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run code in 150+ php & hhvm versions
Bugs & Features
<?php $root = array( 1=>'cat1', 2=>'cat2', 3=>'cat3' ); $child_1 = array( 1=>'sub_cat1', 2=>'sub_cat2', 3=>'sub_cat3' ); $child_2 = array( 1=>'sub_sub_cat1', 2=>'sub_sub_cat2', 3=>'sub_sub_cat3' ); function getAllCombinationsArray($source_arrays = array(), $kd = array(), $vd = array()){ $return = array(); foreach(array_shift($source_arrays) as $ck => $cv) { $kdi = $kd + (array)$ck; $vdi = $vd + (array)$cv; if(!empty($source_arrays)) { $return += getAllCombinationsArray($source_arrays, $kdi, $vdi); } else { $return[implode('_', $kdi)] = implode(' -> ', $vdi); } } return $return; } print_r(getAllCombinationsArray(array($root, $child_1, $child_2)));
based on p5lVo
Output for 4.3.0 - 5.6.28, hhvm-3.10.0 - 3.12.0, 7.0.0 - 7.1.0
Array ( [1] => cat1 [2] => cat2 [3] => cat3 )