How to make vertical scrollbar appear in RMarkdown code chunks (html view)

Question

I\'ve found many examples outlining how to add horizontal scrollbars to R Markdown HTML output, including this specific example here. However, none that describe how to add

Answer 1

Adding onto @Martin Schmelzer's solution, I noticed there can be issues if echo = TRUE, or if your output is not much large in other parts of the document. To fix this issue just change:

height: 50vh !important;

to

max-height: 50vh !important;

Answer 2

The problem seems to be that you did not specify the height of the code chunk. Try this instead:

<style>
pre {
  white-space: pre !important;
  overflow-y: scroll !important;
  height: 50vh !important;
}
</style>

(For information about the unit vh check this)