Calculating workday deadline dates

[jworisek]

I'm looking into a way to computerize deadlines for our orders. At the moment a user manually enters the date by checking a cheat sheet and using a calendar to figure out when the deadline is. My problem is that I only want to use weekdays in the calculation.

For instance we might get an order we can ship in 3 days.. if we get it on a friday, I want to be able to say we will ship on the following wednesday. Some may have up to 2 month deadlines.

At the moment all I can think of is doing a rough calculation including weekends then going back through and taking out the weekends and adding that time back on... Although that will get tricky as well since I will have to loop through that possibly 3 times.

Anybody have any ideas on an easier way?

[jworisek]

well I have something like:

[code]
<?
$today=mktime();  //todays date in seconds
$one_day=24*60*60;  //one day in seconds
$target_days=5;  //5 work days
$days_used=0;

while ($days_used<$target_days){
  $day=date("w",$today);  
  if (($day==0)||($day==6)){
    $today=$today+$one_day;
  }
  else{
    $today=$today+$one_day;
  $days_used++;
  }
}
?>
[/code]

It will work, but I'm sure there is a more efficient way.

[Barand]

Instead of looping through days on each of the 3 calls

[code]  // create array of weekdays
  // only loop once instead of 3 times
$weekdays = array();
for ($d=0; $d<70; $d++) {
    $day = strtotime("+$d days");
    $dow = date('w', $day);
    if ($dow != 0 && $dow != 6) {
        $weekdays[] = $day;
    }
}

$target_days=5;  //5 work days
$ship_date = date ('D d M Y', $weekdays[$target_days]);

echo $ship_date;
[/code]

[jworisek]

In my code the most I would have is 7 iterations whereas yours will always have 70 iterations... The one I posted was different from my first thought where I might have to go back through and take out the weekends afterwords. Instead I figured it was easiest just to step through one day at a time and ignore weekends as I go. I could be wrong but that seems a lot more efficient than always pulling the max amount of days to check.

[Barand]

[!--quoteo(post=378508:date=May 30 2006, 09:30 PM:name=jworisek)--][div class=\'quotetop\']QUOTE(jworisek @ May 30 2006, 09:30 PM) [snapback]378508[/snapback][/div][div class=\'quotemain\'][!--quotec--]
Some may have up to 2 month deadlines.

........ since I will have to loop through that possibly 3 times.
[/quote]

In which case 180+ iterations