diff --git a/pandas/core/groupby/groupby.py b/pandas/core/groupby/groupby.py index c019572f4324e..aa4c7452bcea9 100644 --- a/pandas/core/groupby/groupby.py +++ b/pandas/core/groupby/groupby.py @@ -1297,9 +1297,48 @@ def count(self): @Appender(_doc_template) def mean(self, *args, **kwargs): """ - Compute mean of groups, excluding missing values + Compute mean of groups, excluding missing values. - For multiple groupings, the result index will be a MultiIndex + Returns + ------- + pandas.Series or pandas.DataFrame + + Examples + -------- + >>> df = pd.DataFrame({'A': [1, 1, 2, 1, 2], + ... 'B': [np.nan, 2, 3, 4, 5], + ... 'C': [1, 2, 1, 1, 2]}, columns=['A', 'B', 'C']) + + Groupby one column and return the mean of the remaining columns in + each group. + + >>> df.groupby('A').mean() + >>> + B C + A + 1 3.0 1.333333 + 2 4.0 1.500000 + + Groupby two columns and return the mean of the remaining column. + + >>> df.groupby(['A', 'B']).mean() + >>> + C + A B + 1 2.0 2 + 4.0 1 + 2 3.0 1 + 5.0 2 + + Groupby one column and return the mean of only particular column in + the group. + + >>> df.groupby('A')['B'].mean() + >>> + A + 1 3.0 + 2 4.0 + Name: B, dtype: float64 """ nv.validate_groupby_func('mean', args, kwargs, ['numeric_only']) try: