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The ternary operator is used for inline conditional expressions. It is best used in simple, concise operations that are easily read. The order of the arguments is different from many other languages (such as C, Ruby, Java, etc.), which may lead to bugs when people unfamiliar with Python's "s...

Lens operators have useful variants that operate in stateful contexts. They are obtained by replacing ~ with = in the operator name. (+~) :: Num a => ASetter s t a a -> a -> s -> t (+=) :: (MonadState s m, Num a) => ASetter' s a -> a -> m () Note: The stateful variants ar...

Here is some sample XML against which example XPaths can be written: <r> <e a="1"/> <f a="2" b="1">Text 1</f> <f/> <g> <i c="2">Text 2</i> Text 3 <j>Text 4</j> </g&gt...

For the sample XML (without namespaces): This XPath, /r/e will select this element: <e a="1"/>

A new thread separate from the main thread's execution, can be created using Thread.new. thr = Thread.new { sleep 1 # 1 second sleep of sub thread puts "Whats the big deal" } This will automatically start the execution of the new thread. To freeze execution of the main Thread, ...

Python 2.x2.3 Objects of different types can be compared. The results are arbitrary, but consistent. They are ordered such that None is less than anything else, numeric types are smaller than non-numeric types, and everything else is ordered lexicographically by type. Thus, an int is less than a st...

Any type can be declared as an array using either the dimension attribute or by just indicating directly the dimension(s) of the array: ! One dimensional array with 4 elements integer, dimension(4) :: foo ! Two dimensional array with 4 rows and 2 columns real, dimension(4, 2) :: bar ! Three...

def say_hello_to(name) puts "Hello #{name}" end say_hello_to('Charles') # Hello Charles

def greet(greeting, name) puts "#{greeting} #{name}" end greet('Hi', 'Sophie') # Hi Sophie

def make_animal_sound(sound = 'Cuack') puts sound end make_animal_sound('Mooo') # Mooo make_animal_sound # Cuack It's possible to include defaults for multiple arguments: def make_animal_sound(sound = 'Cuack', volume = 11) play_sound(sound, volume) end make_animal_so...

def welcome_guests(*guests) guests.each { |guest| puts "Welcome #{guest}!" } end welcome_guests('Tom') # Welcome Tom! welcome_guests('Rob', 'Sally', 'Lucas') # Welcome Rob! # Welcome Sally! # W...

fn main() { // Statically allocated string slice let hello = "Hello world"; // This is equivalent to the previous one let hello_again: &'static str = "Hello world"; // An empty String let mut string = String::new(); // An empty String ...

Let's say we have an interface for logging: interface Logger { function log($message); } Now say we have two concrete implementations of the Logger interface: the FileLogger and the ConsoleLogger. class FileLogger implements Logger { public function log($message) { // Append...

Generate a certificate In order to run a HTTPS server, a certificate is necessary. Generating a self-signed certificate with openssl is done by executing this command: openssl req -x509 -newkey rsa:4096 -sha256 -nodes -keyout key.pem -out cert.pem -subj "/CN=example.com" -days 3650` T...

Arrays are available in most programming languages, often using square [] or round () brackets to access the elements, e.g. Carray[6] or VBarray(6).

foo.h #ifndef FOO_DOT_H /* This is an "include guard" */ #define FOO_DOT_H /* prevents the file from being included twice. */ /* Including a header file twice causes all kinds */ /* of interesting problems.*/ /** * This is a functi...

Use of global variables is generally discouraged. It makes your program more difficult to understand, and harder to debug. But sometimes using a global variable is acceptable. global.h #ifndef GLOBAL_DOT_H /* This is an "include guard" */ #define GLOBAL_DOT_H /** * This tells ...

Basic usage: PropertyInfo prop = myInstance.GetType().GetProperty("myProperty"); // get the value myInstance.myProperty object value = prop.GetValue(myInstance); int newValue = 1; // set the value myInstance.myProperty to newValue prop.setValue(myInstance, newValue); Setting rea...

SQLiteOpenHelper is a helper class to manage database creation and version management. In this class, the onUpgrade() method is responsible for upgrading the database when you make changes to the schema. It is called when the database file already exists, but its version is lower than the one spec...

While static constructors are always called before the first usage of a type it's sometimes useful to be able to force them to be called and the RuntimeHelpers class provide an helper for it: using System.Runtime.CompilerServices; // ... RuntimeHelpers.RunClassConstructor(typeof(Foo).TypeHand...