CODEWITHSUNDEEP
pythonpython-typing
Caridorc
Caridorc

Reputation: 6661

`Iterable[(int, int)]` tuple is not allowed in type hints

I have this very simple code:

from typing import List, Iterable

Position = (int, int)
IntegerMatrix = List[List[int]]

def locate_zeros(matrix: IntegerMatrix) -> Iterable[Position]:
    """Given an NxM matrix find the positions that contain a zero."""
    for row_num, row in enumerate(matrix):
        for col_num, element in enumerate(row):
            if element == 0:
                yield (col_num, row_num)

This is the error:

Traceback (most recent call last):
  File "type_m.py", line 6, in <module>
    def locate_zeros(matrix: IntegerMatrix) -> Iterable[Position]:
  File "/usr/lib/python3.5/typing.py", line 970, in __getitem__
    (len(self.__parameters__), len(params)))
TypeError: Cannot change parameter count from 1 to 2

Why can't I have an iterable of Int pairs as the return type?

Both -> Position and Iterable[Any] work, just not Iterable and Position together don't.

Upvotes: 19

Views: 8962

Answers (1)

Sven Marnach
Sven Marnach

Reputation: 602285

You should use typing.Tuple[int, int] to declare the tuple type Position, not (int, int).

Upvotes: 21

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