如何从日期，星期和年份获取具体日期

I want get specific date based on days, number of week and years,

$days = "Monday";
$number_of_week = date('W'); // 1 to 42 total number of weeks in years
$year = date('Y'); // 2017

getSpecificDate($days, $number_of_week, $year);

it will return

2017-02-20

How to get that?

Try this:

$days = "Tuesday";
$number_of_week = date('W'); // 1 to 42 total number of weeks in years
$year = date('Y'); // 2017

function getSpecificDate($days, $number_of_week, $year){
   $week_day = date( "Y-m-d", strtotime($year."W".$number_of_week) );

   $date_time = strtotime($week_day.' next '.$days);

   return date('Y-m-d', $date_time);
}

echo getSpecificDate($days, $number_of_week, $year);

The function like this:

$year : year

$week : if 1~9, should prepended 0, like 01~09

$days : 1~7

getSpecificDate($days, $week, $year) {

    return date("Y-m-d", strtotime($year . "W" . sprintf("%02u", $week) . $days)); 

}