Programs & Examples On #Versions


SVN (Subversion) Problem "File is scheduled for addition, but is missing" - Using Versions

If you’re using TortoiseSVN…

From your commit window in the “Changes Made” section you can select all the offending files, then right-click and select delete. Finish the commit and the files will be removed from the scheduled additions.

How to hide Bootstrap modal with javascript?

document.getElementById('closeButton').click(); // add a data-dismiss="modal" attribute to an element in the modal and give it this id

Integer ASCII value to character in BASH using printf

One option is to directly input the character you're interested in using hex or octal notation:

printf "\x41\n"
printf "\101\n"

Why is quicksort better than mergesort?

While they're both in the same complexity class, that doesn't mean they both have the same runtime. Quicksort is usually faster than mergesort, just because it's easier to code a tight implementation and the operations it does can go faster. It's because that quicksort is generally faster that people use it instead of mergesort.

However! I personally often will use mergesort or a quicksort variant that degrades to mergesort when quicksort does poorly. Remember. Quicksort is only O(n log n) on average. It's worst case is O(n^2)! Mergesort is always O(n log n). In cases where realtime performance or responsiveness is a must and your input data could be coming from a malicious source, you should not use plain quicksort.

How can I get column names from a table in Oracle?

That information is stored in the ALL_TAB_COLUMNS system table:

SQL> select column_name from all_tab_columns where table_name = 'DUAL';


Or you could DESCRIBE the table if you are using SQL*PLUS:

SQL> desc dual
Name                               Null?    Type
----------------------------------------------------- -------- ---------------------- -------------
DUMMY                               VARCHAR2(1)

changing color of h2

Try CSS:

<h2 style="color:#069">Process Report</h2>

If you have more than one h2 tags which should have the same color add a style tag to the head tag like this:

<style type="text/css">
h2 {

How to remove "disabled" attribute using jQuery?

Always use the prop() method to enable or disable elements when using jQuery (see below for why).

In your case, it would be:

   $('.inputDisabled').prop("disabled", false); // Element(s) are now enabled.

jsFiddle example here.

Why use prop() when you could use attr()/removeAttr() to do this?

Basically, prop() should be used when getting or setting properties (such as autoplay, checked, disabled and required amongst others).

By using removeAttr(), you are completely removing the disabled attribute itself - while prop() is merely setting the property's underlying boolean value to false.

While what you want to do can be done using attr()/removeAttr(), it doesn't mean it should be done (and can cause strange/problematic behaviour, as in this case).

The following extracts (taken from the jQuery documentation for prop()) explain these points in greater detail:

"The difference between attributes and properties can be important in specific situations. Before jQuery 1.6, the .attr() method sometimes took property values into account when retrieving some attributes, which could cause inconsistent behavior. As of jQuery 1.6, the .prop() method provides a way to explicitly retrieve property values, while .attr() retrieves attributes."

"Properties generally affect the dynamic state of a DOM element without changing the serialized HTML attribute. Examples include the value property of input elements, the disabled property of inputs and buttons, or the checked property of a checkbox. The .prop() method should be used to set disabled and checked instead of the .attr() method. The .val() method should be used for getting and setting value."

JavaScript backslash (\) in variables is causing an error

The backslash (\) is an escape character in Javascript (along with a lot of other C-like languages). This means that when Javascript encounters a backslash, it tries to escape the following character. For instance, \n is a newline character (rather than a backslash followed by the letter n).

In order to output a literal backslash, you need to escape it. That means \\ will output a single backslash (and \\\\ will output two, and so on). The reason "aa ///\" doesn't work is because the backslash escapes the " (which will print a literal quote), and thus your string is not properly terminated. Similarly, "aa ///\\\" won't work, because the last backslash again escapes the quote.

Just remember, for each backslash you want to output, you need to give Javascript two.

PHP, Get tomorrows date from date

 * get tomorrow's date in the format requested, default to Y-m-d for MySQL (e.g. 2013-01-04)
 * @param string
 * @return string
public static function getTomorrowsDate($format = 'Y-m-d')
    $date = new DateTime();

    return $date->format($format);

How to to send mail using gmail in Laravel?

Using a G Suite account

If you are using a G Suite account, anything you try will fail. At least at the time, this answer is being typed. You must use account, anything else like will not work.

After you use the address. You just need to update .env as most of the people already mentioned.


Don't forget to create an App password, if you don't see the option probably your 2-factor authentication is not enabled. And there is no need to allow less secure apps if you follow this approach.

How can I render Partial views in mvc 3?

Create your partial view something like:

@model YourModelType
  <!-- HTML to render your object -->

Then in your view use:

@Html.Partial("YourPartialViewName", Model)

If you do not want a strongly typed partial view remove the @model YourModelType from the top of the partial view and it will default to a dynamic type.


The default view engine will search for partial views in the same folder as the view calling the partial and then in the ~/Views/Shared folder. If your partial is located in a different folder then you need to use the full path. Note the use of ~/ in the path below.

@Html.Partial("~/Views/Partials/SeachResult.cshtml", Model)


In short, git is trying to access a repo it considers on another filesystem and to tell it explicitly that you're okay with this, you must set the environment variable GIT_DISCOVERY_ACROSS_FILESYSTEM=1

I'm working in a CI/CD environment and using a dockerized git so I have to set it in that environment docker run -e GIT_DISCOVERY_ACROSS_FILESYSTEM=1 -v $(pwd):/git --rm alpine/git rev-parse --short HEAD\'

If you're curious: Above mounts $(pwd) into the git docker container and passes "rev-parse --short HEAD" to the git command in the container, which it then runs against that mounted volums.

SMTP connect() failed PHPmailer - PHP


use PHPMailer\PHPMailer\PHPMailer;

require_once "PHPMailer/src/Exception.php";
require_once "PHPMailer/src/PHPMailer.php";
require_once "PHPMailer/src/SMTP.php";

$mail = new PHPMailer();

$mail ->isSMTP();
$mail ->Host ="";
$mail -> SMTPAuth = true;
$mail ->Username = '[email protected]';
$mail ->Password = 'password';
$mail ->Port = '587';
$mail ->SMTPSecure ='tls';
$mail ->isHTML(true);

$mail ->setFrom('[email protected]','email send name');

$mail ->addAddress('[email protected]');
$mail ->Subject = 'HelloWorld';
$mail ->Body = 'a test email';

$mail->SMTPOptions = array(
    'ssl' => array(
        'verify_peer' => false,
        'verify_peer_name' => false,
        'allow_self_signed' => true

if ($mail->send()){
    echo "Message has been sent successfully";
    echo "Mailer Error: " . $mail->ErrorInfo;


make sure that you configure less secure app settings in gmail using this link and make sure you downloaded from github

working fine with MAMP server locally :)

How to efficiently concatenate strings in go

My original suggestion was

s12 := fmt.Sprint(s1,s2)

But above answer using bytes.Buffer - WriteString() is the most efficient way.

My initial suggestion uses reflection and a type switch. See (p *pp) doPrint and (p *pp) printArg
There is no universal Stringer() interface for basic types, as I had naively thought.

At least though, Sprint() internally uses a bytes.Buffer. Thus

`s12 := fmt.Sprint(s1,s2,s3,s4,...,s1000)`

is acceptable in terms of memory allocations.

=> Sprint() concatenation can be used for quick debug output.
=> Otherwise use bytes.Buffer ... WriteString

How to use android emulator for testing bluetooth application?

Download Androidx86 from this This is an iso file, so you'd
need something like VMWare or VirtualBox to run it When creating the virtual machine, you need to set the type of guest OS as Linux instead of Other.

After creating the virtual machine set the network adapter to 'Bridged'. · Start the VM and select 'Live CD VESA' at boot.

Now you need to find out the IP of this VM. Go to terminal in VM (use Alt+F1 & Alt+F7 to toggle) and use the netcfg command to find this.

Now you need open a command prompt and go to your android install folder (on host). This is usually C:\Program Files\Android\android-sdk\platform-tools>.

Type adb connect IP_ADDRESS. There done! Now you need to add Bluetooth. Plug in your USB Bluetooth dongle/Bluetooth device.

In VirtualBox screen, go to Devices>USB devices. Select your dongle.

Done! now your Android VM has Bluetooth. Try powering on Bluetooth and discovering/paring with other devices.

Now all that remains is to go to Eclipse and run your program. The Android AVD manager should show the VM as a device on the list.

Alternatively, Under settings of the virtual machine, Goto serialports -> Port 1 check Enable serial port select a port number then select port mode as disconnected click ok. now, start virtual machine. Under Devices -> USB Devices -> you can find your laptop bluetooth listed. You can simply check the option and start testing the android bluetooth application .


Disabling of EditText in Android

This works for me:


Insert a string at a specific index

Just make the following function:

function insert(str, index, value) {
    return str.substr(0, index) + value + str.substr(index);

and then use it like that:

alert(insert("foo baz", 4, "bar "));

Output: foo bar baz

It behaves exactly, like the C# (Sharp) String.Insert(int startIndex, string value).

NOTE: This insert function inserts the string value (third parameter) before the specified integer index (second parameter) in the string str (first parameter), and then returns the new string without changing str!

Change Timezone in Lumen or Laravel 5

You just have to edit de app.php file in config directory Just find next lines

| Application Timezone
| Here you may specify the default timezone for your application, which
| will be used by the PHP date and date-time functions. We have gone
| ahead and set this to a sensible default for you out of the box.

'timezone' => 'UTC',

And.. chage it for:

'timezone' => 'Europe/Paris',

tslint / codelyzer / ng lint error: "for (... in ...) statements must be filtered with an if statement"

A neater way of applying @Helzgate's reply is possibly to replace your 'for .. in' with

for (const field of Object.keys(this.formErrors)) {

Copy / Put text on the clipboard with FireFox, Safari and Chrome

If you support flash you can use and use the flashvars text to set the text

Thats the one i use to copy and you can set as extra if doesn't support these options you can use :

For Internet Explorer: window.clipboardData.setData(DataFormat, Text) and window.clipboardData.getData(DataFormat)

You can use the DataFormat's Text and Url to getData and setData.

And to delete data:

You can use the DataFormat's File, HTML, Image, Text and URL. PS: You Need To Use window.clipboardData.clearData(DataFormat);

And for other thats not support window.clipboardData and swf flash files you can also use control + c button on your keyboard for windows and for mac its command + c

AngularJS : How do I switch views from a controller function?

I've got an example working.

Here's how my doc looks:

    <link rel="stylesheet" href="css/main.css">
    <script src="//"></script>
    <script src=""></script>
    <script src=""></script>
    <script src="js/app.js"></script>
    <script src="controllers/ctrls.js"></script>
<body ng-app="app">
    <div id="contnr">

Here's what my partial looks like:

<div id="welcome" ng-controller="Index">
    <b>Welcome! Please Login!</b>
    <form ng-submit="auth()">
        <input class="input login username" type="text" placeholder="username" /><br>
        <input class="input login password" type="password" placeholder="password" /><br>
        <input class="input login submit" type="submit" placeholder="login!" />

Here's what my Ctrl looks like:

app.controller('Index', function($scope, $routeParams, $location){
    $scope.auth = function(){

app is my module:

var app = angular.module('app', ['ngResource']).config(function($routeProvider)...

Hope this is helpful!

escaping question mark in regex javascript

Whenever you have a known pattern (i.e. you do not use a variable to build a RegExp), use literal regex notation where you only need to use single backslashes to escape special regex metacharacters:

var re = /I like your Apartment\. Could we schedule a viewing\?/g;
                               ^^                            ^^

Whenever you need to build a RegExp dynamically, use RegExp constructor notation where you MUST double backslashes for them to denote a literal backslash:

var questionmark_block = "\\?"; // A literal ?
var initial_subpattern = "I like your Apartment\\. Could we schedule a viewing"; // Note the dot must also be escaped to match a literal dot
var re = new RegExp(initial_subpattern + questionmark_block, "g");

And if you use the String.raw string literal you may use \ as is (see an example of using a template string literal where you may put variables into the regex pattern):

const questionmark_block = String.raw`\?`; // A literal ?
const initial_subpattern = "I like your Apartment\\. Could we schedule a viewing";
const re = new RegExp(`${initial_subpattern}${questionmark_block}`, 'g'); // Building pattern from two variables
console.log(re); // => /I like your Apartment\. Could we schedule a viewing\?/g

A must-read: RegExp: Description at MDN.

splitting a string into an array in C++ without using vector

#define MAXSPACE 25

string line =  "test one two three.";
string arr[MAXSPACE];
string search = " ";
int spacePos;
int currPos = 0;
int k = 0;
int prevPos = 0;


    spacePos = line.find(search,currPos);

    if(spacePos >= 0)

        currPos = spacePos;
        arr[k] = line.substr(prevPos, currPos - prevPos);
        prevPos = currPos;

}while( spacePos >= 0);

arr[k] = line.substr(prevPos,line.length());

for(int i = 0; i < k; i++)
   cout << arr[i] << endl;

Setting Remote Webdriver to run tests in a remote computer using Java

By Default the InternetExplorerDriver listens on port "5555". Change your huburl to match that. you can look on the cmd box window to confirm.

Java List.contains(Object with field value equal to x)

Collection.contains() is implemented by calling equals() on each object until one returns true.

So one way to implement this is to override equals() but of course, you can only have one equals.

Frameworks like Guava therefore use predicates for this. With Iterables.find(list, predicate), you can search for arbitrary fields by putting the test into the predicate.

Other languages built on top of the VM have this built in. In Groovy, for example, you simply write:

def result = list.find{ == 'John' }

Java 8 made all our lives easier, too:

List<Foo> result =
    .filter(it -> "John".equals(it.getName())

If you care about things like this, I suggest the book "Beyond Java". It contains many examples for the numerous shortcomings of Java and how other languages do better.

How to set opacity to the background color of a div?

I would say that the easiest way is to use transparent background image.

background: url("") repeat top left;

How to avoid reverse engineering of an APK file?

