# [R] can I add to a plot and auto-re-scale axes?

Duncan Murdoch dmurdoch at pair.com
Mon Oct 1 13:34:26 CEST 2001

```On Sun, 30 Sep 2001 22:06:47 -0400 (EDT), you wrote:

>(I'm new to R)
>
>Is there a way to add data to an existing plot, and have the plot axes
>rescaled automatically (i.e. if the new data lie outside the current
>axes) ?

No, there's not.  The scale is established by the first call.
>
>If not, how can I specify multiple datasets at once, so the axes are
>scaled to accomodate all sets?

You need to use the optional arguments xlim and ylim in the first
call.

Your example would look like this:

plot(expts\$x[[1]], expts\$y[[1]], xlim = range(c(expts\$x[[1]],
expts\$x[[4]], expts\$x[[7]])),
ylim = range(c(expts\$y[[1]], expts\$y[[4]], expts\$y[[7]])))

(You might make do with something much simpler, like xlim = c(0,10),
if you know the range of the data in advance, or want consistency
across a wider range.)

You also asked whether your data was organized well.  I'd suggest not
using a list, just use single x and y vectors, with another vector
giving the experiment number.  Then you could have something like

plot(x[expt == 1], y[expt == 1], xlim = range(x[expt %in% c(1,4,
7)]), ylim = range(y[expt %in% c(1,4, 7)])

etc.

Duncan Murdoch
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```