Finding the day x years,months from a given time (Python)

Question

Have a maths question here which I know to solve using only pen and paper. Takes a while with that approach, mind you. Does anybody know to do this using Python? I've done similar questions involving "dates" but none involving "days". Any of you folk able to figure this one out?

The date on 25/11/1998 is a Wednesday. What is the day on 29/08/2030?

Can anyone at least suggest an algorithm?

Cheers

Please don't use both [python-2.7] and [python-3.x] tags. If the version is irrelevant, use neither. — Wooble, Sep 24 '13 at 23:49
Do you actually need an algorithm to do this yourself (for a class, because you need dates outside the limit of `str[pf]time`, whatever…)? Or is Haidro's answer all you need? — abarnert, Sep 24 '13 at 23:52

score 2 · Answer 1 · answered Sep 24 '13 at 23:48

2

Use the wonderful datetime module:

>>> import datetime
>>> mydate = datetime.datetime.strptime('29/08/2030', '%d/%M/%Y')
>>> print mydate.strftime('%A')
Tuesday

answered Sep 24 '13 at 23:48

TerryA

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That's kind of cheating. :) – Wooble Sep 24 '13 at 23:48
6

@Wooble Welcome to Python – TerryA Sep 24 '13 at 23:49
This doesn't actually say how to get the date X years, Y months from a given time. For that, you might need an extra line of code! :) – abarnert Sep 25 '13 at 00:16
@abarnert Oh yea. We'll wait for the OP I guess – TerryA Sep 25 '13 at 00:19

score 0 · Answer 2 · answered Sep 25 '13 at 04:08

The algorithm/math is quite simple: There are always 7 days a week. Just calculate how many days between the two days, add it to the weekday of the given day then mod the sum by 7.

<!-- language: python -->
> from datetime import datetime
> given_day = datetime(1998,11,25)
> cal_day = datetime(2030,8,29)
> print cal_day.weekday()
 3
> print (given_day.weekday() + (cal_day-given_day).days) % 7
 3

Finding the day x years,months from a given time (Python)

2 Answers2