[iOS / Swift] 103. Loops

103. Loops

for문

• 범위 연산자

    var numberArray = [Int](repeating: 0, count: 5)
    for i in 0..<numberArray.count {
        numberArray[i] = i
    }
  
    또는
  
    for i in 0...numberArray.count - 1 {
        numberArray[i] = i
    }

• for-in

    var numberArray = [1,2,3,4,5]
    for value in numberArray {
        print(value)
    }

• forEach

    var numberArray = [1,2,3,4,5]
    numberArray.forEach {
        print($0)
    }

• 2차원 배열에 저장할 때

    var arr = Array(repeating: Array(repeating: 0, count: 5), count: 5)
    for i in 0..<arr.count {
        for j in 0..<arr.count {
            arr[i][j] = 1
        }
    }

• Array 역추적

    let string = "hello world"
    let stringArray = Array(string)
  
    for char in stringArray.reversed() {
        print(char)
    }
  
    또는
  
    for idx in stride(from: stringArray.count - 1, to: -1, by: -1) {
        print(stringArray[idx])
    }
  
    또는
  
    stringArray.reversed().forEach {
        print($0)
    }

---

while문

• 일반 조건문

    while i > 0 {
        ...
    }

• 무한 루프

    while true {
        ...
    }