3v4l.org

run code in 150+ php & hhvm versions
Bugs & Features
<?php echo "regex!"; echo preg_replace('/(\d+)-?(\d)/', '${1} ${1}', "16656400-k");
Output for 4.3.0 - 5.6.28, hhvm-3.10.0 - 3.12.0, 7.0.0 - 7.1.0
regex!1665640 1665640-k