- array_map: documentation ( source)
- print_r: documentation ( source)
- implode: documentation ( source)
- array_keys: documentation ( source)
<?php
$input = array('item1' => 'object1', 'item2' => 'object2', 'item-n' => 'object-n');
$output = implode(', ', array_map(function ($v, $k) { return $k . '=' . $v; }, $input, array_keys($input)));
print_r($input, true);