Programs & Examples On #Stub

A replacement implementation for objects, methods, or functions in order to remove external dependencies.

What's the difference between a mock & stub?

  • Stubs vs. Mocks
    • Stubs
      1. provide specific answers to methods calls
        • ex: myStubbedService.getValues() just return a String needed by the code under test
      2. used by code under test to isolate it
      3. cannot fail test
        • ex: myStubbedService.getValues() just returns the stubbed value
      4. often implement abstract methods
    • Mocks
      1. "superset" of stubs; can assert that certain methods are called
        • ex: verify that myMockedService.getValues() is called only once
      2. used to test behaviour of code under test
      3. can fail test
        • ex: verify that myMockedService.getValues() was called once; verification fails, because myMockedService.getValues() was not called by my tested code
      4. often mocks interfaces

What does "to stub" mean in programming?

A stub, in this context, means a mock implementation.

That is, a simple, fake implementation that conforms to the interface and is to be used for testing. :connection timed out: connect?

Number (1): The IP was incorrect - is the correct answer. The /etc/hosts file (a.k.a. C:\Windows\system32\drivers\etc\hosts ) had an incorrect entry for the local machine name. Corrected the 'hosts' file and Camel runs very well. Thanks for the pointer.

Access restriction on class due to restriction on required library rt.jar?

I have been getting this error too, but my project is built on the command line using Maven and the tycho compiler (it's a set of OSGi plugins). After masses of sifting through people having the same problem but fixing it in Eclipse rather than on the command line, I found a message on the Tycho developer forum that answered my question, using configuration in pom.xml to ignore the compiler warning about the access restriction:


More information can be found in the Tycho FAQ. This took me AGES to work out, so I figured I would assist anyone else trying to fix these access restriction errors from the command line by posting this answer.

How to programmatically send a 404 response with Express/Node?

IMO the nicest way is to use the next() function:

router.get('/', function(req, res, next) {
    var err = new Error('Not found');
    err.status = 404;
    return next(err);

Then the error is handled by your error handler and you can style the error nicely using HTML.

Setting up maven dependency for SQL Server

Even after installing the sqlserver jar, my maven was trying to fetch the dependecy from maven repository. I then, provided my pom the repository of my local machine and it works fine after that...might be of help for someone.


Equivalent of SQL ISNULL in LINQ?

You can use the ?? operator to set the default value but first you must set the Nullable property to true in your dbml file in the required field (xx.Online)

var hht = from x in db.HandheldAssets
        join a in db.HandheldDevInfos on x.AssetID equals a.DevName into DevInfo
        from aa in DevInfo.DefaultIfEmpty()
        select new
        AssetID = x.AssetID,
        Status = xx.Online ?? false

How to pass parameters in GET requests with jQuery

Put your params in the data part of the ajax call. See the docs. Like so:

    url: "/TestPage.aspx",
    data: {"first": "Manu","Last":"Sharma"},
    success: function(response) {
        //Do Something
    error: function(xhr) {
        //Do Something to handle error

Web Service vs WCF Service

This answer is based on an article that no longer exists:

Summary of article:

"Basically, WCF is a service layer that allows you to build applications that can communicate using a variety of communication mechanisms. With it, you can communicate using Peer to Peer, Named Pipes, Web Services and so on.

You can’t compare them because WCF is a framework for building interoperable applications. If you like, you can think of it as a SOA enabler. What does this mean?

Well, WCF conforms to something known as ABC, where A is the address of the service that you want to communicate with, B stands for the binding and C stands for the contract. This is important because it is possible to change the binding without necessarily changing the code. The contract is much more powerful because it forces the separation of the contract from the implementation. This means that the contract is defined in an interface, and there is a concrete implementation which is bound to by the consumer using the same idea of the contract. The datamodel is abstracted out."

... later ...

"should use WCF when we need to communicate with other communication technologies (e,.g. Peer to Peer, Named Pipes) rather than Web Service"

Check if object value exists within a Javascript array of objects and if not add a new object to array

try this

first method using some

  let arr = [{ id: 1, username: 'fred' }, { id: 2, username: 'bill' }, { id: 3, username: 'ted' }];
    let found = arr.some(ele => ele.username === 'bill');

second method using includes, map

   let arr = [{ id: 1, username: 'fred' }, { id: 2, username: 'bill' }, { id: 3, username: 'ted' }];
    let mapped = => ele.username);
    let found = mapped.includes('bill');

How to get the list of all database users

Whenever you 'see' something in the GUI (SSMS) and you're like "that's what I need", you can always run Sql Profiler to fish for the query that was used.

Run Sql Profiler. Attach it to your database of course.

Then right click in the GUI (in SSMS) and click "Refresh".
And then go see what Profiler "catches".

I got the below when I was in MyDatabase / Security / Users and clicked "refresh" on the "Users".

Again, I didn't come up with the WHERE clause and the LEFT OUTER JOIN, it was a part of the SSMS query. And this query is something that somebody at Microsoft has written (you know, the peeps who know the product inside and out, aka, the experts), so they are familiar with all the weird "flags" in the database.

But the SSMS/GUI -> Sql Profiler tricks works in many scenarios.

'Server[@Name=' + quotename(CAST(
       AS sysname),'''') + ']' + '/Database[@Name=' + quotename(db_name(),'''') + ']' + '/User[@Name=' + quotename(,'''') + ']' AS [Urn],
u.create_date AS [CreateDate],
u.principal_id AS [ID],
CAST(CASE dp.state WHEN N'G' THEN 1 WHEN 'W' THEN 1 ELSE 0 END AS bit) AS [HasDBAccess]
sys.database_principals AS u
LEFT OUTER JOIN sys.database_permissions AS dp ON dp.grantee_principal_id = u.principal_id and dp.type = 'CO'
(u.type in ('U', 'S', 'G', 'C', 'K' ,'E', 'X'))
[Name] ASC

Why is datetime.strptime not working in this simple example?

You should be using datetime.datetime.strptime. Note that very old versions of Python (2.4 and older) don't have datetime.datetime.strptime; use time.strptime in that case.

How to restart Jenkins manually?

For restarting Jenkins manually using the browser:

Enter your www.jenkins-ip/restart (for example, http://localhost:8080/restart) in the browser. Jenkins will restart and load the login page automatically after restart.

How to get POSTed JSON in Flask?

For all those whose issue was from the ajax call, here is a full example :

Ajax call : the key here is to use a dict and then JSON.stringify

    var dict = {username : "username" , password:"password"};

        type: "POST", 
        url: "", //localhost Flask
        data : JSON.stringify(dict),
        contentType: "application/json",

And on server side :

from flask import Flask
from flask import request
import json

app = Flask(__name__)

@app.route("/",  methods = ['POST'])
def hello():
    return json.dumps({'success':True}), 200, {'ContentType':'application/json'} 

if __name__ == "__main__":

URL Encode a string in jQuery for an AJAX request

I'm using MVC3/EntityFramework as back-end, the front-end consumes all of my project controllers via jquery, posting directly (using $.post) doesnt requires the data encription, when you pass params directly other than URL hardcoded. I already tested several chars i even sent an URL(this one as a parameter and had no issue at all even though encodeURIComponent works great when you pass all data in within the URL (hardcoded)

Hardcoded URL i.e.>

 var encodedName = encodeURIComponent(name);
 var url = "ControllerName/ActionName/" + encodedName + "/" + keyword + "/" + description + "/" + linkUrl + "/" + includeMetrics + "/" + typeTask + "/" + project + "/" + userCreated + "/" + userModified + "/" + status + "/" + parent;; // + name + "/" + keyword + "/" + description + "/" + linkUrl + "/" + includeMetrics + "/" + typeTask + "/" + project + "/" + userCreated + "/" + userModified + "/" + status + "/" + parent;

Otherwise dont use encodeURIComponent and instead try passing params in within the ajax post method

 var url = "ControllerName/ActionName/";   
        { name: nameVal, fkKeyword: keyword, description: descriptionVal, linkUrl: linkUrlVal, includeMetrics: includeMetricsVal, FKTypeTask: typeTask, FKProject: project, FKUserCreated: userCreated, FKUserModified: userModified, FKStatus: status, FKParent: parent },
 function (data) {.......});

Text inset for UITextField?

In a class derived from UITextField, override at least this two methods:

- (CGRect)textRectForBounds:(CGRect)bounds;
- (CGRect)editingRectForBounds:(CGRect)bounds;

It might be as simple as this if you have no additional content:

return CGRectInset(bounds , 10, 10);

UITextField provides several positioning methods you can override.

Unexpected end of file error

The line #include "stdafx.h" must be the first line at the top of each source file, before any other header files are included.

If what you've shown is the entire .cxx file, then you did forget to include stdafx.h in that file. Connection refused

I had same problem and the problem was that I was not closing socket object.After using socket.close(); problem solved. This code works for me.

public class ClientDemo {
    public static void main(String[] args) throws UnknownHostException,
            IOException {
        Socket socket = new Socket("", 55286);
        OutputStreamWriter os = new OutputStreamWriter(socket.getOutputStream());
        os.write("Santosh Karna");


public class ServerDemo {
    public static void main(String[] args) throws IOException {
        System.out.println("server is started");
        ServerSocket serverSocket= new ServerSocket(55286);
        System.out.println("server is waiting");
        Socket socket=serverSocket.accept();
        System.out.println("Client connected");
        BufferedReader reader=new BufferedReader(new InputStreamReader(socket.getInputStream()));
        String str=reader.readLine();
        System.out.println("Client data: "+str);


How can I delay a method call for 1 second?

You could also use a block

dispatch_after(dispatch_time(DISPATCH_TIME_NOW, 1 * NSEC_PER_SEC), dispatch_get_main_queue(), ^{
    [object method]; 

Most of time you will want to use dispatch_get_main_queue, although if there is no UI in the method you could use a global queue.


Swift 3 version:

DispatchQueue.main.asyncAfter(deadline: .now() + 1) {

Equally, might also be a good option.

"Couldn't read dependencies" error with npm

This doesn't look like your issue, but for the sake of others, for me this was caused by an invalid version number in package.json (had to change 2.4 to 2.4.0).

Creating a class object in c++

Example example;

Here example is an object on the stack.

Example* example=new Example();

This could be broken into:

Example* example;
example=new Example();

Here the first statement creates a variable example which is a "pointer to Example". When the constructor is called, memory is allocated for it on the heap (dynamic allocation). It is the programmer's responsibility to free this memory when it is no longer needed. (C++ does not have garbage collection like java).

The type or namespace cannot be found (are you missing a using directive or an assembly reference?)

I get this error when my project .net framework version does not match the framework version of the DLL I am linking to. In my case, I was getting:

"The type or namespace name 'UserVoice' could not be found (are you missing a using directive or an assembly reference?).

UserVoice was .Net 4.0, and my project properties were set to ".Net 4.0 Client Profile". Changing to .Net 4.0 on the project cleared the error. I hope this helps someone.

Can a PDF file's print dialog be opened with Javascript?

If you are using the prawn gem for Ruby on Rails to generate your PDF, you can use the following additional gem to active the print dialog:


Linq Syntax - Selecting multiple columns

As the other answers have indicated, you need to use an anonymous type.

As far as syntax is concerned, I personally far prefer method chaining. The method chaining equivalent would be:-

var employee = _db.EMPLOYEEs
    .Where(x => x.EMAIL == givenInfo || x.USER_NAME == givenInfo)
    .Select(x => new { x.EMAIL, x.ID });

AFAIK, the declarative LINQ syntax is converted to a method call chain similar to this when it is compiled.


If you want the entire object, then you just have to omit the call to Select(), i.e.

var employee = _db.EMPLOYEEs
    .Where(x => x.EMAIL == givenInfo || x.USER_NAME == givenInfo);

Lua String replace


name = "^aH^ai"
name = name:gsub("%^a", "")

See also:

Dynamic instantiation from string name of a class in dynamically imported module?

Copy-paste snippet:

import importlib
def str_to_class(module_name, class_name):
    """Return a class instance from a string reference"""
        module_ = importlib.import_module(module_name)
            class_ = getattr(module_, class_name)()
        except AttributeError:
            logging.error('Class does not exist')
    except ImportError:
        logging.error('Module does not exist')
    return class_ or None

jquery simple image slideshow tutorial

Here is my adaptation of Michael Soriano's tutorial. See below or in JSBin.

