These functions assist with mapping between scale degrees, notes and chords.
Usage
scale_degree(
notes,
key = "c",
scale = "diatonic",
use_root = TRUE,
strict_accidentals = TRUE,
naturalize = FALSE,
roman = FALSE
)
scale_note(deg, key = "c", scale = "diatonic", collapse = FALSE, ...)
note_in_scale(
notes,
key = "c",
scale = "diatonic",
use_root = TRUE,
strict_accidentals = TRUE
)
chord_degree(
notes,
key = "c",
scale = "diatonic",
strict_accidentals = TRUE,
naturalize = FALSE,
roman = FALSE
)
is_in_scale(notes, key = "c", scale = "diatonic", strict_accidentals = TRUE)Arguments
- notes
character, a string of notes.
- key
character, key signature (or root note) for scale, depending on the type of
scale.- scale
character, the suffix of a supported
scale_*function.- use_root
logical, use lowest pitch in chord. Otherwise yield an
NAin output.- strict_accidentals
logical, whether representation must match key and scale. See details.
- naturalize
logical, whether to naturalize any sharps or flats before obtaiuning the scale degree.
- roman
logical, return integer scale degrees as Roman numerals.
- deg
integer, roman class, or character roman, the scale degree.
- collapse
logical, collapse result into a single string ready for phrase construction.
- ...
additional arguments passed to the scale function, e.g.,
sharp = FALSEforscale_chromatic().
Details
Obtain the scale degree of a note in a supported scale with scale_degree().
This function works on any noteworthy string. It ignores octave numbering.
Rests and any note not explicitly in the scale return NA. If deg is
greater than the number of degrees in the scale, it is recycled, e.g., in C
major 8 starts over as C.
By default, flats and sharps checked strictly against the scale. Setting
strict_accidentals = FALSE will convert any flats or sharps present,
if necessary based on the combination of key signature and
scale. The chromatic scale is a special case where strict accidental
is always ignored.
Not any arbitrary combination of valid key and valid scale is valid. For
example, key = "am" and scale = "harmonic" is valid, but not with
key = "a".
note_in_scale() is a wrapper around scale_degree(). To check if full
chords are diatonic to the scale, see is_diatonic().
The inverse of scale_degree() is scale_note(), for obtaining the note
associated with a scale degree. This could be done simply by calling a
scale_* function and indexing its output directly, but this wrapper is
provided to complement scale_degree().
Additionally, it accepts the common Roman numeral input for the degree.
This can be with the roman class or as a character string.
Degrees return NA if outside the scale degree range.
Examples
scale_degree("r c, e3 g~ g s g# ceg")
#> [1] NA 1 3 5 5 NA NA 1
note_in_scale("r c, e3 g~ g s g# ceg")
#> [1] NA TRUE TRUE TRUE TRUE NA FALSE TRUE
scale_degree("c e g", roman = TRUE)
#> [1] I III V
scale_degree("c c# d_ e", key = "d")
#> [1] NA 7 NA 2
scale_degree("c c# d_ e", key = "d", strict_accidentals = FALSE)
#> [1] NA 7 7 2
scale_degree("c, e_3 g' f#ac#", use_root = FALSE)
#> [1] 1 NA 5 NA
scale_degree("c, e_3 g' f#ac#", naturalize = TRUE) # lowest chord pitch: c#
#> [1] 1 3 5 1
scale_degree("c# d_ e_' e4 f f# g", key = "c#", scale = "chromatic")
#> [1] 1 1 3 4 5 6 7
scale_note(1:3, key = "am")
#> <Noteworthy string>
#> Format: vectorized time
#> Values: a b c
scale_note(c(1, 3, 8), "d", collapse = TRUE)
#> <Noteworthy string>
#> Format: space-delimited time
#> Values: d f# d
all(sapply(list(4, "IV", as.roman(4)), scale_note) == "f")
#> [1] TRUE
x <- "d dfa df#a f#ac#"
chord_degree(x, "d")
#> [[1]]
#> [1] 1
#>
#> [[2]]
#> [1] 1 NA 5
#>
#> [[3]]
#> [1] 1 3 5
#>
#> [[4]]
#> [1] 3 5 7
#>
is_in_scale(x, "d")
#> [1] TRUE FALSE TRUE TRUE