how to filter something out of an array

I thought so to but

$i = 0;
  foreach ( $files as $key => $file ) {
    if ( preg_match( $user_id, $file ) ) {
      $i++;
    }
  }
  echo '<p>'.$i.'</p>';

does not give anything.

hmm, am I that stupid

Array
(
    [0] => user_id_2_fbconfig.png
    [1] => userid_20_userid_2_ - kopie.png
    [2] => userid_2_fbconfig.png
)

$user_id = '/^userid_'.$pun_user['id'].'_(.*?)/';

$i = 0;
  foreach ( $files as $key => $file ) {
    if ( preg_match( $user_id, $file ) ) {
      $i++;
    }
  }
  echo '<p>'.$i.'</p>';

Now it shows just 1 if $user_id = 2

I do not know why it did not work the first time
Can I now also safely say that only the first userid_2_ is counted, this because when someone uploads a file that is called userid_50_userid_2_.png
that not the second userid_2_ is getting counted?
the first userid is added by the script to determine who uploaded the file.

That first question mark is a bit out of place, is it not? One assumes he would implicitly expect the underscore to be there.

yes that was my mistake, I did not copy that wright
It should be all userid_$id_

but it works now