How to print a number from a string if there is a ">" sign in the string PHP?

Question

PHP

Good afternoon. There is the following code:

$str_test = ">100";
if (preg_match('/(>)?(\d+)/i', $str_test, $matches)) {
  print_r($matches[0]);
}

As a result, >100 is displayed, but I need to display only a number if there is a ">" sign in the string. How to do it?