plot() axis problem

The example uses a rather artificial dataset, neatly divided into
monotonically increasing low and high values.  Any permutation of those
values that did not fall into that pattern would render the question
meaningless.  For example, try

The example I posted was artificial because my real example had 10,000
pts and I didn't want to post that. Basically I wanted to look at the
region surrounding one frequency of the spectrum where I expected a peak.
I couldn't see the peak because plot() had used the whole set of data to
pick the range for the y-axis.

There was of course a nice peak but it was invisible because this peak was
maybe 1/1000 as high as the maximum peak in the whole spectrum.

I think the present behavior of plot() is pretty sensible.

If you look around at other plotting programs out there I think you'll see
some doing what I propose. I think if you use small datasets the current
plot() behaviour will not cause problems. It's only a pain once you start
zooming in on small stretches.