Split the date range by days and make list of list date interval with Python

Firstly, decompose this into two steps:

1. Generate every day from one date to another
2. Convert a list [a,b,c,d] into pairs [[a,b],[c,d]]

For the first step, there is an answer here: Iterating through a range of dates in Python in which the following generator is defined:

from datetime import timedelta, date

def daterange(start_date, end_date):
    for n in range(int ((end_date - start_date).days)):
        yield start_date + timedelta(n)

If we then pair those using this definition from the itertools documentation:

def grouper(iterable, n, fillvalue=None):
    "Collect data into fixed-length chunks or blocks"
    # grouper('ABCDEFG', 3, 'x') --> ABC DEF Gxx"
    args = [iter(iterable)] * n
    return zip_longest(*args, fillvalue=fillvalue)

So then we can compose those together to make the required generator:

daypairs = grouper(daterange(start_date, end_date), 2)

And listify it thus:

daypairslist = list(daypairs)

etc.