count consecutive elements

[Peter Otten]

On 17/01/2021 02:15, Dan Stromberg wrote:

IMO a good set of tests is much more important than type annotations ;)

>    def get_longest(string: str) -> typing.Tuple[int, typing.List[str]]:
>        """Get the longest run of a single consecutive character."""

May I ask why you artificially limit the signature to str?
If there were a signature, shouldn't it be something like

Iterable[E] --> Tuple[int, List[E]]

where E may be anything that has an equality operation?
As someone who has not yet looked seriously into typing: is there a way 
to spell this?

>        if not string:
>            return (0, [])
>        grouped = itertools.groupby(string)
>        grouped_with_lengths = [(len(list(value)), key) for key, value in
> grouped]
>        max_count_and_letter = max(grouped_with_lengths)
>        max_count = max_count_and_letter[0]
>        result = (max_count, sorted(list_ for count, list_ in
> grouped_with_lengths if count == max_count))
>        return result

If you want to dabble some more here's a test case you might strive for 
your function to pass:

"""
     >>> class A:
     ...     def __init__(self, x):
     ...         self.x = x
     ...     def __eq__(self, other):
     ...         return self.x == other.x
     ...     def __repr__(self):
     ...         return self.x

     >>> get_longest(map(A, "aaabbcccdaa"))
     (3, [a, c])

"""