The start of a cartesian job runner.

cartesian_job.py

def partition(start, end, step):
    '''
    Partitions the interval [start, end) into 'k' intervals [a_i, a_{i+1}).
    '''
    from itertools import takewhile, chain, islice, tee

    # itertools.count does not work with datetime.
    def count(firstval=0, step=1):
        x = firstval
        while 1:
            yield x
            x += step

    assert(start_date < end_date)

    a_i = takewhile(lambda x: x < end, count(start, step))
    a_i = tee(a_i)
    a_ip1 = chain(islice(a_i[0], 1, None), [end])
    return zip(a_i[1], a_ip1)

Usage

from itertools import product
from datetime import datetime, timedelta

start_date = datetime.strptime(input(prompt='Start Date YYYY/MM/DD: '), '%Y/%m/%d')
end_date = datetime.strptime(input(prompt='End Date YYYY/MM/DD: '), '%Y/%m/%d')

with open(selectors_filepath, 'r') as selectors:
    intervals = partition(start_date, end_date, 
                           timedelta(days=60))
    for (interval, sel) in product(intervals, selectors):
        print('{}: [{}, {})'.format(sel, *interval))