- implode: documentation ( source)
- array_walk: documentation ( source)
<?php
$data = array(
'ordernumber' => '#ordernumber',
'transactionamount' => '#transactionamount',
);
array_walk($data,
create_function('&$value,$key', '$value = sprintf("%s|%s", $key, $value);')
);
echo implode('|', $data);