graphene/docs/types/enums.rst
2016-10-07 12:23:12 +02:00

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Enums
=====
A ``Enum`` is a special ``GraphQL`` type that represents a set of
symbolic names (members) bound to unique, constant values.
Definition
----------
You can create an ``Enum`` using classes:
.. code:: python
import graphene
class Episode(graphene.Enum):
NEWHOPE = 4
EMPIRE = 5
JEDI = 6
But also using instances of Enum:
.. code:: python
Episode = graphene.Enum('Episode', [('NEWHOPE', 4), ('EMPIRE', 5), ('JEDI', 6)])
Value descriptions
------------------
It's possible to add a description to a enum value, for that the the enum value
needs to have the ``description`` property on it.
.. code:: python
class Episode(graphene.Enum):
NEWHOPE = 4
EMPIRE = 5
JEDI = 6
@property
def description(self):
if self == Episode.NEWHOPE:
return 'New Hope Episode'
return 'Other episode'
Usage with Python Enums
-----------------------
In case the Enums are already defined it's possible to reuse them using
the ``Enum.from_enum`` function.
.. code:: python
graphene.Enum.from_enum(AlreadyExistingPyEnum)
Notes
-----
``graphene.Enum`` uses |enum.Enum|_ internally (or a backport if
that's not available) and can be used in the exact same way.
.. |enum.Enum| replace:: ``enum.Enum``
.. _enum.Enum: https://docs.python.org/3/library/enum.html