music21.chord

This module defines the Chord object, a subclass of GeneralNote as well as other methods, functions, and objects related to chords.

Chord

class music21.chord.Chord(notes: None | Sequence[Pitch] | Sequence[Note] | Sequence[str] | str | Sequence[int] = None, **keywords)

Class representing Chords.

A Chord functions like a Note object but has multiple pitches.

Create chords by passing a list of strings of pitch names:

>>> dMaj = chord.Chord(['D', 'F#', 'A'])
>>> dMaj
<music21.chord.Chord D F# A>

Pitch names can also include octaves:

>>> dMaj = chord.Chord(['D3', 'F#4', 'A5'])
>>> dMaj
<music21.chord.Chord D3 F#4 A5>

A single string with note names separated by spaces also works:

>>> myChord = chord.Chord('A4 C#5 E5')
>>> myChord
<music21.chord.Chord A4 C#5 E5>

Or you can combine already created Notes or Pitches:

>>> cNote = note.Note('C')
>>> eNote = note.Note('E')
>>> gNote = note.Note('G')

And then create a chord with note objects:

>>> cmaj = chord.Chord([cNote, eNote, gNote])
>>> cmaj  # default octave of 4 is used for these notes, since octave was not specified
<music21.chord.Chord C E G>

Or with pitches:

>>> cmaj2 = chord.Chord([pitch.Pitch('C'), pitch.Pitch('E'), pitch.Pitch('G')])
>>> cmaj2
<music21.chord.Chord C E G>

Chord has the ability to determine the root of a chord, as well as the bass note of a chord. In addition, Chord is capable of determining what type of chord a particular chord is, whether it is a triad or a seventh, major or minor, etc., as well as what inversion the chord is in.

A chord can also be created from pitch class numbers:

>>> c = chord.Chord([0, 2, 3, 5])
>>> c.pitches
(<music21.pitch.Pitch C>,
 <music21.pitch.Pitch D>,
 <music21.pitch.Pitch E->,
 <music21.pitch.Pitch F>)

Or from MIDI numbers:

>>> c = chord.Chord([72, 76, 79])
>>> c.pitches
(<music21.pitch.Pitch C5>, <music21.pitch.Pitch E5>, <music21.pitch.Pitch G5>)

(If the number is < 12, it is assumed to be an octaveless pitch-class number, if above 12, then a MIDI number. To create chords below MIDI 12, create a Pitch object with that MIDI number instead and then pass that to the Chord creator).

Duration or quarterLength also works:

>>> d = duration.Duration(2.0)
>>> myChord = chord.Chord('A4 C#5 E5', duration=d)
>>> myChord
<music21.chord.Chord A4 C#5 E5>
>>> myChord.duration
<music21.duration.Duration 2.0>
>>> myChord.duration is d
True

>>> myChord = chord.Chord('A4 C#5 E5', quarterLength=3.75)
>>> myChord.duration.type
'half'
>>> myChord.duration.dots
3

Chord bases

Chord read-only properties

Chord.chordTablesAddress

Return a four-element ChordTableAddress that represents that raw data location for information on the set class interpretation of this Chord as well as the original pitchClass

The data format is a Forte set class cardinality, index number, and inversion status (where 0 is invariant, and -1 and 1 represent inverted or not, respectively).

>>> c = chord.Chord(['D4', 'F#4', 'B-4'])
>>> c.chordTablesAddress
ChordTableAddress(cardinality=3, forteClass=12, inversion=0, pcOriginal=2)

>>> c = chord.Chord('G#2 A2 D3 G3')
>>> c.chordTablesAddress
ChordTableAddress(cardinality=4, forteClass=6, inversion=0, pcOriginal=2)

This method caches the result so that it does not need to be looked up again.

One change from chord.tables.seekChordTablesAddress: the empty chord returns a special address instead of raising an exception:

>>> chord.Chord().chordTablesAddress
ChordTableAddress(cardinality=0, forteClass=0, inversion=0, pcOriginal=0)
Chord.commonName

Return the most common name associated with this Chord as a string. Checks some common enharmonic equivalents.

>>> c1 = chord.Chord(['c', 'e-', 'g'])
>>> c1.commonName
'minor triad'

>>> c2 = chord.Chord(['c', 'e', 'g'])
>>> c2.commonName
'major triad'

>>> c2b = chord.Chord(['c', 'f-', 'g'])
>>> c2b.commonName
'enharmonic equivalent to major triad'

>>> c3 = chord.Chord(['c', 'd-', 'e', 'f#'])
>>> c3.commonName
'all-interval tetrachord'

Chords with no common names just return the Forte Class

>>> c3 = chord.Chord([0, 1, 2, 3, 4, 9])
>>> c3.commonName
'forte class 6-36B'

Dominant seventh and German/Swiss sixths are distinguished

>>> c4a = chord.Chord(['c', 'e', 'g', 'b-'])
>>> c4a.commonName
'dominant seventh chord'

>>> c4b = chord.Chord(['c', 'e', 'g', 'a#'])
>>> c4b.commonName
'German augmented sixth chord'

>>> c4c = chord.Chord(['c', 'e', 'f##', 'a#'])
>>> c4c.commonName  # some call it Alsacian or English
'Swiss augmented sixth chord'

When in an unusual inversion, augmented sixth chords have their inversion added:

>>> c4b = chord.Chord('A#3 C4 E4 G4')
>>> c4b.commonName
'German augmented sixth chord in root position'

Dyads are called by actual name:

>>> dyad1 = chord.Chord('C E')
>>> dyad1.commonName
'Major Third'
>>> dyad2 = chord.Chord('C F-')
>>> dyad2.commonName
'Diminished Fourth'

Compound intervals are given in full if there are only two distinct pitches:

>>> dyad1 = chord.Chord('C4 E5')
>>> dyad1.commonName
'Major Tenth'

But if there are more pitches, then the interval is given in a simpler form:

>>> dyad1 = chord.Chord('C4 C5 E5 C6')
>>> dyad1.commonName
'Major Third with octave doublings'

If there are multiple enharmonics present just the simple number of semitones is returned.

>>> dyad1 = chord.Chord('C4 E5 F-5 B#7')
>>> dyad1.commonName
'4 semitones'

Special handling of one- and two-pitchClass chords:

>>> gAlone = chord.Chord(['G4'])
>>> gAlone.commonName
'note'
>>> gAlone = chord.Chord('G4 G4')
>>> gAlone.commonName
'unison'
>>> gAlone = chord.Chord('G4 G5')
>>> gAlone.commonName
'Perfect Octave'
>>> gAlone = chord.Chord('G4 G6')
>>> gAlone.commonName
'Perfect Double-octave'
>>> gAlone = chord.Chord('G4 G5 G6')
>>> gAlone.commonName
'multiple octaves'
>>> gAlone = chord.Chord('F#4 G-4')
>>> gAlone.commonName
'enharmonic unison'

>>> chord.Chord().commonName
'empty chord'

Microtonal chords all have the same commonName:

>>> chord.Chord('C`4 D~4').commonName
'microtonal chord'

Enharmonic equivalents to common sevenths and ninths are clarified:

>>> chord.Chord('C4 E4 G4 A##4').commonName
'enharmonic equivalent to major seventh chord'

>>> chord.Chord('C4 E-4 G4 A#4 D4').commonName
'enharmonic equivalent to minor-ninth chord'

Changed in v5.5: special cases for checking enharmonics in some cases Changed in v6.5: better handling of 0-, 1-, and 2-pitchClass and microtonal chords. Changed in v7: Inversions of augmented sixth-chords are specified. Changed in v7.3: Enharmonic equivalents to common seventh and ninth chords are specified.

Chord.fifth

Shortcut for getChordStep(5), but caches it and does not raise exceptions

>>> cMaj1stInv = chord.Chord(['E3', 'C4', 'G5'])
>>> cMaj1stInv.fifth
<music21.pitch.Pitch G5>

>>> cMaj1stInv.fifth.midi
79

>>> chord.Chord('C4 D4').fifth is None
True
Chord.forteClass

Return the Forte set class name as a string. This assumes a Tn formation, where inversion distinctions are represented.

(synonym: forteClassTn)

>>> c1 = chord.Chord(['c', 'e-', 'g'])
>>> c1.forteClass
'3-11A'

>>> c2 = chord.Chord(['c', 'e', 'g'])
>>> c2.forteClass
'3-11B'

Empty chords return ‘N/A’

>>> chord.Chord().forteClass
'N/A'

Non-twelve-tone chords return as if all microtones and non-twelve-tone accidentals are removed:

>>> chord.Chord('c~4 d`4').forteClass
'2-2'
Chord.forteClassNumber

Return the number of the Forte set class within the defined set group. That is, if the set is 3-11, this method returns 11.

>>> c1 = chord.Chord(['c', 'e-', 'g'])
>>> c1.forteClassNumber
11

>>> c2 = chord.Chord(['c', 'e', 'g'])
>>> c2.forteClassNumber
11
Chord.forteClassTn

A synonym for “forteClass”

Return the Forte Tn set class name, where inversion distinctions are represented:

>>> c1 = chord.Chord(['c', 'e-', 'g'])
>>> c1.forteClass
'3-11A'

>>> c2 = chord.Chord(['c', 'e', 'g'])
>>> c2.forteClassTn
'3-11B'
Chord.forteClassTnI

Return the Forte TnI class name, where inversion distinctions are not represented.

>>> c1 = chord.Chord(['c', 'e-', 'g'])
>>> c1.forteClassTnI
'3-11'

>>> c2 = chord.Chord(['c', 'e', 'g'])
>>> c2.forteClassTnI
'3-11'

Empty chords return ‘N/A’

>>> chord.Chord().forteClassTnI
'N/A'

Non-twelve-tone chords return as if all microtones and non-twelve-tone accidentals are removed:

>>> chord.Chord('c~4 d`4').forteClassTnI
'2-2'
Chord.fullName

Return the most complete representation of this Note, providing duration and pitch information.

>>> c = chord.Chord(['D', 'F#', 'A'])
>>> c.fullName
'Chord {D | F-sharp | A} Quarter'

>>> chord.Chord(['d1', 'e4-', 'b3-'], quarterLength=2/3).fullName
'Chord {D in octave 1 | E-flat in octave 4 | B-flat in octave 3} Quarter Triplet (2/3 QL)'
Chord.hasZRelation

Return True or False if the Chord has a Z-relation.

>>> c1 = chord.Chord(['c', 'e-', 'g'])
>>> c1.hasZRelation
False

>>> c2 = chord.Chord(['c', 'c#', 'e', 'f#'])
>>> c2.hasZRelation  # it is c, c#, e-, g
True
Chord.intervalVector

Return the interval vector for this Chord as a list of integers.

>>> c1 = chord.Chord(['c', 'e-', 'g'])
>>> c1.intervalVector
[0, 0, 1, 1, 1, 0]

>>> c2 = chord.Chord(['c', 'c#', 'e', 'f#'])
>>> c2.intervalVector
[1, 1, 1, 1, 1, 1]

>>> c3 = chord.Chord(['c', 'c#', 'e-', 'g'])
>>> c3.intervalVector
[1, 1, 1, 1, 1, 1]
Chord.intervalVectorString

Return the interval vector as a string representation.

>>> c1 = chord.Chord(['c', 'e-', 'g'])
>>> c1.intervalVectorString
'<001110>'
Chord.isPrimeFormInversion

Return True or False if the Chord represents a set class inversion.

>>> c1 = chord.Chord(['c', 'e-', 'g'])
>>> c1.isPrimeFormInversion
False

>>> c2 = chord.Chord(['c', 'e', 'g'])
>>> c2.isPrimeFormInversion
True
Chord.multisetCardinality

Return an integer representing the cardinality of the multiset, or the number of pitch values.

>>> c1 = chord.Chord(['D4', 'A4', 'F#5', 'D6'])
>>> c1.multisetCardinality
4
Chord.normalOrder

Return the normal order/normal form of the Chord represented as a list of integers:

>>> c1 = chord.Chord(['c', 'e-', 'g'])
>>> c1.normalOrder
[0, 3, 7]

>>> c2 = chord.Chord(['c', 'e', 'g'])
>>> c2.normalOrder
[0, 4, 7]

>>> c3 = chord.Chord(['d', 'f#', 'a'])
>>> c3.normalOrder
[2, 6, 9]

>>> c3 = chord.Chord(['B-4', 'D5', 'F5'])
>>> c3.normalOrder
[10, 2, 5]

To get normalOrder transposed to PC 0, do this:

>>> c3 = chord.Chord(['B-4', 'D5', 'F5'])
>>> normalOrder = c3.normalOrder
>>> firstPitch = normalOrder[0]
>>> [(pc - firstPitch) % 12 for pc in normalOrder]
[0, 4, 7]

To get normalOrder formatted as a vectorString run .formatVectorString on it:

>>> c3.normalOrder
[10, 2, 5]

>>> chord.Chord.formatVectorString(c3.normalOrder)
'<A25>'

(this is equivalent…)

>>> c3.formatVectorString(c3.normalOrder)
'<A25>'
Chord.normalOrderString

Return the normal order/normal form of the Chord as a string representation.

>>> c1 = chord.Chord(['c', 'e-', 'g'])
>>> c1.normalOrder
[0, 3, 7]

>>> c1.normalOrderString
'<037>'
Chord.orderedPitchClasses

Return a list of pitch class integers, ordered form lowest to highest.

>>> c1 = chord.Chord(['D4', 'A4', 'F#5', 'D6'])
>>> c1.orderedPitchClasses
[2, 6, 9]
Chord.orderedPitchClassesString

Return a string representation of the pitch class values.

>>> c1 = chord.Chord(['f#', 'e-', 'g'])
>>> c1.orderedPitchClassesString
'<367>'

Redundancies are removed

>>> c1 = chord.Chord(['f#', 'e-', 'e-', 'g'])
>>> c1.orderedPitchClassesString
'<367>'
Chord.pitchClassCardinality

Return the cardinality of pitch classes, or the number of unique pitch classes, in the Chord:

>>> c1 = chord.Chord(['D4', 'A4', 'F#5', 'D6'])
>>> c1.pitchClassCardinality
3
Chord.pitchClasses

Return a list of all pitch classes in the chord as integers. Not sorted

>>> c1 = chord.Chord(['D4', 'A4', 'F#5', 'D6'])
>>> c1.pitchClasses
[2, 9, 6, 2]
Chord.pitchedCommonName

Return a common name of this Chord including a pitch identifier, if possible:

Most common chords will use the root as the pitch name and have it at the beginning:

>>> c1 = chord.Chord(['c', 'e-', 'g'])
>>> c1.pitchedCommonName
'C-minor triad'

>>> c2 = chord.Chord(['c', 'e', 'g'])
>>> c2.pitchedCommonName
'C-major triad'

Because the hyphen is confusing w/ music21 flat notation, flats are displayed as “b”:

>>> c2a = chord.Chord('C-2 E-2 G-2')
>>> c2a.pitchedCommonName
'Cb-major triad'

Other forms might have the pitch elsewhere. Thus, this is a method for display, not for extracting information:

>>> c3 = chord.Chord('A#2 D3 F3')
>>> c3.pitchedCommonName
'enharmonic equivalent to major triad above A#'

Note that in this case, the bass, not the root is used to determine the pitch name:

>>> c4 = chord.Chord('D3 F3 A#3')
>>> c4.pitchedCommonName
'enharmonic equivalent to major triad above D'

>>> c5 = chord.Chord([1, 2, 3, 4, 5, 10])
>>> c5.pitchedCommonName
'forte class 6-36B above C#'

>>> c4 = chord.Chord('D3 F3 A#3')
>>> c4.pitchedCommonName
'enharmonic equivalent to major triad above D'

A single pitch just returns that pitch name:

>>> chord.Chord(['D3']).pitchedCommonName
'D'

Unless there is more than one octave:

>>> chord.Chord('D3 D4').pitchedCommonName
'Perfect Octave above D'
>>> chord.Chord('D3 D4 D5').pitchedCommonName
'multiple octaves above D'

Two different pitches give interval names:

>>> chord.Chord('F3 C4').pitchedCommonName
'Perfect Fifth above F'

Compound intervals are used unless there are multiple octaves:

>>> chord.Chord('E-3 C5').pitchedCommonName
'Major Thirteenth above Eb'
>>> chord.Chord('E-3 C5 C6').pitchedCommonName
'Major Sixth with octave doublings above Eb'

These one-pitch-class and two-pitch-class chords with multiple enharmonics are unusual:

>>> chord.Chord('D#3 E-3').pitchedCommonName
'enharmonic unison above D#'
>>> chord.Chord('D#3 E-3 D#4').pitchedCommonName
'enharmonic octaves above D#'
>>> chord.Chord('D#3 E-3 E3').pitchedCommonName
'1 semitone above D#'
>>> chord.Chord('D#3 E-3 F3 G--4').pitchedCommonName
'2 semitones above D#'

>>> chord.Chord().pitchedCommonName
'empty chord'

Changed in v5.5 – octaves never included, flats are converted, special tools for enharmonics. Changed in v6.5 – special names for 0-, 1-, and 2-pitchClass chords.

Chord.primeForm

Return a representation of the Chord as a prime-form list of pitch class integers:

>>> c1 = chord.Chord(['c', 'e-', 'g'])
>>> c1.primeForm
[0, 3, 7]

>>> c2 = chord.Chord(['c', 'e', 'g'])
>>> c2.primeForm
[0, 3, 7]
Chord.primeFormString

Return a representation of the Chord as a prime-form set class string.

>>> c1 = chord.Chord(['c', 'e-', 'g'])
>>> c1.primeFormString
'<037>'

>>> c1 = chord.Chord(['c', 'e', 'g'])
>>> c1.primeFormString
'<037>'
Chord.quality

Returns the quality of the underlying triad of a triad or seventh, either major, minor, diminished, augmented, or other:

>>> a = chord.Chord(['a', 'c', 'e'])
>>> a.quality
'minor'

Inversions don’t matter, nor do added tones so long as a root can be found:

>>> a = chord.Chord(['f', 'b', 'd', 'g'])
>>> a.quality
'major'

>>> a = chord.Chord(['c', 'a-', 'e'])
>>> a.quality
'augmented'

>>> a = chord.Chord(['c', 'c#', 'd'])
>>> a.quality
'other'

Incomplete triads are returned as major or minor:

>>> a = chord.Chord(['c', 'e-'])
>>> a.quality
'minor'

>>> a = chord.Chord(['e-', 'g'])
>>> a.quality
'major'

Chords that contain more than one triad return ‘other’

>>> chord.Chord('C C# E G').quality
'other'
>>> chord.Chord('C E- E G').quality
'other'
>>> chord.Chord('C E G- G').quality
'other'

Note these two edge cases:

>>> chord.Chord('C D E').quality  # NB! Major 9th....
'major'
>>> chord.Chord('C E--').quality
'other'

Empty chords are definitely ‘other’:

>>> chord.Chord().quality
'other'
Chord.scaleDegrees

Returns a list of two-element tuples for each pitch in the chord where the first element of the tuple is the scale degree as an int and the second is an Accidental object that specifies the alteration from the scale degree (could be None if the note is not part of the scale).

It is easiest to see the utility of this method using a chord subclass, music21.roman.RomanNumeral, but it is also callable from this Chord object if the Chord has a Key or Scale context set for it.

>>> k = key.Key('f#')  # 3-sharps minor
>>> rn = roman.RomanNumeral('V', k)
>>> rn.key
<music21.key.Key of f# minor>

>>> rn.pitches
(<music21.pitch.Pitch C#5>, <music21.pitch.Pitch E#5>, <music21.pitch.Pitch G#5>)

>>> rn.scaleDegrees
[(5, None), (7, <music21.pitch.Accidental sharp>), (2, None)]

>>> rn2 = roman.RomanNumeral('N6', k)
>>> rn2.pitches
(<music21.pitch.Pitch B4>, <music21.pitch.Pitch D5>, <music21.pitch.Pitch G5>)

>>> rn2.scaleDegrees  # N.B. -- natural form used for minor!
[(4, None), (6, None), (2, <music21.pitch.Accidental flat>)]

As mentioned above, the property can also get its scale from context if the chord is embedded in a Stream. Let’s create the same V in f#-minor again, but give it a context of c-sharp minor, and then c-minor instead:

>>> chord1 = chord.Chord(['C#5', 'E#5', 'G#5'])
>>> st1 = stream.Stream()
>>> st1.append(key.Key('c#'))  # c-sharp minor
>>> st1.append(chord1)
>>> chord1.scaleDegrees
[(1, None), (3, <music21.pitch.Accidental sharp>), (5, None)]

>>> st2 = stream.Stream()
>>> chord2 = chord.Chord(['C#5', 'E#5', 'G#5'])
>>> st2.append(key.Key('c'))  # c minor
>>> st2.append(chord2)        # same pitches as before gives different scaleDegrees
>>> chord2.scaleDegrees
[(1, <music21.pitch.Accidental sharp>),
 (3, <music21.pitch.Accidental double-sharp>),
 (5, <music21.pitch.Accidental sharp>)]

