[R] Mathematical annotation in lattice strip: Is it possible?

[Deepayan Sarkar]

On 5/12/08, Andrewjohnclose <a.j.close at ncl.ac.uk> wrote:
>
>  I have tried without success to find a way including the square root symbol
>  in lattice strips as part of my conditioning labels. I have tried
>  supplementing by creating a list of vectors using the var.name function
>  coupled with the expression function used in xlab/ylab.
>
>  xyplot(adjusted_Rand_index~cluster|distance_measure, main="Level of
>  agreement between partitions: Wards Method", ylab="Coefficient value
>  (adjusted rand index)", xlab="number of clusters", type="l", data=randA1,
>  strip=strip.custom(varnames=c(expression(sqrt(Bray-Curtis)))

You say 'var.names', but use 'varnames'. ?strip.custom also says:

var.name: vector of character strings or expressions as long as the
          number of conditioning variables.  The contents are
          interpreted as names for the conditioning variables.  Whether
          they are shown on the strip depends on the values of
          'strip.names' and 'style' (see below).  By default, the names
          are shown for shingles, but not for factors.

This seems to work as expected:

xyplot(1 ~ 1 | gl(1, 1),
       strip = strip.custom(var.name = expression(sqrt(Bray-Curtis)),
                            strip.names = TRUE, strip.levels = FALSE))

-Deepayan