title: Matrix entered by user
body: <p>I want to create a matrix of 3x3, with random entries (among 0, 1, 2, 3, 4, 5) that the user is going to give (he'll have to press 'Enter' to start, but my code doesn't run. Here it is: </p>
  
  <pre><code>import math
  line = ' '.join(map(str, range(4*4))) # Take input from user
  '0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15'
  items = map(int, line.split()) # convert str to int
  [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15]
  3 = int(math.sqrt(len(items))) # len(items) should be n**2
  4
  matrix = [ items[i*3:(i+1)*3] for i in range(3) ]
  [[0, 1, 2, 3], [4, 5, 6, 7], [8, 9, 10, 11], [12, 13, 14, 15]]
  </code></pre>