<?php
$input = "textmdwrhfejhg../,2222233333,34erw.re.ty";
//cut numbers after comma if there are any, after 2 digits
$matchPattern = '/[0-9]+(?:\,[0-9]{2}){0,2}/';
//remove everything except numbers, commas and dots
$repl1 = trim(preg_replace("/[^0-9,.]/", "", $input), ".,");
//let there be a 0 before comma to have values like 0,75, remove the 0
$repl2 = preg_replace("/^0/", "",$repl1);
//now i need you here to help me for the expression putting dots after each 3 numbers, until the comma:
$repl3 = preg_replace('/(\d)(?=(?:\d{3})+(?!\d))/', '$1.', $repl2);
echo "$repl3" . "\n";