key: Generate Dichotomous Key using CONFOR/KEY

In RDelta: Parse and Query DELTA-Format Taxonomic Descriptions

Generate Dichotomous Key using CONFOR/KEY

Description

This function replicates the KEY command in the DELTA system for generating dichotomous keys. It creates the necessary directives files and runs the CONFOR and KEY programs.

Usage

key(
  delta,
  heading = NULL,
  add_character_numbers = FALSE,
  no_bracketted_key = FALSE,
  no_tabular_key = TRUE,
  number_of_confirmatory_characters = 0,
  treat_characters_as_variable = NULL,
  use_normal_values = NULL,
  character_reliabilities = NULL,
  key_states = NULL,
  abase = 2,
  rbase = 1.4,
  reuse = 1.01,
  varywt = 0.8,
  print_width = 80,
  exclude_items = NULL,
  exclude_characters = NULL,
  remove_temp = TRUE
)

Arguments

delta	A Delta dataset object (created by load_delta)
heading	Heading for the output (default = NULL, uses heading from specs file)
add_character_numbers	Character numbers are to be inserted in bracketed keys (default = FALSE)
no_bracketted_key	Suppresses the production of a key in the conventional, 'bracketed' format (default = FALSE)
no_tabular_key	Suppresses the production of a key in tabular format (default = TRUE)
number_of_confirmatory_characters	Number of confirmatory characters that will be sought for each main character in the key (default = 0, maximum = 4)
treat_characters_as_variable	A list of characters for which particular attributes are to be treated as 'variable' (default = NULL)
use_normal_values	A list of numeric characters for which extreme values are to be ignored and normal values used when translating into other formats (default = NULL)
character_reliabilities	A list of the 'reliabilities' of the characters (default = NULL)
key_states	A list of numeric character states to be divided into ranges for use as states in identification keys (default = NULL)
abase	Sets the base of the logarithmic item abundance scale (default = 2)
rbase	Sets the base of the logarithmic character-reliability scale (default = 1.4)
reuse	Attempt to minimize the number of different characters used in the key (default = 1.01)
varywt	Sets the value of a parameter that determines the treatment of intra-taxon variability in the process of character selection (default = 0.8)
print_width	Maximum line length for output of the keys (default = 80)
exclude_items	A list of items to be excluded (default = NULL)
exclude_characters	A list of characters to be excluded (default = NULL)
remove_temp	Logical; if TRUE, remove temporary files after conversion (default = TRUE)

Details

The function assumes that the CONFOR and KEY program executables are available in the system PATH or in the current working directory.

Value

Invisibly returns the key as a character vector on success

Examples

# Requires the CONFOR and KEY executables on the PATH.

try({
  delta <- load_delta(
    system.file("extdata", "chars_viola", package = "RDelta"),
    system.file("extdata", "items_viola", package = "RDelta"),
    system.file("extdata", "specs_viola", package = "RDelta")
  )
  key(delta)
  key(delta, abase = 2, rbase = 1.4,
      no_tabular_key = TRUE, number_of_confirmatory_characters = 2)
})

RDelta documentation built on Oct. 28, 2026, 5:12 p.m.