3v4l.org

run code in 300+ PHP versions simultaneously
<?php $array = [1,2,3,2,4,1,1,2,3]; while ($arr= current($array)) { if ($arr == '2') { echo "key=".key($array).'<br />'; } next($array); }
Output for 5.5.0 - 5.5.37, 5.6.0 - 5.6.23, 7.0.0 - 7.0.20, 7.1.0 - 7.1.20, 7.2.6 - 7.2.33, 7.3.16 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.28, 8.2.0 - 8.2.18, 8.3.0 - 8.3.4, 8.3.6
key=1<br />key=3<br />key=7<br />
Output for 8.3.5
Warning: PHP Startup: Unable to load dynamic library 'sodium.so' (tried: /usr/lib/php/8.3.5/modules/sodium.so (libsodium.so.23: cannot open shared object file: No such file or directory), /usr/lib/php/8.3.5/modules/sodium.so.so (/usr/lib/php/8.3.5/modules/sodium.so.so: cannot open shared object file: No such file or directory)) in Unknown on line 0 key=1<br />key=3<br />key=7<br />
preferences:
220.08 ms | 402 KiB | 216 Q