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

How about:

df.insert(0, 'mean', df.mean(1))

http://pandas.pydata.org/pandas-docs/stable/dsintro.html#column-selection-addition-deletion