How to “flatten” a multi-dimensional array to simple one in PHP?

Question

It\'s probably beginner question but I\'m going through documentation for longer time already and I can\'t find any solution. I thought I could use implode for each dimensio

Answer 1

If you're okay with loosing array keys, you may flatten a multi-dimensional array using a recursive closure as a callback that utilizes array_values(), making sure that this callback is a parameter for array_walk(), as follows.

The one drawback of the preceding example is that it involves writing far more code than the following solution which uses array_walk_recursive() along with a simplified callback:

See live code

This example seems preferable to the previous one, hiding the details about how values are extracted from a multidimensional array. Surely, iteration occurs, but whether it entails recursion or control structure(s), you'll only know from perusing array.c. Since functional programming focuses on input and output rather than the minutiae of obtaining a result, surely one can remain unconcerned about how behind-the-scenes iteration occurs, that is until a perspective employer poses such a question.