kableExtra (version 1.4.0)

add_header_above: Add a header row on top of current header

Description

Tables with multiple rows of header rows are extremely useful to demonstrate grouped data. This function takes the output of a kable() function and adds an header row on top of it.

Usage

add_header_above(
  kable_input,
  header = NULL,
  bold = FALSE,
  italic = FALSE,
  monospace = FALSE,
  underline = FALSE,
  strikeout = FALSE,
  align = "c",
  color = NULL,
  background = NULL,
  font_size = NULL,
  angle = NULL,
  escape = TRUE,
  line = TRUE,
  line_sep = 3,
  extra_css = NULL,
  include_empty = FALSE,
  border_left = FALSE,
  border_right = FALSE
)

Arguments

kable_input

Output of knitr::kable() with format specified

header

A (named) character vector with colspan as values. For example, c(" " = 1, "title" = 2) can be used to create a new header row for a 3-column table with "title" spanning across column 2 and 3. For convenience, when colspan equals to 1, users can drop the = 1 part. As a result, c(" ", "title" = 2) is the same as c(" " = 1, "title" = 2). Alternatively, a data frame with two columns can be provided: The first column should contain the header names (character vector) and the second column should contain the colspan (numeric vector). This input can be used if there are problems with Unicode characters in the headers.

bold

A T/F value to control whether the text should be bolded.

italic

A T/F value to control whether the text should to be emphasized.

monospace

A T/F value to control whether the text of the selected column need to be monospaced (verbatim)

underline

A T/F value to control whether the text of the selected row need to be underlined

strikeout

A T/F value to control whether the text of the selected row need to be struck out.

align

A character string for cell alignment. For HTML, possible values could be l, c, r plus left, center, right, justify, initial and inherit while for LaTeX, you can only choose from l, c & r.

color

A character string/vector for text color. Here please pay attention to the differences in color codes between HTML and LaTeX.

background

A character string/vector for background color. Here please pay attention to the differences in color codes between HTML and LaTeX. Also note that in HTML, background defined in cell_spec won't cover the whole cell.

font_size

A numeric input/vector for font size. For HTML, you can also use options including xx-small, x-small, small, medium, large, x-large, xx-large, smaller, larger, initial and inherit.

angle

0-360, degree that the text will rotate.

escape

A T/F value showing whether special characters should be escaped.

line

A T/F value to control whether a line will appear underneath the header

line_sep

A numeric value indicating how much the midlines should be separated by space. Default is 3.

extra_css

An HTML only option. CSS defined here will be send to the td cell.

include_empty

Whether empty cells in HTML should also be styled. Default is FALSE.

border_left

T/F option for border on the left side in latex.

border_right

T/F option for border on the right side in latex.

Examples

if (FALSE) {
x <- knitr::kable(head(mtcars), "html")
# Add a row of header with 3 columns on the top of the table. The column
# span for the 2nd and 3rd one are 5 & 6.
add_header_above(x, c(" ", "Group 1" = 5, "Group 2" = 6))
}