>>> st3 = stream.Stream()
>>> st3.append(key.Key('C'))  # C major
>>> chord2 = chord.Chord(['C4', 'C#4', 'D4', 'E-4', 'E4', 'F4'])  # 1st 1/2 of chromatic
>>> st3.append(chord2)
>>> chord2.scaleDegrees
[(1, None), (1, <music21.pitch.Accidental sharp>), (2, None),
 (3, <music21.pitch.Accidental flat>), (3, None), (4, None)]

Changed in v6.5 – will return None if no context can be found:

>>> chord.Chord('C4 E4 G4').scaleDegrees is None
True
Chord.seventh

Shortcut for getChordStep(7), but caches the value

>>> bDim7_2ndInv = chord.Chord(['F2', 'A-3', 'B4', 'D5'])
>>> bDim7_2ndInv.seventh
<music21.pitch.Pitch A-3>

Test whether this strange chord gets the B# not the C or something else:

>>> c = chord.Chord(['C4', 'E4', 'G4', 'B#4'])
>>> c.seventh
<music21.pitch.Pitch B#4>

Changed in v6.5 – return None on empty chords/errors

Chord.third

Shortcut for getChordStep(3), but caches the value, and returns None on errors.

>>> cMaj1stInv = chord.Chord(['E3', 'C4', 'G5'])
>>> cMaj1stInv.third
<music21.pitch.Pitch E3>

>>> cMaj1stInv.third.octave
3

Changed in v6.5 – return None on empty chords/errors

Read-only properties inherited from Music21Object:

Read-only properties inherited from ProtoM21Object:

Chord read/write properties

Chord.duration

Get or set the duration of this Chord as a Duration object.

>>> c = chord.Chord(['a', 'c', 'e'])
>>> c.duration
<music21.duration.Duration 1.0>

Durations can be overridden after the fact:

>>> d = duration.Duration()
>>> d.quarterLength = 2
>>> c.duration = d
>>> c.duration
<music21.duration.Duration 2.0>

>>> c.duration == d
True

>>> c.duration is d
True
Chord.notes

Return a tuple (immutable) of the notes contained in the chord.

Generally using .pitches or iterating over the chord is the best way to work with the components of a chord, but in unusual cases, a chord may, for instance, consist of notes with independent durations, volumes, or colors, or, more often, different tie statuses. Chord includes methods such as .setTie() for most of these features, but from time to time accessing all the Note objects as a tuple can be valuable.

>>> c1 = chord.Chord(['c', 'e-', 'g'])
>>> c1.duration.type = 'quarter'
>>> c1Notes = c1.notes
>>> c1Notes
(<music21.note.Note C>, <music21.note.Note E->, <music21.note.Note G>)

Note that to set duration independently, a new Duration object needs to be created. Internal notes for Chords created from strings or pitches all share a Duration object.

>>> c1.duration is c1Notes[0].duration
True
>>> c1Notes[1].duration is c1Notes[2].duration
True

>>> c1Notes[2].duration = duration.Duration('half')
>>> c1.duration.type
'quarter'
>>> c1[2].duration.type
'half'

The property can also set the notes for a chord, but it must be set to an iterable of literal Note objects.

>>> c1.notes = [note.Note('D#4'), note.Note('C#4')]
>>> c1
<music21.chord.Chord D#4 C#4>

Notice that the notes set this way are not sorted – this is a property for power users who want complete control.

Any incorrect assignment raises a TypeError:

>>> c1.notes = 'C E G'
Traceback (most recent call last):
TypeError: notes must be set with an iterable

>>> c1.notes = [pitch.Pitch('C'), pitch.Pitch('E')]
Traceback (most recent call last):
TypeError: every element of notes must be a note.Note object

In case of an error, the previous notes are not changed (for this reason, .notes cannot take a generator expression).

>>> c1
<music21.chord.Chord D#4 C#4>

new in v5.7

Chord.pitchNames

Return a list of Pitch names from each Pitch object’s name attribute.

>>> c = chord.Chord(['g#', 'd-'])
>>> c.pitchNames
['G#', 'D-']

>>> c = chord.Chord('C4 E4 G4 C4')
>>> c.pitchNames
['C', 'E', 'G', 'C']

>>> c.pitchNames = ['c2', 'g2']
>>> c.pitchNames
['C', 'G']
Chord.pitches

Get or set a list or tuple of all Pitch objects in this Chord.

>>> c = chord.Chord(['C4', 'E4', 'G#4'])
>>> c.pitches
(<music21.pitch.Pitch C4>, <music21.pitch.Pitch E4>, <music21.pitch.Pitch G#4>)

>>> [p.midi for p in c.pitches]
[60, 64, 68]

>>> d = chord.Chord()
>>> d.pitches = c.pitches
>>> d.pitches
(<music21.pitch.Pitch C4>, <music21.pitch.Pitch E4>, <music21.pitch.Pitch G#4>)

>>> c = chord.Chord(['C4', 'A4', 'E5'])
>>> c.bass()
<music21.pitch.Pitch C4>

>>> c.root()
<music21.pitch.Pitch A4>

Note here that the list will be converted to a tuple:

>>> c.pitches = ['C#4', 'A#4', 'E#5']
>>> c.pitches
(<music21.pitch.Pitch C#4>, <music21.pitch.Pitch A#4>, <music21.pitch.Pitch E#5>)

Bass and root information is also changed.

>>> c.bass()
<music21.pitch.Pitch C#4>

>>> c.root()
<music21.pitch.Pitch A#4>

Read/write properties inherited from ChordBase:

Read/write properties inherited from NotRest:

Read/write properties inherited from GeneralNote:

Read/write properties inherited from Music21Object:

Chord methods

Chord.__eq__(other)

True if the Chord passes all super() equality tests and the pitches are the same (possibly in a different order)

>>> c1 = chord.Chord('C4 E4 G4')
>>> c2 = chord.Chord('E4 C4 G4')
>>> c1 == c2
True
>>> c3 = chord.Chord('E4 C#4 G4')
>>> c2 == c3
False
>>> n1 = note.Note('C4')
>>> c1 == n1
False
>>> c2.duration.quarterLength = 2.0
>>> c1 == c2
False
>>> c1 != c2
True
Chord.__getitem__(key: int | str | Note | Pitch)

Get item makes accessing pitch components for the Chord easier

>>> c = chord.Chord('C#4 D-4')
>>> cSharp = c[0]
>>> cSharp
<music21.note.Note C#>

>>> c['0.step']
'C'
>>> c['3.accidental']
Traceback (most recent call last):
KeyError: "Cannot access component with: '3.accidental'"

>>> c[5]
Traceback (most recent call last):
KeyError: 'Cannot access component with: 5'

>>> c['D-4']
<music21.note.Note D->

>>> c['D-4.style.color'] is None
True

Getting by note does not do very much…

>>> c[cSharp]
<music21.note.Note C#>

But we can get from another note

>>> cSharp2 = note.Note('C#4')
>>> cSharp2.duration.quarterLength = 3.0
>>> c[cSharp2] is cSharp
True
>>> c[cSharp2] is cSharp2
False

KeyError is raised if not in chord.

