<?php
use Laminas\Filter;
$value = ',,--string,,..,';
$filterChain = new Filter\FilterChain();
// attach different filters and their priority
$filterChain->attach(new Filter\StringToUpper());
$filterChain->attach(new Filter\StringTrim(',.'), 1);
// because of priority, this filter has no "-" char to trim
$filterChain->attach(new Filter\StringTrim('-'), 2);
echo $filterChain->filter($value);