group_rows: Put a few rows of a table into one category
In kableExtra: Construct Complex Table with 'kable' and Pipe Syntax

Group a few rows in a table together under a label.

group_rows(
  kable_input,
  group_label = NULL,
  start_row = NULL,
  end_row = NULL,
  index = NULL,
  label_row_css = "border-bottom: 1px solid;",
  latex_gap_space = "0.3em",
  escape = TRUE,
  latex_align = "l",
  latex_wrap_text = FALSE,
  colnum = NULL,
  bold = TRUE,
  italic = FALSE,
  hline_before = FALSE,
  hline_after = FALSE,
  extra_latex_after = NULL,
  indent = TRUE,
  monospace = FALSE,
  underline = FALSE,
  strikeout = FALSE,
  color = NULL,
  background = NULL
)

pack_rows(
  kable_input,
  group_label = NULL,
  start_row = NULL,
  end_row = NULL,
  index = NULL,
  label_row_css = "border-bottom: 1px solid;",
  latex_gap_space = "0.3em",
  escape = TRUE,
  latex_align = "l",
  latex_wrap_text = FALSE,
  colnum = NULL,
  bold = TRUE,
  italic = FALSE,
  hline_before = FALSE,
  hline_after = FALSE,
  extra_latex_after = NULL,
  indent = TRUE,
  monospace = FALSE,
  underline = FALSE,
  strikeout = FALSE,
  color = NULL,
  background = NULL
)

`kable_input`	Output of `knitr::kable()` with `format` specified
`group_label`	A character string for the name of the group
`start_row`	A numeric value that tells the function in which row the group starts. Note that the counting excludes header rows and other group labeling rows
`end_row`	A numeric value that tells the function in which row the group ends.
`index`	A named vector providing the index for robust row-grouping tasks. Basically, you can use it in the same way as `add_header_above()`.
`label_row_css`	A character string for any customized css used for the labeling row. By default, the labeling row will have a solid black line underneath. Only useful for HTML documents.
`latex_gap_space`	A character value telling LaTeX how large the gap between the previous row and the group labeling row. Only useful for LaTeX documents.
`escape`	A T/F value showing whether special characters should be escaped.
`latex_align`	Adjust justification of group_label in latex only. Value should be "c" for centered on row, "r" for right justification, or "l" for left justification. Default Value is "l" If using html, the alignment can be set by using the label_row_css parameter.
`latex_wrap_text`	T/F for wrapping long text. Default is off. Whenever it is turned on, the table will take up the entire line. It's recommended to use this with full_width in kable_styling.
`colnum`	A numeric that determines how many columns the text should span. The default setting will have the text span the entire length.
`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.
`hline_before`	A T/F value that addes a horizontal line before the group_row label. Default value is False.
`hline_after`	A replicate of `hline.after` in xtable. It addes a hline after the row
`extra_latex_after`	Extra LaTeX text to be added after the row.
`indent`	A T/F value to control whether list items are indented.
`monospace`	T/F value to control whether the text of the selected column need to be monospaced (verbatim)
`underline`	T/F value to control whether the text of the selected row need to be underlined
`strikeout`	T/F value to control whether the text of the selected row need to be striked out.
`color`	A character string for column text color. Here please pay attention to the differences in color codes between HTML and LaTeX.
`background`	A character string for column background color. Here please pay attention to the differences in color codes between HTML and LaTeX.

## Not run: 
x <- knitr::kable(head(mtcars), "html")
# Put Row 2 to Row 5 into a Group and label it as "Group A"
pack_rows(x, "Group A", 2, 5)

## End(Not run)