3v4l.org

run code in 300+ PHP versions simultaneously
<?php $str="2011"; $week="01"; echo date("Y-m-d", strtotime($str."W".$week)); ?>
Output for 5.1.0 - 5.1.6, 5.2.0 - 5.2.17, 5.3.0 - 5.3.29, 5.4.0 - 5.4.45, 5.5.0 - 5.5.38, 5.6.0 - 5.6.28, 7.0.0 - 7.0.20, 7.1.0 - 7.1.10, 7.2.0 - 7.2.33, 7.3.12 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.28, 8.2.0 - 8.2.18, 8.3.0 - 8.3.6
2011-01-03
Output for 5.0.0 - 5.0.5
2010-12-20
Output for 4.3.0 - 4.3.11, 4.4.0 - 4.4.9
1970-01-01
preferences:
250.7 ms | 401 KiB | 352 Q