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Iterating Over Dates (Python recipe) by Michael Cornelius
ActiveState Code (http://code.activestate.com/recipes/574441/)

Iterate over a range of dates, [begin, end), day by day. By using datetime objects, rather than date object, it is possible to iterate over smaller time-granularities if desired.

Python, 31 lines
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from datetime import timedelta

def daterange(begin, end, delta = timedelta(1)):
    """Form a range of dates and iterate over them.  

    Arguments:
    begin -- a date (or datetime) object; the beginning of the range.
    end   -- a date (or datetime) object; the end of the range.
    delta -- (optional) a timedelta object; how much to step each iteration.
             Default step is 1 day.
             
    Usage:

    """
    if not isinstance(delta, timedelta):
        delta = timedelta(delta)

    ZERO = timedelta(0)

    if begin < end:
        if delta <= ZERO:
            raise StopIteration
        test = end.__gt__
    else:
        if delta >= ZERO:
            raise StopIteration
        test = end.__lt__

    while test(begin):
        yield begin
        begin += delta

In my application, interacting with a set of project management data, I needed to make changes to several days in the calendar at a time. I could have written explicit while loops, and incremented a date variable, but since I was going to be doing it several times, I extracted it to a function to improve readability and encapsulate error checking.

Tags: shortcuts