- is_numeric: documentation ( source)
- preg_match: documentation ( source)
- print_r: documentation ( source)
- str_replace: documentation ( source)
<?php
$text = "matrixrate_matrixrate_4";
$clean = str_replace('matrixrate_matrixrate_','',$text);
echo is_numeric($clean);
$rate = 'matrixrate_matrixrate_2';
preg_match("/^(matrixrate_matrixrate_)([0-9]*)/", $rate, $matches);
print_r($matches);