Programs & Examples On #Treemaps

C# try catch continue execution

Or you can encapsulate the looping logic itself in a try catch e.g.

for(int i = function2(); i < 100 /*where 100 is the end or another function call to get the end*/; i = function2()){

    catch { continue; }    



    for(int i = function2(); ; ;) {
        try { i = function2(); return; } 
        finally { /*decide to break or not :P*/continue; } }
} catch { /*failed on first try*/ } finally{ /*afterwardz*/ }

How do you know if Tomcat Server is installed on your PC

You can check in windows services if tomcat is installed it will be listed in windows services.

To check the windows service list of services installed on windows machine use

  WINDOWS KEY + R   and type services.msc

There you can find all the services related with Jasperreport server like Tomcat and MySQL with name starting Jasperreport server Tomcat and MySQL only if these services are installed and its need to be started by selecting the option.Then you can access it through browser using this link :-


default port for tomcat is 8080.

Fatal error: "No Target Architecture" in Visual Studio

Another reason for the error (amongst many others that cropped up when changing the target build of a Win32 project to X64) was not having the C++ 64 bit compilers installed as noted at the top of this page.
Further to philipvr's comment on child headers, (in my case) an explicit include of winnt.h being unnecessary when windows.h was being used.

How can I revert a single file to a previous version?

Let's start with a qualitative description of what we want to do (much of this is said in Ben Straub's answer). We've made some number of commits, five of which changed a given file, and we want to revert the file to one of the previous versions. First of all, git doesn't keep version numbers for individual files. It just tracks content - a commit is essentially a snapshot of the work tree, along with some metadata (e.g. commit message). So, we have to know which commit has the version of the file we want. Once we know that, we'll need to make a new commit reverting the file to that state. (We can't just muck around with history, because we've already pushed this content, and editing history messes with everyone else.)

So let's start with finding the right commit. You can see the commits which have made modifications to given file(s) very easily:

git log path/to/file

If your commit messages aren't good enough, and you need to see what was done to the file in each commit, use the -p/--patch option:

git log -p path/to/file

Or, if you prefer the graphical view of gitk

gitk path/to/file

You can also do this once you've started gitk through the view menu; one of the options for a view is a list of paths to include.

Either way, you'll be able to find the SHA1 (hash) of the commit with the version of the file you want. Now, all you have to do is this:

# get the version of the file from the given commit
git checkout <commit> path/to/file
# and commit this modification
git commit

(The checkout command first reads the file into the index, then copies it into the work tree, so there's no need to use git add to add it to the index in preparation for committing.)

If your file may not have a simple history (e.g. renames and copies), see VonC's excellent comment. git can be directed to search more carefully for such things, at the expense of speed. If you're confident the history's simple, you needn't bother.

Accessing @attribute from SimpleXML

It helped me to convert the result of simplexml_load_file($file) into a JSON Structure and decode it back:

$xml = simplexml_load_file("$token.xml");
$json = json_encode($xml);
$xml_fixed = json_decode($json);

$try1 = $xml->structure->{"@attributes"}['value'];

>> result: SimpleXMLElement Object

$try2 = $xml_fixed->structure->{"@attributes"}['value'];

>> result: stdClass Object
    [key] => value

Location of sqlite database on the device

You can access it using adb shell how-to

Content from above link:

Tutorial : How to access a Android database by using a command line. When your start dealing with a database in your program, it is really important and useful to be able to access it directly, outside your program, to check what the program has just done, and to debug.

And it is important also on Android.

Here is how to do that :

1) Launch the emulator (or connect your real device to your PC ). I usually launch one of my program from Eclipse for this. 2) Launch a command prompt in the android tools directory. 3) type adb shell. This will launch an unix shell on your emulator / connected device. 4) go to the directory where your database is : cd data/data here you have the list of all the applications on your device Go in your application directory ( beware, Unix is case sensitive !! ) cd com.alocaly.LetterGame and descend in your databases directory : cd databases Here you can find all your databases. In my case, there is only one ( now ) : SCORE_DB 5) Launch sqlite on the database you want to check / change : sqlite3 SCORE_DB From here, you can check what tables are present : .tables 6) enter any SQL instruction you want : select * from Score;

This is quite simple, but every time I need it, I don't know where to find it.

Angular 2 Checkbox Two Way Data Binding

Angular: "9.0.0"
Angular CLI: 9.0.1
Node: 13.10.1
OS: linux x64

.html file

<input [(ngModel)]="userConsent" id="userConsent" required type="checkbox"/> " I Accept"

.ts file

userConsent: boolean = false;

How do I install the babel-polyfill library?

First off, the obvious answer that no one has provided, you need to install Babel into your application:

npm install babel --save

(or babel-core if you instead want to require('babel-core/polyfill')).

Aside from that, I have a grunt task to transpile my es6 and jsx as a build step (i.e. I don't want to use babel/register, which is why I am trying to use babel/polyfill directly in the first place), so I'd like to put more emphasis on this part of @ssube's answer:

Make sure you require it at the entry-point to your application, before anything else is called

I ran into some weird issue where I was trying to require babel/polyfill from some shared environment startup file and I got the error the user referenced - I think it might have had something to do with how babel orders imports versus requires but I'm unable to reproduce now. Anyway, moving import 'babel/polyfill' as the first line in both my client and server startup scripts fixed the problem.

Note that if you instead want to use require('babel/polyfill') I would make sure all your other module loader statements are also requires and not use imports - avoid mixing the two. In other words, if you have any import statements in your startup script, make import babel/polyfill the first line in your script rather than require('babel/polyfill').

Any way to limit border length?

Hope this helps:

#mainDiv {_x000D_
  height: 100px;_x000D_
  width: 80px;_x000D_
  position: relative;_x000D_
  border-bottom: 2px solid #f51c40;_x000D_
  background: #3beadc;_x000D_
#borderLeft {_x000D_
  border-left: 2px solid #f51c40;_x000D_
  position: absolute;_x000D_
  top: 50%;_x000D_
  bottom: 0;_x000D_
<div id="mainDiv">_x000D_
  <div id="borderLeft"></div>_x000D_

php - add + 7 days to date format mm dd, YYYY

I would solve this like that. First, I'd create an instance of your given datetime object. Then, I'd create another datetime object which is 7 days later than the initial one. And finally, I'd format it the way you like.

With meringue library, this is quite intuitive and elegant. Here's the code:

(new Future(
    new FromCustomFormat('F j, Y', 'March 3, 2011'),
    new NDays(7)

The result is a string in ISO8601 format. If you like, you can format it anyway you like using the same ISO8601 syntax:

(new ISO8601Formatted(
    new Future(
        new FromCustomFormat('F j, Y', 'March 3, 2011'),
        new NDays(7)
    'F j, Y'

The code above uses meringue library. Here's a quick start, you can take a look if you want.

How to send image to PHP file using Ajax?

Use JavaScript's formData API and set contentType and processData to false

$("form[name='uploader']").on("submit", function(ev) {
  ev.preventDefault(); // Prevent browser default submit.

  var formData = new FormData(this);
    url: "page.php",
    type: "POST",
    data: formData,
    success: function (msg) {
    cache: false,
    contentType: false,
    processData: false

adb connection over tcp not working now

Step 1 . Go to Androidsdk\platform-tools on PC/Laptop

Step 2 :

Connect your device via USB and run:

adb kill-server

then run

adb tcpip 5555

you will see below message...

daemon not running. starting it now on port 5037 * daemon started successfully * restarting in TCP mode port: 5555


Now open new CMD window,

Go to Androidsdk\platform-tools

Now run

adb connect xx.xx.xx.xx:5555 (xx.xx.xx.xx is device IP)

Step4: Disconnect your device from USB and it will work as if connected from your Android studio.

A general tree implementation?

A tree in Python is quite simple. Make a class that has data and a list of children. Each child is an instance of the same class. This is a general n-nary tree.

class Node(object):
    def __init__(self, data): = data
        self.children = []

    def add_child(self, obj):

Then interact:

>>> n = Node(5)
>>> p = Node(6)
>>> q = Node(7)
>>> n.add_child(p)
>>> n.add_child(q)
>>> n.children
[<__main__.Node object at 0x02877FF0>, <__main__.Node object at 0x02877F90>]
>>> for c in n.children:
...   print

This is a very basic skeleton, not abstracted or anything. The actual code will depend on your specific needs - I'm just trying to show that this is very simple in Python.

When to use: Java 8+ interface default method, vs. abstract method

Please think first of open/closed principle. The default methods in interfaces DO VIOLATE it. This is a bad feature in Java. It encourages bad design, bad architecture, low software quality. I would suggest to avoid using default methods completely.

Ask yourself a few questions: Why can't you put your methods to the abstract class? Would you need then more than one abstract class? Then think about what is your class responsible for. Are you sure all methods you are going to put to the single class really fulfill the same purpose? May be you will distinguish several purposes and will then split your class into several classes, for each purpose its own class.

How do I get console input in javascript?

As you mentioned, prompt works for browsers all the way back to IE:

var answer = prompt('question', 'defaultAnswer');

prompt in IE

For Node.js > v7.6, you can use console-read-write, which is a wrapper around the low-level readline module:

const io = require('console-read-write');

async function main() {
  // Simple readline scenario
  io.write('I will echo whatever you write!');

  // Simple question scenario
  io.write(`hello ${await io.ask('Who are you?')}!`);

  // Since you are not blocking the IO, you can go wild with while loops!
  let saidHi = false;
  while (!saidHi) {
    io.write('Say hi or I will repeat...');
    saidHi = await === 'hi';

  io.write('Thanks! Now you may leave.');

// I will echo whatever you write!
// > ok
// ok
// Who are you? someone
// hello someone!
// Say hi or I will repeat...
// > no
// Say hi or I will repeat...
// > ok
// Say hi or I will repeat...
// > hi
// Thanks! Now you may leave.

Disclosure I'm author and maintainer of console-read-write

For SpiderMonkey, simple readline as suggested by @MooGoo and @Zaz.

Understanding the difference between Object.create() and new SomeFunction()

function Test(){
    this.prop1 = 'prop1';
    this.prop2 = 'prop2';
    this.func1 = function(){
        return this.prop1 + this.prop2;

Test.prototype.protoProp1 = 'protoProp1';
Test.prototype.protoProp2 = 'protoProp2';
var newKeywordTest = new Test();
var objectCreateTest = Object.create(Test.prototype);

/* Object.create   */
console.log(objectCreateTest.prop1); // undefined
console.log(objectCreateTest.protoProp1); // protoProp1 
console.log(objectCreateTest.__proto__.protoProp1); // protoProp1

/* new    */
console.log(newKeywordTest.prop1); // prop1
console.log(newKeywordTest.__proto__.protoProp1); // protoProp1


1) with new keyword there are two things to note;

a) function is used as a constructor

b) function.prototype object is passed to the __proto__ property ... or where __proto__ is not supported, it is the second place where the new object looks to find properties

2) with Object.create(obj.prototype) you are constructing an object (obj.prototype) and passing it to the intended object ..with the difference that now new object's __proto__ is also pointing to obj.prototype (please ref ans by xj9 for that)

isset PHP isset($_GET['something']) ? $_GET['something'] : ''

That's called a ternary operator and it's mainly used in place of an if-else statement.

In the example you gave it can be used to retrieve a value from an array given isset returns true

isset($_GET['something']) ? $_GET['something'] : ''

is equivalent to

if (isset($_GET['something'])) {
} else {

Of course it's not much use unless you assign it to something, and possibly even assign a default value for a user submitted value.

$username = isset($_GET['username']) ? $_GET['username'] : 'anonymous'

Link to download apache http server for 64bit windows.

you can find multiple options listed at

ApacheHaus Apache Lounge BitNami WAMP Stack WampServer XAMPP

Is #pragma once a safe include guard?

Additional note to the people thinking that an automatic one-time-only inclusion of header files is always desired: I build code generators using double or multiple inclusion of header files since decades. Especially for generation of protocol library stubs I find it very comfortable to have a extremely portable and powerful code generator with no additional tools and languages. I'm not the only developer using this scheme as this blogs X-Macros show. This wouldn't be possible to do without the missing automatic guarding.

Request exceeded the limit of 10 internal redirects due to probable configuration error

//Just add 

RewriteBase /
RewriteEngine On

//and you are done....

//so it should be 

RewriteEngine On
RewriteBase /
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^ index.php [QSA,L]

Remove privileges from MySQL database

As a side note, the reason revoke usage on *.* from 'phpmyadmin'@'localhost'; does not work is quite simple : There is no grant called USAGE.

The actual named grants are in the MySQL Documentation

The grant USAGE is a logical grant. How? 'phpmyadmin'@'localhost' has an entry in mysql.user where user='phpmyadmin' and host='localhost'. Any row in mysql.user semantically means USAGE. Running DROP USER 'phpmyadmin'@'localhost'; should work just fine. Under the hood, it's really doing this:

DELETE FROM mysql.user WHERE user='phpmyadmin' and host='localhost';
DELETE FROM mysql.db   WHERE user='phpmyadmin' and host='localhost';

Therefore, the removal of a row from mysql.user constitutes running REVOKE USAGE, even though REVOKE USAGE cannot literally be executed.

How to add DOM element script to head section?

If injecting multiple script tags in the head like this with mix of local and remote script files a situation may arise where the local scripts that are dependent on external scripts (such as loading jQuery from googleapis) will have errors because the external scripts may not be loaded before the local ones are.

So something like this would have a problem: ("jQuery is not defined" in jquery.some-plugin.js).

var head = document.getElementsByTagName('head')[0];

var script = document.createElement('script');
script.type = 'text/javascript';
script.src = "";

var script = document.createElement('script');
script.type = 'text/javascript';
script.src = "/jquery.some-plugin.js";

Of course this situation is what the .onload() is for, but if multiple scripts are being loaded that can be cumbersome.

As a resolution to this situation, I put together this function that will keep a queue of scripts to be loaded, loading each subsequent item after the previous finishes, and returns a Promise that resolves when the script (or the last script in the queue if no parameter) is done loading.

load_script = function(src) {
    // Initialize scripts queue
    if( load_script.scripts === undefined ) {
        load_script.scripts = [];
        load_script.index = -1;
        load_script.loading = false; = function() {
            if( load_script.loading ) return;

            // Load the next queue item
            load_script.loading = true;
            var item = load_script.scripts[++load_script.index];
            var head = document.getElementsByTagName('head')[0];
            var script = document.createElement('script');
            script.type = 'text/javascript';
            script.src = item.src;
            // When complete, start next item in queue and resolve this item's promise
            script.onload = () => {
                load_script.loading = false;
                if( load_script.index < load_script.scripts.length - 1 );

    // Adding a script to the queue
    if( src ) {
        // Check if already added
        for(var i=0; i < load_script.scripts.length; i++) {
            if( load_script.scripts[i].src == src ) return load_script.scripts[i].promise;
        // Add to the queue
        var item = { src: src };
        item.promise = new Promise(resolve => {item.resolve = resolve;});

    // Return the promise of the last queue item
    return load_script.scripts[ load_script.scripts.length - 1 ].promise;

With this adding scripts in order ensuring the previous are done before staring the next can be done like...


