weekdays in range

[Dave Angel]

Jive Dadson wrote:
> <div class="moz-text-flowed" style="font-family: -moz-fixed">Wow.  
> It's a danged tutorial.  Thanks again.  Take a break.
>
> </div>
>
Ben Finney's method is a very good approach, and an experienced Python 
programmer would consider it straightforward.

But I have to ask whether the range of dates you might be considering 
could be large.  For example, if you want to know how many week-days 
there are between a date in 1904 and 2207, it'd build a list of some 110 
thousand items.  There are other approaches which would be faster, 
consume much less memory, and be much harder to read.


I'm not offering to debug it, but here's such an approach, subject to 
the old plus/minus one bugs.

def epochweekdays (datetimeobj)
      """Given an arbitrary Monday long ago, figure out how many 
weekdays have occurred between that day and the argument"""
      subtract to get total_days
      return int(totaldays/7) * 5   + max(totaldays%7, 5)

Now, your answer is just
    epochweekdays(b) - epochweekdays(a)

DaveA