Please see the package documentation site for how to use it in LaTeX.

Overview

The goal of kableExtra is to help you build common complex tables and manipulate table styles. It imports the pipe %>% symbol from magrittr and verbalize all the functions, so basically you can add “layers” to a kable output in a way that is similar with ggplot2 and plotly.

Installation

install.packages("kableExtra")

# For dev version
# install.packages("devtools")
devtools::install_github("haozhu233/kableExtra")

Getting Started

Here we are using the first few columns and rows from dataset mtcars

library(knitr)
library(kableExtra)
dt <- mtcars[1:5, 1:6]

When you are using kable(), if you don’t specify format, by default it will generate a markdown table and let pandoc handle the conversion from markdown to HTML/PDF. This is the most favorable approach to render most simple tables as it is format independent. If you switch from HTML to pdf, you basically don’t need to change anything in your code. However, markdown doesn’t support complex table. For example, if you want to have a double-row header table, markdown just cannot provide you the functionality you need. As a result, when you have such a need, you should define format in kable() as either “html” or “latex”. You can also define a global option at the beginning using options(knitr.table.format = "html") so you don’t repeat the step everytime.

options(knitr.table.format = "html") 
## If you don't define format here, you'll need put `format = "html"` in every kable function.

Basic HTML Table

Basic HTML output of kable looks very crude. To the end, it’s just a plain HTML table without any love from css.

kable(dt)
mpg cyl disp hp drat wt
Mazda RX4 21.0 6 160 110 3.90 2.620
Mazda RX4 Wag 21.0 6 160 110 3.90 2.875
Datsun 710 22.8 4 108 93 3.85 2.320
Hornet 4 Drive 21.4 6 258 110 3.08 3.215
Hornet Sportabout 18.7 8 360 175 3.15 3.440

Apply Bootstrap

When used on a HTML table, kable_styling() will automatically apply twitter bootstrap theme to the table. Now it should looks the same as the original pandoc output (the one when you don’t specify format in kable()) but this time, you are controlling it.

kable(dt) %>%
  kable_styling()
mpg cyl disp hp drat wt
Mazda RX4 21.0 6 160 110 3.90 2.620
Mazda RX4 Wag 21.0 6 160 110 3.90 2.875
Datsun 710 22.8 4 108 93 3.85 2.320
Hornet 4 Drive 21.4 6 258 110 3.08 3.215
Hornet Sportabout 18.7 8 360 175 3.15 3.440

Table Styles

kable_styling offers server other ways to customize the look of a HTML table.

Bootstrap Options

If you are familiar with twitter bootstrap, you probably have already known its predefined classes, including striped, bordered, hover, condensed and responsive. If you are not familiar, no worries, you can take a look at their documentation site to get a sense of how they look like. All of these options are available here.

For example, to add striped lines (alternative row colors) to your table and you want to highlight the hovered row, you can simply type:

kable(dt) %>%
  kable_styling(bootstrap_options = c("striped", "hover"))
mpg cyl disp hp drat wt
Mazda RX4 21.0 6 160 110 3.90 2.620
Mazda RX4 Wag 21.0 6 160 110 3.90 2.875
Datsun 710 22.8 4 108 93 3.85 2.320
Hornet 4 Drive 21.4 6 258 110 3.08 3.215
Hornet Sportabout 18.7 8 360 175 3.15 3.440

The option condensed can also be handy in many cases when you don’t want your table to be too large. It has slightly shorter row height.

kable(dt) %>%
  kable_styling(bootstrap_options = c("striped", "hover", "condensed"))
mpg cyl disp hp drat wt
Mazda RX4 21.0 6 160 110 3.90 2.620
Mazda RX4 Wag 21.0 6 160 110 3.90 2.875
Datsun 710 22.8 4 108 93 3.85 2.320
Hornet 4 Drive 21.4 6 258 110 3.08 3.215
Hornet Sportabout 18.7 8 360 175 3.15 3.440

Tables with option responsive looks the same with others on a large screen. However, on a small screen like phone, they are horizontally scrollable. Please resize your window to see the result.

kable(dt) %>%
  kable_styling(bootstrap_options = c("striped", "hover", "condensed", "responsive"))
mpg cyl disp hp drat wt
Mazda RX4 21.0 6 160 110 3.90 2.620
Mazda RX4 Wag 21.0 6 160 110 3.90 2.875
Datsun 710 22.8 4 108 93 3.85 2.320
Hornet 4 Drive 21.4 6 258 110 3.08 3.215
Hornet Sportabout 18.7 8 360 175 3.15 3.440

Full Width or Not?

