% Generated by roxygen2: do not edit by hand
% Please edit documentation in R/add_header_above.R
\name{add_header_above}
\alias{add_header_above}
\title{Add a header row on top of current header}
\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)
}
\arguments{
\item{kable_input}{Output of \code{knitr::kable()} with \code{format} specified}

\item{header}{A (named) character vector with \code{colspan} as values. For
example, \code{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 \code{colspan} equals to 1, users can drop the \code{= 1} part.
As a result, \code{c(" ", "title" = 2)} is the same as \code{c(" " = 1, "title" = 2)}.}

\item{bold}{A T/F value to control whether the text should be bolded.}

\item{italic}{A T/F value to control whether the text should to be emphasized.}

\item{monospace}{A T/F value to control whether the text of the selected column
need to be monospaced (verbatim)}

\item{underline}{A T/F value to control whether the text of the selected row
need to be underlined}

\item{strikeout}{A T/F value to control whether the text of the selected row
need to be stricked out.}

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

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

\item{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.}

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

\item{angle}{0-360, degree that the text will rotate.}

\item{escape}{A T/F value showing whether special characters should be
escaped.}

\item{line}{A T/F value to control whether a line will appear underneath the
header}

\item{line_sep}{A numeric value indicating how much the midlines should be
separated by space. Default is 3.}

\item{extra_css}{An HTML only option. CSS defined here will be send to the
td cell.}
}
\description{
Tables with multiple rows of header rows are extremely useful
to demonstrate grouped data. This function takes the output of a \code{kable()}
function and adds an header row on top of it.
}
\examples{
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))

}