title: Excluding part of the R markdown (html_notebook) from the final html output
body: <p>I am writing a relatively long report using R Notebook that makes use of R markdown language which combines text and code in the same document and generates html output. </p>
  
  <p>I would like to be able to exclude some of the analysis (both text and R code) from showing in the final HTML. This is very useful if I want to create two versions of the report - a full/detailed version, as well as a shorter version with main graphs and conclusions.</p>
  
  <p>Obviously, I can create separate Rmd file for each type of report (or comment out pieces of the report that need to be excluded for the shorter version), but I was wondering if there is a more elegant way to do it.</p>
  
  <p>Something like this:</p>
  
  <pre><code>     if (Version == "full_text"){
  
                  Full analysis goes here 
  
                  ```{r}
                  R code goes here (could be multiple chunks)
                  ```
       }
       else {
                  The shorter version goes here 
                  ```{r}
                  R code goes here 
                  ```
      }
  </code></pre>