On Wed, Jan 6, 2021 at 8:02 AM Martin Schöön <martin.sch...@gmail.com> wrote: > > Hello, > > I have had some Python fun with COVID-19 data. I have done > some curve fitting and to make that easier I have transformed > date to day of year. Come end of 2020 and beginning of 2021 > and this idea falls on its face. >
There are multiple definitions for "day of year", depending on how you want to handle certain oddities. The simplest is to identify Jan 1st as 1, Jan 2nd as 2, etc, to Dec 31st as either 365 or 366; but some libraries will define the year as starting with the week that contains the Thursday, or something, and then will define days of year accordingly. If you want an easy way to graph day-by-day data and the exact day numbers are irrelevant, what I'd recommend is: Convert the date into Unix time, divide by 86400, floor it. That'll give you a Julian-style date number where Jan 1st 1970 is 0, Jan 2nd is 1, etc, and at the end of a year, it'll just keep on incrementing. That would get you past the 2020/2021 boundary pretty smoothly. ChrisA -- https://mail.python.org/mailman/listinfo/python-list
