overlapping dates between two date ranges in python

Question

I'm looking to find overlapping dates between two dates ranges as the following:

range1 = start(2016-06-01) end (2016-06-20)
range2 = start(2016-06-10) end (2016-06-13)

result here is 4 dates (2016-06-10,2016-06-11,2016-06-12,2016-06-13). another example:

 range1 = start(2016-06-01) end (2016-06-20) range2 = start(2016-06-18)
 end (2016-06-25)

result here is 3 dates (2016-06-18,2016-06-19,2016-06-20). and if no dates overlap then the result is 0 dates.

I found this post its helpful in determining the number of overlapping dates but I was wondering if I can get the actual dates without using long if/else statements?

Thanks in advance!

Answer 1

I would suggest generating the dates in each of both ranges, then selecting the intersection between the two set. A snipped doing so may look like this:

from datetime import date, timedelta


def f(d1, d2):
    delta = d2 - d1
    return set([d1 + timedelta(days=i) for i in range(delta.days + 1)])

range1 = [date(2016, 6, 1), date(2016, 6, 20)]
range2 = [date(2016, 6, 10), date(2016, 6, 13)]

print f(*range1) & f(*range2)

For performance purposes you can also cast d1 + timedelta(days=i) to str while generating the dates in a given range.