How to type hint a dictionary with values of different types

by

You are looking for TypedDict. It is currently only a mypy-only extension, but there are plans to make it an officially sanctioned type in the near-future. I am not sure if PyCharm supports this feature yet, though.

So, in your case, you’d do:

from mypy_extensions import TypedDict

RectangleElements = TypedDict('RectangleElements', {
    'front': Line,
    'left': Line,
    'right': Line,
    'rear': Line,
    'cog': float,
    'area': float,
    'pins': Optional[List[Pin]]
})

class Rectangle:
    def __init__(self, corners: Tuple[Tuple[float, float]], **kwargs):
        self.x, self.z = corners[0][0], corners[0][1]
        self.elements = {
            'front': Line(corners[0], corners[1]),
            'left': Line(corners[0], corners[2]),
            'right': Line(corners[1], corners[3]),
            'rear': Line(corners[3], corners[2]),
            'cog': calc_cog(corners),
            'area': calc_area(corners),
            'pins': None
        }  # type: RectangleElements

If you are using Python 3.6+, you can type this all more elegantly using the class-based syntax.

In your specific case though, I think most people would just store those pieces of data as regular fields instead of a dict. I’m sure you’ve already thought through the pros and cons of that approach though, so I’ll skip lecturing you about it.

More Related Contents:

  1. How do I type hint a method with the type of the enclosing class?
  2. How can I tell PyCharm what type a parameter is expected to be?
  3. Can you annotate return type when value is instance of cls?
  4. Python 3 dictionary with known keys typing
  5. Difference between defining typing.Dict and dict?
  6. How do I annotate types in a for-loop?
  7. What is the type hint for a (any) python module?
  8. How to specify multiple return types using type-hints
  9. Type hinting a collection of a specified type
  10. What are type hints in Python 3.5?
  11. Using the class as a type hint for arguments in its methods [duplicate]
  12. How to use type hints in python 3.6?
  13. Type annotations for *args and **kwargs
  14. What’s the difference between a constrained TypeVar and a Union?
  15. typing: Dynamically Create Literal Alias from List of Valid Values
  16. Exclude type in Python typing annotation
  17. Specify length of Sequence or List with Python typing module
  18. Defining a recursive type hint in Python?
  19. Can I omit Optional if I set default to None?
  20. Using List/Tuple/etc. from typing vs directly referring type as list/tuple/etc
  21. mypy, type hint: Union[float, int] -> is there a Number type?
  22. Name not defined in type annotation [duplicate]
  23. Python 3.5 type hinting does not result in an error
  24. Type hints in namedtuple
  25. How to annotate function that takes a tuple of variable length? (variadic tuple type annotation)
  26. typing.Any vs object?
  27. Python typing for module type
  28. Recursive Typing in Python 3.5+ [duplicate]
  29. Python type hint for classes that support __getitem__
  30. How to annotate a type that’s a class object (instead of a class instance)?

Leave a Comment