$(function() {_x000D_
  var theImage = $('ul#ss li img');_x000D_
  var theWidth = theImage.width();_x000D_
  //wrap into mother div_x000D_
  $('ul#ss').wrap('<div id="mother" />');_x000D_
  //assign height width and overflow hidden to mother_x000D_
    width: function() {_x000D_
      return theWidth;_x000D_
    height: function() {_x000D_
      return theImage.height();_x000D_
    position: 'relative',_x000D_
    overflow: 'hidden'_x000D_
  //get total of image sizes and set as width for ul _x000D_
  var totalWidth = theImage.length * theWidth;_x000D_
    width: function() {_x000D_
      return totalWidth;_x000D_
  var ss_timer = setInterval(function() {_x000D_
  }, 3000);_x000D_
  function ss_next() {_x000D_
    var a = $(".active");_x000D_
    if (a.hasClass('last')) {_x000D_
      //last element -- loop_x000D_
        "margin-left": (0)_x000D_
      }, 1000);_x000D_
    } else {_x000D_
        "margin-left": (-(a.index() + 1) * theWidth)_x000D_
      }, 1000);_x000D_'active');_x000D_
  // Cancel slideshow and move next manually on click_x000D_
  $('ul#ss li img').on('click', function() {_x000D_
* {_x000D_
  margin: 0;_x000D_
  padding: 0;_x000D_
#ss {_x000D_
  list-style: none;_x000D_
#ss li {_x000D_
  float: left;_x000D_
#ss img {_x000D_
  width: 200px;_x000D_
  height: 100px;_x000D_
<script src=""></script>_x000D_
<ul id="ss">_x000D_
  <li class="active">_x000D_
    <img src="">_x000D_
    <img src="">_x000D_
  <li class="last">_x000D_
    <img src="">_x000D_

How to open a new form from another form

ok so I used this:

public partial class Form1 : Form
    private void Button_Click(object sender, EventArgs e)
        Form2 myForm = new Form2();

This seems to be working fine but the first form is just hidden and it can still generate events. the "this.Close()" is needed to close the first form but if you still want your form to run (and not act like a launcher) you MUST replace it with


Best of luck!

Python argparse command line flags without arguments

Adding a quick snippet to have it ready to execute:


import argparse
parser = argparse.ArgumentParser(description="Flip a switch by setting a flag")
parser.add_argument('-w', action='store_true')

args = parser.parse_args()
print args.w


python -w
>> True

Remove a HTML tag but keep the innerHtml


This selects all <b> elements, then uses .contents() to target the text content of the <b>, then .unwrap() to remove its parent <b> element.

For the greatest performance, always go native:

var b = document.getElementsByTagName('b');

while(b.length) {
    var parent = b[ 0 ].parentNode;
    while( b[ 0 ].firstChild ) {
        parent.insertBefore(  b[ 0 ].firstChild, b[ 0 ] );
     parent.removeChild( b[ 0 ] );

This will be much faster than any jQuery solution provided here.

What's the difference between a Python module and a Python package?

First, keep in mind that, in its precise definition, a module is an object in the memory of a Python interpreter, often created by reading one or more files from disk. While we may informally call a disk file such as a/b/ a "module," it doesn't actually become one until it's combined with information from several other sources (such as sys.path) to create the module object.

(Note, for example, that two modules with different names can be loaded from the same file, depending on sys.path and other settings. This is exactly what happens with python -m my.module followed by an import my.module in the interpreter; there will be two module objects, __main__ and my.module, both created from the same file on disk, my/

A package is a module that may have submodules (including subpackages). Not all modules can do this. As an example, create a small module hierarchy:

$ mkdir -p a/b
$ touch a/b/

Ensure that there are no other files under a. Start a Python 3.4 or later interpreter (e.g., with python3 -i) and examine the results of the following statements:

import a
a                ? <module 'a' (namespace)>
a.b              ? AttributeError: module 'a' has no attribute 'b'
import a.b.c
a.b              ? <module 'a.b' (namespace)>
a.b.c            ? <module 'a.b.c' from '/home/cjs/a/b/'>

Modules a and a.b are packages (in fact, a certain kind of package called a "namespace package," though we wont' worry about that here). However, module a.b.c is not a package. We can demonstrate this by adding another file, a/ to the directory structure above and starting a fresh interpreter:

import a.b.c
? ImportError: No module named 'a.b.c'; 'a.b' is not a package
import a.b
a                ? <module 'a' (namespace)>
a.__path__       ? _NamespacePath(['/.../a'])
a.b              ? <module 'a.b' from '/home/cjs/tmp/a/'>
a.b.__path__     ? AttributeError: 'module' object has no attribute '__path__'

Python ensures that all parent modules are loaded before a child module is loaded. Above it finds that a/ is a directory, and so creates a namespace package a, and that a/ is a Python source file which it loads and uses to create a (non-package) module a.b. At this point you cannot have a module a.b.c because a.b is not a package, and thus cannot have submodules.

You can also see here that the package module a has a __path__ attribute (packages must have this) but the non-package module a.b does not.

Fastest way to determine if record exists

Nothing can beat -

SELECT TOP 1 1 FROM products WHERE id = 'some value';

You don't need to count to know if there is a data in table. And don't use alias when not necessary.

How to convert a Bitmap to Drawable in android?

Having seen a large amount of issues with bitmaps incorrectly scaling when converted to a BitmapDrawable, the general way to convert should be:

Drawable d = new BitmapDrawable(getResources(), bitmap);

Without the Resources reference, the bitmap may not render properly, even when scaled correctly. There are numerous questions on here which would be solved simply by using this method rather than a straight call with only the bitmap argument.

wget can't download - 404 error

I had the same problem. Solved using single quotes like this:

$ wget ''

wget version in use:

$ wget --version
GNU Wget 1.11.4 Red Hat modified

Sending event when AngularJS finished loading

According to the Angular team and this Github issue:

we now have $viewContentLoaded and $includeContentLoaded events that are emitted in ng-view and ng-include respectively. I think this is as close as one can get to knowing when we are done with the compilation.

Based on this, it seems this is currently not possible to do in a reliable way, otherwise Angular would have provided the event out of the box.

Bootstrapping the app implies running the digest cycle on the root scope, and there is also not a digest cycle finished event.

According to the Angular 2 design docs:

Because of multiple digests, it is impossible to determine and notify the component that the model is stable. This is because notification can further change data, which can restart the binding process.

According to this, the fact that this is not possible is one the reasons why the decision was taken to go for a rewrite in Angular 2.

How can I use Html.Action?

You should look at the documentation for the Action method; it's explained well. For your case, this should work:

@Html.Action("GetOptions", new { pk="00", rk="00" });

The controllerName parameter will default to the controller from which Html.Action is being invoked. So if you're trying to invoke an action from another controller, you'll have to specify the controller name like so:

@Html.Action("GetOptions", "ControllerName", new { pk="00", rk="00" });

AngularJS : ng-model binding not updating when changed with jQuery

Whatever happens outside the Scope of Angular, Angular will never know that.

Digest cycle put the changes from the model -> controller and then from controller -> model.

If you need to see the latest Model, you need to trigger the digest cycle

But there is a chance of a digest cycle in progress, so we need to check and init the cycle.

Preferably, always perform a safe apply.

       $scope.safeApply = function(fn) {
            if (this.$root) {
                var phase = this.$root.$$phase;
                if (phase == '$apply' || phase == '$digest') {
                    if (fn && (typeof (fn) === 'function')) {
                } else {

          // your function here.

Hibernate: "Field 'id' doesn't have a default value"

Take a look at GeneratedValue's strategy. It typically looks something like:


Why extend the Android Application class?

I see that this question is missing an answer. I extend Application because I use Bill Pugh Singleton implementation (see reference) and some of my singletons need context. The Application class looks like this:

public class MyApplication extends Application {

    private static final String TAG = MyApplication.class.getSimpleName();

    private static MyApplication sInstance;

    @Contract(pure = true)
    public static Context getAppContext() {
        return sInstance;

    public void onCreate() {
        Log.d(TAG, "onCreate() called");
        sInstance = this;

And the singletons look like this:

public class DataManager {

    private static final String TAG = DataManager.class.getSimpleName();

    @Contract(pure = true)
    public static DataManager getInstance() {
        return InstanceHolder.INSTANCE;

    private DataManager() {

    private static final class InstanceHolder {
        private static final DataManager INSTANCE = new DataManager();

This way I don't need to have a context every time I'm using a singleton and get lazy synchronized initialization with minimal amount of code.

Tip: updating Android Studio singleton template saves a lot of time.

Listing files in a directory matching a pattern in Java

Since Java 8 you can use lambdas and achieve shorter code:

File dir = new File(xmlFilesDirectory);
File[] files = dir.listFiles((d, name) -> name.endsWith(".xml"));

Android button background color

Just use a MaterialButton and the app:backgroundTint attribute:


enter image description here

Why fragments, and when to use fragments instead of activities?

Activities are the full screen components in the app with the toolbar, everything else are preferably Fragments. One full screen parent activity with a toolbar can have multiple panes, scrollable pages, dialogs, etc. (all fragments), all of which can be accessed from the parent and communicate via the parent.


Activity A, Activity B, Activity C:

  • All activities need to have same code repeated, to show a basic toolbar for example, or inherit from a parent activity (becomes cumbersome to manage).
  • To move from one activity to the other, either all of them need to be in memory (overhead) or one needs to be destroyed for the other to open.
  • Communication between activities can be done via Intents.


Activity A, Fragment 1, Fragment 2, Fragment 3:

  • No code repetition, all screens have toolbars etc. from that one activity.
  • Several ways to move from one fragment to next - view pager, multi pane etc.
  • Activity has most data, so minimal inter-fragment communication needed. If still necessary, can be done via interfaces easily.
  • Fragments do not need to be full screen, lots of flexibility in designing them.
  • Fragments do not need to inflate layout if views are not necessary.
  • Several activities can use the same fragment.

What's the difference between "&nbsp;" and " "?

&nbsp; should be handled as a whitespace.

&nbsp;&nbsp; should be handled as two whitespaces

' ' can be handled as a non interesting whitespace

' ' + ' ' can be handled as a single ' '

How to check "hasRole" in Java Code with Spring Security?

You can get some help from AuthorityUtils class. Checking role as a one-liner:

if (AuthorityUtils.authorityListToSet(SecurityContextHolder.getContext().getAuthentication().getAuthorities()).contains("ROLE_MANAGER")) {
    /* ... */

Caveat: This does not check role hierarchy, if such exists.

Difference between HashMap and Map in Java..?

Map is an interface in Java. And HashMap is an implementation of that interface (i.e. provides all of the methods specified in the interface).

How do I remove the "extended attributes" on a file in Mac OS X?

Use the xattr command. You can inspect the extended attributes:

$ xattr s.7z

and use the -d option to delete one extended attribute:

$ xattr -d s.7z
$ xattr s.7z

you can also use the -c option to remove all extended attributes:

$ xattr -c s.7z
$ xattr s.7z

xattr -h will show you the command line options, and xattr has a man page.

What is /var/www/html?

In the most shared hosts you can't set it.

On a VPS or dedicated server, you can set it, but everything has its price.

On shared hosts, in general you receive a Linux account, something such as /home/(your username)/, and the equivalent of /var/www/html turns to /home/(your username)/public_html/ (or something similar, such as /home/(your username)/www)

If you're accessing your account via FTP, you automatically has accessing the your */home/(your username)/ folder, just find the www or public_html and put your site in it.

If you're using absolute path in the code, bad news, you need to refactor it to use relative paths in the code, at least in a shared host.

Returning a value even if no result

if you want both always a return value but never a null value you can combine count with coalesce :

select count(field1), coalesce(field1,'any_other_default_value') from table;

that because count, will force mysql to always return a value (0 if there is no values to count) and coalesce will force mysql to always put a value that is not null

IF statement: how to leave cell blank if condition is false ("" does not work)

Try this instead


This will return true for cells that are either truly blank, or contain nothing but white space.

