Itertools update #1233
Itertools update #1233
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| @@ -44,20 +44,18 @@ def islice(iterable: Iterable[_T], stop: int) -> Iterator[_T]: ... | |||
| def islice(iterable: Iterable[_T], start: int, stop: Optional[int], | |||
| step: int = ...) -> Iterator[_T]: ... | |||
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| def starmap(func: Any, iterable: Iterable[Any]) -> Iterator[Any]: ... | |||
| def starmap(func: Callable[..., _S], iterable: Iterable[Iterable[Any]]) -> Iterator[_S]: ... | |||
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Can this work with both _T and _S?
i.e.
def starmap(func: Callable[[_T], _S], iterable: Iterable[Iterable[_T]]) -> Iterator[_S]: ...
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No, because the elements in the iterable can have different types and they are unpacked as arguments for the callable. So I guess theoretically it would have to be something like this:
def starmap(func: Callable[_T, _S], iterable: Iterable[_T]) -> Iterator[_S]: ...
But that is not possible. As an example, itertools.starmap(lambda x, y: x * len(y), [(5, 'abc'), (2, 'xy')]) would be completely valid, but is impossible to fully generically type with the current system.
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Oops. Missed the * in func(*seq[0]) Oh well.
stdlib/3/itertools.pyi
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| def permutations(iterable: Iterable[_T], | ||
| r: Union[int, None] = ...) -> Iterator[Sequence[_T]]: ... | ||
| r: int = ...) -> Iterator[Tuple[_T, ...]]: ... |
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r should probably be Optional[int]
Added back optionality of second argument for itertools.permutations.
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The Travis failure appears to be a mypy bug (python/mypy#3301). |
stdlib/3/itertools.pyi
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| # TODO: Return type should be Iterator[Tuple[..]], but unknown tuple shape. | ||
| # Iterator[Sequence[_T]] loses this type information. | ||
| def product(*p: Iterable[_T], repeat: int = ...) -> Iterator[Sequence[_T]]: ... | ||
| def product(*p: Iterable[_T], repeat: Optional[int] = ...) -> Iterator[Tuple[_T, ...]]: ... |
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I don't think repeat is Optional; I get TypeError: 'NoneType' object cannot be interpreted as an integer in 3.6.
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My bad, I accidentially put the Optional on the wrong function -.-
Moved the Optional which I accidentially put on the wrong function -.-
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Thank you! |
* Updated the typehints for itertools. * Removed the overload because it caused problems and cleaned up the imports. * Update itertools.pyi Added back optionality of second argument for itertools.permutations. * Update itertools.pyi Moved the Optional which I accidentially put on the wrong function -.-
Some of the typehints for the itertools module were not specific enough. For example, the combinatorics generators all yield tuples and not any sequence. I made the type information more specific where it is possible.