PHP - Combine multiple arrays with each other - php

Question

I have been working on a tool that combines arrays containing attributes with each other.
The problem I'm having is that I don't know how to reach this goal.
I start by using the following code to decode the JSON to the arrays:
$input = '{"1":[["Red"],["Green"],["Blue"],["Purple"]],"2":[["S"],["M"],["L"]],"3":[["Wool"],["Cotton"]]}';
$arr = json_decode($input, true);
print_r($arr);
From that point, I don't know what to do. I have been trying to loop through arrays and, merging arrays but I can't find any way to reach my goal.
The following output in an array is my goal:
Red,S,Wool
Red,S,Cotton
Red,M,Wool
Red,M,Cotton
Red,L,Wool
Red,L,Cotton
Green,S,Wool
Green,S,Cotton
Green,M,Wool
Green,M,Cotton
Green,L,Wool
Green,L,Cotton
Blue,S,Wool
Blue,S,Cotton
Blue,M,Wool
Blue,M,Cotton
Blue,L,Wool
Blue,L,Cotton
Purple,S,Wool
Purple,S,Cotton
Purple,M,Wool
Purple,M,Cotton
Purple,L,Wool
Purple,L,Cotton
There is also a possibility that there will be instead of 3 like 4, 5, or more arrays with attributes.
I have found a tool which calculates this, but its unclear what the code behind the scenes does.https://www.dcode.fr/choices-combinations
Is there someone who can provide me with the code to solve this solution or link me to an existing question which shows how.

Answer 1

You can use a recursive function to create all the combinations of each different subarray. For example:
function combinations($array) {
if (count($array) == 1) return reset($array);
$result = array();
foreach (reset($array) as $value) {
foreach (combinations(array_slice($array, 1)) as $comb) {
$result[] = array_merge($value, $comb);
}
}
return $result;
}
$input = '{"1":[["Red"],["Green"],["Blue"],["Purple"]],"2":[["S"],["M"],["L"]],"3":[["Wool"],["Cotton"]]}';
$arr = json_decode($input, true);
$combs = combinations($arr);
This will return an array of arrays like this (based on your sample input data):
Array
(
[0] => Array
(
[0] => Red
[1] => S
[2] => Wool
)
[1] => Array
(
[0] => Red
[1] => S
[2] => Cotton
)
[2] => Array
(
[0] => Red
[1] => M
[2] => Wool
)
...
[22] => Array
(
[0] => Purple
[1] => L
[2] => Wool
)
[23] => Array
(
[0] => Purple
[1] => L
[2] => Cotton
)
)
To get a list of comma separated strings, you can then use array_map to apply implode to those arrays e.g.
$csv = array_map(function ($a) { return implode(',', $a); }, $combs);
This will give an array like this:
Array
(
[0] => Red,S,Wool
[1] => Red,S,Cotton
[2] => Red,M,Wool
[3] => Red,M,Cotton
[4] => Red,L,Wool
[5] => Red,L,Cotton
[6] => Green,S,Wool
[7] => Green,S,Cotton
[8] => Green,M,Wool
[9] => Green,M,Cotton
[10] => Green,L,Wool
[11] => Green,L,Cotton
[12] => Blue,S,Wool
[13] => Blue,S,Cotton
[14] => Blue,M,Wool
[15] => Blue,M,Cotton
[16] => Blue,L,Wool
[17] => Blue,L,Cotton
[18] => Purple,S,Wool
[19] => Purple,S,Cotton
[20] => Purple,M,Wool
[21] => Purple,M,Cotton
[22] => Purple,L,Wool
[23] => Purple,L,Cotton
)
Demo on 3v4l.org

Answer 2

Your input is currently putting all of the colours inside of an array and then inside another array. [["Red"],["Green"],["Blue"],["Purple"]]. Ideally you want them to be like ["Red", "Green", "Blue", "Purple"].
Aside from that you can loop over the elements turn them into the desired structure.
Once you have the structure for the colours, sizes and materials then you can loop over them and add them to a new array.
$input = '{"1":[["Red"],["Green"],["Blue"],["Purple"]],"2":[["S"],["M"],["L"]],"3":[["Wool"],["Cotton"]]}';
$arr = json_decode($input, true);
$test = [];
$sizes = [];
$colours = [];
$materials = [];
foreach($arr[1] as $key => $colour) {
$colours[] = $colour[0];
}
foreach($arr[2] as $key => $size) {
$sizes[] = $size[0];
}
foreach($arr[3] as $key => $material) {
$materials[] = $material[0];
}
foreach ($colours as $key => $colour) {
foreach($sizes as $key => $size) {
foreach ($materials as $key => $material) {
$test[] = $colour .','. $size . ','. $material;
}
}
}
print_r($test);
While ideally this isn't the most efficient it will achieve your desired output.
Demo here