Thank you for telling me a fix.
But I still don't know if this behavior is what is intended. I used
bquote(...) because the plotmath(...) help page refers to bquote and gives an
example like this. I suspect most users will be baffled by this kind of
behavior, especially since it does not occur when there is one plot. By this I
mean that I can draw one plot and title it with the same string using bquote(
). If I change the value of i, and redraw the graph, the redrawn graph has the
original value of i in the title, not the updated value. So in this case, an
unevaluated expression is not re-evaluated at draw time?
John
-----xieyi...@gmail.com wrote: -----
To: John Nolan <jpno...@american.edu>
From: Yihui Xie
Sent by: xieyi...@gmail.com
Date: 10/05/2011 11:49PM
Cc: r-help@r-project.org
Subject: Re: [R] Titles changing when a plot is redrawn
I think the problem is your str1 is an unevaluated expression and will
change with the value of i. You should be able to get a fixed title by
this:
par(mfrow = c(2, 1))
for (i in 1:2) {
x <- 1:100
rmse <- sin(x/5) # fake data
plot(x, rmse, main = substitute(list(RMSE(theta), i == z), list(z = i)))
}
Regards,
Yihui
--
Yihui Xie <xieyi...@gmail.com>
Phone: 515-294-2465 Web: http://yihui.name
Department of Statistics, Iowa State University
2215 Snedecor Hall, Ames, IA
On Wed, Oct 5, 2011 at 10:01 PM, John Nolan <jpno...@american.edu> wrote:
> I ran into a problem with titles on graphs. I wanted a graph with
> multiple subplots, with each having a title that involved both
> a Greek letter and an identifier for each graph. Below is a
> simplified version of code to do this. The graph appears fine,
> with the first graph having "i=1" in the title, and the second
> graph having "i=2" in the title. However, when I resize the graph,
> the plot titles change, with both showing "i=2". The titles also
> change when I save the plot to a file using the "File" menu,
> then "Save as" in Windows. Is this what should happen? I
> always thought that titles are static once the graph is
> drawn, and couldn't change.
>
> The problem occurs on some version of R, but not on others.
> It does occur with the latest version of R:
>> str(R.Version())
> List of 13
> $ platform : chr "i386-pc-mingw32"
> $ arch : chr "i386"
> $ os : chr "mingw32"
> $ system : chr "i386, mingw32"
> $ status : chr ""
> $ major : chr "2"
> $ minor : chr "13.2"
> $ year : chr "2011"
> $ month : chr "09"
> $ day : chr "30"
> $ svn rev : chr "57111"
> $ language : chr "R"
> $ version.string: chr "R version 2.13.2 (2011-09-30)"
>
> The problem also occurs on: R 2.13.0 on Win32
> and Mac (R 2.12.0, x86_64-apple-darwin9.8.0)
> The problem DOES NOT occur under R 2.10.0 on Win32.
>
> If the code below is bracketed with pdf("test.pdf")
> and dev.off(), the correct labels appear in the file.
> This behavior doesn't seem to appear if there is only
> one plot.
>
> My guess is that the titles are being reevaluated when
> the plot is redrawn, and since the value of i is 2 when
> the redraw occurs, both labels get set to "i=2". I guess
> "Save as" forces a redraw because a dialog box pops up?
>
> If could be that this behavior is what is intended, and that
> somewhere between R 2.10.0 and R 2.13.2 an old bug was fixed.
> Or this behavior is not what was intended, and a bug was
> introduced. If the former, this should be explained to the user
> somewhere. If the latter, can someone track it down and fix?
>
> John Nolan
>
> #-------------------------------------------------
> par(mfrow=c(2,1))
> for (i in 1:2) {
> x <- 1:100
> rmse <- sin(x/5) # fake data
> plot(x,rmse)
> str1 <- bquote( paste("RMSE(",theta,"), ",i==.(i) ))
> title( str1 )
> }
> #-------------------------------------------------
>
>
> ...........................................................................
>
> John P. Nolan
> Math/Stat Department
> 227 Gray Hall
> American University
> 4400 Massachusetts Avenue, NW
> Washington, DC 20016-8050
>
> jpno...@american.edu
> 202.885.3140 voice
> 202.885.3155 fax
> http://academic2.american.edu/~jpnolan
> ...........................................................................
> ______________________________________________
> R-help@r-project.org mailing list
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> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>
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