Or load the script and use the return Promise to do work when it's complete...

.then(function() {
    /* some-script.js is done loading */

ConnectivityManager getNetworkInfo(int) deprecated

It is good to check whether your network is connected to Internet:

fun isNetworkAvailable(context: Context): Boolean {
    try {
        val cm = context.getSystemService(Context.CONNECTIVITY_SERVICE) as ConnectivityManager
        return if (Build.VERSION.SDK_INT > 22) {
            val an = cm.activeNetwork ?: return false
            val capabilities = cm.getNetworkCapabilities(an) ?: return false
        } else {
            val a = cm.activeNetworkInfo ?: return false
            a.isConnected && (a.type == ConnectivityManager.TYPE_WIFI || a.type == ConnectivityManager.TYPE_MOBILE)
    } catch (e: Exception) {
    return false

Remove scrollbars from textarea

Give a class for eg: scroll to the textarea tag. And in the css add this property -

.scroll::-webkit-scrollbar {
   display: none;
<textarea class='scroll'></textarea>

It worked for without missing the scroll part

CSS3 Fade Effect

It's possible, use the structure below:



Where the <li> contains an <a> anchor tag that contains a span as shown above. Then insert the following css:

  • LI get position: relative;
  • Give <a> tag a height, width
  • Set <span> width & height to 100%, so that both <a> and <span> have same dimensions
  • Both <a> and <span> get position: relative;.
  • Assign the same background image to each element
  • <a> tag will have the 'OFF' background-position, and the <span> will have the 'ON' background-poisiton.
  • For 'OFF' state use opacity 0 for <span>
  • For 'ON' :hover state use opacity 1 for <span>
  • Set the -webkit or -moz transition on the <span> element

You'll have the ability to use the transition effect while still defaulting to the old background-position swap. Don't forget to insert IE alpha filter.

How can I see the specific value of the sql_mode?

It's only blank for you because you have not set the sql_mode. If you set it, then that query will show you the details:

mysql> SELECT @@sql_mode;
| @@sql_mode |
|            |
1 row in set (0.00 sec)

mysql> set sql_mode=ORACLE;
Query OK, 0 rows affected (0.00 sec)

mysql> SELECT @@sql_mode;
| @@sql_mode                                                                                                           |
1 row in set (0.00 sec)

How to downgrade from Internet Explorer 11 to Internet Explorer 10?

  1. Save and close all Internet Explorer windows and then, run Windows Task Manager to end the running processes in background.
  2. Go to Control Panel.
  3. Click Programs and choose the View installed updates instead.
  4. Locate the following Windows Internet Explorer 11 or you can type "Internet Explorer" for a quick search.
  5. Choose the Yes option from the following "Uninstall an update".
  6. Please wait while Windows Internet Explorer 10 is being restored and reconfigured automatically.
  7. Follow the Microsoft Windows wizard to restart your system.

Note: You can do it for as many earlier versions you want, i.e. IE9, IE8 and so on.

How to change the default message of the required field in the popover of form-control in bootstrap?

You can use setCustomValidity function when oninvalid event occurs.

Like below:-

<input class="form-control" type="email" required="" 
    placeholder="username" oninvalid="this.setCustomValidity('Please Enter valid email')">


To clear the message once you start entering use oninput="setCustomValidity('') attribute to clear the message.

<input class="form-control" type="email"  required="" placeholder="username"
 oninvalid="this.setCustomValidity('Please Enter valid email')"

Convert string to decimal number with 2 decimal places in Java

Float.parseFloat() is the problem as it returns a new float.

Returns a new float initialized to the value represented by the specified String, as performed by the valueOf method of class Float.

You are formatting just for the purpose of display . It doesn't mean the float will be represented by the same format internally .

You can use java.lang.BigDecimal.

I am not sure why are you using parseFloat() twice. If you want to display the float in a certain format then just format it and display it.

Float litersOfPetrol=Float.parseFloat(stringLitersOfPetrol);
DecimalFormat df = new DecimalFormat("0.00");
System.out.println("liters of petrol before putting in editor"+df.format(litersOfPetrol));

How to rename with prefix/suffix?

Bulk rename files bash script

# USAGE EXAMPLE: cd PHOTOS; /home/Desktop/ 2016_
# VERSION: 2016.03.05.
# COPYRIGHT: Harkály Gergo | mangoRDI ( 

# check isset INITNUMBER argument, if not, set 1 | INITNUMBER is the first number after renaming
if [ -z "$2" ]
    then i=1;

# counts the files to set leading zeros before number | max 1000 files
count=$(ls -l * | wc -l)
if [ $count -lt 10 ]
    then zeros=1;
    if [ $count -lt 100 ]
        then zeros=2;

# rename script
for file in *
    mv $file $1_$(printf %0"$zeros"d.%s ${i%.*} ${file##*.})
    let i="$i+1"

Kubernetes service external ip pending

It looks like you are using a custom Kubernetes Cluster (using minikube, kubeadm or the like). In this case, there is no LoadBalancer integrated (unlike AWS or Google Cloud). With this default setup, you can only use NodePort or an Ingress Controller.

With the Ingress Controller you can setup a domain name which maps to your pod; you don't need to give your Service the LoadBalancer type if you use an Ingress Controller.

This declaration has no storage class or type specifier in C++

Calling m.check(side), meaning you are running actual code, but you can't run code outside main() - you can only define variables. In C++, code can only appear inside function bodies or in variable initializes.

How do I fix the "You don't have write permissions into the /usr/bin directory" error when installing Rails?

I'd suggest using RVM it allows you have multiple versions of Ruby/Rails installed with gem profiles and basically keep all your gems contained from one another. You may want to check out a similar post How can I install Ruby on Rails 3 on OSX

Rownum in postgresql

Postgresql does not have an equivalent of Oracle's ROWNUM. In many cases you can achieve the same result by using LIMIT and OFFSET in your query.

Selenium IDE - Command to wait for 5 seconds

This will wait until your link has appeared, and then you can click it.

Command: waitForElementPresent Target: link=do something Value:

How to create a custom scrollbar on a div (Facebook style)

If you're looking for a Facebook like scroll bar, then I'd highly recommend you take a look at this one:

Encoding as Base64 in Java

Here are my two cents... Java 8 does contain its own implementation of Base64. However, I found one slightly disturbing difference. To illustrate, I will provide a code example:

My codec wrapper:

public interface MyCodec
  static String apacheDecode(String encodedStr)
    return new String(Base64.decodeBase64(encodedStr), Charset.forName("UTF-8"));

  static String apacheEncode(String decodedStr)
    byte[] decodedByteArr = decodedStr.getBytes(Charset.forName("UTF-8"));
    return Base64.encodeBase64String(decodedByteArr);

  static String javaDecode(String encodedStr)
    return new String(java.util.Base64.getDecoder().decode(encodedStr), Charset.forName("UTF-8"));

  static String javaEncode(String decodedStr)
    byte[] decodedByteArr = decodedStr.getBytes(Charset.forName("UTF-8"));
    return java.util.Base64.getEncoder().encodeToString(decodedByteArr);

Test Class:

public class CodecDemo
  public static void main(String[] args)
    String decodedText = "Hello World!";

    String encodedApacheText = MyCodec.apacheEncode(decodedText);
    String encodedJavaText = MyCodec.javaEncode(decodedText);

    System.out.println("Apache encoded text: " + MyCodec.apacheEncode(encodedApacheText));
    System.out.println("Java encoded text: " + MyCodec.javaEncode(encodedJavaText));

    System.out.println("Encoded results equal: " + encodedApacheText.equals(encodedJavaText));

    System.out.println("Apache decode Java: " + MyCodec.apacheDecode(encodedJavaText));
    System.out.println("Java decode Java: " + MyCodec.javaDecode(encodedJavaText));

    System.out.println("Apache decode Apache: " + MyCodec.apacheDecode(encodedApacheText));
    System.out.println("Java decode Apache: " + MyCodec.javaDecode(encodedApacheText));


Apache encoded text: U0dWc2JHOGdWMjl5YkdRaA0K

Java encoded text: U0dWc2JHOGdWMjl5YkdRaA==
Encoded results equal: false
Apache decode Java: Hello World!
Java decode Java: Hello World!
Apache decode Apache: Hello World!
Exception in thread "main" java.lang.IllegalArgumentException: Illegal base64 character d
    at java.util.Base64$Decoder.decode0(
    at java.util.Base64$Decoder.decode(
    at java.util.Base64$Decoder.decode(

Notice that the Apache encoded text contain additional line breaks (white spaces) at the end. Therefore, in order for my codec to yield the same result regardless of Base64 implementation, I had to call trim() on the Apache encoded text. In my case, I simply added the aforementioned method call to the my codec's apacheDecode() as follows:

return Base64.encodeBase64String(decodedByteArr).trim();

Once this change was made, the results are what I expected to begin with:

Apache encoded text: U0dWc2JHOGdWMjl5YkdRaA==
Java encoded text: U0dWc2JHOGdWMjl5YkdRaA==
Encoded results equal: true
Apache decode Java: Hello World!
Java decode Java: Hello World!
Apache decode Apache: Hello World!
Java decode Apache: Hello World!

CONCLUSION: If you want to switch from Apache Base64 to Java, you must:

  1. Decode encoded text with your Apache decoder.
  2. Encode resulting (plain) text with Java.

If you switch without following these steps, most likely you will run into problems. That is how I made this discovery.

What is difference between MVC, MVP & MVVM design pattern in terms of coding c#

Some basic differences can be written in short:


Traditional MVC is where there is a

  1. Model: Acts as the model for data
  2. View : Deals with the view to the user which can be the UI
  3. Controller: Controls the interaction between Model and View, where view calls the controller to update model. View can call multiple controllers if needed.


Similar to traditional MVC but Controller is replaced by Presenter. But the Presenter, unlike Controller is responsible for changing the view as well. The view usually does not call the presenter.


The difference here is the presence of View Model. It is kind of an implementation of Observer Design Pattern, where changes in the model are represented in the view as well, by the VM. Eg: If a slider is changed, not only the model is updated but the data which may be a text, that is displayed in the view is updated as well. So there is a two-way data binding.

How to control font sizes in pgf/tikz graphics in latex?

You can also use:


The huge advantage of the anyfontsize package over scalefnt is that one does not need to enclose the entire {tikzpicture} with a \scalefont environment.

Just adding \usepackage{anyfontsize} to the preamble is all that is required for the font scaling magic to happen.

How to parse date string to Date?

I had this issue, and I set the Locale to US, then it work.

static DateFormat visitTimeFormat = new SimpleDateFormat("EEE MMM dd HH:mm:ss zzz yyyy",Locale.US);

for String "Sun Jul 08 00:06:30 UTC 2012"

#1062 - Duplicate entry for key 'PRIMARY'

Use SHOW CREATE TABLE your-table-name to see what column is your primary key.

curl usage to get header

You need to add the -i flag to the first command, to include the HTTP header in the output. This is required to print headers.

curl -X HEAD -i

More here:

How do I center an SVG in a div?

None of these answers worked for me. This is how I did it.

position: relative;
left: 50%;
-webkit-transform: translateX(-50%);
-ms-transform: translateX(-50%);
transform: translateX(-50%);

Algorithm to compare two images

If you're willing to consider a different approach altogether to detecting illegal copies of your images, you could consider watermarking. (from 1.4)

...inserts copyright information into the digital object without the loss of quality. Whenever the copyright of a digital object is in question, this information is extracted to identify the rightful owner. It is also possible to encode the identity of the original buyer along with the identity of the copyright holder, which allows tracing of any unauthorized copies.

While it's also a complex field, there are techniques that allow the watermark information to persist through gross image alteration: (from 1.9)

... any signal transform of reasonable strength cannot remove the watermark. Hence a pirate willing to remove the watermark will not succeed unless they debase the document too much to be of commercial interest.

of course, the faq calls implementing this approach: "...very challenging" but if you succeed with it, you get a high confidence of whether the image is a copy or not, rather than a percentage likelihood.

How do I get indices of N maximum values in a NumPy array?

When top_k<<axis_length,it better than argsort.

import numpy as np

def get_sorted_top_k(array, top_k=1, axis=-1, reverse=False):
    if reverse:
        axis_length = array.shape[axis]
        partition_index = np.take(np.argpartition(array, kth=-top_k, axis=axis),
                                  range(axis_length - top_k, axis_length), axis)
        partition_index = np.take(np.argpartition(array, kth=top_k, axis=axis), range(0, top_k), axis)
    top_scores = np.take_along_axis(array, partition_index, axis)
    # resort partition
    sorted_index = np.argsort(top_scores, axis=axis)
    if reverse:
        sorted_index = np.flip(sorted_index, axis=axis)
    top_sorted_scores = np.take_along_axis(top_scores, sorted_index, axis)
    top_sorted_indexes = np.take_along_axis(partition_index, sorted_index, axis)
    return top_sorted_scores, top_sorted_indexes

if __name__ == "__main__":
    import time
    from sklearn.metrics.pairwise import cosine_similarity

    x = np.random.rand(10, 128)
    y = np.random.rand(1000000, 128)
    z = cosine_similarity(x, y)
    start_time = time.time()
    sorted_index_1 = get_sorted_top_k(z, top_k=3, axis=1, reverse=True)[1]
    print(time.time() - start_time)

Fast ceiling of an integer division in C / C++

For positive numbers

unsigned int x, y, q;

To round up ...

q = (x + y - 1) / y;

or (avoiding overflow in x+y)

q = 1 + ((x - 1) / y); // if x != 0

MySQL delete multiple rows in one query conditions unique to each row

A slight extension to the answer given, so, hopefully useful to the asker and anyone else looking.

You can also SELECT the values you want to delete. But watch out for the Error 1093 - You can't specify the target table for update in FROM clause.

    (branchID, action) IN (
        GROUP BY
            COUNT(*) > 10000
        ) a

I wanted to delete all history records where the number of history records for a single action/branch exceed 10,000. And thanks to this question and chosen answer, I can.

Hope this is of use.


