- implode: documentation ( source)
- explode: documentation ( source)
- array_filter: documentation ( source)
- trim: documentation ( source)
- array_pop: documentation ( source)
<?php
$str = 'item1|item2|item 3||item 4|||yyyy-mm-dd';
$array = explode('|', $str);
$array = array_filter($array);
$last = array_pop($array);
echo trim(implode (', ', $array)).' '.$last;