How to plot an expression-label with variable text

[Dieter Menne]

Disclaimer: I have read plotmath, but maybe it's too late today:

How do I get the two labels to be the same:

plot.new()
lab =expression(paste("Estimated ", t[50]," from tgv"))
text(0.5,0.5,lab)
# Should look the same as above. I could not get the substitute right:
what = "tgv"
lab =expression(paste("Estimated ", t[50]," from ",what))
text(0.5,0.2,lab)


Dieter

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[baptiste auguie-5]

hi,

try this

lab =bquote(paste("Estimated ", t[50]," from ",.(what)))


HTH,

baptiste

On 27 August 2010 20:19, Dieter Menne <[hidden email]> wrote:
>
> plot.new()
> lab =expression(paste("Estimated ", t[50]," from tgv"))
> text(0.5,0.5,lab)
> # Should look the same as above. I could not get the substitute right:
> what = "tgv"
> lab =expression(paste("Estimated ", t[50]," from ",what))
> text(0.5,0.2,lab)
>

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and provide commented, minimal, self-contained, reproducible code.

[David Winsemius]

On Aug 27, 2010, at 2:19 PM, Dieter Menne wrote:

> Disclaimer: I have read plotmath, but maybe it's too late today:
>
> How do I get the two labels to be the same:
>
> plot.new()
> lab =expression(paste("Estimated ", t[50]," from tgv"))
> text(0.5,0.5,lab)
> # Should look the same as above. I could not get the substitute right:
> what = "tgv"
> lab =expression(paste("Estimated ", t[50]," from ",what))
> text(0.5,0.2,lab)

The problem with that method (I think) is that expression protects its  
arguments to some extent. The help page wording is that it is  
"special" and does not evaluate its arguments although you seem to  
have gotten the paste() function evaluated. Try:

plot.new()
lab <- expression(paste("Estimated ", t[50]," from tgv"))
text(0.5,0.5,lab)
# Should look the same as above. I could not get the substitute right:
what <- "tgv" ; expr <- paste("Estimated t[50] from ", what)
lab <- as.expression(expr)  # expression() does not satisfy
text(0.5,0.2,lab)

--
David Winsemius, MD
West Hartford, CT

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and provide commented, minimal, self-contained, reproducible code.

[Dieter Menne]

Thanks to both of you. I noted that my example was over-simplified. Looks like I need to correct the environment when nested in a function, but I have to catch the last bus now.

Dieter


plotExp = function(what) {
  plot.new()
  lab =expression(paste("Estimated ", t[50]," from tgv"))
  text(0.5,0.5,lab)
  # Should look the same as above. Looks like I need a substitute....
  lab =bquote(paste("Estimated ", t[50]," from ",.(what))) ##<<need environment
  text(0.5,0.2,lab)
}
plotExp(what)

[David Winsemius]

On Aug 27, 2010, at 2:28 PM, baptiste auguie wrote:

> hi,
>
> try this
>
> lab =bquote(paste("Estimated ", t[50]," from ",.(what)))

bquote doesn't need the paste() if you use plotmath separators:

lab =bquote(Estimated ~t[50]~from~.(what))
text(0.5,0.2,lab)

>
>
> HTH,
>
> baptiste
>
> On 27 August 2010 20:19, Dieter Menne <[hidden email]>  
> wrote:
>>
>> plot.new()
>> lab =expression(paste("Estimated ", t[50]," from tgv"))
>> text(0.5,0.5,lab)
>> # Should look the same as above. I could not get the substitute  
>> right:
>> what = "tgv"
>> lab =expression(paste("Estimated ", t[50]," from ",what))
>> text(0.5,0.2,lab)
>>

--
David Winsemius, MD
West Hartford, CT

______________________________________________
[hidden email] 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.

[David Winsemius]

On Aug 27, 2010, at 2:51 PM, Dieter Menne wrote:

>
> Thanks to both of you. I noted that my example was over-simplified.  
> Looks
> like I need to correct the environment when nested in a function,  
> but I have
> to catch the last bus now.
>
> Dieter
>
>
> plotExp = function(what) {
>  plot.new()
>  lab =expression(paste("Estimated ", t[50]," from tgv"))
>  text(0.5,0.5,lab)
>  # Should look the same as above. Looks like I need a substitute....
>  lab =bquote(paste("Estimated ", t[50]," from ",.(what))) ##<<need
> environment
>  text(0.5,0.2,lab)
> }
> plotExp(what)
>

Hope you caught the bus. Doesn't appear that an environment is needed  
if you don't add the paste() operation:

what= "tgv"
plotExp <- function(what) {
  plot.new()
  lab =expression(paste("Estimated ", t[50]," from tgv"))
  text(0.5,0.5,lab)
   lab =bquote(Estimated~t[50]~ from ~.(what) ) ;  text(0.5,0.2,lab)
    }
plot(what)

Furthermore I could not see from what infirmities the first version  
suffered.


David Winsemius, MD
West Hartford, CT

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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.

[Dieter Menne]

For the record: lattice behaves slightly differently, it requires an "as.expression" with bquote.

Dieter

plotExp <- function(what) {
  plot.new()
  lab = bquote(Estimated~t[50]~ from ~.(what) ) ;
  text(0.5,0.2,lab)
}
plotExp("tgv")

library(lattice)
plotLattice <- function(what) {
  lab = bquote(Estimated~t[50]~ from ~.(what) ) ;
  # Note that ylab is wrong, xlab is correct
  xyplot(1~1,xlab=as.expression(lab), ylab=lab)
}
plotLattice("tgv")