day here;

const json_getAllKeys = data => (
  data.reduce((keys, obj) => (
    keys.concat(Object.keys(obj).filter(key => (
      keys.indexOf(key) === -1))
  ), [])

And yes it can be written in very long one line;

const json_getAllKeys = data => data.reduce((keys, obj) => keys.concat(Object.keys(obj).filter(key => keys.indexOf(key) === -1)), [])

EDIT: Returns all first order keys if the input is of type array of objects

to call onChange event after pressing Enter key

According to React Doc, you could listen to keyboard events, like onKeyPress or onKeyUp, not onChange.

var Input = React.createClass({
  render: function () {
    return <input type="text" onKeyDown={this._handleKeyDown} />;
  _handleKeyDown: function(e) {
    if (e.key === 'Enter') {
      console.log('do validate');

Update: Use React.Component

Here is the code using React.Component which does the same thing

class Input extends React.Component {
  _handleKeyDown = (e) => {
    if (e.key === 'Enter') {
      console.log('do validate');

  render() {
    return <input type="text" onKeyDown={this._handleKeyDown} />

Here is the jsfiddle.

Update 2: Use a functional component

const Input = () => {
  const handleKeyDown = (event) => {
    if (event.key === 'Enter') {
      console.log('do validate')

  return <input type="text" onKeyDown={handleKeyDown} />

bootstrap.min.js:6 Uncaught Error: Bootstrap dropdown require Popper.js

On moving a .html template to a wordpress one, I found this "popper required" popping up regularly :)

Two reasons it happened for me: and the console error can be deceptive:

  1. The error in the console can send you down the wrong path. It MIGHT not be the real issue. First reason for me was the order in which you have set your .js files to load. In html easy, put them in the same order as the theme template. In Wordpress, you need to enqueue them in the right order, but also set a priority if they don't appear in the right order,

  2. Second thing is are the .js files in the header or the footer. Moving them to the footer can solve the issue - it did for me, after a day of trying to debug the issue. Usually doesn't matter, but for a complex page with lots of js libraries, it might!

how to pass data in an hidden field from one jsp page to another?

The code from Alex works great. Just note that when you use request.getParameter you must use a request dispatcher

//Pass results back to the client
RequestDispatcher dispatcher =   getServletContext().getRequestDispatcher("TestPages/ServiceServlet.jsp");
dispatcher.forward(request, response);

Create file path from variables

You can also use an object-oriented path with pathlib (available as a standard library as of Python 3.4):

from pathlib import Path

start_path = Path('/my/root/directory')
final_path = start_path / 'in' / 'here'

Git diff says subproject is dirty

git submodule foreach --recursive git checkout .

This didn't do the trick for me but it gave me a list of files (in my case only one) that had been changed in the submodule (without me doing anything there).

So I could head over to the submodule and git status showed me that my HEAD was detached -> git checkout master, git status to see the modified file once again, git checkout >filename<, git pull and everything fine again.

How to properly add include directories with CMake

Two things must be done.

First add the directory to be included:

target_include_directories(test PRIVATE ${YOUR_DIRECTORY})

In case you are stuck with a very old CMake version (2.8.10 or older) without support for target_include_directories, you can also use the legacy include_directories instead:


Then you also must add the header files to the list of your source files for the current target, for instance:

set(SOURCES file.cpp file2.cpp ${YOUR_DIRECTORY}/file1.h ${YOUR_DIRECTORY}/file2.h)
add_executable(test ${SOURCES})

This way, the header files will appear as dependencies in the Makefile, and also for example in the generated Visual Studio project, if you generate one.

How to use those header files for several targets:


add_library(mylib libsrc.cpp ${HEADER_FILES})
target_include_directories(mylib PRIVATE ${YOUR_DIRECTORY})
add_executable(myexec execfile.cpp ${HEADER_FILES})
target_include_directories(myexec PRIVATE ${YOUR_DIRECTORY})

I want to get the type of a variable at runtime

So, strictly speaking, the "type of a variable" is always present, and can be passed around as a type parameter. For example:

val x = 5
def f[T](v: T) = v
f(x) // T is Int, the type of x

But depending on what you want to do, that won't help you. For instance, may want not to know what is the type of the variable, but to know if the type of the value is some specific type, such as this:

val x: Any = 5
def f[T](v: T) = v match {
  case _: Int    => "Int"
  case _: String => "String"
  case _         => "Unknown"

Here it doesn't matter what is the type of the variable, Any. What matters, what is checked is the type of 5, the value. In fact, T is useless -- you might as well have written it def f(v: Any) instead. Also, this uses either ClassTag or a value's Class, which are explained below, and cannot check the type parameters of a type: you can check whether something is a List[_] (List of something), but not whether it is, for example, a List[Int] or List[String].

