Create a 5 by 5 matrix with 5 ones randomly distributed

April 21, 2022

Here is the code I have tried. How can I modify it if we just want 5 ones randomly distributed in it?

import numpy as np
mat = np.random.randint(2,size=(5,5))

>Solution :

>>> import numpy as np
>>> import random
>>> mat = np.zeros(5*5)
>>> indices = random.sample(range(5*5), 5)
>>> mat[indices] = 1
>>> mat = mat.reshape(5, 5)
>>> mat
array([[0., 0., 0., 0., 0.],
       [0., 0., 0., 0., 1.],
       [0., 0., 1., 0., 0.],
       [1., 0., 1., 0., 1.],
       [0., 0., 0., 0., 0.]])

I’ve explicitly used 5*5. You can put 25 there, or N*M or similar.

You could also use the NumPy random module, but the Python stdlib random module is easy enough to use here.