R help - Jul 2009 - How to pass a character argument which contains expressions to arg.names in barplot?

Hi all

Can anybody help me with this? I am trying to include in an automatic way
the argument in arg.names in a barplot. I generate the labels I want to
appear below the bars with a for loop, and they contain subscripts, so I
need to use expression

  anch<-0.05
  esp<-4
  for (i in 1:dim(Ntot)[1])
    {
    naux<-Ntot[i,]
    naux2<-naux[naux>0]
    nind<-which(naux>0)
    tit4<-character(0)
    for (j in 1:length(nind))
      {
     
tit4<-c(tit4,paste("expression(n[paste[",i,",",nind[j],"])",sep=""))
      }
    windows()
    barplot(naux2,xlab=eval(expression(substitute(n[i],list(i=i)))),
   
arg.names=tit4,col="gray",width=c(anch,anch),axes=TRUE,xlim=c(0,anch*(esp+2)*length(nind)),
    space=esp,ylim=c(0,max(naux2)),main=paste("State
#",i),yaxp=c(0,M,Mint));lines(c(0,100),c(0,0))
    }   # end of for
 
but I don't get what I expect. R plots literally the contents of tit4 below
each bar, i.e., (for the last value of i in the outer for loop)

"expression(n[paste[5,1])" 
"expression(n[paste[5,2])" 
"expression(n[paste[5,3])" 
"expression(n[paste[5,4])"

Of course, if I write directly
arg.names=c(expression(n[paste(5,1)]),expression(n[paste(5,2)]),expression(n[paste(5,3)]),expression(n[paste(5,4)]))
it works, but then I cannot do ii in an automatic way for all the graphics
coming from the for (i in 1:dim(Ntot)[1]).

I have also tried to store in another variable tit5 the whole expression
as
> tit5
[1]
"c(expression(n[paste[5,1]),expression(n[paste[5,2]),expression(n[paste[5,3]),expression(n[paste[5,4]))"
but it doesn't work neither

I wonder if there is some way that barplot "tells" arg.names to
"evaluate"
the contents of tit4 as expressions, not as characters

I hope I made myself clear enough

Thanks in advance to any response

Cheers!!!!

Javi
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jcano wrote:
> Hi all
> 
> Can anybody help me with this? I am trying to include in an automatic way
> the argument in arg.names in a barplot. I generate the labels I want to
> appear below the bars with a for loop, and they contain subscripts, so I
> need to use expression
> 
>   anch<-0.05
>   esp<-4
>   for (i in 1:dim(Ntot)[1])
>     {
>     naux<-Ntot[i,]
>     naux2<-naux[naux>0]
>     nind<-which(naux>0)
>     tit4<-character(0)
>     for (j in 1:length(nind))
>       {
>      
tit4<-c(tit4,paste("expression(n[paste[",i,",",nind[j],"])",sep=""))
>       }
>     windows()
>     barplot(naux2,xlab=eval(expression(substitute(n[i],list(i=i)))),
>    
>
arg.names=tit4,col="gray",width=c(anch,anch),axes=TRUE,xlim=c(0,anch*(esp+2)*length(nind)),
>     space=esp,ylim=c(0,max(naux2)),main=paste("State
> #",i),yaxp=c(0,M,Mint));lines(c(0,100),c(0,0))
>     }   # end of for
>  
> but I don't get what I expect. R plots literally the contents of tit4
below
> each bar, i.e., (for the last value of i in the outer for loop)
> 
> "expression(n[paste[5,1])" 
> "expression(n[paste[5,2])" 
> "expression(n[paste[5,3])" 
> "expression(n[paste[5,4])"
> 
> Of course, if I write directly
>
arg.names=c(expression(n[paste(5,1)]),expression(n[paste(5,2)]),expression(n[paste(5,3)]),expression(n[paste(5,4)]))
> it works, but then I cannot do ii in an automatic way for all the graphics
> coming from the for (i in 1:dim(Ntot)[1]).
> 
> I have also tried to store in another variable tit5 the whole expression as
>> tit5
> [1]
>
"c(expression(n[paste[5,1]),expression(n[paste[5,2]),expression(n[paste[5,3]),expression(n[paste[5,4]))"
> but it doesn't work neither
> 
> I wonder if there is some way that barplot "tells" arg.names to
"evaluate"
> the contents of tit4 as expressions, not as characters
> 
> I hope I made myself clear enough
> 
> Thanks in advance to any response
> 
> Cheers!!!!
> 
> Javi


Your code is not reproducible at all since you have not provided any 
data (such as Ntot). Anyway, I guess (untested!) what you want is 
(prettified to make the code readable):

anch <- 0.05
esp <- 4
for (i in 1:dim(Ntot)[1]){
   naux <- Ntot[i,]
   nind <- which(naux > 0)
   naux2 <- naux[nind]
   windows()
   barplot(naux2,
     xlab = substitute(n[i], list(i=i)),
     names.arg = as.expression(lapply(nind,
       function(x) substitute(n[list(i,j)], list(i=i, j=x)))),
     col = "gray", width = c(anch, anch), axes = TRUE,
     xlim = c(0, anch*(esp+2)*length(nind)), space = esp,
     ylim = c(0, max(naux2)), main = paste("State#", i),
     yaxp = c(0, M, Mint)
   )
   lines(c(0, 100), c(0, 0))
}



Uwe Ligges

Dear Uwe

Sorry for not included the data, but even as that, it worked!!!!!

Thank you very much for your unvaluable time and effort

Cheers

Javier Cano 
-- 
View this message in context:
http://www.nabble.com/How-to-pass-a-character-argument-which-contains-expressions-to-names.arg-in-barplot--tp24630656p24651375.html
Sent from the R help mailing list archive at Nabble.com.

Surely a fortune, because fortuna can be cruel.


url:    www.econ.uiuc.edu/~roger            Roger Koenker
email    rkoenker at uiuc.edu            Department of Economics
vox:     217-333-4558                University of Illinois
fax:       217-244-6678                Urbana, IL 61801



On Jul 24, 2009, at 3:24 PM, jcano wrote:
>
> Dear Uwe
>
> Thank you very much for your unvaluable time and effort
>
> Cheers
>
> Javier Cano