On Sat, 2007-03-17 at 21:56 -0500, Marc Schwartz wrote:
> On Sat, 2007-03-17 at 22:01 -0400, Chabot Denis wrote:
> > Hi,
> >
> > As part of the legend to a plot, I need to have the "n" in italics
> > because it is a requirement of the journal I aim to publish in:
> > "This study, n = 3293"
> >
> > Presently I have:
> > legend(20, 105, "This study, n = 3293", pch=1, col=rgb(0,0,0,0.5),
> > pt.cex=0.3, cex=0.8, bty="n")
> >
> > I suppose I could leave a blank in place of the "n", then issue a
> > text call where I'd use font=3 for a single letter, "n". But it will
> > be tricky to find the exact location to use.
> >
> > Is there a way to switch to font=3 just for one letter within a string?
> >
> > Thanks in advance,
> >
> > Denis Chabot
>
> Denis,
>
> Try something like this:
>
> plot(20, 100)
>
> leg <- legend(20, 105, "This study, = 3293", pch = 1,
> col=rgb(0,0,0,0.5), pt.cex = 0.3, cex = 0.8,
> bty = "n")
>
> text(leg$text$x + strwidth("This study, ", cex = 0.8),
> leg$text$y, "n", font = 3, cex = 0.8, adj = c(0, 0.5))
>
>
> Note that legend returns a list structure, which contains the x and y
> coordinates of the start of the text strings that are plotted. So I get
> that information for your line of text.
>
> Next, I use strwidth() to calculate, in user coordinates, the length of
> the characters preceding the 'n', including spaces. We add that
> distance to the x coordinate returned in the legend call.
>
> I also use the 'adj' argument in the text() call, so that it is in synch
> with the same parameters in legend() for alignment with the other
> letters.
>
> See ?strwidth for more information.
>
> You may have to tweak the horizontal spacing of the 'n' a bit, depending
> upon the rest of your graph.
Denis,
I thought of another approach, using plotmath.
First, create a text expression, specifying that the 'n' should be
italicized. Then use that expression in the legend() call.
txt <- expression(paste("This study, ", italic(n), " = 3293"))
plot(20, 100)
legend(20, 105, txt, pch = 1, col=rgb(0,0,0,0.5),
pt.cex = 0.3, cex = 0.8, bty = "n")
That's easier that the first solution. See ?plotmath
HTH,
Marc Schwartz
______________________________________________
R-help@stat.math.ethz.ch 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.
