Option for day the week starts on week_of_year

[yardensachs]

As you know,
A week can start either on a Monday or Sunday (maybe even other days).

Python has that feature already done with strftime:

• %U Sunday as the first day of the week.
• %W Monday as the first day of the week.

dt = datetime.datetime(2016, 10, 30)

print(dt.strftime("%U"))
 '44'

print(dt.strftime("%W"))
 '43'

Pendulum's week_of_year currently uses datetime's isocalandar (docs "week starts on a Monday and ends on a Sunday").

There needs to be a way to have both Sunday and Monday as an option because its not consistent across software (e.g. MySQL which uses Sunday). and also, why not have it if python supports it.

I would submit a pull request myself, but this is a design problem because its a property and not a function, so no args possible.

What do you think?

[yardensachs]

Also,
day_of_week uses a "Sunday is the first day" approach since its using python %w to determine.

[sdispater]

First of all, the strftime method also works with pendulum:

>>> import pendulum
>>> dt = pendulum.create(2016, 10, 30)
>>> dt.strftime("%U")
'44'
>>> dt.strftime("%W")
'43'

You can use the set_week_starts_at() method on the Pendulum class to change the day a week starts at. It will not fix properties like week_of_year and day_of_week however.

I will see if I can fix this somehow.

[SeanDunford]

Was there ever a resolution to this?

[yardensachs]

dont think so

[kokon]

If anyone else stumbled onto this, I found that you can do:

>>> import pendulum
>>> dt = pendulum.now()
>>> dt
DateTime(2019, 12, 13, 9, 39, 20, 327110, tzinfo=Timezone(''))

>>> dt.start_of('week')     # Monday
DateTime(2019, 12, 9, 0, 0, 0, tzinfo=Timezone(''))
>>> pendulum.week_starts_at(pendulum.SUNDAY)
>>> dt.start_of('week')     # Sunday
DateTime(2019, 12, 8, 0, 0, 0, tzinfo=Timezone(''))