Is there a way to add a scroll bar to dfSummary output in R markdown file?

I've already tried using the print function:

print(dfSummary(df), method = "render")

And also all the solutions here but they don't seem to work with html_document as the output file type of the R Markdown.

Olá, Inês

The answer is in provided link. You just need to add max.tbl.height argument and specify height in pixels:

print(dfSummary(df),
      max.tbl.height = 250,
      method = "render")

Here goes an reproducible example (see # comments for tips & tricks):

---
title: "Title"
author: "Author"
date: "26/05/2020"
output: 
  html_document:
    toc: TRUE
    toc_float: TRUE
---

```{r setup, include = FALSE}
library(knitr)
library(summarytools)
knitr::opts_chunk$set(results = "asis")
```

### Adding a scrollbar to dfSummary

```{r summarytools-css, echo = FALSE}
# with summarytools’ CSS we can cancel Bootstrap’s CSS (both are included by default)
# without it odd layout are expected, especially with dfSummary()
st_css(bootstrap = FALSE)
```

```{r dfSummary, echo = FALSE}
print(dfSummary(tobacco, 
                style = "grid",           # set style to “grid”
                valid.col = FALSE,        # drop Valid column if redundant
                graph.magnif = 0.82),     # zoom factor (max = 1) for bar plots and histograms
      headings = FALSE,
      footnote = NA,
      # use maximum table (specified) height (in pixels) and wrap the results in a scrollable window
      max.tbl.height = 300,            
      method = "render")
```

If you have interest, check out Dominic's vignette - "Recommendations for Using summarytools With Rmarkdown".