Find number of days ( comma separated ) between two dates in php - php

Question

I have comma separated days(1,3,5,6) and i want to count number of days between two days.
I have done this as below.
$days=$model->days; // comma saperated days
$days=explode(',',$days); // converting days into array
$count=0;
$start_date = $model->activity_start_date; // i.e. 2018-03-27
$end_date = date('Y-m-d');
while(strtotime($start_date) <= strtotime($end_date)){
if(in_array(date("N",strtotime($start_date)),$days)){ // check for day no
$count++;
}
$start_date = date ("Y-m-d", strtotime("+1 day", strtotime($start_date)));
}
This code is working fine. But the problem is if difference between two date will be year or more than a year than it loop 365 times or more.
Is there any way to reduce execution time to count days. Or it is possible to get counts of days using mysql query.
Real Scenario : I have one event which have start date and it occurs multiple in week(i.e. Monday and Wednesday ) and i want to find how many times event occur from start date to now. If start date is 2018-04-9 and today is 2018-05-9 than count will be 9

Answer 1

This requires no looping.
I find how many weeks between start and end and multiply full weeks (in your example 16,17,18) with count of days.
Then I find how many days there is in first week (15) that is higher than or equal to daynumber of startday.
Then the opposit for week 19.
$days="1,3"; // comma saperated days
$days=explode(',',$days); // converting days into array
$count=0;
$start_date = "2018-04-09";
$end_date = "2018-05-09";
// calculate number of weeks between start and end date
$yearW = floor(((strtotime($end_date) - strtotime($start_date)) / 86400)/7);
if($yearW >0) $count = ($yearW -1)*count($days); //full weeks multiplied with count of event days
$startday = date("N", strtotime($start_date));
$endday = date("N", strtotime($end_date));
//find numer of event days in first week (less than or equal to $startday)
$count += count(array_filter($days,function ($value) use($startday) {return ($value >= $startday);}));
//find numer of event days in last week (less than $endday)
$count += count(array_filter($days,function ($value) use($endday) {return ($value < $endday);}));
echo $count; // 9
https://3v4l.org/9kupt
Added $yearW to hold year weeks

Answer 2

Here, I have a code I have used previously in a project. It is used to find the distance between date from today.
public function diffFromToday($date){
$today = date('jS F, Y');
$today = str_replace(',','',$today);
$today=date_create($today);
$today = date_format($today,"Y-m-j");
$date = str_replace(',','',$date);
$date=date_create($date);
$date = date_format($date,"Y-m-j");
$today=date_create($today);
$date=date_create($date);
$diff=date_diff($today,$date);
$result = $diff->format("%R%a");
$result = str_replace('+','',$result);
return $result;
}
You can use this function according to your requirement. Date format used in this function is 'jS F, Y' DO not be confused and use your own format to convert.

Answer 3

$start_date = date_create('2018-03-27');
$end_date = date_create('2018-04-27');
$t = ceil(abs($endDate- $start_date) / 86400);
echo date_diff($start_date, $end_date)->format('%a');
Output with like this
396

Answer 4

Could you not use the date->diff function to get the values you can directly use like -5 or 5?
$diffInDays = (int)$dDiff->format("%r%a");
Here is something for format parameter descriptions if it could be helpful to you.

Answer 5

You may use tplaner/when library for this:
$days = str_replace(
['1', '2', '3', '4', '5', '6', '0', '7'],
['mo', 'tu', 'sa', 'th', 'fr', 'sa', 'su', 'su'],
'1,3'
);
$when = new When();
$when->rangeLimit = 1000;
$occurrences = $when->startDate(new DateTime('2018-04-9'))
->freq('daily')
->byday('mo,we')
->getOccurrencesBetween(new DateTime('2018-04-9'), new DateTime('2018-05-9'));
echo count($occurrences);