Get all combinations from multiple nested arrays

Question

I am trying to find an algorithm in PHP to get all combinations for a nested array:

Array ( [0] => Array ( [0] => Option Object ( [strValue] => rough ) [1] => Option Object ( [strValue] => smooth ) [2] => Option Object ( [strValue] => coarse ) ) [1] => Array ( [0] => Option Object ( [strValue] => shiney ) [1] => Option Object ( [strValue] => mat ) ) [2] => Array ( [0] => Option Object ( [strValue] => Large ) [1] => Option Object ( [strValue] => Medium ) [2] => Option Object ( [strValue] => Small ) [3] => Option Object ( [strValue] => very large ) ) ) 

So, I would get something like:

- simple, shining, big

- transparent, small

-ru, shiney, Medium

- transparent, very large

- smooth, radiant, large

- smooth, shining, small

- smooth, shining, medium

- smooth, radiant, very large

etc. (in this example should be 24)

I tried various foreach examples and some basic recursive function, but it doesn't seem to get fast results. If anyone could give a basic plan on how to solve this, I would be very grateful, thanks!

Answer 1

I just wrote this, which works for arrays of any length.

 <?php function cartesian_product($a) { $result = array(array()); foreach ($a as $list) { $_tmp = array(); foreach ($result as $result_item) { foreach ($list as $list_item) { $_tmp[] = array_merge($result_item, array($list_item)); } } $result = $_tmp; } return $result; } // Let test this.. header('Content-type: text/plain'); $a = array( array('rough','smooth','coarse'), array('shiney','mat'), array('small','medium','large','x-large'), ); $result = cartesian_product($a); foreach ($result as $row) { print implode(", ", $row) ."\n"; } 

edit: slightly improved code.

Answer 2

Time for a nest of some foreach loops!

 <?php $array1 = array('rough', 'smooth', 'coarse'); $array2 = array('shiny', 'matte'); $array3 = array('very large', 'large', 'medium', 'small'); foreach($array1 as $i) foreach($array2 as $j) foreach($array3 as $k) $output[] = "$i, $j, $k"; var_dump($output); /* ouput array 0 => string 'rough, shiny, very large' (length=24) 1 => string 'rough, shiny, large' (length=19) 2 => string 'rough, shiny, medium' (length=20) 3 => string 'rough, shiny, small' (length=19) 4 => string 'rough, matte, very large' (length=24) 5 => string 'rough, matte, large' (length=19) 6 => string 'rough, matte, medium' (length=20) 7 => string 'rough, matte, small' (length=19) 8 => string 'smooth, shiny, very large' (length=25) 9 => string 'smooth, shiny, large' (length=20) 10 => string 'smooth, shiny, medium' (length=21) 11 => string 'smooth, shiny, small' (length=20) 12 => string 'smooth, matte, very large' (length=25) 13 => string 'smooth, matte, large' (length=20) 14 => string 'smooth, matte, medium' (length=21) 15 => string 'smooth, matte, small' (length=20) 16 => string 'coarse, shiny, very large' (length=25) 17 => string 'coarse, shiny, large' (length=20) 18 => string 'coarse, shiny, medium' (length=21) 19 => string 'coarse, shiny, small' (length=20) 20 => string 'coarse, matte, very large' (length=25) 21 => string 'coarse, matte, large' (length=20) 22 => string 'coarse, matte, medium' (length=21) 23 => string 'coarse, matte, small' (length=20) */ ?> 

Answer 3

Here is the brute force (worse performance) algorithm in psuedo-php:

 $array1 = $array[0]; $array2 = $array[1]; $array3 = $array[2]; $results = array(); for( $i = 0; $i < count( $array1); $i++) for( $j = 0; $j < count( $array2); $j++) for( $k = 0; $k < count( $array3); $k++) $results[] = $array1[$i] . ',' . $array2[$j] . ',' . $array3[$k];