>>> notInChord = note.Note('G')
>>> c[notInChord]
Traceback (most recent call last):
KeyError: 'Cannot access component with: <music21.note.Note G>'

>>> c[None]
Traceback (most recent call last):
KeyError: 'Cannot access component with: None'
Chord.add(notes, *, runSort=True) → None

Add a Note, Pitch, the .notes of another chord, or string representing a pitch, or a list of any-of-the-above types to a Chord.

If runSort is True (default=True) then after appending, the chord will be sorted.

>>> c = chord.Chord('C4 E4 G4')
>>> c.add('B3')
>>> c
<music21.chord.Chord B3 C4 E4 G4>
>>> c.duration
<music21.duration.Duration 1.0>

>>> c.add('A2', runSort=False)
>>> c
<music21.chord.Chord B3 C4 E4 G4 A2>

>>> c.add(['B5', 'C6'])
>>> c
<music21.chord.Chord A2 B3 C4 E4 G4 B5 C6>

>>> c.add(pitch.Pitch('D6'))
>>> c
<music21.chord.Chord A2 B3 C4 E4 G4 B5 C6 D6>

>>> n = note.Note('E6')
>>> n.duration.type = 'half'
>>> c.add(n)
>>> c
<music21.chord.Chord A2 B3 C4 E4 G4 B5 C6 D6 E6>
>>> c.duration
<music21.duration.Duration 1.0>
>>> c[-1]
<music21.note.Note E>
>>> c[-1].duration
<music21.duration.Duration 2.0>

Overrides ChordBase.add() to permit sorting with runSort.

Chord.annotateIntervals(*, inPlace=True, stripSpecifiers=True, sortPitches=True, returnList=False)

Add lyrics to the chord that show the distance of each note from the bass. If returnList is True, a list of the intervals is returned instead.

By default, we show only the generic interval:

>>> c1 = chord.Chord(['C2', 'E2', 'G2', 'C3'])
>>> c2 = c1.annotateIntervals(inPlace=False)
>>> c2.lyrics
[<music21.note.Lyric number=1 syllabic=single text='8'>,
 <music21.note.Lyric number=2 syllabic=single text='5'>,
 <music21.note.Lyric number=3 syllabic=single text='3'>]

>>> [ly.text for ly in c2.lyrics]
['8', '5', '3']

The stripSpecifiers parameter can be used to show only the intervals size (3, 5, etc.) or the complete interval specification (m3, P5, etc.)

>>> c3 = c1.annotateIntervals(inPlace=False, stripSpecifiers=False)
>>> c3.lyrics
[<music21.note.Lyric number=1 syllabic=single text='P8'>,
 <music21.note.Lyric number=2 syllabic=single text='P5'>,
 <music21.note.Lyric number=3 syllabic=single text='M3'>]

>>> [ly.text for ly in c3.lyrics]
['P8', 'P5', 'M3']

This chord was giving us problems:

>>> c4 = chord.Chord(['G4', 'E4', 'B3', 'E3'])
>>> c4.annotateIntervals(stripSpecifiers=False)
>>> [ly.text for ly in c4.lyrics]
['m3', 'P8', 'P5']
>>> c4.annotateIntervals(inPlace=True, stripSpecifiers=False, returnList=True)
['m3', 'P8', 'P5']

If sortPitches is false it still gives problems…

>>> c4 = chord.Chord(['G4', 'E4', 'B3', 'E3'])
>>> c4.annotateIntervals(inPlace=True, stripSpecifiers=False, sortPitches=False)
>>> [ly.text for ly in c4.lyrics]
['m3', 'm6', 'm3']

>>> c = chord.Chord(['c4', 'd-4', 'g4'])
>>> c.annotateIntervals(inPlace=True)
>>> [ly.text for ly in c.lyrics]
['5', '2']

>>> c = chord.Chord(['c4', 'd-4', 'g4'])
>>> c.annotateIntervals(inPlace=True, stripSpecifiers=False)
>>> [ly.text for ly in c.lyrics]
['P5', 'm2']

>>> c = chord.Chord(['c4', 'd---4', 'g4'])
>>> c.annotateIntervals(inPlace=True, stripSpecifiers=False)
>>> [ly.text for ly in c.lyrics]
['P5', 'dd2']

>>> c = chord.Chord(['c4', 'g5', 'e6'])
>>> c.annotateIntervals(inPlace=True)
>>> [ly.text for ly in c.lyrics]
['5', '3']
Chord.areZRelations(other: _ChordType) → bool

Check if another Chord is a z-relation to this Chord.

>>> c1 = chord.Chord(['C', 'c#', 'e', 'f#'])
>>> c2 = chord.Chord(['C', 'c#', 'e-', 'g'])
>>> c3 = chord.Chord(['C', 'c#', 'f#', 'g'])
>>> c1.areZRelations(c2)
True

>>> c1.areZRelations(c3)
False

If there is no z-relation for the first chord, obviously return False:

>>> c4 = chord.Chord('C E G')
>>> c4.areZRelations(c3)
False
Chord.bass(newbass: None = None, *, find: bool | None = None, allow_add: bool = False) → Pitch
Chord.bass(newbass: str | Pitch | Note, *, find: bool | None = None, allow_add: bool = False) → None

Generally used to find and return the bass Pitch:

>>> cmaj1stInv = chord.Chord(['C4', 'E3', 'G5'])
>>> cmaj1stInv.bass()
<music21.pitch.Pitch E3>

Subclasses of Chord often have basses that are harder to determine.

>>> cmaj = harmony.ChordSymbol('CM')
>>> cmaj.bass()
<music21.pitch.Pitch C3>

>>> cmin_inv = harmony.ChordSymbol('Cm/E-')
>>> cmin_inv.bass()
<music21.pitch.Pitch E-3>

Can also be used in rare occasions to set the bass note to a new Pitch, so long as that note is found in the chord:

>>> strange_chord = chord.Chord('E##4 F-4 C5')
>>> strange_chord.bass()
<music21.pitch.Pitch E##4>
>>> strange_chord.bass('F-4')
>>> strange_chord.bass()
<music21.pitch.Pitch F-4>

If the note assigned to the bass is not found, it will default to raising a ChordException:

>>> strange_chord.bass('G--4')
Traceback (most recent call last):
music21.chord.ChordException: Pitch G--4 not found in chord

For the purposes of initializing from a ChordSymbol and in other cases, a new bass can be added to the chord by setting allow_add = True:

>>> strange_chord.bass('G--4', allow_add=True)
>>> strange_chord.bass()
<music21.pitch.Pitch G--4>

By default, if nothing has been overridden, this method uses a quick algorithm to find the bass among the chord’s pitches, if no bass has been previously specified. If this is not intended, set find to False when calling this method, and ‘None’ will be returned if no bass is specified

>>> em = chord.Chord(['E3', 'G3', 'B4'])
>>> print(em.bass(find=False))
None

Changed in v8: raise an exception if setting a new bass to a pitch not in the chord, unless new keyword allow_add is True.