Another possibility is that you want to reify the type of the variable. That is, you want to convert the type into a value, so you can store it, pass it around, etc. This involves reflection, and you'll be using either ClassTag or a TypeTag. For example:

val x: Any = 5
import scala.reflect.ClassTag
def f[T](v: T)(implicit ev: ClassTag[T]) = ev.toString
f(x) // returns the string "Any"

A ClassTag will also let you use type parameters you received on match. This won't work:

def f[A, B](a: A, b: B) = a match {
  case _: B => "A is a B"
  case _ => "A is not a B"

But this will:

val x = 'c'
val y = 5
val z: Any = 5
import scala.reflect.ClassTag
def f[A, B: ClassTag](a: A, b: B) = a match {
  case _: B => "A is a B"
  case _ => "A is not a B"
f(x, y) // A (Char) is not a B (Int)
f(x, z) // A (Char) is a B (Any)

Here I'm using the context bounds syntax, B : ClassTag, which works just like the implicit parameter in the previous ClassTag example, but uses an anonymous variable.

One can also get a ClassTag from a value's Class, like this:

val x: Any = 5
val y = 5
import scala.reflect.ClassTag
def f(a: Any, b: Any) = {
  val B = ClassTag(b.getClass)
  ClassTag(a.getClass) match {
    case B => "a is the same class as b"
    case _ => "a is not the same class as b"
f(x, y) == f(y, x) // true, a is the same class as b

A ClassTag is limited in that it only covers the base class, but not its type parameters. That is, the ClassTag for List[Int] and List[String] is the same, List. If you need type parameters, then you must use a TypeTag instead. A TypeTag however, cannot be obtained from a value, nor can it be used on a pattern match, due to JVM's erasure.

Examples with TypeTag can get quite complex -- not even comparing two type tags is not exactly simple, as can be seen below:

import scala.reflect.runtime.universe.TypeTag
def f[A, B](a: A, b: B)(implicit evA: TypeTag[A], evB: TypeTag[B]) = evA == evB
type X = Int
val x: X = 5
val y = 5
f(x, y) // false, X is not the same type as Int

Of course, there are ways to make that comparison return true, but it would require a few book chapters to really cover TypeTag, so I'll stop here.

Finally, maybe you don't care about the type of the variable at all. Maybe you just want to know what is the class of a value, in which case the answer is rather simple:

val x = 5
x.getClass // int -- technically, an Int cannot be a class, but Scala fakes it

It would be better, however, to be more specific about what you want to accomplish, so that the answer can be more to the point.

Expected response code 220 but got code "", with message "" in Laravel

i was facing this problem and i checked all the answers and nothing worked for me, but then i reset mail.php and didn't touch it and set the mail server from .env file and it worked perfectly, hope this will save the time for someone :).

How to push a docker image to a private repository

Simple working solution:

Go here to create a PRIVATE repository with name for example johnsmith/private-repository this is the NAME/REPOSITORY you will use for your image when building the image.

  • First, docker login

  • Second, I use "docker build -t johnsmith/private-repository:01 ." (where 01 is my version name) to create image, and I use "docker images" to confirm the image created such as in this yellow box below: (sorry I can not paste the table format but the text string only)

johnsmith/private-repository(REPOSITORY) 01(TAG) c5f4a2861d6e(IMAGE ID) 2 days ago(CREATED) 305MB(SIZE)


Sass .scss: Nesting and multiple classes?

Use &


.container {

    &.hello {

How to take character input in java

I had the same struggle and I this is what I used:

} public static void main(String[] args) {

Scanner scan = new Scanner(;
System.out.print("Please enter the string: ");
String input =;
System.out.print("Please enter the required symbol: ");
String symbol =;        
char symbolChar = symbol.charAt(0);

This works just fine. The idea is to get from the string the only char in it.

How to check if a registry value exists using C#?

For Registry Key you can check if it is null after getting it. It will be, if it doesn't exist.

For Registry Value you can get names of Values for the current key and check if this array contains the needed Value name.


public static bool checkMachineType()
    RegistryKey winLogonKey = Registry.LocalMachine.OpenSubKey(@"System\CurrentControlSet\services\pcmcia", true);
    return (winLogonKey.GetValueNames().Contains("Start"));

XmlDocument - load from string?

XmlDocument doc = new XmlDocument();

Where str is your XML string. See the MSDN article for more info.

How to add pandas data to an existing csv file?

This is how I did it in 2021

Let us say I have a csv sales.csv which has the following data in it:


Order Name,Price,Qty

and to add more rows I can load them in a data frame and append it to the csv like this:

import pandas

data = [
    ['matchstick', '60', '11'],
    ['cookies', '10', '120']
dataframe = pandas.DataFrame(data)
dataframe.to_csv("sales.csv", index=False, mode='a', header=False)

and the output will be:

Order Name,Price,Qty

PHP how to get value from array if key is in a variable

It should work the way you intended.

