Rendering grid graphics in Sweave

Question

I have a short routine which arranges ggplot and grid graphics using the grid.arrange function in the package gridExtras. I need to render the output from my routine (which nominally prints using grid.draw, or returns the grid object as an option) in my Sweave documentation. I'm at a loss how to do this, since the say I've been using "print" doesn't work the same way as with a pure ggplot graphic. I've tried:

g <- ggkm(survfit.object, returns=T)
print(g)

where g is the object created by grid.arrange, and has class

> class(g)
[1] "frame" "gTree" "grob"  "gDesc"

Any help would be appreciated

Abhijit

Answer 1

Printing the object as it's created rather than printing the saved object seems to work, although I couldn't explain why ...

\documentclass{article}
\begin{document}


<<>>=
library(ggplot2)
library(gridExtra)

d <- data.frame(x=1:10,y=1:10,z=runif(10))
g1 <- qplot(x,y,data=d)
g2 <- qplot(x,z,data=d)
@ 

<<fig=TRUE,results=hide>>=
print(grid.arrange(g1,g2,ncol=2))
@ 

\end{document}