Core Concepts

When-Exactly is basically a wrapper around Python's already awesome datetime module, and allows developers to work with dates in a more abstract way.

Moment

The Moment represents, a moment in time. This is analogous to Python's datetime.datetime class.

>>> moment = we.Moment(
...     year=2025,
...     month=3,
...     day=14,
...     hour=15,
...     minute=0,
...     second=0,
... )
>>> str(moment)
'2025-03-14T15:00:00'

Delta

The Delta is analogous to Python's datetime.timedelta, with extra functionality for deltas of years and months.

>>> delta = we.Delta(
...    years=1,
...    months=1,
...    weeks=2,
... )
>>> moment + delta
Moment(year=2026, month=4, day=28, hour=15, minute=0, second=0)

Interval

An Interval represents a time span. An interval has an inclusive start and an exclusive stop.

>>> interval = we.Interval(
...     start=we.Moment(2025, 2, 14, 12, 0, 0,),
...     stop=we.Moment(2025, 2, 14, 12, 30, 0),
... )
>>> str(interval)
'2025-02-14T12:00:00/2025-02-14T12:30:00'

Custom Interval

A CustomInterval represents a time span with a specific resolution.

This is the building block of all the custom intervals like Year, Month, etc.

Collection

The Collection represents a collection of Interval objects. It provides all of the standard functionality you would expect a container to have

>>> collection = we.Collection([
...    we.Day(2023, 1, 5),
...    we.Day(2023, 1, 7),
...    we.Week(2023, 10),
... ])
>>> collection[0]
Day(2023, 1, 5)

>>> collection[0:2]
Collection([Day(2023, 1, 5), Day(2023, 1, 7)])

>>> we.Week(2023, 10) in collection
True

>>> for interval in collection:
...     print(interval)
2023-01-05
2023-01-07
2023-W10