How to change the order of DataFrame columns?

Question

I have the following DataFrame (df):

import numpy as np
import pandas as pd

df = pd.DataFrame(np.random.rand(10, 5))

Answer 1

Here is a very simple answer to this(only one line).

You can do that after you added the 'n' column into your df as follows.

import numpy as np
import pandas as pd

df = pd.DataFrame(np.random.rand(10, 5))
df['mean'] = df.mean(1)
df
           0           1           2           3           4        mean
0   0.929616    0.316376    0.183919    0.204560    0.567725    0.440439
1   0.595545    0.964515    0.653177    0.748907    0.653570    0.723143
2   0.747715    0.961307    0.008388    0.106444    0.298704    0.424512
3   0.656411    0.809813    0.872176    0.964648    0.723685    0.805347
4   0.642475    0.717454    0.467599    0.325585    0.439645    0.518551
5   0.729689    0.994015    0.676874    0.790823    0.170914    0.672463
6   0.026849    0.800370    0.903723    0.024676    0.491747    0.449473
7   0.526255    0.596366    0.051958    0.895090    0.728266    0.559587
8   0.818350    0.500223    0.810189    0.095969    0.218950    0.488736
9   0.258719    0.468106    0.459373    0.709510    0.178053    0.414752


### here you can add below line and it should work 
# Don't forget the two (()) 'brackets' around columns names.Otherwise, it'll give you an error.

df = df[list(('mean',0, 1, 2,3,4))]
df

        mean           0           1           2           3           4
0   0.440439    0.929616    0.316376    0.183919    0.204560    0.567725
1   0.723143    0.595545    0.964515    0.653177    0.748907    0.653570
2   0.424512    0.747715    0.961307    0.008388    0.106444    0.298704
3   0.805347    0.656411    0.809813    0.872176    0.964648    0.723685
4   0.518551    0.642475    0.717454    0.467599    0.325585    0.439645
5   0.672463    0.729689    0.994015    0.676874    0.790823    0.170914
6   0.449473    0.026849    0.800370    0.903723    0.024676    0.491747
7   0.559587    0.526255    0.596366    0.051958    0.895090    0.728266
8   0.488736    0.818350    0.500223    0.810189    0.095969    0.218950
9   0.414752    0.258719    0.468106    0.459373    0.709510    0.178053