See this post for a few other options.


To reflect the comments and what you ended up doing: Instead of evaluating to "" enter another value such as 'deleteme' and then search for 'deleteme' instead of blanks.


Converting a Java Keystore into PEM Format

I found a very interesting solution:

Then, I divided the pair public/private key into two files private.key publi.pem and it works!

Split string into array of characters?

Here's another way to do it in VBA.

Function ConvertToArray(ByVal value As String)
    value = StrConv(value, vbUnicode)
    ConvertToArray = Split(Left(value, Len(value) - 1), vbNullChar)
End Function
Sub example()
    Dim originalString As String
    originalString = "hi there"
    Dim myArray() As String
    myArray = ConvertToArray(originalString)
End Sub

Creating a procedure in mySql with parameters

I figured it out now. Here's the correct answer

   brugernavn1 varchar(64),
   password varchar(64)
   SELECT COUNT(*) FROM bruger 
   WHERE bruger.brugernavn=brugernavn1 
   AND bruger.pass=password; 

@ points to a global var in mysql. The above syntax is correct.

json.dumps vs flask.jsonify

The jsonify() function in flask returns a flask.Response() object that already has the appropriate content-type header 'application/json' for use with json responses. Whereas, the json.dumps() method will just return an encoded string, which would require manually adding the MIME type header.

See more about the jsonify() function here for full reference.

Edit: Also, I've noticed that jsonify() handles kwargs or dictionaries, while json.dumps() additionally supports lists and others.

How to get the Mongo database specified in connection string in C#

The answer below is apparently obsolete now, but works with older drivers. See comments.

If you have the connection string you could also use MongoDatabase directly:

var db =  MongoDatabase.Create(connectionString);
var coll = db.GetCollection("MyCollection");

How to install latest version of Node using Brew

Sometimes brew update fails on me because one package doesn't download properly. So you can just upgrade a specific library like this:

brew upgrade node

Concatenate text files with Windows command line, dropping leading lines

The help for copy explains that wildcards can be used to concatenate multiple files into one.

For example, to copy all .txt files in the current folder that start with "abc" into a single file named xyz.txt:

copy abc*.txt xyz.txt

ORA-06508: PL/SQL: could not find program unit being called

seems like opening a new session is the key.

see this answer.

and here is an awesome explanation about this error

Can I write or modify data on an RFID tag?

RFID Standards:

  • 125 Khz (low-frequency) tags are write-once/read-many, and usually only contain a small (permanent) unique identification number.

  • 13.56 Mhz (high-frequency) tags are usually read/write, they can typically store about 1 to 2 kilbytes of data in addition to their preset (permanent) unique ID number.

  • 860-960 Mhz (ultra-high-frequency) tags are typically read/write and can have much larger information storage capacity (I think that 64 KB is the highest currently available for passive tags) in addition to their preset (permanent) unique ID number.

More Information

Most read/write tags can be locked to prevent further writing to specific data-blocks in the tag's internal memory, while leaving other blocks unlocked. Different tag manufacturers make their tags differently, though.

Depending on your intended application, you might have to program your own microcontroller to interface with an embedded RFID read/write module using a manufacturer-specific protocol. That's certainly a lot cheaper than buying a complete RFID read/write unit, as they can cost several thousand dollars. With a custom solution, you can build you own unit that does specifically what you want for as little as $200.


RFID Journal

RFID Toys (Book) Website

SkyTek - RFID reader manufacturing company (you can buy their products through third-party retailers & wholesalers like Mouser)

Trossen Robotics - You can buy RFID tags and readers (125 Khz & 13.56 Mhz) from here, among other things

How To Include CSS and jQuery in my WordPress plugin?

Just to append to @pixeline's answer (tried to add a simple comment but the site said I needed 50 reputation).

If you are writing your plugin for the admin section then you should use:

add_action('admin_enqueue_scripts', "add_my_css_and_my_js_files");

The admin_enqueueu_scripts is the correct hook for the admin section, use wp_enqueue_scripts for the front end.

javascript create empty array of a given size

In 2018 and thenceforth we shall use [...Array(500)] to that end.

Convert comma separated string to array in PL/SQL

Using a pipelined table function:

  2  AS
  3    TABLE OF VARCHAR2(100)
  4  /

Type created.

  2      p_list IN VARCHAR2)
  3    RETURN test_type PIPELINED
  4  AS
  5    l_string LONG := p_list || ',';
  6    l_comma_index PLS_INTEGER;
  7    l_index PLS_INTEGER := 1;
  8  BEGIN
  9    LOOP
 10      l_comma_index := INSTR(l_string, ',', l_index);
 11      EXIT
 12    WHEN l_comma_index = 0;
 13      PIPE ROW ( TRIM(SUBSTR(l_string, l_index, l_comma_index - l_index)));
 14      l_index := l_comma_index                                + 1;
 15    END LOOP;
 16  RETURN;
 17  END comma_to_table;
 18  /

Function created.

Let's see the output:

  2  FROM TABLE(comma_to_table('12 3,456,,,,,abc,def'))
  3  /

12 3


8 rows selected.


Python NLTK: SyntaxError: Non-ASCII character '\xc3' in file (Sentiment Analysis -NLP)

Add the following to the top of your file # coding=utf-8

If you go to the link in the error you can seen the reason why:

Defining the Encoding

Python will default to ASCII as standard encoding if no other encoding hints are given. To define a source code encoding, a magic comment must be placed into the source files either as first or second line in the file, such as: # coding=

cannot download, $GOPATH not set

I am using vim to edit my .bashrc file but you code use a gui editor such as gedit.


Kindly subsitute /path/to/golang/projects below with your actual path location where you will store your golang projects.

Open .bashrc file in vim that is vim ~/.bashrc. Then add below lines at the end of the file.

# Setup Golang Development Environment ::
export GOROOT=/usr/local/go
export PATH=$PATH:$GOROOT/bin
# Third party go libraries will live under "~/golib" directory
export GOPATH="$HOME/golib"
export PATH="$PATH:$GOPATH/bin"
# Where your golang project code lives
export GOPATH=$GOPATH:/path/to/golang/projects

Save the file and type source ~/.bashrc to refresh your terminal session. Now try getting a package e.g. go get and check your ~/golib/bin directory it should have fresh package in it.

Navigate to your /path/to/golang/projects and create three folders in there i.e. bin,src and pkg

Now place your project folder inside /path/to/golang/projects/src e.g. /path/to/golang/projects/src/myfancygolangprojectand you should be good to go. Put all your golang codebase in there mate.

Exists Angularjs code/naming conventions?

I started this gist a year ago:

Brian Ford (member of the core team) has written this blog post about it:

And then we started with this component spec (which is not quite complete):

Since the last ng-conf there's this document for best practices by the core team:

Set initial focus in an Android application

@Someone Somewhere, I tried all of the above to no avail. The fix I found is from . Basically, you need to create an invisible layout just above the problematic Button:

<LinearLayout android:focusable="true"
              android:layout_height="0px" >
    <requestFocus />

Increment counter with loop

You can use varStatus in your c:forEach loop

In your first example you can get the counter to work properly as follows...

<c:forEach var="tableEntity" items='${requestScope.tables}'>
   <c:forEach var="rowEntity" items='${tableEntity.rows}' varStatus="count">            
        my count is ${count.count}

How to force garbage collector to run?


from MDSN,

Use this method to try to reclaim all memory that is inaccessible.

All objects, regardless of how long they have been in memory, are considered for collection; however, objects that are referenced in managed code are not collected. Use this method to force the system to try to reclaim the maximum amount of available memory.

Playing mp3 song on python

A simple solution:

import webbrowser"C:\Users\Public\Music\Sample Music\Kalimba.mp3")


Eclipse: All my projects disappeared from Project Explorer

Go to

File --> Import --> General --> Existing Project into Workspace

Then, In Root Directory Enter the workspace path where all your projects saved & click refresh as below

enter image description here

And Click Finish

enter image description here

Convert varchar to float IF ISNUMERIC

..extending Mikaels' answers

  • Two data types requires two columns
  • Adding e0 fixes some ISNUMERIC issues (such as + - . and empty string being accepted)

Which is the best IDE for Python For Windows

U can use eclipse. but u need to download pydev addon for that.

Reset all the items in a form

Do as below create class and call it like this

Check : Reset all Controls (Textbox, ComboBox, CheckBox, ListBox) in a Windows Form using C#

private void button1_Click(object sender, EventArgs e)

public class Utilities
        public static void ResetAllControls(Control form)
            foreach (Control control in form.Controls)
                if (control is TextBox)
                    TextBox textBox = (TextBox)control;
                    textBox.Text = null;

                if (control is ComboBox)
                    ComboBox comboBox = (ComboBox)control;
                    if (comboBox.Items.Count > 0)
                        comboBox.SelectedIndex = 0;

                if (control is CheckBox)
                    CheckBox checkBox = (CheckBox)control;
                    checkBox.Checked = false;

                if (control is ListBox)
                    ListBox listBox = (ListBox)control;

How to query a MS-Access Table from MS-Excel (2010) using VBA

The Provider piece must be Provider=Microsoft.ACE.OLEDB.12.0 if your target database is ACCDB format. Provider=Microsoft.Jet.OLEDB.4.0 only works for the older MDB format.

You shouldn't even need Access installed if you're running 32 bit Windows. Jet 4 is included as part of the operating system. If you're using 64 bit Windows, Jet 4 is not included, but you still wouldn't need Access itself installed. You can install the Microsoft Access Database Engine 2010 Redistributable. Make sure to download the matching version (AccessDatabaseEngine.exe for 32 bit Windows, or AccessDatabaseEngine_x64.exe for 64 bit).

You can avoid the issue about which ADO version reference by using late binding, which doesn't require any reference.

Dim conn As Object
Set conn = CreateObject("ADODB.Connection")

Then assign your ConnectionString property to the conn object. Here is a quick example which runs from a code module in Excel 2003 and displays a message box with the row count for MyTable. It uses late binding for the ADO connection and recordset objects, so doesn't require setting a reference.

Public Sub foo()
    Dim cn As Object
    Dim rs As Object
    Dim strSql As String
    Dim strConnection As String
    Set cn = CreateObject("ADODB.Connection")
    strConnection = "Provider=Microsoft.Jet.OLEDB.4.0;" & _
        "Data Source=C:\Access\webforums\whiteboard2003.mdb"
    strSql = "SELECT Count(*) FROM MyTable;"
    cn.Open strConnection
    Set rs = cn.Execute(strSql)
    MsgBox rs.fields(0) & " rows in MyTable"
    Set rs = Nothing
    Set cn = Nothing
End Sub

If this answer doesn't resolve the problem, edit your question to show us the full connection string you're trying to use and the exact error message you get in response for that connection string.

npm install vs. update - what's the difference?

npm update: install and update with latest node modules which are in package.json

npm install: install node modules which are defined in package.json(without update)

How to check whether Kafka Server is running?

I used the AdminClient api.

Properties properties = new Properties();
properties.put("bootstrap.servers", "localhost:9092");
properties.put("", 10000);
properties.put("", 5000);
try (AdminClient client = KafkaAdminClient.create(properties))
    ListTopicsResult topics = client.listTopics();
    Set<String> names = topics.names().get();
    if (names.isEmpty())
        // case: if no topic found.
    return true;
catch (InterruptedException | ExecutionException e)
    // Kafka is not available

ESLint - "window" is not defined. How to allow global variables in package.json

There is a builtin environment: browser that includes window.

Example .eslintrc.json:

"env": {
    "browser": true,
    "node": true,
    "jasmine": true

More information:

Also see the package.json answer by chevin99 below.

What is the best way to compare 2 folder trees on windows?

SyncToy is a free application from Microsoft with a "Preview" mode for comparing two paths. For example:

SyncToy Preview screenshot (source:

You can then choose one of three modes ("Synchronize", "Echo" and "Contribute") to resolve the differences.

Lastly, it comes with SyncToyCmd for creating and synchronizing folder pairs from the CLI or a Scheduled Task.

How to open a page in a new window or tab from code-behind

You can use scriptmanager.registerstartupscript to call a JavaScript function.

Inside that function, you can open a new window.

