Class BaseCFTimeOffset

xarray/coding/cftime_offsets.py:108–197

class BaseCFTimeOffset:
    _freq: ClassVar[str | None] = None
    _day_option: ClassVar[DayOption | None] = None
    n: int

    def __init__(self, n: int = 1) -> None:
        if not isinstance(n, int):
            raise TypeError(
                "The provided multiple 'n' must be an integer. "
                f"Instead a value of type {type(n)!r} was provided."
            )
        self.n = n

    def rule_code(self) -> str | None:
        return self._freq

    def __eq__(self, other: object) -> bool:
        if not isinstance(other, BaseCFTimeOffset):
            return NotImplemented
        return self.n == other.n and self.rule_code() == other.rule_code()

    def __ne__(self, other: object) -> bool:
        return not self == other

    def __add__(self, other):
        return self.__apply__(other)

    def __sub__(self, other):
        if TYPE_CHECKING:
            import cftime
        else:
            cftime = attempt_import("cftime")

        if isinstance(other, cftime.datetime):
            raise TypeError("Cannot subtract a cftime.datetime from a time offset.")
        elif type(other) is type(self):
            return type(self)(self.n - other.n)
        else:
            return NotImplemented

    def __mul__(self, other: int) -> Self:
        if not isinstance(other, int):
            return NotImplemented
        return type(self)(n=other * self.n)

    def __neg__(self) -> Self:
        return self * -1

    def __rmul__(self, other):
        return self.__mul__(other)

    def __radd__(self, other):
        return self.__add__(other)

    def __rsub__(self, other):
        if isinstance(other, BaseCFTimeOffset) and type(self) is not type(other):
            raise TypeError("Cannot subtract cftime offsets of differing types")
        return -self + other