title: Clear the current output from entire RMarkdown (Rmd) document in RStudio?
body: <p>Especially when working with long RMarkdowns (e.g. 2-3000+ lines), it is desirable to completely clear all rendering and output (i.e. to get back to the same state as though none of the code in the RMarkdown had ever been executed), except <em>without</em> necessarily clearing the environment.</p>
  <p>Is there a way to do this?</p>
  <p>Note: in case someone wonders why, here are a couple of reasons:</p>
  <ol>
  <li>occasionally (especially with javascript-heavy renderings, e.g. plotly, wordcloud etc) there can occasionally be bugs which not only affect the rendering that contains the bug, but all other renderings in the document, and</li>
  <li>particularly in long Rmd files, it is sometimes simply easier to scroll through a doc which hasn't got renderings in it.</li>
  </ol>