- array_map: documentation ( source)
- var_dump: documentation ( source)
- implode: documentation ( source)
- array_keys: documentation ( source)
- sprintf: documentation ( source)
<?php
$e = ['s' => 3, 'd' => 4];
var_dump(implode(', ', array_map(
function ($v, $k) { return sprintf("%s='%s'", $k, $v); },
$e,
array_keys($e)
)));