enum — Support for enumerations¶

모듈 내용¶

EnumType

The type for Enum and its subclasses.

Enum

열거형 상수를 만들기 위한 베이스 클래스.

IntEnum

int의 서브 클래스이기도 한 열거형 상수를 만들기 위한 베이스 클래스. (Notes)

StrEnum

str의 서브 클래스이기도 한 열거형 상수를 만들기 위한 베이스 클래스. (Notes)

Flag

Flag 멤버십을 잃지 않고 비트 연산을 사용하여 결합할 수 있는 열거형 상수를 만들기 위한 베이스 클래스.

IntFlag

IntFlag 멤버십을 잃지 않고 비트 연산자를 사용하여 결합할 수 있는 열거형 상수를 만들기 위한 베이스 클래스. IntFlag 멤버도 int의 서브 클래스입니다. (Notes)

ReprEnum

Used by IntEnum, StrEnum, and IntFlag to keep the str() of the mixed-in type.

EnumCheck

An enumeration with the values CONTINUOUS, NAMED_FLAGS, and UNIQUE, for use with verify() to ensure various constraints are met by a given enumeration.

FlagBoundary

An enumeration with the values STRICT, CONFORM, EJECT, and KEEP which allows for more fine-grained control over how invalid values are dealt with in an enumeration.

auto

Instances are replaced with an appropriate value for Enum members. StrEnum defaults to the lower-cased version of the member name, while other Enums default to 1 and increase from there.

property()

Allows Enum members to have attributes without conflicting with member names.

unique()

한 값에 하나의 이름 만 연결되도록 하는 Enum 클래스 데코레이터.

verify()

Enum class decorator that checks user-selectable constraints on an enumeration.

member()

Make obj a member. Can be used as a decorator.

nonmember()

Do not make obj a member. Can be used as a decorator.

global_enum()

Modify the str() and repr() of an enum to show its members as belonging to the module instead of its class, and export the enum members to the global namespace.

show_flag_values()

Return a list of all power-of-two integers contained in a flag.

Data Types¶

class enum.EnumType¶

EnumType is the metaclass for enum enumerations. It is possible to subclass EnumType – see Subclassing EnumType for details.

EnumType is responsible for setting the correct __repr__(), __str__(), __format__(), and __reduce__() methods on the final enum, as well as creating the enum members, properly handling duplicates, providing iteration over the enum class, etc.

__call__(cls, value, names=None, *, module=None, qualname=None, type=None, start=1, boundary=None)¶

This method is called in two different ways:

• to look up an existing member:

  cls:

  The enum class being called.

  value:

  The value to lookup.

• to use the cls enum to create a new enum (only if the existing enum does not have any members):

  cls:

  The enum class being called.

  value:

  The name of the new Enum to create.

  names:

  The names/values of the members for the new Enum.

  module:

  새로운 Enum 이 만들어지는 모듈의 이름.

  qualname:

  이 Enum 이 모듈에서 실제로 위치한 곳.

  type:

  A mix-in type for the new Enum.

  start:

  The first integer value for the Enum (used by auto).

  boundary:

  How to handle out-of-range values from bit operations (Flag only).

__contains__(cls, member)¶

Returns True if member belongs to the cls:

>>> some_var = Color.RED
>>> some_var in Color
True

참고

In Python 3.12 it will be possible to check for member values and not just members; until then, a TypeError will be raised if a non-Enum-member is used in a containment check.

__dir__(cls)¶

Returns ['__class__', '__doc__', '__members__', '__module__'] and the names of the members in cls:

>>> dir(Color)
['BLUE', 'GREEN', 'RED', '__class__', '__contains__', '__doc__', '__getitem__', '__init_subclass__', '__iter__', '__len__', '__members__', '__module__', '__name__', '__qualname__']

__getattr__(cls, name)¶

Returns the Enum member in cls matching name, or raises an AttributeError:

>>> Color.GREEN
<Color.GREEN: 2>

__getitem__(cls, name)¶

Returns the Enum member in cls matching name, or raises a KeyError:

>>> Color['BLUE']
<Color.BLUE: 3>

__iter__(cls)¶

cls 의 각 멤버를 정의 순서로 반환합니다:

>>> list(Color)
[<Color.RED: 1>, <Color.GREEN: 2>, <Color.BLUE: 3>]