If your app is this sensitive then you should consider the payment processing part at server side. Try to change your payment processing algorithms. Use android app only for collecting and displaying user information (i.e account balance) and rather than processing payments within java codes, send this task to your server using a secure SSL protocol with encrypted parameters. Create fully encrypted and secure API to communicate with your server.

Of course, It can also be hacked too and it has nothing to do with source codes protection but consider it another security layer to make it harder for hackers to trick your app.

how to access iFrame parent page using jquery?

how to access iFrame parent page using jquery


jQuery is a library on top of JavaScript, not a complete replacement for it. You don't have to replace every last JavaScript expression with something involving $.

Boolean operators ( &&, -a, ||, -o ) in Bash

Rule of thumb: Use -a and -o inside square brackets, && and || outside.

It's important to understand the difference between shell syntax and the syntax of the [ command.

  • && and || are shell operators. They are used to combine the results of two commands. Because they are shell syntax, they have special syntactical significance and cannot be used as arguments to commands.

  • [ is not special syntax. It's actually a command with the name [, also known as test. Since [ is just a regular command, it uses -a and -o for its and and or operators. It can't use && and || because those are shell syntax that commands don't get to see.

But wait! Bash has a fancier test syntax in the form of [[ ]]. If you use double square brackets, you get access to things like regexes and wildcards. You can also use shell operators like &&, ||, <, and > freely inside the brackets because, unlike [, the double bracketed form is special shell syntax. Bash parses [[ itself so you can write things like [[ $foo == 5 && $bar == 6 ]].

What is the best way to remove accents (normalize) in a Python unicode string?


import unicodedata
from random import choice

import perfplot
import regex
import text_unidecode

def remove_accent_chars_regex(x: str):
    return regex.sub(r'\p{Mn}', '', unicodedata.normalize('NFKD', x))

def remove_accent_chars_join(x: str):
    # answer by MiniQuark
    return u"".join([c for c in unicodedata.normalize('NFKD', x) if not unicodedata.combining(c)])
    setup=lambda n: ''.join([choice('Málaga François Phút Hon ??') for i in range(n)]),
    labels=['regex', 'join', 'unidecode'],
    n_range=[2 ** k for k in range(22)],
    equality_check=None, relative_to=0, xlabel='str len'

How to change the data type of a column without dropping the column with query?

ALTER tablename MODIFY columnName newColumnType

I'm not sure how it will handle the change from datetime to varchar though, so you may need to rename the column, add a new one with the old name and the correct data type (varchar) and then write an update query to populate the new column from the old.

How to push to History in React Router v4?

Be careful that don't use [email protected] or [email protected] with [email protected]. URL will update after history.push or any other push to history instructions but navigation is not working with react-router. use npm install [email protected] to change the history version. see React router not working after upgrading to v 5.

I think this problem is happening when push to history happened. for example using <NavLink to="/apps"> facing a problem in NavLink.js that consume <RouterContext.Consumer>. context.location is changing to an object with action and location properties when the push to history occurs. So currentLocation.pathname is null to match the path.

How to change screen resolution of Raspberry Pi

After uncommenting disable_overscan=1 follow my lead. In the link, when you search for Video options, you'll also get hdmi_group and hdmi_mode. For, hdmi_group choose 1 if you're using you TV as an video output or choose 2 for monitors. Then in hdmi_mode, you can select the resolution you want from the list. I chose :- hdmi_group=2 hdmi_mode=23 And it worked.enter image description here

Get the current displaying UIViewController on the screen in AppDelegate.m

zirinisp's Answer in Swift:

extension UIWindow {

    func visibleViewController() -> UIViewController? {
        if let rootViewController: UIViewController  = self.rootViewController {
            return UIWindow.getVisibleViewControllerFrom(rootViewController)
        return nil

    class func getVisibleViewControllerFrom(vc:UIViewController) -> UIViewController {

        if vc.isKindOfClass(UINavigationController.self) {

            let navigationController = vc as UINavigationController
            return UIWindow.getVisibleViewControllerFrom( navigationController.visibleViewController)

        } else if vc.isKindOfClass(UITabBarController.self) {

            let tabBarController = vc as UITabBarController
            return UIWindow.getVisibleViewControllerFrom(tabBarController.selectedViewController!)

        } else {

            if let presentedViewController = vc.presentedViewController {

                return UIWindow.getVisibleViewControllerFrom(presentedViewController.presentedViewController!)

            } else {

                return vc;


 if let topController = window.visibleViewController() {

How to navigate through textfields (Next / Done Buttons)

 -(BOOL)textFieldShouldReturn:(UITextField *)textField
   [[self.view viewWithTag:textField.tag+1] becomeFirstResponder];
   return YES;

How does the "position: sticky;" property work?

two answer here:

  1. remove overflow property from body tag

  2. set height: 100% to the body to fix the problem with overflow-y: auto

min-height: 100% not-working instead of height: 100%

ASP.NET Custom Validator Client side & Server Side validation not firing

Your CustomValidator will only fire when the TextBox isn't empty.

If you need to ensure that it's not empty then you'll need a RequiredFieldValidator too.

Note: If the input control is empty, no validation functions are called and validation succeeds. Use a RequiredFieldValidator control to require the user to enter data in the input control.


If your CustomValidator specifies the ControlToValidate attribute (and your original example does) then your validation functions will only be called when the control isn't empty.

If you don't specify ControlToValidate then your validation functions will be called every time.

This opens up a second possible solution to the problem. Rather than using a separate RequiredFieldValidator, you could omit the ControlToValidate attribute from the CustomValidator and setup your validation functions to do something like this:

Client Side code (Javascript):

function TextBoxDCountyClient(sender, args) {
    var v = document.getElementById('<%=TextBoxDTownCity.ClientID%>').value;
    if (v == '') {
        args.IsValid = false;  // field is empty
    else {
        // do your other validation tests here...

Server side code (C#):

protected void TextBoxDTownCity_Validate(
    object source, ServerValidateEventArgs args)
    string v = TextBoxDTownCity.Text;
    if (v == string.Empty)
        args.IsValid = false;  // field is empty
        // do your other validation tests here...

How to remove specific substrings from a set of strings in Python?

All you need is a bit of black magic!

>>> a = ["cherry.bad","pear.good", "apple.good"]
>>> a = list(map(lambda x: x.replace('.good','').replace('.bad',''),a))
>>> a
['cherry', 'pear', 'apple']


A few days ago I've had an issue with triggers, and I've figured out that ON UPDATE CASCADE can be useful. Take a look at this example (PostgreSQL):

    name TEXT UNIQUE

    name TEXT UNIQUE

    club_name TEXT REFERENCES club(name) ON UPDATE CASCADE,
    band_name TEXT REFERENCES band(name) ON UPDATE CASCADE,
    concert_date DATE

In my issue, I had to define some additional operations (trigger) for updating the concert's table. Those operations had to modify club_name and band_name. I was unable to do it, because of reference. I couldn't modify concert and then deal with club and band tables. I couldn't also do it the other way. ON UPDATE CASCADE was the key to solve the problem.

How to set a fixed width column with CSS flexbox

You should use the flex or flex-basis property rather than width. Read more on MDN.

.flexbox .red {
  flex: 0 0 25em;

The flex CSS property is a shorthand property specifying the ability of a flex item to alter its dimensions to fill available space. It contains:

flex-grow: 0;     /* do not grow   - initial value: 0 */
flex-shrink: 0;   /* do not shrink - initial value: 1 */
flex-basis: 25em; /* width/height  - initial value: auto */

A simple demo shows how to set the first column to 50px fixed width.

.flexbox {_x000D_
  display: flex;_x000D_
.red {_x000D_
  background: red;_x000D_
  flex: 0 0 50px;_x000D_
.green {_x000D_
  background: green;_x000D_
  flex: 1;_x000D_
.blue {_x000D_
  background: blue;_x000D_
  flex: 1;_x000D_
<div class="flexbox">_x000D_
  <div class="red">1</div>_x000D_
  <div class="green">2</div>_x000D_
  <div class="blue">3</div>_x000D_

See the updated codepen based on your code.

Vertically align text next to an image?

You probably want this:

   <img style="width:30px; height:30px;">
   <span style="vertical-align:50%; line-height:30px;">Didn't work.</span>

As others have suggested, try vertical-align on the image:

   <img style="width:30px; height:30px; vertical-align:middle;">
   <span>Didn't work.</span>

CSS isn't annoying. You just don't read the documentation. ;P

What is the best way to convert seconds into (Hour:Minutes:Seconds:Milliseconds) time?

I'd suggest you use the TimeSpan class for this.

public static void Main(string[] args)
    TimeSpan t = TimeSpan.FromSeconds(80);

    t = TimeSpan.FromSeconds(868693412);



Display open transactions in MySQL

Although there won't be any remaining transaction in the case, as @Johan said, you can see the current transaction list in InnoDB with the query below if you want.

SELECT * FROM information_schema.innodb_trx\G

From the document:

The INNODB_TRX table contains information about every transaction (excluding read-only transactions) currently executing inside InnoDB, including whether the transaction is waiting for a lock, when the transaction started, and the SQL statement the transaction is executing, if any.

remove empty lines from text file with PowerShell

(Get-Content c:\FileWithEmptyLines.txt) | 
    Foreach { $_ -Replace  "Old content", " New content" } | 
    Set-Content c:\FileWithEmptyLines.txt;

How can I make one python file run another?

There are more than a few ways. I'll list them in order of inverted preference (i.e., best first, worst last):

  1. Treat it like a module: import file. This is good because it's secure, fast, and maintainable. Code gets reused as it's supposed to be done. Most Python libraries run using multiple methods stretched over lots of files. Highly recommended. Note that if your file is called, your import should not include the .py extension at the end.
  2. The infamous (and unsafe) exec command: Insecure, hacky, usually the wrong answer. Avoid where possible.
    • execfile('') in Python 2
    • exec(open('').read()) in Python 3
  3. Spawn a shell process: os.system('python'). Use when desperate.

My Application Could not open ServletContext resource

The file name u used spring-dispatcher-servlet.xml
kindly check in web.xml
servlet name as spring-dispatcher at both tag  <servlet> and <servlet-mapping>
in your case it should be


Encrypt and Decrypt text with RSA in PHP

Security warning: This code snippet is vulnerable to Bleichenbacher's 1998 padding oracle attack. See this answer for better security.

class MyEncryption

    public $pubkey = '...public key here...';
    public $privkey = '...private key here...';

    public function encrypt($data)
        if (openssl_public_encrypt($data, $encrypted, $this->pubkey))
            $data = base64_encode($encrypted);
            throw new Exception('Unable to encrypt data. Perhaps it is bigger than the key size?');

        return $data;

    public function decrypt($data)
        if (openssl_private_decrypt(base64_decode($data), $decrypted, $this->privkey))
            $data = $decrypted;
            $data = '';

        return $data;

What is the difference between <%, <%=, <%# and -%> in ERB in Rails?

Rails does not use the stdlib's ERB by default, it uses erubis. Sources: this dev's comment, ActionView's gemspec, accepted merge request I did while writing this.

There are behavior differences between them, in particular on how the hyphen operators %- and -% work.

Documentation is scarce, Where is Ruby's ERB format "officially" defined? so what follows are empirical conclusions.

All tests suppose:

require 'erb'
require 'erubis'

When you can use -

  • ERB: you must pass - to trim_mode option of to use it.
  • erubis: enabled by default.


begin"<%= 'a' -%>\nb").result; rescue SyntaxError ; else raise; end"<%= 'a' -%>\nb"  , nil, '-') .result == 'ab'  or raise"<%= 'a' -%>  \n b").result == 'a b' or raise

What -% does:

  • ERB: remove the next character if it is a newline.

  • erubis:

    • in <% %> (without =), - is useless because <% %> and <% -%> are the same. <% %> removes the current line if it only contains whitespaces, and does nothing otherwise.

    • in <%= -%> (with =):

      • remove the entire line if it only contains whitespaces
      • else, if there is a non-space before the tag, and only whitesapces after, remove the whitespces that come after
      • else, there is a non-space after the tag: do nothing


# Remove"a \nb <% 0 -%>\n c", nil, '-').result == "a \nb  c" or raise

# Don't do anything: not followed by newline, but by space:"a\n<% 0 -%> \nc", nil, '-').result == "a\nb \nc" or raise

# Remove the current line because only whitesapaces:" <% 0 %> \nb").result == 'b' or raise

# Same as above, thus useless because longer." <% 0 -%> \nb").result == 'b' or raise

# Don't do anything because line not empty."a <% 0 %> \nb").result == "a  \nb" or raise" <% 0 %> a\nb").result == "  a\nb" or raise" <% 0 -%> a\nb").result == "  a\nb" or raise

# Don't remove the current line because of `=`:" <%= 0 %> \nb").result == " 0 \nb" or raise

# Remove the current line even with `=`:" <%= 0 -%> \nb").result == " 0b"   or raise

# Remove forward only because of `-` and non space before:"a <%= 0 -%> \nb").result == "a 0b"   or raise

# Don't do anything because non-whitespace forward:" <%= 0 -%> a\nb").result == " 0 a\nb"   or raise

What %- does:

  • ERB: remove whitespaces before tag and after previous newlines, but only if there are only whitespaces before.

  • erubis: useless because <%- %> is the same as <% %> (without =), and this cannot be used with = which is the only case where -% can be useful. So never use this.


# Remove"a \n  <%- 0 %> b\n c", nil, '-').result == "a \n b\n c" or raise

# b is not whitespace: do nothing:"a \nb  <%- 0 %> c\n d", nil, '-').result == "a \nb   c\n d" or raise

What %- and -% do together

The exact combination of both effects separately.

How to turn off caching on Firefox?

You can use CTRL-F5 to reload bypassing the cache.

You can set the preferences in firefox not to use the cache

network.http.use-cache = false

You can setup you web server to send a no-cache/Expires/Cache-Control headers for the js files.

