[R] character variables in substitute()

[Eik Vettorazzi]

Hi David,
there is a solution using bquote instead of substitute

expr<-bquote(italic(.(pname[1]))==.(params[1])~", 
"~.(as.name(pname[2]))==.(params[2]))
plot(1,1,main=expr)

hth.

dkStevens schrieb:
> In trying to create a plotmath expression for plot labeling, such as 
>
> R = 6, beta = 15
>
> where I want beta to be the Greek beta and, possibly, R in italics (like one
> would get in an explicit expression. The reason for this is that I want to
> write a string builder function that takes vectors of variable names and
> their values and return a plotmath expression for labeling a plot. One
> approach I tried is
>
> pname = c("R","beta")
> params = c(6,15)
> substitute(p == v,list(p = pname[i],v = format(params[i],digits=4))
>
> but this just copies the character strings in pname into the expression. Can
> anyone help me do what I want? How would I manage passing the resulting
> string back to the calling routine? Any help will be much appreciated.
>
>
>   

-- 
Eik Vettorazzi
Institut für Medizinische Biometrie und Epidemiologie
Universitätsklinikum Hamburg-Eppendorf

Martinistr. 52
20246 Hamburg

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