function can be found in
Variables are specified using lattice specific .
A simple boxplot for infmor
(A single variable specified).
bwplot(infmor) produces the same boxplot if
you have previously issued a attach(world).
span class="code">bwplot() accepts only individual variables (vectors) you
cannot specify a matrix.
li>bwplot(infmor ~ continent, data=world) boxplot by continent
(the categorical variable continent defines the groups)
- bwplot(infmor ~ continent | equal.count(urb,3), data=world)
produce a boxplot for variable infmor by continent
for three distinct levels of urbanization. equal.count(urb,3)
is a lattice function that creates a categorical variable (factor) from a continuous variable, with roughly
the same number of observations. Here three groups are created..
- bwplot(infmor ~ continent | equal.count(urb,3)*equal.count(gnpcap,3), data=world)
adds a second condition (gnpcap GNP/Capita in three groups.
Note that in the example the chart titles contain in addition to the title, the interval covered by the groups using colour.:
bwplot is in fact
an interface to panel.bwplot a function that describes how to produce the
individual graphs. The collection of functions made available offers a very large number of options that
are beyond the scope of this text; let us just say that most of the options are dealing with aesthetical
aspects (colours, styles etc) of the charts or let add titles and labels.