From: Martin Maechler <maechler_at_stat.math.ethz.ch>

Date: Fri 01 Jul 2005 - 22:57:42 EST

ss <- lapply(seq(along = at),

}

R-help@stat.math.ethz.ch mailing list

https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Fri Jul 01 23:04:38 2005

Date: Fri 01 Jul 2005 - 22:57:42 EST

Gabor> On 6/29/05, Jing Shen <jshen6@gmail.com> wrote:

>> I am planning to plot my data on log scale (y-axis). There is a

* >> parameter in plot function, which is
** >> plot( ..., log="y", ...)
** >> While, the problem is that it is with base of e. Is there a way to let
** >> me change it to 10 instead of e?
** >>
*

Gabor> Is your question how to get the axis labels to be powers of 10? Gabor> In that case,

Gabor> plot(1:100, log = "y", yaxt = "n") # do not show y axis Gabor> axis(2, c(1,10,100)) # draw y axis with required labels

and if you're there, you might be interested in the following which provides a somewhat automated way to show "a * 10 ^ k" tick-labels instead of the scientific "a e k" ones. { For some time, I had wanted that something like this could become an easy option for builtin axis(*), but then I also know that we should rather strive to build future-proof tools, which "hence" should we applicable to 'grid' as well as to old-style 'graphics' and all this got me stuck in the process ... }

Martin Maechler, ETH Zurich

axTexpr <- function(side, at = axTicks(side, axp=axp, usr=usr, log=log),

axp = NULL, usr = NULL, log = NULL){

## Purpose: Do "a 10^k" labeling instead of "a e<k>" ## this auxiliary should return 'at' and 'label' (expression) ## ---------------------------------------------------------------------- ## Arguments: as for axTicks() ## ---------------------------------------------------------------------- ## Author: Martin Maechler, Date: 7 May 2004, 18:01 eT <- floor(log10(abs(at)))# at == 0 case is dealt with belowmT <- at / 10^eT

ss <- lapply(seq(along = at),

function(i) if(at[i] == 0) quote(0) else substitute(A %*% 10^E, list(A=mT[i], E=eT[i])))do.call("expression", ss)

}

par(mar=.1+c(5,5,4,1))## << For the horizontal y-axis labels, need more space
plot(x,y, axes= FALSE, frame=TRUE)

aX <- axTicks(1); axis(1, at=aX, label= axTexpr(1, aX))
if(FALSE) # rather the next one

{ aY <- axTicks(2); axis(2, at=aY, label= axTexpr(2, aY))}
## or rather (horizontal labels on y-axis):
aY <- axTicks(2); axis(2, at=aY, label= axTexpr(2, aY), las=2)

R-help@stat.math.ethz.ch mailing list

https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Fri Jul 01 23:04:38 2005

*
This archive was generated by hypermail 2.1.8
: Fri 03 Mar 2006 - 03:33:08 EST
*