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Getting Started

Variable

var score = 0  // Variable
let pi = 3.14  // Constant

var greeting = "Hello"
var numberOfToys = 8
var isMorning = true

var numberOfToys: Int = 8
numberOfToys += 1

print(numberOfToys)
// prints "9"

Type Annotations

var greeting: String = "Hello"
var numberOfToys: Int = 8
var isMorning: Bool = true
var price: Double = 8.99

Arithmetic Operators

  • + Add
  • - Subtraction
  • * Multiplication
  • / Division
  • % Remainder
var x = 0
x = 4 + 2 // x is now 6
x = 4 - 2 // x is now 2
x = 4 * 2 // x is now 8
x = 4 / 2 // x is now 2
x = 4 % 2 // x is now 0
  • += Adds and assigns sums
  • -= subtract and assign the difference
  • *= Multiplication and assignment
  • /= Divide and assign quotient
  • %= Divide and assign remainder

Compound Assignment Operators

var numberOfDogs = 100
numberOfDogs += 1
print("There are \(numberOfDogs) Dalmatians!")

// print: There are 101 Dalmatians!

String Interpolation

var apples = 6
print("I have \(apples) apples!")

// print: I have 6 apples!

Multi-line String

let myLongString = """
Swift?
This is my favorite language!
Yeah!
"""

Code Comments

// This line represents a comment in Swift.

/*
This is all commented out.
None will run!
*/

Form a Tuple

let player = ("Maya", 5, 150)

print(player) // ("Maya", 5, 150)
print("\(player.0): level \(player.1), \(player.2) pts") // Maya: level 5, 150 pts

Decompose Tuple

let player = (name: "Maya", level: 5)
let (currentName, curLevel) = player
print("\(currentName): level \(curLevel)")
// print: Maya: level 5

Special Comment Syntax

MARK

// MARK: -view settings

MARK can be used to display comments in the column

TODO

// TODO: update logic to accommodate data changes

TODO is used to display reminders of things that need to be done

FIXME

// FIXME: Fix buggy behavior when making changes to existing entries

FIXME is used to display reminders about things that need to be fixed

Comments