Year and week to date in php

Question

I have two pieces of information extracted from a MySQL database, the year(2009, 2010, ect) and the week (1-52). And I need to convert it in to a date start and date end..

For example:

Year=2010, Week=1 would be (Friday, Jan 1st, 2010) - (Sunday, Jan 3rd, 2010)
Year=2010, Week=33 would be (Monday, Aug 16th, 2010) - (Sunday, Aug 22nd, 2010)
Year=2010, Week=34 would be (Monday, Aug 23rd, 2010) - (Sunday, Aug 29th, 2010)

How would I go about doing that in php ?

Answer 1

$year = "2010"; // Year 2010
$week = "01"; // Week 1

$date1 = date( "l, M jS, Y", strtotime($year."W".$week."1") ); // First day of week
$date2 = date( "l, M jS, Y", strtotime($year."W".$week."7") ); // Last day of week
echo $date1 . " - " . $date2;

If week number is under 10 then append a 0 before number. 1 won't work, it should be 01.

Answer 2

Since this question and the accepted answer were posted the DateTime classes make this much simpler to do:-

function daysInWeek($weekNum)
{
    $result = array();
    $datetime = new DateTime();
    $datetime->setISODate((int)$datetime->format('o'), $weekNum, 1);
    $interval = new DateInterval('P1D');
    $week = new DatePeriod($datetime, $interval, 6);

    foreach($week as $day){
        $result[] = $day->format('d/m/Y');
    }
    return $result;
}

var_dump(daysInWeek(24));

Output:-

array (size=7)
  0 => string '10/06/2013' (length=10)
  1 => string '11/06/2013' (length=10)
  2 => string '12/06/2013' (length=10)
  3 => string '13/06/2013' (length=10)
  4 => string '14/06/2013' (length=10)
  5 => string '15/06/2013' (length=10)
  6 => string '16/06/2013' (length=10)

This has the added advantage of taking care of leap years etc..