Build array of dates from defined date object

week.php

$cols = array();
$date = new DateTime(date('Y-m-d', strtotime('-1 week')));

for ($i = 0; $i < 7; $i++) {

    $cols[$date->format('l')] = array(
        'label' => $date->format('Y-m-d')
    );

    $date->modify('+1 day');
}