Cuantos lunes tiene un año

[marlanga]

Código PHP:

<?php
function dayInYear($year) {
    $names = ['domingo', 'lunes', 'martes', 'miercoles', 'jueves', 'viernes', 'sabado'];
    $days = array_fill(0, 7, 52);
    $fistDayInYear = new DateTime("{$year}-01-01");
    $days[$fistDayInYear->format('w')] += 1;
    $days[($fistDayInYear->format('w') + 1) % 7] += $fistDayInYear->format('L');
 
    return array_combine($names, $days);
}
 
$days = dayInYear(2017);
var_dump($days);