lattice (version 0.12-9)

update.trellis: Retrieve and Update Trellis Object

Description

Update method for objects of class "trellis", and a way to retrieve the last printed trellis object (that was saved).

Usage

## S3 method for class 'trellis':
update(object,
       panel,
       aspect,
       as.table,
       between,
       key,
       auto.key,
       legend,
       layout,
       main,
       page,
       par.strip.text,
       prepanel,
       scales,
       skip,
       strip,
       sub,
       xlab,
       xlim,
       ylab,
       ylim,
       par.settings,
       index.cond,
       perm.cond,
       \dots)
## S3 method for class 'trellis':
t(x)
## S3 method for class 'trellis':
[(x, i, j, \dots, drop = FALSE)
trellis.last.object(warn = TRUE, ...)
trellis.last.object()

Value

An object of class trellis, by default plotted by print.trellis. trellis.last.object returns NULL is no saved object is available.

Details

All the high level lattice functions such as xyplot produce an object of (S3) class "trellis", which is usually printed by its print method. However, the object itself can be manipulated and modified to a large extent using the update method, and then re-plotted as needed.

Most arguments to high level functions can also be supplied to the update method as well, with some exceptions. Generally speaking, anything that would needs to change the data within each panel is a no-no (this includes the formula, data, groups, subscripts and subset). Everything else is technically game, though might not be implemented yet. If you find something missing that you wish to have, feel free to make a request.

Not all arguments accepted by a Lattice function are processed by update, but the following should work (they are described in the help page for xyplot):

panel, aspect, as.table, between, key, auto.key, legend, layout, main, page, par.strip.text, prepanel, scales, skip, strip, sub, xlab, xlim, ylab, ylim, par.settings, index.cond, perm.cond

Any other argument is added to the list of arguments to be passed to the panel function. Because of their somewhat special nature, updates to objects produced by cloud and wireframe do not work very well yet.

The "[" method is a convenient shortcut for updating index.cond. The t method is a convenient shortcut for updating perm.cond in the special (but frequent) case where there are exactly two conditioning variables, when it has the effect of switching (transposing) their order.

The print method for "trellis" objects optionally saves the object after printing it. If this feature is on, trellis.last.object can retrieve it. Note that at most one object can be saved at a time. If trellis.last.object is called with arguments, these are used to update the retrieved object before returning it.

See Also

trellis.object, Lattice, xyplot

Examples

spots <- by(sunspots, gl(235, 12, lab = 1749:1983), mean)
old.options <- lattice.options(save.object = TRUE)
xyplot(spots ~ 1749:1983, xlab = "", type = "l",
       scales = list(x = list(alternating = 2)),
       main = "Average Yearly Sunspots")
update(trellis.last.object(), aspect = "xy")
trellis.last.object(xlab = "Year")
lattice.options(old.options)