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BaseModel

BaseModel

A base class for creating Pydantic models.

Attributes

model_config

Configuration for the model, should be a dictionary conforming to ConfigDict.

Type: ConfigDict Default: ConfigDict()

pydantic_core_schema

The core schema of the model.

Type: CoreSchema

model_extra

Get extra fields set during validation.

Type: dict[str, Any] | None

model_fields_set

Returns the set of fields that have been explicitly set on this model instance.

Type: set[str]

Methods

init

def __init__(data: Any = {}) -> None

Create a new model by parsing and validating input data from keyword arguments.

Raises ValidationError if the input data cannot be validated to form a valid model.

self is explicitly positional-only to allow self as a field name.

Returns

None

model_fields

@classmethod

def model_fields(cls) -> dict[str, FieldInfo]

A mapping of field names to their respective FieldInfo instances.

Returns

dict[str, FieldInfo]

model_computed_fields

@classmethod

def model_computed_fields(cls) -> dict[str, ComputedFieldInfo]

A mapping of computed field names to their respective ComputedFieldInfo instances.

Returns

dict[str, ComputedFieldInfo]

model_construct

@classmethod

def model_construct(cls, _fields_set: set[str] | None = None, values: Any = {}) -> Self

Creates a new instance of the Model class with validated data.

Creates a new model setting __dict__ and __pydantic_fields_set__ from trusted or pre-validated data. Default values are respected, but no other validation is performed.

Returns

Self — A new instance of the Model class with validated data.

Parameters

_fields_set : set[str] | None Default: None

A set of field names that were originally explicitly set during instantiation. If provided, this is directly used for the model_fields_set attribute. Otherwise, the field names from the values argument will be used.

values : Any Default: \{\}

Trusted or pre-validated data dictionary.

model_copy

def model_copy(update: Mapping[str, Any] | None = None, deep: bool = False) -> Self

Returns a copy of the model.

Returns

Self — New model instance.

Parameters

update : Mapping[str, Any] | None Default: None

Values to change/add in the new model. Note: the data is not validated before creating the new model. You should trust this data.

deep : bool Default: False

Set to True to make a deep copy of the model.

model_dump

def model_dump(
    mode: Literal['json', 'python'] | str = 'python',
    include: IncEx | None = None,
    exclude: IncEx | None = None,
    context: Any | None = None,
    by_alias: bool | None = None,
    exclude_unset: bool = False,
    exclude_defaults: bool = False,
    exclude_none: bool = False,
    round_trip: bool = False,
    warnings: bool | Literal['none', 'warn', 'error'] = True,
    fallback: Callable[[Any], Any] | None = None,
    serialize_as_any: bool = False,
) -> dict[str, Any]

Generate a dictionary representation of the model, optionally specifying which fields to include or exclude.

Returns

dict[str, Any] — A dictionary representation of the model.

Parameters

mode : Literal['json', 'python'] | str Default: 'python'

The mode in which to_python should run. If mode is ‘json’, the output will only contain JSON serializable types. If mode is ‘python’, the output may contain non-JSON-serializable Python objects.

include : IncEx | None Default: None

A set of fields to include in the output.

exclude : IncEx | None Default: None

A set of fields to exclude from the output.

context : Any | None Default: None

Additional context to pass to the serializer.

by_alias : bool | None Default: None

Whether to use the field’s alias in the dictionary key if defined.

exclude_unset : bool Default: False

Whether to exclude fields that have not been explicitly set.

exclude_defaults : bool Default: False

Whether to exclude fields that are set to their default value.

exclude_none : bool Default: False

Whether to exclude fields that have a value of None.

round_trip : bool Default: False

If True, dumped values should be valid as input for non-idempotent types such as Json[T].

warnings : bool | Literal['none', 'warn', 'error'] Default: True

How to handle serialization errors. False/“none” ignores them, True/“warn” logs errors, “error” raises a PydanticSerializationError.

fallback : Callable[[Any], Any] | None Default: None

A function to call when an unknown value is encountered. If not provided, a PydanticSerializationError error is raised.

serialize_as_any : bool Default: False

Whether to serialize fields with duck-typing serialization behavior.

model_dump_json

def model_dump_json(
    indent: int | None = None,
    include: IncEx | None = None,
    exclude: IncEx | None = None,
    context: Any | None = None,
    by_alias: bool | None = None,
    exclude_unset: bool = False,
    exclude_defaults: bool = False,
    exclude_none: bool = False,
    round_trip: bool = False,
    warnings: bool | Literal['none', 'warn', 'error'] = True,
    fallback: Callable[[Any], Any] | None = None,
    serialize_as_any: bool = False,
) -> str

Generates a JSON representation of the model using Pydantic’s to_json method.

