rangeOfCharacterFromSet究竟做了什么？

Question

NSString *foo = @"  x "; 
    NSRange r = [foo rangeOfCharacterFromSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]]; 
    NSLog(@"foo range = %d,%d",r.location, r.length); 

结果为 “foo范围= 0,1”

所以将它曾经返回一个长度> 1？

Answer 1

请参阅the documentation for that method和for the more general method it's implemented with。