Comparing dates problem

[kyosohma]

Hi,

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.

I have looked at the dateutils module and it has many comparison
methods, but they seem to only return the number of days or seconds.

Any ideas would be great!

Mike

 

[John Machin]

Hi,

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.

I have looked at the dateutils module and it has many comparison
methods, but they seem to only return the number of days or seconds.

Ermmm ... what's wrong with

minutes = seconds / 60.0
hours = minutes / 60.0

?

 

[Tim Golden]

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

 

[kyosohma]

Ermmm ... what's wrong with

minutes = seconds / 60.0
hours = minutes / 60.0

?

I'm sure there is a hack for doing something like what you suggest,
but it would be messy. The problem is that I get a datetime object
returned and division really isn't something you can do to one of
those objects. Besides, if I had seconds returned, I would want to
multiply by 60, not divide.

Maybe I misunderstand you.

Mike

 

[kyosohma]

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

Thanks for the advice. I think this will work for me with some minor
tweaking. If not, I will post again.

Mike

 

[Carsten Haese]

I'm sure there is a hack for doing something like what you suggest,
but it would be messy. The problem is that I get a datetime object
returned and division really isn't something you can do to one of
those objects. Besides, if I had seconds returned, I would want to
multiply by 60, not divide.

If you subtract that datetime object from the current datetime, you'll
get a timedelta object that gives you the number of days and seconds
(and microseconds, if you care) between the two datetimes:
11219

Now, if 60 seconds are one minute, 11219 seconds are how many minutes?
(Answer left as an exercise for the reader.)

Hope this helps,

 

[kyosohma]

I'm sure there is a hack for doing something like what you suggest,
but it would be messy. The problem is that I get a datetime object
returned and division really isn't something you can do to one of
those objects. Besides, if I had seconds returned, I would want to
multiply by 60, not divide.

Maybe I misunderstand you.

Mike

Of course, after posting this, I felt very stupid...

 

[John Machin]

I'm sure there is a hack for doing something like what you suggest,
but it would be messy. The problem is that I get a datetime object
returned and division really isn't something you can do to one of
those objects. Besides, if I had seconds returned, I would want to
multiply by 60, not divide.

Maybe I misunderstand you.

Maybe it's mutual -- hack? messy? multiply? Where I come from, 180
seconds is (180 / 60 = 3) minutes. 180 seconds * 60 is 10800 sixtieths-
of-a-second, which appears to be travelling away from a solution to
your problem.

You have *TWO* datetime objects, (say) appt_dt and now_dt.

delta =appt_dt - now_dt # delta is a timedelta object.
# calculate difference in minutes
mins = delta.days * 24 * 60 + delta.seconds // 60

Have you not read Tim Golden's response?

 

[kyosohma]

Maybe it's mutual -- hack? messy? multiply? Where I come from, 180
seconds is (180 / 60 = 3) minutes. 180 seconds * 60 is 10800 sixtieths-
of-a-second, which appears to be travelling away from a solution to
your problem.

You have *TWO* datetime objects, (say) appt_dt and now_dt.

delta =appt_dt - now_dt # delta is a timedelta object.
# calculate difference in minutes
mins = delta.days * 24 * 60 + delta.seconds // 60

Have you not read Tim Golden's response?

Yeah. I said I felt stupid. I'm sorry. I was looking at the problem
from the wrong direction.

Mike