CODEWITHSUNDEEP
python
jia Jimmy
jia Jimmy

Reputation: 1848

How to abstract a base class with a specified method?

Say all subclass can get its own choice like class.choice()

from enum import IntEnum

class CompanyType(IntEnum):
    BySelf = 1
    Agency = 2

    @staticmethod
    def choice():
        return  [
        (i.value, i.name) for i in CompanyType
    ]


class CompanyStatus(IntEnum):
    StartUp = 1
    LargeCompany = 2

    @staticmethod
    def choice():
        return [
            (i.value, i.name) for i in CompanyStatus
        ]
...

How can I abstract a base class that can be inherited with method choice

Expected as:

from enum import IntEnum

class ChoiceBase_():

    @staticmethod
    def choice():
        return [
            (i.value, i.name) for i in specified_subclass
        ]


class CompanyType(ChoiceBase_, IntEnum):
    BySelf = 1
    Agency = 2


class CompanyStatus(ChoiceBase_, IntEnum):
    StartUp = 1
    LargeCompany = 2


print(CompanyType.choice())
print(CompanyStatus.choice())

Upvotes: 0

Views: 48

Answers (1)

Maurice Meyer
Maurice Meyer

Reputation: 18106

Use the classmethod decorator in order to get the classes constants:

class ChoiceBase_():
    @classmethod
    def choice(cls):
        return [(i.value, i.name) for i in cls]


class CompanyType(ChoiceBase_, IntEnum):
    BySelf = 1
    Agency = 2


class CompanyStatus(ChoiceBase_, IntEnum):
    StartUp = 1
    LargeCompany = 2


print(CompanyType.choice())
print(CompanyStatus.choice())

Out:

[(1, 'BySelf'), (2, 'Agency')]
[(1, 'StartUp'), (2, 'LargeCompany')]

Edit:

In Python36, inheriting from int makes sure to use use int.__new__() as stated in the error message:

from enum import Enum
class CompanyStatus(int, ChoiceBase_, Enum):
    StartUp = 1
    LargeCompany = 2

Upvotes: 4

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