Question

How can I produce a Sweave (or pgfSweave) document without angle brackets “>” in front of code chunks? I want people to be able to cut and paste my code directly from the pdf output. Here’s a snippet of my document with a code chunk:

Notice that because our incidence matrix consists of 0’s and 1’s, the off-diagonal entries represent the total number of common columns, which is exactly what we wanted. We’ll use the %*% operator to tell R to do this. Let’s first take a look at a small example using toy data of people and groups to which they belong. We’ll coerce the data to an incidence matrix using the table() function, then multiply the incidence matrix by its transpose to get the number of common groups between people.

>\> ToyDat <- data.frame(person = c("Sam", "Sam", "Sam", "Greg", "Tom", "Tom"), group = c("a", "b", "c", "a", "b", "c"), stringsAsFactors = F)
>\> ToyDatM <- as.matrix(table(ToyDat)) 
>\> ToyDatM

But I want the code to look like:

> ToyDat <- data.frame(person = c("Sam", "Sam", "Sam", "Greg", "Tom", "Tom"), group = c("a", "b", "c", "a", "b", "c"), stringsAsFactors = F)    
> ToyDatM <- as.matrix(table(ToyDat)) 
> ToyDatM

Answer 1

I think options(prompt = " ") at the top of your script will do it.

prompt (in options()) controls the text string used for the prompt in an interactive session and I’m assuming it will do the same for a document processed through Sweave.

EDIT: Thanks to Ben Bolker for pointing out that options(prompt = " ", continue = " ") will also take care of the “+” problem as well.