Question

Let’s say I have a variable time_period, with a value of one of the following strings: weekly, monthly, yearly.

…and a QuerySet call filtering through a model TimeModel:

time_period = 'monthly'
instance = TimeModel.objects.get(time_period=time_period,
                                 year=datetime.now().year,
                                 month=datetime.now().month)

In this case, I’ve passed the parameters year and month in, because time_period == 'monthly'. If time_period == yearly, I would want to only pass year, and if time_period == weekly, I would pass all three (yearly, monthly, and weekly) in.

Is there any way of doing what I’ve described short of writing 3 if statements?

Answer 1

Maybe this helps:

from django.db.models import Q

now = datetime.now()
time_periods = {
    'weekly': Q(year=now.year, month=now.month, day=now.week),  # note from OP: now.week is technically invalid; you actually want to use now.isocalendar()[1]
    'monthly': Q(year=now.year, month=now.month),
    'yearly': Q(year=now.year),
}

instance = TimeModel.objects.get(time_periods[time_period], time_period=time_period)