循环 for/while

Swift 的 for-in 配合区间和集合遍历最常用。stride 控制步长，forEach 函数式遍历。

学完本章你将： 掌握 for-in、while/repeat-while、stride、forEach。

for-in 循环

swift

// 区间循环
for i in 0..<5 {
    print(i)  // 0 1 2 3 4
}

// stride（控制步长）
for i in stride(from: 0, to: 10, by: 2) {
    print(i)  // 0 2 4 6 8
}

for i in stride(from: 10, through: 0, by: -2) {
    print(i)  // 10 8 6 4 2 0
}

// 集合遍历
let names = ["小明", "小红", "小刚"]
for name in names {
    print(name)
}

// 带索引
for (index, name) in names.enumerated() {
    print("\(index): \(name)")
}

while / repeat-while

swift

// while —— 先判断
var i = 0
while i < 5 {
    print(i)
    i += 1
}

// repeat-while —— 先执行（至少一次）
var j = 0
repeat {
    print(j)
    j += 1
} while j < 0  // 执行一次

forEach

swift

names.forEach { name in
    print(name)
}

// 简写
names.forEach { print($0) }

循环 for/while

循环 for/while

for-in 循环

while / repeat-while

forEach

🛠️ 学完试试这些工具