Divide one column in array by another numpy

Question

I am trying to get

[[ 4.    0.   0. ]
 [ 8.    0.  0.  ]]

out of this:

[[ 2.    0.5   0.  ]
 [ 2.    0.25  0.  ]]

So I want to divide the first column by the second one:

div = arr[:,0]/arr[:,1] but don't know what's the best way to reshape and add zeros to get the result.

Thanks in advance.

Answer 1

If you want to do it in place, you could do

a[:, 0] = a[:, 0] / a[:, 1]
a[:, 1] = 0

If not

b = np.zeros(6).reshape(2, 3)
b[:, 0] = (a[:, 0] / a[:, 1])