MonthDay

final class whenever.MonthDay(iso_string: str, /)

final class whenever.MonthDay(month: int, day: int)

A month and day without a year component.

Useful for representing recurring annual events such as birthdays, holidays, or anniversaries.

>>> md = MonthDay(11, 23)
MonthDay("--11-23")

Can also be constructed from an ISO 8601 string:

>>> MonthDay("--11-23")
MonthDay("--11-23")

classmethod parse_iso(s: str, /) → MonthDay

Create from the ISO 8601 format --MM-DD or --MMDD.

Inverse of format_iso()

>>> MonthDay.parse_iso("--11-23")
MonthDay("--11-23")

__eq__(other: object) → bool

Compare for equality

>>> md = MonthDay(10, 1)
>>> md == MonthDay(10, 1)
True
>>> md == MonthDay(10, 2)
False

__ge__(other: MonthDay) → bool

Return self>=value.

__gt__(other: MonthDay) → bool

Return self>value.

__le__(other: MonthDay) → bool

Return self<=value.

__lt__(other: MonthDay) → bool

Return self<value.

__str__() → str

Format as the ISO 8601 month-day format.

Inverse of parse_iso.

>>> MonthDay(10, 8).format_iso()
'--10-08'

Note

This format is officially only part of the 2000 edition of the ISO 8601 standard. There is no alternative for month-day in the newer editions. However, it is still widely used in other libraries.

format_iso() → str

Format as the ISO 8601 month-day format.

Inverse of parse_iso.

>>> MonthDay(10, 8).format_iso()
'--10-08'

Note

This format is officially only part of the 2000 edition of the ISO 8601 standard. There is no alternative for month-day in the newer editions. However, it is still widely used in other libraries.

in_year(year: int, /) → Date

Create a date from this month-day with a given day

>>> MonthDay(8, 1).in_year(2025)
Date("2025-08-01")

Note

This method will raise a ValueError if the month-day is a leap day and the year is not a leap year.

is_leap() → bool

Check if the month-day is February 29th

>>> MonthDay(2, 29).is_leap()
True
>>> MonthDay(3, 1).is_leap()
False

replace(month: int = ..., day: int = ...) → MonthDay

Create a new instance with the given fields replaced

>>> d = MonthDay(11, 23)
>>> d.replace(month=3)
MonthDay("--03-23")

MAX: ClassVar[MonthDay] = MonthDay("--12-31")

The maximum possible month-day

MIN: ClassVar[MonthDay] = MonthDay("--01-01")

The minimum possible month-day

property day: int

The day component of the month-day

>>> MonthDay(11, 23).day
23

property month: int

The month component of the month-day

>>> MonthDay(11, 23).month
11