FilterIterator::__construct

Usage example:

<?php

class AdultFilter extends \FilterIterator
{
    public function accept()
    {
        $person = $this->current();
        if (18 <= $person[1]) {
            return true;
        }
        return false;
    }
}

$persons = new \ArrayIterator([
    ['John', 27],
    ['Jack', 15],
    ['Jeff', 54],
]);

$adults = new AdultFilter($persons);

foreach ($adults as $adult) {
    var_dump($adult);
}