Convert multi-dimensional array into matrix-like array

Question

I have the following array:

$array = array(
    array("2018","2019"),
    "Jan",
    array("France","Germany")
);

I need a matrix that crosses all the elements of the array; e.g:

array(
    array("2018","Jan","France"),
    array("2018","Jan","Germany"),
    array("2019","Jan","France"),
    array("2019","Jan","Germany")
);

meaning, 2 x 2 x 1 arrays

but this can be that I have more elements that are or are not arrays then:

$array = array(
    array("2018","2019"),
    "Jan",
    array("France","Germany"),
    array("prod1","prod2","prod3"),
    'Act'
);

In this case I would get 2 x 2 x 1 x 4 x 1 arrays in the end.

Any idea on how to achieve this?

not yet, I am rather looking for an orientation thus. I wonder whether loops would work since the number of arrays can be variable — laloune
– laloune, Commented Aug 7, 2017 at 14:14
You can loop through the main array and detect the whether each element is array. Maybe you can try a recursion.... — lvil
– lvil, Commented Aug 7, 2017 at 14:15
I think recursion is the easiest solution. Have a look here stackoverflow.com/questions/8567082/… this might help you — ᴄʀᴏᴢᴇᴛ
– ᴄʀᴏᴢᴇᴛ, Commented Aug 7, 2017 at 14:17
Possible duplicate of How to generate in PHP all combinations of items in multiple arrays — ᴄʀᴏᴢᴇᴛ
– ᴄʀᴏᴢᴇᴛ, Commented Aug 7, 2017 at 14:19

Sarkouille · Accepted Answer · 2017-08-07 14:37:30Z

1

Is that what you are looking for ?

$dst = array(array());
foreach ($array as $idx => $val) {
    foreach ($dst as $tmp_idx => $tmp_array) {
        if (is_array($val)) {
            foreach ($val as $sub_idx => $sub_val) {
                $dst[] = array_merge($dst[$tmp_idx], array(count($dst[$tmp_idx]) => $sub_val));
            }
        } else {
            $dst[] = array_merge($dst[$tmp_idx], array(count($dst[$tmp_idx]) => $val));
        }
        unset($dst[$tmp_idx]);
    }
}

I declare the array with an empty array in it.
A first foreach iterates through the main array to access all the categories, whatever their number.
A second foreach iterates through the result array.
A third foreach - or not, depending if the category contains several or a single entry - iterates through each entry of the current category and merges an array containing only that current category in the result currently iterated on (from $dst). The merge is pushed into the result array. The result stored in $dst are assumed to be temporary and will be copied and completed with each new value, making them progressively contain one entry from each category.
At the end of each iteration on $dst, the current temporary result is removed from the array since it has no purpose : if the foreach iterated on it, that means that it was incomplete.
At the end, the only entries in $dst that remain are these who weren't iterated on, meaning that every entry from each category were considered when they were created, meaning that they are complete.
I'm available for any clarification may the need arise.

edited Aug 7, 2017 at 14:37

answered Aug 7, 2017 at 14:24

Sarkouille

1,2319 silver badges16 bronze badges

Sign up to request clarification or add additional context in comments.

6 Comments

Sarkouille Over a year ago

I guess it can be optimised, especially regarding the unset() part, but I haven't slept for a day and a half and answer from work, I believe my brains are a little off.

ᴄʀᴏᴢᴇᴛ Over a year ago

While this code may answer the question, providing additional context regarding why and/or how this code answers the question improves its long-term value.

Sarkouille Over a year ago

@ᴄʀᴏᴢᴇᴛ I fully agree with that, I'm definitely dizzy, my apologies.

laloune Over a year ago

this is definitely what I am looking for. Thanks a lot. I will analyze it further to understand what it does step by step.

laloune Over a year ago

gee thanks a bunch ksjohn for this complete explanation! this brings a lot of value added

|

Collectives™ on Stack Overflow

Convert multi-dimensional array into matrix-like array

1 Answer 1

6 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

6 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related