Default Panel Function for barchart

Default panel function for barchart.

Usage

panel.barchart(x, y, box.ratio = 1, box.width,
               horizontal = TRUE,
               origin = NULL, reference = TRUE,
               stack = FALSE,
               groups = NULL, 
               col = if (is.null(groups)) plot.polygon$col
                     else superpose.polygon$col,
               border = if (is.null(groups)) plot.polygon$border
                        else superpose.polygon$border,
               lty = if (is.null(groups)) plot.polygon$lty
                     else superpose.polygon$lty, 
               lwd = if (is.null(groups)) plot.polygon$lwd
                     else superpose.polygon$lwd,
               ..., identifier = "barchart")

Arguments

x

Extent of Bars. By default, bars start at left of panel, unless origin is specified, in which case they start there.

y

Horizontal location of bars. Possibly a factor.

box.ratio

Ratio of bar width to inter-bar space.

box.width

Thickness of bars in absolute units; overrides box.ratio. Useful for specifying thickness when the categorical variable is not a factor, as use of box.ratio alone cannot achieve a thickness greater than 1.

horizontal

Logical flag. If FALSE, the plot is ‘transposed’ in the sense that the behaviours of x and y are switched. x is now the ‘factor’. Interpretation of other arguments change accordingly. See documentation of bwplot for a fuller explanation.

origin

The origin for the bars. For grouped displays with stack = TRUE, this argument is ignored and the origin set to 0. Otherwise, defaults to NULL, in which case bars start at the left (or bottom) end of a panel. This choice is somewhat unfortuntate, as it can be misleading, but is the default for historical reasons. For tabular (or similar) data, origin = 0 is usually more appropriate; if not, one should reconsider the use of a bar chart in the first place (dot plots are often a good alternative).

reference

Logical, whether a reference line is to be drawn at the origin.

stack

logical, relevant when groups is non-null. If FALSE (the default), bars for different values of the grouping variable are drawn side by side, otherwise they are stacked.

groups

Optional grouping variable.

col, border, lty, lwd

Graphical parameters for the bars. By default, the trellis parameter plot.polygon is used if there is no grouping variable, otherwise superpose.polygon is used. col gives the fill color, border the border color, and lty and lwd the line type and width of the borders.

...

Extra arguments will be accepted but ignored.

identifier

A character string that is prepended to the names of grobs that are created by this panel function.

Details

A barchart is drawn in the panel. Note that most arguments controlling the display can be supplied to the high-level barchart call directly.

See also

barchart

Author

Deepayan Sarkar Deepayan.Sarkar@R-project.org

Examples

barchart(yield ~ variety | site, data = barley,
         groups = year, layout = c(1,6), origin = 0,
         ylab = "Barley Yield (bushels/acre)",
         scales = list(x = list(abbreviate = TRUE,
                                minlength = 5)))