pandas.core.groupby.GroupBy.mean

Compute mean of groups, excluding missing values.

return

pandas.Series or pandas.DataFrame

Limitations

• This function may reveal slower performance than Pandas* on user system. Users should exercise a tradeoff between staying in JIT-region with that function or going back to interpreter mode.

Examples

Compute mean of groups, excluding missing values.

import pandas as pd
from numba import njit


@njit
def df_groupby_mean():
    df = pd.DataFrame({'A': [1, 2, 3, 1, 2, 3, 3, 3, 2],
                       'B': [0, 1, 5, 0, 2, 4, 3, 2, 3],
                       'C': [1, 2, 3, 4, 5, 6, 7, 8, 9]})
    out_df = df.groupby('A').mean()

    # Expect DataFrame of
    # {'B': [0.0, 2.0, 3.5], 'C': [2.500000, 5.333333, 6.000000} with index=[1, 2, 3]
    return out_df


print(df_groupby_mean())

$ python ./dataframe/groupby/dataframe_groupby_mean.py
     B         C
1  0.0  2.500000
2  2.0  5.333333
3  3.5  6.000000

See also

Series.groupby

Group Series using a mapper or by a Series of columns.

DataFrame.groupby

Group DataFrame using a mapper or by a Series of columns.