__len__(cls)¶

Returns the number of member in cls:

>>> len(Color)
3

__reversed__(cls)¶

Returns each member in cls in reverse definition order:

>>> list(reversed(Color))
[<Color.BLUE: 3>, <Color.GREEN: 2>, <Color.RED: 1>]

버전 3.11에 추가: Before 3.11 enum used EnumMeta type, which is kept as an alias.

class enum.Enum¶

Enum is the base class for all enum enumerations.

name¶

The name used to define the Enum member:

>>> Color.BLUE.name
'BLUE'

value¶

The value given to the Enum member:

>>> Color.RED.value
1

Value of the member, can be set in __new__().

참고

Enum 멤버 값

멤버 값은 아무것이나 될 수 있습니다: int, str 등. 정확한 값이 중요하지 않다면, auto 인스턴스를 사용할 수 있으며 적절한 값이 선택됩니다. 자세한 내용은 auto를 참조하세요.

While mutable/unhashable values, such as dict, list or a mutable dataclass, can be used, they will have a quadratic performance impact during creation relative to the total number of mutable/unhashable values in the enum.

_name_¶

멤버의 이름.

_value_¶

Value of the member, can be set in __new__().

_order_¶

더는 사용되지 않습니다, 하위 호환성을 위해 유지됩니다. (클래스 생성 중 제거되는 클래스 어트리뷰트)

_ignore_¶

_ignore_ is only used during creation and is removed from the enumeration once creation is complete.

_ignore_ is a list of names that will not become members, and whose names will also be removed from the completed enumeration. See TimePeriod for an example.

__dir__(self)¶

Returns ['__class__', '__doc__', '__module__', 'name', 'value'] and any public methods defined on self.__class__:

>>> from datetime import date
>>> class Weekday(Enum):
...     MONDAY = 1
...     TUESDAY = 2
...     WEDNESDAY = 3
...     THURSDAY = 4
...     FRIDAY = 5
...     SATURDAY = 6
...     SUNDAY = 7
...     @classmethod
...     def today(cls):
...         print('today is %s' % cls(date.today().isoweekday()).name)
>>> dir(Weekday.SATURDAY)
['__class__', '__doc__', '__eq__', '__hash__', '__module__', 'name', 'today', 'value']

_generate_next_value_(name, start, count, last_values)¶

name:

The name of the member being defined (e.g. ‘RED’).

start:

The start value for the Enum; the default is 1.

count:

The number of members currently defined, not including this one.

last_values:

A list of the previous values.

A staticmethod that is used to determine the next value returned by auto:

>>> from enum import auto
>>> class PowersOfThree(Enum):
...     @staticmethod
...     def _generate_next_value_(name, start, count, last_values):
...         return 3 ** (count + 1)
...     FIRST = auto()
...     SECOND = auto()
>>> PowersOfThree.SECOND.value
9

__init_subclass__(cls, **kwds)¶

A classmethod that is used to further configure subsequent subclasses. By default, does nothing.

_missing_(cls, value)¶

A classmethod for looking up values not found in cls. By default it does nothing, but can be overridden to implement custom search behavior:

>>> from enum import StrEnum
>>> class Build(StrEnum):
...     DEBUG = auto()
...     OPTIMIZED = auto()
...     @classmethod
...     def _missing_(cls, value):
...         value = value.lower()
...         for member in cls:
...             if member.value == value:
...                 return member
...         return None
>>> Build.DEBUG.value
'debug'
>>> Build('deBUG')
<Build.DEBUG: 'debug'>

__repr__(self)¶

Returns the string used for repr() calls. By default, returns the Enum name, member name, and value, but can be overridden:

>>> class OtherStyle(Enum):
...     ALTERNATE = auto()
...     OTHER = auto()
...     SOMETHING_ELSE = auto()
...     def __repr__(self):
...         cls_name = self.__class__.__name__
...         return f'{cls_name}.{self.name}'
>>> OtherStyle.ALTERNATE, str(OtherStyle.ALTERNATE), f"{OtherStyle.ALTERNATE}"
(OtherStyle.ALTERNATE, 'OtherStyle.ALTERNATE', 'OtherStyle.ALTERNATE')

__str__(self)¶

Returns the string used for str() calls. By default, returns the Enum name and member name, but can be overridden:

