Actually this works beautifully as it stands:
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[-length(zz)], zz[-1], SIMPLIFY=FALSE)
y <- rnorm(40)
x0 <- cut(y, breaks=breaks)
plot(x0, y, xaxt="n")
axis(1, at=1:3, labels=as.expression(lbl))
Thanks, Peter.
John Maindonald email: [EMAIL PROTECTED]
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.
On 31 Dec 2007, at 12:35 PM, Peter Dalgaard wrote:
> 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 Øster Farimagsgade 5, Entr.B
> c/ /'_ --- Dept. of Biostatistics PO Box 2099, 1014 Cph. K
> (*) \(*) -- University of Copenhagen Denmark Ph: (+45)
> 35327918
> ~~~~~~~~~~ - ([EMAIL PROTECTED]) FAX: (+45)
> 35327907
>
>
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