How to set <Text> text to upper case in react native

iOS textTransform support has been added to react-native in 0.56 version. Android textTransform support has been added in 0.59 version. It accepts one of these options:

  • none
  • uppercase
  • lowercase
  • capitalize

The actual iOS commit, Android commit and documentation


  <Text style={{ textTransform: 'uppercase'}}>
    This text should be uppercased.
  <Text style={{ textTransform: 'capitalize'}}>
    Mixed:{' '}
    <Text style={{ textTransform: 'lowercase'}}>
      lowercase{' '}

JavaFX FXML controller - constructor vs initialize method

In Addition to the above answers, there probably should be noted that there is a legacy way to implement the initialization. There is an interface called Initializable from the fxml library.

import javafx.fxml.Initializable;

class MyController implements Initializable {
    @FXML private TableView<MyModel> tableView;

    public void initialize(URL location, ResourceBundle resources) {


location - The location used to resolve relative paths for the root object, or null if the location is not known.
resources - The resources used to localize the root object, or null if the root object was not localized. 

And the note of the docs why the simple way of using @FXML public void initialize() works:

NOTE This interface has been superseded by automatic injection of location and resources properties into the controller. FXMLLoader will now automatically call any suitably annotated no-arg initialize() method defined by the controller. It is recommended that the injection approach be used whenever possible.

Pylint, PyChecker or PyFlakes?

Well, I am a bit curious, so I just tested the three myself right after asking the question ;-)

Ok, this is not a very serious review, but here is what I can say:

I tried the tools with the default settings (it's important because you can pretty much choose your check rules) on the following script:

# by Daniel Rosengren modified by e-satis

import sys, time
stdout = sys.stdout


class Iterator(object) :

    def __init__(self):

        print 'Rendering...'
        for y in xrange(-39, 39):
            for x in xrange(-39, 39):
                if self.mandelbrot(x/40.0, y/40.0) :
                    stdout.write(' ')

    def mandelbrot(self, x, y):
        cr = y - 0.5
        ci = x
        zi = 0.0
        zr = 0.0

        for i in xrange(MAX_ITERATIONS) :
            temp = zr * zi
            zr2 = zr * zr
            zi2 = zi * zi
            zr = zr2 - zi2 + cr
            zi = temp + temp + ci

            if zi2 + zr2 > BAILOUT:
                return i

        return 0

t = time.time()
print '\nPython Elapsed %.02f' % (time.time() - t)

As a result:

  • PyChecker is troublesome because it compiles the module to analyze it. If you don't want your code to run (e.g, it performs a SQL query), that's bad.
  • PyFlakes is supposed to be light. Indeed, it decided that the code was perfect. I am looking for something quite severe so I don't think I'll go for it.
  • PyLint has been very talkative and rated the code 3/10 (OMG, I'm a dirty coder !).

Strong points of PyLint:

  • Very descriptive and accurate report.
  • Detect some code smells. Here it told me to drop my class to write something with functions because the OO approach was useless in this specific case. Something I knew, but never expected a computer to tell me :-p
  • The fully corrected code run faster (no class, no reference binding...).
  • Made by a French team. OK, it's not a plus for everybody, but I like it ;-)

Cons of Pylint:

  • Some rules are really strict. I know that you can change it and that the default is to match PEP8, but is it such a crime to write 'for x in seq'? Apparently yes because you can't write a variable name with less than 3 letters. I will change that.
  • Very very talkative. Be ready to use your eyes.

Corrected script (with lazy doc strings and variable names):

# by Daniel Rosengren, modified by e-satis
Module doctring

import time
from sys import stdout


def mandelbrot(dim_1, dim_2):
    function doc string
    cr1 = dim_1 - 0.5
    ci1 = dim_2
    zi1 = 0.0
    zr1 = 0.0

    for i in xrange(MAX_ITERATIONS) :
        temp = zr1 * zi1
        zr2 = zr1 * zr1
        zi2 = zi1 * zi1
        zr1 = zr2 - zi2 + cr1
        zi1 = temp + temp + ci1

        if zi2 + zr2 > BAILOUT:
            return i

    return 0

def execute() :
    func doc string
    print 'Rendering...'
    for dim_1 in xrange(-39, 39):
        for dim_2 in xrange(-39, 39):
            if mandelbrot(dim_1/40.0, dim_2/40.0) :
                stdout.write(' ')

START_TIME = time.time()
print '\nPython Elapsed %.02f' % (time.time() - START_TIME)

Thanks to Rudiger Wolf, I discovered pep8 that does exactly what its name suggests: matching PEP8. It has found several syntax no-nos that Pylint did not. But Pylint found stuff that was not specifically linked to PEP8 but interesting. Both tools are interesting and complementary.

Eventually I will use both since there are really easy to install (via packages or setuptools) and the output text is so easy to chain.

To give you a little idea of their output:


./ E401 multiple imports on one line
./ E302 expected 2 blank lines, found 1
./ E203 whitespace before ':'
./ E501 line too long (108 characters)
./ W291 trailing whitespace
./ E301 expected 1 blank line, found 3


************* Module python_mandelbrot
C: 15: Line too long (108/80)
C: 61: Line too long (85/80)
C:  1: Missing docstring
C:  5: Invalid name "stdout" (should match (([A-Z_][A-Z0-9_]*)|(__.*__))$)
C: 10:Iterator: Missing docstring
C: 15:Iterator.__init__: Invalid name "y" (should match [a-z_][a-z0-9_]{2,30}$)
C: 17:Iterator.__init__: Invalid name "x" (should match [a-z_][a-z0-9_]{2,30}$)

[...] and a very long report with useful stats like :


|                         |now   |previous |difference |
|nb duplicated lines      |0     |0        |=          |
|percent duplicated lines |0.000 |0.000    |=          |

How to measure time elapsed on Javascript?

var seconds = 0;
setInterval(function () {
}, 1000);

There you go, now you have a variable counting seconds elapsed. Since I don't know the context, you'll have to decide whether you want to attach that variable to an object or make it global.

Set interval is simply a function that takes a function as it's first parameter and a number of milliseconds to repeat the function as it's second parameter.

You could also solve this by saving and comparing times.

EDIT: This answer will provide very inconsistent results due to things such as the event loop and the way browsers may choose to pause or delay processing when a page is in a background tab. I strongly recommend using the accepted answer.

Are there any worse sorting algorithms than Bogosort (a.k.a Monkey Sort)?

Recursive Bogosort (probably still O(n!){
if (list not sorted)
list1 = first half of list.
list 2 = second half of list.
Recursive bogosort (list1);
Recursive bogosort (list2);
list = list1 + list2
while(list not sorted)

Updating address bar with new URL without hash or reloading the page

You can now do this in most "modern" browsers!

Here is the original article I read (posted July 10, 2010): HTML5: Changing the browser-URL without refreshing page.

For a more in-depth look into pushState/replaceState/popstate (aka the HTML5 History API) see the MDN docs.

TL;DR, you can do this:

window.history.pushState("object or string", "Title", "/new-url");

See my answer to Modify the URL without reloading the page for a basic how-to.

The type cannot be resolved. It is indirectly referenced from required .class files

I was also facing same issue. I had Jdk1.7.0.79. Then I updated it with Jdk8.0.120. Then the problem solved. After successful completion of upgraded jdk. Go to project->clean. It will rebuild the project and all red alert will be eliminated.

How to compare two dates to find time difference in SQL Server 2005, date manipulation

Cast the result as TIME and the result will be in time format for duration of the interval.

select CAST(job_end - job_start) AS TIME(0)) from tableA

How to install Maven 3 on Ubuntu 18.04/17.04/16.10/16.04 LTS/15.10/15.04/14.10/14.04 LTS/13.10/13.04 by using apt-get?

It's best to use miske's answer.

Properly installing natecarlson's repository

If you really want to use natecarlson's repository, the instructions just below can do any of the following:

  1. set it up from scratch
  2. repair it if apt-get update gives a 404 error after add-apt-repository
  3. repair it if apt-get update gives a NO_PUBKEY error after manually adding it to /etc/apt/sources.list

Open a terminal and run the following:

sudo -i

Enter your password if necessary, then paste the following into the terminal:

export GOOD_RELEASE='precise'
export BAD_RELEASE="`lsb_release -cs`"
cd /etc/apt
sed -i '/natecarlson\/maven3/d' sources.list
cd sources.list.d
rm -f natecarlson-maven3-*.list*
apt-add-repository -y ppa:natecarlson/maven3
mv natecarlson-maven3-${BAD_RELEASE}.list natecarlson-maven3-${GOOD_RELEASE}.list
sed -i "s/${BAD_RELEASE}/${GOOD_RELEASE}/" natecarlson-maven3-${GOOD_RELEASE}.list
apt-get update
echo Done!

Removing natecarlson's repository

If you installed natecarlson's repository (either using add-apt-repository or manually added to /etc/apt/sources.list) and you don't want it anymore, open a terminal and run the following:

sudo -i

Enter your password if necessary, then paste the following into the terminal:

cd /etc/apt
sed -i '/natecarlson\/maven3/d' sources.list
cd sources.list.d
rm -f natecarlson-maven3-*.list*
apt-get update
echo Done!

How To Create Table with Identity Column

[id] [int] IDENTITY(1,1) NOT NULL,

of course since you're creating the table in SQL Server Management Studio you could use the table designer to set the Identity Specification.

enter image description here

How to write and read java serialized objects into a file

Simple program to write objects to file and read objects from file.

package program;_x000D_
public class TempList {_x000D_
  public static void main(String[] args) throws Exception {_x000D_
    Counter counter = new Counter(10);_x000D_
    File f = new File("MyFile.txt");_x000D_
    FileOutputStream fos = new FileOutputStream(f);_x000D_
    ObjectOutputStream oos = new ObjectOutputStream(fos);_x000D_
    FileInputStream fis = new FileInputStream(f);_x000D_
    ObjectInputStream ois = new ObjectInputStream(fis);_x000D_
    Counter newCounter = (Counter) ois.readObject();_x000D_
class Counter implements Serializable {_x000D_
  private static final long serialVersionUID = -628789568975888036 L;_x000D_
  int count;_x000D_
  Counter(int count) {_x000D_
    this.count = count;_x000D_

After running the program the output in your console window will be 10 and you can find the file inside Test folder by clicking on the icon show in below image.

enter image description here

less than 10 add 0 to number

I was bored and playing around JSPerf trying to beat the currently selected answer prepending a zero no matter what and using slice(-2). It's a clever approach but the performance gets a lot worse as the string gets longer.

For numbers zero to ten (one and two character strings) I was able to beat by about ten percent, and the fastest approach was much better when dealing with longer strings by using charAt so it doesn't have to traverse the whole string.

This follow is not quit as simple as slice(-2) but is 86%-89% faster when used across mostly 3 digit numbers (3 character strings).

var prepended = ( 1 === string.length && string.charAt( 0 ) !== "0" ) ? '0' + string : string;

how to get the value of css style using jquery

You code is correct. replace items with .items as below

  var n = $(".items").css("left");
  if(n == -900){
    $(".items span").fadeOut("slow");

The iOS Simulator deployment targets is set to 7.0, but the range of supported deployment target version for this platform is 8.0 to 12.1

The problem is in your pod files deployment target iOS Version not in your project deployment target iOS Version, so you need to change the deployment iOS version for your pods as well to anything higher than 8.0 to do so open your project workspace and do this:

1- Click on pods.

2- Select each project and target and click on build settings.

3- Under Deployment section change the iOS Deployment Target version to anything more than 8.0 (better to try the same project version).

4- Repeat this for every other project in your pods then run the app.

see the photo for details enter image description here

PHP Date Format to Month Name and Year

if you want same string output then try below else use without double quotes for proper output

$str = '20130814';
  echo date('"F Y"', strtotime($str));

//output  : "August 2013" 

How to redirect verbose garbage collection output to a file?

If in addition you want to pipe the output to a separate file, you can do:

On a Sun JVM:

-Xloggc:C:\whereever\jvm.log -verbose:gc -XX:+PrintGCDateStamps



Setting initial values on load with Select2 with Ajax

you can use the following

$(element).select2("data",[ { id:, text: "???? ???? ??????" },
    { id: 2, text: "???? ???? ????" }]);

Using `date` command to get previous, current and next month

the main problem occur when you don't have date --date option available and you don't have permission to install it, then try below -

Previous month
#cal -3|awk 'NR==1{print toupper(substr($1,1,3))"-"$2}'
Current month
#cal -3|awk 'NR==1{print toupper(substr($3,1,3))"-"$4}'
Next month
#cal -3|awk 'NR==1{print toupper(substr($5,1,3))"-"$6}'

Android Call an method from another class

And, if you don't want to instantiate Class2, declare UpdateEmployee as static and call it like this:


However, you'll normally want to do what @parag said.

How do I split a string with multiple separators in JavaScript?

I ran into this question wile looking for a replacement for the C# string.Split() function which splits a string using the characters in its argument.

In JavaScript you can do the same using map an reduce to iterate over the splitting characters and the intermediate values:

let splitters = [",", ":", ";"]; // or ",:;".split("");
let start= "a,b;c:d";
let values = splitters.reduce((old, c) => => v.split(c)).flat(), [start]);
// values is ["a", "b", "c", "d"]

flat() is used to flatten the intermediate results so each iteration works on a list of strings without nested arrays. Each iteration applies split to all of the values in old and then returns the list of intermediate results to be split by the next value in splitters. reduce() is initialized with an array containing the initial string value.

Can you force a React component to rerender without calling setState?

Another way is calling setState, AND preserve state:


What is the easiest/best/most correct way to iterate through the characters of a string in Java?

Note most of the other techniques described here break down if you're dealing with characters outside of the BMP (Unicode Basic Multilingual Plane), i.e. code points that are outside of the u0000-uFFFF range. This will only happen rarely, since the code points outside this are mostly assigned to dead languages. But there are some useful characters outside this, for example some code points used for mathematical notation, and some used to encode proper names in Chinese.

In that case your code will be:

String str = "....";
int offset = 0, strLen = str.length();
while (offset < strLen) {
  int curChar = str.codePointAt(offset);
  offset += Character.charCount(curChar);
  // do something with curChar

The Character.charCount(int) method requires Java 5+.


Extracting time from POSIXct

Many solutions have been provided, but I have not seen this one, which uses package chron:

hours = times(strftime(times, format="%T"))

(sorry, I am not entitled to post an image, you'll have to plot it yourself)

SSL InsecurePlatform error when using Requests package

All of the solutions given here haven't helped (I'm constrained to python 2.6.6). I've found the answer in a simple switch to pass to pip:

$ sudo pip install --trusted-host <module_name>

This tells pip that it's OK to grab the module from

For me, the issue is my company's proxy behind it's firewall that makes it look like a malicious client to some servers. Hooray security.

Update: See @Alex 's answer for changes in the PyPi domains, and additional --trusted-host options that can be added. (I'd copy/paste here, but his answer, so +1 him)

Android ADB device offline, can't issue commands

None of these answers worked for me, tried Wireless too. I noticed adb.exe was constantly running in my system processes. Right clicked on them and found adb was running automatically from an installed app (Droid Explorer in my case). Once I uninstalled the app that was automatically starting ADB, i could kill the process and see that adb was no longer running on it's own. Ran the updated adb from platform-tools and good to go! Hope this helps someone.

