3v4l.org

run code in 150+ php & hhvm versions
Bugs & Features
<?php echo date('YW', strtotime('2013-12-30')); echo "<br />"; echo date('oW', strtotime('2013-12-30'));
Output for 5.1.0 - 5.6.28, hhvm-3.10.0 - 3.12.0, 7.0.0 - 7.1.0
201301<br />201401
Output for 4.4.1 - 4.4.9, 5.0.5
201301<br />o01
Output for 4.3.0 - 4.4.0, 5.0.0 - 5.0.4
20131<br />o1