Chord.canBeDominantV() → bool

Returns True if the chord is a Major Triad or a Dominant Seventh:

>>> gSeven = chord.Chord(['g', 'b', 'd', 'f'])
>>> gSeven.canBeDominantV()
True

>>> gDim = chord.Chord(['g', 'b-', 'd-'])
>>> gDim.canBeDominantV()
False
Chord.canBeTonic() → bool

Returns True if the chord is a major or minor triad:

>>> a = chord.Chord(['g', 'b', 'd', 'f'])
>>> a.canBeTonic()
False

>>> a = chord.Chord(['g', 'b', 'd'])
>>> a.canBeTonic()
True
Chord.closedPosition(*, forceOctave: int | None, inPlace: Literal[True], leaveRedundantPitches=False) → None
Chord.closedPosition(*, forceOctave: int | None = None, inPlace: Literal[False] = False, leaveRedundantPitches: bool = False) → _ChordType

Returns a new Chord object with the same pitch classes, but now in closed position.

If forcedOctave is provided, the bass of the chord will be shifted to that provided octave.

If inPlace is True then the original chord is returned with new pitches.

>>> chord1 = chord.Chord(['C#4', 'G5', 'E6'])
>>> chord2 = chord1.closedPosition()
>>> chord2
<music21.chord.Chord C#4 E4 G4>

Force octave changes the octave of the bass note (and all notes above it…)

>>> c2 = chord.Chord(['C#4', 'G5', 'E6'])
>>> c2.closedPosition(forceOctave=2)
<music21.chord.Chord C#2 E2 G2>

>>> c3 = chord.Chord(['C#4', 'G5', 'E6'])
>>> c3.closedPosition(forceOctave=6)
<music21.chord.Chord C#6 E6 G6>

Redundant pitches are removed by default, but can be retained…

>>> c4 = chord.Chord(['C#4', 'C5', 'F7', 'F8'])
>>> c5 = c4.closedPosition(forceOctave=4, inPlace=False)
>>> c5
<music21.chord.Chord C#4 F4 C5>

>>> c6 = c4.closedPosition(forceOctave=4, inPlace=False, leaveRedundantPitches=True)
>>> c6
<music21.chord.Chord C#4 F4 F4 C5>

Implicit octaves work fine…

>>> c7 = chord.Chord(['A4', 'B4', 'A'])
>>> c7.closedPosition(forceOctave=4, inPlace=True)
>>> c7
<music21.chord.Chord A4 B4>
Chord.containsSeventh() → bool

Returns True if the chord contains at least one of each of Third, Fifth, and Seventh. raises an exception if the Root can’t be determined

A ninth chord contains a seventh:

>>> c9 = chord.Chord(['C4', 'E4', 'G4', 'B4', 'D5'])
>>> c9.containsSeventh()
True

As does a cluster:

>>> cluster = chord.Chord('C D E F G A B')
>>> cluster.containsSeventh()
True

But a major triad does not:

>>> dMaj = chord.Chord([pitch.Pitch('D4'), pitch.Pitch('F#4'), pitch.Pitch('A5')])
>>> dMaj.containsSeventh()
False

Note that a seventh chord itself contains a seventh.

>>> cChord = chord.Chord(['C', 'E', 'G', 'B'])
>>> cChord.containsSeventh()
True

Empty chord returns False

>>> chord.Chord().containsSeventh()
False
Chord.containsTriad() → bool

Returns True or False if there is no triad above the root. “Contains vs. Is”: A dominant-seventh chord contains a triad.

>>> cChord = chord.Chord(['C', 'E', 'G'])
>>> other = chord.Chord(['C', 'D', 'E', 'F', 'G'])
>>> cChord.containsTriad()
True

>>> other.containsTriad()
True

>>> scale = chord.Chord(['C', 'D-', 'E', 'F#', 'G', 'A#', 'B'])
>>> scale.containsTriad()
True

>>> c = chord.Chord('C4 D4')
>>> c.containsTriad()
False

>>> chord.Chord().containsTriad()
False
static Chord.formatVectorString(vectorList) → str

Return a string representation of a vector or set

Static method. Works on the class:

>>> chord.Chord.formatVectorString([0, 11])
'<0B>'

or an existing chord:

>>> c1 = chord.Chord(['D4', 'A4', 'F#5', 'D6'])
>>> c1.formatVectorString(c1.normalOrder)
'<269>'

or on a list that has nothing to do with the chord

>>> c1.formatVectorString([10, 11, 3, 5])
'<AB35>'
Chord.geometricNormalForm() → List[int]

Geometric Normal Form, as first defined by Dmitri Tymoczko, orders pitch classes such that the spacing is prioritized with the smallest spacing between the first and second pitch class first, then the smallest spacing between second and third pitch class, and so on. This form has unique properties that make it useful. It also transposes to PC0

geometricNormalForm returns a list of pitch class integers in geometric normal form.

Example 1: A major triad has geometricNormalForm of 038 not 047.

>>> c1 = chord.Chord('E4 C5 G6 C7')
>>> pcList = c1.geometricNormalForm()
>>> pcList
[0, 3, 8]

>>> c2 = chord.Chord(pcList)
>>> c2.orderedPitchClassesString
'<038>'

Compare this to the usual normalOrder transposed to PC0:

>>> normalOrder = c1.normalOrder
>>> normalOrderFirst = normalOrder[0]
>>> [(pc - normalOrderFirst) % 12 for pc in normalOrder]
[0, 4, 7]
Chord.getChordStep(chordStep: int, *, testRoot: Note | Pitch | None = None) → Pitch | None

Returns the (first) pitch at the provided scaleDegree (Thus, it’s exactly like semitonesFromChordStep, except it instead of the number of semitones.)

Returns None if none can be found.

>>> cmaj = chord.Chord(['C', 'E', 'G'])
>>> cmaj.getChordStep(3)  # will return the third of the chord
<music21.pitch.Pitch E>

>>> g = cmaj.getChordStep(5)  # will return the fifth of the chord
>>> g.name
'G'

>>> cmaj.getChordStep(6) is None
True

Ninths can be specified with either 9 or 2. Similarly for elevenths and thirteenths.

>>> c9 = chord.Chord('C4 E4 G4 B4 D5')
>>> c9.getChordStep(9)
<music21.pitch.Pitch D5>
>>> c9.getChordStep(2)
<music21.pitch.Pitch D5>

  • Changed in v8.3 –

Chord.getColor(pitchTarget)

For a pitch in this Chord, return the color stored in self.editorial, or, if set for each component, return the color assigned to this component.

First checks for “is” then “equals”

>>> p = pitch.Pitch('C4')
>>> n = note.Note(p)
>>> n.style.color = 'red'
>>> c = chord.Chord([n, 'E4'])
>>> c.getColor(p)
'red'
>>> c.getColor('C4')
'red'
>>> c.getColor('E4') is None
True

The color of any pitch (even a non-existing one) is the color of the chord if the color of that pitch is not defined.

>>> c.style.color = 'pink'
>>> c.getColor('E4')
'pink'
>>> c.getColor('D#7')
'pink'
Chord.getNotehead(p)

Given a pitch in this Chord, return an associated notehead attribute, or return ‘normal’ if not defined for that Pitch.

If the pitch is not found, None will be returned.

