3v4l.org

run code in 300+ PHP versions simultaneously
<?php $a = ""; $a[] = "y"; var_dump($a); $b = "x"; $b[] = "y"; var_dump($b);
Output for 7.1.0 - 7.1.25, 7.2.0 - 7.2.33, 7.3.0 - 7.3.33, 7.4.0 - 7.4.27, 8.0.0 - 8.0.15, 8.1.0 - 8.1.2
Fatal error: Uncaught Error: [] operator not supported for strings in /in/vg7Oe:2 Stack trace: #0 {main} thrown in /in/vg7Oe on line 2
Process exited with code 255.
Output for 7.0.0 - 7.0.20
array(1) { [0]=> string(1) "y" } Fatal error: Uncaught Error: [] operator not supported for strings in /in/vg7Oe:3 Stack trace: #0 {main} thrown in /in/vg7Oe on line 3
Process exited with code 255.
Output for 4.3.2 - 4.3.11, 4.4.0 - 4.4.9, 5.0.0 - 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, 5.5.0 - 5.5.38, 5.6.0 - 5.6.28
array(1) { [0]=> string(1) "y" } Fatal error: [] operator not supported for strings in /in/vg7Oe on line 3
Process exited with code 255.
Output for 4.3.0 - 4.3.1
array(1) { [0]=> string(1) "y" } Fatal error: [] operator not supported for strings in /in/vg7Oe on line 3

preferences:
54.75 ms | 462 KiB | 5 Q