- array_intersect_key: documentation ( source)
- print_r: documentation ( source)
- array_values: documentation ( source)
- array_flip: documentation ( source)
- explode: documentation ( source)
<?php
$str = "5,1";
$base = array('1'=>'Bread','5'=>'Butter');
$flipped = array_flip( explode(',', $str));
print_r( $flipped);
$intersection = array_intersect_key( $base, $flipped);
print_r( $intersection);
$replacements = array_values( $intersection);
print_r( $replacements);