PHP date calculation

Question

What is the best (date format independent way) in PHP to calculate difference in days between two dates in specified format.

I tried the following function:

function get_date_offset($start_date, $end_date)
{
  $start_time = strtotime($start_date);
  $end_time = strtotime($end_date);
  return round(($end_time-$start_time)/(3600*24));
}

It works ok on linux box, but when running under windows strtotime returns ''.

EDIT:

Input date is in mm/dd/yyyy format, but I would like to make it accept $format as a parameter.

I need only difference in days.

Answer 1

If you do not want or you cannot use Zend Framework or Pear package try this function i hope this would help:

function dateDifference($date1, $date2)
{
    $d1 = (is_string($date1) ? strtotime($date1) : $date1);
    $d2 = (is_string($date2) ? strtotime($date2) : $date2);

    $diff_secs = abs($d1 - $d2);
    $base_year = min(date("Y", $d1), date("Y", $d2));

    $diff = mktime(0, 0, $diff_secs, 1, 1, $base_year);

    return array
    (
        "years"         => abs(substr(date('Ymd', $d1) - date('Ymd', $d2), 0, -4)),
        "months_total"  => (date("Y", $diff) - $base_year) * 12 + date("n", $diff) - 1,
        "months"        => date("n", $diff) - 1,
        "days_total"    => floor($diff_secs / (3600 * 24)),
        "days"          => date("j", $diff) - 1,
        "hours_total"   => floor($diff_secs / 3600),
        "hours"         => date("G", $diff),
        "minutes_total" => floor($diff_secs / 60),
        "minutes"       => (int) date("i", $diff),
        "seconds_total" => $diff_secs,
        "seconds"       => (int) date("s", $diff)
    );
}