【Swift】初心者がアプリ開発する前に覚えるSwiftの基本構文まとめ

let str: String

var str: String

var str:String = "hello world"

var str: Stringstr = S tring(3)

x += y

str1 + str2

print (こんにちは、\(name)さん")

print(true && false) //false print(true || false) //true print(!ture) //false

if judge {print(root1)}else if{print(root2)else{print(root3)}

switch myPoint {case 0:print("NG")case 1, 2, 3:print("so..so..")case 4...6:print("4~6")case 7..<10print("7~9")case let n where n > 100:print("\(n)ポイント!!!")default:print("NA")}

while count < 5 {print(count)count += 1}

for i in 0...10 {print(i)}

for i in 0...10 {if i == 5 {break}print("break test \(i)")}for i in 0...10 {if i == 5 {print("continue test \(i)")}print(i)}

let s: Optional<String> = nillet s: String? = nil

if s != nil {print(s!)}

if let value = s {print(value)}

print(str ?? "これはnilです")

var points: [Int] = [100, 50]var points = [100, 50]print(prints[0])

var fruits = [String]()fruits.append("apple")fruits += ["banana"]for str in fruits {print(str)}

var items = ("apple",100)print(items.0)print(items.1)let (product, amount) = itemsprint(product)print(amount)

let (product, _) = itemsprint(product)

初期化で名前を付けることも可能var items = (product: "apple", amount: 5)print(items.product)

var winners: Set<Int> = [3,5,8,8]var winners: Set = [3,5,8,8]print(winners) //[5,3,8]print(winners.contains(3)) //3が有るか boolwinners.insert(10) //追加winners.remove(5) //削除print(winners.count)

let s = Set<Int>()print(s.isEmpty) //true

let a: Set = [1,3,5,8]let b: Set = [3,5,8,9]print(a.union(b)) //和集合 a + bprint(a.intersection(b)) //積集合 aとbの共通print(a.subtracting(b)) //差集合 a - b

var points: Dictionary<String, Int> = ["tanaka" : 100, "satoh" : 200]points["satoh"] = 300print(points["tanaka"] ?? "NA")points["suzuki"] = 500print(points.count)for (key, value) in points {print("\(key) : \(value)")}

let d = [String: Int]()print(d.isEmpty)

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

func hello(name: String) {print("hello (name)")}print(name: "tanaka")引数と実行変数を別にする場合func hello(from name: String) {print("hello (name)")}print(from: "tanaka")

func hello(_ name: String) {print("hello (name)")}print("tanaka")

func hello(_ name: String = "satoh") {print("hello (name)")}print()

func add100(x: Int) {x += 100print(x)}

func add100(x: inout Int) {x += 100}var i = 100add100(x: &i)print(i)

class User {let name: Stringvar point: Intinit() {self.name = "tanaka"self.point = 100}}let user1: User = User()//let user1 = User()  型推論でも可能print(user1.name)user1.point = 200

class User {let name: Stringvar point: Intinit(name: String, point: Int) {self.name = nameself.point = point}}let suzuki  = User(name: "suzuki", point: 300)

class User {let name: Stringvar point: Intinit(_ name: String, _ point: Int) {self.name = nameself.point = point}}let suzuki  = User("suzuki", 300)

class User {let name: Stringvar point: Intinit(_ name: String, _ point: Int) {self.name = nameself.point = point}init() {self.name = "nanasi"self.point = 0}}let nanasi  = User()print(nanasi.name)print(nanasi.point)

class User {let name: Stringvar point: Intvar level: Int {get {return Int(point / 10)}set{if newValue >= 0 {point = newValue * 10}}}init(_ name: String, _ point: Int) {self.name = nameself.point = point}let satoh = User("satoh", 50)print(satoh.level)satoh.level = 5print(satoh.point)satoh.level = -10print(satoh.point)