Multiply two arrays with different length in PHP? - php

Question

I have a dynamic array:
$variants = [
'color' => ['Blue', 'Red', 'Pink'],
'size' => ['X', 'S'],
... (maybe more elements like above or not)
];
I expect this:
$result = [
0 => ['color' => 'Blue', 'size' => 'X'],
1 => ['color' => 'Blue', 'size' => 'S'],
2 => ['color' => 'Red', 'size' => 'X'],
3 => ['color' => 'Red', 'size' => 'S'],
4 => ['color' => 'Pink', 'size' => 'X'],
5 => ['color' => 'Pink', 'size' => 'S']
];
Result is the multiplying of all array lengths. I've searched but not found the solution yet. Hope anyone could help. Many thanks!

Answer 1

This is a bit tricky, you need a preparation and an aggregation step for this. But it is possible without falling back to recursion:
<?php
$variants = [
'color' => ['Blue', 'Red', 'Pink'],
'size' => ['X', 'S'],
'weight' => [150, 250]
];
$result = [];
foreach ($variants as $key => $set) {
foreach ($set as $entry) {
$result[] = [$key => $entry];
}
break;
}
array_shift($variants);
foreach($variants as $setKey => $set) {
$buffer = $result;
$result = [];
foreach ($set as $entry) {
foreach ($buffer as $buf) {
$result[] = array_merge($buf, [$setKey => $entry]);
}
}
}
var_dump($result);
The output of that is:
array(12) {
[0]=>
array(3) {
["color"]=>
string(4) "Blue"
["size"]=>
string(1) "X"
["weight"]=>
int(150)
}
[1]=>
array(3) {
["color"]=>
string(3) "Red"
["size"]=>
string(1) "X"
["weight"]=>
int(150)
}
[2]=>
array(3) {
["color"]=>
string(4) "Pink"
["size"]=>
string(1) "X"
["weight"]=>
int(150)
}
[3]=>
array(3) {
["color"]=>
string(4) "Blue"
["size"]=>
string(1) "S"
["weight"]=>
int(150)
}
[4]=>
array(3) {
["color"]=>
string(3) "Red"
["size"]=>
string(1) "S"
["weight"]=>
int(150)
}
[5]=>
array(3) {
["color"]=>
string(4) "Pink"
["size"]=>
string(1) "S"
["weight"]=>
int(150)
}
[6]=>
array(3) {
["color"]=>
string(4) "Blue"
["size"]=>
string(1) "X"
["weight"]=>
int(250)
}
[7]=>
array(3) {
["color"]=>
string(3) "Red"
["size"]=>
string(1) "X"
["weight"]=>
int(250)
}
[8]=>
array(3) {
["color"]=>
string(4) "Pink"
["size"]=>
string(1) "X"
["weight"]=>
int(250)
}
[9]=>
array(3) {
["color"]=>
string(4) "Blue"
["size"]=>
string(1) "S"
["weight"]=>
int(250)
}
[10]=>
array(3) {
["color"]=>
string(3) "Red"
["size"]=>
string(1) "S"
["weight"]=>
int(250)
}
[11]=>
array(3) {
["color"]=>
string(4) "Pink"
["size"]=>
string(1) "S"
["weight"]=>
int(250)
}
}

Answer 2

A function that makes what you want
function get_combinations($arrays) {
$result = array(array());
foreach ($arrays as $property => $property_values) {
$tmp = array();
foreach ($result as $result_item) {
foreach ($property_values as $property_value) {
$tmp[] = array_merge($result_item, array($property => $property_value));
}
}
$result = $tmp;
}
return $result;
}
$variants = [
'color' => ['Blue', 'Red', 'Pink'],
'size' => ['X', 'S']
];
$result = get_combinations($variants);
The result will be like you want it.