Tutorial by Examples: i

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...

It is often necessary to generate a new array based on the values of an existing array. For example, to generate an array of string lengths from an array of strings: 5.1 ['one', 'two', 'three', 'four'].map(function(value, index, arr) { return value.length; }); // → [3, 3, 5, 4] 6 ['one...

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 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...

Alternatively, you can use the Interactive Ruby Shell (IRB) to immediately execute the Ruby statements you previously wrote in the Ruby file. Start an IRB session by typing: $ irb Then enter the following command: puts "Hello World" This results in the following console output (in...

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...

The filter() method creates an array filled with all array elements that pass a test provided as a function. 5.1 [1, 2, 3, 4, 5].filter(function(value, index, arr) { return value > 2; }); 6 [1, 2, 3, 4, 5].filter(value => value > 2); Results in a new array: [3, 4, 5] Fi...

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...

To iterate through a list you can use for: for x in ['one', 'two', 'three', 'four']: print(x) This will print out the elements of the list: one two three four The range function generates numbers which are also often used in a for loop. for x in range(1, 6): print(x) The res...

123.5.to_s #=> "123.5" String(123.5) #=> "123.5" Usually, String() will just call #to_s. Methods Kernel#sprintf and String#% behave similar to C: sprintf("%s", 123.5) #=> "123.5" "%s" % 123.5 #=> "123.5" "%d&quot...

"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 ...