Enums and Choices

Pydantic uses Python's standard enum classes to define choices.

enum.Enum: checks that the value is a valid Enum instance.
subclass of enum.Enum: checks that the value is a valid member of the enum.
enum.IntEnum: checks that the value is a valid IntEnum instance.
subclass of enum.IntEnum: checks that the value is a valid member of the integer enum.

from enum import Enum, IntEnum

from pydantic import BaseModel, ValidationError


class FruitEnum(str, Enum):
    pear = 'pear'
    banana = 'banana'


class ToolEnum(IntEnum):
    spanner = 1
    wrench = 2


class CookingModel(BaseModel):
    fruit: FruitEnum = FruitEnum.pear
    tool: ToolEnum = ToolEnum.spanner


print(CookingModel())
#> fruit=<FruitEnum.pear: 'pear'> tool=<ToolEnum.spanner: 1>
print(CookingModel(tool=2, fruit='banana'))
#> fruit=<FruitEnum.banana: 'banana'> tool=<ToolEnum.wrench: 2>
try:
    CookingModel(fruit='other')
except ValidationError as e:
    print(e)
    """
    1 validation error for CookingModel
    fruit
      Input should be 'pear' or 'banana' [type=enum, input_value='other', input_type=str]
    """