3v4l.org

run code in 300+ PHP versions simultaneously
<?php if (empty($mystring)) { echo "empty\n"; } if ($mystring == null) { echo "null\n"; // Undefined variable } if (!isset($mystring)) { echo "unset\n"; }
Output for 8.0.0 - 8.0.30, 8.1.0 - 8.1.28, 8.2.0 - 8.2.18, 8.3.0 - 8.3.6
empty Warning: Undefined variable $mystring in /in/DmaOr on line 5 null unset
Output for 5.0.4 - 5.0.5, 5.1.0 - 5.1.6, 5.2.0 - 5.2.17, 5.3.0 - 5.3.29, 5.4.0 - 5.4.45, 5.5.24 - 5.5.35, 5.6.8 - 5.6.28, 7.0.0 - 7.0.20, 7.1.0 - 7.1.33, 7.2.0 - 7.2.33, 7.3.0 - 7.3.31, 7.4.0 - 7.4.33
empty Notice: Undefined variable: mystring in /in/DmaOr on line 5 null unset
Output for 7.3.32 - 7.3.33
empty null unset
Output for 4.3.0 - 4.3.11, 4.4.0 - 4.4.9, 5.0.0 - 5.0.3
empty Notice: Undefined variable: mystring in /in/DmaOr on line 5 null unset
preferences:
221.34 ms | 402 KiB | 342 Q