Examples
Difference with previous row

In [1]:
import numpy as np
import pandas as pd
In [2]:
s = pd.Series([2, 2, 3, 4, 5])
s.diff()
Out[2]:
0    NaN
1    0.0
2    1.0
3    1.0
4    1.0
dtype: float64

Difference with 3rd previous row

In [3]:
s.diff(periods=3)
Out[3]:
0    NaN
1    NaN
2    NaN
3    2.0
4    3.0
dtype: float64

Difference with following row

In [4]:
s.diff(periods=-2)
Out[4]:
0   -1.0
1   -2.0
2   -2.0
3    NaN
4    NaN
dtype: float64