title: Create sequential counting in data frame column
body: <p>Let's say I have a data frame looking like this:</p>
  
  <pre><code>Value1   Value2
  1        543
  1        845
  3        435
  5        724
  5        234
  8        204
  </code></pre>
  
  <p>Now, I would like the first column to count up sequentially, instead of jumping several steps every time the value changes, like so:</p>
  
  <pre><code>Value1   Value2
  1        543
  1        845
  2        435
  3        724
  3        234
  4        204
  </code></pre>
  
  <p>If there was some way of simply replacing an element in a data frame with something else, this could be easily done. However, I don't know if there is such a command. Also, I guess some kind of macro command for doing something like this would do, but I guess there isn't such a command.</p>