Here is an example for apache web server.

shuffling/permutating a DataFrame in pandas

This might be more useful when you want your index shuffled.

def shuffle(df):
    index = list(df.index)
    df = df.ix[index]
    return df

It selects new df using new index, then reset them.

Python - How do you run a .py file?

Your command should include the url parameter as stated in the script usage comments. The main function has 2 parameters, url and out (which is set to a default value) C:\python23\python "C:\PathToYourScript\" "C:\OptionalOutput\"

How does cellForRowAtIndexPath work?

1) The function returns a cell for a table view yes? So, the returned object is of type UITableViewCell. These are the objects that you see in the table's rows. This function basically returns a cell, for a table view. But you might ask, how the function would know what cell to return for what row, which is answered in the 2nd question

2)NSIndexPath is essentially two things-

  • Your Section
  • Your row

Because your table might be divided to many sections and each with its own rows, this NSIndexPath will help you identify precisely which section and which row. They are both integers. If you're a beginner, I would say try with just one section.

It is called if you implement the UITableViewDataSource protocol in your view controller. A simpler way would be to add a UITableViewController class. I strongly recommend this because it Apple has some code written for you to easily implement the functions that can describe a table. Anyway, if you choose to implement this protocol yourself, you need to create a UITableViewCell object and return it for whatever row. Have a look at its class reference to understand re-usablity because the cells that are displayed in the table view are reused again and again(this is a very efficient design btw).

As for when you have two table views, look at the method. The table view is passed to it, so you should not have a problem with respect to that.

How to get the GL library/headers?

Some of the answers above, in regards to linux, are either incomplete, or flat out wrong.

For example, /usr/include/GL/gl.h is not part of mesa-common-dev or has not been for many years.

At any rate, for a more current answer, these two packages are important:

The glu.h is part of glu itself:


Mesa is evidently significantly larger. Its headers are a bit variable, I suppose, depending on the flags given to meson, but should include these typically:


Hope that helps anyone finding an answer this question in the future; compiling dosbox needs this, for instance, due to SDL opengl.

How to check whether a string is Base64 encoded or not

Well you can:

  • Check that the length is a multiple of 4 characters
  • Check that every character is in the set A-Z, a-z, 0-9, +, / except for padding at the end which is 0, 1 or 2 '=' characters

If you're expecting that it will be base64, then you can probably just use whatever library is available on your platform to try to decode it to a byte array, throwing an exception if it's not valid base 64. That depends on your platform, of course.

Add error bars to show standard deviation on a plot in R

You can use arrows:

arrows(x,y-sd,x,y+sd, code=3, length=0.02, angle = 90)

Use multiple @font-face rules in CSS

Note, you may also be interested in:

Custom web font not working in IE9

Which includes a more descriptive breakdown of the CSS you see below (and explains the tweaks that make it work better on IE6-9).

@font-face {
  font-family: 'Bumble Bee';
  src: url('bumblebee-webfont.eot');
  src: local('?'), 
       url('bumblebee-webfont.woff') format('woff'), 
       url('bumblebee-webfont.ttf') format('truetype'), 
       url('bumblebee-webfont.svg#webfontg8dbVmxj') format('svg');

@font-face {
  font-family: 'GestaReFogular';
  src: url('gestareg-webfont.eot');
  src: local('?'), 
       url('gestareg-webfont.woff') format('woff'), 
       url('gestareg-webfont.ttf') format('truetype'), 
       url('gestareg-webfont.svg#webfontg8dbVmxj') format('svg');

body {
  background: #fff url(../images/body-bg-corporate.gif) repeat-x;
  padding-bottom: 10px;
  font-family: 'GestaRegular', Arial, Helvetica, sans-serif;

h1 {
  font-family: "Bumble Bee", "Times New Roman", Georgia, Serif;

And your follow-up questions:

Q. I would like to use a font such as "Bumble bee," for example. How can I use @font-face to make that font available on the user's computer?

Note that I don't know what the name of your Bumble Bee font or file is, so adjust accordingly, and that the font-face declaration should precede (come before) your use of it, as I've shown above.

Q. Can I still use the other @font-face typeface "GestaRegular" as well? Can I use both in the same stylesheet?

Just list them together as I've shown in my example. There is no reason you can't declare both. All that @font-face does is instruct the browser to download and make a font-family available. See:

Combination of async function + await + setTimeout

await setTimeout(()=>{}, 200);

Will work if your Node version is 15 and above.

Get most recent row for given ID

I had a similar problem. I needed to get the last version of page content translation, in other words - to get that specific record which has highest number in version column. So I select all records ordered by version and then take the first row from result (by using LIMIT clause).

FROM `page_contents_translations`

Fatal error: Call to undefined function mb_strlen()

On Centos, RedHat, Fedora and other yum-my systems it is much simpler than the PHP manual suggests:

yum install php-mbstring
service httpd restart

How do I remove my IntelliJ license in 2019.3?

Not sure about older versions, but in 2016.2 removing the .key file(s) didn't work for me.

I'm using my JetBrains account and used the 'Remove License' button found at the bottom of the registration dialog. You can find this under the Help menu or from the startup dialog via Configure -> Manage License....

How to use the 'main' parameter in package.json?

To answer your first question, the way you load a module is depending on the module entry point and the main parameter of the package.json.

Let's say you have the following file structure:

|-- lib
|   |-- module.js
|-- package.json

Without main parameter in the package.json, you have to load the module by giving the module entry point: require('my-npm-module/lib/module.js').

If you set the package.json main parameter as follows "main": "lib/module.js", you will be able to load the module this way: require('my-npm-module').

Do we need type="text/css" for <link> in HTML5

For LINK elements the content-type is determined in the HTTP-response so the type attribute is superfluous. This is OK for all browsers.

CXF: No message body writer found for class - automatically mapping non-simple resources

It isn't quite out of the box but CXF does support JSON bindings to rest services. See cxf jax-rs json docs here. You'll still need to do some minimal configuration to have the provider available and you need to be familiar with jettison if you want to have more control over how the JSON is formed.

EDIT: Per comment request, here is some code. I don't have a lot of experience with this but the following code worked as an example in a quick test system.

//TestApi parts
@Path ( "test" )
@Produces ( "application/json" )
public Demo getDemo () {
    Demo d = new Demo (); = 1; = "test";
    return d;

//client config for a TestApi interface
List providers = new ArrayList ();
JSONProvider jsonProvider = new JSONProvider ();
Map<String, String> map = new HashMap<String, String> ();
map.put ( "", "myapi" );
jsonProvider.setNamespaceMap ( map );
providers.add ( jsonProvider );
TestApi proxy = JAXRSClientFactory.create ( url, TestApi.class, 
    providers, true );

Demo d = proxy.getDemo ();
if ( d != null ) {
    System.out.println ( + ":" + );

//the Demo class
@XmlRootElement ( name = "demo", namespace = "" )
@XmlType ( name = "demo", namespace = "", 
    propOrder = { "name", "id" } )
@XmlAccessorType ( XmlAccessType.FIELD )
public class Demo {

    public String name;
    public int id;


  1. The providers list is where you code configure the JSON provider on the client. In particular, you see the namespace mapping. This needs to match what is on your server side configuration. I don't know much about Jettison options so I'm not much help on manipulating all of the various knobs for controlling the marshalling process.
  2. Jettison in CXF works by marshalling XML from a JAXB provider into JSON. So you have to ensure that the payload objects are all marked up (or otherwise configured) to marshall as application/xml before you can have them marshall as JSON. If you know of a way around this (other than writing your own message body writer), I'd love to hear about it.
  3. I use spring on the server so my configuration there is all xml stuff. Essentially, you need to go through the same process to add the JSONProvider to the service with the same namespace configuration. Don't have code for that handy but I imagine it will mirror the client side fairly well.

This is a bit dirty as an example but will hopefully get you going.

Edit2: An example of a message body writer that is based on xstream to avoid jaxb.

@Produces ( "application/json" )
@Consumes ( "application/json" )
public class XstreamJsonProvider implements MessageBodyReader<Object>,
    MessageBodyWriter<Object> {

public boolean isWriteable ( Class<?> type, Type genericType, 
    Annotation[] annotations, MediaType mediaType ) {
    return MediaType.APPLICATION_JSON_TYPE.equals ( mediaType ) 
        && type.equals ( Demo.class );

public long getSize ( Object t, Class<?> type, Type genericType, 
    Annotation[] annotations, MediaType mediaType ) {
    // I'm being lazy - should compute the actual size
    return -1;

public void writeTo ( Object t, Class<?> type, Type genericType, 
    Annotation[] annotations, MediaType mediaType, 
    MultivaluedMap<String, Object> httpHeaders, OutputStream entityStream ) 
    throws IOException, WebApplicationException {
    // deal with thread safe use of xstream, etc.
    XStream xstream = new XStream ( new JettisonMappedXmlDriver () );
    xstream.setMode ( XStream.NO_REFERENCES );
    // add safer encoding, error handling, etc.
    xstream.toXML ( t, entityStream );

public boolean isReadable ( Class<?> type, Type genericType, 
    Annotation[] annotations, MediaType mediaType ) {
    return MediaType.APPLICATION_JSON_TYPE.equals ( mediaType ) 
        && type.equals ( Demo.class );

public Object readFrom ( Class<Object> type, Type genericType, 
    Annotation[] annotations, MediaType mediaType, 
    MultivaluedMap<String, String> httpHeaders, InputStream entityStream ) 
    throws IOException, WebApplicationException {
    // add error handling, etc.
    XStream xstream = new XStream ( new JettisonMappedXmlDriver () );
    return xstream.fromXML ( entityStream );

//now your client just needs this
List providers = new ArrayList ();
XstreamJsonProvider jsonProvider = new XstreamJsonProvider ();
providers.add ( jsonProvider );
TestApi proxy = JAXRSClientFactory.create ( url, TestApi.class, 
    providers, true );

Demo d = proxy.getDemo ();
if ( d != null ) {
    System.out.println ( + ":" + );

The sample code is missing the parts for robust media type support, error handling, thread safety, etc. But, it ought to get you around the jaxb issue with minimal code.

EDIT 3 - sample server side configuration As I said before, my server side is spring configured. Here is a sample configuration that works to wire in the provider:

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns=""

<import resource="classpath:META-INF/cxf/cxf.xml" />

<jaxrs:server id="TestApi">
        <ref bean="testApi" />
        <bean id="xstreamJsonProvider" class="" />

<bean id="testApi" class="">


I have also noted that in the latest rev of cxf that I'm using there is a difference in the media types, so the example above on the xstream message body reader/writer needs a quick modification where isWritable/isReadable change to:

return MediaType.APPLICATION_JSON_TYPE.getType ().equals ( mediaType.getType () )
    && MediaType.APPLICATION_JSON_TYPE.getSubtype ().equals ( mediaType.getSubtype () )
    && type.equals ( Demo.class );

EDIT 4 - non-spring configuration Using your servlet container of choice, configure


with at least 2 init params of:


where the serviceClasses is a space separated list of the service implementations you want bound, such as the TestApi mentioned above and the providers is a space separated list of message body providers, such as the XstreamJsonProvider mentioned above. In tomcat you might add the following to web.xml:


That is pretty much the quickest way to run it without spring. If you are not using a servlet container, you would need to configure the JAXRSServerFactoryBean.setProviders with an instance of XstreamJsonProvider and set the service implementation via the JAXRSServerFactoryBean.setResourceProvider method. Check the CXFNonSpringJaxrsServlet.init method to see how they do it when setup in a servlet container.

That ought to get you going no matter your scenario.

Mime type for WOFF fonts?

For all Solution index.php remove form url and woff file allowed. for write below code in .htaccess file and and make this alternation to your application/config/config.php file: $config['index_page'] = '';

For only Linux hosting server. .htaccess file details

AddType font/ttf .ttf
AddType font/eot .eot
AddType font/otf .otf
AddType font/woff .woff
<IfModule mod_rewrite.c>
    RewriteEngine On
    RewriteBase /

    #Removes access to the system folder by users.
    #Additionally this will allow you to create a System.php controller,
    #previously this would not have been possible.
    #'system' can be replaced if you have renamed your system folder.
    RewriteCond %{REQUEST_URI} ^system.*
    RewriteRule ^(.*)$ /index.php?/$1 [L]

    #When your application folder isn't in the system folder
    #This snippet prevents user access to the application folder
    #Submitted by: Fabdrol
    #Rename 'application' to your applications folder name.
    RewriteCond %{REQUEST_URI} ^application.*
    RewriteRule ^(.*)$ /index.php?/$1 [L]

    #Checks to see if the user is attempting to access a valid file,
    #such as an image or css document, if this isn't true it sends the
    #request to index.php
    RewriteCond %{REQUEST_FILENAME} !-f
    RewriteCond %{REQUEST_FILENAME} !-d
    RewriteRule ^(.*)$ index.php?/$1 [L]

<IfModule !mod_rewrite.c>
    # If we don't have mod_rewrite installed, all 404's
    # can be sent to index.php, and everything works as normal.
    # Submitted by: ElliotHaughin

    ErrorDocument 404 /index.php

Is there a way to check if a file is in use?

Aside from working 3-liners and just for reference: If you want the full blown information - there is a little project on Microsoft Dev Center:

From the Introduction:

The C# sample code developed in .NET Framework 4.0 would help in finding out which is the process that is having a lock on a file. RmStartSession function which is included in rstrtmgr.dll has been used to create a restart manager session and according to the return result a new instance of Win32Exception object is created. After registering the resources to a Restart Manager session via RmRegisterRescources function, RmGetList function is invoked to check what are the applications are using a particular file by enumerating the RM_PROCESS_INFO array.

It works by connecting to the "Restart Manager Session".

The Restart Manager uses the list of resources registered with the session to determine which applications and services must be shut down and restarted. Resources can be identified by filenames, service short names, or RM_UNIQUE_PROCESS structures that describe running applications.