Returns

str — A JSON string representation of the model.

Parameters

indent : int | None Default: None

Indentation to use in the JSON output. If None is passed, the output will be compact.

include : IncEx | None Default: None

Field(s) to include in the JSON output.

exclude : IncEx | None Default: None

Field(s) to exclude from the JSON output.

context : Any | None Default: None

Additional context to pass to the serializer.

by_alias : bool | None Default: None

Whether to serialize using field aliases.

exclude_unset : bool Default: False

Whether to exclude fields that have not been explicitly set.

exclude_defaults : bool Default: False

Whether to exclude fields that are set to their default value.

exclude_none : bool Default: False

Whether to exclude fields that have a value of None.

round_trip : bool Default: False

If True, dumped values should be valid as input for non-idempotent types such as Json[T].

warnings : bool | Literal['none', 'warn', 'error'] Default: True

How to handle serialization errors. False/“none” ignores them, True/“warn” logs errors, “error” raises a PydanticSerializationError.

fallback : Callable[[Any], Any] | None Default: None

A function to call when an unknown value is encountered. If not provided, a PydanticSerializationError error is raised.

serialize_as_any : bool Default: False

Whether to serialize fields with duck-typing serialization behavior.

model_json_schema

@classmethod

def model_json_schema(
    cls,
    by_alias: bool = True,
    ref_template: str = DEFAULT_REF_TEMPLATE,
    schema_generator: type[GenerateJsonSchema] = GenerateJsonSchema,
    mode: JsonSchemaMode = 'validation',
) -> dict[str, Any]

Generates a JSON schema for a model class.

Returns

dict[str, Any] — The JSON schema for the given model class.

Parameters

by_alias : bool Default: True

Whether to use attribute aliases or not.

ref_template : str Default: DEFAULT_REF_TEMPLATE

The reference template.

schema_generator : type[GenerateJsonSchema] Default: GenerateJsonSchema

To override the logic used to generate the JSON schema, as a subclass of GenerateJsonSchema with your desired modifications

mode : JsonSchemaMode Default: 'validation'

The mode in which to generate the schema.

model_parametrized_name

@classmethod

def model_parametrized_name(cls, params: tuple[type[Any], ...]) -> str

Compute the class name for parametrizations of generic classes.

This method can be overridden to achieve a custom naming scheme for generic BaseModels.

Returns

str — String representing the new class where params are passed to cls as type variables.

Parameters

params : tuple[type[Any], ...]

Tuple of types of the class. Given a generic class Model with 2 type variables and a concrete model Model[str, int], the value (str, int) would be passed to params.

Raises
  • TypeError — Raised when trying to generate concrete names for non-generic models.

model_post_init

def model_post_init(context: Any) -> None

Override this method to perform additional initialization after __init__ and model_construct. This is useful if you want to do some validation that requires the entire model to be initialized.

Returns

None

model_rebuild

@classmethod

def model_rebuild(
    cls,
    force: bool = False,
    raise_errors: bool = True,
    _parent_namespace_depth: int = 2,
    _types_namespace: MappingNamespace | None = None,
) -> bool | None

Try to rebuild the pydantic-core schema for the model.

This may be necessary when one of the annotations is a ForwardRef which could not be resolved during the initial attempt to build the schema, and automatic rebuilding fails.

Returns

bool | None — Returns None if the schema is already “complete” and rebuilding was not required. bool | None — If rebuilding was required, returns True if rebuilding was successful, otherwise False.

Parameters

force : bool Default: False

Whether to force the rebuilding of the model schema, defaults to False.

raise_errors : bool Default: True

Whether to raise errors, defaults to True.

_parent_namespace_depth : int Default: 2

The depth level of the parent namespace, defaults to 2.

