get_guide_data {ggplot2} | R Documentation |
Extract tick information from guides
Description
get_guide_data()
builds a plot and extracts information from guide keys. This
information typically contains positions, values and/or labels, depending
on which aesthetic is queried or guide is used.
Usage
get_guide_data(plot = last_plot(), aesthetic, panel = 1L)
Arguments
plot |
A |
aesthetic |
A string that describes a single aesthetic for which to
extract guide information. For example: |
panel |
An integer giving a panel number for which to return position guide information. |
Value
One of the following:
A
data.frame
representing the guide key, when the guide is unique for the aesthetic.A
list
when the coord does not support position axes or multiple guides match the aesthetic.-
NULL
when no guide key could be found.
Examples
# A standard plot
p <- ggplot(mtcars) +
aes(mpg, disp, colour = drat, size = drat) +
geom_point() +
facet_wrap(vars(cyl), scales = "free_x")
# Guide information for legends
get_guide_data(p, "size")
# Note that legend guides can be merged
merged <- p + guides(colour = "legend")
get_guide_data(merged, "size")
# Guide information for positions
get_guide_data(p, "x", panel = 2)
# Coord polar doesn't support proper guides, so we get a list
polar <- p + coord_polar()
get_guide_data(polar, "theta", panel = 2)
[Package ggplot2 version 3.5.1 Index]