R Markdown and Quarto

Use flextable in R Markdown and Quarto documents with automatic format detection, captions, and chunk options.

flextable integrates with knitr through knit_print.flextable(), which is called automatically when a flextable object appears in a code chunk. You do not need to call it directly.

How rendering works

When knitr processes a chunk containing a flextable, it detects the output format and generates the appropriate output:

Output format	Rendering method
HTML	Native HTML table with scoped CSS
Word (docx)	Office Open XML (wml)
PDF	LaTeX table code
PowerPoint (pptx)	Presentation ML (pml)
Other (GitHub, Beamer, etc.)	PNG image via save_as_image()

No special setup is required. Place a flextable object in a chunk and it renders:

library(flextable)

ft <- flextable(head(iris))
ft <- autofit(ft)
ft

Adding captions

The recommended way to add a caption is with set_caption():

ft <- flextable(head(airquality))
ft <- set_caption(ft, caption = "Daily air quality measurements")
ft

When set_caption() is used, chunk options related to captions are ignored.

In Quarto, use tbl-cap and label chunk options instead of set_caption():

```{r}
#| label: tbl-airquality
#| tbl-cap: "Daily air quality measurements"
ft
```

Cross-references in Quarto use @tbl-airquality. In bookdown documents, cross-references use \@ref(tab:chunk_label).

Chunk options reference

All formats

Option	Description	Default
ft.align	Table alignment: 'left', 'center', 'right'	'center'

R Markdown captions

These options are only used when set_caption() has not been called on the table:

Option	Description	Default
tab.cap	Caption text	NULL
tab.id	Caption id / bookmark	NULL
tab.topcaption	Place caption above the table	TRUE
tab.lp	Caption sequence identifier	"tab:"
tab.cap.style	Word paragraph style for the caption	NULL

HTML

Option	Description	Default
ft.htmlscroll	Enable horizontal scrolling	FALSE

Word

Option	Description	Default
ft.split	Allow rows to break across pages	TRUE

PDF

Option	Description	Default
ft.tabcolsep	Space between text and cell borders (pt)	0
ft.arraystretch	Row height multiplier	1.5
ft.latex.float	Float placement: 'none', 'float', 'wrap-r', 'wrap-l', 'wrap-i', 'wrap-o'	'none'

PowerPoint

Option	Description	Default
ft.left	Left position of table placeholder (inches)	1
ft.top	Top position of table placeholder (inches)	2

Set defaults for an entire document with knitr::opts_chunk$set():

knitr::opts_chunk$set(
  ft.align = "left",
  ft.tabcolsep = 4
)

officedown caption options

When using officedown::rdocx_document(), additional caption chunk options become available:

Option	Description	Default
tab.cap.pre	Numbering prefix	"Table "
tab.cap.sep	Numbering suffix	": "
tab.cap.tnd	Title number depth	0
tab.cap.fp_text	Caption prefix formatting	fp_text_lite(bold=TRUE)
tab.cap.tns	Title / table number separator	"-"

Tables inside loops

To print flextable objects inside for loops or if statements, use flextable_to_rmd(). Set the chunk option results = 'asis':

```{r results='asis'}
for (species in unique(iris$Species)) {
  sub <- subset(iris, Species == species)
  ft <- flextable(head(sub))
  ft <- set_caption(ft, caption = as.character(species))
  flextable_to_rmd(ft)
}
```

Automatic data frame conversion

use_df_printer() replaces the default data frame print method so that any data frame printed in a document is automatically converted to a flextable:

use_df_printer()

# now data frames render as flextable
head(iris)

Call use_model_printer() to do the same for model objects. These functions are best placed in a setup chunk.

Quarto setup with use_flextable_qmd()

The flextable-qmd Lua filter extension allows Quarto markdown syntax inside flextable cells: cross-references, bold, italic, links, math, inline code, and shortcodes. Install it with:

use_flextable_qmd()

After installing, use as_qmd() to mark cell content as Quarto markdown:

ft <- flextable(data.frame(
  label = c("See @tbl-summary for details"),
  value = c(42)
))
ft <- compose(
  ft, j = "label",
  value = as_paragraph(as_qmd("See @tbl-summary for details"))
)

Post-processing hooks

set_flextable_defaults() accepts post-processing functions that are applied to every table before rendering. This is useful for applying consistent styling across a document:

set_flextable_defaults(
  post_process_html = function(ft) {
    theme_vanilla(ft)
  },
  post_process_docx = function(ft) {
    theme_booktabs(ft)
  }
)

Available hooks: post_process_all, post_process_html, post_process_docx, post_process_pdf, post_process_pptx.