diff --git a/Doc/library/enum.rst b/Doc/library/enum.rst index a76f5a369ca..377ac3e2450 100644 --- a/Doc/library/enum.rst +++ b/Doc/library/enum.rst @@ -257,7 +257,7 @@ members are not integers (but see `IntEnum`_ below):: >>> Color.red < Color.blue Traceback (most recent call last): File "", line 1, in - TypeError: '<' not supported between instances of 'Color' and 'Color' + TypeError: unorderable types: Color() < Color() Equality comparisons are defined though:: @@ -747,6 +747,15 @@ besides the :class:`Enum` member you looking for:: .. versionchanged:: 3.5 +Boolean evaluation: Enum classes that are mixed with non-Enum types (such as +:class:`int`, :class:`str`, etc.) are evaluated according to the mixed-in +type's rules; otherwise, all members evaluate as ``True``. To make your own +Enum's boolean evaluation depend on the member's value add the following to +your class:: + + def __bool__(self): + return bool(self._value_) + The :attr:`__members__` attribute is only available on the class. If you give your :class:`Enum` subclass extra methods, like the `Planet`_ diff --git a/Lib/enum.py b/Lib/enum.py index 35a9c779356..ac89d6ba26e 100644 --- a/Lib/enum.py +++ b/Lib/enum.py @@ -482,9 +482,6 @@ class Enum(metaclass=EnumMeta): def __str__(self): return "%s.%s" % (self.__class__.__name__, self._name_) - def __bool__(self): - return bool(self._value_) - def __dir__(self): added_behavior = [ m diff --git a/Lib/test/test_enum.py b/Lib/test/test_enum.py index e4e6c2b51af..7985948041a 100644 --- a/Lib/test/test_enum.py +++ b/Lib/test/test_enum.py @@ -272,11 +272,26 @@ class TestEnum(unittest.TestCase): _any_name_ = 9 def test_bool(self): + # plain Enum members are always True class Logic(Enum): true = True false = False self.assertTrue(Logic.true) - self.assertFalse(Logic.false) + self.assertTrue(Logic.false) + # unless overridden + class RealLogic(Enum): + true = True + false = False + def __bool__(self): + return bool(self._value_) + self.assertTrue(RealLogic.true) + self.assertFalse(RealLogic.false) + # mixed Enums depend on mixed-in type + class IntLogic(int, Enum): + true = 1 + false = 0 + self.assertTrue(IntLogic.true) + self.assertFalse(IntLogic.false) def test_contains(self): Season = self.Season