Velocity Reviews > Expressing time.

# Expressing time.

Sean
Guest
Posts: n/a

 07-14-2003
I'm playing around times and dates. I'd like to determine the age of
particular sets of data in a user friendly matter.

I've got everything ready but dealing with time in a user friendly manner.

What would be a good way to express (in python):
time.localtime()+30 days
time.localtime()+5 minutes
time.localtime()+2 months
time.localtime()-2 years

I know I could probably just calculate out each of those in seconds but that
seems unelegant and very unfriendly (not to mention prone to error).

Is there any python facilities to make this an easier chore (aka
time.localtime()+months(3))?
(I included months as it is a special case in that you can't just
arbitrarily calculate months in seconds without being relative to a
particular month).

--
Sean

Eddie Corns
Guest
Posts: n/a

 07-14-2003
"Sean" <(E-Mail Removed)> writes:

>I'm playing around times and dates. I'd like to determine the age of
>particular sets of data in a user friendly matter.

>I've got everything ready but dealing with time in a user friendly manner.

>What would be a good way to express (in python):
> time.localtime()+30 days
> time.localtime()+5 minutes
> time.localtime()+2 months
> time.localtime()-2 years

>Is there any python facilities to make this an easier chore (aka
>time.localtime()+months(3))?
>(I included months as it is a special case in that you can't just
>arbitrarily calculate months in seconds without being relative to a
>particular month).

mx.DateTime makes these sort of calculations easy. I have a similarish task
in presenting users an easy way of specifying which day's log files to search
(hence in this case it was always a date in the past but the principle would
be similar). So I allow things like 'monday', 'tuesday' etc. and -n for n
days ago and several other variations. The interesting one in this instance
is:

dm_reg = re.compile (r'^(-?\d\d?)[/.](-?\d\d?)\$')
this_day = today()

# dd/mm (-ve dd means count from end of month, -mm is mm months ago)
mt = re.match (dm_reg, user_input)
if mt:
dy,mon = map(int, mt.groups())
if mon < 0:
mon = this_day.month + mon
if mon <= 0:
mon = 12 + mon
dt = DateTime (this_day.year, mon, dy)
if dt > this_day:
dt = DateTime (this_day.year-1, mon, dy)
return dt

Which allows eg 1/-2 for the first of whatever month was 2 months ago or even
-1/-1 for the last day of the previous month. mx.DateTime is doing all the
hard work. You could cook up something similar to parse eg "-2m" "+2y" etc.

Possibly the new time stuff in 2.3 will do this also, I haven't looked at 2.3
yet.

Eddie