Swift Memo

Swift Memo
This memo is for Swift learning memo.
This is from Swift Guide Tour

Memo list

• Variable
• Method
• Class
• Array, Dictionary
• Power up switch
• Access
• Others
• For, each

Variable

let is constant, never changed.
var is variable, you change value including type.

let a = 10
var b = 10

Optional

This is good example from Apple Developer

let possibleString: String? = "An optional string."
let forcedString: String = possibleString! // requires an exclamation mark
 
let assumedString: String! = "An implicitly unwrapped optional string."
let implicitString: String = assumedString // no need for an exclamation mark

? : Optional nil is fine
! : nil isn’t fine

Optional var is wrapped variable, you can’t use directly, and you need to unwrap to add ! after var name.

a!.test()   // Forced unwrap(if nil, happens runtime error)
a?.test()   // Optional unwrap(if nil, returns nil)

var a : Int?   // Optional, default is nil
var b : Int    // Not Optional, no initiallization
var c: Optional<Int> // Optional

Method

func resStr() -> String {
   return "Hello"
}
    
func updatenum(vals : [Int]) -> (num1: Int, num2: Int) {
   var num1 : Int! = vals.count
   var num2 : Int! = vals.first
   return(num1, num2)
}
    
func sum(numbers: Int...) -> Int {
   var total = 0;
   for number in numbers {
      total += number
   }
   return total
}
    
func resFunc() -> (Int -> String) {
   func resStr(number: Int) -> String {
      return  String(number)
   }
   return resStr
}

Return method method.

Class

No template from XCode?

class

import Foundation

class Sample {
    var num = 0   
    func resStr() -> String {
        return "Hello"
    }

    class func staticm() -> String {  // static
        return "I am static"
    }
}

var sample = Sample()
sample.num = 3
println(sample.num)
let str = sample.resStr()
println(str)

* If you want to use class as Framework, you should add public.

constructor

override public init() {
   super.init()
}

Array, Dictionary

Sample

func dictarrayTest() {
   var arrays = ["Yoona", "Sooyong", "Taeyon"]
   var dics = ["1" : "Yoona", "2" : "Taeyeon"]
        
   println(dics["1"])
   println(arrays[0])
        
   // Empty
   let emptyArray = [String]()
   let emptyDictionary = [String: String]()
   let emptyArray2 = []
   let emptyDic = [:]
        
   var mutableArray = [String]()
   mutableArray.append("Yoona")
   println(mutableArray[0])
   var mutableDic = [String : String]()
   let value : String! = "yoona"
   mutableDic.updateValue(value, forKey: "1")
   println(dics["1"])

   for (key,value) in mutableDic {
            println("Key:" + key + "Value:" + value)
   }
}

Result

Optional("Yoona")
Yoona
Yoona
Optional("Yoona")
Key:1Value:yoona

Power up switch

We can evaluate String class.
Also use method. Like if else

 func powerSwitch(name : String) {
        switch name {
        case "Yoona":
            println("You are Yoona")
        case "A", "S":
            println("You use Code Name")
        case let x where x.hasPrefix("Mr."):
            println("Mr.")
        default:
            println("others")
        }
}

Access

Use .

let skView = self.view as SKView
skView.showsFPS = true
skView.showsNodeCount = true

Others

No header.

For, each

for touch: AnyObject in touches {
}

for var i=0; i < 10; i++ {
}