R help - Jan 2010 - plotting Formulas with greek letters and variable values (expression, substitute, paste, ...)

Hallo together,

I want to write a formula of the type

http://n4.nabble.com/file/n1016112/expression.gif 







into my plot, where the values 1.234 and -0.567 should origin from variables
in the program. The threads in this forum gave me some ideas that the
functions expression(), paste(), and substitute() will get me there but I
just cannot figure out how to do it. The closest I got is:

text(0,7.5,substitute(expression(paste(symbol("t"),"(A) =
",c1 +
lg(A^c2),sep="")),list(c1=0,456,c2=-0.123)),pos=4)

Thankful for any suggestions!
Daniel
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On 17.01.2010 18:47, rrookie1982 wrote:
> text(0,7.5,substitute(expression(paste(symbol("t"),"(A) =
",c1 +
> lg(A^c2),sep="")),list(c1=0,456,c2=-0.123)),pos=4)
>
It is much easier, just write the formula down in R syntax and 
substitute the relevant variables as in:

text(0, 7.5, substitute(tau(A) == a*lg(A^b), list(a=1.234, b=-0.567)))

Best,
Uwe Ligges

Try bquote:

a <- 0.1; b <- 0.2
plot(0, main = bquote(tau(A) == .(a)*lg(A^.(b))))


On Sun, Jan 17, 2010 at 12:47 PM, rrookie1982 <desser1 at uni-bonn.de>
wrote:
>
> Hallo together,
>
> I want to write a formula of the type
>
> http://n4.nabble.com/file/n1016112/expression.gif
>
>
>
>
>
>
>
> into my plot, where the values 1.234 and -0.567 should origin from
variables
> in the program. The threads in this forum gave me some ideas that the
> functions expression(), paste(), and substitute() will get me there but I
> just cannot figure out how to do it. The closest I got is:
>
> text(0,7.5,substitute(expression(paste(symbol("t"),"(A) =
",c1 +
> lg(A^c2),sep="")),list(c1=0,456,c2=-0.123)),pos=4)
>
> Thankful for any suggestions!
> Daniel
> --
> View this message in context:
http://n4.nabble.com/plotting-Formulas-with-greek-letters-and-variable-values-expression-substitute-paste-tp1016112p1016112.html
> Sent from the R help mailing list archive at Nabble.com.
>
> ______________________________________________
> R-help at r-project.org mailing list
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> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>

rrookie1982 wrote:
> 
> I want to write a formula of the type
> 
>  http://n4.nabble.com/file/n1016112/expression.gif 
> 
> into my plot, where the values 1.234 and -0.567 should origin from
> variables in the program.
> 

Uwe Ligges-3 wrote:
> 
> It is much easier, just write the formula down in R syntax and 
> substitute the relevant variables as in:
> 
> text(0, 7.5, substitute(tau(A) == a*lg(A^b), list(a=1.234, b=-0.567)))
> 

Gabor Grothendieck wrote:
> 
> Try bquote:
> 
> a <- 0.1; b <- 0.2
> plot(0, main = bquote(tau(A) == .(a)*lg(A^.(b))))
> 
Wow, those two examples are indeed much simpler than my tries and work just
fine. Now I just will have two choose which way to go:
> suba <- 1.234; subb <- -0.567
> text(0, 5,substitute(tau(A) == a*lg(A^b), list(a=suba, b=subb)),pos=4)  ##
> and
> text(0, 5,bquote(tau(A) == .(suba)*lg(A^.(subb))),pos=4)
both work exactly how I wanted them to do.
Thank you Uwe and Gabor

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