Thanks, that is exactly what I have been looking for!
On Tue, 21 Feb 2012 11:58:01 +0100
Eik Vettorazzi <e.vettora...@uke.de> wrote:
Hi Sebastian,
how about this:
mycurve <- function (expr) {
do.call(curve,list(substitute(expr),-100,100))
}
mycurve(x^2)
mycurve(sin(x/20))
mycurve(x+x^2-x^3)
cheers
Am 21.02.2012 06:28, schrieb Sebastian Kranz:
Dear List members,
I really, like the feature that one can call R functions
with
mathematical expressions, e.g.
curve(x^2, 0, 1)
I wonder, how I can construct in a simple way a function
like
mycurve = function (expr) {...}
such that that a call
mycurve(x^2)
has the same effect as the call
curve(x^2, -100,100)
Below is some code that works, but it seems much to
complicated: it
first substitutes and deparses the expression, creates a
string with the
new function call and then parses and evaluates the
string again. Does
anybody know a simpler, more elegant solution?
mycurve = function(expr) {
# The following attempt does not work
# curve(substitute(expr),-100,100)
# Transform original expression to a string
org.expr = deparse(substitute(expr))
# Construct a string, parse it and evaluates it
eval(parse(text=paste("curve(",org.expr,",-100,100)",sep="")))
}
mycurve(x^2)
Best regards,
Sebastian
[[alternative HTML version deleted]]
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