typing

Various type annotation aids.

Type Hints

PathLike	Type hint for objects that represent filesystem paths.
PathType	Invariant TypeVar constrained to str, pathlib.Path and os.PathLike.
AnyNumber	Type hint for numbers.
WrapperDescriptorType	The type of methods of some built-in data types and base classes.
MethodWrapperType	The type of bound methods of some built-in data types and base classes.
MethodDescriptorType	The type of methods of some built-in data types.
ClassMethodDescriptorType	The type of unbound class methods of some built-in data types.

PathLike

Type hint for objects that represent filesystem paths.

See also

domdf_python_tools.typing.PathType

Alias of Union[str, Path, PathLike]

PathType = TypeVar(PathType, str, Path, PathLike)

Type:    TypeVar

Invariant TypeVar constrained to str, pathlib.Path and os.PathLike.

Type variable for objects that represent filesystem paths.

New in version 2.2.0.

See also

domdf_python_tools.typing.PathLike

AnyNumber

Type hint for numbers.

Changed in version 0.4.6: Moved from domdf_python_tools.pagesizes

Alias of Union[float, int, Decimal]

WrapperDescriptorType

The type of methods of some built-in data types and base classes, such as object.__init__() or object.__lt__().

New in version 0.8.0.

MethodWrapperType

The type of bound methods of some built-in data types and base classes. For example, it is the type of object().__str__.

New in version 0.8.0.

MethodDescriptorType

The type of methods of some built-in data types, such as str.join().

New in version 0.8.0.

ClassMethodDescriptorType

The type of unbound class methods of some built-in data types, such as dict.__dict__['fromkeys'].

New in version 0.8.0.

Protocols

JsonLibrary	typing.Protocol for libraries that implement the same API as json.
HasHead	typing.Protocol for classes that have a head method.
String	Protocol for classes that implement __str__.
FrameOrSeries	Invariant TypeVar constrained to pandas.Series and pandas.DataFrame.
SupportsIndex	typing.Protocol for classes that support __index__.
SupportsLessThan	typing.Protocol for classes that support __lt__.
SupportsLessEqual	typing.Protocol for classes that support __le__.
SupportsGreaterThan	typing.Protocol for classes that support __gt__.
SupportsGreaterEqual	typing.Protocol for classes that support __ge__.

protocol JsonLibrary

Bases: Protocol

typing.Protocol for libraries that implement the same API as json.

Useful for annotating functions which take a JSON serialisation-deserialisation library as an argument.

Classes that implement this protocol must have the following methods / attributes:

static dumps(obj, *, skipkeys=..., ensure_ascii=..., check_circular=..., allow_nan=..., cls=..., indent=..., separators=..., default=..., sort_keys=..., **kwds)

Serialize obj to a JSON formatted str.

Parameters

• obj (Any)

• skipkeys (bool)

• ensure_ascii (bool)

• check_circular (bool)

• allow_nan (bool)

• cls (Optional[Type[JSONEncoder]])

• indent (Union[None, int, str])

• separators (Optional[Tuple[str, str]])

• default (Optional[Callable[[Any], Any]])

• sort_keys (bool)

• kwds

Return type

str

static loads(s, *, cls=..., object_hook=..., parse_float=..., parse_int=..., parse_constant=..., object_pairs_hook=..., **kwds)

Deserialize s to a Python object.

Parameters

• s (Union[str, bytes])

• cls (Optional[Type[JSONDecoder]])

• object_hook (Optional[Callable[[Dict[Any, Any]], Any]])

• parse_float (Optional[Callable[[str], Any]])

• parse_int (Optional[Callable[[str], Any]])

• parse_constant (Optional[Callable[[str], Any]])

• object_pairs_hook (Optional[Callable[[List[Tuple[Any, Any]]], Any]])

• kwds

Return type

Any

protocol HasHead

Bases: Protocol

typing.Protocol for classes that have a head method.

This includes pandas.DataFrame and pandas.Series.

New in version 0.8.0.

This protocol is runtime checkable.

Classes that implement this protocol must have the following methods / attributes:

head(n=5)

Return the first n rows.

Parameters

n (int) – Number of rows to select. Default 5.

Return type

HasHead

Returns

The first n rows of the caller object.

to_string(*args, **kwargs)

Render the object to a console-friendly tabular output.

Return type

Optional[str]

protocol String

Bases: Protocol

Protocol for classes that implement __str__.

Changed in version 0.8.0: Moved from domdf_python_tools.stringlist.

This protocol is runtime checkable.

Classes that implement this protocol must have the following methods / attributes:

__str__()

Return str(self).

Return type

str

protocol FrameOrSeries

New in version 1.0.0.

Classes that implement this protocol must have the following methods / attributes:

protocol SupportsIndex

Bases: Protocol

typing.Protocol for classes that support __index__.

New in version 2.0.0.

Classes that implement this protocol must have the following methods / attributes:

__index__()

Return type

int

protocol SupportsLessThan

Bases: Protocol

typing.Protocol for classes that support __lt__.

New in version 3.0.0.

Classes that implement this protocol must have the following methods / attributes:

__lt__(_SupportsLessThan__other)

Return self < value.

Return type

bool

protocol SupportsLessEqual

Bases: Protocol

typing.Protocol for classes that support __le__.

New in version 3.0.0.

Classes that implement this protocol must have the following methods / attributes:

__le__(_SupportsLessEqual__other)

Return self <= value.

Return type

bool

protocol SupportsGreaterThan

Bases: Protocol

typing.Protocol for classes that support __gt__.

New in version 3.0.0.

Classes that implement this protocol must have the following methods / attributes:

__gt__(_SupportsGreaterThan__other)

Return self > value.

Return type

bool

protocol SupportsGreaterEqual

Bases: Protocol

typing.Protocol for classes that support __ge__.

New in version 3.0.0.

Classes that implement this protocol must have the following methods / attributes:

__ge__(_SupportsGreaterEqual__other)

Return self >= value.

Return type

bool

Utility Functions

check_membership(obj, type_)

Check if the type of obj is one of the types in a typing.Union, typing.Sequence etc.

Parameters

• obj (Any) – The object to check the type of

• type_ (Union[Type, object]) – A Type that has members, such as a typing.List, typing.Union or typing.Sequence.

Return type

bool