For array_unshift() and array_push(), you include an array as one of the values to add, the array is added to the original array as an element.
It will turn the original array into a multidimensional array:
<?php $authors = array("A","B","C","D"); $newAuthors = array("Hardy","M"); echo array_push($authors, $newAuthors)."\n"; // Displays"5" print_r($authors);//from ww w .jav a 2 s . c o m ?>