- var_dump: documentation ( source)
- array_reduce: documentation ( source)
- max: documentation ( source)
<?php
$arrayMax = function ($max, $value) use (&$arrayMax) {
if (is_array($value)) return array_reduce($value, $arrayMax, $max);
elseif (is_int($value)) return $max === null ? $value : max($max, $value);
else return $max;
};
var_dump(array_reduce([5, 7, 2, ['25', [20]]], $arrayMax));