What is an alternative to retrieving diagonal elements without looping or calling np.diag()?
Question:
I have a 4×4 array, A1, and need to retrieve its diagonal elements without looping or calling np.diag(). What’s a way of doing so? Appreciate your help!
A1 = np.array([ [1, 4, 6, 8],[2, 5, 7, 10],[3, 6, 9, 13], [11, 12, 16, 0]])
Answers:
by indexing using the indices of the diagonal, which are the indices of the non-zeros of an identity matrix.
import numpy as np
A1 = np.array([ [1, 4, 6, 8],[2, 5, 7, 10],[3, 6, 9, 13], [11, 12, 16, 0]])
diag_pos = np.eye(A1.shape[0],dtype=bool).nonzero()
print(A1[diag_pos])
[1 5 9 0]
I have a 4×4 array, A1, and need to retrieve its diagonal elements without looping or calling np.diag(). What’s a way of doing so? Appreciate your help!
A1 = np.array([ [1, 4, 6, 8],[2, 5, 7, 10],[3, 6, 9, 13], [11, 12, 16, 0]])
by indexing using the indices of the diagonal, which are the indices of the non-zeros of an identity matrix.
import numpy as np
A1 = np.array([ [1, 4, 6, 8],[2, 5, 7, 10],[3, 6, 9, 13], [11, 12, 16, 0]])
diag_pos = np.eye(A1.shape[0],dtype=bool).nonzero()
print(A1[diag_pos])
[1 5 9 0]