A response to http://pastie.org/pastes/6350474/text

gistfile1.php

<?php

$array_1 = array( 'apple', 'orange', 'bananna', 'grape' );

$array_2 = array(
    'apple' => 'pear',
    'grape' => 'pineapple',
);

$result = array();
foreach ( $array_1 as $test ) {
	if ( isset ( $array_2[$test] ) )
		$result[] = $array_2[$test];
	else
		$result[] = $test;
}

print_r($result);