title: How to read file with mixed data type into a numpy array in Python?
body: <p>How to read file with mixed data type into a numpy array in Python?</p>
  
  <p>I'm a new python learner. I'm trying to read an existing file with mixed data type into a numpy array.</p>
  
  <p>The content of file data.txt (if comma is not a good symbol, it can be replaced by space):</p>
  
  <pre><code>   ,'A','B','C','D'
  'A',  0,  3,  5, -1
  'B',  3,  0,  1,  6
  'C',  5,  1,  0,  2
  'D', -1,  6,  2,  0
  </code></pre>
  
  <p>The expected output numpy array is as follows:</p>
  
  <pre><code>array([[None,'A','B','C','D'],
         ['A',  0,  3,  5, -1 ],
         ['B',  3,  0,  1,  6 ],
         ['C',  5,  1,  0,  2 ],
         ['D', -1,  6,  2,  0 ]])
  </code></pre>