灵活的 switch

灵活的 switch

　　Swift 中的switch支持各种各样的比较操作：

let vegetable = "red pepper" switch vegetable {
case celery":
    let vegetableComment = Add some raisins and make ants on a log.cucumber",watercressThat would make a good tea sandwich.case let x where x.hasSuffix (pepper):
    let vegetableComment = Is it a spicy \(x)?defaultEverything tastes good in soup.
}  

　　其它循环本文来自www.itxxz.com

　　for-in除了遍历数组也可以用来遍历字典：

let interestingNumbers = [
    Prime": [2,128)">3,128)">5,128)">7,128)">11,128)">13],Fibonacci1,128)">8Square4,128)">9,128)">16,128)">25var largest = 0 for (kind,numbers) in interestingNumbers {
    for number  numbers {
        if number > largest {
            largest = number
        }
    }
}
largest  

while循环和do-while循环：本文来自www.itxxz.com

var n = 2 while n < 100 {
    n = n * 2
}
n

var m = do {
    m = m * 
} while m < 
m  

　　Swift 支持传统的for循环，此外也可以通过结合..（生成一个区间）和for-in实现同样的逻辑。

var firstForLoop = for i in 0..3 { firstForLoop += i } firstForLoop var secondForLoop = for var i = 0; i < 3; ++i { secondForLoop += 1 } secondForLoop