By default, a bootstrap table takes 100% of the width. It is supposed to use together with its grid system to scale the table properly. However, when you are writing a rmarkdown document, you probably don’t want to write your own css/or grid. For some small tables with only few columns, a page wide table looks awful. To make it easier, you can specify whether you want the table to have full_width or not in kable_styling. By default, full_width is set to be TRUE for HTML tables (note that for LaTeX, the default is FALSE since I don’t want to change the “common” looks unless you specified it.)

kable(dt) %>%
  kable_styling(bootstrap_options = "striped", full_width = F)
mpg cyl disp hp drat wt
Mazda RX4 21.0 6 160 110 3.90 2.620
Mazda RX4 Wag 21.0 6 160 110 3.90 2.875
Datsun 710 22.8 4 108 93 3.85 2.320
Hornet 4 Drive 21.4 6 258 110 3.08 3.215
Hornet Sportabout 18.7 8 360 175 3.15 3.440

Position

Table Position only matters when the table doesn’t have full_width. You can choose to align the table to center, left or right side of the page

kable(dt) %>%
  kable_styling(bootstrap_options = "striped", full_width = F, position = "left")
mpg cyl disp hp drat wt
Mazda RX4 21.0 6 160 110 3.90 2.620
Mazda RX4 Wag 21.0 6 160 110 3.90 2.875
Datsun 710 22.8 4 108 93 3.85 2.320
Hornet 4 Drive 21.4 6 258 110 3.08 3.215
Hornet Sportabout 18.7 8 360 175 3.15 3.440

Becides these three common options, you can also wrap text around the table using the float-left or float-right options.

kable(dt) %>%
  kable_styling(bootstrap_options = "striped", full_width = F, position = "float_right")
mpg cyl disp hp drat wt
Mazda RX4 21.0 6 160 110 3.90 2.620
Mazda RX4 Wag 21.0 6 160 110 3.90 2.875
Datsun 710 22.8 4 108 93 3.85 2.320
Hornet 4 Drive 21.4 6 258 110 3.08 3.215
Hornet Sportabout 18.7 8 360 175 3.15 3.440

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Cras sit amet mauris in ex ultricies elementum vel rutrum dolor. Phasellus tempor convallis dui, in hendrerit mauris placerat scelerisque. Maecenas a accumsan enim, a maximus velit. Pellentesque in risus eget est faucibus convallis nec at nulla. Phasellus nec lacinia justo. Morbi fermentum, orci id varius accumsan, nibh neque porttitor ipsum, consectetur luctus risus arcu ac ex. Aenean a luctus augue. Suspendisse et auctor nisl. Suspendisse cursus ultrices quam non vulputate. Phasellus et pharetra neque, vel feugiat erat. Sed feugiat elit at mauris commodo consequat. Sed congue lectus id mattis hendrerit. Mauris turpis nisl, congue eget velit sed, imperdiet convallis magna. Nam accumsan urna risus, non feugiat odio vehicula eget.

Font Size

If one of your tables is huge and you want to use a smaller font size for that specific table, you can use the font_size option.

kable(dt) %>%
  kable_styling(bootstrap_options = "striped", font_size = 7)
mpg cyl disp hp drat wt
Mazda RX4 21.0 6 160 110 3.90 2.620
Mazda RX4 Wag 21.0 6 160 110 3.90 2.875
Datsun 710 22.8 4 108 93 3.85 2.320
Hornet 4 Drive 21.4 6 258 110 3.08 3.215
Hornet Sportabout 18.7 8 360 175 3.15 3.440

Add Extra Header Rows

Tables with multi-row headers can be very useful to demonstrate grouped data. To do that, you can pipe your kable object into add_header_above(). The header variable is supposed to be a named character with the names as new column names and values as column span. For your convenience, if column span equals to 1, you can ignore the =1 part so the function below can be written as `add_header_above(c(" “,”Group 1" = 2, “Group 2” = 2, “Group 3” = 2)).

kable(dt) %>%
  kable_styling("striped") %>%
  add_header_above(c(" " = 1, "Group 1" = 2, "Group 2" = 2, "Group 3" = 2))
Group 1
Group 2
Group 3
mpg cyl disp hp drat wt
Mazda RX4 21.0 6 160 110 3.90 2.620
Mazda RX4 Wag 21.0 6 160 110 3.90 2.875
Datsun 710 22.8 4 108 93 3.85 2.320
Hornet 4 Drive 21.4 6 258 110 3.08 3.215
Hornet Sportabout 18.7 8 360 175 3.15 3.440

In fact, if you want to add another row of header on top, please feel free to do so.

kable(dt) %>%
  kable_styling(c("striped", "bordered")) %>%
  add_header_above(c(" ", "Group 1" = 2, "Group 2" = 2, "Group 3" = 2)) %>%
  add_header_above(c(" ", "Group 4" = 4, "Group 5" = 2)) %>%
  add_header_above(c(" ", "Group 6" = 6))
Group 6
Group 4
Group 5
Group 1
Group 2
Group 3
mpg cyl disp hp drat wt
Mazda RX4 21.0 6 160 110 3.90 2.620
Mazda RX4 Wag 21.0 6 160 110 3.90 2.875
Datsun 710 22.8 4 108 93 3.85 2.320
Hornet 4 Drive 21.4 6 258 110 3.08 3.215
Hornet Sportabout 18.7 8 360 175 3.15 3.440

Add footnote

Notation System

You can also use add_footnote() function from this package. You will need to supply a character vector with each element as one footnote. You may select from number, alphabet and symbol for different types of notations. Example are listed below.

