Run Sweave or knitr with objects from existing R session

Question

Suppose I have an object x in my current session:

x <- 1

How can I use this object in an Sweave or knitr document, without

Answer 1

Both Sweave and knitr makes use of the global environment (see globalenv()) when evaluating R code chunks, so whatever in your global environment can be used for your document. (Strictly speaking, knitr uses the parent frame parent.frame() which is globalenv() in most cases)