[R] Passing expression as argument to do.call

[hadley wickham]

On Thu, Jul 2, 2009 at 3:34 PM, Sebastien
Bihorel<sebastien.bihorel at cognigencorp.com> wrote:
> Dear R-users,
>
> I would like to know how expressions could be passed as arguments to do.call
> functions. As illustrated in the short example below, concatenating lists
> objects and an expression creates an expression object, which is not an
> acceptable argument for do.call. Is there a way to avoid that?
>
> Thanks you
>
> Sebastien
>
>
> foo <- list(x=1:10, y=1:10)
> mylist <- list(pch=6, col=2)
> title <- "1 microgram"
> title2 <- expression ("1 " mu "g")
>
> do.call(plot, c(foo, mylist, main=title))
>
> class(c(foo, mylist, main=title2))
>
> do.call(plot, c(foo, mylist, main=title2))

do.call(plot, c(foo, mylist, list(main=title2)))

Both foo and myllist are already lists, but title2 isn't.

Hadley

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