abbreviate or wrap dimname labels

-----Original Message-----
From: r-help-bounces at stat.math.ethz.ch 
[mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of 
Michael Friendly
Sent: Friday, April 15, 2005 11:12 AM
To: r-help at stat.math.ethz.ch
Subject: [R] abbreviate or wrap dimname labels

For a variety of displays (mosaicplots, barplots, ...) one 
often wants to either abbreviate or wrap long labels, 
particularly when these are made up of several words.
In general, it would be nice to have a function,

abbreviate.or.wrap <-
    function(x, maxlength=10, maxlines=2, split=" ") { }

that would take a character vector or a list of vectors, x, 
and try to abbreviate or wrap them to fit approximately the 
maxlength and maxlines constraints, using the split argument 
to specify allowable characters to wrap to multiple lines.

For example, this two-way table has dimnames too long to be 
displayed nicely in a mosaicplot:

 > library(catspec)
 > library(vcd)
 >
 > data(FHtab)
 > FHtab<-as.data.frame(FHtab)
 >
 > xtable <- xtabs(Freq ~ .,FHtab)
 > lab <- dimnames(xtable)
 > lab

$OccFather
[1] "Upper nonmanual" "Lower nonmanual" "Upper manual"    
"Lower manual"
[5] "Farm"

$OccSon
[1] "Upper nonmanual" "Lower nonmanual" "Upper manual"    
"Lower manual"
[5] "Farm"

abbreviate works here, but gives results that aren't very readable:

 > lapply(lab, abbreviate, 8)

$OccFather
Upper nonmanual Lower nonmanual    Upper manual    Lower 
manual       Farm
      "Upprnnmn"      "Lwrnnmnl"      "Uppermnl"      "Lowermnl" 
   "Farm"

$OccSon
Upper nonmanual Lower nonmanual    Upper manual    Lower manual 
    Farm
      "Upprnnmn"      "Lwrnnmnl"      "Uppermnl"      "Lowermnl" 
   "Farm"

In a related thread, Marc Schwartz proposed a solution for 
wrapping labels, based on

 >short.labels <- sapply(labels, function(x) paste(strwrap(x,

                          10), collapse = "\n"), USE.NAMES = FALSE)

But, my attempt to use strwrap in my context gives a single 
string for each set of dimension names:

 > stack.lab <-function(x) { paste(strwrap(x,10), collapse = 

"\n") }  > lapply(lab, stack.lab) $OccFather [1] 
"Upper\nnonmanual\nLower\nnonmanual\nUpper\nmanual\nLower\nman
ual\nFarm"

$OccSon
[1] 
"Upper\nnonmanual\nLower\nnonmanual\nUpper\nmanual\nLower\nman
ual\nFarm"

For my particular example, I can do what I want with gsub, 
but it is hardly general:

 > lab[[1]] <- gsub(" ","\n", lab[[1]])
 > lab[[2]] <- lab[[1]]   # cheating: I know it's a square table
 > lab

$OccFather
[1] "Upper\nnonmanual" "Lower\nnonmanual" "Upper\nmanual" 
"Lower\nmanual"
[5] "Farm"

$OccSon
[1] "Upper\nnonmanual" "Lower\nnonmanual" "Upper\nmanual" 
"Lower\nmanual"
[5] "Farm"

 > dimnames(xtable) <- lab

Then,
mosaicplot(xtable, shade=TRUE)
gives a nice display!

Can anyone help with a more general solution for wrapping 
labels or abbreviate.or.wrap()?

thanks,
-Michael

-- 
Michael Friendly     Email: friendly at yorku.ca
Professor, Psychology Dept.
York University      Voice: 416 736-5115 x66249 Fax: 416 736-5814
4700 Keele Street    http://www.math.yorku.ca/SCS/friendly.html
Toronto, ONT  M3J 1P3 CANADA