R help - Jul 2004 - expression + paste + arguments + ...

dear R wizards:  I would like to write a function that roughly places 
the equivalent of the following latex text into the current plot:

   \newcommand{ \placesigma }[4]{ \put(\#1,\#2){ \sigma_{A , #3} = #4 }

I cannot figure out how to do this.  I know I have to use a function 
that uses expressions in a text() invoke.  But passing arguments and 
nesting strings and expressions has so far not worked for me.  I hope 
this is an obvious question---if not, please just tell me and I can 
give up.  help appreciated.

sincerely,

/iaw

I don't know latex, but have you looked at "?plotmath", including 
'demo(plotmath)', the examples in the documentation, and an R site 
search suggested in the posting guide 
(http://www.R-project.org/posting-guide.html)?  What you want is 
probably fairly easy, once you parse the "plotmath" documentation. 
hope
this helps.  spencer graves

ivo_welch-rstat8783 at mailblocks.com wrote:
>
> dear R wizards:  I would like to write a function that roughly places 
> the equivalent of the following latex text into the current plot:
>
>   \newcommand{ \placesigma }[4]{ \put(\#1,\#2){ \sigma_{A , #3} = #4 }
>
> I cannot figure out how to do this.  I know I have to use a function 
> that uses expressions in a text() invoke.  But passing arguments and 
> nesting strings and expressions has so far not worked for me.  I hope 
> this is an obvious question---if not, please just tell me and I can 
> give up.  help appreciated.
>
> sincerely,
>
> /iaw
>
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://www.stat.math.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide! 
> http://www.R-project.org/posting-guide.html

ivo_welch-rstat8783 at mailblocks.com wrote:
> 
> dear R wizards:  I would like to write a function that roughly places 
> the equivalent of the following latex text into the current plot:
> 
>   \newcommand{ \placesigma }[4]{ \put(\#1,\#2){ \sigma_{A , #3} = #4 }
???
You are "just" defining a new LaTeX command ... nothing will be
printed
in LaTeX.


Instead of using \put, you can specify coordinates as usual in R using 
text(), title() or mtext().
Instead of "\sigma_{A , #3} = #4", you can use

   substitute(sigma[v3] == v4, list(v3 = paste("A,",v3), v4 = v4))

which leads to, e.g.

   plot(1:10)
   v3 <- 99
   v4 <- 55
   text(4, 1, label = substitute(sigma[v3] == v4,
                  list(v3 = paste("A,",v3), v4 = v4)))

See also ?plotmath and the R Help Desk Column in R News 2 (3).

Uwe Ligges

> I cannot figure out how to do this.  I know I have to use a function 
> that uses expressions in a text() invoke.  But passing arguments and 
> nesting strings and expressions has so far not worked for me.  I hope 
> this is an obvious question---if not, please just tell me and I can give 
> up.  help appreciated.
> 
> sincerely,
> 
> /iaw
> 
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://www.stat.math.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide! 
> http://www.R-project.org/posting-guide.html