3v4l.org

run code in 300+ PHP versions simultaneously
<?php $symbolstocheck = [1, 1, 3, 1, 5]; $prev = null; $keyz = -1; $res = []; foreach ($symbolstocheck as $value) { $value = (int)$value; if ($value !== $prev) { $keyz++; } $prev = $value; if (!isset($res[$keyz])) { $res[$keyz] = ''; } $res[$keyz] .= $value; } var_dump($res);
Output for 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, 8.0.0 - 8.0.30, 8.1.0 - 8.1.33, 8.2.0 - 8.2.29, 8.3.0 - 8.3.25, 8.4.1 - 8.4.12
array(4) { [0]=> string(2) "11" [1]=> string(1) "3" [2]=> string(1) "1" [3]=> string(1) "5" }
preferences:
124.78 ms | 408 KiB | 5 Q