Looping Through a Data Frame with Sweave

gen_pdf.R

# Generate PDF for a Pid
gen_pdf <- function(sdf){
  rnw_file <- sprintf("%s.rnw", unique(sdf$Pid))
  tex_file <- sub('.rnw$', '.tex$', rnw_file)
  file.copy('template.Rnw', rnw_file)
  Sweave(rnw_file)
  tools::texi2pdf(tex_file, clean = TRUE, quiet = TRUE)
  unlink(c(rnw_file, tex_file))
}

# Loop through all unique Pids
library(plyr)
d_ply(df, .(Pid), gen_pdf)

template.Rnw

\documentclass{article}
\usepackage{graphicx}

\begin{document}
\SweaveOpts{concordance=TRUE}

% Modify the text as needed. Note that sdf is a subset of the original
% data frame for a given Pid.

This is the report for \Sexpr{unique(sdf$Pid)}.

% Generate the plot
<<plot, fig = T, width = 5, height = 5>>=
plot(sdf$ksap1, sdf$ksap2)
@	

\end{document}