$array = array('value-0', 'value-1', 'value-2', 'value-3', 'value-4', 'value-5' /* … */);
$key = 4;
$value = $array[$key];
echo $value; // value-4

But maybe there is no element with the key 4. If you want to get the fiveth item no matter what key it has, you can use array_slice:

$value = array_slice($array, 4, 1);

creating json object with variables

It's called on Object Literal

I'm not sure what you want your structure to be, but according to what you have above, where you put the values in variables try this.

var formObject =  {"formObject": [
                {"firstName": firstName, "lastName": lastName},
                {"phoneNumber": phone},
                {"address": address},

Although this seems to make more sense (Why do you have an array in the above literal?):

var formObject = {
   firstName: firstName

How can I determine if a String is non-null and not only whitespace in Groovy?

You could add a method to String to make it more semantic:

String.metaClass.getNotBlank = { !delegate.allWhitespace }

which let's you do:

groovy:000> foo = ''
groovy:000> foo.notBlank
===> false
groovy:000> foo = 'foo'
===> foo
groovy:000> foo.notBlank
===> true

Pointers in C: when to use the ampersand and the asterisk?

You have pointers and values:

int* p; // variable p is pointer to integer type
int i; // integer value

You turn a pointer into a value with *:

int i2 = *p; // integer i2 is assigned with integer value that pointer p is pointing to

You turn a value into a pointer with &:

int* p2 = &i; // pointer p2 will point to the address of integer i

Edit: In the case of arrays, they are treated very much like pointers. If you think of them as pointers, you'll be using * to get at the values inside of them as explained above, but there is also another, more common way using the [] operator:

int a[2];  // array of integers
int i = *a; // the value of the first element of a
int i2 = a[0]; // another way to get the first element

To get the second element:

int a[2]; // array
int i = *(a + 1); // the value of the second element
int i2 = a[1]; // the value of the second element

So the [] indexing operator is a special form of the * operator, and it works like this:

a[i] == *(a + i);  // these two statements are the same thing

Check if element found in array c++

There are many is to use the std::find() algorithm, e.g.

#include <algorithm>

int myArray[] = { 3, 2, 1, 0, 1, 2, 3 };
size_t myArraySize = sizeof(myArray) / sizeof(int);
int *end = myArray + myArraySize;
// find the value 0:
int *result = std::find(myArray, end, 0);
if (result != end) {
  // found value at "result" pointer location...

uppercase first character in a variable with bash

What if the first character is not a letter (but a tab, a space, and a escaped double quote)? We'd better test it until we find a letter! So:

S='  \"ó foo bar\"'
until [[ ${S:$N:1} =~ [[:alpha:]] ]]; do N=$[$N+1]; done
#F=`echo ${S:$N:1} | tr [:lower:] [:upper:]`
#F=`echo ${S:$N:1} | sed -E -e 's/./\u&/'` #other option
F=`echo ${S:$N:1}
F=`echo ${F} #pure Bash solution to "upper"
echo "$F"${S:(($N+1))} #without garbage
echo '='${S:0:(($N))}"$F"${S:(($N+1))}'=' #garbage preserved

Foo bar
= \"Foo bar=

angularjs to output plain text instead of html

Use ng-bind-html this is only proper and simplest way

How do disable paging by swiping with finger in ViewPager but still be able to swipe programmatically?

Better to declare it styleable, so you can change its property from xml:

private boolean swipeable;

public MyViewPager(Context context, AttributeSet attrs) {
    super(context, attrs);
    TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.MyViewPager);
    try {
        swipeable = a.getBoolean(R.styleable.MyViewPager_swipeable, true);
    } finally {

public boolean onInterceptTouchEvent(MotionEvent event) {
    return swipeable ? super.onInterceptTouchEvent(event) : false;

public boolean onTouchEvent(MotionEvent event) {
    return swipeable ? super.onTouchEvent(event) : false;

And in your values/attr.xml:

<declare-styleable name="MyViewPager">
  <attr name="swipeable" format="boolean" />

so that you can use it in you layout xml:

    app:swipeable="false" />

Of course, you can still have a get/set property.

JavaScript: replace last occurrence of text in a string

Thought I'd answer here since this came up first in my Google search and there's no answer (outside of Matt's creative answer :)) that generically replaces the last occurrence of a string of characters when the text to replace might not be at the end of the string.

if (!String.prototype.replaceLast) {
    String.prototype.replaceLast = function(find, replace) {
        var index = this.lastIndexOf(find);

        if (index >= 0) {
            return this.substring(0, index) + replace + this.substring(index + find.length);

        return this.toString();

var str = 'one two, one three, one four, one';

// outputs: one two, one three, one four, finish
console.log(str.replaceLast('one', 'finish'));

// outputs: one two, one three, one four; one
console.log(str.replaceLast(',', ';'));

Convert string in base64 to image and save on filesystem in Python

If you are trying to decode a web image you can simply use this :

import base64

with open("imageToSave.png", "wb") as fh:

data => is the encoded string

It will take care of the padding errors

Converting Float to Dollars and Cents

In Python 3.x and 2.7, you can simply do this:

>>> '${:,.2f}'.format(1234.5)

The :, adds a comma as a thousands separator, and the .2f limits the string to two decimal places (or adds enough zeroes to get to 2 decimal places, as the case may be) at the end.

