Month by week of the year?

Question

I\'m trying to get the number of the month of the year by the number of a week of the year and the year. So for example week 1 is in january and returns 1, week 6 is in february

Answer 1

Just wanted to add a note for the first answer, the week number should be 01-09 for Weeks 1 through 9 (it will always give month 1 if you don't add the leading zero)

date("m",strtotime("2011-W06-1"));

Answer 2

Something like this will do, this is also tested and works:

function getMonthByNumber($number,$year)
{
    return date("F",strtotime('+ '.$number.' weeks', mktime(0,0,0,1,1,$year,-1)));
}

echo getMonthByNumber(27,2011);

Hope this helps

Answer 3

Using PHP DateTime objects (which is the preferred way of dealing with dates see links below for more info) you can accomplish it this way:

$dateTime = new \DateTime();
$dateTime->setISODate($year,$week);
$month = $dateTime->format('n');

Note that the following will not work as week "W" is not a supported format:

$month = \DateTime::createFromFormat("W/Y ", "1/2015")->format('n');

The format used by this method is the same supported by the function you where trying to use date_parse_from_format, hence the errors.

• Why PHP DateTime Rocks
• DateTime class vs. native PHP date-functions
• strtotime notes
• PHP/Architect's Guide to Date and Time Programming (Chapter 2)

Answer 4

print date("m",strtotime("2011-W6-1"));

(noting that in 2011, January has six weeks so week 6 (by some definitions) is in month 1).