Sklearn components in pipeline is not fitted even if the whole pipeline is?

Question

I\'m trying to single out a component/transformer from a fitted pipeline to inspect it\'s behavior. However, when I retrieved the component, the component is showed as unfit

Answer 1

The ColumnTransformer attribute transformers is the input unfitted transformers. To access the fitted transformers, use the attribute transformers_ or named_transformers_. I suppose get_params()['preprocessor__cat__imputer'] is also getting the unfitted input transformer.

(You'll still get an error, because the imputer will try to work on the string data as well, and strategy='median' will fail.)