我更新了Xcode
到7.3,现在我对我用来创建随机字符串的函数有一个警告.
我试图用for (i in 0 ..< len){...}
来更改for
语句,但警告变成了错误.
如何删除警告?
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
}