Hi Hadley,
I tried today your solution to this problem. However, the finally
working code was like
eval(substitute(ggplot( aes_string(...) ))
The qplot code below did not work at all, neither works a
ggplot(aes_string(...))
BTW: Since I am always writing scripts to produce my plots, how can I
split accross multiple lines one command in a R-script? These ggplot
commands can become rather long and the syntax
pl <- ggplot( ........... long expression ................. )
pl <- pl + some_layer( ........... )
is not very intuituve. So, how do I break lines in R-Scripts.
These questions must sound like beginner questions - but I have searched
archives and documentation without success. As we speak of it - is your
book finally out?
Greetings,
Sebastian Weber
On Thu, 2008-03-27 at 07:57 -0500, hadley wickham wrote:
> > Ok, I will try that, thanks. BTW, where is this aes_string option
> > documented, sounds useful? How could I do the same thing with facetting?
> > If I want to save something like ". ~ groupVar" as a string in a
> > variable, could I pass it with facet_string to ggplot?
>
> It's a see also from ?aes (or at least it is in the development
> version). facet_grid should already accept a string instead of a
> function, so it should just work.
>
> > But anyway, I would be curious how to do it with qplot. The basic
> > question is: How to pass the string of a variable to a function which is
> > supposed to interpret it. Aka:
> >
> > var <- "magicVar"
> >
> > fun(doSomeMagic(var))
> >
> > doSomeMagic should then write magicVar at the place.
>
> In general, you can use as.name, substitute and eval:
>
> x <- as.name("mpg")
> y <- as.name("wt")
>
> eval(substitute(qplot(x, y, data=mtcars), list(x=x, y=y)))
>
> Hadley
>
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