How many calendar days elapsed since given date?

Question

I need to find how many calendar days elapsed sice given date. When I use the following, it gives me -1 even when the date is today:

>>> from datetime import datetime
>>> t = datetime.fromisoformat('2023-03-09 08:55:11')
>>> (t - datetime.today()).days
-1

Whereas the correct answer should be 0.

If I ask at 00:00:01, and the date was yesterday at 23:59:59, it should give me 1 day. But anything today should be 0.

How can I do that?

Asked By: 400 the Cat

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Source

Answer 1

The reason you are getting a negative result is that you are subtracting the current date from a future date. You can use math.abs, or just:

t= datetime.fromisoformat('2023-03-01')
elapsed_days = (datetime.today() - t).days
print(elapsed_days)

Answered By: Surstreem

Answer 2

from datetime import datetime, date

given_date = datetime.fromisoformat('2023-03-09 08:55:11')
today = datetime.now().date() # get current date without time
elapsed_days = (today - given_date.date()).days

print(elapsed_days)

Answered By: JABRI

Answer 3

Convert both values to dates instead of datetimes.

It’s like comparing 0.9 to 1.1 and wanting the result to be 1. Converting them both to integers first would give 0 and 1 with a difference of 1.

So, compare dates, not datetimes…

from datetime import datetime, date

x = datetime.fromisoformat('2023-03-09 08:55:11')
y = datetime.fromisoformat('2023-03-10 07:00:00')

print((y - x).days)
print((y.date() - x.date()).days)
print()

y = datetime.fromisoformat('2023-03-10 09:00:00')
print((y - x).days)
print((y.date() - x.date()).days)

Demo : https://trinket.io/python3/013ac6c02a

Answered By: MatBailie

How many calendar days elapsed since given date?

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