3v4l.org

run code in 300+ PHP versions simultaneously
<?php var_dump(isset('foo')); var_dump(isset('')); var_dump(isset(null)); var_dump(isset(0)); var_dump(isset(1)); var_dump(isset([])); var_dump(isset([1]));
Output for 7.0.0 - 7.0.20, 7.1.0 - 7.1.7
Fatal error: Cannot use isset() on the result of an expression (you can use "null !== expression" instead) in /in/qVuvZ on line 3
Process exited with code 255.
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173.95 ms | 1395 KiB | 36 Q