Bug #63970 [Opn->Nab]: Wrong year on week calculation from 2012-12-30

Edit report at https://bugs.php.net/bug.php?id=63970&edit=1 ID: 63970 Updated by: derick@php.net Reported by: obibann at hotmail dot com Summary: Wrong year on week calculation from 2012-12-30 -Status: Open +Status: Not a bug Type: Bug Package: Date/time related Operating System: RedHat EL 6.2 PHP Version: 5.3.20 Block user comment: N Private report: N New Comment: Thank you for taking the time to write to us, but this is not a bug. Please double-check the documentation available at http://www.php.net/manual/ and the instructions on how to report a bug at http://bugs.php.net/how-to-report.php This is not a bug. "Y" is the real year, where as "o" is the ISO year. The "W" denotes the "ISO Week number" which ties in into the "ISO Year". Please refer to http://en.wikipedia.org/wiki/ISO_week for the back story. When you run your script with "o" instead of "Y", the answer is the correct "201152": <?php date_default_timezone_set("Europe/Paris"); echo date("o-W",strtotime("2012-12-30 11:00 -52 week")), "\n"; ?> Shows: 2011-52 Previous Comments: ------------------------------------------------------------------------ [2013-01-11 16:34:42] obibann at hotmail dot com Erratum : I think it should return "201152" ------------------------------------------------------------------------ [2013-01-11 16:31:28] obibann at hotmail dot com Description: ------------ Set your server on December 30 2012: date -s "20121230 11:00" Ask PHP to give you the year and week 52 weeks ago thanks to the code below. PHP prints "201252" instead of "201201" No problems from other dates of with another value of week. Test script: --------------- date_default_timezone_set("Your/Timezone"); // For me Europe/Paris echo date("YW",strtotime("-52 week")); Expected result: ---------------- 201201 Actual result: -------------- 201252 ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=63970&edit=1