月の何週目か取得

gistfile1.php

<?php
/**
 * 月の何週目か取得
 * @param integer $y 年
 * @param integer $m 月
 * @param integer $d 日
 */
function getNthWeek($y, $m, $d)
{
    $week1 = date('W', mktime(0, 0, 0, $m, 1, $y));
    $week2 = date('W', mktime(0, 0, 0, $m, $d, $y));

    $week_num = $week2 - $week1 + 1;

    return $week_num;

}