Tutorial by Examples: constant

Program units often make use of literal constants. These cover the obvious cases like print *, "Hello", 1, 1.0 Except in one case, each literal constant is a scalar which has type, type parameters and value given by the syntax. Integer literal constants are of the form 1 -1 -1_1 ...

As the static keyword is used for accessing fields and methods without an instantiated class, it can be used to declare constants for use in other classes. These variables will remain constant across every instantiation of the class. By convention, static variables are always ALL_CAPS and use unders...

You can declare multiple constants within the same const block: const ( Alpha = "alpha" Beta = "beta" Gamma = "gamma" ) And automatically increment constants with the iota keyword: const ( Zero = iota // Zero == 0 One // One == 1...

Python's string module provides constants for string related operations. To use them, import the string module: >>> import string string.ascii_letters: Concatenation of ascii_lowercase and ascii_uppercase: >>> string.ascii_letters 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQ...

User is an ActiveRecord or Mongoid class. Replace User with any Rails class in your project (even something like Integer or Array) my_string = "User" # Capitalized string # => 'User' my_constant = my_string.safe_constantize # => User my_constant.all.count # => 18 my...

This example will not work because the string passed in isn't recognized as a constant in the project. Even if you pass in "array", it won't work as it isn't capitalized. my_string = "not_a_constant" # => 'not_a_constant' my_string.safe_constantize # => nil my_s...

R has a number of build in constants. The following constants are available: LETTERS: the 26 upper-case letters of the Roman alphabet letters: the 26 lower-case letters of the Roman alphabet month.abb: the three-letter abbreviations for the English month names month.name: the English names fo...

You can use gradle to have BuildConfig constants and res values on a per flavor basis. Just add the value to the flavor you want to support. android { defaultConfig { resValue "string", "app_name", "Full App" buildConfigField "boolean",...

Arrays can be used as plain constants and class constants from version PHP 5.6 onwards: Class constant example class Answer { const C = [2,4]; } print Answer::C[1] . Answer::C[0]; // 42 Plain constant example const ANSWER = [2,4]; print ANSWER[1] . ANSWER[0]; // 42 Also from versi...

VBA defines a number of string constants for special characters like: vbCr : Carriage-Return 'Same as "\r" in C style languages. vbLf : Line-Feed 'Same as "\n" in C style languages. vbCrLf : Carriage-Return & Line-Feed (a new-line in Windows) vbTab: Tab Character vbNul...

Const appName As String = "The App For That"

Giving this enumeration as Example: enum Compass { NORTH(0), EAST(90), SOUTH(180), WEST(270); private int degree; Compass(int deg){ degree = deg; } public int getDegree(){ return degree; } } In Java an enum class is like any other c...

let mySwitch: UISwitch = { view.addSubview($0) $0.addTarget(self, action: "action", forControlEvents: .TouchUpInside) return $0 }(UISwitch())

Headers may be used to declare globally used read-only resources, like string tables for example. Declare those in a separate header which gets included by any file ("Translation Unit") which wants to make use of them. It's handy to use the same header to declare a related enumeration to ...

Constants in Go may be typed or untyped. For instance, given the following string literal: "bar" one might say that the type of the literal is string, however, this is not semantically correct. Instead, literals are Untyped string constants. It is a string (more correctly, its default ...

In an enum it is possible to define a specific behavior for a particular constant of the enum which overrides the default behavior of the enum, this technique is known as constant specific body. Suppose three piano students - John, Ben and Luke - are defined in an enum named PianoClass, as follows:...

A typeglob *foo holds references to the contents of global variables with that name: $foo, @foo, $foo, &foo, etc. You can access it like an hash and assign to manipulate the symbol tables directly (evil!). use v5.10; # necessary for say our $foo = "foo"; our $bar; say ref *foo{SCAL...

angular .module('MyApp', []) .constant('VERSION', 1.0); Your constant is now declared and can be injected in a controller, a service, a factory, a provider, and even in a config method: angular .module('MyApp') .controller('FooterController', function(VERSION) { this.version = V...

MY_CONSTANT = "Hello, world" # constant Constant = 'This is also constant' # constant my_variable = "Hello, venus" # not constatn Constant name start with capital letter. Everything that start with capital letter are considered as constant in Ruby. So class and module are al...

MY_CONSTANT = "Hello, world" MY_CONSTANT = "Hullo, world" The above code results in a warning, because you should be using variables if you want to change their values. However it is possible to change one letter at a time in a constant without a warning, like this: MY_CONST...