How to view file history in Git?

you could also use tig for a nice, ncurses-based git repository browser. To view history of a file:

tig path/to/file

What Are The Best Width Ranges for Media Queries

best bet is targeting features not devices unless you have to, bootstrap do well and you can extend on their breakpoints, for instance targeting pixel density and larger screens above 1920

Connection attempt failed with "ECONNREFUSED - Connection refused by server"

Use port number 22 (for sftp) instead of 21 (normal ftp). Solved this problem for me. get file names in directory?


could help

Get all Attributes from a HTML element with Javascript/jQuery

Setter and Getter!

(function($) {
    // Attrs
    $.fn.attrs = function(attrs) {
        var t = $(this);
        if (attrs) {
            // Set attributes
            t.each(function(i, e) {
                var j = $(e);
                for (var attr in attrs) {
                    j.attr(attr, attrs[attr]);
            return t;
        } else {
            // Get attributes
            var a = {},
                r = t.get(0);
            if (r) {
                r = r.attributes;
                for (var i in r) {
                    var p = r[i];
                    if (typeof p.nodeValue !== 'undefined') a[p.nodeName] = p.nodeValue;
            return a;


// Setter
    'name' : 'newName',
    'id' : 'newId',
    'readonly': true

// Getter
var attrs = $('#element').attrs();

What does upstream mean in nginx?

upstream defines a cluster that you can proxy requests to. It's commonly used for defining either a web server cluster for load balancing, or an app server cluster for routing / load balancing.

Change background image opacity

Nowadays, it is possible to do it simply with CSS property "background-blend-mode".

<div id="content">Only one div needed</div>

div#content {
    background-image: url(my_image.png);
    background-color: rgba(255,255,255,0.6);
    background-blend-mode: lighten;
    /* You may add things like width, height, background-size... */

It will blend the background-color (which is white, 0.6 opacity) into the background image. Learn more here (W3S).

Check the current number of connections to MongoDb

Connect to MongoDB using mongo-shell and run following command.



mongo> db.serverStatus().connections
{ "current" : 3, "available" : 816, "totalCreated" : NumberLong(1270) }

Xml serialization - Hide null values

In my case the nullable variables/elements were all String type. So, I simply performed a check and assigned them string.Empty in case of NULL. This way I got rid of the unnecessary nil and xmlns attributes (p3:nil="true" xmlns:p3="

// Example:

myNullableStringElement = varCarryingValue ?? string.Empty

// OR

myNullableStringElement = myNullableStringElement ?? string.Empty

How to print GETDATE() in SQL Server with milliseconds in time?

If your SQL Server version supports the function FORMAT you could do it like this:

select format(getdate(), 'yyyy-MM-dd HH:mm:ss.fff')

How to find most common elements of a list?

If you are using an earlier version of Python or you have a very good reason to roll your own word counter (I'd like to hear it!), you could try the following approach using a dict.

Python 2.6.1 (r261:67515, Feb 11 2010, 00:51:29) 
[GCC 4.2.1 (Apple Inc. build 5646)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> word_list = ['Jellicle', 'Cats', 'are', 'black', 'and', 'white,', 'Jellicle', 'Cats', 'are', 'rather', 'small;', 'Jellicle', 'Cats', 'are', 'merry', 'and', 'bright,', 'And', 'pleasant', 'to', 'hear', 'when', 'they', 'caterwaul.', 'Jellicle', 'Cats', 'have', 'cheerful', 'faces,', 'Jellicle', 'Cats', 'have', 'bright', 'black', 'eyes;', 'They', 'like', 'to', 'practise', 'their', 'airs', 'and', 'graces', 'And', 'wait', 'for', 'the', 'Jellicle', 'Moon', 'to', 'rise.', '']
>>> word_counter = {}
>>> for word in word_list:
...     if word in word_counter:
...         word_counter[word] += 1
...     else:
...         word_counter[word] = 1
>>> popular_words = sorted(word_counter, key = word_counter.get, reverse = True)
>>> top_3 = popular_words[:3]
>>> top_3
['Jellicle', 'Cats', 'and']

Top Tip: The interactive Python interpretor is your friend whenever you want to play with an algorithm like this. Just type it in and watch it go, inspecting elements along the way.

disable horizontal scroll on mobile web

Depending on box sizing width 100% might not always be the best option. I would suggest

 overflow-x: scroll;

This can be applied in the context of body, html as has been suggested or you could just wrap the content that is having an issue in a div with these settings applied.

Getting A File's Mime Type In Java

File file = new File(PropertiesReader.FILE_PATH);
MimetypesFileTypeMap fileTypeMap = new MimetypesFileTypeMap();
String mimeType = fileTypeMap.getContentType(file);
URLConnection uconnection = file.toURL().openConnection();
mimeType = uconnection.getContentType();

How do I analyze a .hprof file?

If you want to do a custom analysis of your heapdump then there's:

This library is fast but you will need to write your analysis code in Java.

From the docs:

  • Does not create any temporary files on disk to process heap dump
  • Can work directly GZ compressed heap dumps
  • HeapPath notation

Writing a new line to file in PHP (line feed)

You can also use file_put_contents():

file_put_contents('ids.txt', implode("\n", $gemList) . "\n", FILE_APPEND);

Download a file from HTTPS using download.file()

Offering the curl package as an alternative that I found to be reliable when extracting large files from an online database. In a recent project, I had to download 120 files from an online database and found it to half the transfer times and to be much more reliable than download.file.


ptm <- proc.time()
URL <- ""
x <- getURL(URL)
proc.time() - ptm

ptm1 <- proc.time()
curl_download(url =URL ,destfile="TEST.CSV",quiet=FALSE, mode="wb")
proc.time() - ptm1

ptm2 <- proc.time()
y = download.file(URL, destfile = "./data/data.csv", method="curl")
proc.time() - ptm2

In this case, rough timing on your URL showed no consistent difference in transfer times. In my application, using curl_download in a script to select and download 120 files from a website decreased my transfer times from 2000 seconds per file to 1000 seconds and increased the reliability from 50% to 2 failures in 120 files. The script is posted in my answer to a question I asked earlier, see .

Combine two columns of text in pandas dataframe

generalising to multiple columns, why not:

columns = ['whatever', 'columns', 'you', 'choose']
df['period'] = df[columns].astype(str).sum(axis=1)

How to load a tsv file into a Pandas DataFrame?

Note: As of 17.0 from_csv is discouraged: use pd.read_csv instead

The documentation lists a .from_csv function that appears to do what you want:

DataFrame.from_csv('c:/~/trainSetRel3.txt', sep='\t')

If you have a header, you can pass header=0.

DataFrame.from_csv('c:/~/trainSetRel3.txt', sep='\t', header=0)

CS0120: An object reference is required for the nonstatic field, method, or property 'foo'

Credit to @COOLGAMETUBE for tipping me off to what ended up working for me. His idea was good but I had a problem when Application.SetCompatibleTextRenderingDefault was called after the form was already created. So with a little change, this is working for me:

static class Program
    public static Form1 form1; // = new Form1(); // Place this var out of the constructor

/// <summary> /// The main entry point for the application. /// </summary> [STAThread] static void Main() { Application.EnableVisualStyles(); Application.SetCompatibleTextRenderingDefault(false); Application.Run(form1 = new Form1()); } }

String contains another two strings

If you have a list of words you can do a method like this:

public bool ContainWords(List<string> wordList, string text)
   foreach(string currentWord in wordList)
         return false;
   return true;

Using "label for" on radio buttons

Either structure is valid and accessible, but the for attribute should be equal to the id of the input element:

<input type="radio" ... id="r1" /><label for="r1">button text</label>


<label for="r1"><input type="radio" ... id="r1" />button text</label>

The for attribute is optional in the second version (label containing input), but IIRC there were some older browsers that didn't make the label text clickable unless you included it. The first version (label after input) is easier to style with CSS using the adjacent sibling selector +:

input[type="radio"]:checked+label {font-weight:bold;}

Magento: get a static block as html in a phtml file

I think this will work for you

$block = Mage::getModel('cms/block')->setStoreId(Mage::app()->getStore()->getId())->load('newest_product');
echo $block->getTitle();
echo $block->getContent();

It does work but now the variables in CMS block are not parsing anymore :(

Reading a file line by line in Go


  • reader.ReadString('\n')
    • If you don't mind that the line could be very long (i.e. use a lot of RAM). It keeps the \n at the end of the string returned.
  • reader.ReadLine()
    • If you care about limiting RAM consumption and don't mind the extra work of handling the case where the line is greater than the reader's buffer size.

I tested the various solutions suggested by writing a program to test the scenarios which are identified as problems in other answers:

  • A file with a 4MB line.
  • A file which doesn't end with a line break.

I found that:

  • The Scanner solution does not handle long lines.
  • The ReadLine solution is complex to implement.
  • The ReadString solution is the simplest and works for long lines.

Here is code which demonstrates each solution, it can be run via go run main.go, or at

package main

import (

func readFileWithReadString(fn string) (err error) {

    file, err := os.Open(fn)
    if err != nil {
        return err
    defer file.Close()

    // Start reading from the file with a reader.
    reader := bufio.NewReader(file)
    var line string
    for {
        line, err = reader.ReadString('\n')
        if err != nil && err != io.EOF {

        // Process the line here.
        fmt.Printf(" > Read %d characters\n", len(line))
        fmt.Printf(" > > %s\n", limitLength(line, 50))

        if err != nil {
    if err != io.EOF {
        fmt.Printf(" > Failed with error: %v\n", err)
        return err

func readFileWithScanner(fn string) (err error) {
    fmt.Println("readFileWithScanner (scanner fails with long lines)")

    // Don't use this, it doesn't work with long lines...

    file, err := os.Open(fn)
    if err != nil {
        return err
    defer file.Close()

    // Start reading from the file using a scanner.
    scanner := bufio.NewScanner(file)
    for scanner.Scan() {
        line := scanner.Text()

        // Process the line here.
        fmt.Printf(" > Read %d characters\n", len(line))
        fmt.Printf(" > > %s\n", limitLength(line, 50))
    if scanner.Err() != nil {
        fmt.Printf(" > Failed with error %v\n", scanner.Err())
        return scanner.Err()

func readFileWithReadLine(fn string) (err error) {

    file, err := os.Open(fn)
    if err != nil {
        return err
    defer file.Close()

    // Start reading from the file with a reader.
    reader := bufio.NewReader(file)
    for {
        var buffer bytes.Buffer

        var l []byte
        var isPrefix bool
        for {
            l, isPrefix, err = reader.ReadLine()
            // If we've reached the end of the line, stop reading.
            if !isPrefix {
            // If we're at the EOF, break.
            if err != nil {
                if err != io.EOF {
                    return err
        line := buffer.String()

        // Process the line here.
        fmt.Printf(" > Read %d characters\n", len(line))
        fmt.Printf(" > > %s\n", limitLength(line, 50))

        if err == io.EOF {
    if err != io.EOF {
        fmt.Printf(" > Failed with error: %v\n", err)
        return err

func main() {

func testLongLines() {
    fmt.Println("Long lines")


func testLinesThatDoNotFinishWithALinebreak() {
    fmt.Println("No linebreak")


func createFileThatDoesNotEndWithALineBreak(fn string) (err error) {
    file, err := os.Create(fn)
    if err != nil {
        return err
    defer file.Close()

    w := bufio.NewWriter(file)
    w.WriteString("Does not end with linebreak.")

func createFileWithLongLine(fn string) (err error) {
    file, err := os.Create(fn)
    if err != nil {
        return err
    defer file.Close()

    w := bufio.NewWriter(file)
    fs := 1024 * 1024 * 4 // 4MB
    // Create a 4MB long line consisting of the letter a.
    for i := 0; i < fs; i++ {
    // Terminate the line with a break.

