Tutorial by Examples: an

Parentheses are now forbidden around named parameters. The following compiles in C#5, but not C#6 5.0 Console.WriteLine((value: 23)); Operands of is and as are no longer allowed to be method groups. The following compiles in C#5, but not C#6 5.0 var result = "".Any is byte; T...

There are many ways to create arrays. The most common are to use array literals, or the Array constructor: var arr = [1, 2, 3, 4]; var arr2 = new Array(1, 2, 3, 4); If the Array constructor is used with no arguments, an empty array is created. var arr3 = new Array(); results in: [] Note...

Start by defining a Foo function that we'll use as a constructor. function Foo (){} By editing Foo.prototype, we can define properties and methods that will be shared by all instances of Foo. Foo.prototype.bar = function() { return 'I am bar'; }; We can then create an instance using the ...

Defining an Anonymous Function When a function is defined, you often give it a name and then invoke it using that name, like so: foo(); function foo(){ // ... } When you define a function this way, the Javascript runtime stores your function in memory and then creates a reference to th...

var xhttp = new XMLHttpRequest(); xhttp.onreadystatechange = function () { if (xhttp.readyState === XMLHttpRequest.DONE && xhttp.status === 200) { //parse the response in xhttp.responseText; } }; xhttp.open("GET", "ajax_info.txt", true); xhttp.send(...

echo and print are language constructs, not functions. This means that they don't require parentheses around the argument like a function does (although one can always add parentheses around almost any PHP expression and thus echo("test") won't do any harm either). They output the string r...

Unlike in languages like Python, static properties of the constructor function are not inherited to instances. Instances only inherit from their prototype, which inherits from the parent type's prototype. Static properties are never inherited. function Foo() {}; Foo.style = 'bold'; var foo = ne...

The map function is the simplest one among Python built-ins used for functional programming. map() applies a specified function to each element in an iterable: names = ['Fred', 'Wilma', 'Barney'] Python 3.x3.0 map(len, names) # map in Python 3.x is a class; its instances are iterable # Out: &...

ConstantsDescriptionApproximateMath.EBase of natural logarithm e2.718Math.LN10Natural logarithm of 102.302Math.LN2Natural logarithm of 20.693Math.LOG10EBase 10 logarithm of e0.434Math.LOG2EBase 2 logarithm of e1.442Math.PIPi: the ratio of circle circumference to diameter (π)3.14Math.SQRT1_2Square ro...

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...

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...

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...

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", "...

Program options can be handled with the getopt() function. It operates with a similar syntax to the POSIX getopt command, with additional support for GNU-style long options. #!/usr/bin/php // a single colon indicates the option takes a value // a double colon indicates the value may be omitted ...

At the command line, first verify that you have Git installed: On all operating systems: git --version On UNIX-like operating systems: which git If nothing is returned, or the command is not recognized, you may have to install Git on your system by downloading and running the installer. See...

"123.50".to_i #=> 123 Integer("123.50") #=> 123 A string will take the value of any integer at its start, but will not take integers from anywhere else: "123-foo".to_i # => 123 "foo-123".to_i # => 0 However, there is a difference when ...

1/2 #=> 0 Since we are dividing two integers, the result is an integer. To solve this problem, we need to cast at least one of those to Float: 1.0 / 2 #=> 0.5 1.to_f / 2 #=> 0.5 1 / Float(2) #=> 0.5 Alternatively, fdiv may be used to return the floating point result of di...

The JSONSerialization class is built into Apple's Foundation framework. 2.2 Read JSON The JSONObjectWithData function takes NSData, and returns AnyObject. You can use as? to convert the result to your expected type. do { guard let jsonData = "[\"Hello\", \"JSON\"]&q...