PHP: DateInterval every two weeks in X days - php

Question

I have a start date and end date.
I'm trying to get all the Tuesdays and Wednesdays of every two weeks.
Example:
2017-05-23 (tu)
2017-05-24 (we)
2017-06-06 (tu)
2017-06-07 (we)
...
What I'm trying to do in PHP:
$start = new FrozenTime('2017-05-23'); // Date is in this format 'cause I'll save into DB
$endOfYear = $start->endOfYear();
$perWeek = new \DateInterval('P14D'); // I want every 2 weeks
$periodPerWeek = new \DatePeriod($start, $perWeek, $endOfYear);
$days = ['2', '3']; // Tuesday and Wednesday
foreach ($periodPerWeek as $value) {
if (in_array($value->format('N'), $days)) {
$test[] = [
'start' => $value
];
}
}
The results:
"start": "2017-05-23",
"start": "2017-06-06",
"start": "2017-06-20",
It's getting only one date in array. I need to get the Wednesday's too! How can I do it?
IMPORTANT:
The start date will not be always Tuesday. The user can choose the week days that he wants.
Ex:
The user can choose every SU, WE and FR in every two weeks.
// start date example: 2017-05-20 (saturday)
// output should be like:
2017-05-22 (SU)
2017-05-24 (WE)
2017-05-26 (FR)
2017-06-05 (SU)
2017-06-07 (WE)
2017-06-09 (FR)
...

Answer 1

One way to do it
/**
* #param \DateTime $start
* #param \DateTime $end
* #param array $days i.e. ['tue', 'wed', 'sat']
*
* #return array
*/
function every_two_weeks($start, $end, $days)
{
$dates = [];
$mon = new DateTime('mon this week '.$start->format('Y-m-d'));
while ($mon <= $end) {
$of = 'this week '.$mon->format('Y-m-d');
foreach ($days as $day) {
$date = new DateTime("$day $of");
if ($date < $start) {
continue;
}
if ($date > $end) {
break 2;
}
$dates[] = $date;
}
$mon->add(new DateInterval('P2W'));
}
return $dates;
}
Usage:
$start = new DateTime('2017-05-23');
$end = new DateTime('2017-06-21');
$dates = every_two_weeks($start, $end, ['tue', 'wed', 'sat']);
Output:
2017-05-23 Tue
2017-05-24 Wed
2017-05-27 Sat
2017-06-06 Tue
2017-06-07 Wed
2017-06-10 Sat
2017-06-20 Tue
2017-06-21 Wed
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