_types_namespace : MappingNamespace | None Default: None

The types namespace, defaults to None.

model_validate

@classmethod

def model_validate(
    cls,
    obj: Any,
    strict: bool | None = None,
    from_attributes: bool | None = None,
    context: Any | None = None,
    by_alias: bool | None = None,
    by_name: bool | None = None,
) -> Self

Validate a pydantic model instance.

Returns

Self — The validated model instance.

Parameters

obj : Any

The object to validate.

strict : bool | None Default: None

Whether to enforce types strictly.

from_attributes : bool | None Default: None

Whether to extract data from object attributes.

context : Any | None Default: None

Additional context to pass to the validator.

by_alias : bool | None Default: None

Whether to use the field’s alias when validating against the provided input data.

by_name : bool | None Default: None

Whether to use the field’s name when validating against the provided input data.

Raises
  • ValidationError — If the object could not be validated.

model_validate_json

@classmethod

def model_validate_json(
    cls,
    json_data: str | bytes | bytearray,
    strict: bool | None = None,
    context: Any | None = None,
    by_alias: bool | None = None,
    by_name: bool | None = None,
) -> Self

Validate the given JSON data against the Pydantic model.

Returns

Self — The validated Pydantic model.

Parameters

json_data : str | bytes | bytearray

The JSON data to validate.

strict : bool | None Default: None

Whether to enforce types strictly.

context : Any | None Default: None

Extra variables to pass to the validator.

by_alias : bool | None Default: None

Whether to use the field’s alias when validating against the provided input data.

by_name : bool | None Default: None

Whether to use the field’s name when validating against the provided input data.

Raises
  • ValidationError — If json_data is not a JSON string or the object could not be validated.

model_validate_strings

@classmethod

def model_validate_strings(
    cls,
    obj: Any,
    strict: bool | None = None,
    context: Any | None = None,
    by_alias: bool | None = None,
    by_name: bool | None = None,
) -> Self

Validate the given object with string data against the Pydantic model.

Returns

Self — The validated Pydantic model.

Parameters

obj : Any

The object containing string data to validate.

strict : bool | None Default: None

Whether to enforce types strictly.

context : Any | None Default: None

Extra variables to pass to the validator.

by_alias : bool | None Default: None

Whether to use the field’s alias when validating against the provided input data.

by_name : bool | None Default: None

Whether to use the field’s name when validating against the provided input data.


create_model

def create_model(
    model_name: str,
    __config__: ConfigDict | None = None,
    __doc__: str | None = None,
    __base__: None = None,
    __module__: str = __name__,
    __validators__: dict[str, Callable[..., Any]] | None = None,
    __cls_kwargs__: dict[str, Any] | None = None,
    field_definitions: Any | tuple[str, Any] = {},
) -> type[BaseModel]
def create_model(
    model_name: str,
    __config__: ConfigDict | None = None,
    __doc__: str | None = None,
    __base__: type[ModelT] | tuple[type[ModelT], ...],
    __module__: str = __name__,
    __validators__: dict[str, Callable[..., Any]] | None = None,
    __cls_kwargs__: dict[str, Any] | None = None,
    field_definitions: Any | tuple[str, Any] = {},
) -> type[ModelT]

Dynamically creates and returns a new Pydantic model, in other words, create_model dynamically creates a subclass of BaseModel.

Returns

type[ModelT] — The new model.

Parameters

model_name : str

The name of the newly created model.

__config__ : ConfigDict | None Default: None

The configuration of the new model.

__doc__ : str | None Default: None

The docstring of the new model.

__base__ : type[ModelT] | tuple[type[ModelT], ...] | None Default: None

The base class or classes for the new model.

__module__ : str | None Default: None

The name of the module that the model belongs to; if None, the value is taken from sys._getframe(1)

__validators__ : dict[str, Callable[..., Any]] | None Default: None

A dictionary of methods that validate fields. The keys are the names of the validation methods to be added to the model, and the values are the validation methods themselves. You can read more about functional validators here.

__cls_kwargs__ : dict[str, Any] | None Default: None

A dictionary of keyword arguments for class creation, such as metaclass.

**field_definitions : Any | tuple[str, Any] Default: \{\}

Field definitions of the new model. Either:

  • a single element, representing the type annotation of the field.
  • a two-tuple, the first element being the type and the second element the assigned value (either a default or the Field() function).

Raises

  • PydanticUserError — If __base__ and __config__ are both passed.