日期函数，用于确定给定日期和日期的最近日期

Question

I need a function that gives me a date, given a date and a day. My week starts always on a Saturday and ends on a Friday. I need to know the date of each of the days of this week, given any date in this week.

getdatefromday($date,$day);

For example :

$date = "2016/04/10";
$day = "Thu";
getdatefromday($date,$day);
//Result is 2016-04-14 

I have solved this problem already using the code bellow, but I am sure this can be solved in lot less lines, I just can't figure it out.

This is my solution to this problem :

function getdatefromday($date,$day) {
    $curr_day = date("D", strtotime($date));
    switch ($curr_day) {
    case 'Sat':
        switch ($day) {
            case 'Sat':
                return $date;
                break;
            case 'Sun':
                return date('Y-m-d',(strtotime ( '+1 day' , strtotime ( $date) ) ));
                break;              
            case 'Mon':
                return date('Y-m-d',(strtotime ( '+2 day' , strtotime ( $date) ) ));
                break;
            case 'Tue':
                return date('Y-m-d',(strtotime ( '+3 day' , strtotime ( $date) ) ));
                break;
            case 'Wed':
                return date('Y-m-d',(strtotime ( '+4 day' , strtotime ( $date) ) ));
                break;
            case 'Thu':
                return date('Y-m-d',(strtotime ( '+5 day' , strtotime ( $date) ) ));
                break;
            case 'Fri':
                return date('Y-m-d',(strtotime ( '+6 day' , strtotime ( $date) ) ));
                break;                      
            }
    case 'Sun':
            switch ($day) {
            case 'Sat':
                return date('Y-m-d',(strtotime ( '-1 day' , strtotime ( $date) ) ));
                break;
            case 'Sun':
                return $date;
                break;              
            case 'Mon':
                return date('Y-m-d',(strtotime ( '+1 day' , strtotime ( $date) ) ));
                break;
            case 'Tue':
                return date('Y-m-d',(strtotime ( '+2 day' , strtotime ( $date) ) ));
                break;
            case 'Wed':
                return date('Y-m-d',(strtotime ( '+3 day' , strtotime ( $date) ) ));
                break;
            case 'Thu':
                return date('Y-m-d',(strtotime ( '+4 day' , strtotime ( $date) ) ));
                break;
            case 'Fri':
                return date('Y-m-d',(strtotime ( '+5 day' , strtotime ( $date) ) ));
                break;                      
            }
        break;
    case 'Mon':
        switch ($day) {
            case 'Sat':
                return date('Y-m-d',(strtotime ( '-2 day' , strtotime ( $date) ) ));
                break;
            case 'Sun':
                return date('Y-m-d',(strtotime ( '-1 day' , strtotime ( $date) ) ));
                break;              
            case 'Mon':
                return $date;
                break;
            case 'Tue':
                return date('Y-m-d',(strtotime ( '+1 day' , strtotime ( $date) ) ));
                break;
            case 'Wed':
                return date('Y-m-d',(strtotime ( '+2 day' , strtotime ( $date) ) ));
                break;
            case 'Thu':
                return date('Y-m-d',(strtotime ( '+3 day' , strtotime ( $date) ) ));
                break;
            case 'Fri':
                return date('Y-m-d',(strtotime ( '+4 day' , strtotime ( $date) ) ));
                break;                      
            }
    case 'Tue':
        switch ($day) {
            case 'Sat':
                return date('Y-m-d',(strtotime ( '-3 day' , strtotime ( $date) ) ));
                break;
            case 'Sun':
                return date('Y-m-d',(strtotime ( '-2 day' , strtotime ( $date) ) ));
                break;              
            case 'Mon':
                return date('Y-m-d',(strtotime ( '-1 day' , strtotime ( $date) ) ));
                break;
            case 'Tue':
                return $date;
                break;
            case 'Wed':
                return date('Y-m-d',(strtotime ( '+1 day' , strtotime ( $date) ) ));
                break;
            case 'Thu':
                return date('Y-m-d',(strtotime ( '+2 day' , strtotime ( $date) ) ));
                break;
            case 'Fri':
                return date('Y-m-d',(strtotime ( '+3 day' , strtotime ( $date) ) ));
                break;                      
            }       
    case 'Wed':
        switch ($day) {
            case 'Sat':
                return date('Y-m-d',(strtotime ( '-4 day' , strtotime ( $date) ) ));
                break;
            case 'Sun':
                return date('Y-m-d',(strtotime ( '-3 day' , strtotime ( $date) ) ));
                break;              
            case 'Mon':
                return date('Y-m-d',(strtotime ( '-2 day' , strtotime ( $date) ) ));
                break;
            case 'Tue':
                return date('Y-m-d',(strtotime ( '-1 day' , strtotime ( $date) ) ));
                break;
            case 'Wed':
                return $date;
                break;
            case 'Thu':
                return date('Y-m-d',(strtotime ( '+1 day' , strtotime ( $date) ) ));
                break;
            case 'Fri':
                return date('Y-m-d',(strtotime ( '+2 day' , strtotime ( $date) ) ));
                break;                      
            }
    case 'Thu':
        switch ($day) {
            case 'Sat':
                return date('Y-m-d',(strtotime ( '-5 day' , strtotime ( $date) ) ));
                break;
            case 'Sun':
                return date('Y-m-d',(strtotime ( '-4 day' , strtotime ( $date) ) ));
                break;              
            case 'Mon':
                return date('Y-m-d',(strtotime ( '-3 day' , strtotime ( $date) ) ));
                break;
            case 'Tue':
                return date('Y-m-d',(strtotime ( '-2 day' , strtotime ( $date) ) ));
                break;
            case 'Wed':
                return date('Y-m-d',(strtotime ( '-1 day' , strtotime ( $date) ) ));
                break;
            case 'Thu':
                return $date;
                break;
            case 'Fri':
                return date('Y-m-d',(strtotime ( '+1 day' , strtotime ( $date) ) ));
                break;                      
            }   
    case 'Fri':
        switch ($day) {
            case 'Sat':
                return date('Y-m-d',(strtotime ( '-6 day' , strtotime ( $date) ) ));
                break;
            case 'Sun':
                return date('Y-m-d',(strtotime ( '-5 day' , strtotime ( $date) ) ));
                break;              
            case 'Mon':
                return date('Y-m-d',(strtotime ( '-4 day' , strtotime ( $date) ) ));
                break;
            case 'Tue':
                return date('Y-m-d',(strtotime ( '-3 day' , strtotime ( $date) ) ));
                break;
            case 'Wed':
                return date('Y-m-d',(strtotime ( '-2 day' , strtotime ( $date) ) ));
                break;
            case 'Thu':
                return date('Y-m-d',(strtotime ( '-1 day' , strtotime ( $date) ) ));
                break;
            case 'Fri':
                return $date;
                break;                      
            }       
        }


}

Any ideas?

Answer 1

Try this function:

function getDateFromDay($date, $day) {
    $day = new DateTime($day);
    $day_w = $day->format('w');
    if ($day_w == 6) $day_w = -1;

    $date = new DateTime($date);
    $date_w = $date->format('w');
    if ($date_w == 6) $date_w = -1;

    $d = $day_w - $date_w;
    $date->modify("$d days");
    return $date->format('Y-m-d');
}

<kbd>demo</kbd>