>>> n1 = note.Note('D4')
>>> n2 = note.Note('G4')
>>> n2.notehead = 'diamond'
>>> c1 = chord.Chord([n1, n2])
>>> c1.getNotehead(c1.pitches[1])
'diamond'

>>> c1.getNotehead(c1.pitches[0])
'normal'

>>> c1.getNotehead(pitch.Pitch('A#6')) is None
True

Will work if the two notes are equal in pitch

>>> c1.getNotehead(note.Note('G4'))
'diamond'
Chord.getNoteheadFill(p)

Given a pitch in this Chord, return an associated noteheadFill attribute, or return None if not defined for that Pitch.

If the pitch is not found, None will also be returned.

>>> n1 = note.Note('D4')
>>> n2 = note.Note('G4')
>>> n2.noteheadFill = True
>>> c1 = chord.Chord([n1, n2])
>>> c1.getNoteheadFill(c1.pitches[1])
True

>>> print(c1.getNoteheadFill(c1.pitches[0]))
None

>>> c1.getNoteheadFill(pitch.Pitch('A#6')) is None
True

Will work if the two notes are equal in pitch

>>> c1.getNoteheadFill(note.Note('G4'))
True

Returns None if the pitch is not in the Chord:

Chord.getStemDirection(p)

Given a pitch in this Chord, return an associated stem attribute, or return ‘unspecified’ if not defined for that Pitch or None.

If the pitch is not found, None will be returned.

>>> n1 = note.Note('D4')
>>> n2 = note.Note('G4')
>>> n2.stemDirection = 'double'
>>> c1 = chord.Chord([n1, n2])
>>> c1.getStemDirection(c1.pitches[1])
'double'

>>> c1.getStemDirection(c1.pitches[0])
'unspecified'

Will work if the two pitches are equal in pitch

>>> c1.getStemDirection(note.Note('G4'))
'double'

Returns None if a Note or Pitch is not in the Chord

>>> c1.getStemDirection(pitch.Pitch('A#4')) is None
True
Chord.getTie(p)

Given a pitch in this Chord, return an associated Tie object, or return None if not defined for that Pitch.

>>> c1 = chord.Chord(['d', 'e-', 'b-'])
>>> t1 = tie.Tie('start')
>>> c1.setTie(t1, c1.pitches[2])  # just to b-
>>> c1.getTie(c1.pitches[2]) == t1
True

>>> c1.getTie(c1.pitches[0]) is None
True

All notes not in chord return None

>>> c1.getTie(pitch.Pitch('F#2')) is None
True

>>> c1.getTie('B-')
<music21.tie.Tie start>
Chord.getVolume(p)

For a given Pitch in this Chord, return the Volume object.

Raises an exception if the pitch isn’t in the chord (TODO: consider changing to be like notehead, etc.)

>>> c = chord.Chord('C4 F4')
>>> c[0].volume = 2
>>> c.getVolume('C4')
<music21.volume.Volume realized=0.02>

>>> c.getVolume('F4')  # default
<music21.volume.Volume realized=0.71>

>>> c.getVolume('G4')
Traceback (most recent call last):
music21.chord.ChordException: the given pitch is not in the Chord: G4
Chord.getZRelation() → Chord | None

Return a Z relation if it exists, otherwise return None.

>>> chord.fromIntervalVector((1, 1, 1, 1, 1, 1))
<music21.chord.Chord C C# E F#>

>>> chord.fromIntervalVector((1, 1, 1, 1, 1, 1)).getZRelation()
<music21.chord.Chord C D- E- G>

Z relation will always be zero indexed:

>>> c = chord.Chord('D D# F# G#')
>>> c.getZRelation()
<music21.chord.Chord C D- E- G>

>>> chord.Chord('C E G').getZRelation() is None
True
Chord.hasAnyEnharmonicSpelledPitches() → bool

Returns True if for any given pitchClass there is at most one spelling of the note (in any octave).

>>> cChord = chord.Chord('C4 E4 G4 C5')
>>> cChord.hasAnyEnharmonicSpelledPitches()
False

Notice that having a C in two different octaves is no problem. However, this is False:

>>> cChord = chord.Chord('C4 E4 G4 B#4')
>>> cChord.hasAnyEnharmonicSpelledPitches()
True
Chord.hasAnyRepeatedDiatonicNote() → bool

Returns True if for any diatonic note (e.g., C or C# = C) there are two or more different notes (such as E and E-) in the chord. If there are no repeated scale degrees, return False.

>>> cChord = chord.Chord(['C', 'E', 'E-', 'G'])
>>> cChord.hasAnyRepeatedDiatonicNote()
True

This routine is helpful for anything that works with Generic intervals and chord steps such as .third which makes sure that checking for root, second, third, …, seventh will actually find all the different notes.

This following example returns False because chromatically identical notes of different scale degrees do not count as a repeated diatonic note. (See hasAnyEnharmonicSpelledPitches() for that method)

>>> other = chord.Chord(['C', 'E', 'F-', 'G'])
>>> other.hasAnyRepeatedDiatonicNote()
False
Chord.hasRepeatedChordStep(chordStep, *, testRoot=None)

Returns True if chordStep above testRoot (or self.root()) has two or more different notes (such as E and E-) in it. Otherwise returns False.

>>> cChord = chord.Chord(['G2', 'E4', 'E-5', 'C6'])
>>> cChord.hasRepeatedChordStep(3)
True

>>> cChord.hasRepeatedChordStep(5)
False
Chord.intervalFromChordStep(chordStep, *, testRoot=None)

Exactly like semitonesFromChordStep, except it returns the interval itself instead of the number of semitones:

>>> cmaj = chord.Chord(['C', 'E', 'G'])
>>> cmaj.intervalFromChordStep(3)  # will return the interval between C and E
<music21.interval.Interval M3>

>>> cmaj.intervalFromChordStep(5)  # will return the interval between C and G
<music21.interval.Interval P5>

>>> print(cmaj.intervalFromChordStep(6))
None
Chord.inversion(newInversion: int, *, find: bool = True, testRoot: Pitch | None = None, transposeOnSet: bool = True) → None
Chord.inversion(newInversion: None = None, *, find: bool = True, testRoot: Pitch | None = None, transposeOnSet: bool = True) → int

Find the chord’s inversion or (if called with a number) set the chord to the new inversion.

When called without a number argument, returns an integer (or None) representing which inversion (if any) the chord is in. The Chord does not have to be complete, in which case this function determines the inversion by looking at the relationship of the bass note to the root.

Returns a maximum value of 5 for the fifth inversion of a thirteenth chord. Returns 0 if the bass to root interval is a unison or if interval is not a common inversion (1st-5th). The octave of the bass and root are irrelevant to this calculation of inversion. Returns None if the Chord has no pitches.