Alphabet

kable(dt) %>%
  kable_styling("striped") %>%
  add_footnote(c("Footnote 1", "Have a good day."), notation = "alphabet")
mpg cyl disp hp drat wt
Mazda RX4 21.0 6 160 110 3.90 2.620
Mazda RX4 Wag 21.0 6 160 110 3.90 2.875
Datsun 710 22.8 4 108 93 3.85 2.320
Hornet 4 Drive 21.4 6 258 110 3.08 3.215
Hornet Sportabout 18.7 8 360 175 3.15 3.440

Number

kable(dt) %>%
  kable_styling("striped") %>%
  add_footnote(c("Footnote 1", "Have a good day."), notation = "number")
mpg cyl disp hp drat wt
Mazda RX4 21.0 6 160 110 3.90 2.620
Mazda RX4 Wag 21.0 6 160 110 3.90 2.875
Datsun 710 22.8 4 108 93 3.85 2.320
Hornet 4 Drive 21.4 6 258 110 3.08 3.215
Hornet Sportabout 18.7 8 360 175 3.15 3.440

Symbol

kable(dt) %>%
  kable_styling("striped") %>%
  add_footnote(c("Footnote 1", "Footnote 2", "Footnote 3"), notation = "symbol")
mpg cyl disp hp drat wt
Mazda RX4 21.0 6 160 110 3.90 2.620
Mazda RX4 Wag 21.0 6 160 110 3.90 2.875
Datsun 710 22.8 4 108 93 3.85 2.320
Hornet 4 Drive 21.4 6 258 110 3.08 3.215
Hornet Sportabout 18.7 8 360 175 3.15 3.440

In-table markers

By design, add_footnote() will transform any [note] to in-table footnote markers.

kable(dt, caption = "Demo Table[note]") %>%
  kable_styling("striped") %>%
  add_header_above(c(" ", "Group 1[note]" = 3, "Group 2[note]" = 3)) %>%
  add_footnote(c("This table is from mtcars", 
                 "Group 1 contains mpg, cyl and disp", 
                 "Group 2 contains hp, drat and wt"), 
               notation = "symbol")
Demo Table*
Group 1†
Group 2‡
mpg cyl disp hp drat wt
Mazda RX4 21.0 6 160 110 3.90 2.620
Mazda RX4 Wag 21.0 6 160 110 3.90 2.875
Datsun 710 22.8 4 108 93 3.85 2.320
Hornet 4 Drive 21.4 6 258 110 3.08 3.215
Hornet Sportabout 18.7 8 360 175 3.15 3.440

The following features are introduced in kableExtra 0.2.0.

Group Rows

Sometimes we want a few rows of the table being grouped together. They might be items under the same topic (e.g., animals in one species) or just different data groups for a categorical variable (e.g., age < 40, age > 40). With the new function group_rows() in kableExtra, this kind of task can be completed in one line. Please see the example below. Note that when you count for the start/end rows of the group, you don’t need to count for the header rows nor other group label rows. You only need to think about the row numbers in the “original R dataframe”.

kable(mtcars[1:10, 1:6], caption = "Group Rows") %>%
  kable_styling("striped", full_width = F) %>%
  group_rows("Group 1", 4, 7) %>%
  group_rows("Group 2", 8, 10)
Group Rows
mpg cyl disp hp drat wt
Mazda RX4 21.0 6 160.0 110 3.90 2.620
Mazda RX4 Wag 21.0 6 160.0 110 3.90 2.875
Datsun 710 22.8 4 108.0 93 3.85 2.320
Group 1
Hornet 4 Drive 21.4 6 258.0 110 3.08 3.215
Hornet Sportabout 18.7 8 360.0 175 3.15 3.440
Valiant 18.1 6 225.0 105 2.76 3.460
Duster 360 14.3 8 360.0 245 3.21 3.570
Group 2
Merc 240D 24.4 4 146.7 62 3.69 3.190
Merc 230 22.8 4 140.8 95 3.92 3.150
Merc 280 19.2 6 167.6 123 3.92 3.440

For advanced users, you can even define your own css for the group labeling.

