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POSIX character classes are predefined sequences for a certain set of characters. Character classDescription[:alpha:]Alphabetic characters[:alnum:]Alphabetic characters and digits[:digit:]Digits[:xdigit:]Hexadecimal digits[:blank:]Space and Tab[:cntrl:]Control characters[:graph:]Visible characters ...

Most basic Django debugging tool is pdb, a part of Python standard library. Init view script Let's examine a simple views.py script: from django.http import HttpResponse def index(request): foo = 1 bar = 0 bug = foo/bar return HttpResponse("%d goes here." % ...

private List<FooBar> _fooBars; public List<FooBar> FooBars { get { return _fooBars ?? (_fooBars = new List<FooBar>()); } } The first time the property .FooBars is accessed the _fooBars variable will evaluate as null, thus falling through to the assignment statement ass...

To get started with unit testing, which will be done in the tests file and will be testing the View Controller and Storyboard, we should introduce these two files to the test file. Defining the View Controller Swift var viewController : ViewController! Introducing the Storyboard and initializi...

To stop the Handler from execution remove the callback attached to it using the runnable running inside it: Runnable my_runnable = new Runnable() { @Override public void run() { // your code here } }; public Handler handler = new Handler(); // use 'new Handler(Looper.get...

In order to call a function through a function pointer, the function pointer's type must exactly match the function's type. Otherwise, the behaviour is undefined. Example: int f(); void (*p)() = reinterpret_cast<void(*)()>(f); p(); // undefined

To get versionName and versionCode of current build of your application you should query Android's package manager. try { // Reference to Android's package manager PackageManager packageManager = this.getPackageManager(); // Getting package info of this application PackageInfo...

System.assert can be used to check that a boolean expression evaluates to true: System.assert(Service.isActive()); System.assert(!Service.getItems().isEmpty(), 'items should not be empty'); System.assertEquals and System.assertNotEquals can be used to check equality of two values. The expected ...

class Example def example_method :example end def subexample_method :example end def not_missed_method :example end def method_missing name return :example if name == :missing_example_method return :example if name == :missing_subexample_method ...

There are two ways to interrupt messages. Use method_missing to interrupt any non defined message. Define a method in middle of a chain to intercept the message After interrupting messages, it is possible to: Reply to them. Send them somewhere else. Modify the message or its result. ...

To String Swift let string = String(NSString(data: data, encoding: NSUTF8StringEncoding)) //assuming data is a valid NSData object Objective-C NSString *string = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding]; //assuming data is a valid NSData object [string release]; T...

This builds on the previous example of the Greeter class which has two dependencies, IGreetingProvider and IGreetingWriter. The actual implementation of IGreetingProvider might retrieve a string from an API call or a database. The implementation of IGreetingWriter might display the greeting in the ...

Dependency injection means writing classes so that they do not control their dependencies - instead, their dependencies are provided to them ("injected.") This is not the same thing as using a dependency injection framework (often called a "DI container", "IoC container&quo...

This is an example of how to implement custom parameter converters for JAX-RS endpoints. The example shows two classes from Java 8's java.time library. @Provider public class ParamConverters implements ParamConverterProvider { @Override public <T> ParamConverter<T> getConverter...

Given a list: li = [1,2,3,4,5] we can filter a list with a predicate using filter :: (a -> Bool) -> [a] -> [a]: filter (== 1) li -- [1] filter (even) li -- [2,4] filter (odd) li -- [1,3,5] -- Something slightly more complicated comfy i = notTooLarg...

var bufferBlock = new BufferBlock<int>(new DataflowBlockOptions { BoundedCapacity = 1000 }); var cancellationToken = new CancellationTokenSource(TimeSpan.FromSeconds(10)).Token; var producerTask = Task.Run(async () => { var random = new Random(); while (!cancellati...

The @switch annotation tells the compiler that the match statement can be replaced with a single tableswitch instruction at the bytecode level. This is a minor optimization that can remove unnecessary comparisons and variable loads during runtime. The @switch annotation works only for matches again...

Most KVO and KVC functionality is already implemented by default on all NSObject subclasses. To start observing a property named firstName of an object named personObject do this in the observing class: [personObject addObserver:self forKeyPath:@"firstName" ...

Objective-C NSURL *url = [[NSURL alloc] initWithString:@"YOUR URL"]; // url can be remote or local AVPlayer *player = [AVPlayer playerWithURL:url]; // create a player view controller AVPlayerViewController *controller = [[AVPlayerViewController alloc] init]; [self presentViewC...

Basically you can use type inference whenever it is possible. However, be careful when combining Option Infer Off and Option Strict Off, as this can lead to undesired run-time behavior: Dim someVar = 5 someVar.GetType.ToString() '--> System.Int32 someVar = "abc" someVar.GetType.To...