It might be a little overengineered for your particular needs... But if that is what you want, go ahead and grab the vs-project.

How can I select from list of values in Oracle

Starting from Oracle 12.2, you don't need the TABLE function, you can directly select from the built-in collection.

SQL> select * FROM sys.odcinumberlist(5,2,6,3,78);


SQL> select * FROM sys.odcivarchar2list('A','B','C','D');


How do I programmatically set the value of a select box element using JavaScript?

Not answering the question, but you can also select by index, where i is the index of the item you wish to select:

var formObj = document.getElementById('myForm');
formObj.leaveCode[i].selected = true;

You can also loop through the items to select by display value with a loop:

for (var i = 0, len < formObj.leaveCode.length; i < len; i++) 
    if (formObj.leaveCode[i].value == 'xxx') formObj.leaveCode[i].selected = true;

How to split a string with any whitespace chars as delimiters

String str = "Hello   World";
String res[] = str.split("\\s+");

How do I get an empty array of any size in python?

also you can extend that with extend method of list.

a= []

What is the difference between a process and a thread?

A process is a collection of code, memory, data and other resources. A thread is a sequence of code that is executed within the scope of the process. You can (usually) have multiple threads executing concurrently within the same process.

The OutputPath property is not set for this project

had this problem as output from Azure DevOps after setting to build the .csproj instead of the .sln in the Build Pipeline.

The solution for me: Edit .csproj of the affected project, then copy your whole

<PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCpu' ">

Node, paste it, and then change the first line as followed:

    <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|any cpu' ">

The reason is, that in my case the error said

Please check to make sure that you have specified a valid combination of Configuration and Platform for this project.  Configuration='release'  Platform='any cpu'.  

Why Azure wants to use "any cpu" instead of the default "AnyCpu" is a mystery for me, but this hack works.

Javascript: How to remove the last character from a div or a string?

Are u sure u want to remove only last character. What if the user press backspace from the middle of the word.. Its better to get the value from the field and replace the divs html. On keyup


Commenting code in Notepad++

Without having selected a language type for your file there are no styles defined. Comment and block comment are language specific style preferences. If that's a PITA...

To select for multi-line editing you can use

shift + alt + down arrow

Set initially selected item in Select list in Angular2

If you use

<select [ngModel]="object">
    <option *ngFor="let object of objects" [ngValue]="object">{{}}</option>

You need to set the property object in you components class to the item from objects that you want to have pre-selected.

class MyComponent {
  objects = [{name: 'a'}, {name: 'b'}, {name: 'c'}];
  constructor() {
    this.object = this.objects[1];

Show Current Location and Nearby Places and Route between two places using Google Maps API in Android

You can use google map Obtaining User Location here!

After obtaining your location(longitude and latitude), you can use google place api

This code can help you get your location easily but not the best way.

locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
Criteria criteria = new Criteria();
String bestProvider = locationManager.getBestProvider(criteria, true);
Location location = locationManager.getLastKnownLocation(bestProvider);  

No restricted globals

This is a simple and maybe not the best solution, but it works.

On the line above the line you get your error, paste this:

// eslint-disable-next-line no-restricted-globals

Flutter plugin not installed error;. When running flutter doctor

You missed this step in the installation process.

Install the Flutter and Dart plugins:

  • Start Android Studio.
  • Open plugin preferences (File → Settings → Plugins on Windows & Linux OR Preferences → Plugins on macOS).
  • Select Browse repositories, select the Flutter plugin and click Install.
  • Click Yes when prompted to install the Dart plugin.
  • Click Restart when prompted.

If are using Visual Studio Code, to Install the Flutter and Dart plugins:

  • Start VS Code.
  • Invoke View → Command Palette.
  • Type install, and select Extensions: Install Extensions.
  • Type flutter in the extensions search field, select Flutter in the list, and click Install. This also installs the required Dart plugin.
  • Validate your setup with the Flutter Doctor
  • Invoke View → Command Palette….
  • Type doctor, and select the Flutter: Run Flutter Doctor.

Review the output in the OUTPUT pane for any issues.

Exact difference between CharSequence and String in java


One is an interface (CharSequence) while other is a concrete implementation of that interface (String).

CharSequence animal = "cat"  // `String` object presented as the interface `CharSequence`.

Just like ArrayList is a List, and HashMap is a Map, so too String is a CharSequence.

As an interface, normally the CharSequence would be more commonly seen than String, but some twisted history resulted in the interface being defined years after the implementation. So in older APIs we often see String while in newer APIs we tend to see CharSequence used to define arguments and return types.


Nowadays we know that generally an API/framework should focus on exporting interfaces primarily and concrete classes secondarily. But we did not always know this lesson so well.

The String class came first in Java. Only later did they place a front-facing interface, CharSequence.

Twisted History

A little history might help with understanding.

In its early days, Java was rushed to market a bit ahead of its time, due to the Internet/Web mania animating the industry. Some libraries were not as well thought-through as they should have been. String handling was one of those areas.

Also, Java was one of the earliest production-oriented non-academic Object-Oriented Programming (OOP) environments. The only successful real-world rubber-meets-the-road implementations of OOP before that was some limited versions of SmallTalk, then Objective-C with NeXTSTEP/OpenStep. So, many practical lessons were yet to be learned.

Java started with the String class and StringBuffer class. But those two classes were unrelated, not tied to each other by inheritance nor interface. Later, the Java team recognized that there should have been a unifying tie between string-related implementations to make them interchangeable. In Java 4 the team added the CharSequence interface and retroactively implemented that interface on String and String Buffer, as well as adding another implementation CharBuffer. Later in Java 5 they added StringBuilder, basically a unsynchronized and therefore somewhat faster version of StringBuffer.

So these string-oriented classes are a bit of a mess, and a little confusing to learn about. Many libraries and interfaces were built to take and return String objects. Nowadays such libraries should generally be built to expect CharSequence. But (a) String seems to still dominate the mindspace, and (b) there may be some subtle technical issues when mixing the various CharSequence implementations. With the 20/20 vision of hindsight we can see that all this string stuff could have been better handled, but here we are.

Ideally Java would have started with an interface and/or superclass that would be used in many places where we now use String, just as we use the Collection or List interfaces in place of the ArrayList or LinkedList implementations.

Interface Versus Class

The key difference about CharSequence is that it is an interface, not an implementation. That means you cannot directly instantiate a CharSequence. Rather you instantiate one of the classes that implements that interface.

For example, here we have x that looks like a CharSequence but underneath is actually a StringBuilder object.

CharSequence x = new StringBuilder( "dog" );  // Looks like a `CharSequence` but is actually a `StringBuilder` instance.

This becomes less obvious when using a String literal. Keep in mind that when you see source code with just quote marks around characters, the compiler is translating that into a String object.

CharSequence y = "cat";  // Looks like a `CharSequence` but is actually a `String` instance.

Literal versus constructor

There are some subtle differences between "cat" and new String("cat") as discussed in this other Question, but are irrelevant here.

Class Diagram

This class diagram may help to guide you. I noted the version of Java in which they appeared to demonstrate how much change has churned through these classes and interfaces.

diagram showing the various string-related classes and interfaces as of Java 8

Text Blocks

Other than adding more Unicode characters including a multitude of emoji, in recent years not much has changed in Java for working with text. Until text blocks.

Text blocks are a new way of better handling the tedium of string literals with multiple lines or character-escaping. This would make writing embedded code strings such as HTML, XML, SQL, or JSON much more convenient.

To quote JEP 378:

A text block is a multi-line string literal that avoids the need for most escape sequences, automatically formats the string in a predictable way, and gives the developer control over the format when desired.

The text blocks feature does not introduce a new data type. Text blocks are merely a new syntax for writing a String literal. A text block produces a String object, just like the conventional literal syntax. A text block produces a String object, which is also a CharSequence object, as discussed above.

SQL example

To quote JSR 378 again…

Using "one-dimensional" string literals.

String query = "SELECT \"EMP_ID\", \"LAST_NAME\" FROM \"EMPLOYEE_TB\"\n" +
               "WHERE \"CITY\" = 'INDIANAPOLIS'\n" +
               "ORDER BY \"EMP_ID\", \"LAST_NAME\";\n";

Using a "two-dimensional" block of text

String query = """
               WHERE "CITY" = 'INDIANAPOLIS'
               ORDER BY "EMP_ID", "LAST_NAME";

Text blocks are found in Java 15 and later, per JEP 378: Text Blocks.

First previewed in Java 13, under JEP 355: Text Blocks (Preview). Then previewed again in Java 14 under JEP 368: Text Blocks (Second Preview).

This effort was preceded by JEP 326: Raw String Literals (Preview). The concepts were reworked to produce the Text Blocks feature instead.

Oracle DB: How can I write query ignoring case?

Select * from table where upper( like upper('IgNoreCaSe');

Alternatively, substitute lower for upper.

Linux command-line call not returning what it should from os.system?

For your requirement, Popen function of subprocess python module is the answer. For example,

import subprocess
process = subprocess.Popen("ps -p 2993 -o time --no-headers", stdout=subprocess.PIPE, stderr=subprocess.PIPE)
stdout, stderr = process.communicate()
print stdout

How to Generate a random number of fixed length using JavaScript?

generate a random number that must have a fixed length of exactly 6 digits:


SQL - How do I get only the numbers after the decimal?

one way, works also for negative values

declare @1 decimal(4,3)
select @1 = 2.938

select PARSENAME(@1,1)

Calling Objective-C method from C++ member function?

Step 1

Create a objective c file(.m file) and it's corresponding header file.

// Header file (We call it "ObjCFunc.h")

#ifndef test2_ObjCFunc_h
#define test2_ObjCFunc_h
@interface myClass :NSObject

// Corresponding Objective C file(We call it "ObjCFunc.m")

#import <Foundation/Foundation.h>
#include "ObjCFunc.h"
@implementation myClass
//Your objective c code here....

Step 2

Now we will implement a c++ function to call the objective c function that we just created! So for that we will define a .mm file and its corresponding header file(".mm" file is to be used here because we will be able to use both Objective C and C++ coding in the file)

//Header file(We call it "ObjCCall.h")

#ifndef __test2__ObjCCall__
#define __test2__ObjCCall__
#include <stdio.h>
class ObjCCall
static void objectiveC_Call(); //We define a static method to call the function directly using the class_name
#endif /* defined(__test2__ObjCCall__) */

//Corresponding Objective C++ file(We call it "")

#include "ObjCCall.h"
#include "ObjCFunc.h"
void ObjCCall::objectiveC_Call()
//Objective C code calling.....
myClass *obj=[[myClass alloc]init]; //Allocating the new object for the objective C   class we created
[obj hello:(100)];   //Calling the function we defined

Step 3

Calling the c++ function(which actually calls the objective c method)

#include "cocos2d.h"
#include "ObjCCall.h"
class HelloWorld : public cocos2d::Layer
// there's no 'id' in cpp, so we recommend returning the class instance pointer
static cocos2d::Scene* createScene();
// Here's a difference. Method 'init' in cocos2d-x returns bool, instead of returning  'id' in cocos2d-iphone
virtual bool init();
// a selector callback
void menuCloseCallback(cocos2d::Ref* pSender);
void ObCCall();  //definition
// implement the "static create()" method manually
#endif // __HELLOWORLD_SCENE_H__

//Final call

#include "HelloWorldScene.h"
#include "ObjCCall.h"
Scene* HelloWorld::createScene()
// 'scene' is an autorelease object
auto scene = Scene::create();
// 'layer' is an autorelease object
auto layer = HelloWorld::create();
// add layer as a child to scene
// return the scene
return scene;
// on "init" you need to initialize your instance
bool HelloWorld::init()
// 1. super init first
if ( !Layer::init() )
    return false;
Size visibleSize = Director::getInstance()->getVisibleSize();
Vec2 origin = Director::getInstance()->getVisibleOrigin();

// 2. add a menu item with "X" image, which is clicked to quit the program
//    you may modify it.

// add a "close" icon to exit the progress. it's an autorelease object
auto closeItem = MenuItemImage::create(
                                       CC_CALLBACK_1(HelloWorld::menuCloseCallback,  this));

closeItem->setPosition(Vec2(origin.x + visibleSize.width - closeItem->getContentSize().width/2 ,
                            origin.y + closeItem->getContentSize().height/2));

// create menu, it's an autorelease object
auto menu = Menu::create(closeItem, NULL);
this->addChild(menu, 1);

// 3. add your codes below...

// add a label shows "Hello World"
// create and initialize a label

auto label = Label::createWithTTF("Hello World", "fonts/Marker Felt.ttf", 24);

// position the label on the center of the screen
label->setPosition(Vec2(origin.x + visibleSize.width/2,
                        origin.y + visibleSize.height - label- >getContentSize().height));
// add the label as a child to this layer
this->addChild(label, 1);
// add "HelloWorld" splash screen"
auto sprite = Sprite::create("HelloWorld.png");
// position the sprite on the center of the screen
sprite->setPosition(Vec2(visibleSize.width/2 + origin.x, visibleSize.height/2 +     origin.y));
// add the sprite as a child to this layer
this->addChild(sprite, 0);
this->ObCCall();   //first call
return true;
void HelloWorld::ObCCall()  //Definition
ObjCCall::objectiveC_Call();  //Final Call  
void HelloWorld::menuCloseCallback(Ref* pSender)
MessageBox("You pressed the close button. Windows Store Apps do not implement a close    button.","Alert");

Hope this works!

Entity Framework and Connection Pooling

Below code helped my object to be refreshed with fresh database values. The Entry(object).Reload() command forces the object to recall database values

GM_MEMBERS member = DatabaseObjectContext.GM_MEMBERS.FirstOrDefault(p => p.Username == username && p.ApplicationName == this.ApplicationName);

how to configure apache server to talk to HTTPS backend server?

In my case, my server was configured to work only in https mode, and error occured when I try to access http mode. So changing http://my-service to https://my-service helped.

