- implode: documentation ( source)
- explode: documentation ( source)
- trim: documentation ( source)
- array_pop: documentation ( source)
<?php
$str = 'item1|item2|item 3|yyyy-mm-dd';
$array = explode('|', $str);
$last = array_pop($array);
echo trim(implode (', ', $array)).' '.$last;