In [1]: import numpy as np
In [2]: import pandas as pd
In [3]: df = pd.DataFrame({'A': list('XYZXYZXYZX'), 'B': [1, 2, 1, 3, 1, 2, 3, 3, 1, 2],
'C': [12, 14, 11, 12, 13, 14, 16, 12, 10, 19]})
In [4]: df.groupby('A')['B'].agg({'mean': np.mean, 'standard deviatio...