Tutorial by Examples: me

All angles below are in radians. An angle r in radians has measure 180 * r / Math.PI in degrees. Sine Math.sin(r); This will return the sine of r, a value between -1 and 1. Math.asin(r); This will return the arcsine (the reverse of the sine) of r. Math.asinh(r) This will return the hype...

Anonymous functions can be assigned to variables for use as parameters where a callback is expected: $uppercase = function($data) { return strtoupper($data); }; $mixedCase = ["Hello", "World"]; $uppercased = array_map($uppercase, $mixedCase); print_r($uppercased); ...

Variables can be incremented or decremented by 1 using the ++ and -- operators, respectively. When the ++ and -- operators follow variables, they are called post-increment and post-decrement respectively. int a = 10; a++; // a now equals 11 a--; // a now equals 10 again When the ++ and -- ope...

Arguments are passed to the program in a manner similar to most C-style languages. $argc is an integer containing the number of arguments including the program name, and $argv is an array containing arguments to the program. The first element of $argv is the name of the program. #!/usr/bin/php p...

Place this code in a file named HelloWorld.scala: object Hello { def main(args: Array[String]): Unit = { println("Hello World!") } } Live demo To compile it to bytecode that is executable by the JVM: $ scalac HelloWorld.scala To run it: $ scala Hello When the Scala...

An enum provides a set of related values: enum Direction { case up case down case left case right } enum Direction { case up, down, left, right } Enum values can be used by their fully-qualified name, but you can omit the type name when it can be inferred: let dir = Dire...

A decorator takes just one argument: the function to be decorated. There is no way to pass other arguments. But additional arguments are often desired. The trick is then to make a function which takes arbitrary arguments and returns a decorator. Decorator functions def decoratorfactory(message): ...

Sometimes you don't want to have your function accessible/stored as a variable. You can create an Immediately Invoked Function Expression (IIFE for short). These are essentially self-executing anonymous functions. They have access to the surrounding scope, but the function itself and any internal va...

jQuery is the starting point for writing any jQuery code. It can be used as a function jQuery(...) or a variable jQuery.foo. $ is an alias for jQuery and the two can usually be interchanged for each other (except where jQuery.noConflict(); has been used - see Avoiding namespace collisions). Assumi...

Protocols may define associated type requirements using the associatedtype keyword: protocol Container { associatedtype Element var count: Int { get } subscript(index: Int) -> Element { get set } } Protocols with associated type requirements can only be used as generic constraints:...

Instead of importing the complete module you can import only specified names: from random import randint # Syntax "from MODULENAME import NAME1[, NAME2[, ...]]" print(randint(1, 10)) # Out: 5 from random is needed, because the python interpreter has to know from which resource it...

from module_name import * for example: from math import * sqrt(2) # instead of math.sqrt(2) ceil(2.7) # instead of math.ceil(2.7) This will import all names defined in the math module into the global namespace, other than names that begin with an underscore (which indicates that the wri...

Finding the minimum/maximum of a sequence of sequences is possible: list_of_tuples = [(0, 10), (1, 15), (2, 8)] min(list_of_tuples) # Output: (0, 10) but if you want to sort by a specific element in each sequence use the key-argument: min(list_of_tuples, key=lambda x: x[0]) # Sorting ...

You can't pass an empty sequence into max or min: min([]) ValueError: min() arg is an empty sequence However, with Python 3, you can pass in the keyword argument default with a value that will be returned if the sequence is empty, instead of raising an exception: max([], default=42) ...

Assigns the value of the right-hand operand to the storage location named by the left-hand operand, and returns the value. int x = 5; /* Variable x holds the value 5. Returns 5. */ char y = 'c'; /* Variable y holds the value 99. Returns 99 * (as the character 'c' is repr...

Basic Arithmetic Return a value that is the result of applying the left hand operand to the right hand operand, using the associated mathematical operation. Normal mathematical rules of commutation apply (i.e. addition and multiplication are commutative, subtraction, division and modulus are not). ...

Instead of this lambda-function that calls the method explicitly: alist = ['wolf', 'sheep', 'duck'] list(filter(lambda x: x.startswith('d'), alist)) # Keep only elements that start with 'd' # Output: ['duck'] one could use a operator-function that does the same: from operator import metho...

What can be documented? Examples of functions for various languages. A brief introduction of each tag. What is the difference between a question and a topic? Topics have a broader scope than questions; documentation topics that are asked as a question can be closed because they are too bro...

Arguments are defined in parentheses after the function name: def divide(dividend, divisor): # The names of the function and its arguments # The arguments are available by name in the body of the function print(dividend / divisor) The function name and its list of arguments are called...

Optional arguments can be defined by assigning (using =) a default value to the argument-name: def make(action='nothing'): return action Calling this function is possible in 3 different ways: make("fun") # Out: fun make(action="sleep") # Out: sleep # The argumen...