title: Python Insert Matrix into another Matrix
body: <p>What I want to do is to insert a matrix (of str) in an other matrix.</p>
  
  <pre><code>HM = 
  [['', '', '', '', ''],
   ['', '', '', '', ''],
   ['', '', '', '', ''],
   ['', '', '', '', ''],
   ['', '', '', '', ''],
   ['', '', '', '', ''],
   ['', '', '', '', '']]
  B = [["AA", "BB"],["CC","DD"]]
  offset = (1,2)
  </code></pre>
  
  <p>The result should be:</p>
  
  <pre><code>[['', '', '', '', ''],
   ['', '', 'AA', 'BB', ''],
   ['', '', 'CC', 'DD', ''],
   ['', '', '', '', ''],
   ['', '', '', '', ''],
   ['', '', '', '', ''],
   ['', '', '', '', '']]
  </code></pre>
  
  <p>working on jupyter notebook version 3.7, tried np.insert, tried HM + B, tried np slash</p>
  
  <pre><code>HM = [[""]*15]*10
  B = [["BBB"]*3, ["CCC"]*3, ["DDD"]*3]
  offsetx = 2
  offsety = 1
  for x in range(1, 1 + offsetx):
      for y in range(2, 2 + offsety):
          HM[x][y] = B[x][y] 
  HM
  </code></pre>