[R] ylab on secondary y axis

[Francisco J. Zagmutt]

To add on Mark's comments, another neat option to intreractivelly place the 
label in the desired location is to use locator(), i.e:

text( locator(1),"This is Y Axis 2", srt = 270, xpd = TRUE)

Once you execute this command, left click on the desired position for the 
label in the plot and enjoy the results!

Cheers

Francisco


>From: Marc Schwartz <MSchwartz at mn.rr.com>
>Reply-To: MSchwartz at mn.rr.com
>To: Hai Lin <kevinvol2002 at yahoo.com>
>CC: R-Help <r-help at stat.math.ethz.ch>
>Subject: Re: [R] ylab on secondary y axis
>Date: Thu, 09 Jun 2005 11:48:44 -0500
>
>On Thu, 2005-06-09 at 09:26 -0700, Hai Lin wrote:
> > Dear R users:
> >
> > I am trying to add a label on axis(4) but I don't find
> > any reference in R archives. Could you please help me
> > out?
> >
> > Thanks in advance.
> >
> > The followings are the data set and what I have done:
> >
> > Sample data:
> >
> > time	 y1 y2
> > 2	9 24.396
> > 4	7.667 19.082
> > 10	4.667 73.984
> >
> > Commands:
> > plot(time,y1,type='l',col='red',ylab="Relative
> > levels", xlab="Age of Mice",ylim=c(0,20))
> > points(time,y1 col="red", pch=19)
> >
> > op <-par(new=T)
> > plot(time,y2,type='l',
> > col='green',axes=F,xlab="",ylab="", ylim=c(0,80))
> > points(time,y2,col='green',pch=24)
> > axis(4)
>
>There are two options:
>
>First, use:
>
>par(mar = c(5, 4, 4, 5))
>
>before your first plot to increase the margin on the right hand side for
>the second Y axis label. You can further adjust these as you may
>require. See ?par for more information.
>
>
>Then, after the second plot:
>
>1. Use mtext() as follows:
>
>   mtext(4, text = "This is Y Axis 2", line = 3)
>
>Note however that the text is facing outward. Adjust the 'line' argument
>to move the text in or out as you need.
>
>
>
>2. Use text() as follows:
>
>   text(11.5, 40, "This is Y Axis 2", srt = 270, xpd = TRUE)
>
>This enables you to place the text outside the plot region (xpd = TRUE)
>and rotate it so that it is facing inward. Adjust the x and y positions
>as you need.
>
>See ?mtext and ?text for more information.
>
>HTH,
>
>Marc Schwartz
>
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