Fastest way to sort each row in a pandas dataframe

Question

I need to find the quickest way to sort each row in a dataframe with millions of rows and around a hundred columns.

So something like this:

A   B   C         


        

Answer 1

Instead of using pd.DataFrame constructor, an easier way to assign the sorted values back is to use double brackets:

original dataframe:

A   B   C   D
3   4   8   1
9   2   7   2

df[['A', 'B', 'C', 'D']] = np.sort(df)[:, ::-1]

   A  B  C  D
0  8  4  3  1
1  9  7  2  2

This way you can also sort a part of the columns:

df[['B', 'C']] = np.sort(df[['B', 'C']])[:, ::-1]

   A  B  C  D
0  3  8  4  1
1  9  7  2  2