    // Put in a second line, which doesn't have a linebreak.
    w.WriteString("Second line.")

func limitLength(s string, length int) string {
    if len(s) < length {
        return s
    return s[:length]

I tested on:

  • go version go1.15 darwin/amd64
  • go version go1.7 windows/amd64
  • go version go1.6.3 linux/amd64
  • go version go1.7.4 darwin/amd64

The test program outputs:

Long lines

 > Read 4194305 characters
 > > aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
 > Read 12 characters
 > > Second line.

readFileWithScanner (scanner fails with long lines)
 > Failed with error bufio.Scanner: token too long

 > Read 4194304 characters
 > > aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
 > Read 12 characters
 > > Second line.
 > Read 0 characters
 > > 

No linebreak

 > Read 28 characters
 > > Does not end with linebreak.

readFileWithScanner (scanner fails with long lines)
 > Read 28 characters
 > > Does not end with linebreak.

 > Read 28 characters
 > > Does not end with linebreak.
 > Read 0 characters
 > > 

In PHP, what is a closure and why does it use the "use" identifier?

closures are beautiful! they solve a lot of problems that come with anonymous functions, and make really elegant code possible (at least as long as we talk about php).

javascript programmers use closures all the time, sometimes even without knowing it, because bound variables aren't explicitly defined - that's what "use" is for in php.

there are better real-world examples than the above one. lets say you have to sort an multidimensional array by a sub-value, but the key changes.

    function generateComparisonFunctionForKey($key) {
        return function ($left, $right) use ($key) {
            if ($left[$key] == $right[$key])
                return 0;
                return ($left[$key] < $right[$key]) ? -1 : 1;

    $myArray = array(
        array('name' => 'Alex', 'age' => 70),
        array('name' => 'Enrico', 'age' => 25)

    $sortByName = generateComparisonFunctionForKey('name');
    $sortByAge  = generateComparisonFunctionForKey('age');

    usort($myArray, $sortByName);

    usort($myArray, $sortByAge);

warning: untested code (i don't have php5.3 installed atm), but it should look like something like that.

there's one downside: a lot of php developers may be a bit helpless if you confront them with closures.

to understand the nice-ty of closures more, i'll give you another example - this time in javascript. one of the problems is the scoping and the browser inherent asynchronity. especially, if it comes to window.setTimeout(); (or -interval). so, you pass a function to setTimeout, but you can't really give any parameters, because providing parameters executes the code!

function getFunctionTextInASecond(value) {
    return function () {
        document.getElementsByName('body')[0].innerHTML = value; // "value" is the bound variable!

var textToDisplay = prompt('text to show in a second', 'foo bar');

// this returns a function that sets the bodys innerHTML to the prompted value
var myFunction = getFunctionTextInASecond(textToDisplay);

window.setTimeout(myFunction, 1000);

myFunction returns a function with a kind-of predefined parameter!

to be honest, i like php a lot more since 5.3 and anonymous functions/closures. namespaces may be more important, but they're a lot less sexy.

Refresh Fragment at reload

protected void onResume() {

Do write viewpagerAdapter.notifyDataSetChanged(); in onResume() in MainActivity. Good Luck :)

What is the best way to access redux store outside a react component?

Found a solution. So I import the store in my api util and subscribe to it there. And in that listener function I set the axios' global defaults with my newly fetched token.

This is what my new api.js looks like:

// tooling modules
import axios from 'axios'

// store
import store from '../store'

function select(state) {
  return state.auth.tokens.authentication_token

function listener() {
  let token = select(store.getState())
  axios.defaults.headers.common['Authorization'] = token;

// configuration
const api = axios.create({
  baseURL: 'http://localhost:5001/api/v1',
  headers: {
    'Content-Type': 'application/json',

export default api

Maybe it can be further improved, cause currently it seems a bit inelegant. What I could do later is add a middleware to my store and set the token then and there.

How can I remove a child node in HTML using JavaScript?

If you want to clear the div and remove all child nodes, you could put:

var mydiv = document.getElementById('FirstDiv');
while(mydiv.firstChild) {

Load arrayList data into JTable

I created an arrayList from it and I somehow can't find a way to store this information into a JTable.

The DefaultTableModel doesn't support displaying custom Objects stored in an ArrayList. You need to create a custom TableModel.

You can check out the Bean Table Model. It is a reusable class that will use reflection to find all the data in your FootballClub class and display in a JTable.

Or, you can extend the Row Table Model found in the above link to make is easier to create your own custom TableModel by implementing a few methods. The source code give a complete example of how you can do this.

$.focus() not working

In my case, and in case someone else runs into this, I load a form for view, user clicks "Edit" and ajax gets & returns values and updates the form.

Just after this, I tried all of these and none worked except:

setTimeout(function() { $('input[name="q"]').focus() }, 3000);

which I had to change to (due to ajax):

setTimeout(function() { $('input[name="q"]').focus() }, **500**);

and I finally just used $("#q") even though it was an input:

setTimeout(function () { $("#q").focus() }, 500);

Importing variables from another file?

In Python you can access the contents of other files like as if they
are some kind of a library, compared to other languages like java or any oop base languages , This is really cool ;

This makes accessing the contents of the file or import it to to process it or to do anything with it ; And that is the Main reason why Python is highly preferred Language for Data Science and Machine Learning etc. ;

And this is the picture of project structure This

Where I am accessing variables from .env file where the API links and Secret keys reside .

General Structure:

from <File-Name> import *

Concatenating elements in an array to a string

I have just written the following:

public static String toDelimitedString(int[] ids, String delimiter)
    StringBuffer strb = new StringBuffer();
    for (int id : ids)
      strb.append(String.valueOf(id) + delimiter);
    return strb.substring(0, strb.length() - delimiter.length());

T-SQL split string based on delimiter

The examples above work fine when there is only one delimiter, but it doesn't scale well for multiple delimiters. Note that this will only work for SQL Server 2016 and above.

/*Some Sample Data*/
DECLARE @mytable TABLE ([id] VARCHAR(10), [name] VARCHAR(1000));
INSERT INTO @mytable
VALUES ('1','John/Smith'),('2','Jane/Doe'), ('3','Steve'), ('4','Bob/Johnson')

/*Split based on delimeter*/
SELECT, [1] 'FirstName', [2] 'LastName', [3] 'Col3', [4] 'Col4'
    FROM @mytable A
    ) A
PIVOT (MAX(A.[VALUE]) FOR A.RN IN ([1],[2],[3],[4],[5])) P

C# DataTable.Select() - How do I format the filter criteria to include null?

Try this

myDataTable.Select("[Name] is NULL OR [Name] <> 'n/a'" )

Edit: Relevant sources:

What is the difference between field, variable, attribute, and property in Java POJOs?

Actually these two terms are often used to represent same thing, but there are some exceptional situations. A field can store the state of an object. Also all fields are variables. So it is clear that there can be variables which are not fields. So looking into the 4 type of variables (class variable, instance variable, local variable and parameter variable) we can see that class variables and instance variables can affect the state of an object. In other words if a class or instance variable changes,the state of object changes. So we can say that class variables and instance variables are fields while local variables and parameter variables are not.

If you want to understand more deeply, you can head over to the source below:-

How do I use a regular expression to match any string, but at least 3 characters?

You could try with simple 3 dots. refer to the code in perl below

$a =~ m /.../ #where $a is your string

A valid provisioning profile for this executable was not found... (again)

I have spent about a week solving this problem. Most of the answers are sort of magic (no logical purposes for these algorithms) and they were not useful for me. I found this error in Xcode console:

ERROR ITMS-90174: "Missing Provisioning Profile - iOS Apps must contain a provisioning profile in a file named embedded.mobileprovision."

And found this answer solving this issue. The case is to switch Xcode Build system to the Legacy one.

I was deploying my Ionic app.

How to find the number of days between two dates

As @Forte L. mentioned you can do the following as well;

SELECT dtCreated
    , bActive
    , dtLastPaymentAttempt
    , dtLastUpdated
    , dtLastVisit

    , DATEDIFF(day, dtCreated, dtLastUpdated) Difference

FROM Customers
WHERE (bActive = 'true') 
    AND (dtLastUpdated > CONVERT(DATETIME, '2012-01-0100:00:00', 102))

How are booleans formatted in Strings in Python?

You may also use the Formatter class of string

print "{0} {1}".format(True, False);
print "{0:} {1:}".format(True, False);
print "{0:d} {1:d}".format(True, False);
print "{0:f} {1:f}".format(True, False);
print "{0:e} {1:e}".format(True, False);

These are the results

True False
True False
1 0
1.000000 0.000000
1.000000e+00 0.000000e+00

Some of the %-format type specifiers (%r, %i) are not available. For details see the Format Specification Mini-Language

How do I copy the contents of a String to the clipboard in C#?

WPF: System.Windows.Clipboard (PresentationCore.dll)

Winforms: System.Windows.Forms.Clipboard

Both have a static SetText method.

Check if string contains \n Java

If the string was constructed in the same program, I would recommend using this:

String newline = System.getProperty("line.separator");
boolean hasNewline = word.contains(newline);

But if you are specced to use \n, this driver illustrates what to do:

class NewLineTest {
    public static void main(String[] args) {
        String hasNewline = "this has a newline\n.";
        String noNewline = "this doesn't";




Resulted in


In reponse to your comment:

class NewLineTest {
    public static void main(String[] args) {
        String word = "test\n.";
        word = word.replace("\n","\n ");



Results in


Composer: how can I install another dependency without updating old ones?

Actually, the correct solution is:

composer require vendor/package

Taken from the CLI documentation for Composer:

The require command adds new packages to the composer.json file from the current directory.

php composer.phar require

After adding/changing the requirements, the modified requirements will be installed or updated.

If you do not want to choose requirements interactively, you can just pass them to the command.

php composer.phar require vendor/package:2.* vendor/package2:dev-master

While it is true that composer update installs new packages found in composer.json, it will also update the composer.lock file and any installed packages according to any fuzzy logic (> or * chars after the colons) found in composer.json! This can be avoided by using composer update vendor/package, but I wouldn't recommend making a habit of it, as you're one forgotten argument away from a potentially broken project…

Keep things sane and stick with composer require vendor/package for adding new dependencies!

Algorithm/Data Structure Design Interview Questions

This doesn't necessarily touch on OOP capabilities but in our last set of interviews we used a selection of buggy code from the Bug of the Month list. Watching the candidates find the bugs shows their analytical capabilities, shows the know how to interpret somebody elses code

Extract month and year from a zoo::yearmon object

Use the format() method for objects of class "yearmon". Here is your example date (properly created!)

date1 <- as.yearmon("Mar 2012", "%b %Y")

Then we can extract the date parts as required:

> format(date1, "%b") ## Month, char, abbreviated
[1] "Mar"
> format(date1, "%Y") ## Year with century
[1] "2012"
> format(date1, "%m") ## numeric month
[1] "03"

These are returned as characters. Where appropriate, wrap in as.numeric() if you want the year or numeric month as a numeric variable, e.g.

> as.numeric(format(date1, "%m"))
[1] 3
> as.numeric(format(date1, "%Y"))
[1] 2012

See ?yearmon and ?strftime for details - the latter explains the placeholder characters you can use.

How to stop the Timer in android?

We can schedule the timer to do the work.After the end of the time we set the message won't send.

This is the code.

Timer timer=new Timer();
timer.scheduleAtFixedRate(new TimerTask() {
    public void run() {
            //here you can write the code for send the message
    }, 10, 60000);

In here the method we are calling is,

public void scheduleAtFixedRate (TimerTask task, long delay, long period)

In here,

task : the task to schedule

delay: amount of time in milliseconds before first execution.

period: amount of time in milliseconds between subsequent executions.

For more information you can refer: Android Developer

You can stop the timer by calling,


What is 'Context' on Android?

Boss Assistant Analogy

Let's have a small analogy before diving deep in the technicality of Context

Every Boss has an assistant or someone( errand boy) who does less important and more time-consuming things for him. For example, if they need a file or coffee then an assistant will be on run. Boss will not know what is going on in the background but the file or the task will be delivered

So Here
Boss - Android Application
Assistant - Context
File or cup of coffee - Resource

What official Android Developer site says about Context

Context is your access point for application-related resources

Let's see some of such resources or tasks

  • Launching an activity.

  • Getting an absolute path to the application-specific cache directory on the filesystem.

  • Determining whether the given permission is allowed for a particular process and user ID running in the system.

  • Checking whether you have been granted a particular permission.

