Re: [R] Defining binary indexing operators

From: Gabor Grothendieck <ggrothendieck_at_gmail.com>
Date: Thu 28 Apr 2005 - 08:21:10 EST

On 4/27/05, Ali - <saveez@hotmail.com> wrote:
>
> Assume we have a function like:
>
> foo <- function(x, y)
>
> how is it possible to define a binary indexing operator, denoted by $, so
> that
>
> x$y
>
> functions the same as
>
> foo(x, y)

  Here is an example. Note that $ does not evaluate y so you have to do it yourself:

x <- structure(3, class = "myclass")
y <- 5
foo <- function(x,y) x+y
"$.myclass" <- function(x, i) { i <- eval.parent(parse(text=i)); foo(x, i) } x$y # structure(8, class = "myclass")

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