Strange behavior of pretty

Dear all,

I got stuck with a weird behavior of pretty:
    pretty(c(-1,1),n=1)
yields -2, 0, 2 instead of the desired result -1 1.
Likewise, 
    pretty(c(-2,2),n=1)
yields -5, 0, 5 instead of the desired result -2 2.

With n=0, the result is the same, while with n=2 everything is as
documented.

This behavior nastily messed up some of my cube plots. Is there any chance
that this can be fixed? 

On 03/11/2007 4:34 PM, Ulrike Gr?mping wrote:

Dear all,

I got stuck with a weird behavior of pretty:
    pretty(c(-1,1),n=1)
yields -2, 0, 2 instead of the desired result -1 1.
Likewise,
    pretty(c(-2,2),n=1)
yields -5, 0, 5 instead of the desired result -2 2.

I don't think pretty() should ever return -1 1 or -2 2.  It should
always return multiples of some round number, so it would have to
include 0.  But I don't see why it is expanding the range.  It doesn't
do that when the results are non-negative, e.g.

pretty(0:1, n=1)

[1] 0 1

pretty(0:2, n=1)

[1] 0 2

With n=0, the result is the same, while with n=2 everything is as
documented.

This behavior nastily messed up some of my cube plots. Is there any chance
that this can be fixed?

The documentation has been sitting for 8 years with "FIXME" notes in it,
so I wouldn't hold my breath.