Summary Function that is compatible with xtable

If you like to make nice looking documents using Latex, I highly recommend using the ‘xtable‘ package. In most instances, it works quite well for producing a reasonable looking table from an R object. I however recently wanted a LaTeX table from the ‘summary’ function in base R. So naturally I tried:

library(xtable)
set.seed(123)
foo = rnorm(10)
summary(foo)
xtable(summary(foo))

Which gave me the following error:

Error in xtable.table(summary(foo)) :
  xtable.table is not implemented for tables of > 2 dimensions

So I decided to create a simple function that would return a dataframe which is easy to use with xtable. Here is what I came up with.

summaryfunction= function (x){
  if( is.numeric(x)!=TRUE) {stop("Supplied X is not numeric")}
  mysummary = data.frame(
            "Min." =as.numeric( min(x)),
            "1st Qu." = quantile(x)[2],
            "Median" = median(x),
            "Mean" = mean(x),
            "3rd Qu." = quantile(x)[4],
            "Max." = max(x),
            row.names=""
              
            )
  names(mysummary) = c("Min.","1st Qu.","Median","Mean","3rd Qu.","Max.")
  return( mysummary )
  }

Now, when I try to use xtable I get the following output:

% latex table generated in R 3.1.1 by xtable 1.7-4 package
% Tue Nov 04 21:58:07 2014
begin{table}[ht]
centering
begin{tabular}{rrrrrrr}
  hline
 & Min. & 1st Qu. & Median & Mean & 3rd Qu. & Max. \
  hline
 & -1.27 & -0.53 & -0.08 & 0.07 & 0.38 & 1.72 \
   hline
end{tabular}
end{table}

This should lead to an easier way to incorporate more summaries when you are writing your paper, using R and Knitr of course. If you do use knitr, make sure to try the results = ‘asis’ option with xtable from R.