Adding multicolumns to my texreg output

Question

I want to make a table with grouped columns via texreg. I can only see options for grouped rows (groups).

Here's an example:

set.seed(01349)
DF <- data.frame(y = rnorm(100), x1A = rnorm(100), x2A = rnorm(100),
                 x1B = rnorm(100), x2B = rnorm(100))
regs <- lapply(paste0("x", 1:2, c("A", "A", "B", "B")), function(x)
          lm(paste0("y ~ ", x), data = DF))

Here's as close as I can get with plain texreg:

texreg(regs, custom.coef.names = c("Intercept", rep("x", 4)),
       custom.model.names = c("1", "2", "1", "2"))

With LaTeX output:

\begin{table}
\begin{center}
\begin{tabular}{l c c c c }
\hline
           & 1 & 2 & 1 & 2 \\
\hline
Intercept  & $-0.13$  & $-0.13$  & $-0.11$  & $-0.11$  \\
           & $(0.12)$ & $(0.12)$ & $(0.12)$ & $(0.12)$ \\
x          & $0.02$   & $0.07$   & $0.13$   & $-0.11$  \\
           & $(0.13)$ & $(0.12)$ & $(0.12)$ & $(0.13)$ \\
\hline
R$^2$      & 0.00     & 0.00     & 0.01     & 0.01     \\
Adj. R$^2$ & -0.01    & -0.01    & 0.00     & -0.00    \\
Num. obs.  & 100      & 100      & 100      & 100      \\
RMSE       & 1.18     & 1.17     & 1.17     & 1.17     \\
\hline
\multicolumn{5}{l}{\scriptsize{$^{***}p<0.001$, $^{**}p<0.01$, $^*p<0.05$}}
\end{tabular}
\caption{Statistical models}
\label{table:coefficients}
\end{center}
\end{table}

I'd prefer an extra line (highlighted with % comments):

\begin{table}
\begin{center}
\begin{tabular}{l c c c c }
\hline
%*************A HEADER LINE HERE*********************
 & \multicolumn{2}{c}{A} & \multicolumn{2}{c}{B} \\ %
%****************************************************
           & 1 & 2 & 1 & 2 \\
\hline
Intercept  & $-0.13$  & $-0.13$  & $-0.11$  & $-0.11$  \\
           & $(0.12)$ & $(0.12)$ & $(0.12)$ & $(0.12)$ \\
x          & $0.02$   & $0.07$   & $0.13$   & $-0.11$  \\
           & $(0.13)$ & $(0.12)$ & $(0.12)$ & $(0.13)$ \\
\hline
R$^2$      & 0.00     & 0.00     & 0.01     & 0.01     \\
Adj. R$^2$ & -0.01    & -0.01    & 0.00     & -0.00    \\
Num. obs.  & 100      & 100      & 100      & 100      \\
RMSE       & 1.18     & 1.17     & 1.17     & 1.17     \\
\hline
\multicolumn{5}{l}{\scriptsize{$^{***}p<0.001$, $^{**}p<0.01$, $^*p<0.05$}}
\end{tabular}
\caption{Statistical models}
\label{table:coefficients}
\end{center}
\end{table}

Am I missing something, or is there no built-in way to do this?

My workaround is:

x <- capture.output(texreg(
  regs, custom.coef.names = c("Intercept", rep("x", 4)),
  custom.model.names = c("1", "2", "1", "2")))

x[6] <- paste0("& \\multicolumn{2}{c}{A} & \\multicolumn{2}{c}{B} \\\\ \n", x[6])

cat(x, sep = "\n")

But that's obviously a bit duct-tape-y.

Answer 1

You can read code of the function by typing it into the console, or from the github website of the package texreg.

texreg
function (l, file = NULL, single.row = FALSE, stars = c(0.001, 
    0.01, 0.05), custom.model.names = NULL,...

This is the output of texreg for a table of 4 models:

\begin{table}
\begin{center}
\begin{tabular}{l c c c c }
\hline
 & Model 1 & Model 2 & Model 3 & Model 4 \\

I looked into the code line 469, the beginning of the table:

 string <- paste0(string, "\\begin{tabular}{", coldef, 
            "}", linesep)

Then I added some changes of my own:

string <- paste0(string, "\\begin{tabular}{", coldef, 
                 "}", linesep)
## Additions
string <- paste0(string, "\\\\[-1.8ex]\\hline", linesep)
string <- paste0(string, "& \\multicolumn{", length(l), 
                 "}{c}{\\textit{Dependent variable:}} \\\\", linesep)
string <- paste0(string, "\\cline{2-",length(modnames), "}", linesep)
string <- paste0(string, "\\\\[-1.8ex] & \\multicolumn{", length(l), 
                 "}{c}{", dep.var, "} \\\\", linesep)

Then, save the function with a different name for instance:

texreg2 <- function (l, file = NULL, single.row = FALSE, ...)

Now, the function requires internal functions from the package, so you need to attach your custom function to the namespace of the package in your environment. Easy peasy:

environment(texreg2) <- asNamespace('texreg')

Now you can call your new function. My additions include three lines and a name for the dependent variable, similar to stargazer.

texreg2(out, dep.var = "Normalize Citation Score")

\begin{table}
\begin{center}
\begin{tabular}{l c c c c }
\\[-1.8ex]\hline
& \multicolumn{4}{c}{\textit{Dependent variable:}} \\
\cline{2-5}
\\[-1.8ex] & \multicolumn{4}{c}{Normalize Citation Score} \\
\hline
 & Model 1 & Model 2 & Model 3 & Model 4 \\

Finally, if you don't like this method, you can manipulate the output with regex, checkout this question .