In Pandas, I can specify the levels of a Categorical type myself: MyCat = pd.CategoricalDtype(categories=['A','B','C'], ordered=True) my_data = pd.Series(['A','A','B'], dtype=MyCat) This means that I can make sure that different columns and sets use the same dtype I can specify an ordering for the levels. Is there a way to do this with Polars? I know you can use the string cache feature to achieve 1) in a different way, however I'm interested if my dtype/levels can be specified directly. I'm not aware of any way to achieve 2), however I think the categorical dtypes in Arrow do allow an optional ordering, so maybe it's possible? Continue reading...