第六天:循环
https://www.hackingwithswift.com/100/swiftui/6
for in
let platforms = ["iOS", "macOS", "tvOS", "watchOS"]
for os in platforms {
print("Swift works great on \(os).")
}
for i in 1...12 {
print("5 x \(i) is \(5 * i)")
}
for i in 1..<5 {
print("Counting 1 up to 5: \(i)")
}
for _ in 1...5 {
lyric += " hate"
}
1...12
是包含1和12的ClosedRange
,1..<5
是不包含5的Range
。
如果需要特定的step
,使用stride
函数。
for radians in stride(from: 0.0, to: .pi * 2, by: .pi / 2) {
let degrees = Int(radians * 180 / .pi)
print("Degrees: \(degrees), radians: \(radians)")
}
while
var countdown = 10
while countdown > 0 {
print("\(countdown)…")
countdown -= 1
}
print("Blast off!")
break & continue
break
退出循环;continue
跳过本次循环