>>> class OtherStyle(Enum):
...     ALTERNATE = auto()
...     OTHER = auto()
...     SOMETHING_ELSE = auto()
...     def __str__(self):
...         return f'{self.name}'
>>> OtherStyle.ALTERNATE, str(OtherStyle.ALTERNATE), f"{OtherStyle.ALTERNATE}"
(<OtherStyle.ALTERNATE: 1>, 'ALTERNATE', 'ALTERNATE')

__format__(self)¶

Returns the string used for format() and f-string calls. By default, returns __str__() return value, but can be overridden:

>>> class OtherStyle(Enum):
...     ALTERNATE = auto()
...     OTHER = auto()
...     SOMETHING_ELSE = auto()
...     def __format__(self, spec):
...         return f'{self.name}'
>>> OtherStyle.ALTERNATE, str(OtherStyle.ALTERNATE), f"{OtherStyle.ALTERNATE}"
(<OtherStyle.ALTERNATE: 1>, 'OtherStyle.ALTERNATE', 'ALTERNATE')

참고

Using auto with Enum results in integers of increasing value, starting with 1.

class enum.IntEnum¶

IntEnum is the same as Enum, but its members are also integers and can be used anywhere that an integer can be used. If any integer operation is performed with an IntEnum member, the resulting value loses its enumeration status.

>>> from enum import IntEnum
>>> class Number(IntEnum):
...     ONE = 1
...     TWO = 2
...     THREE = 3
...
>>> Number.THREE
<Number.THREE: 3>
>>> Number.ONE + Number.TWO
3
>>> Number.THREE + 5
8
>>> Number.THREE == 3
True

참고

Using auto with IntEnum results in integers of increasing value, starting with 1.

버전 3.11에서 변경: __str__() is now int.__str__() to better support the replacement of existing constants use-case. __format__() was already int.__format__() for that same reason.

class enum.StrEnum¶

StrEnum is the same as Enum, but its members are also strings and can be used in most of the same places that a string can be used. The result of any string operation performed on or with a StrEnum member is not part of the enumeration.

참고

There are places in the stdlib that check for an exact str instead of a str subclass (i.e. type(unknown) == str instead of isinstance(unknown, str)), and in those locations you will need to use str(StrEnum.member).

참고

Using auto with StrEnum results in the lower-cased member name as the value.

참고

__str__() is str.__str__() to better support the replacement of existing constants use-case. __format__() is likewise str.__format__() for that same reason.

버전 3.11에 추가.

class enum.Flag¶

Flag members support the bitwise operators & (AND), | (OR), ^ (XOR), and ~ (INVERT); the results of those operators are members of the enumeration.

__contains__(self, value)¶

Returns True if value is in self:

>>> from enum import Flag, auto
>>> class Color(Flag):
...     RED = auto()
...     GREEN = auto()
...     BLUE = auto()
>>> purple = Color.RED | Color.BLUE
>>> white = Color.RED | Color.GREEN | Color.BLUE
>>> Color.GREEN in purple
False
>>> Color.GREEN in white
True
>>> purple in white
True
>>> white in purple
False

__iter__(self):

Returns all contained non-alias members:

>>> list(Color.RED)
[<Color.RED: 1>]
>>> list(purple)
[<Color.RED: 1>, <Color.BLUE: 4>]

버전 3.11에 추가.

__len__(self):

Returns number of members in flag:

>>> len(Color.GREEN)
1
>>> len(white)
3

__bool__(self):

Returns True if any members in flag, False otherwise:

>>> bool(Color.GREEN)
True
>>> bool(white)
True
>>> black = Color(0)
>>> bool(black)
False

__or__(self, other)¶

Returns current flag binary or’ed with other:

>>> Color.RED | Color.GREEN
<Color.RED|GREEN: 3>

__and__(self, other)¶

Returns current flag binary and’ed with other:

>>> purple & white
<Color.RED|BLUE: 5>
>>> purple & Color.GREEN
<Color: 0>

__xor__(self, other)¶

Returns current flag binary xor’ed with other:

>>> purple ^ white
<Color.GREEN: 2>
>>> purple ^ Color.GREEN
<Color.RED|GREEN|BLUE: 7>

__invert__(self):

Returns all the flags in type(self) that are not in self:

>>> ~white
<Color: 0>
>>> ~purple
<Color.GREEN: 2>
>>> ~Color.RED
<Color.GREEN|BLUE: 6>

_numeric_repr_()¶

Function used to format any remaining unnamed numeric values. Default is the value’s repr; common choices are hex() and oct().

