3v4l.org

run code in 300+ PHP versions simultaneously
<?php $str = 'Hello_world!'; $chars = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789/-'; $max = strlen($chars) - 1; echo preg_replace_callback( '/.\K/', fn() => $chars[rand(0, $max)], $str );

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23.45 ms | 405 KiB | 5 Q