检查时间范围内是否存在闰日

How to check if there is a February 29th in between 2 timestamps?

$date_from = '2007-06-01';
$date_to = '2013-05-30';

I know in this range there's 2 times a feb-29, but how do I check for it?

I want to count the days in between, but leap days don't count.

This will loop through the years, but it is even easier after you find a leap year because the next one will be 4 years after, etc.

$date_from = strtotime('2007-06-01');
$date_to = strtotime('2013-05-30');

for($year=$date_from; $year<=$date_to; $year=strtotime('next year', $year)) {
    echo date('Y', $year);
    echo date('L', $year) ? 'Leap year' : 'Not leap year';
}

But I think you can just check if the year 'Y' is evenly divisible by 4.

The problem I had was I wanted to find if Feb 29 existed in a smaller date range. It assumes that there is not more than two years. This my solution for that:

$startDate = strtotime('2015-10-01 00:00:00');
$endDate = strtotime('2016-09-30 23:00:00');
$feb29StartYear = mktime(0, 0, 0, 2, 29, date('Y', $startDate));
$feb29EndYear = mktime(0, 0, 0, 2, 29, date('Y', $endDate));

if( (date('L', $startDate) && $startDate < $feb29StartYear) || 
    (date('L', $endDate) && $endDate > $feb29EndYear)) { //We have a leap day
     //some logic here
}

Just thought this may be useful for someone else.