lattice (version 0.20-45)

C_06_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 trellis
update(object,
       panel,
       aspect,
       as.table,
       between,
       key,
       auto.key,
       legend,
       layout,
       main,
       page,
       par.strip.text,
       prepanel,
       scales,
       skip,
       strip,
       strip.left,
       sub,
       xlab,
       ylab,
       xlab.top,
       ylab.right,
       xlim,
       ylim,
       xscale.components,
       yscale.components,
       axis,
       par.settings,
       plot.args,
       lattice.options,
       index.cond,
       perm.cond,
       ...)
# S3 method for trellis
t(x)
# S3 method for trellis
[(x, i, j, ..., drop = FALSE)
trellis.last.object(..., prefix)

Value

An object of class trellis, by default plotted by

print.trellis. trellis.last.object returns

NULL is no saved object is available.

Arguments

object, x

The object to be updated, of class "trellis".

i, j

indices to be used. Names are not currently allowed.

drop

logical, whether dimensions with only one level are to be dropped. Currently ignored, behaves as if it were FALSE.

panel, aspect, as.table, between, key, auto.key, legend, layout, main, page, par.strip.text, prepanel, scales, skip, strip, strip.left, sub, xlab, ylab, xlab.top, ylab.right, xlim, ylim, xscale.components, yscale.components, axis, par.settings, plot.args, lattice.options, index.cond, perm.cond, ...

arguments that will be used to update object. See details below.

prefix

A character string acting as a prefix identifying the plot of a "trellis" object. Only relevant when a particular page is occupied by more than one plot. Defaults to the value appropriate for the last "trellis" object printed. See trellis.focus.

Author

Deepayan Sarkar

Details

All high level lattice functions such as xyplot produce an object of (S3) class "trellis", which is usually displayed by its print method. However, the object itself can be manipulated and modified to a large extent using the update method, and then re-displayed 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 ones listed above should work. The purpose of these arguments are described in the help page for xyplot. 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 enabled, trellis.last.object can retrieve it. By default, the last object plotted is retrieved, but if multiple objects are plotted on the current page, then others can be retrieved using the appropriate prefix argument. 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, labels = 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)