kable(dt) %>%
  kable_styling("striped", full_width = F) %>%
  group_rows("Group 1", 3, 5, label_row_css = "background-color: #666; color: #fff;")
mpg cyl disp hp drat wt
Mazda RX4 21.0 6 160 110 3.90 2.620
Mazda RX4 Wag 21.0 6 160 110 3.90 2.875
Group 1
Datsun 710 22.8 4 108 93 3.85 2.320
Hornet 4 Drive 21.4 6 258 110 3.08 3.215
Hornet Sportabout 18.7 8 360 175 3.15 3.440

Add indentation

Unlike group_rows(), which will insert a labeling row, sometimes we want to list a few sub groups under a total one. In that case, add_indent() is probably more apporiate. For advanced users, you can even define your own css for the group labeling.

kable(dt) %>%
  kable_styling("striped", full_width = F) %>%
  add_indent(c(1, 3, 5))
mpg cyl disp hp drat wt
Mazda RX4 21.0 6 160 110 3.90 2.620
Mazda RX4 Wag 21.0 6 160 110 3.90 2.875
Datsun 710 22.8 4 108 93 3.85 2.320
Hornet 4 Drive 21.4 6 258 110 3.08 3.215
Hornet Sportabout 18.7 8 360 175 3.15 3.440

The following feature is introduced in kableExtra 0.2.1.

Column Style Specification

When you have a table with lots of explanatory texts, you may want to specified the column width for different column, since the auto adjust in HTML may not work in its best way while basic LaTeX table is really bad at handling text wrapping. Also, sometimes, you may want to highlight a column (e.g. a “Total” column) by making it bold. In these scenario, you can use column_spec(). You can find an example below.

Warning: If you have a super long table, you should be cautious when you use column_spec as the xml node modification takes time.

text_tbl <- data.frame(
  Items = c("Item 1", "Item 2", "Item 3"),
  Features = c(
    "Lorem ipsum dolor sit amet, consectetur adipiscing elit. Proin vehicula tempor ex. Morbi malesuada sagittis turpis, at venenatis nisl luctus a. ",
    "In eu urna at magna luctus rhoncus quis in nisl. Fusce in velit varius, posuere risus et, cursus augue. Duis eleifend aliquam ante, a aliquet ex tincidunt in. ", 
    "Vivamus venenatis egestas eros ut tempus. Vivamus id est nisi. Aliquam molestie erat et sollicitudin venenatis. In ac lacus at velit scelerisque mattis. "
  )
)

kable(text_tbl) %>%
  kable_styling(full_width = F) %>%
  column_spec(1, bold = T) %>%
  column_spec(2, width = "30em")
Items Features
Item 1 Lorem ipsum dolor sit amet, consectetur adipiscing elit. Proin vehicula tempor ex. Morbi malesuada sagittis turpis, at venenatis nisl luctus a.
Item 2 In eu urna at magna luctus rhoncus quis in nisl. Fusce in velit varius, posuere risus et, cursus augue. Duis eleifend aliquam ante, a aliquet ex tincidunt in.
Item 3 Vivamus venenatis egestas eros ut tempus. Vivamus id est nisi. Aliquam molestie erat et sollicitudin venenatis. In ac lacus at velit scelerisque mattis.

The following features are introduced in kableExtra 0.3.0

Row Style Specification

Similar with column_spec, you can define specifications for rows. Currently, you can either bold or italiciz an entire row. Note that, similar with other row-related functions in kableExtra, for the position of the target row, you don’t need to count in header rows or the group labelling rows.

kable(dt) %>%
  kable_styling("striped", full_width = F) %>%
  column_spec(7, bold = T) %>%
  row_spec(5, bold = T)
mpg cyl disp hp drat wt
Mazda RX4 21.0 6 160 110 3.90 2.620
Mazda RX4 Wag 21.0 6 160 110 3.90 2.875
Datsun 710 22.8 4 108 93 3.85 2.320
Hornet 4 Drive 21.4 6 258 110 3.08 3.215
Hornet Sportabout 18.7 8 360 175 3.15 3.440

Collapse Rows in Selected Columns

Function group_rows is great for showing simple structural information on rows but sometimes people may need to show structural information with multiple layers. When it happens, you may consider to use collapse_rows instead, which will put repeating cells in columns into multi-row cells.

collapse_rows_dt <- data.frame(C1 = c(rep("a", 10), rep("b", 5)),
                 C2 = c(rep("c", 7), rep("d", 3), rep("c", 2), rep("d", 3)),
                 C3 = 1:15,
                 C4 = sample(c(0,1), 15, replace = TRUE))
kable(collapse_rows_dt, "html", align = "c") %>%
  kable_styling(full_width = F) %>%
  column_spec(1, bold=T) %>%
  collapse_rows(columns = 1:2)
C1 C2 C3 C4
a c 1 1
2 1
3 1
4 1
5 0
6 1
7 1
d 8 1
9 1
10 1
b c 11 1
12 0
d 13 1
14 0
15 1