Convert string to date in bash

We can use date -d option

1) Change format to "%Y-%m-%d" format i.e 20121212 to 2012-12-12

date -d '20121212' +'%Y-%m-%d'

2)Get next or last day from a given date=20121212. Like get a date 7 days in past with specific format

date -d '20121212 -7 days' +'%Y-%m-%d'

3) If we are getting date in some variable say dat

dat2=$(date -d "$dat -1 days" +'%Y%m%d')

Best programming based games

The game in question was definitely Robowar for the Mac. My son had a lot of fun with it and went on to program real robots.

As mentioned earlier by Proud, there is a wiki page for it:

Although there has not been a lot of activity surrounding the game over the last few years, there was a tournament held recently, and there is a yahoo email group.

MVC ajax post to controller action method

$('#loginBtn').click(function(e) {
    e.preventDefault(); /// it should not have this code or else it wont continue

'ssh-keygen' is not recognized as an internal or external command

I found an easy solution to fix this :

In the command prompt, go to your git\bin directory, and then execute your commands from here

Subset of rows containing NA (missing) values in a chosen column of a data frame

Never use =='NA' to test for missing values. Use instead. This should do it:

new_DF <- DF[rowSums( > 0,]

or in case you want to check a particular column, you can also use

new_DF <- DF[$Var),]

In case you have NA character values, first run

Df[Df=='NA'] <- NA

to replace them with missing values.

How do I break a string across more than one line of code in JavaScript?

In your example, you can break the string into two pieces:

alert ( "Please Select file"
 + " to delete");

Or, when it's a string, as in your case, you can use a backslash as @Gumbo suggested:

alert ( "Please Select file\
 to delete");

Note that this backslash approach is not necessarily preferred, and possibly not universally supported (I had trouble finding hard data on this). It is not in the ECMA 5.1 spec.

When working with other code (not in quotes), line breaks are ignored, and perfectly acceptable. For example:

  && SuperLongConditionOnAnotherLine
  && SuperLongConditionOnThirdLineSheesh)
    // launch_missiles();

AngularJS passing data to $http.get request

You can pass params directly to $http.get() The following works fine

$http.get(user.details_path, {
    params: { user_id: }

How to display a gif fullscreen for a webpage background?

In your CSS Style tag put this:

body {
  background: url('yourgif.gif') no-repeat center center fixed;
  background-size: cover;

Adding two numbers concatenates them instead of calculating the sum

You need to use javaScript's parseInt() method to turn the strings back into numbers. Right now they are strings so adding two strings concatenates them, which is why you're getting "12".

Mysql database sync between two databases

SymmetricDS is the answer. It supports multiple subscribers with one direction or bi-directional asynchronous data replication. It uses web and database technologies to replicate tables between relational databases, in near real time if desired.

Comprehensive and robust Java API to suit your needs.

When to use in vs ref vs out

Extra notes regarding C# 7:
In C# 7 there's no need to predeclare variables using out. So a code like this:

public void PrintCoordinates(Point p)
  int x, y; // have to "predeclare"
  p.GetCoordinates(out x, out y);
  WriteLine($"({x}, {y})");

Can be written like this:

public void PrintCoordinates(Point p)
  p.GetCoordinates(out int x, out int y);
  WriteLine($"({x}, {y})");

Source: What's new in C# 7.

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

It depends why the something is on the same line in the first place.

clear in the case of floats, display: block in the case of inline content naturally flowing, nothing will defeat position: absolute as the previous element will be taken out of the normal flow by it.

Passing a URL with brackets to curl

Never mind, I found it in the docs:

              This  option  switches  off  the "URL globbing parser". When you set this option, you can
              specify URLs that contain the letters {}[] without having them being interpreted by  curl
              itself.  Note  that  these  letters  are not normal legal URL contents but they should be
              encoded according to the URI standard.

Detect whether a Python string is a number or a letter

For a string of length 1 you can simply perform isdigit() or isalpha()

If your string length is greater than 1, you can make a function something like..

def isinteger(a):
        return True
    except ValueError:
        return False

Define a fixed-size list in Java

This should do it if memory serves:

List<MyType> fixed = Arrays.asList(new MyType[100]);

Copy folder structure (without files) from one location to another

Here is a solution in php that:

  • copies the directories (not recursively, only one level)
  • preserves permissions
  • unlike the rsync solution, is fast even with directories containing thousands of files as it does not even go into the folders
  • has no problems with spaces
  • should be easy to read and adjust

Create a file like syncDirs.php with this content:

foreach (new DirectoryIterator($argv[1]) as $f) {
    if($f->isDot() || !$f->isDir()) continue;
        mkdir($argv[2].'/'.$f->getFilename(), $f->getPerms());
        chown($argv[2].'/'.$f->getFilename(), $f->getOwner());
        chgrp($argv[2].'/'.$f->getFilename(), $f->getGroup());

Run it as user that has enough rights:

sudo php syncDirs.php /var/source /var/destination

how to use free cloud database with android app?

As Wingman said, Google App Engine is a great solution for your scenario.

You can get some information about GAE+Android here:

And from this Google IO 2012 session:

WPF button click in C# code

You should place below line

btn.Click = btn.Click + btn1_Click;

Of Countries and their Cities

There are quite a few available.

The following has database for 2,401,039 cities

file_get_contents() how to fix error "Failed to open stream", "No such file"

You may try using this

$json = json_decode(file_get_contents('./*key*'));

The "./" allows to search url from current directory. You may use


to change current working directory to root of your website if path is relative from root directory.

Why should I use a pointer rather than the object itself?

Well the main question is Why should I use a pointer rather than the object itself? And my answer, you should (almost) never use pointer instead of object, because C++ has references, it is safer then pointers and guarantees the same performance as pointers.

Another thing you mentioned in your question:

Object *myObject = new Object;

How does it work? It creates pointer of Object type, allocates memory to fit one object and calls default constructor, sounds good, right? But actually it isn't so good, if you dynamically allocated memory (used keyword new), you also have to free memory manually, that means in code you should have:

delete myObject;

This calls destructor and frees memory, looks easy, however in big projects may be difficult to detect if one thread freed memory or not, but for that purpose you can try shared pointers, these slightly decreases performance, but it is much easier to work with them.

And now some introduction is over and go back to question.

You can use pointers instead of objects to get better performance while transferring data between function.

Take a look, you have std::string (it is also object) and it contains really much data, for example big XML, now you need to parse it, but for that you have function void foo(...) which can be declarated in different ways:

  1. void foo(std::string xml); In this case you will copy all data from your variable to function stack, it takes some time, so your performance will be low.
  2. void foo(std::string* xml); In this case you will pass pointer to object, same speed as passing size_t variable, however this declaration has error prone, because you can pass NULL pointer or invalid pointer. Pointers usually used in C because it doesn't have references.
  3. void foo(std::string& xml); Here you pass reference, basically it is the same as passing pointer, but compiler does some stuff and you cannot pass invalid reference (actually it is possible to create situation with invalid reference, but it is tricking compiler).
  4. void foo(const std::string* xml); Here is the same as second, just pointer value cannot be changed.
  5. void foo(const std::string& xml); Here is the same as third, but object value cannot be changed.

What more I want to mention, you can use these 5 ways to pass data no matter which allocation way you have chosen (with new or regular).

Another thing to mention, when you create object in regular way, you allocate memory in stack, but while you create it with new you allocate heap. It is much faster to allocate stack, but it is kind a small for really big arrays of data, so if you need big object you should use heap, because you may get stack overflow, but usually this issue is solved using STL containers and remember std::string is also container, some guys forgot it :)

System.IO.FileNotFoundException: Could not load file or assembly 'X' or one of its dependencies when deploying the application

's up guys i read every single forum about this topic i still had problem (occurred trying to project from git)

after 4 hours and a lot of swearing i solved this issue by myself just by changing target framework setting in project properties (right click on project -> properties) -> application and changed target framework from .net core 3.0 to .net 5.0 i hope it will help anybody

happy coding gl hf nerds

Running a Python script from PHP

If you want to know the return status of the command and get the entire stdout output you can actually use exec:

$command = 'ls';
exec($command, $out, $status);

$out is an array of all lines. $status is the return status. Very useful for debugging.

If you also want to see the stderr output you can either play with proc_open or simply add 2>&1 to your $command. The latter is often sufficient to get things working and way faster to "implement".

How to get the date and time values in a C program?

I'm getting the following error when compiling Adam Rosenfield's code on Windows. It turns out few things are missing from the code.

Error (Before)

C:\C\Codes>gcc time.c -o time
time.c:3:12: error: initializer element is not constant
 time_t t = time(NULL);
time.c:4:16: error: initializer element is not constant
 struct tm tm = *localtime(&t);
time.c:6:8: error: expected declaration specifiers or '...' before string constant
 printf("now: %d-%d-%d %d:%d:%d\n", tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, tm.tm_hour, tm.tm_min, tm.tm_sec);
time.c:6:36: error: expected declaration specifiers or '...' before 'tm'
 printf("now: %d-%d-%d %d:%d:%d\n", tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, tm.tm_hour, tm.tm_min, tm.tm_sec);
time.c:6:55: error: expected declaration specifiers or '...' before 'tm'
 printf("now: %d-%d-%d %d:%d:%d\n", tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, tm.tm_hour, tm.tm_min, tm.tm_sec);
time.c:6:70: error: expected declaration specifiers or '...' before 'tm'
 printf("now: %d-%d-%d %d:%d:%d\n", tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, tm.tm_hour, tm.tm_min, tm.tm_sec);
time.c:6:82: error: expected declaration specifiers or '...' before 'tm'
 printf("now: %d-%d-%d %d:%d:%d\n", tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, tm.tm_hour, tm.tm_min, tm.tm_sec);
time.c:6:94: error: expected declaration specifiers or '...' before 'tm'
 printf("now: %d-%d-%d %d:%d:%d\n", tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, tm.tm_hour, tm.tm_min, tm.tm_sec);
time.c:6:105: error: expected declaration specifiers or '...' before 'tm'
 printf("now: %d-%d-%d %d:%d:%d\n", tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, tm.tm_hour, tm.tm_min, tm.tm_sec);


C:\C\Codes>more time.c
#include <stdio.h>
#include <time.h>

int main()
        time_t t = time(NULL);
        struct tm tm = *localtime(&t);

        printf("now: %d-%d-%d %d:%d:%d\n", tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, tm.tm_hour, tm.tm_min, tm.tm_sec);



C:\C\Codes>gcc time.c -o time


Final Output

now: 2018-3-11 15:46:36


I hope this will helps others too

Nested Recycler view height doesn't wrap its content

Simply wrap the content using RecyclerView with the Grid Layout

Image: Recycler as GridView layout

Just use the GridLayoutManager like this:

RecyclerView.LayoutManager mRecyclerGrid=new GridLayoutManager(this,3,LinearLayoutManager.VERTICAL,false);

You can set how many items should appear on a row (replace the 3).

How to echo out the values of this array?

you need the set key and value in foreach loop for that:

foreach($item AS $key -> $value) {
echo $value;

this should do the trick :)

Using CSS in Laravel views?

put your css in public folder, then

add this in you blade file

<link rel="stylesheet" type="text/css" href="{{ asset('mystyle.css') }}">

How to get a value from a Pandas DataFrame and not the index and object type

Nobody mentioned it, but you can also simply use loc with the index and column labels.

df.loc[2, 'Letters']
# 'C'

Or, if you prefer to use "Numbers" column as reference, you can also set is as an index.

df.set_index('Numbers').loc[3, 'Letters']

WPF Datagrid Get Selected Cell Value

If SelectionUnit="Cell" try this:

    string cellValue = GetSelectedCellValue();


    public string GetSelectedCellValue()
        DataGridCellInfo cellInfo = MyDataGrid.SelectedCells[0];
        if (cellInfo == null) return null;

        DataGridBoundColumn column = cellInfo.Column as DataGridBoundColumn;
        if (column == null) return null;

        FrameworkElement element = new FrameworkElement() { DataContext = cellInfo.Item };
        BindingOperations.SetBinding(element, TagProperty, column.Binding);

        return element.Tag.ToString();

Seems like it shouldn't be that complicated, I know...

Edit: This doesn't seem to work on DataGridTemplateColumn type columns. You could also try this if your rows are made up of a custom class and you've assigned a sort member path:

    public string GetSelectedCellValue()
        DataGridCellInfo cells = MyDataGrid.SelectedCells[0];

        YourRowClass item = cells.Item as YourRowClass;
        string columnName = cells.Column.SortMemberPath;

        if (item == null || columnName == null) return null;

        object result = item.GetType().GetProperty(columnName).GetValue(item, null);

        if (result == null) return null;

        return result.ToString();

PHP reindex array?

array_values does the job :

$myArray  = array_values($myArray);

Also some other php function do not preserve the keys, i.e. reset the index.

Adding/removing items from a JavaScript object with jQuery

If you are using jQuery you can use the extend function to add new items.

var olddata = {"fruit":{"apples":10,"pears":21}};

var newdata = {};
newdata['vegetables'] = {"carrots": 2, "potatoes" : 5};

$.extend(true, olddata, newdata);

This will generate:

{"fruit":{"apples":10,"pears":21}, "vegetables":{"carrots":2,"potatoes":5}};

How to get Client location using Google Maps API v3?

A bit late but I got something similar that I'm busy building and here is the code to get current location - be sure to use local server to test.

Include relevant scripts from CDN:

    <script type="text/javascript" src="">


<div id="map"></div>


html, body {
    height: 100%;
    margin: 0;
    padding: 0;
#map {
    height: 100%;


var map = new google.maps.Map(document.getElementById('map'), {
    center: {lat: -34.397, lng: 150.644},
    zoom: 6
var infoWindow = new google.maps.InfoWindow({map: map});

// Try HTML5 geolocation.
if (navigator.geolocation) {
    navigator.geolocation.getCurrentPosition(function(position) {
        var pos = {
            lat: position.coords.latitude,
            lng: position.coords.longitude

        infoWindow.setContent('Location found.');
    }, function() {
        handleLocationError(true, infoWindow, map.getCenter());
} else {
    // Browser doesn't support Geolocation
    handleLocationError(false, infoWindow, map.getCenter());

function handleLocationError(browserHasGeolocation, infoWindow, pos) {
    infoWindow.setContent(browserHasGeolocation ?
                          'Error: The Geolocation service failed.' :
                          'Error: Your browser doesn\'t support geolocation.');


Can Windows Containers be hosted on linux?