Why Is Subtracting These Two Times (in 1927) Giving A Strange Result?

When incrementing time you should convert back to UTC and then add or subtract. Use the local time only for display.

This way you will be able to walk through any periods where hours or minutes happen twice.

If you converted to UTC, add each second, and convert to local time for display. You would go through 11:54:08 p.m. LMT - 11:59:59 p.m. LMT and then 11:54:08 p.m. CST - 11:59:59 p.m. CST.

How do I plot in real-time in a while loop using matplotlib?

Here is a version that I got to work on my system.

import matplotlib.pyplot as plt
from drawnow import drawnow
import numpy as np

def makeFig():
    plt.scatter(xList,yList) # I think you meant this

plt.ion() # enable interactivity
fig=plt.figure() # make a figure


for i in np.arange(50):
    #makeFig()      The drawnow(makeFig) command can be replaced
    #plt.draw()     with makeFig(); plt.draw()

The drawnow(makeFig) line can be replaced with a makeFig(); plt.draw() sequence and it still works OK.

Random character generator with a range of (A..Z, 0..9) and punctuation

  1. Pick a random number between [0, x), where x is the number of different symbols. Hopefully the choice is uniformly chosen and not predictable :-)

  2. Now choose the symbol representing x.

  3. Profit!

I would start reading up Pseudorandomness and then some common Pseudo-random number generators. Of course, your language hopefully already has a suitable "random" function :-)

Convert java.util.Date to java.time.LocalDate

first, it's easy to convert a Date to an Instant

Instant timestamp = new Date().toInstant(); 

Then, you can convert the Instant to any date api in jdk 8 using ofInstant() method:

LocalDateTime date = LocalDateTime.ofInstant(timestamp, ZoneId.systemDefault()); 

How to use RANK() in SQL Server

Select T.Tamil, T.English, T.Maths, T.Total, Dense_Rank()Over(Order by T.Total Desc) as Std_Rank From (select Tamil,English,Maths,(Tamil+English+Maths) as Total From Student) as T

enter image description here

clearing a char array c

An array in C is just a memory location, so indeed, your my_custom_data[0] = '\0'; assignment simply sets the first element to zero and leaves the other elements intact.

If you want to clear all the elements of the array, you'll have to visit each element. That is what memset is for:

memset(&arr[0], 0, sizeof(arr));

This is generally the fastest way to take care of this. If you can use C++, consider std::fill instead:

char *begin = &arr;
char *end = begin + sizeof(arr);
std::fill(begin, end, 0);

grant remote access of MySQL database from any IP address

Edit File:


Append below code in file.

[mysqld] bind-address =

Create user for remote access.

$ mysql -u root -p      
mysql> GRANT ALL ON *.* to snippetbucketdotcom@'%' IDENTIFIED BY 'tejastank';   
mysql> exit

All linux server works,

For MSWin c:\ Find insatallation location \ file path

How can I get my Twitter Bootstrap buttons to right align?

Insert pull-right into the class attribute and let bootstrap arrange the buttons.

For Bootstrap 2.3, see: > Helper classes > .pull-right.

For Bootstrap 3, see: > Helper classes.

For Bootstrap 4, see:

The pull-right command was removed and replaced with float-right or in general to float-{sm,md,lg,xl}-{left,right,none}

More elegant "ps aux | grep -v grep"

You could use preg_split instead of explode and split on [ ]+ (one or more spaces). But I think in this case you could go with preg_match_all and capturing:

preg_match_all('/[ ]php[ ]+\S+[ ]+(\S+)/', $input, $matches);
$result = $matches[1];

The pattern matches a space, php, more spaces, a string of non-spaces (the path), more spaces, and then captures the next string of non-spaces. The first space is mostly to ensure that you don't match php as part of a user name but really only as a command.

An alternative to capturing is the "keep" feature of PCRE. If you use \K in the pattern, everything before it is discarded in the match:

preg_match_all('/[ ]php[ ]+\S+[ ]+\K\S+/', $input, $matches);
$result = $matches[0];

I would use preg_match(). I do something similar for many of my system management scripts. Here is an example:

$test = "user     12052  0.2  0.1 137184 13056 ?        Ss   10:00   0:00 php /home/user/public_html/utilities/runProcFile.php cust1 cron
user     12054  0.2  0.1 137184 13064 ?        Ss   10:00   0:00 php /home/user/public_html/utilities/runProcFile.php cust3 cron
user     12055  0.6  0.1 137844 14220 ?        Ss   10:00   0:00 php /home/user/public_html/utilities/runProcFile.php cust4 cron
user     12057  0.2  0.1 137184 13052 ?        Ss   10:00   0:00 php /home/user/public_html/utilities/runProcFile.php cust89 cron
user     12058  0.2  0.1 137184 13052 ?        Ss   10:00   0:00 php /home/user/public_html/utilities/runProcFile.php cust435 cron
user     12059  0.3  0.1 135112 13000 ?        Ss   10:00   0:00 php /home/user/public_html/utilities/runProcFile.php cust16 cron
root     12068  0.0  0.0 106088  1164 pts/1    S+   10:00   0:00 sh -c ps aux | grep utilities > /home/user/public_html/logs/dashboard/currentlyPosting.txt
root     12070  0.0  0.0 103240   828 pts/1    R+   10:00   0:00 grep utilities";

$lines = explode("\n", $test);

foreach($lines as $line){
        if(preg_match("/.php[\s+](cust[\d]+)[\s+]cron/i", $line, $matches)){


The above prints:

    [0] => .php cust1 cron
    [1] => cust1
    [0] => .php cust3 cron
    [1] => cust3
    [0] => .php cust4 cron
    [1] => cust4
    [0] => .php cust89 cron
    [1] => cust89
    [0] => .php cust435 cron
    [1] => cust435
    [0] => .php cust16 cron
    [1] => cust16

You can set $test to equal the output from exec. the values you are looking for would be in the if statement under the foreach. $matches[1] will have the custx value.

How to stop VBA code running?

How about Application.EnableCancelKey - Use the Esc button

On Error GoTo handleCancel
Application.EnableCancelKey = xlErrorHandler
MsgBox "This may take a long time: press ESC to cancel"
For x = 1 To 1000000    ' Do something 1,000,000 times (long!)
    ' do something here
Next x

If Err = 18 Then
    MsgBox "You cancelled"
End If

Snippet from

How can I add a line to a file in a shell script?

sed is line based, so I'm not sure why you want to do this with sed. The paradigm is more processing one line at a time( you could also programatically find the # of fields in the CSV and generate your header line with awk) Why not just

echo "c1, c2, ... " >> file
cat testfile.csv >> file


Named tuple and default values for optional keyword arguments

Since you are using namedtuple as a data class, you should be aware that python 3.7 will introduce a @dataclass decorator for this very purpose -- and of course it has default values.

An example from the docs:

class C:
    a: int       # 'a' has no default value
    b: int = 0   # assign a default value for 'b'

Much cleaner, readable and usable than hacking namedtuple. It is not hard to predict that usage of namedtuples will drop with the adoption of 3.7.

Can I serve multiple clients using just Flask as standalone? accepts additional keyword arguments (**options) that it forwards to werkzeug.serving.run_simple - two of those arguments are threaded (a boolean) and processes (which you can set to a number greater than one to have werkzeug spawn more than one process to handle requests).

threaded defaults to True as of Flask 1.0, so for the latest versions of Flask, the default development server will be able to serve multiple clients simultaneously by default. For older versions of Flask, you can explicitly pass threaded=True to enable this behaviour.

For example, you can do

if __name__ == '__main__':

to handle multiple clients using threads in a way compatible with old Flask versions, or

if __name__ == '__main__':, processes=3)

to tell Werkzeug to spawn three processes to handle incoming requests, or just

if __name__ == '__main__':

to handle multiple clients using threads if you know that you will be using Flask 1.0 or later.

That being said, Werkzeug's serving.run_simple wraps the standard library's wsgiref package - and that package contains a reference implementation of WSGI, not a production-ready web server. If you are going to use Flask in production (assuming that "production" is not a low-traffic internal application with no more than 10 concurrent users) make sure to stand it up behind a real web server (see the section of Flask's docs entitled Deployment Options for some suggested methods).

warning: assignment makes integer from pointer without a cast

The warning comes from the fact that you're dereferencing src in the assignment. The expression *src has type char, which is an integral type. The expression "anotherstring" has type char [14], which in this particular context is implicitly converted to type char *, and its value is the address of the first character in the array. So, you wind up trying to assign a pointer value to an integral type, hence the warning. Drop the * from *src, and it should work as expected:

src = "anotherstring";

since the type of src is char *.

Using variables in Nginx location rules

This is many years late but since I found the solution I'll post it here. By using maps it is possible to do what was asked:

map $http_host $variable_name {

    default       /ap/;   /api/;
    * /whatever/;

server {
    location $variable_name/test {
        proxy_pass $auth_proxy;

If you need to share the same endpoint across multiple servers, you can also reduce the cost by simply defaulting the value:

map "" $variable_name {
    default       /test/;

Map can be used to initialise a variable based on the content of a string and can be used inside http scope allowing variables to be global and sharable across servers.

What is the meaning of CTOR?

Type "ctor" and press the TAB key twice this will add the default constructor automatically

Why does ANT tell me that JAVA_HOME is wrong when it is not?

I was also facing the same problem. I am using Windows 7 and I had two versions of java installed. First I have installed latest version java 7 and then version 5.

Contents of my java installation directory:

C:\Program Files\Java>

and my JAVA_HOME was set to the correct value, which was:

C:\>set ja
JAVA_HOME=C:\Program Files\Java\jdk1.5.0_14

But still I was getting the same problem:

XXXXXXX\build.xml:478: The following error occurred while
executing this line:
XXXXXXX\build.xml:477: Unable to find a javac compiler; is not on the classpath.
Perhaps JAVA_HOME does not point to the JDK.
It is currently set to "C:\Program Files\Java\jre7"

After trying out all the suggestion in this thread I realized my mistake. I was trying to set the environment variable in "User variables" instead of "System Variables" section. After setting it in "System Variables" it worked fine. I am facing another problem though.

The default version of java it points to is still 7.

C:\>java -version
java version "1.7.0_17"
Java(TM) SE Runtime Environment (build 1.7.0_17-b02)
Java HotSpot(TM) Client VM (build 23.7-b01, mixed mode, sharing)

I am not sure how to make it point to version 5.

How can I have Github on my own server?

you should check out this one:

It is written in PHP as you wanted it to be.

Pros/cons of using redux-saga with ES6 generators vs redux-thunk with ES2017 async/await

One quick note. Generators are cancellable, async/await — not. So for an example from the question, it does not really make sense of what to pick. But for more complicated flows sometimes there is no better solution than using generators.

So, another idea could be is to use generators with redux-thunk, but for me, it seems like trying to invent a bicycle with square wheels.

And of course, generators are easier to test.

How to find an object in an ArrayList by property

Here is a solution using Guava

private User findUserByName(List<User> userList, final String name) {
    Optional<User> userOptional =
            FluentIterable.from(userList).firstMatch(new Predicate<User>() {
                public boolean apply(@Nullable User input) {
                    return input.getName().equals(name);
    return userOptional.isPresent() ? userOptional.get() : null; // return user if found otherwise return null if user name don't exist in user list

Vertically centering a div inside another div

To center align both vertically and horizontally:


#child {

Android - How to download a file from a webserver

You should use an AsyncTask (or other way to perform a network operation on background).

protected void onCreate(Bundle savedInstanceState) {

    //create and execute the download task
    MyAsyncTask async = new MyAsyncTask();


private class MyAsyncTask extends AsyncTask<Void, Void, Void>{

    //execute on background (out of the UI thread)
    protected Long doInBackground(URL... urls) {


More info about AsyncTask on Android documentation

Hope it helps.

How to find Google's IP address?

The following IP address ranges belong to Google: - - - - - - -

Like many popular Web sites, Google utilizes multiple Internet servers to handle incoming requests to its Web site. Instead of entering into the browser, a person can enter http:// followed by one of the above addresses, for example:


Force page scroll position to top at page refresh in HTML

You can use location.replace instead of location.reload:


This way page will reload with scroll on top.

ASP.NET IIS Web.config [Internal Server Error]

I had the same problem.


  1. Click the right button in your site folder in "iis"
  2. "Convert to Application".

How to access the GET parameters after "?" in Express?

In my case with the given code, I was able to parse the value of the passed parameter in this way.

const express = require('express');
const bodyParser = require('body-parser');

const app = express(); 
app.use(bodyParser.urlencoded({ extended: false }));
let val1= req.body.par1;
let val2 = req.body.par2;

How store a range from excel into a Range variable?

here is an example that allows for performing code on each line of the desired areas (pick either from top & bottom of selection, of from selection

Sub doROWSb()           'WORKS    for do selected rows     SEE FIX ROWS ABOVE  (small ver)
Dim E7 As String    'note:  workcell E7 shows:  BG381
E7 = RANGE("E7")    'see eg below
Dim r As Long       'NOTE: this example has a paste formula(s) down a column(s).  WILL REDUCE 10 HOUR DAYS OF PASTING COLUMNS, DOWN TO 3 MINUTES?
Dim c As Long
Dim rCell As RANGE
'Dim LastRow As Long
r = ActiveCell.row
c = ActiveCell.Column   'might not matter if your code affects whole line anyways, still leave as is

Dim FirstRow As Long    'not in use, Delete if only want last row, note: this code already allows for selection as start
Dim LastRow As Long

If 1 Then     'if you are unable to delete rows not needed, just change 2 lines from: If 1, to if 0 (to go from selection last row, to all rows down from selection)
With Selection
    'FirstRow = .Rows(1).row                 'not used here, Delete if only want last row
    LastRow = .Rows(.Rows.Count).row        'find last row in selection
End With
application.CutCopyMode = False             'if not doing any paste op below
    LastRow = Cells(Rows.Count, 1).End(xlUp).row  'find last row used in sheet
End If
application.EnableEvents = True             'EVENTS  need this?
application.ScreenUpdating = False          'offset-cells(row, col)
RANGE("A1") = vbNullString                  'simple macros on-off switch, vb not here:  If RANGE("A1").Value > 0 Then

For Each rCell In RANGE(Cells(r, c), Cells(LastRow, c)) 'new
    rCell.Select    'make 3 macros for each paste macro below
'your code here:

If 1 Then     'to if 0, if want to paste formulas/formats/all down a column
    Selection.EntireRow.Calculate     'calcs all selected rows, even if just selecting 1 cell in each row (might only be doing 1 row aat here, as part of loop)
'dorows() DO ROWS()
'eg's for paste cells down a column, can make 3 separate macros for each: sub alte() altf & altp
      Selection.PasteSpecial Paste:=xlPasteFormulas, Operation:=xlNone, SkipBlanks:=False, Transpose:=False    'make sub alte ()    add thisworkbook:  application.OnKey "%{e}", "alte"
      'Selection.PasteSpecial Paste:=xlPasteFormats, Operation:=xlNone, SkipBlanks:=False, Transpose:=False     'make sub altf ()    add thisworkbook:  application.OnKey "%{f}", "altf"
      'Selection.PasteSpecial Paste:=xlPasteAll, Operation:=xlNone, SkipBlanks:=False, Transpose:=False         'amke sub altp ()    add thisworkbook:  application.OnKey "%{p}", "altp"
End If
Next rCell

'application.CutCopyMode = False            'finished - stop copy mode
goBEEPS (2), (0.25)       'beeps secs
application.EnableEvents = True             'EVENTS

'note:  workcell E7 has: SUBSTITUTE(SUBSTITUTE(CELL("address",$BG$369),"$",""),"","")
'other col eg (shows: BG:BG):  =SUBSTITUTE(SUBSTITUTE(CELL("address",$BG2),"$",""),ROW(),"")&":"& SUBSTITUTE(SUBSTITUTE(CELL("address",$BG2),"$",""),ROW(),"")
End Sub

Sub goBEEPSx(b As Long, t As Double)   'beeps secs as:  goBEEPS (2), (0.25)  OR:  goBEEPS(2, 0.25)
  Dim dt  'as double    'worked wo as double
  Dim x
  For b = b To 1 Step -1
    x = Timer
  dt = Timer - x
  If dt < 0 Then dt = dt + 86400    '86400 no. seconds in a day, in case hit midnight & timer went down to 0
  Loop Until dt >= t
End Sub

Disable and enable buttons in C#

It is this line button2.Enabled == true, it should be button2.Enabled = true. You are doing comparison when you should be doing assignment.

