Mistake in maths/average_mode.py fixed.

[haningrisha]

Describe your change:

• Mistake in maths/average_mode.py fixed. The previous solution was to return the
  value on the first loop iteration, which is not correct, more than that it
  used to delete repeating values, so result's array and check array lost
  relation between each other

• Type hint added

• Add an algorithm?

• Fix a bug or typo in an existing algorithm?

• Documentation change?

Checklist:

• I have read CONTRIBUTING.md.
• This pull request is all my own work -- I have not plagiarized.
• I know that pull requests will not be merged if they fail the automated tests.
• This PR only changes one algorithm file. To ease review, please open separate PRs for separate algorithms.
• All new Python files are placed inside an existing directory.
• All filenames are in all lowercase characters with no spaces or dashes.
• All functions and variable names follow Python naming conventions.
• All function parameters and return values are annotated with Python type hints.
• All functions have doctests that pass the automated testing.
• All new algorithms have a URL in its comments that points to Wikipedia or other similar explanation.
• If this pull request resolves one or more open issues then the commit message contains Fixes: #{$ISSUE_NO}.

[mrmaxguns]

Thank you so much for this critical bug fix. The original mode function didn't actually return the mode of the input list, and instead always returned the first value of the list (since the return was inside the loop, thus happening at the first iteration).

The reason why the bug wasn't caught was because the value that was the mode always happened to be at the front of the list. More varying tests should prevent future mistakes like this.

Here is my review. If you disagree with any of the points, feel free to comment on them.

[mrmaxguns]

Pre-commit failed because Black would reformat the file. Make sure to run black with black your_file.py. Black can be installed with pip install black.

[haningrisha]

I was thinking about raising an exception in case the list has several modes(for instance [2,2,1,1]) several modes existence fact may be crucial in some algorithms. Also, I can add another function for working with multiple mode cases.

Example of usage:

try:
    m = mode(some list)
    # logic
except SeveralModeException:
    m = multiple_modes(some list)
    # logic with list

Or I can return a list even if there's only one mode, but this seems odd.

What do you think?

[mrmaxguns]

I was thinking about raising an exception in case the list has several modes(for instance [2,2,1,1]) several modes existence fact may be crucial in some algorithms. Also, I can add another function for working with multiple mode cases.

Example of usage:

try:
    m = mode(some list)
    # logic
except SeveralModeException:
    m = multiple_modes(some list)
    # logic with list

Or I can return a list even if there's only one mode, but this seems odd.

What do you think?

Personally, I like the one-function approach. A second function that performs almost the same task seems redundant. There could just be one function which always returns a list. That way, the user can check the length by themselves. This also means that the function could return an empty list if the input list is empty.

[mrmaxguns]

Thanks for the changes. Here is my review.

[mrmaxguns]

Instead of creating a list, then converting it to a set, and then back to a list, you could do a set comprehension. Also, sorted takes any iterable, so passing a set to it (instead of converting it to a list first) will work.

Suggested change

	result = [input_list[i] for i, value in enumerate(result) if value == y]
	result = list(set(result)) # Deletes duplicates
	result = {input_list[i] for i, value in enumerate(result) if value == y}

[mrmaxguns]

Thank you for contributing 🎉