How can I find out the index of an element from row and column in Python

Question

I have the rows and columns of a matrix and need to find the index. In my case I have a 6x6 matrix and would like to
find the index of the data at [3,3]

here's my code

[code]
heatmap = np.zeros((6,6), dtype=int);
index? = someFuction(heatmap[r,c]);
[/code]

Answer 1

You probably want to use np.ravel_multi_index:

[code]
import numpy as np
heatmap = np.zeros((6,6), dtype=int)
index = np.ravel_multi_index([[3], [3]], heatmap.shape)
print(index)
>>> [21]
[/code]