Online PHP editor | output for khjJh

<?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(), $key = '', $value = ''){ $return = array(); $current = array_shift($source_arrays); foreach($current as $ck => $cv) { $ckey = $key.$ck; $cvalue = $value.$cv; if(!empty($source_arrays)) { $return += getAllCombinationsArray($source_arrays, $ckey.'_', $cvalue.' -> '); } else { $return[$ckey] = $cvalue; } return $return; } print_r(getAllCombinationsArray(array($root, $child_1, $child_2)));