How can I convert an HTML element to a canvas element?

You can use dom-to-image library (I'm the maintainer).
Here's how you could approach your problem:

var parent = document.getElementById('my-node-parent');
var node = document.getElementById('my-node');

var canvas = document.createElement('canvas');
canvas.width = node.scrollWidth;
canvas.height = node.scrollHeight;

domtoimage.toPng(node).then(function (pngDataUrl) {
    var img = new Image();
    img.onload = function () {
        var context = canvas.getContext('2d');

        context.translate(canvas.width, 0);
        context.scale(-1, 1);
        context.drawImage(img, 0, 0);


    img.src = pngDataUrl;

And here is jsfiddle

MVC web api: No 'Access-Control-Allow-Origin' header is present on the requested resource

I had tried everything I could find on the net including the methods that have been given on this answer. After almost trying to solve the problem for whole day I have found the solution that have worked for me like a charm.

in the file WebApiConfig in folder App_Start, comment all the lines of code and add the following code:

`public static void Register(HttpConfiguration config)
        // Web API configuration and services
        var enableCorsAttribute = new EnableCorsAttribute("*",
                                           "Origin, Content-Type, Accept",
                                           "GET, PUT, POST, DELETE, OPTIONS");
        // Web API routes

            name: "DefaultApi",
            //routeTemplate: "api/{controller}/{id}",
            routeTemplate: "api/{controller}/{action}/{id}",
            defaults: new { id = RouteParameter.Optional }
        config.Formatters.Add(new BrowserJsonFormatter());

    public class BrowserJsonFormatter : JsonMediaTypeFormatter
        public BrowserJsonFormatter()
            this.SupportedMediaTypes.Add(new MediaTypeHeaderValue("text/html"));
            this.SerializerSettings.Formatting = Formatting.Indented;

        public override void SetDefaultContentHeaders(Type type, HttpContentHeaders headers, MediaTypeHeaderValue mediaType)
            base.SetDefaultContentHeaders(type, headers, mediaType);
            headers.ContentType = new MediaTypeHeaderValue("application/json");

Round integers to the nearest 10

This function will round either be order of magnitude (right to left) or by digits the same way that format treats floating point decimal places (left to right:

def intround(n, p):
    ''' rounds an intger. if "p"<0, p is a exponent of 10; if p>0, left to right digits '''
    if p==0: return n
    if p>0:  
        p=p-ln+1 if n<0 else p-ln
    return (n + 5 * 10**(-p-1)) // 10**-p * 10**-p

>>> tgt=5555555
>>> d=2
>>> print('\t{} rounded to {} places:\n\t{} right to left \n\t{} left to right'.format(
        tgt,d,intround(tgt,-d), intround(tgt,d))) 


5555555 rounded to 2 places:
5555600 right to left 
5600000 left to right

You can also use Decimal class:

import decimal
import sys

def ri(i, prec=6):
    ic=long if sys.version_info.major<3 else int
    with decimal.localcontext() as lct:
        if prec>0:
    return n

On Python 3 you can reliably use round with negative places and get a rounded integer:

def intround2(n, p):
    ''' will fail with larger floating point numbers on Py2 and require a cast to an int '''
    if p>0:
        return round(n, p-len(str(n))+1)
        return round(n, p)    

On Python 2, round will fail to return a proper rounder integer on larger numbers because round always returns a float:

>>> round(2**34, -5)
17179900000.0                     # OK
>>> round(2**64, -5)
1.84467440737096e+19              # wrong 

The other 2 functions work on Python 2 and 3

How to print a list in Python "nicely"

As other answers have mentioned, pprint is a great module that will do what you want. However if you don't want to import it and just want to print debugging output during development, you can approximate its output.

Some of the other answers work fine for strings, but if you try them with a class object it will give you the error TypeError: sequence item 0: expected string, instance found.

For more complex objects, make sure the class has a __repr__ method that prints the property information you want:

class Foo(object):
    def __init__(self, bar): = bar

    def __repr__(self):
        return "Foo - (%r)" %

And then when you want to print the output, simply map your list to the str function like this:

l = [Foo(10), Foo(20), Foo("A string"), Foo(2.4)]
print "[%s]" % ",\n ".join(map(str,l))


 [Foo - (10),
  Foo - (20),
  Foo - ('A string'),
  Foo - (2.4)]

You can also do things like override the __repr__ method of list to get a form of nested pretty printing:

class my_list(list):
    def __repr__(self):
        return "[%s]" % ",\n ".join(map(str, self))

a = my_list(["first", 2, my_list(["another", "list", "here"]), "last"])
print a



Unfortunately no second-level indentation but for a quick debug it can be useful.

Google Recaptcha v3 example demo

I process POST on PHP from an angular ajax call. I also like to see the SCORE from google.

This works well for me...

$postData = json_decode(file_get_contents('php://input'), true); //get data sent via post
$captcha = $postData['g-recaptcha-response'];

header('Content-Type: application/json');
if($captcha === ''){
    //Do something with error
    echo '{ "status" : "bad", "score" : "none"}';
} else {
    $secret   = 'your-secret-key';
    $response = file_get_contents(
        "" . $secret . "&response=" . $captcha . "&remoteip=" . $_SERVER['REMOTE_ADDR']
    // use json_decode to extract json response
    $response = json_decode($response);

    if ($response->success === false) {
        //Do something with error
        echo '{ "status" : "bad", "score" : "none"}';
    }else if ($response->success==true && $response->score <= 0.5) {
        echo '{ "status" : "bad", "score" : "'.$response->score.'"}';
    }else {
        echo '{ "status" : "ok", "score" : "'.$response->score.'"}';


<input type="hidden" id="g-recaptcha-response" name="g-recaptcha-response">

On js

    var params = {
                     method: 'POST',
                     url: 'api/recaptcha.php',
                     headers: {
                       'Content-Type': undefined
                     data:   {'g-recaptcha-response' : myCaptcha }
     }, function(response){

Check if an object belongs to a class in Java

If you ever need to do this dynamically, you can use the following:

boolean isInstance(Object object, Class<?> type) {
    return type.isInstance(object);

You can get an instance of java.lang.Class by calling the instance method Object::getClass on any object (returns the Class which that object is an instance of), or you can do class literals (for example, String.class, List.class, int[].class). There are other ways as well, through the reflection API (which Class itself is the entry point for).

How to delete an element from a Slice in Golang

To remove an element from the middle of a slice, preserving the order of the remaining elements, use copy to slide the higher-numbered elements down by one to fill the gap:

func remove(slice []int, i int) []int {
  copy(slice[i:], slice[i+1:])
  return slice[:len(slice)-1]

If it is not necessary to preserve the order, we can simply move the last element to the gap.

func remove(slice []int, i int) []int {
  slice[i] = slice[len(slice)-1]
  return slice[:len(slice)-1]

How to set xampp open localhost:8080 instead of just localhost

I agree and found this file under xammp-control the type of file is configuration. When I changed it to 8080 it worked automagically!

How can I insert data into Database Laravel?

make sure you use the POST to insert the data. Actually you were using GET.

How to convert a Java 8 Stream to an Array?

Stream<Integer> stream = Stream.of(1, 2, 3, 4, 5, 6);

int[] arr=   stream.mapToInt(x->x.intValue()).toArray();

Can't include C++ headers like vector in Android NDK

In android NDK go to android-ndk-r9b>/sources/cxx-stl/gnu-libstdc++/4.X/include in linux machines

I've found solution from the below link

Check to see if python script is running

try this:

#/usr/bin/env python
import os, sys, atexit

    # Set PID file
    def set_pid_file():
        pid = str(os.getpid())
        f = open('', 'w')

    def goodby():
        pid = str('')

    # Place your code here

except KeyboardInterrupt:

Int division: Why is the result of 1/3 == 0?

The conversion in JAVA is quite simple but need some understanding. As explain in the JLS for integer operations:

If an integer operator other than a shift operator has at least one operand of type long, then the operation is carried out using 64-bit precision, and the result of the numerical operator is of type long. If the other operand is not long, it is first widened (§5.1.5) to type long by numeric promotion (§5.6).

And an example is always the best way to translate the JLS ;)

int + long -> long
int(1) + long(2) + int(3) -> long(1+2) + long(3)

Otherwise, the operation is carried out using 32-bit precision, and the result of the numerical operator is of type int. If either operand is not an int, it is first widened to type int by numeric promotion.

short + int -> int + int -> int

A small example using Eclipse to show that even an addition of two shorts will not be that easy :

short s = 1;
s = s + s; <- Compiling error

//possible loss of precision
//  required: short
//  found:    int

This will required a casting with a possible loss of precision.

The same is true for the floating point operators

If at least one of the operands to a numerical operator is of type double, then the operation is carried out using 64-bit floating-point arithmetic, and the result of the numerical operator is a value of type double. If the other operand is not a double, it is first widened (§5.1.5) to type double by numeric promotion (§5.6).

So the promotion is done on the float into double.

And the mix of both integer and floating value result in floating values as said

If at least one of the operands to a binary operator is of floating-point type, then the operation is a floating-point operation, even if the other is integral.

This is true for binary operators but not for "Assignment Operators" like +=

A simple working example is enough to prove this

int i = 1;
i += 1.5f;

The reason is that there is an implicit cast done here, this will be execute like

i = (int) i + 1.5f
i = (int) 2.5f
i = 2

Get value of input field inside an iframe

<iframe id="upload_target" name="upload_target">
    <textarea rows="20" cols="100" name="result" id="result" ></textarea>
    <input type="text" id="txt1" />

You can Get value by JQuery


work on only same domain link

Why is setState in reactjs Async instead of Sync?

1) setState actions are asynchronous and are batched for performance gains. This is explained in the documentation of setState.

setState() does not immediately mutate this.state but creates a pending state transition. Accessing this.state after calling this method can potentially return the existing value. There is no guarantee of synchronous operation of calls to setState and calls may be batched for performance gains.

2) Why would they make setState async as JS is a single threaded language and this setState is not a WebAPI or server call?

This is because setState alters the state and causes rerendering. This can be an expensive operation and making it synchronous might leave the browser unresponsive.

Thus the setState calls are asynchronous as well as batched for better UI experience and performance.

Twitter bootstrap scrollable modal

Your modal is being hidden in firefox, and that is because of the negative margin declaration you have inside your general stylesheet:

.modal {
    margin-top: -45%; /* remove this */
    max-height: 90%;
    overflow-y: auto;

Remove the negative margin and everything works just fine.

Looping through GridView rows and Checking Checkbox Control

you have to iterate gridview Rows

for (int count = 0; count < grd.Rows.Count; count++)
    if (((CheckBox)grd.Rows[count].FindControl("yourCheckboxID")).Checked)

clear data inside text file in c++

If you set the trunc flag.


using namespace std;

fstream ofs;

int main(){"test.txt", ios::out | ios::trunc);
ofs<<"Your content here";
ofs.close(); //Using microsoft incremental linker version 14

I tested this thouroughly for my own needs in a common programming situation I had. Definitely be sure to preform the ".close();" operation. If you don't do this there is no telling whether or not you you trunc or just app to the begging of the file. Depending on the file type you might just append over the file which depending on your needs may not fullfill its purpose. Be sure to call ".close();" explicity on the fstream you are trying to replace.

how to resolve DTS_E_OLEDBERROR. in ssis

I would start by turning off TCP offloading. There have been a few things that cause intermittent connectivity issues and this is the one that is usually the culprit.

Note: I have seen this setting cause problems on Win Server 2003 and Win Server 2008

javascript: optional first argument in function

With ES6:

function test(a, b = 3) {
   console.log(a, ' ', b);

test(1);      // Output: 1 3
test(1, 2);   // Output: 1 2

How do I format date in jQuery datetimepicker?

you can use :

        format:'d.m.Y H:i',
        minDate: ge_today_date(new Date())

 function ge_today_date(date) {
     var day = date.getDate();
     var month = date.getMonth() + 1;
     var year = date.getFullYear().toString().slice(2);
     return day + '-' + month + '-' + year;

How do I declare a namespace in JavaScript?

I normally build it in a closure:

var MYNS = MYNS || {};

MYNS.subns = (function() {

    function privateMethod() {
        // Do private stuff, or build internal.
        return "Message";

    return {
        someProperty: 'prop value',
        publicMethod: function() {
            return privateMethod() + " stuff";

My style over the years has had a subtle change since writing this, and I now find myself writing the closure like this:

var MYNS = MYNS || {};

MYNS.subns = (function() {
    var internalState = "Message";

    var privateMethod = function() {
        // Do private stuff, or build internal.
        return internalState;
    var publicMethod = function() {
        return privateMethod() + " stuff";

    return {
        someProperty: 'prop value',
        publicMethod: publicMethod

In this way I find the public API and implementation easier to understand. Think of the return statement as being a public interface to the implementation.

How can I get a collection of keys in a JavaScript dictionary?

Use Object.keys() or shim it in older browsers...

const keys = Object.keys(driversCounter);

If you wanted values, there is Object.values() and if you want key and value, you can use Object.entries(), often paired with Array.prototype.forEach() like this...

