R help - Sep 2011 - Mathematical expressions in the group labels in lattice

Hi,

I am working with the lattice package and I want to label to groups in the
xyplots with mathematical expressions.
I short example for this

library(lattice)

Case<-factor(rep(1:2,each=300))
xx<-rnorm(600,0,1)
yy<-rnorm(600,0,1)
xyplot(yy~xx|Case)

This results in two scatter plots with label "1" and "2". I
would like to substitute this labels by math expression. I used the following
code

Case<-factor(rep(1:2,each=300))
levels(Case) <- c(expression(R^2),expression(sigma_[i]))
xx<-rnorm(600,0,1)
yy<-rnorm(600,0,1)
xyplot(yy~xx|Case)

But the label did not change to mathematical expressions. Any ideas?
Thank you very much for your help.

 		 	   		  
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On Sep 13, 2011, at 8:30 AM, Timo Schmid wrote:
>
> Hi,
>
> I am working with the lattice package and I want to label to groups  
> in the xyplots with mathematical expressions.
> I short example for this
>
> library(lattice)
>
> Case<-factor(rep(1:2,each=300))
> xx<-rnorm(600,0,1)
> yy<-rnorm(600,0,1)
> xyplot(yy~xx|Case)
>
> This results in two scatter plots with label "1" and
"2". I would
> like to substitute this labels by math expression. I used the  
> following code
>
> Case<-factor(rep(1:2,each=300))
> levels(Case) <- c(expression(R^2),expression(sigma_[i]))
> xx<-rnorm(600,0,1)
> yy<-rnorm(600,0,1)
> xyplot(yy~xx|Case)
>
> But the label did not change to mathematical expressions. Any ideas?
You should be looking at the strip.custom function. It has worked  
examples.

> Thank you very much for your help.

-- 
David Winsemius, MD
West Hartford, CT

On Sep 13, 2011, at 9:30 AM, David Winsemius wrote:
>
> On Sep 13, 2011, at 8:30 AM, Timo Schmid wrote:
>
>>
>> Hi,
>>
>> I am working with the lattice package and I want to label to groups  
>> in the xyplots with mathematical expressions.
>> I short example for this
>>
>> library(lattice)
>>
>> Case<-factor(rep(1:2,each=300))
>> xx<-rnorm(600,0,1)
>> yy<-rnorm(600,0,1)
>> xyplot(yy~xx|Case)
>>
>> This results in two scatter plots with label "1" and
"2". I would
>> like to substitute this labels by math expression. I used the  
>> following code
>>
>> Case<-factor(rep(1:2,each=300))
>> levels(Case) <- c(expression(R^2),expression(sigma_[i]))
>> xx<-rnorm(600,0,1)
>> yy<-rnorm(600,0,1)
>> xyplot(yy~xx|Case)
>>
>> But the label did not change to mathematical expressions. Any ideas?
>
> You should be looking at the strip.custom function. It has worked  
> examples.
The worked examples only illustrate a few of the arguments. The  
factor.levels argument is probably what you wanted:

xyplot(yy~xx|Case,
     strip=strip.custom(factor.levels= c( expression(R^2),  
expression(sigma_[i]) )
      )
>
>
>> Thank you very much for your help.
>
>
> -- 
> David Winsemius, MD
> West Hartford, CT
>
> ______________________________________________
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> 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, MD
West Hartford, CT