The {gtsummary} package was written to be a companion to the {gt} package from RStudio. But not all output types are supported by the {gt} package. Therefore, we have made it possible to print {gtsummary} tables with various engines.

Output Types

Here’s a summary of the various R Markdown output types and the print engines that support them.

Print Engine Function HTML PDF RTF Word

gt

Key
Output fully supported
Formatted output, but missing indentation, footnotes, spanning headers
No formatted output
Output not supported
Under development

Any {gtsummary} table can be converted to one of the types in the table above. For example, the code below prints a {gtsummary} table as a {flextable} table, instead of the default {gt} table.

Default Printer

Tables printed with {gtsummary} can be seamlessly integrated into R markdown documents. Currently, {gt} supports HTML output, with LaTeX and RTF planned for the future. The table below summarizes the default print engine utilized for {gtsummary} tables for various R Markdown output formats.

Output Type Default Engine Details

HTML

{gt}

{gt} output is fully supported with HTML output.

PDF

kable

You may force printing with {gt} by converting a {gtsummary} object to {gt} with as_gt(), e.g. tbl_summary(trial) %>% as_gt(). PDF output is under development in the {gt} package. You may get a gorgeous table, but you may also get an error or a malformed table.

RTF

kable

You may force printing with {gt} by converting a {gtsummary} object to {gt} with as_gt(), e.g. tbl_summary(trial) %>% as_gt(). RTF output is under development in the {gt} package. You may get a gorgeous table, but you may also get an error or a malformed table.

Word

flextable

{flextable} is the default print engine for Word output, as {gt} does not support Word. If {flextable} is not installed, kable is used.

When a table is printed with knitr::kable() the resulting table is less full featured compared to a table printed with {gt}. For example, the table will not contain footnotes, spanning headers, or row indentation.

Example R Markdown Report

An example R markdown report using {gtsummary} has been included with the package. To open the example file, run the following command in the R console.

library(gtsummary)
system.file(package = "gtsummary") %>%
  file.path("rmarkdown_example/gtsummary_rmarkdown_html.Rmd") %>%
  file.edit()

LaTeX

To print {gtsummary} tables using LaTeX, utilize one of the supporting print engines.

# build gtsummary table
tbl <- tbl_summary(trial)

# using the {gt} package
as_gt(tbl) %>% gt::as_latex()

# using the {huxtable} package
as_hux_table(tbl) %>% huxtable::to_latex()

# using the {kableExtra} package
as_kable_extra(tbl, format = "latex")

# using the knitr::kable function
as_kable(tbl, format = "latex")

Images

Use the {gt} package’s gt::gtsave() function to save images of {gtsummary} tables.

tbl_summary(trial) %>%    # build gtsummary table
  as_gt() %>%             # convert to gt table
  gt::gtsave(             # save table as image
    filename = "my_table_image.png"
  )

Tips

When printing {gt} or {gtsummary} tables in a loop, use print() and results = 'asis' in the R markdown chunk.

```{r loop_print, results = 'asis'}
for (i in 1) {
  tbl <- tbl_summary(trial)   # build gtsummary table
  print(tbl)                  # print table
}
```

If print(tbl) does not work for you, try either knitr::knit_print(tbl) or cat(knitr::knit_print(tbl)).

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