rewrapping kable latex table to different tabular environment

Question

I would like to keep just the "inside" lines of a latex table created by kable. I only know cumbersome and ugly ways to do so...attempts at cleaner versions failed. here is one clean flunk:

kable.rewrap <- function( df, newname= "mytable" ) {
    kt <- kable( df, "latex", booktabs=T )
    notop <- strsplit(kt, "\\midrule")[[1]][2]
    nosur <- strsplit(notop, "\\bottomrule" )[[1]][1]  ## fails: doesn't like "\\"!
    newkt <- paste0("\\begin{", newname, "}", nosur, "\n\\end{",newname,"}\n")
    ## attr(newkt, "format") <-  chr "latex"  # wrong
    newkt
}

print(kable.rewrap( data.frame( x=1:3, y=1:3 ), "mytable" ))

should produce

\begin{mytable}
\toprule
x & y\\
\midrule
1 & 1\\
2 & 2\\
3 & 3\\
\bottomrule
\end{mytable}

obviously, my latex code should define an environment mytable now. I am also puzzled by "bottomrule" in the nosur line works, but "\\bottomrule" fails.

(another alternative is to forego kable altogether and just work with the data frame, separating each line by a \ and each column by a &.)

advice appreciated.

Answer 1

1) The kable.envir argument will add the mytable part but that still causes tabulars to be generated which we remove using gsub:

kable(test_data, "latex", booktabs = TRUE, table.envir = "mytable") %>%
  gsub(".(begin|end){tabular.*}", "", ., perl = TRUE)

giving:

\begin{mytable}


\toprule
x & y\\
\midrule
1 & 1\\
2 & 2\\
3 & 3\\
\bottomrule

\end{mytable}

2) Another possibility is to define your own mytabular environment and then use:

kable(test_data, "latex", booktabs = TRUE, table.envir = "mytable") %>%
  kable_styling(latex_table_env = "mytabular")

which gives:

\begin{mytable}

\begin{mytabular}{rr}
\toprule
x & y\\
\midrule
1 & 1\\
2 & 2\\
3 & 3\\
\bottomrule
\end{mytabular}
\end{mytable}

Added

In (2) rather than defining a do-nothing environment to replace tabular tex/latex actually makes one available already, namely @empty.

kable(test_data, "latex", booktabs = TRUE, table.envir = "mytable") %>%
  kable_styling(latex_table_env = "@empty")

Note

We named the data frame shown in the question as follows:

test_data <- data.frame(x = 1:3, y = 1:3)