title: correlation between arrays in python
body: <p>I have 2 arrays.</p>
  
  <pre><code> a1 = [1,2,4]
   a2 = [3,4,5]
  </code></pre>
  
  <p>how would I find the correlation between these 2 arrays using python. </p>
  
  <p>In matlab, you would do:</p>
  
  <pre><code>corr(a1,a2)
  </code></pre>
  
  <p>How to do this in python?</p>