Python n Periode STD
s = pd.Series([5, 5, 6, 7, 5, 5, 5])
>>> s.rolling(3).std()
0 NaN
1 NaN
2 5.773503e-01
3 1.000000e+00
4 1.000000e+00
5 1.154701e+00
6 2.580957e-08
dtype: float64
Bloody Buffalo