Swift Basics

SpriteKit is a games library/framework for the Swift programming language. Swift is an object oriented programming language so has a familiar structure but its syntax is different in a number of ways. This page covers the basics of the Swift syntax for a number of standard coding concepts. It doesn’t go in to any depth, it assumes you know these concepts from Java (or another OOP language), it just shows the syntax.

Variables

Variables in Swift are created using the var keyword. The var keyword tells the compiler the value is a variable and can be changed (it will tell you off if you create a var and don’t later change it!). You don’t need to specify the variable type but you can if you wish.

Without specifying type it is simply var myString = "hello"

If you want to create a constant then use let instead of var.

let pi = 3.1415

Maths

Mathematical operations are as you would expect =, -, /, *, +=, -=, ++, --

Conditional Statements

if

var myTestNo = 12

if myTestNo < 30 {
  print("less than 30")
} else if myTestNo < 50 {
  print("greater than 29 but less than 50")
} else {
  print("fifty or more")
}

switch

var index = 3

switch index: {
  case 1: 
    print("1")
  case 2,5:
    print("2 or 5")
  default:
    print("default case")
}

Arrays

var fruitList = ["apple", "orange", "banana", "pear"]

fruitList[0] = "watermelon"
print (fruitList[1])

Loops

For In Loop

let employees = ["Andy", "Bob", "Chuck"]
for emp in employees {
  print(emp)
}

For Numeric

for index in 1..5 {
  print(index)
}

for index in 1..<8 {
  print(index)
}

While

var i = 1
while i < 5 {
  print(i)
  i += 1
}

Functions

func hello() {
  print("hello")
}

hello()

Passing in parameters

func hello(name: String, age: Int) {
  print("hello ", name)
  print("you are ", age)
}

hello(name: "Andy", age: 21)

Returning values

func hello(name: String, age: Int) -> String {
  print("hello ", name)
  print("you are ", age)
  return "Aye Right"
}

let response = hello(name: "Andy", age: 21)

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