Module « typing » Python 3.11.3

Classe « TypeVar »

Informations générales

Héritage

builtins.object
    _PickleUsingNameMixin
builtins.object
    _BoundVarianceMixin
builtins.object
    _Immutable
builtins.object
    _Final
        TypeVar

Définition

class TypeVar(_Final, _Immutable, _BoundVarianceMixin, _PickleUsingNameMixin):

help(TypeVar)

Type variable.

    Usage::

      T = TypeVar('T')  # Can be anything
      A = TypeVar('A', str, bytes)  # Must be str or bytes

    Type variables exist primarily for the benefit of static type
    checkers.  They serve as the parameters for generic types as well
    as for generic function definitions.  See class Generic for more
    information on generic types.  Generic functions work as follows:

      def repeat(x: T, n: int) -> List[T]:
          '''Return a list containing n references to x.'''
          return [x]*n

      def longest(x: A, y: A) -> A:
          '''Return the longest of two strings.'''
          return x if len(x) >= len(y) else y

    The latter example's signature is essentially the overloading
    of (str, str) -> str and (bytes, bytes) -> bytes.  Also note
    that if the arguments are instances of some subclass of str,
    the return type is still plain str.

    At runtime, isinstance(x, T) and issubclass(C, T) will raise TypeError.

    Type variables defined with covariant=True or contravariant=True
    can be used to declare covariant or contravariant generic types.
    See PEP 484 for more details. By default generic types are invariant
    in all type variables.

    Type variables can be introspected. e.g.:

      T.__name__ == 'T'
      T.__constraints__ == ()
      T.__covariant__ == False
      T.__contravariant__ = False
      A.__constraints__ == (str, bytes)

    Note that only type variables defined in global scope can be pickled.
    

Constructeur(s)

Signature du constructeur	Description
__init__(self, name, *constraints, bound=None, covariant=False, contravariant=False)

Liste des opérateurs

Opérateurs hérités de la classe _BoundVarianceMixin

__or__, __ror__

Liste des opérateurs

Opérateurs hérités de la classe object

__eq__, __ge__, __gt__, __le__, __lt__, __ne__

Méthodes héritées de la classe _PickleUsingNameMixin

__init_subclass__, __reduce__, __subclasshook__

Méthodes héritées de la classe _BoundVarianceMixin

__init_subclass__, __repr__, __subclasshook__

Méthodes héritées de la classe _Immutable

__copy__, __deepcopy__, __init_subclass__, __subclasshook__

Méthodes héritées de la classe _Final

__init_subclass__, __subclasshook__

Méthodes héritées de la classe object

__delattr__, __dir__, __format__, __getattribute__, __getstate__, __hash__, __init_subclass__, __reduce__, __reduce_ex__, __repr__, __setattr__, __sizeof__, __str__, __subclasshook__