setting values in a dataframe with duplicated keys
I have a dataframe with duplicated keys, and I need to assign values to some column of that dataframe, for some different keys. Dataframe indexes support duplicated keys, so I assume that this kind of work should be easy, if not I don't see why dataframes should be allowed to have duplicated keys. Anyway, setting the values like this:

    df.loc[key, 'column']= vector

gives me the following error:

    ValueError: Must have equal len keys and value when setting with an iterable

even if the number of times `key` appears in the index of `df` is equal to the length of `vector`. I think this should be fixed.

Thank you,
c. foschi