Swift Language Variables & Properties Creating a Variable


Declare a new variable with var, followed by a name, type, and value:

var num: Int = 10

Variables can have their values changed:

num = 20 // num now equals 20

Unless they're defined with let:

let num: Int = 10 // num cannot change

Swift infers the type of variable, so you don't always have to declare variable type:

let ten = 10 // num is an Int
let pi = 3.14 // pi is a Double
let floatPi: Float = 3.14 // floatPi is a Float

Variable names aren't restricted to letters and numbers - they can also contain most other unicode characters, although there are some restrictions

Constant and variable names cannot contain whitespace characters, mathematical symbols, arrows, private-use (or invalid) Unicode code points, or line- and box-drawing characters. Nor can they begin with a number

Source developer.apple.com

var π: Double = 3.14159
var 🍎🍏: String = "Apples"