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 range = 0,1”

所以它会返回长度＆gt; 1？

Answer 1

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