Sorting a python array/recarray by column

Question

I have a fairly simple question about how to sort an entire array/recarray by a given column. For example, given the array:

import numpy as np
data = np.a         


        

Answer 1

Here's an extension that works with slices:

import numpy as np
x = np.array([[9, 1, 2],
              [5, 3, 4],
              [0, 5, 6]])

Sorting by rows:

x[:, x[1,:].argsort()] # Sort by second row

array([[1, 2, 9]
       [3, 4, 5]
       [5, 6, 0]])

Sorting by columns:

x[x[:,0].argsort(), :] # Sort by first column

array([[0, 5, 6],
       [5, 3, 4],
       [9, 1, 2]])