key_group: Group keys
In legendry: Extended Legends and Axes for 'ggplot2'

key_group

R Documentation

Group keys

Description

These functions are helper functions for working with grouped data as keys in guides. They all share the goal of creating a guide key, but have different methods.

key_group_split() is a function factory whose functions make an attempt to infer groups from the scale's labels.
key_group_lut() is a function factory whose functions use a look up table to sort out group membership.

Usage

key_group_split(sep = "[^[:alnum:]]+", reverse = FALSE)

key_group_lut(members, group, ungrouped = "Other")

Arguments

`sep`	A `⁠<character[1]>⁠` giving a regular expression to use for splitting labels provided by the scale using the `strsplit()` function. By defaults, labels are splitted on any non-alphanumeric character.
`reverse`	A `⁠<logical[1]>⁠` which if `FALSE` (default) treats the first part of the split string as groups and later parts as members. If `TRUE`, treats the last part as groups.
`members`	A vector including the scale's `breaks` values.
`group`	A vector parallel to `members` giving the group of each member.
`ungrouped`	A `⁠<character[1]>⁠` giving a group label to assign to the scale's `breaks` that match no values in the `members` argument.

Value

A function to use as the key argument in a guide.

Examples

# Example scale
values <- c("group A:value 1", "group A:value 2", "group B:value 1")
template <- scale_colour_hue(limits = values)

# Treat the 'group X' part as groups
key <- key_group_split(sep = ":")
key(template)

# Treat the 'value X' part as groups
key <- key_group_split(sep = ":", reverse = TRUE)
key(template)

# Example scale
template <- scale_colour_hue(limits = msleep$name[c(1, 7, 9, 23, 24)])

# A lookup table can have more entries than needed
key <- key_group_lut(msleep$name, msleep$order)
key(template)

# Or less entries than needed
key <- key_group_lut(
  msleep$name[23:24], msleep$order[23:24],
  ungrouped = "Other animals"
)
key(template)

legendry documentation built on April 4, 2025, 2:12 a.m.