3v4l.org

run code in 300+ PHP versions simultaneously
<?php $foo = 'foo'; $foo[0] = 42; var_dump($foo);
Output for 8.0.0 - 8.0.30, 8.1.0 - 8.1.27, 8.2.0 - 8.2.17, 8.3.0 - 8.3.4
Warning: Only the first byte will be assigned to the string offset in /in/QhiEf on line 4 string(3) "4oo"
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 - 7.2.33, 7.3.0 - 7.3.33, 7.4.0 - 7.4.33
string(3) "4oo"

preferences:
174.87 ms | 403 KiB | 326 Q