Object.entries(driversCounter).forEach(([key, value]) => {
   console.log(key, value);

Alternatively, considering your use case, maybe this will do it...

var selectBox, option, prop;

selectBox = document.getElementById("drivers");

for (prop in driversCounter) {
   option = document.createElement("option");
   option.textContent = prop;
   option.value = driversCounter[prop];

Why would one omit the close tag?

It isn't a tag…

But if you have it, you risk having white space after it.

If you then use it as an include at the top of a document, you could end up inserting white space (i.e. content) before you attempt to send HTTP headers … which isn't allowed.

How do I pass a variable by reference?

Arguments are passed by assignment. The rationale behind this is twofold:

  1. the parameter passed in is actually a reference to an object (but the reference is passed by value)
  2. some data types are mutable, but others aren't


  • If you pass a mutable object into a method, the method gets a reference to that same object and you can mutate it to your heart's delight, but if you rebind the reference in the method, the outer scope will know nothing about it, and after you're done, the outer reference will still point at the original object.

  • If you pass an immutable object to a method, you still can't rebind the outer reference, and you can't even mutate the object.

To make it even more clear, let's have some examples.

List - a mutable type

Let's try to modify the list that was passed to a method:

def try_to_change_list_contents(the_list):
    print('got', the_list)
    print('changed to', the_list)

outer_list = ['one', 'two', 'three']

print('before, outer_list =', outer_list)
print('after, outer_list =', outer_list)


before, outer_list = ['one', 'two', 'three']
got ['one', 'two', 'three']
changed to ['one', 'two', 'three', 'four']
after, outer_list = ['one', 'two', 'three', 'four']

Since the parameter passed in is a reference to outer_list, not a copy of it, we can use the mutating list methods to change it and have the changes reflected in the outer scope.

Now let's see what happens when we try to change the reference that was passed in as a parameter:

def try_to_change_list_reference(the_list):
    print('got', the_list)
    the_list = ['and', 'we', 'can', 'not', 'lie']
    print('set to', the_list)

outer_list = ['we', 'like', 'proper', 'English']

print('before, outer_list =', outer_list)
print('after, outer_list =', outer_list)


before, outer_list = ['we', 'like', 'proper', 'English']
got ['we', 'like', 'proper', 'English']
set to ['and', 'we', 'can', 'not', 'lie']
after, outer_list = ['we', 'like', 'proper', 'English']

Since the the_list parameter was passed by value, assigning a new list to it had no effect that the code outside the method could see. The the_list was a copy of the outer_list reference, and we had the_list point to a new list, but there was no way to change where outer_list pointed.

String - an immutable type

It's immutable, so there's nothing we can do to change the contents of the string

Now, let's try to change the reference

def try_to_change_string_reference(the_string):
    print('got', the_string)
    the_string = 'In a kingdom by the sea'
    print('set to', the_string)

outer_string = 'It was many and many a year ago'

print('before, outer_string =', outer_string)
print('after, outer_string =', outer_string)


before, outer_string = It was many and many a year ago
got It was many and many a year ago
set to In a kingdom by the sea
after, outer_string = It was many and many a year ago

Again, since the the_string parameter was passed by value, assigning a new string to it had no effect that the code outside the method could see. The the_string was a copy of the outer_string reference, and we had the_string point to a new string, but there was no way to change where outer_string pointed.

I hope this clears things up a little.

EDIT: It's been noted that this doesn't answer the question that @David originally asked, "Is there something I can do to pass the variable by actual reference?". Let's work on that.

How do we get around this?

As @Andrea's answer shows, you could return the new value. This doesn't change the way things are passed in, but does let you get the information you want back out:

def return_a_whole_new_string(the_string):
    new_string = something_to_do_with_the_old_string(the_string)
    return new_string

# then you could call it like
my_string = return_a_whole_new_string(my_string)

If you really wanted to avoid using a return value, you could create a class to hold your value and pass it into the function or use an existing class, like a list:

def use_a_wrapper_to_simulate_pass_by_reference(stuff_to_change):
    new_string = something_to_do_with_the_old_string(stuff_to_change[0])
    stuff_to_change[0] = new_string

# then you could call it like
wrapper = [my_string]


Although this seems a little cumbersome.

Understanding events and event handlers in C#

I recently made an example of how to use events in c#, and posted it on my blog. I tried to make it as clear as possible, with a very simple example. In case it might help anyone, here it is:

It includes description and source code (with lots of comments), and it mainly focuses on a proper (template - like) usage of events and event handlers.

Some key points are:

  • Events are like "sub - types of delegates", only more constrained (in a good way). In fact an event's declaration always includes a delegate (EventHandlers are a type of delegate).

  • Event Handlers are specific types of delegates (you may think of them as a template), which force the user to create events which have a specific "signature". The signature is of the format: (object sender, EventArgs eventarguments).

  • You may create your own sub-class of EventArgs, in order to include any type of information the event needs to convey. It is not necessary to use EventHandlers when using events. You may completely skip them and use your own kind of delegate in their place.

  • One key difference between using events and delegates, is that events can only be invoked from within the class that they were declared in, even though they may be declared as public. This is a very important distinction, because it allows your events to be exposed so that they are "connected" to external methods, while at the same time they are protected from "external misuse".

Get button click inside UITableViewCell

Its Work For me.

 - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
     UIButton *Btn_Play = (UIButton *)[cell viewWithTag:101];
     [Btn_Play addTarget:self action:@selector(ButtonClicked:) forControlEvents:UIControlEventTouchUpInside];
-(void)ButtonClicked:(UIButton*)sender {
     CGPoint buttonPosition = [sender convertPoint:CGPointZero toView:self.Tbl_Name];
     NSIndexPath *indexPath = [self.Tbl_Name indexPathForRowAtPoint:buttonPosition];

Radio/checkbox alignment in HTML/CSS

I found the best fix for this was to give the input a height that matches the label. At least this fixed my problem with inconsistencies in Firefox and IE.

input { height: 18px; margin: 0; float: left; }
label { height: 18px; float: left; }

  <input id="option1" type="radio" name="opt" />
  <label for="option1">Option 1</label>

Delete all the records

I can see the that the others answers shown above are right, but I'll make your life easy.

I even created an example for you. I added some rows and want delete them.

You have to right click on the table and as shown in the figure Script Table a> Delete to> New query Editor widows:

enter image description here

Then another window will open with a script. Delete the line of "where", because you want to delete all rows. Then click Execute.

enter image description here

To make sure you did it right right click over the table and click in "Select Top 1000 rows". Then you can see that the query is empty.

What is Node.js' Connect, Express and "middleware"?

Connect offers a "higher level" APIs for common HTTP server functionality like session management, authentication, logging and more. Express is built on top of Connect with advanced (Sinatra like) functionality.

How do I add a placeholder on a CharField in Django?

class FormClass(forms.ModelForm):
    class Meta:
        model = Book
        fields = '__all__'
        widgets = {
            'field_name': forms.TextInput(attrs={'placeholder': 'Type placeholder text here..'}),

Singleton design pattern vs Singleton beans in Spring container

I find "per container per bean" difficult to apprehend. I would say "one bean per bean id in a container".Lets have an example to understand it. We have a bean class Sample. I have defined two beans from this class in bean definition, like:

<bean id="id1" class="com.example.Sample" scope="singleton">
        <property name="name" value="James Bond 001"/>    
<bean id="id7" class="com.example.Sample" scope="singleton">
        <property name="name" value="James Bond 007"/>    

So when ever I try to get the bean with id "id1",the spring container will create one bean, cache it and return same bean where ever refered with id1. If I try to get it with id7, another bean will be created from Sample class, same will be cached and returned each time you referred that with id7.

This is unlikely with Singleton pattern. In Singlton pattern one object per class loader is created always. However in Spring, making the scope as Singleton does not restrict the container from creating many instances from that class. It just restricts new object creation for the same ID again, returning previously created object when an object is requested for the same id. Reference

How to change spinner text size and text color?

Rather than making a custom layout to get a small size and if you want to use Android's internal small size LAYOUT for the spinner, you should use:

"android.R.layout.simple_gallery_item" instead of "android.R.layout.simple_spinner_item".

ArrayAdapter<CharSequence> madaptor = ArrayAdapter

It can reduce the size of spinner's layout. It's just a simple trick.

If you want to reduce the size of a drop down list use this:


Can I call an overloaded constructor from another constructor of the same class in C#?

EDIT: According to the comments on the original post this is a C# question.

Short answer: yes, using the this keyword.

Long answer: yes, using the this keyword, and here's an example.

class MyClass
   private object someData;

   public MyClass(object data)
      this.someData = data;

   public MyClass() : this(new object())
      // Calls the previous constructor with a new object, 
      // setting someData to that object

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

Both answers are correct. If you user .TO -method then the semicolumn is OK - but not for the addrecipients-method. There you need to split, e.g. :

                Dim Splitter() As String
                Splitter = Split(AddrMail, ";")
                For Each Dest In Splitter
                    .Recipients.Add (Trim(Dest))

How to use NSURLConnection to connect with SSL for an untrusted cert?

To complement the accepted answer, for much better security, you could add your server certificate or your own root CA certificate to keychain(, however doing this alone won't make NSURLConnection authenticate your self-signed server automatically. You still need to add the below code to your NSURLConnection delegate, it's copied from Apple sample code AdvancedURLConnections, and you need to add two files(Credentials.h, Credentials.m) from apple sample code to your projects.

- (BOOL)connection:(NSURLConnection *)connection canAuthenticateAgainstProtectionSpace:(NSURLProtectionSpace *)protectionSpace {
return [protectionSpace.authenticationMethod isEqualToString:NSURLAuthenticationMethodServerTrust];

- (void)connection:(NSURLConnection *)connection didReceiveAuthenticationChallenge:(NSURLAuthenticationChallenge *)challenge {
if ([challenge.protectionSpace.authenticationMethod isEqualToString:NSURLAuthenticationMethodServerTrust]) {
//        if ([trustedHosts])

    OSStatus                err;
    NSURLProtectionSpace *  protectionSpace;
    SecTrustRef             trust;
    SecTrustResultType      trustResult;
    BOOL                    trusted;

    protectionSpace = [challenge protectionSpace];
    assert(protectionSpace != nil);

    trust = [protectionSpace serverTrust];
    assert(trust != NULL);
    err = SecTrustEvaluate(trust, &trustResult);
    trusted = (err == noErr) && ((trustResult == kSecTrustResultProceed) || (trustResult == kSecTrustResultUnspecified));

    // If that fails, apply our certificates as anchors and see if that helps.
    // It's perfectly acceptable to apply all of our certificates to the SecTrust
    // object, and let the SecTrust object sort out the mess.  Of course, this assumes
    // that the user trusts all certificates equally in all situations, which is implicit
    // in our user interface; you could provide a more sophisticated user interface
    // to allow the user to trust certain certificates for certain sites and so on).

    if ( ! trusted ) {
        err = SecTrustSetAnchorCertificates(trust, (CFArrayRef) [Credentials sharedCredentials].certificates);
        if (err == noErr) {
            err = SecTrustEvaluate(trust, &trustResult);
        trusted = (err == noErr) && ((trustResult == kSecTrustResultProceed) || (trustResult == kSecTrustResultUnspecified));
        [challenge.sender useCredential:[NSURLCredential credentialForTrust:challenge.protectionSpace.serverTrust] forAuthenticationChallenge:challenge];

[challenge.sender continueWithoutCredentialForAuthenticationChallenge:challenge];

Swift convert unix time to date and time

You can get a date with that value by using the NSDate(withTimeIntervalSince1970:) initializer:

let date = NSDate(timeIntervalSince1970: 1415637900)

What's the best way to add a full screen background image in React Native

UPDATE to ImageBackground

Since using <Image /> as a container is deprecated for a while, all answers actually miss something important. For proper use choose <ImageBackground /> with style and imageStyle prop. Apply all Image relevant styles to imageStyle.

For example:

      backgroundColor: '#fc0',
      width: '100%', // applied to Image
      height: '100%' 
      resizeMode: 'contain' // works only here!
    <Text>Some Content</Text>

'adb' is not recognized as an internal or external command, operable program or batch file

This answer assumes that the PATH has been correctly set as described in the other answers

If you're on Windows 10 and dont have Admin rights then right click on the CMD, powershell ... program and select run as administrator. Then try adb [command]

Whoops, looks like something went wrong. Laravel 5.0

Simply type in terminal in your command prompt go to laravel directory path and type php artisan key:generate then key will be generated. Paste that key in config/app.php key variable. Your problem will be solved. I also did like that inorder to solve the problem...

What is the .idea folder?

There is no problem in deleting this. It's not only the WebStorm IDE creating this file, but also PhpStorm and all other of JetBrains' IDEs.

It is safe to delete it but if your project is from GitLab or GitHub then you will see a warning.

JavaScript/regex: Remove text between parentheses

var str = "Hello, this is Mike (example)";

alert(str.replace(/\s*\(.*?\)\s*/g, ''));

That'll also replace excess whitespace before and after the parentheses.

Append TimeStamp to a File Name

Perhaps appending DateTime.Now.Ticks instead, is a tiny bit faster since you won't be creating 3 strings and the ticks value will always be unique also.

Fast way to concatenate strings in nodeJS/JavaScript

The question is already answered, however when I first saw it I thought of NodeJS Buffer. But it is way slower than the +, so it is likely that nothing can be faster than + in string concetanation.

Tested with the following code:

function a(){
    var s = "hello";
    var p = "world";
    s = s + p;
    return s;

function b(){
    var s = new Buffer("hello");
    var p = new Buffer("world");
    s = Buffer.concat([s,p]);
    return s;

var times = 100000;

var t1 = new Date();
for( var i = 0; i < times; i++){

var t2 = new Date();
console.log("Normal took: " + (t2-t1) + " ms.");
for ( var i = 0; i < times; i++){

var t3 = new Date();

console.log("Buffer took: " + (t3-t2) + " ms.");


Normal took: 4 ms.
Buffer took: 458 ms.

How to create an empty file with Ansible?

file module provide way to touch file without modifying its time.

