截取2个指定字符串中的字符串

NSString *string = @"abavavasdsvx,as.dsf/,.[abcdefghijklmn]dgdfg";
NSRange start = [string rangeOfString:@"["];
NSRange end = [string rangeOfString:@"]"];
NSString *sub = [string substringWithRange:NSMakeRange(start.location, end.location-start.location+1)];
NSLog(@"sub=%@",sub);