Python: Find date beginning two months prior to today AND start on a Monday

Question

so I am a beginner with python and have been working with the datetime, time, and timedelta libraries a little bit. I am trying to create a piece of code that gives me the date approximately two months ago(exact_two_months_date) from today (whatever today happens to be). The catch is, I want to find that date approx. two months ago AND begin the actual start_date on the Monday of that week. So in theory, the actual start date will not be exactly two months ago. It will be the week beginning on Monday two months ago from today.

Example pseudocode:
    today = '20150425' ## '%Y%m%d' ... Saturday
    exact_two_months_date = '20150225' ## EXACTLY two months ago ... Wednesday
    start_date = '20150223' ## this is the Monday of that week two months ago

So how do I find the 'start_date' above? If the day exactly two months ago begins on a Saturday or Sunday, then I would just want to go to the next Monday. Hope this is clear and makes sense... Once I find the start date, I would like to increment day by day(only week days) up to 'today'.
Appreciate any feedback, thanks.

Answer 1

Calculating with dates using python-dateutil
If a dependency on a third-party package is an option, then ☞ python-dateutil provides a convenient method to calculate with dates.

Browse the docs for ☞ relativedelta to see the wealth of supported parameters. The more calculations a package needs to do with dates, the more a helper module like dateutil justifies its dependency. For more inspiration on what it has to offer see the ☞ examples page.

Quick run-through:

>>> import datetime
>>> from dateutil.relativedelta import relativedelta

>>> today = datetime.date.today()
>>> two_m_ago = today - relativedelta(months=2)
>>> # print two_m_ago ~> datetime.date(2015, 2, 25)

>>> monday = two_m_ago - datetime.timedelta(days=two_m_ago.weekday())
>>> # print monday ~> datetime.date(2015, 2, 23)

Getting the Monday with weekday()
Once we have the date from two months ago in the variable two_m_ago, we subtract the index of the weekday() from it. This index is 0 for Monday and goes all the way to 6 for Sunday. If two_m_ago already is a Monday, then subtracting by 0 will not cause any changes.