NSMutableArray *arr1 = [[NSMutableArray alloc]initWithObjects:@"1",@"2",@"3", nil];

        NSMutableArray *arr2 = [[NSMutableArray alloc]init];

      轉(zhuǎn)換倒敘 

     arr2 = (NSMutableArray*)[[arr1 reverseObjectEnumerator]allObjects];