R help - May 2009 - Changing point color/character in qqmath

Having solved this problem, I am posting this so that the next time I search
for how to do this I will find an answer...

Using qqmath(..., groups=num) creates a separate qq distribution for each
group (within a panel).  Using the 'col' or 'pch' argument does
not
(usually) work because panel.qqmath sorts the data (but not 'col' or
'pch')
before plotting.  Sorting the data before calling qqmath will ensure that
the sorting does not change the order of the data.

For example, to obtain one distribution per voice part and color the point
by part 1 or part 2:

library(lattice)
singer <- singer
singer <- singer[order(singer$height),]
singer$part <- factor(sapply(strsplit(as.character(singer$voice.part), split
= " "), "[", 1),
         levels = c("Bass", "Tenor", "Alto",
"Soprano"))
singer$num <- factor(sapply(strsplit(as.character(singer$voice.part), split
= " "), "[", 2))
qqmath(~ height | part, data = singer,
       col=singer$num,
       layout=c(4,1))



Kevin

	[[alternative HTML version deleted]]

Thanks to Deepayan, I have a corrected version of how to color points in a
qqmath plot according to another variable.  Using the barley data for a more
concise example::

qqmath(~ yield | variety, data = barley, groups=year,
       auto.key=TRUE,
      prepanel = function(x, ...) {
          list(xlim = range(qnorm(ppoints(length(x)))))
      },
      panel = function(x, ...) {
          xx <- qnorm(ppoints(length(x)))[order(x)]
          panel.xyplot(x = xx, y = x, ...)
      })


The example I posted previously (and shown below) is not correct.  My
apologies.

Kevin

On Wed, May 27, 2009 at 11:05 AM, Kevin W <kw.statr@gmail.com> wrote:
> Having solved this problem, I am posting this so that the next time I
> search for how to do this I will find an answer...
>
> Using qqmath(..., groups=num) creates a separate qq distribution for each
> group (within a panel).  Using the 'col' or 'pch' argument
does not
> (usually) work because panel.qqmath sorts the data (but not 'col'
or 'pch')
> before plotting.  Sorting the data before calling qqmath will ensure that
> the sorting does not change the order of the data.
>
> For example, to obtain one distribution per voice part and color the point
> by part 1 or part 2:
>
> library(lattice)
> singer <- singer
> singer <- singer[order(singer$height),]
> singer$part <- factor(sapply(strsplit(as.character(singer$voice.part),
> split = " "), "[", 1),
>          levels = c("Bass", "Tenor", "Alto",
"Soprano"))
> singer$num <- factor(sapply(strsplit(as.character(singer$voice.part),
split
> = " "), "[", 2))
> qqmath(~ height | part, data = singer,
>        col=singer$num,
>        layout=c(4,1))
>
>
>
> Kevin
>
>
	[[alternative HTML version deleted]]