And so on.
So if an Android application wants to start an activity, it goes straight to Context (Access Point), and the Context class gives him back the resources(Intent in this case).

Like any other class Context class has fields and methods.
You can explore more about Context in official documentation, it covers pretty much everything, available methods, fields, and even how to use fields with methods.

Java: Literal percent sign in printf statement

Escaped percent sign is double percent (%%):

System.out.printf("2 out of 10 is %d%%", 20);

Where is Java's Array indexOf?

Array has no indexOf() method.

Maybe this Apache Commons Lang ArrayUtils method is what you are looking for

import org.apache.commons.lang3.ArrayUtils;

String[] colours = { "Red", "Orange", "Yellow", "Green" };

int indexOfYellow = ArrayUtils.indexOf(colours, "Yellow");

How to uninstall mini conda? python

If you are using windows, just search for miniconda and you'll find the folder. Go into the folder and you'll find a miniconda uninstall exe file. Run it.

How to set user environment variables in Windows Server 2008 R2 as a normal user?

Step by step instructions:

  • Go to Control Panel \System and Security\System
  • Click on Change Settings
  • Go to “Advance” tab
  • Click on Environment Variables

Is it possible to pass a flag to Gulp to have it run tasks in different ways?

If you've some strict (ordered!) arguments, then you can get them simply by checking process.argv.

var args = process.argv.slice(2);

if (args[0] === "--env" && args[1] === "production");

Execute it: gulp --env production

...however, I think that this is tooo strict and not bulletproof! So, I fiddled a bit around... and ended up with this utility function:

function getArg(key) {
  var index = process.argv.indexOf(key);
  var next = process.argv[index + 1];
  return (index < 0) ? null : (!next || next[0] === "-") ? true : next;

It eats an argument-name and will search for this in process.argv. If nothing was found it spits out null. Otherwise if their is no next argument or the next argument is a command and not a value (we differ with a dash) true gets returned. (That's because the key exist, but there's just no value). If all the cases before will fail, the next argument-value is what we get.

> gulp watch --foo --bar 1337 -boom "Foo isn't equal to bar."

getArg("--foo") // => true
getArg("--bar") // => "1337"
getArg("-boom") // => "Foo isn't equal to bar."
getArg("--404") // => null

Ok, enough for now... Here's a simple example using gulp:

var gulp = require("gulp");
var sass = require("gulp-sass");
var rename = require("gulp-rename");

var env = getArg("--env");

gulp.task("styles", function () {
  return gulp.src("./index.scss")
    style: env === "production" ? "compressed" : "nested"
    extname: env === "production" ? ".min.css" : ".css"

Run it gulp --env production

How to install lxml on Ubuntu

I installed lxml with pip in Vagrant, using Ubuntu 14.04 and had the same problem. Even though all requirements where installed, i got the same error again and again. Turned out, my VM had to little memory by default. With 1024 MB everything works fine.

Add this to your VagrantFile and lxml should properly compile / install:

config.vm.provider "virtualbox" do |vb|
  vb.memory = 1024

Thanks to sixhobbit for the hint (see: can't installing lxml on Ubuntu 12.04).

HTML5 <video> element on Android

I tried using the .mp4 format to play a video on Android devices but that did not go well. So after some trial and error, I converted the video into the .webm format and following code with no extra javascript or JQuery:

<video id="video" class="video" muted loop autoplay>
    <source src="../media/some_video.webm" type="video/webm">
    Sorry, your browser doesn't support embedded videos.

It worked on an older Android device (at least a few years old as of 2020).

How to clear all input fields in a specific div with jQuery?

Just had to delete all inputs within a div & using the colon in front of the input when targeting gets most everything.


AngularJS Directive Restrict A vs E


  1. Using your own html element like <my-directive></my-directive> wont work on IE8 without workaround (
  2. Using your own html elements will make html validation fail.
  3. Directives with equal one parameter can done like this:

<div data-my-directive="ValueOfTheFirstParameter"></div>

Instead of this:

<my-directive my-param="ValueOfTheFirstParameter"></my-directive>

We dont use custom html elements, because if this 2 facts.

Every directive by third party framework can be written in two ways:



<div data-my-directive></div>

does the same.

Vue JS mounted()

Abstract your initialization into a method, and call the method from mounted and wherever else you want.

new Vue({
      //call API
      //Setup game

Then possibly have a button in your template to start over.

<button v-if="playerWon" @click="init">Play Again</button>

In this button, playerWon represents a boolean value in your data that you would set when the player wins the game so the button appears. You would set it back to false in init.

SQL - ORDER BY 'datetime' DESC


SELECT post_datetime 
FROM post 
WHERE type = 'published' 
ORDER BY post_datetime DESC 

Write HTML string in JSON

You should escape the characters like double quotes in the html string by adding "\"

eg: <h2 class=\"fg-white\">

React : difference between <Route exact path="/" /> and <Route path="/" />

In this example, nothing really. The exact param comes into play when you have multiple paths that have similar names:

For example, imagine we had a Users component that displayed a list of users. We also have a CreateUser component that is used to create users. The url for CreateUsers should be nested under Users. So our setup could look something like this:

  <Route path="/users" component={Users} />
  <Route path="/users/create" component={CreateUser} />

Now the problem here, when we go to the router will go through all of our defined routes and return the FIRST match it finds. So in this case, it would find the Users route first and then return it. All good.

But, if we went to, it would again go through all of our defined routes and return the FIRST match it finds. React router does partial matching, so /users partially matches /users/create, so it would incorrectly return the Users route again!

The exact param disables the partial matching for a route and makes sure that it only returns the route if the path is an EXACT match to the current url.

So in this case, we should add exact to our Users route so that it will only match on /users:

  <Route exact path="/users" component={Users} />
  <Route path="/users/create" component={CreateUser} />

The docs explain exact in detail and give other examples.

REST API 404: Bad URI, or Missing Resource?

Use 404 if the resource does not exist. Don't return 200 with an empty body.

This is akin to undefined vs empty string (e.g. "") in programming. While very similar, there is definitely a difference.

404 means that nothing exists at that URI (like an undefined variable in programming). Returning 200 with an empty body means that something does exist there and that something is just empty right now (like an empty string in programming).

404 doesn't mean it was a "bad URI". There are special HTTP codes that are intended for URI errors (e.g. 414 Request-URI Too Long).

How can my iphone app detect its own version number?

This is what I did in my application

NSString *appVersion = [[[NSBundle mainBundle] infoDictionary] objectForKey:@"CFBundleVersion"];

Hopefully this simple answer will help somebody...

How do I split a string so I can access item x?

Yet another get n'th part of string by delimeter function:

create function GetStringPartByDelimeter (
    @value as nvarchar(max),
    @delimeter as nvarchar(max),
    @position as int
) returns NVARCHAR(MAX) 
    declare @startPos as int
    declare @endPos as int
    set @endPos = -1
    while (@position > 0 and @endPos != 0) begin
        set @startPos = @endPos + 1
        set @endPos = charindex(@delimeter, @value, @startPos)

        if(@position = 1) begin
            if(@endPos = 0)
                set @endPos = len(@value) + 1

            return substring(@value, @startPos, @endPos - @startPos)

        set @position = @position - 1

    return null

and the usage:

select dbo.GetStringPartByDelimeter ('a;b;c;d;e', ';', 3)

which returns:


Unix epoch time to Java Date object

How about just:

Date expiry = new Date(Long.parseLong(date));

EDIT: as per rde6173's answer and taking a closer look at the input specified in the question , "1081157732" appears to be a seconds-based epoch value so you'd want to multiply the long from parseLong() by 1000 to convert to milliseconds, which is what Java's Date constructor uses, so:

Date expiry = new Date(Long.parseLong(date) * 1000);

How can I print using JQuery

Try like


or if you want to print selected area try like


What's the difference between an Angular component and module

Component is the template(view) + a class (Typescript code) containing some logic for the view + metadata(to tell angular about from where to get data it needs to display the template).

Modules basically group the related components, services together so that you can have chunks of functionality which can then run independently. For example, an app can have modules for features, for grouping components for a particular feature of your app, such as a dashboard, which you can simply grab and use inside another application.

What is Join() in jQuery?

The practical use of this construct? It is a javascript replaceAll() on strings.

var s = 'stackoverflow_is_cool';  
s = s.split('_').join(' ');  

will output:

stackoverflow is cool

increment date by one month

You can use DateTime::modify like this :

$date = new DateTime('2010-12-11');
$date->modify('+1 month');

See documentations :

UPDATE january 2021 : correct mistakes raised by comments

This solution has some problems for months with 31 days like May etc.

Exemple : this jumps from 31st May to 1st July which is incorrect.

To correct that, you can create this custom function

function addMonths($date,$months){
    $init=clone $date;
    $modifier=$months.' months';
    $back_modifier =-$months.' months';
    $back_to_init= clone $date;
        $date->modify('-1 day')    ;
        $back_to_init= clone $date;

Then you can use it like that :

$date = new DateTime('2010-05-31');
addMonths($date, 1);
//DateTime Object ( [date] => 2010-06-30 00:00:00.000000 [timezone_type] => 3 [timezone] => Europe/Berlin ) 

This solution was found in posted by jenspj :

How do I get the computer name in .NET

Well there is one more way: Windows Management Instrumentation

using System.Management;

            ManagementObjectSearcher searcher =
                new ManagementObjectSearcher("root\\CIMV2",
                "SELECT Name FROM Win32_ComputerSystem");

            foreach (ManagementObject queryObj in searcher.Get())
                Console.WriteLine("Win32_ComputerSystem instance");
                Console.WriteLine("Name: {0}", queryObj["Name"]);
        catch (ManagementException e)
            // exception handling



WMI Code creator


Convert a date format in epoch

  String dateTime="15-3-2019 09:50 AM" //time should be two digit like 08,09,10 
   DateTimeFormatter dtf  = DateTimeFormatter.ofPattern("dd-MM-yyyy hh:mm a");
        LocalDateTime zdt  = LocalDateTime.parse(dateTime,dtf);
        LocalDateTime now =;
        ZoneId zone = ZoneId.of("Asia/Kolkata");
        ZoneOffset zoneOffSet = zone.getRules().getOffset(now);
        long a= zdt.toInstant(zoneOffSet).toEpochMilli();

you can get zone id form this a link!

How does strcmp() work?

This, from the masters themselves (K&R, 2nd ed., pg. 106):

// strcmp: return < 0 if s < t, 0 if s == t, > 0 if s > t
int strcmp(char *s, char *t) 
    int i;

    for (i = 0; s[i] == t[i]; i++)
        if (s[i] == '\0')
            return 0;
    return s[i] - t[i];

Add Items to Columns in a WPF ListView

Solution With Less XAML and More C#

If you define the ListView in XAML:

<ListView x:Name="listView"/>

Then you can add columns and populate it in C#:

public Window()
    // Initialize

    // Add columns
    var gridView = new GridView();
    this.listView.View = gridView;
    gridView.Columns.Add(new GridViewColumn { 
        Header = "Id", DisplayMemberBinding = new Binding("Id") });
    gridView.Columns.Add(new GridViewColumn { 
        Header = "Name", DisplayMemberBinding = new Binding("Name") });

    // Populate list
    this.listView.Items.Add(new MyItem { Id = 1, Name = "David" });

See definition of MyItem below.

Solution With More XAML and less C#

However, it's easier to define the columns in XAML (inside the ListView definition):

<ListView x:Name="listView">
            <GridViewColumn Header="Id" DisplayMemberBinding="{Binding Id}"/>
            <GridViewColumn Header="Name" DisplayMemberBinding="{Binding Name}"/>

And then just populate the list in C#:

public Window()
    // Initialize

    // Populate list
    this.listView.Items.Add(new MyItem { Id = 1, Name = "David" });

See definition of MyItem below.

MyItem Definition

MyItem is defined like this:

public class MyItem
    public int Id { get; set; }

    public string Name { get; set; }

How can I perform a str_replace in JavaScript, replacing text in JavaScript?

