Get week number (in the year) from a date PHP

Question

I want to take a date and work out its week number.

So far, I have the following. It is returning 24 when it should be 42.

<?php $ddate = "2012-10-18"; $duedt = explode("-",$ddate); $date = mktime(0, 0, 0, $duedt[2], $duedt[1],$duedt[0]); $week = (int)date('W', $date); echo "Weeknummer: ".$week; ?> 

Is it wrong and a coincidence that the digits are reversed? Or am I nearly there?

Answer 1

Today, using PHP's DateTime objects is better:

<?php $ddate = "2012-10-18"; $date = new DateTime($ddate); $week = $date->format("W"); echo "Weeknummer: $week"; 

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It's because in mktime(), it goes like this:

mktime(hour, minute, second, month, day, year); 

Hence, your order is wrong.

<?php $ddate = "2012-10-18"; $duedt = explode("-", $ddate); $date  = mktime(0, 0, 0, $duedt[1], $duedt[2], $duedt[0]); $week  = (int)date('W', $date); echo "Weeknummer: " . $week; ?>