In my opinion if you will definitely go deep through of using arrays
i suggest using array_key_exists() just accompanied it with some usefull array functions
just like array_filter() . Also the fact that array functions are created is because of arrays and ease of use isset() would be having his best place to use as e.g checking variable existence. . OR else theres a lot of more functions to explore for arrays use out there.
But after all it would be truly depends on you what result are you trying to expect either you want an array() with NULL or not.