참고

Using auto with Flag results in integers that are powers of two, starting with 1.

버전 3.11에서 변경: The repr() of zero-valued flags has changed. It is now::

>>> Color(0) 
<Color: 0>

class enum.IntFlag¶

IntFlag is the same as Flag, but its members are also integers and can be used anywhere that an integer can be used.

>>> from enum import IntFlag, auto
>>> class Color(IntFlag):
...     RED = auto()
...     GREEN = auto()
...     BLUE = auto()
>>> Color.RED & 2
<Color: 0>
>>> Color.RED | 2
<Color.RED|GREEN: 3>

If any integer operation is performed with an IntFlag member, the result is not an IntFlag:

>>> Color.RED + 2
3

If a Flag operation is performed with an IntFlag member and:

• the result is a valid IntFlag: an IntFlag is returned

• the result is not a valid IntFlag: the result depends on the FlagBoundary setting

The repr() of unnamed zero-valued flags has changed. It is now:

>>> Color(0)
<Color: 0>

참고

Using auto with IntFlag results in integers that are powers of two, starting with 1.

버전 3.11에서 변경: __str__() is now int.__str__() to better support the replacement of existing constants use-case. __format__() was already int.__format__() for that same reason.

Inversion of an IntFlag now returns a positive value that is the union of all flags not in the given flag, rather than a negative value. This matches the existing Flag behavior.

class enum.ReprEnum¶

ReprEnum uses the repr() of Enum, but the str() of the mixed-in data type:

• int.__str__() for IntEnum and IntFlag

• str.__str__() for StrEnum

Inherit from ReprEnum to keep the str() / format() of the mixed-in data type instead of using the Enum-default str().

버전 3.11에 추가.

class enum.EnumCheck¶

EnumCheck contains the options used by the verify() decorator to ensure various constraints; failed constraints result in a ValueError.

UNIQUE¶

Ensure that each value has only one name:

>>> from enum import Enum, verify, UNIQUE
>>> @verify(UNIQUE)
... class Color(Enum):
...     RED = 1
...     GREEN = 2
...     BLUE = 3
...     CRIMSON = 1
Traceback (most recent call last):
...
ValueError: aliases found in <enum 'Color'>: CRIMSON -> RED

CONTINUOUS¶

Ensure that there are no missing values between the lowest-valued member and the highest-valued member:

>>> from enum import Enum, verify, CONTINUOUS
>>> @verify(CONTINUOUS)
... class Color(Enum):
...     RED = 1
...     GREEN = 2
...     BLUE = 5
Traceback (most recent call last):
...
ValueError: invalid enum 'Color': missing values 3, 4

NAMED_FLAGS¶

Ensure that any flag groups/masks contain only named flags – useful when values are specified instead of being generated by auto():

>>> from enum import Flag, verify, NAMED_FLAGS
>>> @verify(NAMED_FLAGS)
... class Color(Flag):
...     RED = 1
...     GREEN = 2
...     BLUE = 4
...     WHITE = 15
...     NEON = 31
Traceback (most recent call last):
...
ValueError: invalid Flag 'Color': aliases WHITE and NEON are missing combined values of 0x18 [use enum.show_flag_values(value) for details]

참고

CONTINUOUS and NAMED_FLAGS are designed to work with integer-valued members.

버전 3.11에 추가.

class enum.FlagBoundary¶

FlagBoundary controls how out-of-range values are handled in Flag and its subclasses.

STRICT¶

Out-of-range values cause a ValueError to be raised. This is the default for Flag:

>>> from enum import Flag, STRICT, auto
>>> class StrictFlag(Flag, boundary=STRICT):
...     RED = auto()
...     GREEN = auto()
...     BLUE = auto()
>>> StrictFlag(2**2 + 2**4)
Traceback (most recent call last):
...
ValueError: <flag 'StrictFlag'> invalid value 20
    given 0b0 10100
  allowed 0b0 00111

CONFORM¶

Out-of-range values have invalid values removed, leaving a valid Flag value:

>>> from enum import Flag, CONFORM, auto
>>> class ConformFlag(Flag, boundary=CONFORM):
...     RED = auto()
...     GREEN = auto()
...     BLUE = auto()
>>> ConformFlag(2**2 + 2**4)
<ConformFlag.BLUE: 4>

EJECT¶

Out-of-range values lose their Flag membership and revert to int.

