kableExtra R Package Documentation

kableExtra is not a standalone table generator. Instead, it is an extension package designed to add features to the output of knitr::kable() (or the kbl() alternative) using the R pipe operator (%>%).

Key concepts:

• Pipable syntax: You chain kableExtra functions onto a table object to layer styling and structural elements.
• Unified functions: Most functions are format-agnostic. They detect whether you are rendering to HTML or LaTeX (based on the format specified in kable() or the global knitr.table.format option) and apply the appropriate styling automatically.
• kbl() function: A recommended alternative to kable() that provides better documentation and improved format detection.

library(kableExtra)
dt <- mtcars[1:5, 1:4]

# Example of the pipable pattern
kbl(dt) %>%
  kable_styling(bootstrap_options = "striped") %>%
  footnote(c("table footnote"))

To ensure tables look good across different output formats, you must combine universal kable and kableExtra API calls with format-specific settings.

Key considerations:

• Universal API: Most styling functions work similarly for both HTML and LaTeX.
• Format-specific settings:
  • Use booktabs = T and longtable settings within kable() for LaTeX.
  • Use bootstrap_options (for HTML) and latex_options (for LaTeX) within kable_styling().
• EPUB Support: If you need to output tables in .epub, ensure you are using the development version or version 1.0 on CRAN, as older versions (below 0.9.0) may not support it.

library(kableExtra)
library(dplyr)

# Example of a cross-format compatible table
options(kableExtra.html.bsTable = T)
iris[1:10, ] %>%
  mutate_if(is.numeric, function(x) {
    cell_spec(x, bold = T, 
              color = spec_color(x, end = 0.9), 
              font_size = spec_font_size(x))
  }) %>%
  mutate(Species = cell_spec(
    Species, color = "white", bold = T,
    background = spec_color(1:10, end = 0.9, 
                            option = "A", direction = -1)
  )) %>%
  kable(escape = F, align = "c", booktabs = T) %>%
  kable_styling(c("striped", "condensed"), 
                latex_options = "striped", 
                full_width = F)

When using bookdown to create Gitbooks, rmarkdown does not load bootstrap by default. To enable Bootstrap styling for your kableExtra tables, you must set the kableExtra.html.bsTable option to TRUE.

Important: Gitbook's default table CSS can conflict with Bootstrap (e.g., preventing the hover effect from working). To resolve this, ensure you are using bookdown version 0.7.21 or later and disable the default table CSS in your _output.yml file.

Steps to enable Bootstrap in Gitbook:

1. Set the kableExtra option in your R script.
2. Disable table_css in your _output.yml configuration.

library(kableExtra)
options(kableExtra.html.bsTable = T)

mtcars[1:5, 1:5] %>%
  kable(booktabs = T) %>%
  kable_styling(
    bootstrap_options = c("striped","hover", "bordered", "condensed"),
    latex_options = c("striped")
  ) %>%
  column_spec(1, color = "red") %>%
  add_header_above(c(" ", "Group A" = 2, "Group B" = 3))

Configure _output.yml for Gitbook

bookdown::gitbook:
  table_css: false