R help - Dec 2007 - Symbolic substitution in parallel; use infinity symbol?

I'd like to be able to modify axlab in (C) below so that 'Inf'
is replaced by the infinity symbol.

y <- rnorm(40)
breaks <- c(-Inf, -1, 1, Inf)
x <- cut(y, breaks=breaks)
plot(unclass(x), y, xaxt="n", xlab="")

## A: The following gives the axis labels "(-Inf, 1]", etc.
axis(1, at=1:3, labels=expression("(-Inf,-1]", "(-1,1]",
"(1, Inf]"))

## B: The following replaces Inf by the infinity symbol
axis(1, at=1:3, labels=expression("(" * -infinity * ", " *
-1 * "]",
                                 "(" * -1 * ", 1]",
"(1, " * infinity
* "]"),
    line=1.25, lty=0)

## C: The following gives the axis labels "(-Inf, 1]", etc.,
## in a more automated manner.
axlab <- lapply(levels(x), function(x)substitute(a, list(a=x)))
# Can alternatively use bquote()
axis(1, at=1:3, labels=as.expression(axlab), line=2.25, lty=0)

However I have been unable to modify axlab so that the infinity
symbol appears in place of 'Inf'.  Is there is some relatively
straightforward way to do this?  The issue is of course more
general than this specific example.

John Maindonald             email: john.maindonald at anu.edu.au
phone : +61 2 (6125)3473    fax  : +61 2(6125)5549
Centre for Mathematics & Its Applications, Room 1194,
John Dedman Mathematical Sciences Building (Building 27)
Australian National University, Canberra ACT 0200.

John Maindonald wrote:
> I'd like to be able to modify axlab in (C) below so that 'Inf'
> is replaced by the infinity symbol.
>
> y <- rnorm(40)
> breaks <- c(-Inf, -1, 1, Inf)
> x <- cut(y, breaks=breaks)
> plot(unclass(x), y, xaxt="n", xlab="")
>
> ## A: The following gives the axis labels "(-Inf, 1]", etc.
> axis(1, at=1:3, labels=expression("(-Inf,-1]",
"(-1,1]", "(1, Inf]"))
>
> ## B: The following replaces Inf by the infinity symbol
> axis(1, at=1:3, labels=expression("(" * -infinity * ",
" * -1 * "]",
>                                  "(" * -1 * ", 1]",
"(1, " * infinity
> * "]"),
>     line=1.25, lty=0)
>
> ## C: The following gives the axis labels "(-Inf, 1]", etc.,
> ## in a more automated manner.
> axlab <- lapply(levels(x), function(x)substitute(a, list(a=x)))
> # Can alternatively use bquote()
> axis(1, at=1:3, labels=as.expression(axlab), line=2.25, lty=0)
>
> However I have been unable to modify axlab so that the infinity
> symbol appears in place of 'Inf'.  Is there is some relatively
> straightforward way to do this?  The issue is of course more
> general than this specific example.
>   
Here's an idea, leaving some tinkering for you:

breaks <- c(-Inf, -1, 1, Inf)

zz <- lapply(breaks, function(x) 
      if(x==-Inf) quote(-infinity) else
      if (x==Inf) quote(infinity) else 
      format(x))

lbl <- mapply(function(x,y)
                 bquote("(" * .(x) * "," * .(y) *
"]"),
              zz[-4], zz[-1], SIMPLIFY=FALSE)


-- 
   O__  ---- Peter Dalgaard             ?ster Farimagsgade 5, Entr.B
  c/ /'_ --- Dept. of Biostatistics     PO Box 2099, 1014 Cph. K
 (*) \(*) -- University of Copenhagen   Denmark          Ph:  (+45) 35327918
~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk)                  FAX: (+45) 35327907

Happy New year John!

 

Is the following what you are looking for:

 

y <- rnorm(40)

breaks <- c(-Inf, -1, 1, Inf)

x <- cut(y, breaks=breaks)

plot(unclass(x), y, xaxt="n", xlab="")

 

leftlab <- expression("(-" * infinity * "]")

rightlab<-  expression("[+" * infinity * ")")

axlab <- levels(x)

axlab[1] <- leftlab

axlab[length(axlab)] <- rightlab

axis(1, at=1:3, labels=axlab, line=2.25, lty=0)

 

Cheers,

 

Bert Gunter

Genentech

 

 

-----Original Message-----

From: r-help-bounces@r-project.org [mailto:r-help-bounces@r-project.org] On
Behalf Of John Maindonald

Sent: Sunday, December 30, 2007 3:45 PM

To: r-help@stat.math.ethz.ch

Subject: [R] Symbolic substitution in parallel; use infinity symbol?

 

 

I'd like to be able to modify axlab in (C) below so that 'Inf'

is replaced by the infinity symbol.

 

y <- rnorm(40)

breaks <- c(-Inf, -1, 1, Inf)

x <- cut(y, breaks=breaks)

plot(unclass(x), y, xaxt="n", xlab="")

 

## A: The following gives the axis labels "(-Inf, 1]", etc.

axis(1, at=1:3, labels=expression("(-Inf,-1]", "(-1,1]",
"(1, Inf]"))

 

## B: The following replaces Inf by the infinity symbol

axis(1, at=1:3, labels=expression("(" * -infinity * ", " *
-1 * "]",

                                 "(" * -1 * ", 1]",
"(1, " * infinity

* "]"),

    line=1.25, lty=0)

 

## C: The following gives the axis labels "(-Inf, 1]", etc.,

## in a more automated manner.

axlab <- lapply(levels(x), function(x)substitute(a, list(a=x)))

# Can alternatively use bquote()

axis(1, at=1:3, labels=as.expression(axlab), line=2.25, lty=0)

 

However I have been unable to modify axlab so that the infinity

symbol appears in place of 'Inf'.  Is there is some relatively

straightforward way to do this?  The issue is of course more

general than this specific example.

 

John Maindonald             email: john.maindonald@anu.edu.au

phone : +61 2 (6125)3473    fax  : +61 2(6125)5549

Centre for Mathematics & Its Applications, Room 1194,

John Dedman Mathematical Sciences Building (Building 27)

Australian National University, Canberra ACT 0200.

 

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