You can add a prefix or suffix to every element of an array succinctly using preg_filter().

<?php
$ids = range(1, 5);

$prefixedIds = preg_filter('/^/', 'prefix_', $ids);
$suffixedIds = preg_filter('/$/', '_suffix', $ids);

print_r($prefixedIds);
print_r($suffixedIds);

The print statements above will output:

Array
(
    [0] => prefix_1
    [1] => prefix_2
    [2] => prefix_3
    [3] => prefix_4
    [4] => prefix_5
)

Array
(
    [0] => 1_suffix
    [1] => 2_suffix
    [2] => 3_suffix
    [3] => 4_suffix
    [4] => 5_suffix
)

Simple and clean solution for prefixing or appending to every element in an array.

Credit goes to Dávid Horváth and his answer on StackOverflow.