Question

This is a bit difficult to explain, so I apologize if this doesn’t make much sense.

I have a program where I am doing some scheduling. One of the settings it has is to run a task weekly on certain days. For example, weekly on Monday, Wednesday and Friday.

Consider the example where the current task is scheduled for 1/2/2012, which is a Monday, I already have a bunch of code working to the point where I know the next task run should be on the wednesday following 1/2/2012. All I need to do is calculate the actual date of that Wednesday (1/4/2012).

I actually have the day of the week as the corresponding integer from date.weekday(), so in this case I have 2 which represents wednesday.

Whats the best way to handle something like this? I feel like there should be a fairly simple solution, but it isn’t coming to mind. I was thinking of using a calendar object to search through to find the day of the week I want, but that seems like overkill.

Answer 1

Use a timedelta to add to a date. For example, using some date d as the scheduled date for a current task, and some day next_day (the next day you’d like to run the task).

from datetime import date, timedelta
...
n = (next_day - d.weekday()) % 7 # mod-7 ensures we don't go backward in time
next_run_date = d + timedelta(days=n)