Try Rector Online | Rector - Automated Way to Instantly Upgrade and Refactor any PHP code

Run Rector on your code to see what it can do for you:

 {
     public function run(string $param)
     {
-        return preg_match('/^[0-9]+$/', $param);
+        return preg_match('/^d+$/', $param);
     }
 }

PHP snippet to change

<?php

final class DemoFile
{
    public function run(string $param)
    {
        return preg_match('/^[0-9]+$/', $param);
    }
}

Applied Rules:

SimplifyRegexPatternRector

Not a change you expect?

Create an issue on GitHub
...or to speed up fix – add a test fixture

Config rector.php

<?php

use Rector\Config\RectorConfig;
use Rector\CodeQuality\Rector\FuncCall\SimplifyRegexPatternRector;
use Rector\ValueObject\PhpVersion;

return RectorConfig::configure()
    ->withRules([
        SimplifyRegexPatternRector::class
    ]);

Rector version: 16136f - released at 2026-03-16 17:05