- substr: documentation ( source)
- strrchr: documentation ( source)
<?php
//echo number_format(round(43.2550, 2), strlen(substr(strrchr("3.2550", "."), 1)), ',', '.');
echo strlen(substr(strrchr(3.2550, "."), 1));
echo PHP_EOL;
//echo number_format(round(553.4000, 2), strlen(substr(strrchr("3.4000", "."), 1)), ',', '.');
echo strlen(substr(strrchr(3.4000, "."), 1));