Method to replace substring in a sentence using React:

 const replace_in_javascript = (oldSubStr, newSubStr, sentence) => {
    let newStr = "";
    let i = 0;
    sentence.split(" ").forEach(obj => {
      if (obj.toUpperCase() === oldSubStr.toUpperCase()) {
        newStr = i === 0 ? newSubStr : newStr + " " + newSubStr;
        i = i + 1;
      } else {
        newStr = i === 0 ? obj : newStr + " " + obj;
        i = i + 1;
    return newStr;


Hide Text with CSS, Best Practice?

If you're willing to accomodate this in your markup (as you are in your question with the holding the text), I'd go with whatever jQuery UI went with in their CSS helpers:

.ui-helper-hidden-accessible { 
    position: absolute !important; 
    clip: rect(1px 1px 1px 1px); 
    clip: rect(1px,1px,1px,1px); 

The image replacement techniques are good if you absolutely refuse to add extra markup for the text to be hidden in the container for the image.

When to use static methods

Static methods are the methods in Java that can be called without creating an object of class. It is belong to the class.

We use static method when we no need to be invoked method using instance.

How to catch exception correctly from http.request()?

in the latest version of angular4 use

import { Observable } from 'rxjs/Rx'

it will import all the required things.

How to load a model from an HDF5 file in Keras?

If you stored the complete model, not only the weights, in the HDF5 file, then it is as simple as

from keras.models import load_model
model = load_model('model.h5')

How can I use NSError in my iPhone App?

Another design pattern that I have seen involves using blocks, which is especially useful when a method is being run asynchronously.

Say we have the following error codes defined:

typedef NS_ENUM(NSInteger, MyErrorCodes) {
    MyErrorCodesEmptyString = 500,

You would define your method that can raise an error like so:

- (void)getContentsOfURL:(NSString *)path success:(void(^)(NSString *html))success failure:(void(^)(NSError *error))failure {
    if (path.length == 0) {
        if (failure) {
            failure([NSError errorWithDomain:@"com.example" code:MyErrorCodesEmptyString userInfo:nil]);

    NSString *htmlContents = @"";

    // Exercise for the reader: get the contents at that URL or raise another error.

    if (success) {

And then when you call it, you don't need to worry about declaring the NSError object (code completion will do it for you), or checking the returning value. You can just supply two blocks: one that will get called when there is an exception, and one that gets called when it succeeds:

[self getContentsOfURL:@"" success:^(NSString *html) {
    NSLog(@"Contents: %@", html);
} failure:^(NSError *error) {
    NSLog(@"Failed to get contents: %@", error);
    if (error.code == MyErrorCodesEmptyString) { // make sure to check the domain too
        NSLog(@"You must provide a non-empty string");

How to implement a custom AlertDialog View

This worked for me:

dialog.setView(dialog.getLayoutInflater().inflate(R.layout.custom_dialog_layout, null));

How can I solve "Either the parameter @objname is ambiguous or the claimed @objtype (COLUMN) is wrong."?

Are you running the query in the correct database? i.e.,

Use MyDatabase;
EXEC sp_rename 'ENG_TEst.[ENG_Test_A/C_TYPE]', 'ENG_Test_AC_TYPE', 'COLUMN';

Using NULL in C++?

From crtdbg.h (and many other headers):

#ifndef NULL
#ifdef __cplusplus
#define NULL    0
#define NULL    ((void *)0)

Therefore NULL is 0, at least on the Windows platform. So no, not that I know of.

Filtering DataGridView without changing datasource

I have a clearer proposal on automatic search in a DataGridView

this is an example

private void searchTb_TextChanged(object sender, EventArgs e)
            (lecteurdgview.DataSource as DataTable).DefaultView.RowFilter = String.IsNullOrEmpty(searchTb.Text) ?
                "lename IS NOT NULL" :
                String.Format("lename LIKE '{0}' OR lecni LIKE '{1}' OR ledatenais LIKE '{2}' OR lelieu LIKE '{3}'", searchTb.Text, searchTb.Text, searchTb.Text, searchTb.Text);
        catch (Exception ex) {

How to increment a datetime by one day?

This was a straightforward solution for me:

from datetime import timedelta, datetime

today ="%Y-%m-%d")
tomorrow = + timedelta(1)

Remove Item in Dictionary based on Value

Are you trying to remove a single value or all matching values?

If you are trying to remove a single value, how do you define the value you wish to remove?

The reason you don't get a key back when querying on values is because the dictionary could contain multiple keys paired with the specified value.

If you wish to remove all matching instances of the same value, you can do this:

foreach(var item in dic.Where(kvp => kvp.Value == value).ToList())

And if you wish to remove the first matching instance, you can query to find the first item and just remove that:

var item = dic.First(kvp => kvp.Value == value);


Note: The ToList() call is necessary to copy the values to a new collection. If the call is not made, the loop will be modifying the collection it is iterating over, causing an exception to be thrown on the next attempt to iterate after the first value is removed.

Connect Java to a MySQL database

Short and Sweet code.

try {       
    System.out.println("Driver Loaded");
    conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/testDB","root","");
    //Database Name - testDB, Username - "root", Password - ""
} catch(Exception e) {

For SQL server 2012

try {
    String url = "jdbc:sqlserver://KHILAN:1433;databaseName=testDB;user=Khilan;password=Tuxedo123"; 
    //KHILAN is Host    and 1433 is port number     
    System.out.println("Driver Loaded");
    conn = DriverManager.getConnection(url);
} catch(Exception e) {

Boolean operators && and ||

The answer about "short-circuiting" is potentially misleading, but has some truth (see below). In the R/S language, && and || only evaluate the first element in the first argument. All other elements in a vector or list are ignored regardless of the first ones value. Those operators are designed to work with the if (cond) {} else{} construction and to direct program control rather than construct new vectors.. The & and the | operators are designed to work on vectors, so they will be applied "in parallel", so to speak, along the length of the longest argument. Both vectors need to be evaluated before the comparisons are made. If the vectors are not the same length, then recycling of the shorter argument is performed.

When the arguments to && or || are evaluated, there is "short-circuiting" in that if any of the values in succession from left to right are determinative, then evaluations cease and the final value is returned.

> if( print(1) ) {print(2)} else {print(3)}
[1] 1
[1] 2
> if(FALSE && print(1) ) {print(2)} else {print(3)} # `print(1)` not evaluated
[1] 3
> if(TRUE && print(1) ) {print(2)} else {print(3)}
[1] 1
[1] 2
> if(TRUE && !print(1) ) {print(2)} else {print(3)}
[1] 1
[1] 3
> if(FALSE && !print(1) ) {print(2)} else {print(3)}
[1] 3

The advantage of short-circuiting will only appear when the arguments take a long time to evaluate. That will typically occur when the arguments are functions that either process larger objects or have mathematical operations that are more complex.

Rendering HTML in a WebView with custom CSS

You can Use Online Css link To set Style over existing content.

For That you have to load data in webview and enable JavaScript Support.

See Below Code:

   WebSettings webSettings=web_desc.getSettings();
    StringBuilder sb = new StringBuilder();
    sb.append("<HTML><HEAD><LINK href=\"\" type=\"text/css\" rel=\"stylesheet\"/></HEAD><body>");
    currentWebView.loadDataWithBaseURL("file:///android_asset/", sb.toString(), "text/html", "utf-8", null);

Here Use StringBuilder to append String for Style.

sb.append("<HTML><HEAD><LINK href=\"\" type=\"text/css\" rel=\"stylesheet\"/></HEAD><body>");

taking input of a string word by word

getline is storing the entire line at once, which is not what you want. A simple fix is to have three variables and use cin to get them all. C++ will parse automatically at the spaces.

#include <iostream>
using namespace std;

int main() {
    string a, b, c;
    cin >> a >> b >> c;
    //now you have your three words
    return 0;

I don't know what particular "operation" you're talking about, so I can't help you there, but if it's changing characters, read up on string and indices. The C++ documentation is great. As for using namespace std; versus std:: and other libraries, there's already been a lot said. Try these questions on StackOverflow to start.

What does %~dp0 mean, and how does it work?

The variable %0 in a batch script is set to the name of the executing batch file.

The ~dp special syntax between the % and the 0 basically says to expand the variable %0 to show the drive letter and path, which gives you the current directory containing the batch file!

Help = Link

Document Root PHP

The Easiest way to do it is to have good site structure and write it as a constant.


How to position the Button exactly in CSS

I'd use absolute positioning:

#play_button {
transition: .5s ease;
    left: 202px;
    top: 198px;


Angular2 multiple router-outlet in the same template

Yes you can as said by @tomer above. i want to add some point to @tomer answer.

  • firstly you need to provide name to the router-outlet where you want to load the second routing view in your view. (aux routing angular2.)
  • In angular2 routing few important points are here.

    • path or aux (requires exactly one of these to give the path you have to show as the url).
    • component, loader, redirectTo (requires exactly one of these, which component you want to load on routing)
    • name or as (optional) (requires exactly one of these, the name which specify at the time of routerLink)
    • data (optional, whatever you want to send with the routing that you have to get using routerParams at the receiver end.)

for more info read out here and here.

import {RouteConfig, AuxRoute} from 'angular2/router';
  new AuxRoute({path: '/home', component: HomeCmp})
class MyApp {}

MySQL connection not working: 2002 No such file or directory

Not that it helps you much, but in the recent versions (and even less recent) of MySQL, error code 2002 means “Can't connect to local MySQL server through socket [name-of-socket]”, so that might tell you a bit more.

Finding median of list in Python

import numpy as np
def get_median(xs):
        mid = len(xs) // 2  # Take the mid of the list
        if len(xs) % 2 == 1: # check if the len of list is odd
            return sorted(xs)[mid] #if true then mid will be median after sorting
            #return 0.5 * sum(sorted(xs)[mid - 1:mid + 1])
            return 0.5 * np.sum(sorted(xs)[mid - 1:mid + 1]) #if false take the avg of mid
print(get_median([7, 7, 3, 1, 4, 5]))
print(get_median([1,2,3, 4,5]))

Proper way to handle multiple forms on one page in Django

I needed multiple forms that are independently validated on the same page. The key concepts I was missing were 1) using the form prefix for the submit button name and 2) an unbounded form does not trigger validation. If it helps anyone else, here is my simplified example of two forms AForm and BForm using TemplateView based on the answers by @adam-nelson and @daniel-sokolowski and comment by @zeraien (

def _get_form(request, formcls, prefix):
    data = request.POST if prefix in request.POST else None
    return formcls(data, prefix=prefix)

class MyView(TemplateView):
    template_name = 'mytemplate.html'

    def get(self, request, *args, **kwargs):
        return self.render_to_response({'aform': AForm(prefix='aform_pre'), 'bform': BForm(prefix='bform_pre')})

    def post(self, request, *args, **kwargs):
        aform = _get_form(request, AForm, 'aform_pre')
        bform = _get_form(request, BForm, 'bform_pre')
        if aform.is_bound and aform.is_valid():
            # Process aform and render response
        elif bform.is_bound and bform.is_valid():
            # Process bform and render response
        return self.render_to_response({'aform': aform, 'bform': bform})

# mytemplate.html
<form action="" method="post">
    {% csrf_token %}
    {{ aform.as_p }}
    <input type="submit" name="{{aform.prefix}}" value="Submit" />
    {{ bform.as_p }}
    <input type="submit" name="{{bform.prefix}}" value="Submit" />

is of a type that is invalid for use as a key column in an index

The only solution is to use less data in your Unique Index. Your key can be NVARCHAR(450) at most.

"SQL Server retains the 900-byte limit for the maximum total size of all index key columns."

Read more at MSDN

How do I run Visual Studio as an administrator by default?

Windows 10

  1. Right click "Visual Studio" and select "Open file location Right click "Visual Studio" and select "Open file location"
  2. Right click "Visual Studio" and select "Properties" Right click "Visual Studio" and select "Properties"
  3. Click "Advanced" and check "Run as administrator" Click "Advanced" and check "Run as administrator"

Undo git stash pop that results in merge conflict

git checkout -f

must work, if your previous state is clean.

How to prevent buttons from submitting forms

The function removeItem actually contains an error, which makes the form button do it's default behaviour (submitting the form). The javascript error console will usually give a pointer in this case.

Check out the function removeItem in the javascript part:

The line:


doesn't work. Try this instead:


How to run stored procedures in Entity Framework Core?

