- var_dump: documentation ( source)
- preg_match: documentation ( source)
- preg_quote: documentation ( source)
- sprintf: documentation ( source)
<?php
$source = 'Test [1]';
$existing = 'Test';
$pattern = sprintf('/%s \[\d+\]/', preg_quote($source, '/'));
var_dump(preg_match($pattern, $existing));