[英]Strange return value after generating random string (Swift 3)
我創建了一個方法,該方法生成並返回一個由字母和數字組成的隨機字符串,但是由於某種原因,我只能得到一個帶有數字的字符串,並且字符串的長度與我要求的接近。 已返回的字符串的一些示例:“ 478388299949939566”(插入長度為18),“ 3772919388584334”(插入長度為9),“ 2293010089409293993945”(插入長度為6)。 有人可以看到我在這里想念的嗎?
func generateRandomStringWithLength(length:Int) -> String {
let randomString:NSMutableString = NSMutableString(capacity: length)
let letters:NSMutableString = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
for index in 0...length {
let randomIndex:Int = Int(arc4random_uniform(UInt32(62)))
randomString.append("\(letters.character(at: randomIndex))")
}
return String(randomString)
}
您的問題在這里:
letters.character(at: randomIndex)
它的功能返回給定UTF-16代碼單元索引處的字符,而不僅僅是一個字符
這是我的版本,我想它會更快。
func generateRandomStringWithLength(length: Int) -> String {
var randomString = ""
let letters = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
for _ in 1...length {
let randomIndex = Int(arc4random_uniform(UInt32(letters.characters.count)))
let a = letters.index(letters.startIndex, offsetBy: randomIndex)
randomString += String(letters[a])
}
return randomString
}
generateRandomStringWithLength(length: 5)
用這個:
func generateRandomStringWithLength(length:Int) -> String {
let randomString:NSMutableString = NSMutableString(capacity: length)
let letters:NSMutableString = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
var i: Int = 0
while i < length {
let randomIndex:Int = Int(arc4random_uniform(UInt32(letters.length)))
randomString.appendString("\(Character( UnicodeScalar( letters.characterAtIndex(randomIndex))))")
i += 1
}
return String(randomString)
}
print(generateRandomStringWithLength(5))
print(generateRandomStringWithLength(10))
print(generateRandomStringWithLength(20))
print(generateRandomStringWithLength(7))
print(generateRandomStringWithLength(14))
GIrqb
nWmieQRVdk
r0It9V1xkGFRa2HVwtCw
RLIRuVI
nXnFGV2LQ3CjbD
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