Using jQuery to programmatically click an <a> link

Try this for compatibility;

<script type="text/javascript">
        $(function() {
            setTimeout(function() {
                window.location.href = $('#myAnchor').attr("href");

            }, 1500);

How to install latest version of openssl Mac OS X El Capitan

I reached this page when I searched for information about openssl being keg-only. I believe I have understood the reason why Homebrew is taking this action now. My solution may work for you:

  • Use the following command to make the new openssl command available (assuming you have adjusted PATH to put /usr/local/bin before /usr/bin): ln -s /usr/local/opt/openssl/bin/openssl /usr/local/bin/

  • When compiling with openssl, follow Homebrew's advice and use -I/usr/local/opt/openssl/include -L/usr/local/opt/openssl/lib

  • Alternatively, you can make these settings permanent by putting the following lines in your .bash_profile or .bashrc: export CPATH=/usr/local/opt/openssl/include export LIBRARY_PATH=/usr/local/opt/openssl/lib

Reading images in python

If you just want to read an image in Python using the specified libraries only, I will go with matplotlib

In matplotlib :

import matplotlib.image
read_img = matplotlib.image.imread('your_image.png')

Android ADB device offline, can't issue commands

Worked for me: in the begining it worked and after a while went to offline. I did the follwong: adb kill-server adb start-server. Plug the phone again with usb to PC adb devices, output of empty list provided. adb tcpip 5555, adb connect <mobile wifi ip address> Then it became online again.

How to solve "Kernel panic - not syncing - Attempted to kill init" -- without erasing any user data

At grub screen goto boot in recovery.

As booting hold ESC

It should take you into a gui menu. Open command and fix selinux.

Also I suggest run the clean broken packages

Swift extract regex matches

update @Mike Chirico's to Swift 5

extension String{

  func regex(pattern: String) -> [String]?{
    do {
        let regex = try NSRegularExpression(pattern: pattern, options: NSRegularExpression.Options(rawValue: 0))
        let all = NSRange(location: 0, length: count)
        var matches = [String]()
        regex.enumerateMatches(in: self, options: NSRegularExpression.MatchingOptions(rawValue: 0), range: all) {
            (result : NSTextCheckingResult?, _, _) in
              if let r = result {
                    let nsstr = self as NSString
                    let result = nsstr.substring(with: r.range) as String
        return matches
    } catch {
        return nil

Creating the checkbox dynamically using JavaScript?

You can create a function:

function changeInputType(oldObj, oTyp, nValue) {
  var newObject = document.createElement('input');
  newObject.type = oTyp;
  if(oldObj.size) newObject.size = oldObj.size;
  if(oldObj.value) newObject.value = nValue;
  if( =;
  if( =;
  if(oldObj.className) newObject.className = oldObj.className;
  return newObject;

And you do a call like:

changeInputType(document.getElementById('DATE_RANGE_VALUE'), 'checkbox', 7);

Java 6 Unsupported major.minor version 51.0

That version number (51.0) indicates that you are trying to run classes compiled for Java 7. You will need to recompile them for Java 6.

Note, however, that some features may no longer be compatible with Java 6, which is very old, and no longer (publicly) supported by Oracle.

How to download the latest artifact from Artifactory repository?

This may be new:[RELEASE]/foo-1.0.[RELEASE].tgz

For loading module foo from . Keep the [RELEASE] parts verbatim. This is mentioned in the docs but it's not made abundantly clear that you can actually put [RELEASE] into the URL (as opposed to a substitution pattern for the developer).

row-level trigger vs statement-level trigger

1)row level trigger is used to perform action on set of rows as insert , update or delete

example:-you have to delete a set of rows and simultaneously that deleted rows must also inserted in new table for audit purpose;

2)statement level trigger:- it generally used to imposed restriction on the event you are performing.

example:- restriction to delete the data between 10 pm and 6 am;

hope this helps:)

Angular 5, HTML, boolean on checkbox is checked

Here is my answer,

In row.model.ts

export interface Row {
   otherProperty : type;
   checked : bool;
   otherProperty : type;

In .html

<tr class="even" *ngFor="let item of rows">
   <input [checked]="item.checked" type="checkbox">

In .ts

rows : Row[] = [];

update the rows in component.ts

Difference between innerText, innerHTML and value?

