- var_dump: documentation ( source)
- array_filter: documentation ( source)
- array_is_list: documentation ( source)
<?php
$a = [1, 2, 3, 4, 5];
$b = array_filter($a, fn ($x) => $x <= 3);
$c = array_filter($a, fn ($x) => $x >= 3);
var_dump(array_is_list($a));
var_dump(array_is_list($b));
var_dump(array_is_list($c));