First off, from the PHP.net Manual, the ‘W’ inside the date() function returns the week number for a year.
Week
ISO-8601 week number of year, weeks starting on Monday (added in PHP 4.1.0)
Example: 42 (the 42nd week in the year)
A quick example of date(‘W’)
<?php //October 29, 2009 is my birthday echo date('W', strtotime('2009-10-29')); //OUTPUT: 44 //October 29 is the 44th week in the year 2009 |
Here is the function to get the start and end dates given a week number:
function getWeekDates($year, $week, $start=true) { $from = date("Y-m-d", strtotime("{$year}-W{$week}-1")); //Returns the date of monday in week $to = date("Y-m-d", strtotime("{$year}-W{$week}-7")); //Returns the date of sunday in week if($start) { return $from; } else { return $to; } //return "Week {$week} in {$year} is from {$from} to {$to}."; } |
I did a couple of tests and so far the code worked okay. If you have a better way of doing it, post it below 
PS: I got some of the code from a PHP.net comment and could no longer find the source. If you know the source, contact me.
twitter.com/wenbert
it’s very useful for me
thanks to every all
Thanks ekini.net for providing me the code. It’s helped me to use for my project. Once again, thank you very much.
if $week < 10, then
$from = 1970-01-01
and
$to = 1970-01-01
The problem with weeks 1-9 is they are only 1 digit in length. Pad them with a leading zero and you’ll have more luck.
When finding the solution to that problem I found the following page which suggests a simpler format for the strtotime command:
http://derickrethans.nl/calculating-start-and-end-dates-of-a-week.html:
For week 37 of year 2006
Monday: strtotime("2006W37")
Sunday: strtotime("2006W377")
I tested the following and works fine:
Monday: strtotime("2012W52")
Sunday: strtotime("2012W527")
Monday: strtotime("2013W01")
Sunday: strtotime("2013W017")
My code is:
Monday: strtotime($year.'W'.str_pad($week, 2, 0, STR_PAD_LEFT))
Sunday: strtotime($year.'W'.str_pad($week, 2, 0, STR_PAD_LEFT).'7')
HTH, Paul.