如何确保一个字符串只包含a-z和A-Z字符？

Question

我输入的用户名称只需要输入a-z和A-Z。我想验证名称，请帮助我。

在此先感谢

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

你可以做这样的事情：

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

的alphanumericCharacterSet可能不是你想要什么，看NSCharacterSet更多选项。