Solution 1 - Using VirtualBox

As Muhammad Sahputra suggested in this post, it is possible to run Windows OS inside VirtualBox (using VBoxHeadless - without graphical interface) inside Docker container.

Also, a NAT setup inside the VM network configurations can do a port forwarding which gives you the ability to pass-through any traffic that comes to and from the Docker container. This eventually, in a wide perspective, allows you to run any Windows-based service on top of Linux machine.

Maybe this is not a typical use-case of a Docker container, but it definitely an interesting approach to the problem.

Solution 2 - Using Wine

For simple applications and maybe more complicated, you can try to use wine inside a docker container.

This docker hub page may help you to achieve your goal.

I hope that Docker will release a native solution soon, like they did with docker-machine on Windows several years ago.

Where's javax.servlet?

A bit more detail to Joachim Sauer's answer:

On Ubuntu at least, the metapackage tomcat6 depends on metapackage tomcat6-common (and others), which depends on metapackage libtomcat6-java, which depends on package libservlet2.5-java (and others). It contains, among others, the files /usr/share/java/servlet-api-2.5.jar and /usr/share/java/jsp-api-2.1.jar, which are the servlet and JSP libraries you need. So if you've installed Tomcat 6 through apt-get or the Ubuntu Software Centre, you already have the libraries; all that's left is to get Tomcat to use them in your project.

Place libraries /usr/share/java/servlet-api-2.5.jar and /usr/share/java/jsp-api-2.1.jar on the class path like this:

  • For all projects, by configuring Eclipse by selecting Window -> Preferences -> Java -> Installed JREs, then selecting the JRE you're using, pressing Edit, then pressing Add External JARs, and then by selecting the files from the locations given above.

  • For just one project, by right-clicking on the project in the Project Explorer pane, then selecting Properties -> Java Build Path, and then pressing Add External JARs, and then by selecting the files from the locations given above.

Further note 1: These are the correct versions of those libraries for use with Tomcat 6; for the other Tomcat versions, see the table on page, though I would suppose each Tomcat version includes the versions of these libraries that are appropriate for it.

Further note 2: Package libservlet2.5-java's description (dpkg-query -s libservlet2.5-java) says: 'Apache Tomcat implements the Java Servlet and the JavaServer Pages (JSP) specifications from Sun Microsystems, and provides a "pure Java" HTTP web server environment for Java code to run. This package contains the Java Servlet and JSP library.'

Sorting a Python list by two fields

In ascending order you can use:

sorted_data= sorted(non_sorted_data, key=lambda k: (k[1],k[0]))

or in descending order you can use:

sorted_data= sorted(non_sorted_data, key=lambda k: (k[1],k[0]),reverse=True)

How to run html file on localhost?

You can try installing one of the following localhost softwares:

  1. xampp
  2. wamp
  3. ammps server
  4. laragon

There are many more such softwares but the best among them are the ones mentioned above. they also allow domain names (for example:

How to discover number of *logical* cores on Mac OS X?


When this question was asked the OP did not say that he wanted the number of LOGICAL cores rather than the actual number of cores, so this answer logically (no pun intended) answers with a way to get the actual number of real physical cores, not the number that the OS tries to virtualize through hyperthreading voodoo.


Due to a weird bug in OS X Yosemite (and possibly newer versions, such as the upcoming El Capitan), I've made a small modification. (The old version still worked perfectly well if you just ignore STDERR, which is all the modification does for you.)

Every other answer given here either

  1. gives incorrect information
  2. gives no information, due to an error in the command implementation
  3. runs unbelievably slowly (taking the better part of a minute to complete), or
  4. gives too much data, and thus might be useful for interactive use, but is useless if you want to use the data programmatically (for instance, as input to a command like bundle install --jobs 3 where you want the number in place of 3 to be one less than the number of cores you've got, or at least not more than the number of cores)

The way to get just the number of cores, reliably, correctly, reasonably quickly, and without extra information or even extra characters around the answer, is this:

system_profiler SPHardwareDataType 2> /dev/null | grep 'Total Number of Cores' | cut -d: -f2 | tr -d ' '

Tomcat: java.lang.IllegalArgumentException: Invalid character found in method name. HTTP method names must be tokens

You can also try turning off the SSL option in settings, in case you are sending it through POSTMAN

How to use FormData for AJAX file upload?

$(document).ready(function () {
    $(".submit_btn").click(function (event) {
        var form = $('#fileUploadForm')[0];
        var data = new FormData(form);
        data.append("CustomField", "This is some extra data, testing");
        $("#btnSubmit").prop("disabled", true);
            type: "POST",
            enctype: 'multipart/form-data',
            url: "upload.php",
            data: data,
            processData: false,
            contentType: false,
            cache: false,
            timeout: 600000,
            success: function (data) {

Fastest Convert from Collection to List<T>

managementObjects.Cast<ManagementBaseObject>().ToList(); is a good choice.

You could improve performance by pre-initialising the list capacity:

    public static class Helpers
        public static List<T> CollectionToList<T>(this System.Collections.ICollection other)
            var output = new List<T>(other.Count);


            return output;

Is there a format code shortcut for Visual Studio?

Select all text in the document and press Ctrl + E + D.

Output (echo/print) everything from a PHP Array

You can use print_r to get human-readable output.


kill -3 to get java thread dump

There is a way to redirect JVM thread dump output on break signal to separate file with LogVMOutput diagnostic option:

-XX:+UnlockDiagnosticVMOptions -XX:+LogVMOutput -XX:LogFile=jvm.log

Calling a function every 60 seconds

A better use of jAndy's answer to implement a polling function that polls every interval seconds, and ends after timeout seconds.

function pollFunc(fn, timeout, interval) {
    var startTime = (new Date()).getTime();
    interval = interval || 1000;

    (function p() {
        if (((new Date).getTime() - startTime ) <= timeout)  {
            setTimeout(p, interval);

pollFunc(sendHeartBeat, 60000, 1000);


As per the comment, updating it for the ability of the passed function to stop the polling:

function pollFunc(fn, timeout, interval) {
    var startTime = (new Date()).getTime();
    interval = interval || 1000,
    canPoll = true;

    (function p() {
        canPoll = ((new Date).getTime() - startTime ) <= timeout;
        if (!fn() && canPoll)  { // ensures the function exucutes
            setTimeout(p, interval);

pollFunc(sendHeartBeat, 60000, 1000);

function sendHeartBeat(params) {
    if (receivedData) {
        // no need to execute further
        return true; // or false, change the IIFE inside condition accordingly.

Allow Access-Control-Allow-Origin header using HTML5 fetch API

If you are use nginx try this

#Control-Allow-Origin access

    # Authorization headers aren't passed in CORS preflight (OPTIONS) calls. Always return a 200 for options.
    add_header Access-Control-Allow-Credentials "true" always;
    add_header Access-Control-Allow-Origin "https://URL-WHERE-ORIGIN-FROM-HERE " always;
    add_header Access-Control-Allow-Methods "GET,OPTIONS" always;
    add_header Access-Control-Allow-Headers "x-csrf-token,authorization,content-type,accept,origin,x-requested-with,access-control-allow-origin" always;

    if ($request_method = OPTIONS ) {
        return 200;

Start an external application from a Google Chrome Extension?

Previously, you would do this through NPAPI plugins.

However, Google is now phasing out NPAPI for Chrome, so the preferred way to do this is using the native messaging API. The external application would have to register a native messaging host in order to exchange messages with your application.

Can jQuery get all CSS styles associated with an element?

@marknadal's solution wasn't grabbing hyphenated properties for me (e.g. max-width), but changing the first for loop in css2json() made it work, and I suspect performs fewer iterations:

for (var i = 0; i < css.length; i += 1) {
    s[css[i]] = css.getPropertyValue(css[i]);

Loops via length rather than in, retrieves via getPropertyValue() rather than toLowerCase().

Docker is in volume in use, but there aren't any Docker containers

I am fairly new to Docker. I was cleaning up some initial testing mess and was not able to remove a volume either. I had stopped all the running instances, performed a docker rmi -f $(docker image ls -q), but still received the Error response from daemon: unable to remove volume: remove uuid: volume is in use.

I did a docker system prune and it cleaned up what was needed to remove the last volume:

[0]$ docker system prune
WARNING! This will remove:
- all stopped containers
- all networks not used by at least one container
- all dangling images
- all build cache
Are you sure you want to continue? [y/N] y
Deleted Containers:
... about 15 containers UUID's truncated

Total reclaimed space: 2.273MB
[0]$ docker volume ls
local              uuid
[0]$ docker volume rm uuid

docker system prune

The client and daemon API must both be at least 1.25 to use this command. Use the docker version command on the client to check your client and daemon API versions.

.rar, .zip files MIME Type

As extension might contain more or less that three characters the following will test for an extension regardless of the length of it.

Try this:

$allowedExtensions = array( 'mkv', 'mp3', 'flac' );

$temp = explode(".", $_FILES[$file]["name"]);
$extension = strtolower(end($temp));

if( in_array( $extension, $allowedExtensions ) ) { ///

to check for all characters after the last '.'

How to get duplicate items from a list using LINQ?

Here's another option:

var list = new List<string> { "6", "1", "2", "4", "6", "5", "1" };

var set = new HashSet<string>();
var duplicates = list.Where(x => !set.Add(x));

jQuery: How can I show an image popup onclick of the thumbnail?

I was in the same situation and found this one,


Quickly getting to YYYY-mm-dd HH:MM:SS in Perl

Time::Piece (in core since Perl 5.10) also has a strftime function and by default overloads localtime and gmtime to return Time::Piece objects:

use Time::Piece;
print localtime->strftime('%Y-%m-%d');

or without the overridden localtime:

use Time::Piece (); 
print Time::Piece::localtime->strftime('%F %T');

Using "word-wrap: break-word" within a table

table-layout: fixed will get force the cells to fit the table (and not the other way around), e.g.:

<table style="border: 1px solid black; width: 100%; word-wrap:break-word;
              table-layout: fixed;">

EXCEL Multiple Ranges - need different answers for each range



with the range F4:G9:

0   0.1
1   0.15
5   0.2
15  0.3
30  1
100 1.3

and D4 being the value in question, e.g. 18.75 -> result: 0.3

How can you speed up Eclipse?

Disable virus scanners, or at least configure any virus scanner to not scan JAR files on read access.

How to make RatingBar to show five stars

    android:layout_height="wrap_content" >


Select single item from a list

Use the FirstOrDefault selector.

var list = new int[] { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };

var firstEven = list.FirstOrDefault(n => n % 2 == 0);

if (firstEven == 0)
    Console.WriteLine("no even number");
    Console.WriteLine("first even number is {0}", firstEven);

Just pass in a predicate to the First or FirstOrDefault method and it'll happily go round' the list and picks the first match for you.

If there isn't a match, FirstOrDefault will returns the default value of whatever datatype the list items is.

Hope this helps :-)

Replace a newline in TSQL

REPLACE(@string, CHAR(13) + CHAR(10), '')

Hibernate openSession() vs getCurrentSession()

As explained in this forum post, 1 and 2 are related. If you set hibernate.current_session_context_class to thread and then implement something like a servlet filter that opens the session - then you can access that session anywhere else by using the SessionFactory.getCurrentSession().

SessionFactory.openSession() always opens a new session that you have to close once you are done with the operations. SessionFactory.getCurrentSession() returns a session bound to a context - you don't need to close this.

If you are using Spring or EJBs to manage transactions you can configure them to open / close sessions along with the transactions.

You should never use one session per web app - session is not a thread safe object - cannot be shared by multiple threads. You should always use "one session per request" or "one session per transaction"

Split comma-separated values

Split a Textbox value separated by comma and count the total number of values in text and splitted values are shown in ritchTextBox.

    private void button1_Click(object sender, EventArgs e)
        label1.Text = "";
        richTextBox1.Text = "";

        string strText = textBox1.Text.Trim();
        string[] strArr = strText.Split(',');
        int count = 0;
        for (int i = 0; i < strArr.Length; i++)
        label1.Text = Convert.ToString(count);
        for (int i = 0; i < strArr.Length; i++)
            richTextBox1.Text += strArr[i].Trim() + "\n";

Powershell Active Directory - Limiting my get-aduser search to a specific OU [and sub OUs]

If I understand you correctly, you need to use -SearchBase:

Get-ADUser -SearchBase "OU=Accounts,OU=RootOU,DC=ChildDomain,DC=RootDomain,DC=com" -Filter *

Note that Get-ADUser defaults to using

 -SearchScope Subtree

so you don't need to specify it. It's this that gives you all sub-OUs (and sub-sub-OUs, etc.).

Find and replace with sed in directory and sub directories

Your find should look like that to avoid sending directory names to sed:

find ./ -type f -exec sed -i -e 's/apple/orange/g' {} \;

Python Error: "ValueError: need more than 1 value to unpack"

You have to pass the arguments in the terminal in order to store them in 'argv'. This variable holds the arguments you pass to your Python script when you run it. It later unpacks the arguments and store them in different variables you specify in the program e.g.

script, first, second = argv
print "Your file is:", script
print "Your first entry is:", first
print "Your second entry is:" second

Then in your command line you have to run your code like this,

$python Hamburger Pizza

Your output will look like this:

Your file is:
Your first entry is: Hamburger
Your second entry is: Pizza

How to change context root of a dynamic web project in Eclipse?

I'm sure you've moved on by now, but I thought I'd answer anyway.

