Home/ Questions/Q 6817437
In Process

The Archive Base Latest Questions

Editorial Team
  • 0
Asked: 2026-05-26T21:03:17+00:00

I’ve got a 2D numpy array, A containing an index into another array, B

  • 0

I’ve got a 2D numpy array, A containing an index into another array, B. What is a good way to get C from A and B using numpy?

A = array([[1, 1, 0, 2],
           [1, 0, 0, 2],
           [1, 1, 0, 2]])

B = array([0, 5, 3])

C = array([[5, 5, 0, 3],
           [5, 0, 0, 3],
           [5, 5, 0, 3]])
Share

Leave an answer

You must login to add an answer.

Need An Account,

1 Answer

  1. Editorial Team

    How about this C = B[A]. That’s the beauty of numpy:

    In [1]: import numpy as np
In [2]: A = np.array([[1, 1, 0, 2],
   ...:            [1, 0, 0, 2],
   ...:            [1, 1, 0, 2]])

In [3]: B = np.array([0, 5, 3])

In [4]: B[A]
Out[4]: 
array([[5, 5, 0, 3],
       [5, 0, 0, 3],
       [5, 5, 0, 3]])
    • 0