R help - Dec 2013 - plus/minus +/- in factor; not plotmath not expression

I want to put the "plus or minus" symbol into a character variable, so
that this can be turned into a factor and be displayed in the "strip"
of a faceted ggplot2 plot.

A very nice solution, thanks to Professor Ripley's post of Nov 16, 2008;
3:13pm, visible at
http://r.789695.n4.nabble.com/Symbols-to-use-in-text-td874239.html and
subsequently http://www.fileformat.info/info/unicode/char/00b1/index.htm, is:

junk<- "\u00B1"
print(junk)

#	This works very nicely. For instance:

junk<-data.frame(gug=c(
 	rep( "\u00B1 1.2", 10)
 		,
 	rep( "\u00B1 2.3", 10)
 	)
)
junk$eks<-1:nrow(junk)
junk$why<-with(junk, as.numeric(gug) + eks)
print(summary(junk))
library(ggplot2)
print(
 	ggplot(data=junk, mapping=aes(x=eks, y=why))
 	+ geom_point()
 	+ facet_grid(. ~ gug)
)

This works very nicely on my system, but I just wanted to enquire:

Is this machine-independent and stable?

Is there a "native R" way to do this?

I did this in:
> sessionInfo()
R version 2.15.3 (2013-03-01)
Platform: x86_64-apple-darwin9.8.0/x86_64 (64-bit)

locale:
[1] en_US.UTF-8/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base

other attached packages:
[1] ggplot2_0.9.3.1

loaded via a namespace (and not attached):
  [1] colorspace_1.2-0   dichromat_1.2-4    digest_0.6.0       grid_2.15.3      
gtable_0.1.2       labeling_0.1
  [7] MASS_7.3-23        munsell_0.4        plyr_1.8           proto_0.3-10     
psych_1.2.8        RColorBrewer_1.0-5
[13] reshape2_1.2.2     scales_0.2.3       stringr_0.6.2
>
Incidentally (and for the sake of keyword searches): Although a google search
initially led me to posts about expression() and plotmath, those eventually had
nothing to do with the solution.

Jacob A. Wegelin
Assistant Professor
Department of Biostatistics
Virginia Commonwealth University
830 E. Main St., Seventh Floor
P. O. Box 980032
Richmond VA 23298-0032
U.S.A. 
CTSA grant: UL1TR000058
URL: http://www.people.vcu.edu/~jwegelin

On 02/12/2013 2:22 PM, Jacob Wegelin wrote:
> I want to put the "plus or minus" symbol into a character
variable, so that this can be turned into a factor and be displayed in the
"strip" of a faceted ggplot2 plot.
>
> A very nice solution, thanks to Professor Ripley's post of Nov 16,
2008; 3:13pm, visible at
http://r.789695.n4.nabble.com/Symbols-to-use-in-text-td874239.html and
subsequently http://www.fileformat.info/info/unicode/char/00b1/index.htm, is:
>
> junk<- "\u00B1"
> print(junk)
>
> #	This works very nicely. For instance:
>
> junk<-data.frame(gug=c(
>   	rep( "\u00B1 1.2", 10)
>   		,
>   	rep( "\u00B1 2.3", 10)
>   	)
> )
> junk$eks<-1:nrow(junk)
> junk$why<-with(junk, as.numeric(gug) + eks)
> print(summary(junk))
> library(ggplot2)
> print(
>   	ggplot(data=junk, mapping=aes(x=eks, y=why))
>   	+ geom_point()
>   	+ facet_grid(. ~ gug)
> )
>
> This works very nicely on my system, but I just wanted to enquire:
>
> Is this machine-independent and stable?
It is machine-independent and stable because \u00B1 means "Unicode 
PLUS-MINUS SIGN", but it is not device-independent.  There may be a 
graphics device that does not support all Unicode characters.   I'd 
guess it is pretty widely available though.
>
> Is there a "native R" way to do this?
That is native R.

