- preg_match: documentation ( source)
<?php
$a = "some_text_v1_I1_some_mote__text";
$b = 2;
$c = $b - 1;
$d = $b + 1;
$c = "/(i(ssue)?(" . $b . "\d)|(\d" . $b . "))|(i(ssue)?[0-" . ($b - 1) . ($b + 1) . "-9])|(faculty)|(Internal)|(Final)/i";
if (!preg_match($c, $a)) {
echo 1;
} else {
echo 2;
}