title: Save vectors to file in Python with NumPy
body: <p>I have a variable with a numeric value, a variable with a string value, and two vectors defined with NumPy</p>
  
  <pre><code>a = 10
  b = "text string"
  positions = np.array([])
  forces = np.array([])
  </code></pre>
  
  <p>I want to save these values to a file. I've used <a href="http://docs.scipy.org/doc/numpy/reference/generated/numpy.savetxt.html" rel="nofollow">http://docs.scipy.org/doc/numpy/reference/generated/numpy.savetxt.html</a> to save the two vectors with</p>
  
  <pre><code>np.savetxt('test.out', (positions,forces))
  </code></pre>
  
  <p>but I also need to store the values of <code>a</code> and <code>b</code>.</p>
  
  <p>How is this possible?</p>