Duncan Murdoch
>
> I did this in:
>
> > sessionInfo()
> R version 2.15.3 (2013-03-01)
> Platform: x86_64-apple-darwin9.8.0/x86_64 (64-bit)
>
> locale:
> [1] en_US.UTF-8/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8
>
> attached base packages:
> [1] stats     graphics  grDevices utils     datasets  methods   base
>
> other attached packages:
> [1] ggplot2_0.9.3.1
>
> loaded via a namespace (and not attached):
>    [1] colorspace_1.2-0   dichromat_1.2-4    digest_0.6.0       grid_2.15.3
gtable_0.1.2       labeling_0.1
>    [7] MASS_7.3-23        munsell_0.4        plyr_1.8          
proto_0.3-10       psych_1.2.8        RColorBrewer_1.0-5
> [13] reshape2_1.2.2     scales_0.2.3       stringr_0.6.2
> >
>
> Incidentally (and for the sake of keyword searches): Although a google
search initially led me to posts about expression() and plotmath, those
eventually had nothing to do with the solution.
>
> Jacob A. Wegelin
> Assistant Professor
> Department of Biostatistics
> Virginia Commonwealth University
> 830 E. Main St., Seventh Floor
> P. O. Box 980032
> Richmond VA 23298-0032
> U.S.A.
> CTSA grant: UL1TR000058
> URL: http://www.people.vcu.edu/~jwegelin
>
> ______________________________________________
> R-help at r-project.org 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.

On Dec 2, 2013, at 11:22 AM, Jacob Wegelin wrote:
> 
> I want to put the "plus or minus" symbol into a character
variable, so that this can be turned into a factor and be displayed in the
"strip" of a faceted ggplot2 plot.
> 
> A very nice solution, thanks to Professor Ripley's post of Nov 16,
2008; 3:13pm, visible at
http://r.789695.n4.nabble.com/Symbols-to-use-in-text-td874239.html and
subsequently http://www.fileformat.info/info/unicode/char/00b1/index.htm, is:
> 
> junk<- "\u00B1"
> print(junk)
> 
> #	This works very nicely. For instance:
> 
snipped code
> 
> This works very nicely on my system, but I just wanted to enquire:
> 
> Is this machine-independent and stable?
It is font-_dependent_. It displays fine on a Mac console if that's any
help, but it seems you probably already know that. I tested it on a 2.15.3
version of R on a Windows XP machine which probably has the default font
settings for that ancient OS and it displayed fine there, too. It really depends
on whether the default font for you OS has a glyph in that position in its font
table.
> 
> Is there a "native R" way to do this?
> 
> I did this in:
> 
>> sessionInfo()
> R version 2.15.3 (2013-03-01)
> Platform: x86_64-apple-darwin9.8.0/x86_64 (64-bit)
>> 
> 
> Incidentally (and for the sake of keyword searches): Although a google
search initially led me to posts about expression() and plotmath, those
eventually had nothing to do with the solution.
That's not entirely true. The links on the ?plotmath page in the "Other
symbols" section send you to ?points which has very instructive examples. I
keep an annotated version of the output of TestChars(font=5) on the side of my
desktop machine.

TestChars <- function(sign = 1, font = 1, ...)
{
   MB <- l10n_info()$MBCS
   r <- if(font == 5) { sign <- 1; c(32:126, 160:254)
       } else if(MB) 32:126 else 32:255
   if (sign == -1) r <- c(32:126, 160:255)
   par(pty = "s")
   plot(c(-1,16), c(-1,16), type = "n", xlab = "", ylab =
"",
        xaxs = "i", yaxs = "i",
        main = sprintf("sign = %d, font = %d", sign, font))
   grid(17, 17, lty = 1) ; mtext(paste("MBCS:", MB))
   for(i in r) try( points(i%%16, i%/%16, pch = sign*i, font = font,...))
   for(i in r) try( text( (i%%16)-0.2, (i%/%16)-0.2,  as.character(i), font = 1,
cex=0.5))
}

TestChars(font = 5)

You can see on that graphic that "?" is 177
and:
> strtoi(0x00B1)
[1] 177
> as.hexmode(177)
[1] "b1

-- 
David.
> 
> Jacob A. Wegelin

David Winsemius
Alameda, CA, USA