我有更新
Xcode到7.3,现在我有一个警告,我用来创建随机字符串的功能.
我试图用for(i in 0 ..< len){...}更改for语句,但是警告成为错误. 如何清除警告?
static func randomStringWithLength (len : Int) -> Nsstring { let letters : Nsstring = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMnopQRSTUVWXYZ0123456789" let randomString : NSMutableString = NSMutableString(capacity: len) for (var i=0; i < len; i += 1){ // warning let length = UInt32 (letters.length) let rand = arc4random_uniform(length) randomString.appendFormat("%C",letters.characteratIndex(Int(rand))) } return randomString }