The innerText property returns the actual text value of an html element while the innerHTML returns the HTML content. Example below:

var element = document.getElementById('hello');_x000D_
element.innerText = '<strong> hello world </strong>';_x000D_
console.log('The innerText property will not parse the html tags as html tags but as normal text:\n' + element.innerText);_x000D_
console.log('The innerHTML element property will encode the html tags found inside the text of the element:\n' + element.innerHTML);_x000D_
element.innerHTML = '<strong> hello world </strong>';_x000D_
console.log('The <strong> tag we put above has been parsed using the innerHTML property so the .innerText will not show them \n ' + element.innerText);_x000D_
<p id="hello"> Hello world _x000D_

Interfaces with static fields in java for sharing 'constants'

Instead of implementing a "constants interface", in Java 1.5+, you can use static imports to import the constants/static methods from another class/interface:

import static com.kittens.kittenpolisher.KittenConstants.*;

This avoids the ugliness of making your classes implement interfaces that have no functionality.

As for the practice of having a class just to store constants, I think it's sometimes necessary. There are certain constants that just don't have a natural place in a class, so it's better to have them in a "neutral" place.

But instead of using an interface, use a final class with a private constructor. (Making it impossible to instantiate or subclass the class, sending a strong message that it doesn't contain non-static functionality/data.)


/** Set of constants needed for Kitten Polisher. */
public final class KittenConstants
    private KittenConstants() {}

    public static final String KITTEN_SOUND = "meow";
    public static final double KITTEN_CUTENESS_FACTOR = 1;

HTML&CSS + Twitter Bootstrap: full page layout or height 100% - Npx

if you use Bootstrap 2.2.1 then maybe is this what you are looking for.

Sample file index.html

<!DOCTYPE html>_x000D_
<html xmlns="">_x000D_
    <link href="Content/bootstrap.min.css" rel="stylesheet" />_x000D_
    <link href="Content/Site.css" rel="stylesheet" />_x000D_
        <div class="navbar navbar-default navbar-fixed-top">_x000D_
            <div class="container">_x000D_
                <div class="navbar-header">_x000D_
                    <button type="button" class="navbar-toggle" data-toggle="collapse" data-target=".navbar-collapse">_x000D_
                        <span class="icon-bar"></span>_x000D_
                        <span class="icon-bar"></span>_x000D_
                        <span class="icon-bar"></span>_x000D_
                    <a class="navbar-brand" href="/">Application name</a>_x000D_
                <div class="navbar-collapse collapse">_x000D_
                    <ul class="nav navbar-nav">_x000D_
                        <li><a href="/">Home</a></li>_x000D_
                        <li><a href="/Home/About">About</a></li>_x000D_
                        <li><a href="/Home/Contact">Contact</a></li>_x000D_
                    <ul class="nav navbar-nav navbar-right">_x000D_
                        <li><a href="/Account/Register" id="registerLink">Register</a></li>_x000D_
                        <li><a href="/Account/Login" id="loginLink">Log in</a></li>_x000D_
        <div class="col-md-2">_x000D_
            <a href="#" class="btn btn-block btn-info">Some Menu</a>_x000D_
            <a href="#" class="btn btn-block btn-info">Some Menu</a>_x000D_
            <a href="#" class="btn btn-block btn-info">Some Menu</a>_x000D_
            <a href="#" class="btn btn-block btn-info">Some Menu</a>_x000D_
       <div class="col-md-10">_x000D_
               <h3>Your application description page.</h3>_x000D_
               <p>Use this area to provide additional information.</p>_x000D_
               <p>Use this area to provide additional information.</p>_x000D_
               <p>Use this area to provide additional information.</p>_x000D_
               <p>Use this area to provide additional information.</p>_x000D_
               <p>Use this area to provide additional information.</p>_x000D_
               <p>Use this area to provide additional information.</p>_x000D_
               <hr />_x000D_
        <div class="navbar navbar-default navbar-fixed-bottom">_x000D_
            <div class="container" style="font-size: .8em">_x000D_
                <p class="navbar-text">_x000D_
                    &copy; Some info_x000D_
_x000D_ File Content/Site.css
body {_x000D_
    padding-bottom: 70px;_x000D_
    padding-top: 70px;_x000D_

How to merge a transparent png image with another image using PIL

Image.paste does not work as expected when the background image also contains transparency. You need to use real Alpha Compositing.

Pillow 2.0 contains an alpha_composite function that does this.

background ="test1.png")
foreground ="test2.png")

Image.alpha_composite(background, foreground).save("test3.png")

EDIT: Both images need to be of the type RGBA. So you need to call convert('RGBA') if they are paletted, etc.. If the background does not have an alpha channel, then you can use the regular paste method (which should be faster).

Best way to integrate Python and JavaScript?

Many of these projects mentioned above are dead or dying, lacking activity and interest from author side. Interesting to follow how this area develops.

For the record, in era of plugin based implementations, KDE camp had an attempt to solve this with plugin and non-language specific way and created the Kross - in my understanding it never took off even inside the community itself.

During this chicken and egg -problem time, javascript-based implementions are definately way to go. Maybe in the future we seee pure and clean, full Python support natively in browsers.

What is javax.inject.Named annotation supposed to be used for?