>>> from enum import Flag, EJECT, auto
>>> class EjectFlag(Flag, boundary=EJECT):
...     RED = auto()
...     GREEN = auto()
...     BLUE = auto()
>>> EjectFlag(2**2 + 2**4)
20

KEEP¶

Out-of-range values are kept, and the Flag membership is kept. This is the default for IntFlag:

>>> from enum import Flag, KEEP, auto
>>> class KeepFlag(Flag, boundary=KEEP):
...     RED = auto()
...     GREEN = auto()
...     BLUE = auto()
>>> KeepFlag(2**2 + 2**4)
<KeepFlag.BLUE|16: 20>

Utilities and Decorators¶

class enum.auto¶

auto can be used in place of a value. If used, the Enum machinery will call an Enum’s _generate_next_value_() to get an appropriate value. For Enum and IntEnum that appropriate value will be the last value plus one; for Flag and IntFlag it will be the first power-of-two greater than the highest value; for StrEnum it will be the lower-cased version of the member’s name. Care must be taken if mixing auto() with manually specified values.

auto instances are only resolved when at the top level of an assignment:

• FIRST = auto() will work (auto() is replaced with 1);

• SECOND = auto(), -2 will work (auto is replaced with 2, so 2, -2 is used to create the SECOND enum member;

• THREE = [auto(), -3] will not work (<auto instance>, -3 is used to create the THREE enum member)

버전 3.11.1에서 변경: In prior versions, auto() had to be the only thing on the assignment line to work properly.

_generate_next_value_ can be overridden to customize the values used by auto.

참고

in 3.13 the default _generate_next_value_ will always return the highest member value incremented by 1, and will fail if any member is an incompatible type.

@enum.property¶

A decorator similar to the built-in property, but specifically for enumerations. It allows member attributes to have the same names as members themselves.

참고

the property and the member must be defined in separate classes; for example, the value and name attributes are defined in the Enum class, and Enum subclasses can define members with the names value and name.

버전 3.11에 추가.

@enum.unique¶

열거형 용 class 데코레이터입니다. 열거형의 __members__를 검색하여, 별칭을 수집합니다; 발견되면 ValueError가 세부 정보와 함께 발생합니다:

>>> from enum import Enum, unique
>>> @unique
... class Mistake(Enum):
...     ONE = 1
...     TWO = 2
...     THREE = 3
...     FOUR = 3
...
Traceback (most recent call last):
...
ValueError: duplicate values found in <enum 'Mistake'>: FOUR -> THREE

@enum.verify¶

A class decorator specifically for enumerations. Members from EnumCheck are used to specify which constraints should be checked on the decorated enumeration.

버전 3.11에 추가.

@enum.member¶

A decorator for use in enums: its target will become a member.

버전 3.11에 추가.

@enum.nonmember¶

A decorator for use in enums: its target will not become a member.

버전 3.11에 추가.

@enum.global_enum¶

A decorator to change the str() and repr() of an enum to show its members as belonging to the module instead of its class. Should only be used when the enum members are exported to the module global namespace (see re.RegexFlag for an example).

버전 3.11에 추가.

enum.show_flag_values(value)¶

Return a list of all power-of-two integers contained in a flag value.

버전 3.11에 추가.

참고 사항¶

IntEnum, StrEnum, 및 IntFlag

These three enum types are designed to be drop-in replacements for existing integer- and string-based values; as such, they have extra limitations:

• __str__ uses the value and not the name of the enum member

• __format__, because it uses __str__, will also use the value of the enum member instead of its name

If you do not need/want those limitations, you can either create your own base class by mixing in the int or str type yourself:

>>> from enum import Enum
>>> class MyIntEnum(int, Enum):
...     pass

or you can reassign the appropriate str(), etc., in your enum:

>>> from enum import Enum, IntEnum
>>> class MyIntEnum(IntEnum):
...     __str__ = Enum.__str__