title: How to divide a pandas dataframe into smaller dataframes, based on a column value?
body: <p><a href="https://i.stack.imgur.com/wot9W.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/wot9W.png" alt="enter image description here"></a></p>
  
  <p>I want my dataframe to get splitted into smaller dfs, based on 'z' value.
  In this case, 2 dfs as I only want to take whats between the zeros (z column).
  i.e. Dataframe1: 01/10/2018 0:30 - 1/10/2018 1:20
    AND
  Dataframe2: 01/10/2018 2:00 - 1/10/2018 2:40</p>
  
  <p>How can this be done in a loop for bigger datasets?
  Discarding the zeroes and only putting whats in between. </p>