title: how to get a continuous rolling mean in pandas?
body: <p>Looking to get a continuous rolling mean of a dataframe. </p>
  
  <p>df looks like this </p>
  
  <pre><code>index price
  
  0      4
  1      6
  2      10
  3      12
  </code></pre>
  
  <p>looking to get a continuous rolling of price</p>
  
  <p>the goal is to have it look this a moving mean of all the prices.</p>
  
  <pre><code>index price  mean
  
  0      4      4
  1      6      5
  2      10     6.67
  3      12     8 
  </code></pre>
  
  <p>thank you in advance!</p>