Swift 基本構文の備忘録

備忘録

よく忘れがちな基本構文をメモメモ

定数

let number1 = 12
let number2 = 24

let number3 = number1 + number2

print ("\(number3)") // ---> 36

イメージの挿入

let image = UIImage(named:"imagename")

let imageView = UIImageView(image: image)

変数

var sr = "Hello, playground"
sr = "Hello Swift"

let st = "Hello!"

• 文字列

var member1: String = "Yamada Taro"
var member2 = "yamada"
var member3: String
member3 = "Taro"

• 整数

var age1: Int = 26
var age2 = 26
var age3: Int
age3 = 25

• Double 64 bit の浮動小数点数

var height1: Double = 182.4
var height2 = 182.4
var height3: Double
height3 = 183.4

• Float 32bit の浮動小数点数

var weight1: Float = 88.3
var weight2 = 88.3
var weight3: Float
weight3 = 33.2

• 真偽値

var isMan1: Bool = true
var isMan2 = true
var isMan3: Bool
isMan3 = false

• 代入

var a: Int
a = 2 * 9

Intの余りの計算では変数がDoubleなど整数でないとエラーになる．

String ()

let num1: Int = 86
let sNum1: String = String(num1)

print(sNum1)

• description

let num2: Int = 65
let sNum2: String = num2.description

print (sNum2)

let num3: Int = 39
let sNum3: String = "\(num3)"

print(sNum3)

String -> Int

• Int ()

let Str1: String = "94"
let nStr1: Int = Int (Str1)!

print (nStr1)

let Str2: String = "98abc"
let nStr2 = Int(Str2)

print(nStr2 as Any)

let Str3: String = "108abc"
if let nStr3 = Int(Str3){
    print(nStr3)
}
else{
    print ("error")
}

• NumberFormatter

let Str4 = "78"
let nStr4 = NumberFormatter().number(from: Str4) as! Int
print(nStr4)

Double -> String

• String()

let num4: Double = 86.87
let sNum4: String = String(num4)

print (sNum4)

• desciption

let num5: Double = 65.989
let sNum5: String = String(num5)

print (sNum5)

let num6: Double = 8.001
let sNum6: String = "\(num6)"

print (sNum6)

String -> Double

• Double()

let Str5: String = "94.765"
let nStr5: Double = Double(Str5)!

• Darwin.atof

let Str6: String = "10.59"
let nStr6: Double = atof(Str6)

Int <-> Double

• Double から Int

let dNum1:Double = 3.14
let iNum1:Int = Int(dNum1)

print(iNum1)

Int から Double

let iNum2:Int = 37
let dNum2:Double = Double(iNum2)

print(dNum2)

　最後に

とりあえず，パート1である．
そのうち続きも備忘録で書くかも