[R] Automating plot labelling in custom function in lapply() ?

[Sundar Dorai-Raj]

Gavin Simpson wrote on 4/29/2005 5:00 AM:
> Dear List,
> 
> Consider the following example:
> 
> dat <- data.frame(var1 = rnorm(100), var2 = rnorm(100),
>                   var3 = rnorm(100), var4 = rnorm(100))
> oldpar <- par(mfrow = c(2,2), no.readonly = TRUE)
> invisible(lapply(dat,
>                  function(x) {
>                    plot(density(x),
>                         main = deparse(substitute(x))) }
>                  )
>           )
> par(oldpar)
> 
> I want to the main title in each of the density plots to be var1, var2, 
> etc. The above code produces x[[1]], x[[2]] etc.
> 
> What do I need to modify to be able to use the name of x as the plot 
> label within in the above situation?
> 
> Thanks in advance,
> 
> Gav

Gav,

I think a `for' loop would be more useful here (not to mention, more 
readable):

dat <- data.frame(var1 = rnorm(100), var2 = rnorm(100),
                   var3 = rnorm(100), var4 = rnorm(100))
oldpar <- par(mfrow = c(2,2), no.readonly = TRUE)
for(v in names(dat))
   plot(density(dat[[v]]), main = v)
par(oldpar)

HTH,

--sundar