Tutorial by Examples: en

Since PHP objects don't inherit from any base class (including stdClass), there is no support for type hinting a generic object type. For example, the below will not work. <?php function doSomething(object $obj) { return $obj; } class ClassOne {} class ClassTwo {} $classOne= new...

There are multiple threads in your code and you need to safely communicate between them. You can use a Queue from the queue library. from queue import Queue from threading import Thread # create a data producer def producer(output_queue): while True: data = data_computation() ...

In Objective-C, method swizzling is the process of changing the implementation of an existing selector. This is possible due to the way Selectors are mapped on a dispatch table, or a table of pointers to functions or methods. Pure Swift methods are not dynamically dispatched by the Objective-C run...

Putting a & (ampersand) in front of an argument will pass it as the method's block. Objects will be converted to a Proc using the to_proc method. class Greeter def to_proc Proc.new do |item| puts "Hello, #{item}" end end end greet = Greeter.new %w(world l...

In this approach, the single is accessed via the static method: Singleton.getInstance(); To enforce only one instance of the singleton, a private static variable retains the instance, while any additional attempts to instantiate an instance are enforced within the constructor. package { publ...

The background-attachment property sets whether a background image is fixed or scrolls with the rest of the page. body { background-image: url('img.jpg'); background-attachment: fixed; } ValueDescriptionscrollThe background scrolls along with the element. This is default.fixedThe backgro...

Math.random(); produces an evenly distributed random number between 0 (inclusive) and 1 (exclusive) Example output: 0.22282187035307288 0.3948539895936847 0.9987191134132445

function randomMinMax(min:Number, max:Number):Number { return (min + (Math.random() * Math.abs(max - min))); } This function is called by passing a range of minimum and maximum values. Example: randomMinMax(1, 10); Example outputs: 1.661770915146917 2.5521070677787066 9.4362709657...

int a = 1; int *a_pointer = &a; To dereference a_pointer and change the value of a, we use the following operation *a_pointer = 2; This can be verified using the following print statements. printf("%d\n", a); /* Prints 2 */ printf("%d\n", *a_pointer); /* Also prints...

Destructuring allows us to refer to one key in an object, but declare it as a variable with a different name. The syntax looks like the key-value syntax for a normal JavaScript object. let user = { name: 'John Smith', id: 10, email: '[email protected]', }; let {user: userName, id: us...

HTML 4.01/XHTML 1.0 Strict includes the following void elements: area - clickable, defined area in an image base - specifies a base URL from which all links base br - line break col - column in a table [deprecated] hr - horizontal rule (line) img - image input - field where users enter data...

To find all the files of a certain extension within the current path you can use the following find syntax. It works by making use of bash's built-in glob construct to match all the names having the .extension. find /directory/to/search -maxdepth 1 -type f -name "*.extension" To find ...

It is also possible to write a context manager using generator syntax thanks to the contextlib.contextmanager decorator: import contextlib @contextlib.contextmanager def context_manager(num): print('Enter') yield num + 1 print('Exit') with context_manager(2) as cm: # the ...

Intents can be used to broadcast messages to other components of your application (such as a running background service) or to the entire Android system. To send a broadcast within your application, use the LocalBroadcastManager class: Intent intent = new Intent("com.example.YOUR_ACTION"...

You can access SharedPreferences in several ways: Get the default SharedPreferences file: import android.preference.PreferenceManager; SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this); Get a specific SharedPreferences file: public static final String PREF_FILE_NAM...

SRXMPPDemo Download the example and all the classes here - https://github.com/SahebRoy92/SRXMPPDemo A demo on XMPP in Objective C, with various simple and complex features implemented in it. All the features of XMPP is done by "in band" xmpp functions. Few features this project contains...

Using the Array::new constructor, your can initialize an array with a given size and a new array in each of its slots. The inner arrays can also be given a size and and initial value. For instance, to create a 3x4 array of zeros: array = Array.new(3) { Array.new(4) { 0 } } The array generated a...

Define your class that will represent your custom error. public class ErrorDto { public int Code { get; set; } public string Message { get; set; } // other fields public override string ToString() { return JsonConvert.SerializeObject(this); } } Then put nex...

The idea is to use HttpContext.Response.OnStarting callback, as this is the last event that is fired before the headers are sent. Add the following to your middleware Invoke method. public async Task Invoke(HttpContext context) { context.Response.OnStarting((state) => { if ...

Enumerable is the most popular module in Ruby. Its purpose is to provide you with iterable methods like map, select, reduce, etc. Classes that use Enumerable include Array, Hash, Range. To use it, you have to include Enumerable and implement each. class NaturalNumbers include Enumerable de...