typingx

How many times have you wanted to check the shape of your data either in application code or while testing? With this library, you can leverage typing types at runtime to do that!

# Check if `my_list` is a list of integers
isinstancex(my_list, [int])  # shortcut for typing.List[int]

# Check if `my_list` has only numbers (3.10 syntax)
isinstancex([3, 4, 3.14], list[int | float])

# Check if `my_list` starts with 2 integers and then has only strings
isinstancex(my_list, [int, int, str, ...])  # shortcut for Listx[int, int, str, ...] (see extra types)

# Check if `my_dict` is a mapping between integers and strings
isinstancex(my_dict, {int: str})  # shortcut for `typing.Dict[int, str]`

# Check deeper the shape of `my_dict`
isinstancex(my_dict, {'a': int, 'b': bool, ...: str})  # shortcut for `typing.TypedDict`

Since typing changed a lot since python 3.6, this library also makes sure the whole behaviour is consistent with 3.10 for all python versions.

It hence provides:

• isinstancex: like isinstance but with typing types and extra types provided by this library
• get_args and get_origin that have the exact same behaviour as the 3.10 python version ones, no matter which python version is used (the only exception being get_args with Generic on python 3.6)
• is_literal, is_newtype, is_typeddict helpers
• most typing types but with homogeneous behaviour (e.g. with 3.8, this libray will choose typing_extensions.TypedDict instead of typing.TypedDict since the latter doesn't store information to distinguish optional and required keys)
• extanded types:
  • TypedDict with ... field to allow type checking on optional fields
• extra types:
  • Listx and Tuplex: more sophisticated versions of List and Tuple to add ... anywhere in the parameters

Installation

    pip install typingx

Usage

from collections import ChainMap, Counter

from typingx import *

# Dict
assert isinstancex({"a": 1, "b": 2}, Dict[str, int]) is True
assert isinstancex({"a": 1, "b": 2}, Dict[str, str]) is False
assert isinstancex({"a": 1, "b": 2}, Dict[int, str]) is False
assert isinstancex({"a": 1, "b": 2}, Dict[str, Any]) is True

# Dict (shortcut)
assert isinstancex({"a": 1, "b": 2}, {str: int}) is True

# List
assert isinstancex([1, 2, 3], List[int]) is True
assert isinstancex([1, 2, "q"], List[int]) is False
assert isinstancex([1, 2, "q"], List[Union[str, int]]) is True

# Listx
assert isinstancex([1, 2, 3, 4], Listx[int]) is True
assert isinstancex([1, 2, "q"], Listx[int, ..., str]) is True
assert isinstancex([1, 2, "q", "w", "e"], Listx[int, ..., str]) is False
assert isinstancex([1, 2, "q", "w", "e"], Listx[int, ..., str, ...]) is True
assert isinstancex([1, 2, "q", "w", b"xyz", "e"], Listx[int, ..., str, ...]) is False
assert isinstancex([1, 2, "q", "w", b"xyz", "e"], Listx[int, ..., Union[str, bytes], ...]) is True

# Listx (shortcut)
assert isinstancex([1, 2, 3, 4, "q"], [int, ..., str]) is True

# Literal
assert isinstancex("a", Literal["a"]) is True
assert isinstancex(Literal["a"], Literal["a"]) is True
assert isinstancex("b", Literal["a"]) is False
assert isinstancex("b", Literal["a", Literal[Literal["b"]]]) is True
assert isinstancex(Literal["a", "b"], Literal["b", "a", "c"]) is True

# Mapping
assert isinstancex(Counter({"red": 4, "blue": 2}), Mapping[str, int]) is True
assert isinstancex(ChainMap({"art": "van gogh"}, {"music": "bach"}), Mapping[str, str]) is True

# NewType
UserId = NewType("UserId", int)
ProUserId = NewType("ProUserId", UserId)

assert isinstancex(1, UserId) is True
assert isinstancex(1, ProUserId) is True
assert isinstancex(UserId(1), UserId) is True
assert isinstancex("3", UserId) is False

# None
assert isinstancex([None, None], List[None]) is True
assert isinstancex([None, None], List[NoneType]) is True
assert isinstancex([None, None], List[type(None)]) is True
assert isinstancex([None, None], List[Literal[None]]) is True

# Sequence
assert isinstancex("abc", Sequence[Any]) is True
assert isinstancex("abc", Sequence[int]) is False
assert isinstancex((1, 3, 5), Sequence[int]) is True

# Set
assert isinstancex({"a", "b"}, Set[str]) is True
assert isinstancex({"a", "b"}, Set[int]) is False
# Can be written with the shortcut!
assert isinstancex({"a", "b"}, {str}) is True

# Tuple
assert isinstancex((1, 2), Tuple[int, ...]) is True
assert isinstancex((1, 2), Tuple[int, int]) is True
assert isinstancex((1, 2), Tuple[int, int, int]) is False

# Tuplex
assert isinstancex((3, "a", "b"), Tuplex[int, str, ...]) is True
assert isinstancex((3, "a", "b", "c"), Tuplex[int, str, ...]) is True
assert isinstancex((3, "a", "b", "c"), Tuplex[int, str, ..., bool]) is False
assert isinstancex((3, "a", "b", "c", True), Tuplex[int, str, ..., bool]) is True
assert isinstancex((3, "a", "b", "c", 3), Tuplex[int, str, ..., bool]) is False
assert isinstancex((3, "a", "b", "c", True, False), Tuplex[int, str, ..., bool, ...]) is True

# Type
class User: ...
class BaseUser(User): ...

assert isinstancex(BaseUser, Type[BaseUser]) is True
assert isinstancex(BaseUser, Type[User]) is True
assert isinstancex(User, Type[User]) is True
assert isinstancex(User, Type[BaseUser]) is False

# TypedDict
FullMovie = TypedDict("FullMovie", {"name": str, "year": int})

class PartialMovie(TypedDict, total=False):
    name: str
    year: int

class ExtraMovie(TypedDict):
    name: str
    year: int
    __extra__: str

assert isinstancex({"name": "The Matrix", "year": 1999}, FullMovie) is True
assert isinstancex({"name": "The Matrix", "year": "1999"}, FullMovie) is False
assert isinstancex({"name": "The Matrix"}, FullMovie) is False
assert isinstancex({"name": "The Matrix", "year": 1999, "extra": "qwe"}, FullMovie) is False

assert isinstancex({"name": "The Matrix", "year": 1999}, PartialMovie) is True
assert isinstancex({"name": "The Matrix"}, PartialMovie) is True
assert isinstancex({"name": "The Matrix", "year": 1999, "extra": "qwe"}, PartialMovie) is False

assert isinstancex({"name": "The Matrix", "year": 1999}, ExtraMovie) is True
assert isinstancex({"name": "The Matrix", "year": 1999, "q": "w", "e": "r"}, ExtraMovie) is True
assert isinstancex({"name": "The Matrix", "year": 1999, "q": "w", "e": 1}, ExtraMovie) is False

# TypedDict (shortcut)
assert isinstancex({"name": "The Matrix", "year": 1999, "q": "w", "e": "r"}, {"name": str, "year": int, ...: str}) is True