ggsubset: Passing a subset of data to ggplot2 layers.
Description
This is a convenience function to allow layer objects, such as geoms, to take
a subset of the data in the main ggplot() call, without storing a
duplicate of the subset in the ggplot object.
Usage
ggsubset(rowtest = NULL, omit = NULL)
Value
A function that takes a data.frame as argument and returns a
subset of that data.frame according to rowtest
Arguments
rowtest
logical expression indicating which rows to keep.
omit
a character column name to exclude.
Details
ggsubset is a wrapper around subset.data.frame where
the subset argument is set to rowtest and the select
argument to -omit. Since the data argument in the
layer() function can take a function with one argument, we can pass
the function returned from ggsubset as that argument to subset the
data by rows.