How do I get indices of N maximum values in a NumPy array?

Question

NumPy proposes a way to get the index of the maximum value of an array via np.argmax.

I would like a similar thing, but returning the indexes of the

Answer 1

I think the most time efficiency way is manually iterate through the array and keep a k-size min-heap, as other people have mentioned.

And I also come up with a brute force approach:

top_k_index_list = [ ]
for i in range(k):
    top_k_index_list.append(np.argmax(my_array))
    my_array[top_k_index_list[-1]] = -float('inf')

Set the largest element to a large negative value after you use argmax to get its index. And then the next call of argmax will return the second largest element. And you can log the original value of these elements and recover them if you want.