Column naming: compatibility with OneHotEncoder

[stacymiller]

In sklearn v0.24.1 OneHotEncoder transformer exposes derived names in the categories_ attribute. Can we add one more check to

sklearn-pandas/sklearn_pandas/dataframe_mapper.py

Line 40 in e842746

def _get_feature_names(estimator):

to cover this case?

[ragrawal]

Sure, can you create a MR and add a unit test. I will be happy to merge it.

[falcaopetri]

The categories_ attribute does not represent the derived feature names. It actually contains The categories of each feature determined during fitting, see OneHotEncoder.categories_).

Nonetheless, sklearn 1.0 transformer's get_output_names is getting deprecated in favor of get_feature_names_out. More info in PR #248.