如何確保一個字符串只包含a-z和A-Z字符？

Question

我輸入的用戶名稱只需要輸入a-z和A-Z。我想驗證名稱，請幫助我。

在此先感謝

Answer 1

NSCharacterSet *nonAlphabetChars = [[NSCharacterSet characterSetWithCharactersInString:@"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"] invertedSet]; 
if ([myString rangeOfCharacterFromSet:nonAlphabetChars].location == NSNotFound) { 
    // myString is valid 
    ... 
} else { 
    // myString contains at least one invalid character 
    ... 
} 

Answer 2

你可以做這樣的事情：

NSCharacterSet *allowed = [NSCharacterSet alphanumericCharacterSet]; 
NSCharacterSet *forbidden = [allowed invertedSet]; 
NSRange range = [string rangeOfCharacterFromSet:forbidden]; 
BOOL isValid = (range.location == NSNotFound); 

的alphanumericCharacterSet可能不是你想要什麼，看NSCharacterSet更多選項。