Comparing dates problem

[Tim Golden]

kyosohma at gmail.com wrote:
> I am writing a reminder program for our Zimbra email client. One of
> the requirements I was given was to automatically increment or
> decrement the display to show something like the following:
> 
> 5 minutes until appointment
> 
> or
> 
> 10 minutes past your appointment
> 
> 
> Either way, as each minute goes by, I need to increment it or
> decrement it. I am having trouble finding a coherent way to take the
> same date and compare just the number of minutes between them to find
> the difference. Like if I have an appointment at 9:30 a.m. and the app
> is loaded at 8 a.m., I need to know the number of minutes or hours and
> minutes until the appointment.

Not the most elegant piece of code on earth,
but this piece of code works for me (cut-and-pasted
directly from a working project, so doesn't
*exactly* match your requirement).

<code>
def deltastamp (now, then):

   def pluralise (base, n):
     if n > 1:
       return "%d %ss" % (n, base)
     else:
       return "%d %s" % (n, base)

   if now > then:
     output_format = "%s ago"
     delta = now - then
   else:
     output_format = "in %s"
     delta = then - now

   days = delta.days
   if days <> 0:
     wks, days = divmod (days, 7)
     if wks > 0:
       output = pluralise ("wk", wks)
     else:
       output = pluralise ("day", days)
   else:
     mins, secs = divmod (delta.seconds, 60)
     hrs, mins = divmod (mins, 60)
     if hrs > 0:
       output = pluralise ("hr", hrs)
     elif mins > 0:
       output = pluralise ("min", mins)
     else:
       output = pluralise ("sec", secs)

   return output_format % output

</code>

TJG