- name: Touch again the same file, but dont change times this makes the task idempotent
    path: /etc/foo.conf
    state: touch
    mode: u+rw,g-wx,o-rwx
    modification_time: preserve
    access_time: preserve


How to "pretty" format JSON output in Ruby on Rails

Using <pre> HTML code and pretty_generate is good trick:

  require 'json'

  hash = JSON[{hey: "test", num: [{one: 1, two: 2, threes: [{three: 3, tthree: 33}]}]}.to_json] 

  <%=  JSON.pretty_generate(hash) %>

Android ListView not refreshing after notifyDataSetChanged

Look at your onResume method in ItemFragment:

public void onResume() {
    items = dbHelper.getItems(); // reload the items from database

what you just have updated before calling notifyDataSetChanged() is not the adapter's field private List<Item> items; but the identically declared field of the fragment. The adapter still stores a reference to list of items you passed when you created the adapter (e.g. in fragment's onCreate). The shortest (in sense of number of changes) but not elegant way to make your code behave as you expect is simply to replace the line:

    items = dbHelper.getItems(); // reload the items from database


    items.addAll(dbHelper.getItems()); // reload the items from database

A more elegant solution:

1) remove items private List<Item> items; from ItemFragment - we need to keep reference to them only in adapter

2) change onCreate to :

public void onCreate(Bundle savedInstanceState) {
    dbHelper = new DatabaseHandler(getActivity());
    adapter = new ItemAdapter(getActivity(), dbHelper.getItems());

3) add method in ItemAdapter:

public void swapItems(List<Item> items) {
    this.items = items;

4) change your onResume to:

public void onResume() {

Register 32 bit COM DLL to 64 bit Windows 7

I was getting the error "The module may compatible with this version of windows" for both version of RegSvr32 (32 bit and 64 bit). I was trying to register a DLL that was built for XP (32 bit) in Server 2008 R2 (x64) and none of the Regsr32 resolutions worked for me. However, registering the assembly in the appropriate .Net worked perfect for me. C:\Windows\Microsoft.NET\Framework\v2.0.50727\RegAsm.exe

R Plotting confidence bands with ggplot


mp <-data.frame(year=1990:2010)
N <- nrow(mp)

mp <- within(mp,
             wav <- rnorm(N)*cos(2*pi*year)+rnorm(N)*sin(2*pi*year)+5
             wow <- rnorm(N)*wav+rnorm(N)*wav^3

m01 <- gls(wow~poly(wav,3), data=mp, correlation = corARMA(p=1))

Get fitted values (the same as m01$fitted)

fit <- predict(m01)

Normally we could use something like predict(..., to get the confidence intervals on the prediction, but gls doesn't provide this capability. We use a recipe similar to the one shown at :

V <- vcov(m01)
X <- model.matrix(~poly(wav,3),data=mp) <- sqrt(diag(X %*% V %*% t(X)))

Put together a "prediction frame":

predframe <- with(mp,data.frame(year,wav,

Now plot with geom_ribbon

(p1 <- ggplot(mp, aes(year, wow))+

year vs wow

It's easier to see that we got the right answer if we plot against wav rather than year:

(p2 <- ggplot(mp, aes(wav, wow))+

wav vs wow

It would be nice to do the predictions with more resolution, but it's a little tricky to do this with the results of poly() fits -- see ?makepredictcall.

Html.fromHtml deprecated in Android N

Try the following to support basic html tags including ul ol li tags. Create a Tag handler as shown below

import org.xml.sax.XMLReader;

import android.os.Bundle;
import android.text.Editable;
import android.text.Html;
import android.text.Html.TagHandler;
import android.util.Log;

public class MyTagHandler implements TagHandler {
    boolean first= true;
    String parent=null;
    int index=1;
    public void handleTag(boolean opening, String tag, Editable output,
                          XMLReader xmlReader) {

        if(tag.equals("ul")) parent="ul";
        else if(tag.equals("ol")) parent="ol";
                    first= false;
                    first = true;
                    output.append("\n\t"+index+". ");
                    first= false;
                    first = true;

Set the text on Activity as shown below

    public void init(){
        try {
            TextView help = (TextView) findViewById(;
            if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.N) {
                help.setText(Html.fromHtml(getString(R.string.help_html),Html.FROM_HTML_MODE_LEGACY, null, new MyTagHandler()));
            } else {
                help.setText(Html.fromHtml(getString(R.string.help_html), null, new MyTagHandler()));
        } catch (Exception e) {


And html text on resource string files as

<![CDATA[ ...raw html data ...]] >

ListBox vs. ListView - how to choose for data binding

A ListView is a specialized ListBox (that is, it inherits from ListBox). It allows you to specify different views rather than a straight list. You can either roll your own view, or use GridView (think explorer-like "details view"). It's basically the multi-column listbox, the cousin of windows form's listview.

If you don't need the additional capabilities of ListView, you can certainly use ListBox if you're simply showing a list of items (Even if the template is complex).

OperationalError: database is locked

The practical reason for this is often that the python or django shells have opened a request to the DB and it wasn't closed properly; killing your terminal access often frees it up. I had this error on running command line tests today.

Edit: I get periodic upvotes on this. If you'd like to kill access without rebooting the terminal, then from commandline you can do:

from django import db

What's the proper value for a checked attribute of an HTML checkbox?

I think this may help:

First read all the specs from Microsoft and
You'd see that the setting the actual element of a checkbox needs to be done on the ELEMENT PROPERTY, not the UI or attribute.

Secondly, you need to be aware that the checked attribute RETURNS a string "true", "false"
Why is this important? Because you need to use the correct Type. A string, not a boolean. This also important when parsing your checkbox.
$('mycheckbox')[0].checked = "true"

if($('mycheckbox')[0].checked === "true"){ //do something }

You also need to realize that the "checked" ATTRIBUTE is for setting the value of the checkbox initially. This doesn't do much once the element is rendered to the DOM. Picture this working when the webpage loads and is initially parsed.
I'll go with IE's preference on this one: <input type="checkbox" checked="checked"/>

Lastly, the main aspect of confusion for a checkbox is that the checkbox UI element is not the same as the element's property value. They do not correlate directly. If you work in .net, you'll discover that the user "checking" a checkbox never reflects the actual bool value passed to the controller. To set the UI, I use both $('mycheckbox').val(true); and $('mycheckbox').attr('checked', 'checked');

In short, for a checked checkbox you need:
Initial DOM: <input type="checkbox" checked="checked">
Element Property: $('mycheckbox')[0].checked = "true";
UI: $('mycheckbox').val(true); and $('mycheckbox').attr('checked', 'checked');

Why doesn't height: 100% work to expand divs to the screen height?

This may not be ideal but you can allways do it with javascript. Or in my case jQuery

var newheight = $('.innerdiv').css('height');
$('.mainwrapper').css('height', newheight);

Difference between git pull and git pull --rebase

Sometimes we have an upstream that rebased/rewound a branch we're depending on. This can be a big problem -- causing messy conflicts for us if we're downstream.

The magic is git pull --rebase

A normal git pull is, loosely speaking, something like this (we'll use a remote called origin and a branch called foo in all these examples):

# assume current checked out branch is "foo"
git fetch origin
git merge origin/foo

At first glance, you might think that a git pull --rebase does just this:

git fetch origin
git rebase origin/foo

But that will not help if the upstream rebase involved any "squashing" (meaning that the patch-ids of the commits changed, not just their order).

Which means git pull --rebase has to do a little bit more than that. Here's an explanation of what it does and how.

Let's say your starting point is this:

a---b---c---d---e  (origin/foo) (also your local "foo")

Time passes, and you have made some commits on top of your own "foo":

a---b---c---d---e---p---q---r (foo)

Meanwhile, in a fit of anti-social rage, the upstream maintainer has not only rebased his "foo", he even used a squash or two. His commit chain now looks like this:

a---b+c---d+e---f  (origin/foo)

A git pull at this point would result in chaos. Even a git fetch; git rebase origin/foo would not cut it, because commits "b" and "c" on one side, and commit "b+c" on the other, would conflict. (And similarly with d, e, and d+e).

What git pull --rebase does, in this case, is:

git fetch origin
git rebase --onto origin/foo e foo

This gives you:

 a---b+c---d+e---f---p'---q'---r' (foo)

You may still get conflicts, but they will be genuine conflicts (between p/q/r and a/b+c/d+e/f), and not conflicts caused by b/c conflicting with b+c, etc.

Answer taken from (and slightly modified):

How to POST a JSON object to a JAX-RS service

I faced the same 415 http error when sending objects, serialized into JSON, via PUT/PUSH requests to my JAX-rs services, in other words my server was not able to de-serialize the objects from JSON. In my case, the server was able to serialize successfully the same objects in JSON when sending them into its responses.

As mentioned in the other responses I have correctly set the Accept and Content-Type headers to application/json, but it doesn't suffice.


I simply forgot a default constructor with no parameters for my DTO objects. Yes this is the same reasoning behind @Entity objects, you need a constructor with no parameters for the ORM to instantiate objects and populate the fields later.

Adding the constructor with no parameters to my DTO objects solved my issue. Here follows an example that resembles my code:


public class NumberDTO {
    public NumberDTO(Number number) {
        this.number = number;

    private Number number;

    public Number getNumber() {
        return number;

    public void setNumber(Number string) {
        this.number = string;


public class NumberDTO {

    public NumberDTO() {

    public NumberDTO(Number number) {
        this.number = number;

    private Number number;

    public Number getNumber() {
        return number;

    public void setNumber(Number string) {
        this.number = string;

I lost hours, I hope this'll save yours ;-)

C++ queue - simple example

Simply declare it as below if you want to us the STL queue container.

std::queue<myclass*> my_queue;

CSS background opacity with rgba not working in IE 8

Though late, I had to use that today and found a very useful php script here that will allow you to dynamically create a png file, much like the way rgba works.

background: url(rgba.php?r=255&g=100&b=0&a=50) repeat;
background: rgba(255,100,0,0.5);

The script can be downloaded here:

I know it may not be the perfect solution for everybody, but it's worth considering in some cases, since it saves a lot of time and works flawlessly. Hope that helps somebody!

Get safe area inset top and bottom heights

extension UIViewController {
    var topbarHeight: CGFloat {
            (view.window? ?? 0) +
            (view.window?.windowScene?.statusBarManager?.statusBarFrame.height ?? 0.0) +
            (self.navigationController?.navigationBar.frame.height ?? 0.0)

How to do a SOAP wsdl web services call from the command line

For Windows:

Save the following as MSFT.vbs:

set SOAPClient = createobject("MSSOAP.SOAPClient")
SOAPClient.mssoapinit ""
WScript.Echo "MSFT = " & SOAPClient.GetQuote("MSFT")

Then from a command prompt, run:



How to open Visual Studio Code from the command line on OSX?

If you're using visual code insiders and you want to open a file or folder in Visual Studio Code insiders from your terminal or any other command line tool then you can refer to the commands below which come by default inside visual studio code insider.

To open Visual Studio Code from command line

code-insiders --

To open the entire folder/directory

code-insiders .

To open a specific file

code-insiders file_name

eg:- code index.html

Javascript: getFullyear() is not a function

You are overwriting the start date object with the value of a DOM Element with an id of Startdate.

This should work:

var start = new Date(document.getElementById('Stardate').value);

var y = start.getFullYear();

Is this very likely to create a memory leak in Tomcat?

Sometimes this has to do with configuration changes. When we upgraded from Tomncat 6.0.14 to 6.0.26, we had seen something similar. here is the solution

Sql Query to list all views in an SQL Server 2005 database

To finish the set off (with what has already been suggested):

SELECT * FROM sys.views

This gives extra properties on each view, not available from sys.objects (which contains properties common to all types of object) or INFORMATION_SCHEMA.VIEWS. Though INFORMATION_SCHEMA approach does provide the view definition out-of-the-box.

How do I list one filename per output line in Linux?

You can also use ls -w1

This allows to set number of columns. From manpage of ls:

   -w, --width=COLS
          set output width to COLS.  0 means no limit

Execute ssh with password authentication via windows command prompt

PowerShell solution

Using Posh-SSH:

New-SSHSession -ComputerName -Credential $cred | Out-Null
Invoke-SSHCommand -SessionId 1 -Command "nohup sleep 5 >> abs.log &" | Out-Null

How to change the Eclipse default workspace?

In Eclipse, go to File -> Switch Workspace, choose or create a new workspace.

Git: how to reverse-merge a commit?

To revert a merge commit, you need to use: git revert -m <parent number>. So for example, to revert the recent most merge commit using the parent with number 1 you would use:

git revert -m 1 HEAD

To revert a merge commit before the last commit, you would do:

git revert -m 1 HEAD^

Use git show <merge commit SHA1> to see the parents, the numbering is the order they appear e.g. Merge: e4c54b3 4725ad2

git merge documentation:

git merge discussion (confusing but very detailed):

What are ODEX files in Android?


According to the docs: an .odex file:

contains AOT compiled code for methods in the APK.

Furthermore, they appear to be regular shared libraries, since if you get any app, and check:

file /data/app/*/oat/arm64/base.odex

it says:

base.odex: ELF shared object, 64-bit LSB arm64, stripped

and aarch64-linux-gnu-objdump -d base.odex seems to work and give some meaningful disassembly (but also some rubbish sections).

display:inline vs display:block

Display : block will take the whole line i.e without line break

Display :inline will take only exact space that it requires.

   display : block;
   border:1px solid;

  display : inline;
  border:1px solid;

You can refer example in this fiddle

Get Android API level of phone currently running my application

try this :Float.valueOf(android.os.Build.VERSION.RELEASE) <= 2.1

Proper use of const for defining functions in JavaScript

It has been three years since this question was asked, but I am just now coming across it. Since this answer is so far down the stack, please allow me to repeat it:

Q: I am interested if there are any limits to what types of values can be set using const in JavaScript—in particular functions. Is this valid? Granted it does work, but is it considered bad practice for any reason?

I was motivated to do some research after observing one prolific JavaScript coder who always uses const statement for functions, even when there is no apparent reason/benefit.

In answer to "is it considered bad practice for any reason?" let me say, IMO, yes it is, or at least, there are advantages to using function statement.

It seems to me that this is largely a matter of preference and style. There are some good arguments presented above, but none so clear as is done in this article:

Constant confusion: why I still use JavaScript function statements by Sourour, JavaScript guru, consultant, and teacher.

I urge everyone to read that article, even if you have already made a decision.

Here's are the main points:

Function statements have two clear advantages over [const] function expressions:

Advantage #1: Clarity of intent

When scanning through thousands of lines of code a day, it’s useful to be able to figure out the programmer’s intent as quickly and easily as possible.

Advantage #2: Order of declaration == order of execution

Ideally, I want to declare my code more or less in the order that I expect it will get executed.

This is the showstopper for me: any value declared using the const keyword is inaccessible until execution reaches it.

What I’ve just described above forces us to write code that looks upside down. We have to start with the lowest level function and work our way up.

My brain doesn’t work that way. I want the context before the details.

Most code is written by humans. So it makes sense that most people’s order of understanding roughly follows most code’s order of execution.

What is cardinality in Databases?

