LA_ LA_ - 3 months ago 8
Python Question

How to get last Friday?

The code below should return last Friday, 16:00:00. But it returns Friday of previous week. How to fix that?

now = datetime.datetime.now()
test = (now - datetime.timedelta(days=now.weekday()) + timedelta(days=4, weeks=-1))
test = test.replace(hour=16,minute=0,second=0,microsecond=0)


Upd. I use the following approach now - is it the best one?

now = datetime.datetime.now()
if datetime.datetime.now().weekday() > 4:
test = (now - datetime.timedelta(days=now.weekday()) + timedelta(days=4))
else:
test = (now - datetime.timedelta(days=now.weekday()) + timedelta(days=4, weeks=-1))
test = test.replace(hour=16,minute=0,second=0,microsecond=0)


Upd2. Just to give an example. Let's assume that today is Oct 5, 2012. In case current time is equal to or less than 16:00 it should return Sep 28, 2012, otherwise - Oct 5, 2012.

Answer

As in the linked question, you need to use datetime.date objects instead of datetime.datetime. To get a datetime.datetime in the end, you can use datetime.datetime.combine():

import datetime

current_time = datetime.datetime.now()

# get friday, one week ago, at 16 o'clock
last_friday = (current_time.date()
    - datetime.timedelta(days=current_time.weekday())
    + datetime.timedelta(days=4, weeks=-1))
last_friday_at_16 = datetime.datetime.combine(last_friday, datetime.time(16))

# if today is also friday, and after 16 o'clock, change to the current date
one_week = datetime.timedelta(weeks=1)
if current_time - last_friday_at_16 >= one_week:
    last_friday_at_16 += one_week