Inserting superscripts in free-format text line

On 2012-08-20 12:27, William Dunlap wrote:

paste() is ok, but it must be enclosed in expression(),
just like the case that worked.

plot(-15:15,15:-15)
text(x=5, y=4.5, expression(test^1) )
text(x=1, y=11, expression(paste("This is a ", test^1, " of the  
Emergency Broadcast System.")))

plotmath only works on expressions, not on the strings
that a call to paste would produce.

It's a matter of paste, of course (whoops, I mean a matter of _t_aste),
but I agree with David that, in plotmath situations, paste() is often
not the best way to proceed, especially in view of the fact that
plotmath's paste() doesn't recognize the 'sep=' argument; this often
confounds useRs.
In the above, example, I would prefer to use concatenation of the
string pieces with either '~' (a space) or '*` (no space):

   text(x=1, y=11, expression("This is a" ~ test^1 ~ "of the
           Emergency Broadcast System."))

or

   text(x=1, y=11, expression("This is a " * test^1 * " of the
           Emergency Broadcast System."))

If one is going to use plotmath expressions frequently, then these
two handy little symbols are worth knowing.

Peter Ehlers

Bill Dunlap
Spotfire, TIBCO Software
wdunlap tibco.com

-----Original Message-----
From: r-help-bounces at r-project.org  
[mailto:r-help-bounces at r-project.org] On Behalf
Of David Winsemius
Sent: Monday, August 20, 2012 12:15 PM
To: Brian Kriegler
Cc: r-help at r-project.org
Subject: Re: [R] Inserting superscripts in free-format text line


On Aug 20, 2012, at 11:35 AM, Brian Kriegler wrote:

I would like to insert a superscript in a body of text (e.g., a
title or axis label), where the superscript is not necessarily at
the end of the text.  For example, suppose a title read, "This is a
Test^1 of the Emergency Broadcast System" where there is a
superscript 1 after the word Test.

As a starting point for what I'm trying to do, the following shows a
superscript:
x=10
plot(x)
text(x=1, y=12, expression("test"^1)

Not on my device. No closing paren.

Why not:

plot(1:10)
text(x=5, y=4.5, expression(test^1) )

You do not need quotes in plotmath expressions unless they are
reserved plotmath function names. People reach for paste() in far too
many situations.

But, the following does not show a superscript:
x=10
plot(x)
text(x=1, y=11, paste("This is a", expression("test"^1), "of the
Emergency Broadcast System.")

And why not:

   expression(This~is~a~test^1~of~the~Emergency~Broadcast~System.)

--

David Winsemius, MD
Alameda, CA, USA