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I have two date ranges where each range is determined by a start and end date (obviously, datetime.date() instances). The two ranges can overlap or not. I need the number of days of the overlap. Of course I can pre-fill two sets with all dates within both ranges and the perform a set intersection but this is possibly inefficient...is there a better way apart from another solution using a long if-elif section covering all cases ?
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You can do this by swapping the ranges if necessary up front. Then, you can detect overlap if the second range start is: less than or equal to the first range end (if ranges are inclusive, containing both the start and end times); or. less than (if ranges are inclusive of start and exclusive of end).
You can also look for overlapping data in sets by using the . intersection() method on a set and passing another set as an argument. It will return an empty set if nothing matches.
overlaps() method is used to Check whether Interval objects are overlapping. Two intervals, including closed ends, overlap if they share the same point.
Here is an example calculation:
>>> from datetime import datetime >>> from collections import namedtuple >>> Range = namedtuple('Range', ['start', 'end']) >>> r1 = Range(start=datetime(2012, 1, 15), end=datetime(2012, 5, 10)) >>> r2 = Range(start=datetime(2012, 3, 20), end=datetime(2012, 9, 15)) >>> latest_start = max(r1.start, r2.start) >>> earliest_end = min(r1.end, r2.end) >>> delta = (earliest_end - latest_start).days + 1 >>> overlap = max(0, delta) >>> overlap 52 If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
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