How to shift a column in Pandas DataFrame

You need to use df.shift here.
df.shift(i) shifts the entire dataframe by i units down.

So, for i = 1:

Input:

    x1   x2  
0  206  214  
1  226  234  
2  245  253  
3  265  272    
4  283  291

Output:

    x1   x2
0  Nan  Nan   
1  206  214  
2  226  234  
3  245  253  
4  265  272 

So, run this script to get the expected output:

import pandas as pd

df = pd.DataFrame({'x1': ['206', '226', '245',' 265', '283'],
                   'x2': ['214', '234', '253', '272', '291']})

print(df)
df['x2'] = df['x2'].shift(1)
print(df)

In [18]: a
Out[18]: 
   x1  x2
0   0   5
1   1   6
2   2   7
3   3   8
4   4   9

In [19]: a['x2'] = a.x2.shift(1)

In [20]: a
Out[20]: 
   x1  x2
0   0 NaN
1   1   5
2   2   6
3   3   7
4   4   8