Some of these answers give workarounds. What actually must happen is that you clean and re-publish your project to "activate" the new URI. This is done by right-clicking your server (in the Servers view) and choosing Clean. Then you start (or restart it). Most of the other answers here suggest you do things that in effect accomplish this.

The file that's changing is workspace/.metadata/.plugins/org.eclipse.wst.server.core/publish/publish.dat unless, that is, you've got more than one server in your workspace in which case it will be publishN.dat on that same path.

Hope this helps somebody.

Not sure if this is proper etiquette or not — I am editing this answer to give exact steps for Eclipse Indigo.

  1. In your project's Properties, choose Web Project Settings.

  2. Change Context root to app.

    screen shot of Eclipse project properties Web Project Settings

  3. Choose Window > Show View > Servers.

  4. Stop the server by either clicking the red square box ("Stop the server" tooltip) or context-click on the server listing to choose "Stop".

  5. On the server you want to use, context-click to choose "Clean…".

    enter image description here

  6. Click OK in this confirmation dialog box.

    Screenshot of dialog asking to update server configuration to match the changed context root

Now you can run your app with the new "app" URL such as:


Doing this outside of Eclipse, on your production server, is even easier --> Rename the war file. Export your Vaadin app as a WAR file (File > Export > Web > WAR file). Move the WAR file to your web server's servlet container such as Tomcat. Rename your WAR file, in this case to app.war. When you start the servlet container, most such as Tomcat will auto-deploy the app, which includes expanding the war file to a folder. In this case, we should see a folder named app. You should be good to go. Test your URL. For a domain such as *" this would be:

Vaadin toolkit programmers may need to rebuild their widget set if using visual add ons.

Android : How to set onClick event for Button in List item of ListView

Class for ArrayList & ArrayAdapter

class RequestClass {
    private String Id;
    private String BookingTime;
    private String UserName;
    private String Rating;

    public RequestClass(String Id,String bookingTime,String userName,String rating){

    public String getId(){return Id; }
    public String getBookingTime(){return BookingTime; }
    public String getUserName(){return UserName; }
    public String getRating(){return Rating; }


Main Activity:

 ArrayList<RequestClass> _requestList;
    _requestList=new ArrayList<>();
                    try {
                        JSONObject jsonobject = new JSONObject(result);
                        JSONArray JO = jsonobject.getJSONArray("Record");
                        JSONObject object;
                        for (int i = 0; i < JO.length(); i++) {
                            object = (JSONObject) JO.get(i);

                            _requestList.add(new RequestClass( object.optString("playerID"),object.optString("booking_time"),
                                    object.optString("username"),object.optString("rate") ));
                        }//end of for loop

                        RequestCustomAdapter adapter = new RequestCustomAdapter(context, R.layout.requestlayout, _requestList);

Custom Adapter Class

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.RelativeLayout;
import android.widget.TextView;
import android.widget.Toast;

import java.util.ArrayList;

 * Created by wajid on 1/12/2018.

class RequestCustomAdapter extends ArrayAdapter<RequestClass> {
    Context mContext;
    int mResource;
    public RequestCustomAdapter(Context context, int resource,ArrayList<RequestClass> objects) {
        super(context, resource, objects);
    public static class ViewHolder{
        RelativeLayout _layout;
        TextView _bookingTime;
        TextView _ratingTextView;
        TextView _userNameTextView;
        Button acceptButton;
        Button _rejectButton;

    public View getView(final int position, View convertView, ViewGroup parent){
       final ViewHolder holder;
        if(convertView == null) {
            LayoutInflater inflater=LayoutInflater.from(mContext);
            holder=new ViewHolder();
            holder._layout = convertView.findViewById(;
            holder._bookingTime = convertView.findViewById(;
            holder._userNameTextView = convertView.findViewById(;
            holder._ratingTextView = convertView.findViewById(;
            holder.acceptButton = convertView.findViewById(;
            holder._rejectButton = convertView.findViewById(;

            holder._rejectButton.setOnClickListener(new View.OnClickListener() {
                public void onClick(View view) {
                    Toast.makeText(mContext, holder._rejectButton.getText().toString(), Toast.LENGTH_SHORT).show();

            holder.acceptButton.setOnClickListener(new View.OnClickListener() {
                public void onClick(View view) {
                    Toast.makeText(mContext, holder.acceptButton.getText().toString(), Toast.LENGTH_SHORT).show();




        return  convertView;


ListView in Main xml:



Resource Layout for list view requestlayout.xml:

        android:text="Temp Name"
        android:text="No Rating"


Set HTML element's style property in javascript

Don't set the style object itself, set the background color property of the style object that is a property of the element.

And yes, even though you said no, jquery and tablesorter with its zebra stripe plugin can do this all for you in 3 lines of code.

And just setting the class attribute would be better since then you have non-hard-coded control over the styling which is more organized

How do I add an existing Solution to GitHub from Visual Studio 2013

None of the answers were specific to my problem, so here's how I did it.

This is for Visual Studio 2015 and I had already made a repository on

If you already have your repository URL copy it and then in visual studio:

  • Go to Team Explorer
  • Click the "Sync" button
  • It should have 3 options listed with "get started" links.
  • I chose the "get started" link against "publish to remote repository", which it the bottom one
  • A yellow box will appear asking for the URL. Just paste the URL there and click publish.

What is the most efficient way to store a list in the Django models?

As this is an old question, and Django techniques must have changed significantly since, this answer reflects Django version 1.4, and is most likely applicable for v 1.5.

Django by default uses relational databases; you should make use of 'em. Map friendships to database relations (foreign key constraints) with the use of ManyToManyField. Doing so allows you to use RelatedManagers for friendlists, which use smart querysets. You can use all available methods such as filter or values_list.

Using ManyToManyField relations and properties:

class MyDjangoClass(models.Model):
    name = models.CharField(...)
    friends = models.ManyToManyField("self")

    def friendlist(self):
        # Watch for large querysets: it loads everything in memory
        return list(self.friends.all())

You can access a user's friend list this way:

joseph = MyDjangoClass.objects.get(name="Joseph")
friends_of_joseph = joseph.friendlist

Note however that these relations are symmetrical: if Joseph is a friend of Bob, then Bob is a friend of Joseph.

Why should I use var instead of a type?

It's really just a coding style. The compiler generates the exact same for both variants.

See also here for the performance question:

Python TypeError: not enough arguments for format string

I got the same error when using % as a percent character in my format string. The solution to this is to double up the %%.

Is it possible to style html5 audio tag?

If you want to style the browsers standard music player in the CSS:

audio {
    enter code here;

Using port number in Windows host file

I managed to achieve this by using Windows included Networking tool netsh.

As Mat points out : The hosts file is for host name resolution only, so a combination of the two did the trick for me.


 |                           <--Link by Hosts File
       |                     <--Link by netsh Utility
       +--> localhost:8081


  • Started my server on localhost:8081
  • Added my "local DNS" in the hosts file as a new line
      • Any free address in the network (127.x.x.x) can be used.
      • Note: I am assuming is not occupied by another service.
      • You can check with netstat -a -n -p TCP | grep "LISTENING"
  • added the following network configuration with netsh command utility
    • netsh interface portproxy add v4tov4 listenport=80 listenaddress= connectport=8081 connectaddress=
  • I can now access the server at

- These commands/file modifications need to be executed with Admin rights

- netsh portproxy needs ipv6 libraries even only to use v4tov4, typically they will also be included by default, otherwise install them using the following command: netsh interface ipv6 install

You can see the entry you have added with the command:

netsh interface portproxy show v4tov4

You can remove the entry with the following command:

netsh interface portproxy delete v4tov4 listenport=80 listenaddress=

Links to Resources:

How to configure Visual Studio to use Beyond Compare

I use BC3 for my git diff, but I'd also add vscode to the list of useful git diff tools. Some users prefer vscode over vs ide experience.

Using VS Code for Git Diff

git config --global diff.tool vscode
git config --global difftool.vscode.cmd "code --wait --diff $LOCAL $REMOTE"

How can I get just the first row in a result set AFTER ordering?

In 12c, here's the new way:

select bla
  from bla
 where bla
 order by finaldate desc
 fetch first 1 rows only; 

How nice is that!

How to set a default value for an existing column

This will work in SQL Server:


Git Push Error: insufficient permission for adding an object to repository database

This can easily happen if you ran git init with a different user from the one you are planning to use when pushing changes.

If you blindly follow the instructions on [1] this will happen as you probably created the git-user as root and then immediately moved on to git init without changing user in between.


Initializing array of structures

There's no "step-by-step" here. When initialization is performed with constant expressions, the process is essentially performed at compile time. Of course, if the array is declared as a local object, it is allocated locally and initialized at run-time, but that can be still thought of as a single-step process that cannot be meaningfully subdivided.

Designated initializers allow you to supply an initializer for a specific member of struct object (or a specific element of an array). All other members get zero-initialized. So, if my_data is declared as

typedef struct my_data {
  int a;
  const char *name;
  double x;
} my_data;

then your

my_data data[]={
    { .name = "Peter" },
    { .name = "James" },
    { .name = "John" },
    { .name = "Mike" }

is simply a more compact form of

my_data data[4]={
    { 0, "Peter", 0 },
    { 0, "James", 0 },
    { 0, "John", 0 },
    { 0, "Mike", 0 }

I hope you know what the latter does.

Transactions in .net

It also depends on what you need. For basic SQL transactions you could try doing TSQL transactions by using BEGIN TRANS and COMMIT TRANS in your code. That is the easiest way but it does have complexity and you have to be careful to commit properly (and rollback).

I would use something like

SQLTransaction trans = null;
using(trans = new SqlTransaction)
    Do SQL stuff here passing my trans into my various SQL executers
    trans.Commit  // May not be quite right

Any failure will pop you right out of the using and the transaction will always commit or rollback (depending on what you tell it to do). The biggest problem we faced was making sure it always committed. The using ensures the scope of the transaction is limited.

Can I change the name of `nohup.out`?

As the file handlers points to i-nodes (which are stored independently from file names) on Linux/Unix systems You can rename the default nohup.out to any other filename any time after starting nohup something&. So also one could do the following:

$ nohup something&
$ mv nohup.out nohup2.out
$ nohup something2&

Now something adds lines to nohup2.out and something2 to nohup.out.

How can I get all sequences in an Oracle database?

select sequence_owner, sequence_name from dba_sequences;

DBA_SEQUENCES -- all sequences that exist 
ALL_SEQUENCES  -- all sequences that you have permission to see 
USER_SEQUENCES  -- all sequences that you own

Note that since you are, by definition, the owner of all the sequences returned from USER_SEQUENCES, there is no SEQUENCE_OWNER column in USER_SEQUENCES.

Get max and min value from array in JavaScript

Find largest and smallest number in an array with lodash.

var array = [1, 3, 2];_x000D_
var func = _.over(Math.max, Math.min);_x000D_
var [max, min] = func(...array);_x000D_
// => [3, 1]_x000D_
<script src=""></script>

How do I print the percent sign(%) in c

Try printing out this way


How to put more than 1000 values into an Oracle IN clause

I wound up here looking for a solution as well.

Depending on the high-end number of items you need to query against, and assuming your items are unique, you could split your query into batches queries of 1000 items, and combine the results on your end instead (pseudocode here):

//remove dupes
items = items.RemoveDuplicates();

//how to break the items into 1000 item batches        
batches = new batch list;
batch = new batch;
for (int i = 0; i < items.Count; i++)
    if (batch.Count == 1000)
    if (i == items.Count - 1)
        //add the final batch (it has < 1000 items).

// now go query the db for each batch
results = new results;
foreach(batch in batches)

This may be a good trade-off in the scenario where you don't typically have over 1000 items - as having over 1000 items would be your "high end" edge-case scenario. For example, in the event that you have 1500 items, two queries of (1000, 500) wouldn't be so bad. This also assumes that each query isn't particularly expensive in of its own right.

This wouldn't be appropriate if your typical number of expected items got to be much larger - say, in the 100000 range - requiring 100 queries. If so, then you should probably look more seriously into using the global temporary tables solution provided above as the most "correct" solution. Furthermore, if your items are not unique, you would need to resolve duplicate results in your batches as well.

Async await in linq select

I prefer this as an extension method:

public static async Task<IEnumerable<T>> WhenAll<T>(this IEnumerable<Task<T>> tasks)
    return await Task.WhenAll(tasks);

So that it is usable with method chaining:

var inputs = await events
  .Select(async ev => await ProcessEventAsync(ev))

jQuery how to bind onclick event to dynamically added HTML element

All of these methods are deprecated. You should use the on method to solve your problem.

If you want to target a dynamically added element you'll have to use

$(document).on('click', selector-to-your-element , function() {
     //code here ....

this replace the deprecated .live() method.

Using dig to search for SPF records

The dig utility is pretty convenient to use. The order of the arguments don't really matter.I'll show you some easy examples.
To get all root name servers use

# dig

To get a TXT record of a specific host use

# dig txt
# dig txt

To query a specific name server just add @nameserver.tld

# dig txt

The SPF RFC4408 says that SPF records can be stored as SPF or TXT. However nearly all use only TXT records at the moment. So you are pretty safe if you only fetch TXT records.

I made a SPF checker for visualising the SPF records of a domain. It might help you to understand SPF records better. You can find it here:

Access elements of parent window from iframe

You can access elements of parent window from within an iframe by using window.parent like this:

// using jquery    

Which is the same as:

// pure javascript

And if you have more than one nested iframes and you want to access the topmost iframe, then you can use like this:

// using jquery$("#element_id");

Which is the same as:

// pure javascript"element_id");

Guzzle 6: no more json() method for responses

I use json_decode($response->getBody()) now instead of $response->json().

I suspect this might be a casualty of PSR-7 compliance.

Auto-increment on partial primary key with Entity Framework Core

Specifying the column type as serial for PostgreSQL to generate the id.

