[R] Graphic legend with mathematical symbol, numeric variable and character variable

[Peter Ehlers]

On 2012-03-20 06:09, "ECOTIÈRE David (Responsable d'activité) - CETE 
Est/LRPC de Strasbourg/6 Acoustique" wrote:
> Hi,
>
> I'd like to make a legend with a mix of mathematical symbol (tau),
> numeric variable and character variables.I have tried :
>
>
> types<-c("Type 1","Type 2","Type 2")
> tau<-c(1,3,2)
> legend(x="topright",legend=paste(types,"tau=",expression(tau)))
>
>
>
> but it doesn't work: the 'tau' symbol is not written in its 'symbol
> style' but as 'tau'
>
> Any (good) idea ?
> Thank you in advance !
>
> David

Does this do what you want:

   types <- paste('Type', 1:3, sep='~')
   mytau <- 4:6
   leg <- parse(text=paste(types, "~~tau==", mytau, sep='~'))
   plot(0)
   legend('topright', legend=leg)

The '~' symbols generate spaces; use more if you want more spacing.


Peter Ehlers