order columns by values by pandas code example

Example 1: sort a dataframe by a column valuepython

>>> df.sort_values(by=['col1'])
    col1 col2 col3
0   A    2    0
1   A    1    1
2   B    9    9
5   C    4    3
4   D    7    2
3   NaN  8    4

Example 2: sort dataframe by column

df.sort_values(by='col1', ascending=False)