R: Put Strips on the Boundary of a Lattice Display

useOuterStrips {latticeExtra} | R Documentation

## Put Strips on the Boundary of a Lattice Display

### Description

Try to update a `"trellis"` object so that strips are only shown on the top and left boundaries when printed, instead of in every panel as is usual. This is only meaningful when there are exactly two conditioning variables.

### Usage

    useOuterStrips(x,
                   strip = strip.default,
                   strip.left = strip.custom(horizontal = FALSE),
                   strip.lines = 1,
                   strip.left.lines = strip.lines)

### Arguments

`x` | An object of class `"trellis"`.
`strip, strip.left` | A function, character string or logical that would be appropriate `strip` and `strip.left` arguments respectively in a high level lattice function call (see `xyplot`)
`strip.lines, strip.left.lines` | height of strips in number of lines; helpful for multi-line text or mathematical annotation in strips.

### Details

`useOuterStrips` modifies a `"trellis"` object with `length(dim(x)) == 2` so that when plotted, strips are only shown on the top and left boundaries of the panel layout, rather than on top of every panel, as is the usual behaviour.

If the original `"trellis"` object `x` includes non-default `strip` and `strip.left` arguments, they will be ignored. To provide customized strip behaviour, specify the custom strip functions directly as arguments to `useOuterStrips`.

### Value

An object of class `"trellis"`; essentially the same as `x`, but with certain properties modified.

### Author(s)

Deepayan Sarkar

### See Also

`Lattice`, `xyplot`

### Examples

    library(lattice)

    mtcars$HP <- equal.count(mtcars$hp)

    useOuterStrips(xyplot(mpg ~ disp | HP + factor(cyl), mtcars))

    useOuterStrips(xyplot(mpg ~ disp | factor(cyl) + HP, mtcars),
                   strip.left = FALSE,
                   strip = strip.custom(style = 4))

[Package latticeExtra version 0.6-28 Index]