Sorting a 2D numpy array by multiple axes

Question

I have a 2D numpy array of shape (N,2) which is holding N points (x and y coordinates). For example:

array([[3, 2],
       [6, 2],
       [3, 6],
       [3,          


        

Answer 1

The numpy_indexed package (disclaimer: I am its author) can be used to solve these kind of processing-on-nd-array problems in an efficient fully vectorized manner:

import numpy_indexed as npi
npi.sort(a)  # by default along axis=0, but configurable