Tutorial by Examples: t

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...

Given a list comprehension you can append one or more if conditions to filter values. [<expression> for <element> in <iterable> if <condition>] For each <element> in <iterable>; if <condition> evaluates to True, add <expression> (usually a function...

An array can be initialized empty: // An empty array $foo = array(); // Shorthand notation available since PHP 5.4 $foo = []; An array can be initialized and preset with values: // Creates a simple array with three strings $fruit = array('apples', 'pears', 'oranges'); // Shorthand no...

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); ...

The use construct is used to import variables into the anonymous function's scope: $divisor = 2332; $myfunction = function($number) use ($divisor) { return $number / $divisor; }; echo $myfunction(81620); //Outputs 35 Variables can also be imported by reference: $collection = []; $a...

print_r() - Outputting Arrays and Objects for debugging print_r will output a human readable format of an array or object. You may have a variable that is an array or object. Trying to output it with an echo will throw the error: Notice: Array to string conversion. You can instead use the print_r...

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...

A single case in a switch statement can match on multiple values. let number = 3 switch number { case 1, 2: print("One or Two!") case 3: print("Three!") case 4, 5, 6: print("Four, Five or Six!") default: print("Not One, Two, Three, Four, F...

A single case in a switch statement can match a range of values. let number = 20 switch number { case 0: print("Zero") case 1..<10: print("Between One and Ten") case 10..<20: print("Between Ten and Twenty") case 20..<30: print("Be...

var x = true, y = false; AND This operator will return true if both of the expressions evaluate to true. This boolean operator will employ short-circuiting and will not evaluate y if x evaluates to false. x && y; This will return false, because y is false. OR This operator wil...

Python lists are zero-indexed, and act like arrays in other languages. lst = [1, 2, 3, 4] lst[0] # 1 lst[1] # 2 Attempting to access an index outside the bounds of the list will raise an IndexError. lst[4] # IndexError: list index out of range Negative indices are interpreted as countin...

dictionary = {"Hello": 1234, "World": 5678} print(dictionary["Hello"]) The above code will print 1234. The string "Hello" in this example is called a key. It is used to lookup a value in the dict by placing the key in square brackets. The number 1234 is ...

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...

When run from the CLI, the constants STDIN, STDOUT, and STDERR are predefined. These constants are file handles, and can be considered equivalent to the results of running the following commands: STDIN = fopen("php://stdin", "r"); STDOUT = fopen("php://stdout", "...

The exit construct can be used to pass a return code to the executing environment. #!/usr/bin/php if ($argv[1] === "bad") { exit(1); } else { exit(0); } By default an exit code of 0 will be returned if none is provided, i.e. exit is the same as exit(0). As exit is not a ...

The dict() constructor can be used to create dictionaries from keyword arguments, or from a single iterable of key-value pairs, or from a single dictionary and keyword arguments. dict(a=1, b=2, c=3) # {'a': 1, 'b': 2, 'c': 3} dict([('d', 4), ('e', 5), ('f', 6)]) # {'d': 4, 'e': ...

Operands of the abstract equality operator are compared after being converted to a common type. How this conversion happens is based on the specification of the operator: Specification for the == operator: 7.2.13 Abstract Equality Comparison The comparison x == y, where x and y are values, prod...

When both operands are numeric, they are compared normally: 1 < 2 // true 2 <= 2 // true 3 >= 5 // false true < false // false (implicitly converted to numbers, 1 > 0) When both operands are strings, they are compared lexicographically (according to alphabeti...

Operator != is the inverse of the == operator. Will return true if the operands aren't equal. The javascript engine will try and convert both operands to matching types if they aren't of the same type. Note: if the two operands have different internal references in memory, then false will be ret...

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...