/**
* Compute the Cartesian product of multiple associative arrays.
*
* Example:
* [
* ["color" => "red", "color" => "blue"],
* ["size" => "S", "size" => "M"],
* ]
*
* Result:
* [
* ["color" => "red", "size" => "S"],
* ["color" => "red", "size" => "M"],
* ["color" => "blue", "size" => "S"],
* ["color" => "blue", "size" => "M"]
* ]
*/
/**
* cartesianProduct()
* -------------------
* Takes an array of associative arrays and returns the Cartesian product.
*/
function cartesianProduct(array $arrays)
{
// Start with one empty combination
$result = [[]];
// Loop through each associative array
foreach ($arrays as $assocArray) {
// Temporary array to store new combinations
$newResult = [];
// Loop through existing combinations
foreach ($result as $partialCombination) {
// Loop through each key/value pair in the current associative array
foreach ($assocArray as $key => $value) {
// Create a new combination by adding this key/value pair
$newCombination = $partialCombination;
$newCombination[$key] = $value;
// Store the new combination
$newResult[] = $newCombination;
}
}
// Replace the old result with the expanded one
$result = $newResult;
}
return $result;
}
// ------------------------------------------------------------
// Example usage
// ------------------------------------------------------------
// First associative array
$colors = [
"color" => "red",
"color2" => "blue"
];
// Second associative array
$sizes = [
"size" => "S",
"size2" => "M"
];
// Third associative array
$materials = [
"material" => "cotton",
"material2" => "polyester"
];
// Put all arrays into one list
$inputArrays = [$colors, $sizes, $materials];
// Compute the Cartesian product
$product = cartesianProduct($inputArrays);
// Print the result
echo "Cartesian Product:\n";
foreach ($product as $combo) {
print_r($combo);
}
/*
run:
Cartesian Product:
Array
(
[color] => red
[size] => S
[material] => cotton
)
Array
(
[color] => red
[size] => S
[material2] => polyester
)
Array
(
[color] => red
[size2] => M
[material] => cotton
)
Array
(
[color] => red
[size2] => M
[material2] => polyester
)
Array
(
[color2] => blue
[size] => S
[material] => cotton
)
Array
(
[color2] => blue
[size] => S
[material2] => polyester
)
Array
(
[color2] => blue
[size2] => M
[material] => cotton
)
Array
(
[color2] => blue
[size2] => M
[material2] => polyester
)
*/
