[R-sig-eco] Command pch in lattice package

[tyler]

Manuel Spínola <mspinola at una.ac.cr>
writes:

>
> When I specify the pch=c(1, 3), which are a "dot" and a "+" character,
> the "dot" is assigned to the year 1932 (that appear after year 1931)
> and the "+" is assigned to the year 1931 (that appear first in the
> data frame). Why is that? I though R should assign the first character
> in the vector (pch= c(1, 3)) to the first level in the grouping
> variable (year).

It does. Looking at barley$year reveals that for some reason, 1932 is
the first level, 1931 is the second in that dataset.

Tyler