title: Combine rows based on ranges in a column
body: <p>I have a pretty large dataset where I have a column for time in seconds and I want to combine rows where the time is close (range: .1-.2 seconds apart) as a mean. </p>
  
  <p>Here is an example of how the data looks:</p>
  
  <pre><code>BPM seconds
  63.9 61.899
  63.9 61.902
  63.8 61.910
  62.1 130.94
  62.1 130.95
  61.8 211.59
  63.8 280.5
  60.3 290.4  
  </code></pre>
  
  <p>So I would want to combine the first 3 rows, then the 2 following after that, and the rest would stand alone. Meaning I would want the data to look like this:</p>
  
  <pre><code>BPM seconds
  63.9 61.904
  62.1 130.95
  61.8 211.59
  63.8 280.5
  60.3 290.4 
  </code></pre>