["python","date","datetime","iteration","date-range"]
Iterating through a range of dates in Python

I have the following code to do this, but how can I do it better? Right now I think it's better than nested loops, but it starts to get Perl-one-linerish when you have a generator in a list comprehension. day_count = (end_date - start_date).days + 1 for single_date in [d for d in (start_date + timedelta(n) for n in range(day_count)) if d <= end_date]: print strftime("%Y-%m-%d", single_date.timetuple()) Notes I'm not actually using this to print. That's just for demo purposes. The start_date and end_date variables are datetime.date objects because I don't need the timestamps. (They're going to be used to generate a report). Sample Output For a start date of 2009-05-30 and an end date of 2009-06-09: 2009-05-30 2009-05-31 2009-06-01 2009-06-02 2009-06-03 2009-06-04 2009-06-05 2009-06-06 2009-06-07 2009-06-08 2009-06-09
Why are there two nested iterations? For me it produces the same list of data with only one iteration: for single_date in (start_date + timedelta(n) for n in range(day_count)): print ... And no list gets stored, only one generator is iterated over. Also the "if" in the generator seems to be unnecessary. After all, a linear sequence should only require one iterator, not two. Update after discussion with John Machin: Maybe the most elegant solution is using a generator function to completely hide/abstract the iteration over the range of dates: from datetime import date, timedelta def daterange(start_date: date, end_date: date): days = int((end_date - start_date).days) for n in range(days): yield start_date + timedelta(n) start_date = date(2013, 1, 1) end_date = date(2015, 6, 2) for single_date in daterange(start_date, end_date): print(single_date.strftime("%Y-%m-%d")) NB: For consistency with the built-in range() function this iteration stops before reaching the end_date. So for inclusive iteration use the next day, as you would with range().