Appendix B. Swift syntax cheat sheets

var aVariable = 0
let aConstant = 0

var aString: String
var aBool: Bool
var aInt: Int
var aDouble: Double

var bString = "A String!"
var bBool = true
var bInt = 3
var bDouble = 3.0

var cDouble: Double = 3

var dDouble = Double(3)

var score = 0 {
  willSet {
    // Score will be updated
  }
  didSet {
    // Score was updated
  }
}

var message = "You scored\(score)"

var emptyArray: [String] = []
var arrayOfInts = [3, 1, 2, 5]
arrayOfInts.append(4)

var emptyDictionary: [String: String] = [:]
var dict = ["A": 1, "B": 2, "C": 3]
dict["D"] = 4

var emptySet: Set<String> = [] //empty Set
var setOfStrings: Set = ["A", "B", "C"]
setOfStrings.insert("D")

let closedRange = 1...3 // include 3
let halfOpenRange = 1..<3 // exclude 3

for index in 1...3 {
    print("\(index) banana")
}

let distances = [3, 1, 2, 5, 4]
var returnDistances: [Int] = []
for distance in distances {
    returnDistances.append(distance * 2)
}

print(distances.map( { $0 * 2 } ))
// [6,2,4,10,8]
print(distances.filter( { $0 >= 3 } ))
// [3,5,4]
print(distances.reduce(0, {$0 + $1} ))
// 15
print(distances.sorted(by: { $0 > $1 } ))
// [5,4,3,2,1]

var card1: (Int, String)
card1 = (7, "♥")
card1.0 = 3
print("\(card1.0) of \(card1.1)")
// The 3 of ♥

enum AEnum {
    case aCase
    case bCase
}
let aEnum = AEnum.bCase

func aFunc() {
    // Do something
}