过滤掉字符串中的数字和汉字

- (NSString *)filterWithString:(NSString *)str

{
    NSString *regex = @"[^a-zA-Z0-9\u4e00-\u9fa5]";
    return   [str stringByReplacingOccurrencesOfString:regex withString:@"" options:NSRegularExpressionSearch range:NSMakeRange(0, str.length)];
}

一个更6 的黑科技

//过滤字符砖中的数字
- (NSString *)filterNmuberWithString:(NSString *)str
{
    NSMutableString * mutableStr = [NSMutableString stringWithString:str];
    
    NSString *newString = [[mutableStr componentsSeparatedByCharactersInSet:
                            [[NSCharacterSet letterCharacterSet] invertedSet]] componentsJoinedByString:@""];
    return newString;
}