Getting first / last date of the week - php

Question

Is it possible to get the first / last date of a week using PHP's Relative Date Time format?
I've tried to do:
date_default_timezone_set('Europe/Amsterdam');
$date = new DateTime();
$date->modify('first day of this week'); // to get the current week's first date
echo $date->format('Y-m-d'); // outputs 2011-12-19
$date->modify('first day of week 50'); // to get the first date of any week by weeknumber
echo $date->format('Y-m-d'); // outputs 2011-12-18
$date->modify('last day of this week'); // to get the current week's last date
echo $date->format('Y-m-d'); // outputs 2011-12-17
$date->modify('last day of week 50'); // to get the last date of any week by weeknumber
echo $date->format('Y-m-d'); // outputs 2011-12-18
As you can see it doesn't output the correct dates.
According to the docs this should be possible if I'm correct.
Am I doing something terrible wrong?
EDIT
I need to use PHP's DateTime for dates in the far future.
UPDATE
It gets only stranger now. I've done some more testing.
Windows PHP 5.3.3
2011-12-01
Warning: DateTime::modify() [datetime.modify]: Failed to parse time string (first day of week 50) at position 13 (w): The timezone could not be found in the database in C:\Users\Gerrie\Desktop\ph\Websites\Charts\www.charts.com\public\index.php on line 9
2011-12-01
2011-11-30
Warning: DateTime::modify() [datetime.modify]: Failed to parse time string (last day of week 50) at position 12 (w): The timezone could not be found in the database in C:\Users\Gerrie\Desktop\ph\Websites\Charts\www.charts.com\public\index.php on line 15
2011-11-30
Linux 5.3.8
2011-12-01
2011-12-01
2011-11-30
2011-11-30

Answer 1

I'm a big fan of using the Carbon library, which makes this sort of thing really easy. For example:
use Carbon\Carbon;
$monday = Carbon::now()->startOfWeek()
$sunday = Carbon::now()->endOfWeek()
Or, if you'd prefer to have Sunday be the first day of your week:
use Carbon\Carbon;
Carbon::setWeekStartsAt(Carbon::SUNDAY);
Carbon::setWeekEndsAt(Carbon::SATURDAY);
$sunday = Carbon::now()->startOfWeek()
$saturday = Carbon::now()->endOfWeek()

Answer 2

According to docs the format strings "first day of" and "last day of" are only allowed for months, not for weeks. See http://www.php.net/manual/en/datetime.formats.relative.php
If you combine first and last day of with a week statement the result either blows the parser or is something that you did not expect (usually the first or last day of a month, not a week).
The difference that you see between Win and Linux is probably only because of different error reporting settings.
To get the first and last day of the current week use:
$date->modify('this week');
$date->modify('this week +6 days');
To get the first and last day of week 50 use:
$date->setISODate(2011, 50);
$date->setISODate(2011, 50, 7);
EDIT:
If you want to use the modify method for absolute week numbers you have to use the formats defined in http://www.php.net/manual/en/datetime.formats.compound.php:
$date->modify('2011W50');
$date->modify('2011W50 +6 days');

Answer 3

if first day of week is Monday
$date->modify('Monday this week');
else if first day is Sunday
$date->modify('Sunday this week');
because in different countries first day of week maybe Monday or Sunday

Answer 4

This is what I am using to get the first and last day of the week from any date.
In this case, monday is the first day of the week...
$date = date('Y-m-d'); // you can put any date you want
$nbDay = date('N', strtotime($date));
$monday = new DateTime($date);
$sunday = new DateTime($date);
$monday->modify('-'.($nbDay-1).' days');
$sunday->modify('+'.(7-$nbDay).' days');

Answer 5

function getweek_first_last_date($date)
{
$cur_date = strtotime($date); // Change to whatever date you need
// Get the day of the week: Sunday = 0 to Saturday = 6
$dotw = date('w', $cur_date);
if($dotw>1)
{
$pre_monday = $cur_date-(($dotw-1)*24*60*60);
$next_sunday = $cur_date+((7-$dotw)*24*60*60);
}
else if($dotw==1)
{
$pre_monday = $cur_date;
$next_sunday = $cur_date+((7-$dotw)*24*60*60);
}
else if($dotw==0)
{
$pre_monday =$cur_date -(6*24*60*60);;
$next_sunday = $cur_date;
}
$date_array = array();
$date_array['start_date_of_week'] = $pre_monday;
$date_array['end_date_of_week'] = $next_sunday;
return $date_array;
}
$date = '2013-12-22';
getweek_first_last_date($date);
Output :
$array_of_week = Array
(
[start_date_of_week] => 1387152000
[end_date_of_week] => 1387670400
)
$start_date =date('d/m/Y', $array_of_week['start_date_of_week'])

Answer 6

<code>
function getlastweek_first_last_date()
{
$cur_date = strtotime(date('Y-m-d')); // Change to whatever date you need
// Get the day of the week: Sunday = 0 to Saturday = 6
$previousweekcurdate = $cur_date - (7*24*3600);
$cur_date = $previousweekcurdate;
$dotw = date('w', $cur_date);
if($dotw>1)
{
$pre_sunday = $cur_date-(($dotw-1)*24*60*60) - (24*60*60);
$next_satday = $cur_date+((7-$dotw)*24*60*60)- (24*60*60);
}
else if($dotw==1)
{
$pre_sunday = $cur_date- (24*60*60);
$next_satday = $cur_date+((7-$dotw)*24*60*60)- (24*60*60);
}
else if($dotw==0)
{
$pre_sunday =$cur_date -(6*24*60*60)- (24*60*60);
$next_satday = $cur_date- (24*60*60);
}
$pre_sunday = date('Y-m-d',$pre_sunday)." 00:00:00";
$next_satday = date('Y-m-d',$next_satday)." 23:59:59";
$date_array = array();
$date_array['sdoflw'] = $pre_sunday;
$date_array['edoflw'] = $next_satday;
return $date_array;
}
$date_array = getlastweek_first_last_date();
echo $start_date_of_week = $date_array['sdoflw'];
echo $end_date_of_week = $date_array['edoflw'];
</code>

Answer 7

Simply you can get the date as follows
first day of week is Monday
date('Y-m-d',strtotime('Monday this week'));
if first day is Sunday
date('Y-m-d',strtotime('Sunday this week'));