- print_r: documentation ( source)
- array_fill_keys: documentation ( source)
<?php
$array1 = array(
"a" => "first",
"b" => "second",
"c" => "something", "red"
);
$array2 = array(
"a" => "first",
"b" => "something", "letsc"
);
print_r(array_fill_keys($array1, $array2));