3v4l.org

run code in 300+ PHP versions simultaneously
<?php $s = ''; print "isset: '" . isset($s) . "'. "; print "!empty: '" . !empty($s) . "'"; ?>
Output for 5.5.0 - 5.5.38, 5.6.0 - 5.6.40, 7.0.0 - 7.0.33, 7.1.0 - 7.1.33, 7.2.0 - 7.2.34, 7.3.0 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.33, 8.2.0 - 8.2.29, 8.3.0 - 8.3.27, 8.4.1 - 8.4.14
isset: '1'. !empty: ''
preferences:
148.39 ms | 408 KiB | 5 Q