Add audeer.unique()

[hagenw]

It might be that a user wants to get unique values of a sequence, in the order they are appearing in that sequence.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 100.0%. Comparing base (ec72190) to head (e108c98). Report is 2 commits behind head on main.

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[hagenw]

typing.Sequence should be fine as the code will work with every object that implements __iter__.

But to support that, it is usually easier to convert everything to a fixed output type, instead of returning the original type. I also prefer to have a fixed output type in basic functions instead of defining the output type by the input type.

[ChristianGeng]

typing.Sequence should be fine as the code will work with every object that implements __iter__.

But to support that, it is usually easier to convert everything to a fixed output type, instead of returning the original type. I also prefer to have a fixed output type in basic functions instead of defining the output type by the input type.

I see: a DataFrame is not a sequence:

import pandas as pd
import collections.abc
df = pd.DataFrame.from_dict({
    'v1': [1,2,1,2,4,1],
    'v2': [2,4,4,2,3,1],
    }
)
typecheck = isinstance(df, collections.abc.Sequence)
print(typecheck)
print(df.__iter__)

results in

False
<bound method NDFrame.__iter__ of    v1  v2
0   1   2
1   2   4
2   1   4
3   2   2
4   4   3
5   1   1>

In other words: pd.Dataframe implements __iter__ but the object is not a sequence. Interestingly, a pd.Series is not a sequence either. Still unique works on it.

ser = pd.Series([1,2,1,2,4,1])
isinstance(ser, collections.abc.Sequence)
>>> False

But I am happy with it and will approve it as this becomes to academic. I think one should add a string to the test case and then I will approve.

[ChristianGeng]

I accidentally pressed the "close" button next to the comment button. Reopening. Apologies.

[hagenw]

In the current Python documentation, they write:

and we have

>>> isinstance(pd.Series([1]), collections.abc.Iterable)
True

So I changed the type to typing.Iterable, which seems to be a better fit to me. Do you agree?

[ChristianGeng]

So I changed the type to typing.Iterable, which seems to be a better fit to me. Do you agree?

Yes. A DataFrame is also an iterable though. I have approved already - it is probably hard to impossible to completely get it right with the python typing system: when one goes through the tests one can see what is going on. Alright with me.