numpy.typing.NBitBase

class NBitBase:

Known subclasses: numpy.typing._256Bit

A type representing numpy.number precision during static type checking.

Used exclusively for the purpose static type checking, NBitBase represents the base of a hierarchical set of subclasses. Each subsequent subclass is herein used for representing a lower level of precision, e.g. 64Bit > 32Bit > 16Bit.

New in version 1.20.

Examples

Below is a typical usage example: NBitBase is herein used for annotating a function that takes a float and integer of arbitrary precision as arguments and returns a new float of whichever precision is largest (e.g. np.float16 + np.int64 -> np.float64).

>>> from __future__ import annotations
>>> from typing import TypeVar, TYPE_CHECKING
>>> import numpy as np
>>> import numpy.typing as npt

>>> T1 = TypeVar("T1", bound=npt.NBitBase)
>>> T2 = TypeVar("T2", bound=npt.NBitBase)

>>> def add(a: np.floating[T1], b: np.integer[T2]) -> np.floating[T1 | T2]:
...     return a + b

>>> a = np.float16()
>>> b = np.int64()
>>> out = add(a, b)

>>> if TYPE_CHECKING:
...     reveal_locals()
...     # note: Revealed local types are:
...     # note:     a: numpy.floating[numpy.typing._16Bit*]
...     # note:     b: numpy.signedinteger[numpy.typing._64Bit*]
...     # note:     out: numpy.floating[numpy.typing._64Bit*]