The primary role of the @Named annotation is to define a bean for the purpose of resolving EL statements within the application, usually through JSF EL resolvers. Injection can be performed using names but this was not how injection in CDI was meant to work since CDI gives us a much richer way to express injection points and the beans to be injected into them.

jQuery UI DatePicker to show year only

Try this piece of code, it worked for me:

    format: "yyyy",
    viewMode: "years",
    minViewMode: "years"

I hope it will do magic also for you.

Order by in Inner Join

In SQL, the order of the output is not defined unless you specify it in the ORDER BY clause.

Try this:

FROM    one
JOIN    two
ON      one.one_name = two.one_name

How to combine two byte arrays

String temp = passwordSalt;
byte[] byteSalt = temp.getBytes();
int start = 32;
for (int i = 0; i < byteData.length; i ++)
    byteData[start + i] = byteSalt[i];

The problem with your code here is that the variable i that is being used to index the arrays is going past both the byteSalt array and the byteData array. So, Make sure that byteData is dimensioned to be at least the maximum length of the passwordSalt string plus 32. What will correct it is replacing the following line:

for (int i = 0; i < byteData.length; i ++)


for (int i = 0; i < byteSalt.length; i ++)

How to edit one specific row in Microsoft SQL Server Management Studio 2008?

The menu location seems to have changed to:

Query Designer --> Pane --> SQL

Run a controller function whenever a view is opened/shown

If you have assigned a certain controller to your view, then your controller will be invoked every time your view loads. In that case, you can execute some code in your controller as soon as it is invoked, for example this way:

<ion-nav-view ng-controller="indexController" name="other" ng-init="doSomething()"></ion-nav-view>

And in your controller:

app.controller('indexController', function($scope) {
        Write some code directly over here without any function,
        and it will be executed every time your view loads.
        Something like this:
    $ = 1;

Edit: You might try to track state changes and then execute some code when the route is changed and a certain route is visited, for example:

function(event, toState, toParams, fromState, fromParams){ ... })

You can find more details here: State Change Events.

Python Threading String Arguments

from threading import Thread
from time import sleep
def run(name):
    for x in range(10):
        print("helo "+name)
def run1():
    for x in range(10):

GridLayout and Row/Column Span Woe

<RelativeLayout xmlns:android=""
    android:layout_height="fill_parent" >

        android:rowCount="7" >

            android:textSize="20dip" />

            android:textSize="20dip" />

            android:textSize="20dip" />

            android:textSize="20dip" />

            android:textSize="20dip" />

            android:textSize="20dip" />



form_for but to post to a different action

new syntax

<%= form_for :user, url: custom_user_path, method: :post do |f|%>

Redirect from web api post action

Here is another way you can get to the root of your website without hard coding the url:

var response = Request.CreateResponse(HttpStatusCode.Moved);
string fullyQualifiedUrl = Request.RequestUri.GetLeftPart(UriPartial.Authority);
response.Headers.Location = new Uri(fullyQualifiedUrl);

Note: Will only work if both your MVC website and WebApi are on the same URL

Reading a JSP variable from JavaScript

<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE html>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">

    <title>JSP Page</title>
          <% String name = "" ;%> // jsp vari
         var name = "<%=name %>" // call var to js
         $("#id").html(name); //output to html

    <h1 id='id'>!</h1>

setting min date in jquery datepicker

Just want to add this for the future programmer.

This code limits the date min and max. The year is fully controlled by getting the current year as max year.

Hope this could help to anyone.

Here's the code.

var dateToday = new Date();
var yrRange = '2014' + ":" + (dateToday.getFullYear());

$(function () {
        showOn: 'button',
        changeMonth: true,
        changeYear: true,
        showButtonPanel: true,
        buttonImageOnly: true,
        yearRange: yrRange,
        buttonImage: 'calendar3.png',
        buttonImageOnly: true,
        minDate: new Date(2014,1-1,1),
        maxDate: '+50Y',

JavaScript - Getting HTML form values

My 5 cents here, using form.elements which allows you to query each field by it's name, not only by iteration:

const form = document.querySelector('form[name="valform"]');
const ccValidation = form.elements['cctextbox'].value;
const ccType = form.elements['cardtype'].value;

Update TensorFlow

Before trying to update tensorflow try updating pip

pip install --upgrade pip

If you are upgrading from a previous installation of TensorFlow < 0.7.1, you should uninstall the previous TensorFlow and protobuf using,

pip uninstall tensorflow

to make sure you get a clean installation of the updated protobuf dependency.

Uninstall the TensorFlow on your system, and check out Download and Setup to reinstall again.

If you are using pip install, go check the available version over, search keywords with linux/cpu/tensorflow to see the availabilities.

Then, set the path for download and execute in sudo.

