check.for.columns

must.have

<p>Stop if a data.frame does not have some columns.</p>

An extensible framework
for automatically placing direct labels onto multicolor 'lattice' or
'ggplot2' plots.
Label positions are described using Positioning Methods
which can be re-used across several different plots.
There are heuristics for examining "trellis" and "ggplot" objects
and inferring an appropriate Positioning Method.

Toby Hocking

check.for.columns: check for columns

Description

Usage

Arguments