[R] Passing expression as argument to do.call

[Duncan Murdoch]

On 7/2/2009 4:34 PM, Sebastien Bihorel 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?

Put the expression in a list.  See below...

> 
> 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")

Needs *'s or paste, i.e.

title2 <- expression ("1 " * mu  * "g")

> 
> do.call(plot, c(foo, mylist, main=title))

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

Duncan Murdoch

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