$ export TF_BINARY_URL=

$ sudo pip install --upgrade $TF_BINARY_URL

For more detail, follow this link in here

How to concatenate strings in twig

You can use ~ like {{ foo ~ 'inline string' ~ bar.fieldName }}

But you can also create your own concat function to use it like in your question:
{{ concat('http://', }}:

In src/AppBundle/Twig/AppExtension.php


namespace AppBundle\Twig;

class AppExtension extends \Twig_Extension
     * {@inheritdoc}
    public function getFunctions()
        return [
            new \Twig_SimpleFunction('concat', [$this, 'concat'], ['is_safe' => ['html']]),

    public function concat()
        return implode('', func_get_args())

     * {@inheritdoc}
    public function getName()
        return 'app_extension';

In app/config/services.yml:

        class: AppBundle\Twig\AppExtension
        public: false
            - { name: twig.extension }

How to get the current date/time in Java

Just create a Date object...

import java.util.Date;

Date date = new Date();

form_for with nested resources

Travis R is correct. (I wish I could upvote ya.) I just got this working myself. With these routes:

resources :articles do
  resources :comments

You get paths like:


routed to controllers at


just as it says at, with no special namespaces.

But partials and forms become tricky. Note the square brackets:

<%= form_for [@article, @comment] do |f| %>

Most important, if you want a URI, you may need something like this:

article_comment_path(@article, @comment)


[@article, @comment]

as described at

For example, inside a collections partial with comment_item supplied for iteration,

<%= link_to "delete", article_comment_path(@article, comment_item),
      :method => :delete, :confirm => "Really?" %>

What jamuraa says may work in the context of Article, but it did not work for me in various other ways.

There is a lot of discussion related to nested resources, e.g.

Interestingly, I just learned that most people's unit-tests are not actually testing all paths. When people follow jamisbuck's suggestion, they end up with two ways to get at nested resources. Their unit-tests will generally get/post to the simplest:

# POST /comments
post :create, :comment => {:article_id=>42, ...}

In order to test the route that they may prefer, they need to do it this way:

# POST /articles/42/comments
post :create, :article_id => 42, :comment => {...}

I learned this because my unit-tests started failing when I switched from this:

resources :comments
resources :articles do
  resources :comments

to this:

resources :comments, :only => [:destroy, :show, :edit, :update]
resources :articles do
  resources :comments, :only => [:create, :index, :new]

I guess it's ok to have duplicate routes, and to miss a few unit-tests. (Why test? Because even if the user never sees the duplicates, your forms may refer to them, either implicitly or via named routes.) Still, to minimize needless duplication, I recommend this:

resources :comments
resources :articles do
  resources :comments, :only => [:create, :index, :new]

Sorry for the long answer. Not many people are aware of the subtleties, I think.

How to Get the HTTP Post data in C#?

This code will list out all the form variables that are being sent in a POST. This way you can see if you have the proper names of the post values.

string[] keys = Request.Form.AllKeys;
for (int i= 0; i < keys.Length; i++) 
   Response.Write(keys[i] + ": " + Request.Form[keys[i]] + "<br>");

How to create tar.gz archive file in Windows?

tar.gz file is just a tar file that's been gzipped. Both tar and gzip are available for windows.

If you like GUIs (Graphical user interface), 7zip can pack with both tar and gzip.

Output an Image in PHP

$file = '../image.jpg';
$type = 'image/jpeg';
header('Content-Length: ' . filesize($file));

Iterating through a variable length array

for(int i = 0; i < array.length; i++)


for(String value : array)

The second version is a "for-each" loop and it works with arrays and Collections. Most loops can be done with the for-each loop because you probably don't care about the actual index. If you do care about the actual index us the first version.

Just for completeness you can do the while loop this way:

int index = 0;

while(index < myArray.length)
  final String value;

  value = myArray[index];

But you should use a for loop instead of a while loop when you know the size (and even with a variable length array you know the size... it is just different each time).

ASP.NET Web API - PUT & DELETE Verbs Not Allowed - IIS 8

Okay. I finally got to the bottom of this. You need to jump through some hoops to get the PUT and DELETE verbs working correctly with IIS8. In fact if you install the release candidate of VS 2012 and create a new WEB API project you'll find that the sample PUT and DELETE methods return 404 errors out of the box.

To use the PUT and DELETE verbs with the Web API you need to edit %userprofile%\documents\iisexpress\config\applicationhost.config and add the verbs to the ExtensionlessUrl handler as follows:

Change this line:

<add name="ExtensionlessUrl-Integrated-4.0" path="*." verb="GET,HEAD,POST,DEBUG" type="System.Web.Handlers.TransferRequestHandler" preCondition="integratedMode,runtimeVersionv4.0" />


<add name="ExtensionlessUrl-Integrated-4.0" path="*." verb="GET,HEAD,POST,DEBUG,PUT,DELETE" type="System.Web.Handlers.TransferRequestHandler" preCondition="integratedMode,runtimeVersionv4.0" />

In addition to the above you should ensure WebDAV is not interfering with your requests. This can be done by commenting out the following lines from applicationhost.config.

