legendry (version 0.2.1)

key_group: 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")

Value

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

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.

See Also

Other keys: key_range, key_segments, key_specialty, key_standard

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)