[Column(Order=1, TypeName="serial")]
public int ID { get; set; }

Binding value to input in Angular JS

Some times there are problems with funtion/features that do not interact with the DOM

try to change the value sharply and then assign the $scope

document.getElementById ("textWidget") value = "<NewVal>";
$scope.widget.title = "<NewVal>";

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

My device is POSITIVO and my operational system is Ubuntu 14.04 LTS So, my problem was in variable name

I create the file /etc/udev/rules.d/51-android.rules and put SUBSYSTEM=="usb", SYSFS{idVendor}=="1662", MODE="0666"

I disconnected device and execute:

$ sudo udevadm control --reload-rules
$ sudo service udev restart

after this i connected the android device in developer mode again and

$ adb devices

List of devices attached 
1A883XB1K   device

Why doesn't Dijkstra's algorithm work for negative weight edges?

Recall that in Dijkstra's algorithm, once a vertex is marked as "closed" (and out of the open set) - the algorithm found the shortest path to it, and will never have to develop this node again - it assumes the path developed to this path is the shortest.

But with negative weights - it might not be true. For example:

      / \
     /   \
    /     \
   5       2
  /         \

V={A,B,C} ; E = {(A,C,2), (A,B,5), (B,C,-10)}

Dijkstra from A will first develop C, and will later fail to find A->B->C

EDIT a bit deeper explanation:

Note that this is important, because in each relaxation step, the algorithm assumes the "cost" to the "closed" nodes is indeed minimal, and thus the node that will next be selected is also minimal.

The idea of it is: If we have a vertex in open such that its cost is minimal - by adding any positive number to any vertex - the minimality will never change.
Without the constraint on positive numbers - the above assumption is not true.

Since we do "know" each vertex which was "closed" is minimal - we can safely do the relaxation step - without "looking back". If we do need to "look back" - Bellman-Ford offers a recursive-like (DP) solution of doing so.

Date format in dd/MM/yyyy hh:mm:ss



Editing specific line in text file in Python

def replace_line(file_name, line_num, text):
    lines = open(file_name, 'r').readlines()
    lines[line_num] = text
    out = open(file_name, 'w')

And then:

replace_line('stats.txt', 0, 'Mage')

Using SSIS BIDS with Visual Studio 2012 / 2013

Welcome to Microsoft Marketing Speak hell. With the 2012 release of SQL Server, the BIDS, Business Intelligence Designer Studio, plugin for Visual Studio was renamed to SSDT, SQL Server Data Tools. SSDT is available for 2010 and 2012. The problem is, there are two different products called SSDT.

There is SSDT which replaces the database designer thing which was called Data Dude in VS 2008 and in 2010 became database projects. That a free install and if you snag the web installer, that's what you get when you install SSDT. It puts the correct project templates and such into Visual Studio.

There's also the SSDT which is the "BIDS" replacement for developing SSIS, SSRS and SSAS stuff. As of March 2013, it is now available for the 2012 release of Visual Studio. The download is labeled SSDTBI_VS2012_X86.msi Perhaps that's a signal on how the product is going to be referred to in marketing materials. Download links are

None the less, we have Business Intelligence projects available to us in Visual Studio 2012. And the people did rejoice and did feast upon the lambs and toads and tree-sloths and fruit-bats and orangutans and breakfast cereals

enter image description here

How to add text to an existing div with jquery

Very easy from My side:-

    $(document).ready(function() {
        $("input").click(function() {
            $('<input type="text" name="name" value="value"/>').appendTo('#testdiv');

<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
    <div id="testdiv"></div>
    <input type="button" value="Add" />

Getting the folder name from a path

string Folder = Directory.GetParent(path).Name;

Iterate through a C array

It depends. If it's a dynamically allocated array, that is, you created it calling malloc, then as others suggest you must either save the size of the array/number of elements somewhere or have a sentinel (a struct with a special value, that will be the last one).

If it's a static array, you can sizeof it's size/the size of one element. For example:

int array[10], array_size;
array_size = sizeof(array)/sizeof(int);

Note that, unless it's global, this only works in the scope where you initialized the array, because if you past it to another function it gets decayed to a pointer.

Hope it helps.

How to copy multiple files in one layer using a Dockerfile?


COPY  package.json gulpfile.js __BUILD_NUMBER ./

from the doc

If multiple resources are specified, either directly or due to the use of a wildcard, then must be a directory, and it must end with a slash /.

Storing database records into array


// run query
$query = mysql_query("SELECT * FROM table");

// set array
$array = array();

// look through query
while($row = mysql_fetch_assoc($query)){

  // add each row returned into an array
  $array[] = $row;

  // OR just echo the data:
  echo $row['username']; // etc


// debug:
print_r($array); // show all array data
echo $array[0]['username']; // print the first rows username

How to make rounded percentages add up to 100%

I once wrote an unround tool, to find the minimal perturbation to a set of numbers to match a goal. It was a different problem, but one could in theory use a similar idea here. In this case, we have a set of choices.

Thus for the first element, we can either round it up to 14, or down to 13. The cost (in a binary integer programming sense) of doing so is less for the round up than the round down, because the round down requires we move that value a larger distance. Similarly, we can round each number up or down, so there are a total of 16 choices we must choose from.

+ 28.788024

I'd normally solve the general problem in MATLAB, here using bintprog, a binary integer programming tool, but there are only a few choices to be tested, so it is easy enough with simple loops to test out each of the 16 alternatives. For example, suppose we were to round this set as:

 Original      Rounded   Absolute error
   13.626           13          0.62633
    47.99           48          0.01036
    9.596           10          0.40399
 + 28.788           29          0.21198
  100.000          100          1.25266

The total absolute error made is 1.25266. It can be reduced slightly by the following alternative rounding:

 Original      Rounded   Absolute error
   13.626           14          0.37367
    47.99           48          0.01036
    9.596            9          0.59601
 + 28.788           29          0.21198
  100.000          100          1.19202

In fact, this will be the optimal solution in terms of the absolute error. Of course, if there were 20 terms, the search space will be of size 2^20 = 1048576. For 30 or 40 terms, that space will be of significant size. In that case, you would need to use a tool that can efficiently search the space, perhaps using a branch and bound scheme.

How to get index of an item in java.util.Set

you can extend LinkedHashSet adding your desired getIndex() method. It's 15 minutes to implement and test it. Just go through the set using iterator and counter, check the object for equality. If found, return the counter.

JavaFX Location is not set error message

I was getting this exception and the "solution" I found was through Netbeans IDE, simply:

  1. Right-click -> "Clean and Build"
  2. Run project again

I don't know WHY this worked, but it did!

How to compare LocalDate instances Java 8

I believe this snippet will also be helpful in a situation where the dates comparison spans more than two entries.

static final int COMPARE_EARLIEST = 0;

static final int COMPARE_MOST_RECENT = 1;

public LocalDate getTargetDate(List<LocalDate> datesList, int comparatorType) { 
   LocalDate refDate = null;
       case COMPARE_EARLIEST:         
       //returns the most earliest of the date entries
          refDate = (LocalDate) -> 

          //returns the most recent of the date entries 
          refDate = (LocalDate) -> 

   return refDate;

HTML5 Canvas Rotate Image

This is full degree image rotation code. I recommend you to check the below example app in the jsfiddle.

enter image description here

The process flow of this example app is

  1. load Image, calculate boundaryRad
  2. create temporary canvas
  3. move canvas context origin to joint position of the projected rect
  4. rotate canvas context with input degree amount
  5. use canvas.toDataURL method to make image blob
  6. using image blob, create new Image element and render

function init() {
  image.onload = function() {
     app.boundaryRad = Math.atan(image.width / image.height);

 * NOTE : When source rect is rotated at some rad or degrees, 
 * it's original width and height is no longer usable in the rendered page.
 * So, calculate projected rect size, that each edge are sum of the 
 * width projection and height projection of the original rect.
function calcProjectedRectSizeOfRotatedRect(size, rad) {
  const { width, height } = size;

  const rectProjectedWidth = Math.abs(width * Math.cos(rad)) + Math.abs(height * Math.sin(rad));
  const rectProjectedHeight = Math.abs(width * Math.sin(rad)) + Math.abs(height * Math.cos(rad));

  return { width: rectProjectedWidth, height: rectProjectedHeight };

 * @callback rotatedImageCallback
 * @param {DOMString} dataURL - return value of canvas.toDataURL()

 * @param {HTMLImageElement} image 
 * @param {object} angle
 * @property {number} 
 * @property {number} angle.rad
 * @param {rotatedImageCallback} cb
function getRotatedImage(image, angle, cb) {
  const canvas = document.createElement('canvas');
  const { degree, rad: _rad } = angle;

  const rad = _rad || degree * Math.PI / 180 || 0;
  debug('rad', rad);

  const { width, height } = calcProjectedRectSizeOfRotatedRect(
    { width: image.width, height: image.height }, rad
  debug('image size', image.width, image.height);
  debug('projected size', width, height);

  canvas.width = Math.ceil(width);
  canvas.height = Math.ceil(height);

  const ctx = canvas.getContext('2d');;

  const sin_Height = image.height * Math.abs(Math.sin(rad))
  const cos_Height = image.height * Math.abs(Math.cos(rad))
  const cos_Width = image.width * Math.abs(Math.cos(rad))
  const sin_Width = image.width * Math.abs(Math.sin(rad))

  debug('sin_Height, cos_Width', sin_Height, cos_Width);
  debug('cos_Height, sin_Width', cos_Height, sin_Width);

  let xOrigin, yOrigin;

  if (rad < app.boundaryRad) {
    xOrigin = Math.min(sin_Height, cos_Width);
    yOrigin = 0;
  } else if (rad < Math.PI / 2) {
    xOrigin = Math.max(sin_Height, cos_Width);
    yOrigin = 0;
  } else if (rad < Math.PI / 2 + app.boundaryRad) {
    xOrigin = width;
    yOrigin = Math.min(cos_Height, sin_Width);
  } else if (rad < Math.PI) {
    xOrigin = width;
    yOrigin = Math.max(cos_Height, sin_Width);
  } else if (rad < Math.PI + app.boundaryRad) {
    xOrigin = Math.max(sin_Height, cos_Width);
    yOrigin = height;
  } else if (rad < Math.PI / 2 * 3) {
    xOrigin = Math.min(sin_Height, cos_Width);
    yOrigin = height;
  } else if (rad < Math.PI / 2 * 3 + app.boundaryRad) {
    xOrigin = 0;
    yOrigin = Math.max(cos_Height, sin_Width);
  } else if (rad < Math.PI * 2) {
    xOrigin = 0;
    yOrigin = Math.min(cos_Height, sin_Width);

  debug('xOrigin, yOrigin', xOrigin, yOrigin)

  ctx.translate(xOrigin, yOrigin)
  ctx.drawImage(image, 0, 0);
  if (DEBUG) drawMarker(ctx, 'red');


  const dataURL = canvas.toDataURL('image/jpg');


function render() {
    getRotatedImage(app.image, {degree:}, renderResultImage)

Why does integer division in C# return an integer and not a float?

Might be useful:

double a = 5.0/2.0;   
Console.WriteLine (a);      // 2.5

double b = 5/2;   
Console.WriteLine (b);      // 2

int c = 5/2;   
Console.WriteLine (c);      // 2

double d = 5f/2f;   
Console.WriteLine (d);      // 2.5

How can I force a hard reload in Chrome for Android

I found a solution that works, but it's ugly.

  • Connect the Android device to your PC with a USB cable and open Chrome on your desktop.
  • Right-click anywhere on a page and select "Inspect".
  • Click the three-dot menu and select "Remote devices" under the "More tools" menu:

    enter image description here

  • In the panel that opens, select your device and then the "Inspect" button next to the name of the tab on your phone that needs to be refreshed:

    enter image description here

  • In the window that opens, click the "Network" tab and check the "Disable cache" checkbox:

    enter image description here

  • Reload the page on your phone or using the reload button in the DevTools window.

Note: if your phone doesn't appear in the device list:

  • make sure the USB connection is using File Transfer mode and isn't simply charging
  • try restarting ADB or run adb devices to see if the device is being detected

Can you get the column names from a SqlDataReader?

I use the GetSchemaTable method, which is exposed via the IDataReader interface.

JVM option -Xss - What does it do exactly?

It indeed sets the stack size on a JVM.

You should touch it in either of these two situations:

  • StackOverflowError (the stack size is greater than the limit), increase the value
  • OutOfMemoryError: unable to create new native thread (too many threads, each thread has a large stack), decrease it.

The latter usually comes when your Xss is set too large - then you need to balance it (testing!)


Aside from @Verhás István answer (which I like), I was expecting a one-liner for the question:

${project.reporting.outputDirectory} resolves to target/site in your project.

How to convert a command-line argument to int?

As WhirlWind has pointed out, the recommendations to use atoi aren't really very good. atoi has no way to indicate an error, so you get the same return from atoi("0"); as you do from atoi("abc");. The first is clearly meaningful, but the second is a clear error.

He also recommended strtol, which is perfectly fine, if a little bit clumsy. Another possibility would be to use sscanf, something like:

if (1==sscanf(argv[1], "%d", &temp))
    // successful conversion
    // couldn't convert input

note that strtol does give slightly more detailed results though -- in particular, if you got an argument like 123abc, the sscanf call would simply say it had converted a number (123), whereas strtol would not only tel you it had converted the number, but also a pointer to the a (i.e., the beginning of the part it could not convert to a number).

Since you're using C++, you could also consider using boost::lexical_cast. This is almost as simple to use as atoi, but also provides (roughly) the same level of detail in reporting errors as strtol. The biggest expense is that it can throw exceptions, so to use it your code has to be exception-safe. If you're writing C++, you should do that anyway, but it kind of forces the issue.

How to solve SQL Server Error 1222 i.e Unlock a SQL Server table

To prevent this, make sure every BEGIN TRANSACTION has COMMIT

The following will say successful but will leave uncommitted transactions:


Closing query windows with uncommitted transactions will prompt you to commit your transactions. This will generally resolve the Error 1222 message.