I refactored the Daniel's function and I got it:<?php/** * array_merge_recursive does indeed merge arrays, but it converts values with duplicate * keys to arrays rather than overwriting the value in the first array with the duplicate * value in the second array, as array_merge does. I.e., with array_merge_recursive, * this happens (documented behavior): * * array_merge_recursive(array('key' => 'org value'), array('key' => 'new value')); * => array('key' => array('org value', 'new value')); * * array_merge_recursive_distinct does not change the datatypes of the values in the arrays. * Matching keys' values in the second array overwrite those in the first array, as is the * case with array_merge, i.e.: * * array_merge_recursive_distinct(array('key' => 'org value'), array('key' => 'new value')); * => array('key' => array('new value')); * * Parameters are passed by reference, though only for performance reasons. They're not * altered by this function. * * @param array $array1 * @param array $array2 * @return array * @author Daniel <daniel (at) danielsmedegaardbuus (dot) dk> * @author Gabriel Sobrinho <gabriel (dot) sobrinho (at) gmail (dot) com> */function array_merge_recursive_distinct ( array &$array1, array &$array2 ){ $merged = $array1; foreach ( $array2 as $key => &$value ) { if ( is_array ( $value ) && isset ( $merged [$key] ) && is_array ( $merged [$key] ) ) { $merged [$key] = array_merge_recursive_distinct ( $merged [$key], $value ); } else { $merged [$key] = $value; } } return $merged;}?>This fix the E_NOTICE when the the first array doesn't have the key and the second array have a value which is a array.