[R] Two == expressions in bquote

[Bert Gunter]

Peter's way is better than mine.

Bert Gunter
Genentech Nonclinical Biostatistics
 
 

-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] On
Behalf Of Peter Dalgaard
Sent: Monday, January 25, 2010 12:57 PM
To: Larry Hotchkiss
Cc: r-help at r-project.org
Subject: Re: [R] Two == expressions in bquote

Larry Hotchkiss wrote:
> Hi,
> 
> I want to put text on a plot containing something like: a = b^2 = <squared
numeric value of b> using bquote.
> 
> Example:
> 
>   mu = 5
>   plot(1:10,1:10)
>   text(2,8, bquote(delta == mu^2))            # This works
>   text(2.5,8, bquote(phantom(0) == .(mu^2)))  # but is unpredictable
> 
>   text(2,8, bquote(delta == mu^2 == .(mu^2))) # This doesn't work
> 
> The last text function returns the error:
> 
>      Error: unexpected '==' in "  text(2,8, bquote(delta == mu^2 =="

The comparison operators are not associative (they once were, but people 
were getting surprises from 3 > 2 > 1 evaluating to TRUE > 1 evaluating 
to FALSE). A set of suitably placed braces should clear things up:

text(2,8,bquote(delta == {mu^2 == .(mu^2)}))


> The first two text functions work in this example, using a default
graphics window on a 64-bit Windows machine, and either R 2.11.0 development
edition for 64-bit Windows or R 9.2.2 on the same machine ((x 86)). 
> 
> I don't mind the two statements except that when trying to automate this
by using the base x coordinate + epsilon*max(x), for example --
> 
>   x <- 1:10
>   epsilon=0.05
>   text(2+esilon*max(x),8, bquote(phantom(0) == .(mu^2)))
> 
> for the x position on the 2nd text function, the position of the
additional text is not predictable.
> 
> Thanks,
> 
> Larry Hotchkiss
> 
> ______________________________________________
> R-help at 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.


-- 
    O__  ---- Peter Dalgaard             Øster Farimagsgade 5, Entr.B
   c/ /'_ --- Dept. of Biostatistics     PO Box 2099, 1014 Cph. K
  (*) \(*) -- University of Copenhagen   Denmark      Ph:  (+45) 35327918
~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk)              FAX: (+45) 35327907

______________________________________________
R-help at 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.