2有一個數組,數組中有13個元素,先將該數組進行分組,每3個元素爲一組,分爲若干組,最後用一個數組統一管理這些分組.(要動態創建數組).

NSMutableArray *arr = [[NSMutableArray alloc] init];
        for (int i = 0; i < 15 ; i++) {
            [arr addObject:[NSString stringWithFormat:@"damo%d",i]];
        }
        NSLog(@"%@",arr);
        NSMutableArray *bigArr =  [[NSMutableArray alloc] initWithCapacity:1];
        NSMutableArray *smallArr = nil;
        for (int i = 0; i < [arr count]; i++) {
                        if (i % 3 == 0) {
                //只要讀到0 3 6 9 12 就開闢空間存儲接下來的三個元素
                smallArr = [[NSMutableArray alloc] initWithCapacity:1];
                //將小數組添加到大數組中進行管理
                [bigArr addObject:smallArr];
            }
            [smallArr addObject:[arr objectAtIndex:i]];
        }
        NSLog(@"%@",bigArr);</span>