substitute(expr, env=NULL) quote(expr, env=NULL)
substitute
returns the expression which was typed
as the value of a formal argument.
quote
is a synonym useful to lisp programmers.
The typical use of this is to create informative
labels for data sets and plots.
The following example shows a simple use of this facility.
It uses the functions deparse
and substitute
to create labels for a plot which are character string versions
of the actual arguments to the function myplot
.
myplot <- function(x, y) plot(x, y, xlab=deparse(substitute(x)), ylab=deparse(substitute(y)))