prices.loc['2023-01'] *= 1 You can always do df.to_pandas() ... prices.loc['2023-01'] *= 1 ... from_pandas() :) More seriously, you are right, this is a tough

prices.loc['2023-01'] *= 1 You can always do df.to_pandas() ... prices.loc['2023-01'] *= 1 ... from_pandas() :) More seriously, you are right, this is a tough one to do in polars. Polars seems to want to work with whole columns at a time, it doesn't give you write access to row sets.