NSMutableArray *arr1 = [NSMutableArray arrayWithObjects:@"aa",@"bb",@"cc",@"dd",@"ee",@"ff",@"gg",@"a",@"b",@"c",@"d",@"e",@"f",nil];
NSMutableArray *arr2 = [[NSMutableArray alloc] init];
NSMutableArray *arr3 = [[NSMutableArray alloc] init];
for (int i = 0; i < [arr1 count]; i++) {
for (int j = 0 ; j < 3; j++) {
[arr2 addObject:[arr1 firstObject]];//将a1中的第一个元素添加到arr2中
[arr1 removeObjectAtIndex:0];//删除a1的第一个元素
}
[arr3 addObject:arr2];//将a2数组放入a3数组中
arr2 =[[NSMutableArray alloc] init];//将a2数组清空
}
[arr3 addObject:arr1];
NSLog(@"%@",arr3);