In database, Cardinality number of rows in the table.

enter image description here img source

enter image description here img source

  • Relationships are named and classified by their cardinality (i.e. number of elements of the set).
  • Symbols which appears closes to the entity is Maximum cardinality and the other one is Minimum cardinality.
  • Entity relation, shows end of the relationship line as follows:
    enter image description here

enter image description here

image source

How to fix Array indexOf() in JavaScript for Internet Explorer browsers

With the Underscore.js

var arr=['a','a1','b'] _.filter(arr, function(a){ return a.indexOf('a') > -1; })

Make EditText ReadOnly

In XML use:


As an example:

    android:editable="false" />

Error: Address already in use while binding socket with address but the port number is shown free by `netstat`

As already said, your socket probably enter in TIME_WAIT state. This issue is well described by Thomas A. Fine here.

To summary, socket closing process follow diagram below:

Socket closing process

Thomas says:

Looking at the diagram above, it is clear that TIME_WAIT can be avoided if the remote end initiates the closure. So the server can avoid problems by letting the client close first. The application protocol must be designed so that the client knows when to close. The server can safely close in response to an EOF from the client, however it will also need to set a timeout when it is expecting an EOF in case the client has left the network ungracefully. In many cases simply waiting a few seconds before the server closes will be adequate.

Using SO_REUSEADDR is commonly suggested on internet, but Thomas add:

Oddly, using SO_REUSEADDR can actually lead to more difficult "address already in use" errors. SO_REUSADDR permits you to use a port that is stuck in TIME_WAIT, but you still can not use that port to establish a connection to the last place it connected to. What? Suppose I pick local port 1010, and connect to port 300, and then close locally, leaving that port in TIME_WAIT. I can reuse local port 1010 right away to connect to anywhere except for port 300.

Drag and drop menuitems

jQuery UI draggable and droppable are the two plugins I would use to achieve this effect. As for the insertion marker, I would investigate modifying the div (or container) element that was about to have content dropped into it. It should be possible to modify the border in some way or add a JavaScript/jQuery listener that listens for the hover (element about to be dropped) event and modifies the border or adds an image of the insertion marker in the right place.

How to Compare two Arrays are Equal using Javascript?

You could try this simple approach

var array1 = [4,8,9,10];_x000D_
var array2 = [4,8,9,10];_x000D_
if (array1.join('|') === array2.join('|')) {_x000D_
 console.log('The arrays are equal.');_x000D_
} else {_x000D_
 console.log('The arrays are NOT equal.');_x000D_
array1 = [[1,2],[3,4],[5,6],[7,8]];_x000D_
array2 = [[1,2],[3,4],[5,6],[7,8]];_x000D_
if (array1.join('|') === array2.join('|')) {_x000D_
 console.log('The arrays are equal.');_x000D_
} else {_x000D_
 console.log('The arrays are NOT equal.');_x000D_

If the position of the values are not important you could sort the arrays first.

if (array1.sort().join('|') === array2.sort().join('|')) {
    console.log('The arrays are equal.');
} else {
    console.log('The arrays are NOT equal.');

Websocket connections with Postman

You can use the tool APIC available here This tool allows you to test websocket which use either StompJS or native Websocket. More info here at

setAttribute('display','none') not working

It works for me

setAttribute('style', 'display:none');

C++ Redefinition Header Files (winsock2.h)

I ran into this problem when trying to pull a third party package which was apparently including windows.h somewhere in it's mess of headers. Defining _WINSOCKAPI_ at the project level was much easier (not to mention more maintainable) than wading through their soup and fixing the problematic include.

Stop an input field in a form from being submitted

You can write an event handler for onsubmit that removes the name attribute from all of the input fields that you want not to be included in the form submission.

Here's a quick untested example:

var noSubmitElements = [ 'someFormElementID1', 'someFormElementID2' ]; //...
function submitForm() {
    for( var i = 0, j = noSubmitElements.length; i < j; i++ ) {
form.onsubmit = submitForm;

referenced before assignment error in python

My Scenario

def example():
    cl = [0, 1]
    def inner():
        #cl = [1, 2] # access this way will throw `reference before assignment`
        cl[0] = 1 
        cl[1] = 2   # these won't


Send JSON via POST in C# and Receive the JSON returned?

Using the JSON.NET NuGet package and anonymous types, you can simplify what the other posters are suggesting:

// ...

string payload = JsonConvert.SerializeObject(new
    agent = new
        name    = "Agent Name",
        version = 1,

    username = "username",
    password = "password",
    token    = "xxxxx",

var client = new HttpClient();
var content = new StringContent(payload, Encoding.UTF8, "application/json");

HttpResponseMessage response = await client.PostAsync(uri, content);

// ...

HTML img tag: title attribute vs. alt attribute?

The ALT attribute is for the visually impaired user that would use a screen reader. If the ALT is missing from ANY image tag, the entire url for the image will be read. If the images are for part of the design of the site, they should still have the ALT but they can be left empty so the url doesn't have to be read for every part of the site.

Twitter Bootstrap Responsive Background-Image inside Div

The way to do this is by using background-size so in your case:

background-size: 50% 50%;


You can set the width and the height of the elements to percentages as well

How to get a list of images on docker registry v2

I wrote an easy-to-use command line tool for listing images in various ways (like list all images, list all tags of those images, list all layers of those tags).

It also allows you to delete unused images in various ways, like delete only older tags of a single image or from all images etc. This is convenient when you are filling your registry from a CI server and want to keep only latest/stable versions.

It is written in python and does not need you to download bulky big custom registry images.

How to convert HTML to PDF using iText

This links might be helpful to convert.

If it is a college Project, you can even go for these,

Example is given to convert HTML to PDF

How can I read comma separated values from a text file in Java?

You can also use the java.util.Scanner class.

private static void readFileWithScanner() {
    File file = new File("path/to/your/file/file.txt");

    Scanner scan = null;

    try {
        scan = new Scanner(file);

        while (scan.hasNextLine()) {
            String line = scan.nextLine();
            String[] lineArray = line.split(",");
            // do something with lineArray, such as instantiate an object
    } catch (FileNotFoundException e) {
    } finally {

How do I compare 2 rows from the same table (SQL Server)?

I had a situation where I needed to compare each row of a table with the next row to it, (next here is relative to my problem specification) in the example next row is specified using the order by clause inside the row_number() function.

so I wrote this:

DECLARE @T TABLE (col1 nvarchar(50));

insert into @T VALUES ('A'),('B'),('C'),('D'),('E')

select I1.col1 Instance_One_Col, I2.col1 Instance_Two_Col  from (
 select col1,row_number() over (order by col1) as row_num
) AS I1
left join (
 select col1,row_number() over (order by col1) as row_num
) AS I2 on I1.row_num = I2.row_num - 1

after that I can compare each row to the next one as I need

Set cookie and get cookie with JavaScript

These are much much better references than w3schools (the most awful web reference ever made):

Examples derived from these references:

// sets the cookie cookie1
document.cookie = 'cookie1=test; expires=Sun, 1 Jan 2023 00:00:00 UTC; path=/'

// sets the cookie cookie2 (cookie1 is *not* overwritten)
document.cookie = 'cookie2=test; expires=Sun, 1 Jan 2023 00:00:00 UTC; path=/'

// remove cookie2
document.cookie = 'cookie2=; expires=Thu, 01 Jan 1970 00:00:00 UTC; path=/'

The Mozilla reference even has a nice cookie library you can use.

How can I specify system properties in Tomcat configuration on startup?

This question is addressed in the Apache wiki.

Question: "Can I set Java system properties differently for each webapp?"

Answer: No. If you can edit Tomcat's startup scripts (or better create a file), you can add "-D" options to Java. But there is no way in Java to have different values of system properties for different classes in the same JVM. There are some other methods available, like using ServletContext.getContextPath() to get the context name of your web application and locate some resources accordingly, or to define elements in WEB-INF/web.xml file of your web application and then set the values for them in Tomcat context file (META-INF/context.xml). See .

How do I create a new line in Javascript?

If you are using a JavaScript file (.js) then use document.write("\n");. If you are in a html file (.html or . htm) then use document.write("<br/>");.

sql query to get earliest date

SELECT TOP 1 ID, Name, Score, [Date]
FROM myTable
Order BY [Date]

What is Mocking?

Other answers explain what mocking is. Let me walk you through it with different examples. And believe me, it's actually far more simpler than you think.

tl;dr It's an instance of the original class. It has other data injected into so you avoid testing the injected parts and solely focus on testing the implementation details of your class/functions.

Simple example:

class Foo {
    func add (num1: Int, num2: Int) -> Int { // Line A 
        return num1 + num2 // Line B

let unit = Foo() // unit under test

As you can see, I'm not testing LineA ie I'm not validating the input parameters. I'm not validating to see if num1, num2 are an Integer. I have no asserts against that.

I'm only testing to see if LineB (my implementation) given the mocked values 1 and 5 is doing as I expect.

Obviously in the real word this can become much more complex. The parameters can be a custom object like a Person, Address, or the implementation details can be more than a single +. But the logic of testing would be the same.

Non-coding Example:

Assume you're building a machine that identifies the type and brand name of electronic devices for an airport security. The machine does this by processing what it sees with its camera.

Now your manager walks in the door and asks you to unit-test it.

Then you as a developer you can either bring 1000 real objects, like a MacBook pro, Google Nexus, a banana, an iPad etc in front of it and test and see if it all works.

But you can also use mocked objects, like an identical looking MacBook pro (with no real internal parts) or a plastic banana in front of it. You can save yourself from investing in 1000 real laptops and rotting bananas.

The point is you're not trying to test if the banana is fake or not. Nor testing if the laptop is fake or not. All you're doing is testing if your machine once it sees a banana it would say not an electronic device and for a MacBook Pro it would say: Laptop, Apple. To the machine, the outcome of its detection should be the same for fake/mocked electronics and real electronics. If your machine also factored in the internals of a laptop (x-ray scan) or banana then your mocks' internals need to look the same as well. But you could also use a gadget with a friend motherboard. Had your machine tested whether or not devices can power on then well you'd need real devices.

The logic mentioned above applies to unit-testing of actual code as well. That is a function should work the same with real values you get from real input (and interactions) or mocked values you inject during unit-testing. And just as how you save yourself from using a real banana or MacBook, with unit-tests (and mocking) you save yourself from having to do something that causes your server to return a status code of 500, 403, 200, etc (forcing your server to trigger 500 is only when server is down, while 200 is when server is up. It gets difficult to run 100 network focused tests if you have to constantly wait 10 seconds between switching over server up and down). So instead you inject/mock a response with status code 500, 200, 403, etc and test your unit/function with a injected/mocked value.

Be aware:

Sometimes you don't correctly mock the actual object. Or you don't mock every possibility. E.g. your fake laptops are dark, and your machine accurately works with them, but then it doesn't work accurately with white fake laptops. Later when you ship this machine to customers they complain that it doesn't work all the time. You get random reports that it's not working. It takes you 3 months of time to finally figure out that the color of fake laptops need to be more varied so you can test your modules appropriately.

For a true coding example, your implementation may be different for status code 200 with image data returned vs 200 with image data not returned. For this reason it's good to use an IDE that provides code coverage e.g. the image below shows that your unit-tests don't ever go through the lines marked with brown.

enter image description here

image source

Real world coding Example:

Let's say you are writing an iOS application and have network calls.Your job is to test your application. To test/identify whether or not the network calls work as expected is NOT YOUR RESPONSIBILITY . It's another party's (server team) responsibility to test it. You must remove this (network) dependency and yet continue to test all your code that works around it.

A network call can return different status codes 404, 500, 200, 303, etc with a JSON response.

Your app is suppose to work for all of them (in case of errors, your app should throw its expected error). What you do with mocking is you create 'imaginary—similar to real' network responses (like a 200 code with a JSON file) and test your code without 'making the real network call and waiting for your network response'. You manually hardcode/return the network response for ALL kinds of network responses and see if your app is working as you expect. (you never assume/test a 200 with incorrect data, because that is not your responsibility, your responsibility is to test your app with a correct 200, or in case of a 400, 500, you test if your app throws the right error)

This creating imaginary—similar to real is known as mocking.

In order to do this, you can't use your original code (your original code doesn't have the pre-inserted responses, right?). You must add something to it, inject/insert that dummy data which isn't normally needed (or a part of your class).

So you create an instance the original class and add whatever (here being the network HTTPResponse, data OR in the case of failure, you pass the correct errorString, HTTPResponse) you need to it and then test the mocked class.

Long story short, mocking is to simplify and limit what you are testing and also make you feed what a class depends on. In this example you avoid testing the network calls themselves, and instead test whether or not your app works as you expect with the injected outputs/responses —— by mocking classes

Needless to say, you test each network response separately.

Now a question that I always had in my mind was: The contracts/end points and basically the JSON response of my APIs get updated constantly. How can I write unit tests which take this into consideration?

To elaborate more on this: let’s say model requires a key/field named username. You test this and your test passes. 2 weeks later backend changes the key's name to id. Your tests still passes. right? or not?

Is it the backend developer’s responsibility to update the mocks. Should it be part of our agreement that they provide updated mocks?

The answer to the above issue is that: unit tests + your development process as a client-side developer should/would catch outdated mocked response. If you ask me how? well the answer is:

Our actual app would fail (or not fail yet not have the desired behavior) without using updated APIs...hence if that fails...we will make changes on our development code. Which again leads to our tests failing....which we’ll have to correct it. (Actually if we are to do the TDD process correctly we are to not write any code about the field unless we write the test for it...and see it fail and then go and write the actual development code for it.)

This all means that backend doesn’t have to say: “hey we updated the mocks” eventually happens through your code development/debugging. ??Because it’s all part of the development process! Though if backend provides the mocked response for you then it's easier.

My whole point on this is that (if you can’t automate getting updated mocked API response then) some human interaction is required ie manual updates of JSONs and having short meetings to make sure their values are up to date will become part of your process

This section was written thanks to a slack discussion in our CocoaHead meetup group

For iOS devs only:

A very good example of mocking is this Practical Protocol-Oriented talk by Natasha Muraschev. Just skip to minute 18:30, though the slides may become out of sync with the actual video ???

I really like this part from the transcript:

Because this is testing...we do want to make sure that the get function from the Gettable is called, because it can return and the function could theoretically assign an array of food items from anywhere. We need to make sure that it is called;

nodejs send html file to client

Try your code like this:

var app = express();
app.get('/test', function(req, res) {
    res.sendFile('views/test.html', {root: __dirname })
  1. Use res.sendFile instead of reading the file manually so express can handle setting the content-type properly for you.

  2. You don't need the app.engine line, as that is handled internally by express.

Reading a plain text file in Java

The easiest way is to use the Scanner class in Java and the FileReader object. Simple example:

Scanner in = new Scanner(new FileReader("filename.txt"));

Scanner has several methods for reading in strings, numbers, etc... You can look for more information on this on the Java documentation page.

For example reading the whole content into a String:

StringBuilder sb = new StringBuilder();
while(in.hasNext()) {
outString = sb.toString();

Also if you need a specific encoding you can use this instead of FileReader:

new InputStreamReader(new FileInputStream(fileUtf8), StandardCharsets.UTF_8)