[R] Are there better ways to save and restore par() settings
dwinsemius at comcast.net
Sat May 15 00:19:32 CEST 2010
On May 14, 2010, at 5:45 PM, Duncan Murdoch wrote:
> On 14/05/2010 3:51 PM, David Winsemius wrote:
>> Some of the help page examples use the form:
>> opar <- par(<something>)
>> .....plotting activities...
>> This seems to "work" well, yet I have read in some places
> Please include commented, retrievalbe citations for "some places".
In the examples from help(par) I see:
p <- par(mfrow = c(2, 2),
# 2 x 2 pictures on one plot pty = "s")
# square plotting region,
# independent of device size
## At end of plotting, reset to previous settings:
# Alternatively, op <- par(no.readonly = TRUE)
# the whole list of settable par's.
## do lots of plotting and par(.) calls, then reset: par(op)
## Note this is not in general good practice
Was it only with the use of the "no.read.only" parameter that one is
supposed to avoid the form I illustrated. I had assumed it applied to
>> that it is not the preferred method to keep you parameters from
>> getting corrupted. What is the preferred method?
> The above, with the restore wrapped in on.exit(), as your sources
> should have said.
Perhaps it was implied in a manner to which I was not properly
receptive. The only place I see on.exit() on the par help page is in
the final example. I do not see a link to that function in the that
help page, and I had read it but assumed it was related to "exit"-ing
an R session. On visiting the on.exit help page for the first time in
my life, I see that its primary use is with graphics device calls. So
we are being advised to write that wrapper function each time we might
be making a par-changing plot?
> Duncan Murdoch
>> A worked example from a recent posting with minor additions:
>> opar <- par(mar=c(3,5,0,5))
>> layout(rbind(c(4,1,1,5), c(2,2,3,3)), widths=c(1,1,1,1),
>> barplot(0,0, axes=FALSE)
>> legend(x=0.5, y=0, legend=c("Example 1", "Example 2"),
>> pch=c(1,2), cex=1.5, xjust=1, yjust=0.5, bty="n")
>> plot(1:10,1:10, pch=1)
>> plot(1:20,1:20, pch=2)
David Winsemius, MD
West Hartford, CT
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