3v4l.org

run code in 300+ PHP versions simultaneously
<?php $a = ['net' => ['domain' => ['www' => null, 'shit' => null]]]; function walk(array $a, $stem = '') { $result = []; foreach ($a as $k => $v) { $current = $stem ? "$stem.$k" : $k; if (is_array($v)) { $result = array_merge($result, walk($v, $current)); } else { $result[] = $current; } } return $result; } foreach (walk($a) as $domain) { print "$domain\n"; }
Output for 5.5.0 - 5.5.35, 5.6.0 - 5.6.28, 7.0.0 - 7.0.20, 7.1.0 - 7.1.20, 7.2.0 - 7.2.33, 7.3.16 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.34, 8.2.0 - 8.2.30, 8.3.0 - 8.3.30, 8.4.1 - 8.4.18, 8.5.0 - 8.5.3
net.domain.www net.domain.shit

preferences:
96.01 ms | 1617 KiB | 4 Q