PHP获取一年中的每星期的开始日期和结束日期

function get_week($year) { 

    $year_start = $year . "-01-01"; 

    $year_end = $year . "-12-31"; 

    $startday = strtotime($year_start); 

    if (intval(date('N', $startday)) != '1') { 

        $startday = strtotime("next monday", strtotime($year_start)); //获取年第一周的日期 

    } 

    $year_mondy = date("Y-m-d", $startday); //获取年第一周的日期 



    $endday = strtotime($year_end); 

    if (intval(date('W', $endday)) == '7') { 

        $endday = strtotime("last sunday", strtotime($year_end)); 

    } 



    $num = intval(date('W', $endday)); 

    for ($i = 1; $i <= $num; $i++) { 

        $j = $i -1; 

        $start_date = date("Y-m-d", strtotime("$year_mondy $j week ")); 



        $end_day = date("Y-m-d", strtotime("$start_date +6 day")); 



        $week_array[$i] = array ( 

            str_replace("-", 

            ".", 

            $start_date 

        ), str_replace("-", ".", $end_day)); 

    } 

    return $week_array; 

} 

$weeks = get_week(2011); 

echo '第18周开始日期：'.$weeks[18][0].''; 

echo '第18周结束日期：'.$weeks[18][1];