characterSetWithCharactersInString 写一个使用示例

NSString *letters = @"abcdefghijklmnopqrstuvwxyz"; NSCharacterSet *set = [NSCharacterSet characterSetWithCharactersInString:letters]; NSString *string = @"Hello World"; NSRange range = [string rangeOfCharacterFromSet:set]; if (range.location != NSNotFound) { NSLog(@"The string contains at least one letter from the set"); } else { NSLog(@"The string does not contain any letters from the set"); }