Rename Names of MultiIndex Pandas Dataframe

Question

I'm in trouble with a dataframe created from a groupby function.

df = base.groupby(['year', 'categ']).agg({'id_prod':'count', 'price':'sum'}).unstack(level=1)

it returns this result:

but I would like to rename id_prod and price to no_sales and revenue but I don't know how to do that because of the MultiIndex

with the print(df.columns) the result is:

MultiIndex([('id_prod', 0),
            ('id_prod', 1),
            ('id_prod', 2),
            (  'price', 0),
            (  'price', 1),
            (  'price', 2)],
           names=[None, 'categ'])

So is this names=[] I would like to change Thanks for your help !

Answer 1

Short and simple, it would just rename your columns with respect to Multi-index

df.columns = df.columns.map('_'.join)

Answer 2

df = df.rename(columns={'id_prod': 'no_sales', 'price': 'revenue'}, level=0)

The level=0 indicates where in the multi-index the keys to be renamed can be found.