[R] Evaluation of an expression as function argument

baptiste auguie ba208 at exeter.ac.uk
Wed Apr 29 22:41:07 CEST 2009


Try this,

> items <- c(list(col=2),list(pch=2))
>
> par(mfrow=c(2, 1))
> for (ii in seq(2)) {
>  do.call(function(x, y, ... ) plot(1:10, ...), items[ii])
> }

?do.call


HTH,

baptiste


On 29 Apr 2009, at 19:30, Sebastien Bihorel wrote:

> Dear R-users,
>
> I would like to know if is it possible to set a function argument as  
> an
> evaluated expression. I have tried several syntaxes, including the
> following example, but could not get it anything to run. The plot
> function is used here but I would like to later apply the same  
> approach
> to other functions.
>
> ##########################
> items <- c(expression(col=2),expression(pch=2))
>
> for (in in seq(2)) {
>  plot(1:10, eval(items[i]))
> }
> ##########################
>
> Thanks in advance for your input.
>
> Sebastien
>
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_____________________________

Baptiste Auguié

School of Physics
University of Exeter
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Exeter, Devon,
EX4 4QL, UK

Phone: +44 1392 264187

http://newton.ex.ac.uk/research/emag



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