[R] alternative to 'groups' for lattice bwplot()

[Deepayan Sarkar]

On Wednesday 23 March 2005 00:10, Sebastian Luque wrote:
> Hi,
>
> Is there some alternative to the 'groups' argument in lattice's
> bwplot function for boxplots? Say in the example below:
>
> bwplot(yield ~ site | year, data = barley)
>
> you want to have two side by side boxplots per site, corresponding to
> each year in the barley data frame. Ideally, the space between
> boxplots of the same site should be smaller than that between
> boxplots of different sites.
>
> This seemed like a job for the 'groups' argument, but panel.bwplot
> doesn't take it. I saw that boxplot() might do this for the
> particular example above, but not for a more complex one with
> additional conditioning variables (as in my actual problem).

I consider bwplot to already provide a grouped display (box plots are 
univariate summaries, and bwplot allows you to display several of them 
together within a panel). What you are looking for may be appropriate 
in certain situations, but is not general enough to warrant a built-in 
implementation. In other words, you'll have to write your own panel 
function.

> I thought I'd find something about this in the archives, but I'm
> either not using the right keywords or the question hasn't come up
> yet.

The only instance I can recall is:

http://tolstoy.newcastle.edu.au/R/help/04/02/0848.html

Deepayan