How to 'zero' out rows & columns in an array

Question

I have a 2D array to represent a many-many mapping :

0   3   1   3
3   0   0   0
1   0   0   0
3   0   0   0

What is the quickest way to 'zero' out rows and column entries corresponding to a particular index in this array?

Answer 1

arr[i] = 0   # zeroes out row i
arr[:,i] = 0 # zeroes out column i