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RootModel

RootModel class and type definitions.

RootModel

RootModel(
    root: RootModelRootType = PydanticUndefined, **data
)

Bases: BaseModel, Generic[RootModelRootType]

Usage Documentation

RootModel and custom root types

A Pydantic BaseModel for the root object of the model.

Attributes:

Name Type Description
root RootModelRootType

The root object of the model.

__pydantic_root_model__

Whether the model is a RootModel.

__pydantic_private__

Private fields in the model.

__pydantic_extra__

Extra fields in the model.

Source code in pydantic/root_model.py
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def __init__(self, /, root: RootModelRootType = PydanticUndefined, **data) -> None:  # type: ignore
    __tracebackhide__ = True
    if data:
        if root is not PydanticUndefined:
            raise ValueError(
                '"RootModel.__init__" accepts either a single positional argument or arbitrary keyword arguments'
            )
        root = data  # type: ignore
    self.__pydantic_validator__.validate_python(root, self_instance=self)

model_construct classmethod

model_construct(
    root: RootModelRootType,
    _fields_set: set[str] | None = None,
) -> Model

Create a new model using the provided root object and update fields set.

Parameters:

Name Type Description Default
root RootModelRootType

The root object of the model.

required
_fields_set set[str] | None

The set of fields to be updated.

None

Returns:

Type Description
Model

The new model.

Raises:

Type Description
NotImplemented

If the model is not a subclass of RootModel.

Source code in pydantic/root_model.py
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@classmethod
def model_construct(cls: type[Model], root: RootModelRootType, _fields_set: set[str] | None = None) -> Model:  # type: ignore
    """Create a new model using the provided root object and update fields set.

    Args:
        root: The root object of the model.
        _fields_set: The set of fields to be updated.

    Returns:
        The new model.

    Raises:
        NotImplemented: If the model is not a subclass of `RootModel`.
    """
    return super().model_construct(root=root, _fields_set=_fields_set)

model_dump

model_dump(
    *,
    mode: Literal["json", "python"] | str = "python",
    include: Any = None,
    exclude: Any = None,
    by_alias: bool = False,
    exclude_unset: bool = False,
    exclude_defaults: bool = False,
    exclude_none: bool = False,
    round_trip: bool = False,
    warnings: bool = True
) -> Any

This method is included just to get a more accurate return type for type checkers. It is included in this if TYPE_CHECKING: block since no override is actually necessary.

See the documentation of BaseModel.model_dump for more details about the arguments.

Generally, this method will have a return type of RootModelRootType, assuming that RootModelRootType is not a BaseModel subclass. If RootModelRootType is a BaseModel subclass, then the return type will likely be dict[str, Any], as model_dump calls are recursive. The return type could even be something different, in the case of a custom serializer. Thus, Any is used here to catch all of these cases.

Source code in pydantic/root_model.py
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def model_dump(  # type: ignore
    self,
    *,
    mode: Literal['json', 'python'] | str = 'python',
    include: Any = None,
    exclude: Any = None,
    by_alias: bool = False,
    exclude_unset: bool = False,
    exclude_defaults: bool = False,
    exclude_none: bool = False,
    round_trip: bool = False,
    warnings: bool = True,
) -> Any:
    """This method is included just to get a more accurate return type for type checkers.
    It is included in this `if TYPE_CHECKING:` block since no override is actually necessary.

    See the documentation of `BaseModel.model_dump` for more details about the arguments.

    Generally, this method will have a return type of `RootModelRootType`, assuming that `RootModelRootType` is
    not a `BaseModel` subclass. If `RootModelRootType` is a `BaseModel` subclass, then the return
    type will likely be `dict[str, Any]`, as `model_dump` calls are recursive. The return type could
    even be something different, in the case of a custom serializer.
    Thus, `Any` is used here to catch all of these cases.
    """
    ...