"(SqlConnection)context" -- This type-casting no longer works. You can do: "SqlConnection context;

".AsSqlServer()" -- Does not Exist.

"command.ExecuteNonQuery();" -- Does not return results. reader=command.ExecuteReader() does work.

With dt.load(reader)... then you have to switch the framework out of 5.0 and back to 4.51, as 5.0 does not support datatables/datasets, yet. Note: This is VS2015 RC.

how do I give a div a responsive height

I know this is a little late to the party but you could use viewport units


Viewport units: vw, vh, vmin, vmax - CR Length units representing 1% of the viewport size for viewport width (vw), height (vh), the smaller of the two (vmin), or the larger of the two (vmax).


div {_x000D_
/* 25% of viewport */_x000D_
  height: 25vh;_x000D_
  width: 15rem;_x000D_
  background-color: #222;_x000D_
  color: #eee;_x000D_
  font-family: monospace;_x000D_
  padding: 2rem;_x000D_
<div>responsive height</div>

How can I create download link in HTML?

i know i am late but this is what i got after 1 hour of search

      $file = 'file.pdf';

    if (! file) {
        die('file not found'); //Or do something 
    } else {
        // Set headers
        header("Cache-Control: public");
        header("Content-Description: File Transfer");
        header("Content-Disposition: attachment; filename=$file");
        header("Content-Type: application/zip");
        header("Content-Transfer-Encoding: binary");
        // Read the file from disk
        readfile($file); }


and for downloadable link i did this

<a href="index.php?file=file.pdf">Download PDF</a>

Find duplicate lines in a file and count how many time each line was duplicated?

To find duplicate counts use below command as requested by you :

sort filename | uniq -c | awk '{print $2, $1}'

git: diff between file in local repo and origin

Full answer to the original question that was talking about a possible different path on local and remote is below

  1. git fetch origin
  2. git diff master -- [local-path] origin/master -- [remote-path]

Assuming the local path is docs/file1.txt and remote path is docs2/file1.txt, use git diff master -- docs/file1.txt origin/master -- docs2/file1.txt

This is adapted from GitHub help page here and Code-Apprentice answer above

Redirecting to another page in ASP.NET MVC using JavaScript/jQuery

This could be done by using a hidden variable in the view and then using that variable to post from the JavaScript code.

Here is my code in the view

@Html.Hidden("RedirectTo", Url.Action("ActionName", "ControllerName"));

Now you can use this in the JavaScript file as:

 var url = $("#RedirectTo").val();
 location.href = url;

It worked like a charm fro me. I hope it helps you too.

Python circular importing?

I was using the following:

from module import Foo

foo_instance = Foo()

but to get rid of circular reference I did the following and it worked:


foo_instance = foo.Foo()

Html.EditorFor Set Default Value

This worked for me

In Controlle

 ViewBag.AAA = default_Value ;

In View

@Html.EditorFor(model => model.AAA, new { htmlAttributes = new { @Value = ViewBag.AAA } }

Best place to insert the Google Analytics code

Yes, it is recommended to put the GA code in the footer anyway, as the page shouldnt count as a page visit until its read all the markup.

In ASP.NET MVC: All possible ways to call Controller Action Method from a Razor View

Method 1 : Using jQuery Ajax Get call (partial page update).

Suitable for when you need to retrieve jSon data from database.

Controller's Action Method

public ActionResult Foo(string id)
    var person = Something.GetPersonByID(id);
    return Json(person, JsonRequestBehavior.AllowGet);

Jquery GET

function getPerson(id) {
        url: '@Url.Action("Foo", "SomeController")',
        type: 'GET',
        dataType: 'json',
        // we set cache: false because GET requests are often cached by browsers
        // IE is particularly aggressive in that respect
        cache: false,
        data: { id: id },
        success: function(person) {

Person class

public class Person
    public string FirstName { get; set; }
    public string LastName { get; set; }

Method 2 : Using jQuery Ajax Post call (partial page update).

Suitable for when you need to do partial page post data into database.

Post method is also same like above just replace [HttpPost] on Action method and type as post for jquery method.

For more information check Posting JSON Data to MVC Controllers Here

Method 3 : As a Form post scenario (full page update).

Suitable for when you need to save or update data into database.


@using (Html.BeginForm("SaveData","ControllerName", FormMethod.Post))
    @Html.TextBoxFor(model => m.Text)
    <input type="submit" value="Save" />

Action Method

public ActionResult SaveData(FormCollection form)
        // Get movie to update
        return View();

Method 4 : As a Form Get scenario (full page update).

Suitable for when you need to Get data from database

Get method also same like above just replace [HttpGet] on Action method and FormMethod.Get for View's form method.

I hope this will help to you.

How can I copy a Python string?

You can copy a string in python via string formatting :

>>> a = 'foo'  
>>> b = '%s' % a  
>>> id(a), id(b)  
(140595444686784, 140595444726400)  

Use chrome as browser in C#?

I use Awesomium, I think it is better than GeckoFX/WebKit

'Property does not exist on type 'never'

Because you are assigning instance to null. The compiler infers that it can never be anything other than null. So it assumes that the else block should never be executed so instance is typed as never in the else block.

Now if you don't declare it as the literal value null, and get it by any other means (ex: let instance: Foo | null = getFoo();), you will see that instance will be null inside the if block and Foo inside the else block.

Never type documentation:


The issue in the updated example is actually an open issue with the compiler. See:

transform object to array with lodash

var arr =

You can use function (of both lodash and underscore) with object as well, it will internally handle that case, iterate over each value and key with your iteratee, and finally return an array. Infact, you can use it without any iteratee (just if you just want a array of values. The good part is that, if you need any transformation in between, you can do it in one go.


var obj = {_x000D_
    key1: {id: 1, name: 'A'},_x000D_
    key2: {id: 2, name: 'B'},_x000D_
    key3: {id: 3, name: 'C'}_x000D_
var array1 =, v=>v);_x000D_
console.log('Array 1: ', array1);_x000D_
/*Actually you don't need the callback v=>v if you_x000D_
are not transforming anything in between, v=>v is default*/_x000D_
//SO simply you can use_x000D_
var array2 =;_x000D_
console.log('Array 2: ', array2);
<script src=""></script>

However, if you want to transform your object you can do so, even if you need to preserve the key, you can do that (, (v, k) => {...}) with additional argument in map and then use it how you want.

However there are other Vanilla JS solution to this (as every lodash solution there should pure JS version of it) like:

  • Object.keys and then map them to values
  • Object.values (in ES-2017)
  • Object.entries and then map each key/value pairs (in ES-2017)
  • loop and use each keys for feting values

And a lot more. But since this question is for lodash (and assuming someone already using it) then you don't need to think a lot about version, support of methods and error handling if those are not found.

There are other lodash solutions like _.values (more readable for specific perpose), or getting pairs and then map and so on. but in the case your code need flexibility that you can update it in future as you need to preserve keys or transforming values a bit, then the best solution is to use a single as addresed in this answer. That will bt not that difficult as per readability also.

Remove json element

I recommend splice method to remove an object from JSON objects array.

jQuery(json).each(function (index){
        if(json[index].FirstName == "Test1"){
            json.splice(index,1); // This will remove the object that first name equals to Test1
            return false; // This will stop the execution of jQuery each loop.

I use this because when I use delete method, I get null object after I do JSON.stringify(json)

How to add border radius on table row

I found that adding border-radius to tables, trs, and tds does not seem to work 100% in the latest versions of Chrome, FF, and IE. What I do instead is, I wrap the table with a div and put the border-radius on it.

<div class="tableWrapper">

.tableWrapper {
  border-radius: 4px;
  overflow: hidden;

If your table is not width: 100%, you can make your wrapper float: left, just remember to clear it.

Javascript: Extend a Function

Use extendFunction.js

init = extendFunction(init, function(args) {

But in your specific case, it's easier to extend the global onload function:

extendFunction('onload', function(args) {

I actually really like your question, it's making me think about different use cases.

For javascript events, you really want to add and remove handlers - but for extendFunction, how could you later remove functionality? I could easily add a .revert method to extended functions, so init = init.revert() would return the original function. Obviously this could lead to some pretty bad code, but perhaps it lets you get something done without touching a foreign part of the codebase.

OWIN Startup Class Missing

Are you really trying to add OWIN to your project or is this something unexpected?

  1. In case you want to add OWIN, adding a Startup class is the way to go.

  2. In case you don't need any reference to Owin:

    delete Owin.dll from your /bin folder.

    Owin.dll is the one trying to identify the Startup class.

How is AngularJS different from jQuery

AngularJS : AngularJS is for developing heavy web applications. AngularJS can use jQuery if it’s present in the web-app when the application is being bootstrapped. If it's not present in the script path, then AngularJS falls back to its own implementation of the subset of jQuery.

JQuery : jQuery is a small, fast, and feature-rich JavaScript library. It makes things like HTML document traversal and manipulation, event handling, animation, and Ajax much simpler. jQuery simplifies a lot of the complicated things from JavaScript, like AJAX calls and DOM manipulation.

Read more details here: angularjs-vs-jquery

Calling another method java GUI

I'm not sure what you're trying to do, but here's something to consider: c(); won't do anything. c is an instance of the class checkbox and not a method to be called. So consider this:

public class FirstWindow extends JFrame {      public FirstWindow() {         checkbox c = new checkbox();         c.yourMethod(yourParameters); // call the method you made in checkbox     } }  public class checkbox extends JFrame {      public checkbox(yourParameters) {          // this is the constructor method used to initialize instance variables     }      public void yourMethod() // doesn't have to be void     {         // put your code here     } } 

Request header field Access-Control-Allow-Headers is not allowed by itself in preflight response

This problem solved with

 "Origin, X-Requested-With, Content-Type, Accept, Authorization"

Particular in my project (express.js/nodejs)

app.use(function(req, res, next) {
  res.header("Access-Control-Allow-Origin", "*");
  res.header("Access-Control-Allow-Methods", "GET,HEAD,OPTIONS,POST,PUT");
  res.header("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept, Authorization");


Every time error: Access-Control-Allow-Headers is not allowed by itself in preflight response error you can see what wrong with chrome developer tool:
enter image description here

above error is missing Content-Type so add string Content-Type to Access-Control-Allow-Headers

CSS Positioning Elements Next to each other

If you want them to be displayed side by side, why is sideContent the child of mainContent? make them siblings then use:

float:left; display:inline; width: 49%;

on both of them.

#mainContent, #sideContent {float:left; display:inline; width: 49%;}

Node JS Promise.all and forEach

I had through the same situation. I solved using two Promise.All().

I think was really good solution, so I published it on npm:

I think your code will be something like this

var promiseForeach = require('promise-foreach')
var jsonItems = [];
    [function (jsonItems){
        return new Promise(function(resolve, reject){
            if(jsonItems.type === 'file'){
                jsonItems.getFile().then(function(file){ //or promise.all?
    function (result, current) {
        return {
            type: current.type,
            size: jsonItems.result[0]
    function (err, newList) {
        if (err) {
        console.log('new jsonItems : ', newList)

How to switch activity without animation in Android?

You can also just do this in all the activities that you dont want to transition from:

public void onPause() {
    overridePendingTransition(0, 0);

I like this approach because you do not have to mess with the style of your activity.

Installing PG gem on OS X - failure to build native extension

Solved! I found some lack of library for PostgreSQL on the system. Only two steps solved it:

brew install postgresql

Then run

gem install pg

if block inside echo statement?

In sake of readability it should be something like

  $countries = $myaddress->get_countries();
  foreach($countries as $value) {
    $selected ='';
    if($value=='United States') $selected ='selected="selected"'; 
    echo '<option value="'.$value.'"'.$selected.'>'.$value.'</option>';

desire to stuff EVERYTHING in a single line is a decease, man. Write distinctly.

But there is another way, a better one. There is no need to use echo at all. Learn to use templates. Prepare your data first, and display it only then ready.

Business logic part:

$countries = $myaddress->get_countries();
$selected_country = 1;    

Template part:

<? foreach($countries as $row): ?>
<option value="<?=$row['id']?>"<? if ($row['id']==$current_country):> "selected"><? endif ?>
<? endforeach ?>