Dear Bert,
thanks, I was confused (of course). So the right question would have been: How
to convert strings to expressions (plotmath expressions). But that I could
easily find, thanks.
Cheers,
Marius
Here is the working example (showing plotmath and just-character labels):
require(grid)
tau <- c(0.25, 0.75)
alpha <- c(0.95, 0.99, 0.999)
a <- array(1:6, dim=c(2,3), dimnames=list(tau=tau, alpha=alpha))
dimnames(a)$tau[1] <- "tau==0.25" ## dimnames(a)$tau <- paste0("tau==", tau)
dimnames(a)
gl <- grid.layout(1, 2, default.units="inch", widths=c(2,2), heights=c(2,2))
## grid.show.layout(gl)
pushViewport(viewport(layout=gl))
pushViewport(viewport(layout.pos.row=1, layout.pos.col=1))
grid.rect(gp=gpar(col=NA, fill="gray80"))
grid.text(parse(text=dimnames(a)[["tau"]][1]), x=0.5, y=0.5)
upViewport()
pushViewport(viewport(layout.pos.row=1, layout.pos.col=2))
grid.rect(gp=gpar(col=NA, fill="gray50"))
grid.text(parse(text=dimnames(a)[["tau"]][2]), x=0.5, y=0.5)
upViewport()
________________________________________
From: Bert Gunter [gunter.ber...@gene.com]
Sent: Thursday, October 04, 2012 4:42 PM
To: Hofert Jan Marius
Cc: mailman, r-help
Subject: Re: [R] How to convert array dim names to expressions for plotting?
It is not clear to me what you mean by "expressions" in this context.
Dimension names but be character strings -- see ?dimnames, which says:
"The dimnames of a matrix or array can be NULL or a list of the same
length as dim(x). If a list, its components are either NULL or a
character vector with positive length of the appropriate dimension of
x. "
If somehow you expect plotmath type drawn objects or R expression
objects, then you are confused. If I am just misunderstanding what you
want, then I am confused.
-- Bert
On Thu, Oct 4, 2012 at 7:27 AM, Hofert Jan Marius
<marius.hof...@math.ethz.ch> wrote:
> Hi,
>
> I would like to use the dim names of an array as labels in a plot. In the
> case of character labels, this is no problem. However, if I would like to
> pass expressions through array dim names, they only appear as character
> labels in the plot and are not evaluated as expressions (see the minimal
> example below). How can this be done?
>
> Cheers,
>
> Marius
>
>
> require(grid)
>
> tau <- c(0.25, 0.75)
> alpha <- c(0.95, 0.99, 0.999)
> a <- array(1:6, dim=c(2,3), dimnames=list(tau=tau, alpha=alpha))
>
> taulabs <- as.expression(lapply(tau, function(t) bquote(tau==.(t))))
> dimnames(a)$tau <- taulabs # does not create expressions
> dimnames(a) # => no expressions
> dimnames(a)$tau[[1]] <- taulabs[1]
> dimnames(a)$tau[[2]] <- taulabs[2]
> dimnames(a) # => now characters
>
> gl <- grid.layout(1, 2, default.units="inch", widths=c(2,2), heights=c(2,2))
> ## grid.show.layout(gl)
> pushViewport(viewport(layout=gl))
>
> pushViewport(viewport(layout.pos.row=1, layout.pos.col=1))
> grid.rect(gp=gpar(col=NA, fill="gray80"))
> grid.text(dimnames(a)[["tau"]][1], x=0.5, y=0.5)
> upViewport()
>
> pushViewport(viewport(layout.pos.row=1, layout.pos.col=2))
> grid.rect(gp=gpar(col=NA, fill="gray50"))
> grid.text(dimnames(a)[["tau"]][2], x=0.5, y=0.5)
> upViewport()
>
> ______________________________________________
> R-help@r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
--
Bert Gunter
Genentech Nonclinical Biostatistics
Internal Contact Info:
Phone: 467-7374
Website:
http://pharmadevelopment.roche.com/index/pdb/pdb-functional-groups/pdb-biostatistics/pdb-ncb-home.htm
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