CODE EXAMPLE FOR PYTHON

how to input a string character into a numpy zeros imatrix n python

a = np.zeros((3,3),int)
a[[0,1,2],[2,0,1]] = [1,2,3]
a
array([[0, 0, 1],
       [2, 0, 0],
       [0, 3, 0]])

A = a.astype(str)
A
array([['0', '0', '1'],
       ['2', '0', '0'],
       ['0', '3', '0']],
      dtype='<U11')

A[[0,1,2],[0,1,2]] = 'X'
A 
array([['X', '0', '1'],
       ['2', 'X', '0'],
       ['0', '3', 'X']],
      dtype='<U11')