<add name="WebDAVModule" image="%IIS_BIN%\webdav.dll" />
<add name="WebDAVModule" /> 
<add name="WebDAV" path="*" verb="PROPFIND,PROPPATCH,MKCOL,PUT,COPY,DELETE,MOVE,LOCK,UNLOCK" modules="WebDAVModule" resourceType="Unspecified" requireAccess="None" />

Also be aware that the default Web API convention is that your method name should be the same as the invoked HTTP verb. For example if you're sending an HTTP delete request your method, by default, should be named Delete.

Vue.js data-bind style backgroundImage not working

I tried @david answer, and it didn't fix my issue. after a lot of hassle, I made a method and return the image with style string.


<div v-for="slide in loadSliderImages" :key="">
    <div v-else :style="bannerBgImage(slide.banner)"></div>


    return 'background-image: url("' + image + '")';

Check if the number is integer

Reading the R language documentation, as.integer has more to do with how the number is stored than if it is practically equivalent to an integer. is.integer tests if the number is declared as an integer. You can declare an integer by putting a L after it.

> is.integer(66L)
[1] TRUE
> is.integer(66)

Also functions like round will return a declared integer, which is what you are doing with x==round(x). The problem with this approach is what you consider to be practically an integer. The example uses less precision for testing equivalence.

> is.wholenumber(1+2^-50)
[1] TRUE
> check.integer(1+2^-50)

So depending on your application you could get into trouble that way.

What is newline character -- '\n'

NewLine (\n) is 10 (0xA) and CarriageReturn (\r) is 13 (0xD).

Different operating systems picked different end of line representations for files. Windows uses CRLF (\r\n). Unix uses LF (\n). Older Mac OS versions use CR (\r), but OS X switched to the Unix character.

Here is a relatively useful FAQ.

Modifying a subset of rows in a pandas dataframe

To replace multiples columns convert to numpy array using .values:

df.loc[df.A==0, ['B', 'C']] = df.loc[df.A==0, ['B', 'C']].values / 2

svn cleanup: sqlite: database disk image is malformed

The SVN cleanup didn't work. The SVN folder on my local system got corrupted. So I just deleted the folder, recreated a new one, and updated from SVN. That solved the problem!

"static const" vs "#define" vs "enum"

It depends on what you need the value for. You (and everyone else so far) omitted the third alternative:

  1. static const int var = 5;
  2. #define var 5
  3. enum { var = 5 };

Ignoring issues about the choice of name, then:

  • If you need to pass a pointer around, you must use (1).
  • Since (2) is apparently an option, you don't need to pass pointers around.
  • Both (1) and (3) have a symbol in the debugger's symbol table - that makes debugging easier. It is more likely that (2) will not have a symbol, leaving you wondering what it is.
  • (1) cannot be used as a dimension for arrays at global scope; both (2) and (3) can.
  • (1) cannot be used as a dimension for static arrays at function scope; both (2) and (3) can.
  • Under C99, all of these can be used for local arrays. Technically, using (1) would imply the use of a VLA (variable-length array), though the dimension referenced by 'var' would of course be fixed at size 5.
  • (1) cannot be used in places like switch statements; both (2) and (3) can.
  • (1) cannot be used to initialize static variables; both (2) and (3) can.
  • (2) can change code that you didn't want changed because it is used by the preprocessor; both (1) and (3) will not have unexpected side-effects like that.
  • You can detect whether (2) has been set in the preprocessor; neither (1) nor (3) allows that.

So, in most contexts, prefer the 'enum' over the alternatives. Otherwise, the first and last bullet points are likely to be the controlling factors — and you have to think harder if you need to satisfy both at once.

If you were asking about C++, then you'd use option (1) — the static const — every time.

Convert dd-mm-yyyy string to date

You could use a Regexp.

var result = /^(\d{2})-(\d{2})-(\d{4})$/.exec($("#datepicker").val());
if (result) {
    from = new Date(
        parseInt(result[3], 10), 
        parseInt(result[2], 10) - 1, 
        parseInt(result[1], 10)

How to include !important in jquery

Apparently it's possible to do this in jQuery:

$("#tabs").css("cssText", "height: 650px !important;");


Array initialization in Perl

If I understand you, perhaps you don't need an array of zeroes; rather, you need a hash. The hash keys will be the values in the other array and the hash values will be the number of times the value exists in the other array:

use strict;
use warnings;

my @other_array = (0,0,0,1,2,2,3,3,3,4);
my %tallies;
$tallies{$_} ++ for @other_array;

print "$_ => $tallies{$_}\n" for sort {$a <=> $b} keys %tallies;    


0 => 3
1 => 1
2 => 2
3 => 3
4 => 1

To answer your specific question more directly, to create an array populated with a bunch of zeroes, you can use the technique in these two examples:

my @zeroes = (0) x 5;            # (0,0,0,0,0)

my @zeroes = (0) x @other_array; # A zero for each item in @other_array.
                                 # This works because in scalar context
                                 # an array evaluates to its size.