反向搜索
NSRange range2 = [@"胡明你好瓦尼卡师卡尔得" rangeOfString:@"瓦尼卡" options:NSBackwardsSearch];
指定范围进行搜索
NSRange range1 =NSMakeRange(0,10);
range1 = [@"胡明你好瓦尼卡师卡尔得" rangeOfString:@"瓦尼卡" options:NSBackwardsSearch range:range1];
NSLog(@"%@",NSStringFromRange(range1)); // 返回{5,3}