Getting week numbers for last X weeks - php

Question

I have a script that builds an array of week numbers for the last 12 weeks like so:
$week_numbers = range(date('W'), date('W')-11, -1);
However, if the current week number is 1, then this will return an array like so:
Array
(
[0] => 1
[1] => 0
[2] => -1
[3] => -2
[4] => -3
[5] => -4
[6] => -5
[7] => -6
[8] => -7
[9] => -8
[10] => -9
[11] => -10
)
But I need this array to look like this instead:
Array
(
[0] => 1
[1] => 52
[2] => 51
[3] => 50
[4] => 49
[5] => 48
[6] => 47
[7] => 46
[8] => 45
[9] => 44
[10] => 43
[11] => 42
)
Can anyone see a simple solution to this?
I have thought about doing something like this (not tested):
$current_week_number = date('W');
if($current_week_number<12){
// Calculate the first range of week numbers (for current year)
$this_year_week_numbers = range(date('W'), 1, -1);
// Calculate the next range of week numbers (for last year)
$last_year_week_numbers = range(52, 52-(11-$current_week_number), -1);
// Combine the two arrays to return the week numbers for the last 12 weeks
$week_numbers = array_merge($this_year_week_numbers,$last_year_week_numbers);
}else{
// Calculate the week numbers the easy way
$week_numbers = range(date('W'), date('W')-11, -1);
}

Answer 1

one idea
$i = 1;
while ($i <= 11) {
echo date('W', strtotime("-$i week")); //1 week ago
$i++;
}

Answer 2

if you arent scared of loops you can do this:
$week_numbers = range(date('W'), date('W')-11, -1);
foreach($week_numbers as $key => $value) { if($value < 1) $week_numbers[$key] += 52; }

Answer 3

You can do a modulo % trick:
$week_numbers = range(date('W'), date('W')-11, -1);
foreach ($week_numbers as $i => $number) {
$week_numbers[$i] = (($week_numbers[$i] + 52 - 1) % 52) + 1;
}
// -1 +1 is to change the range from 0-51 to 1-52
I've found that using modulo like this is often useful for date calculations, you can something similar for months, using 12.

Answer 4

Well, I think the easiest way is to create array after getting dates:
$week_numbers = array_map(function($iDay)
{
return ($iDay+52)%52?($iDay+52)%52:52;
}, range(date('W'), date('W')-11));
-note, that you can not do just % since 52%52 will be 0 (and you want 52)