Create a 5 by 5 matrix with 5 ones randomly distributed-CodePudding

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))

CodePudding user response：

>>> 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.

CodePudding user response：

Since sometime comments may contain excellent answers, but may be hidden from view (or deleted altogether), I'm putting here the solution provided by Michael Szczesny:

>>> mat = np.random.permutation(np.eye(5, dtype=int).ravel()).reshape(5,5)
>>> mat
array([[0, 0, 0, 0, 0],
       [0, 1, 0, 0, 0],
       [1, 1, 0, 0, 0],
       [0, 0, 1, 1, 0],
       [0, 0, 0, 0, 0]])