>>> g7 = chord.Chord(['g4', 'b4', 'd5', 'f5'])
>>> g7.inversion()
0
>>> g7.inversion(1)
>>> g7
<music21.chord.Chord B4 D5 F5 G5>

With implicit octaves, D becomes the bass (since octaves start on C):

>>> g7_implicit = chord.Chord(['g', 'b', 'd', 'f'])
>>> g7_implicit.inversion()
2

Note that in inverting a chord with implicit octaves, some pitches will gain octave designations, but not necessarily all of them (this behavior might change in the future):

>>> g7_implicit.inversion(1)
>>> g7_implicit
<music21.chord.Chord B D5 F5 G5>

Examples of each inversion:

>>> cTriad1stInversion = chord.Chord(['E1', 'G1', 'C2'])
>>> cTriad1stInversion.inversion()
1

>>> cTriad2ndInversion = chord.Chord(['G1', 'E2', 'C2'])
>>> cTriad2ndInversion.inversion()
2

>>> dSeventh3rdInversion = chord.Chord(['C4', 'B4'])
>>> dSeventh3rdInversion.bass(pitch.Pitch('B4'))
>>> dSeventh3rdInversion.inversion()
3

>>> gNinth4thInversion = chord.Chord(['G4', 'B4', 'D5', 'F5', 'A4'])
>>> gNinth4thInversion.bass(pitch.Pitch('A4'))
>>> gNinth4thInversion.inversion()
4

>>> bbEleventh5thInversion = chord.Chord(['B-', 'D', 'F', 'A', 'C', 'E-'])
>>> bbEleventh5thInversion.bass(pitch.Pitch('E-4'))
>>> bbEleventh5thInversion.inversion()
5

Repeated notes do not affect the inversion:

>>> gMajRepeats = chord.Chord(['G4', 'B5', 'G6', 'B6', 'D7'])
>>> gMajRepeats.inversion(2)
>>> gMajRepeats
<music21.chord.Chord D7 G7 B7 G8 B8>

>>> gMajRepeats.inversion(3)
Traceback (most recent call last):
music21.chord.ChordException: Could not invert chord...inversion may not exist

If testRoot is True then that temporary root is used instead of self.root().

Get the inversion for a seventh chord showing different roots

>>> dim7 = chord.Chord('B4 D5 F5 A-5 C6 E6 G6')
>>> dim7.inversion()
0
>>> dim7.inversion(testRoot=pitch.Pitch('D5'))
6
>>> dim7.inversion('six-four')
Traceback (most recent call last):
music21.chord.ChordException: Inversion must be an integer, got: <class 'str'>

Chords without pitches or otherwise impossible chords return -1, indicating no normal inversion.

>>> chord.Chord().inversion(testRoot=pitch.Pitch('C5'))
-1

For Harmony subclasses, this method does not check to see if the inversion is reasonable according to the figure provided. see inversionIsValid() for checker method on ChordSymbolObjects.

If only two pitches given, an inversion is still returned, often as if it were a triad:

>>> chord.Chord('C4 G4').inversion()
0
>>> chord.Chord('G4 C5').inversion()
2

If transposeOnSet is False then setting the inversion simply sets the value to be returned later, which might be useful for cases where the chords are poorly spelled, or there is an added note.

Changed in v.8 – chords without pitches

Chord.inversionName()

Returns an integer representing the common abbreviation for the inversion the chord is in. If chord is not in a common inversion, returns None.

Third inversion sevenths return 42 not 2.

>>> a = chord.Chord(['G3', 'B3', 'F3', 'D3'])
>>> a.inversionName()
43
Chord.inversionText() → str

A helper method to return a readable inversion text (with capitalization) for a chord:

>>> chord.Chord('C4 E4 G4').inversionText()
'Root Position'
>>> chord.Chord('E4 G4 C5').inversionText()
'First Inversion'

>>> chord.Chord('B-3 C4 E4 G4').inversionText()
'Third Inversion'

>>> chord.Chord().inversionText()
'Unknown Position'
Chord.isAugmentedSixth(*, permitAnyInversion=False)

returns True if the chord is an Augmented 6th chord in normal inversion. (that is, in first inversion for Italian and German and second for French and Swiss)

>>> c = chord.Chord(['A-3', 'C4', 'E-4', 'F#4'])
>>> c.isAugmentedSixth()
True

Spelling matters

>>> c.pitches[3].getEnharmonic(inPlace=True)
>>> c
<music21.chord.Chord A-3 C4 E-4 G-4>
>>> c.isAugmentedSixth()
False

Italian…

>>> c = chord.Chord(['A-3', 'C4', 'F#4'])
>>> c.isAugmentedSixth()
True

If permitAnyInversion is True then any inversion is allowed.

Chord.isAugmentedTriad()

Returns True if chord is an Augmented Triad, that is, if it contains only notes that are either in unison with the root, a major third above the root, or an augmented fifth above the root. Additionally, the Chord must contain at least one of each third and fifth above the root.

The chord might not seem to need to be spelled correctly since incorrectly spelled Augmented Triads are usually augmented triads in some other inversion (e.g. C-E-Ab is a second-inversion augmented triad; C-Fb-Ab is in first inversion). However, B#-Fb-Ab does return False as it is not a stack of two major thirds in any inversion.

Returns False if is not an augmented triad.

>>> c = chord.Chord(['C4', 'E4', 'G#4'])
>>> c.isAugmentedTriad()
True
>>> c = chord.Chord(['C4', 'E4', 'G4'])
>>> c.isAugmentedTriad()
False

Other spellings will give other roots!

>>> c = chord.Chord(['C4', 'E4', 'A-4'])
>>> c.isAugmentedTriad()
True
>>> c.root()
<music21.pitch.Pitch A-4>

>>> c = chord.Chord(['C4', 'F-4', 'A-4'])
>>> c.isAugmentedTriad()
True
>>> c = chord.Chord(['B#4', 'F-4', 'A-4'])
>>> c.isAugmentedTriad()
False

>>> chord.Chord().isAugmentedTriad()
False
Chord.isConsonant()
returns True if the chord is

one pitch two pitches: uses isConsonant() , which checks if interval is a major or minor third or sixth or perfect fifth. three pitches: if chord is a major or minor triad not in second inversion.

These rules define all common-practice consonances (and earlier back to about 1300 all imperfect consonances)

>>> c1 = chord.Chord(['C3', 'E4', 'G5'])
>>> c1.isConsonant()
True

>>> c2 = chord.Chord(['G3', 'E-4', 'C5'])
>>> c2.isConsonant()
False

>>> c3 = chord.Chord(['F2', 'A2', 'C3', 'E-3'])
>>> c3.isConsonant()
False

>>> c4 = chord.Chord(['C1', 'G1', 'C2', 'G2', 'C3', 'G3'])
>>> c4.isConsonant()
True

>>> c5 = chord.Chord(['G1', 'C2', 'G2', 'C3', 'G3'])
>>> c5.isConsonant()
False

>>> c6 = chord.Chord(['F#'])
>>> c6.isConsonant()
True

>>> c7 = chord.Chord(['C1', 'C#1', 'D-1'])
>>> c7.isConsonant()
False

Spelling does matter:

>>> c8 = chord.Chord(['D-4', 'G#4'])
>>> c8.isConsonant()
False

>>> c9 = chord.Chord(['D3', 'A2', 'D2', 'D2', 'A4'])
>>> c9.isConsonant()
True

>>> c10 = chord.Chord(['D3', 'A2', 'D2', 'D2', 'A1'])
>>> c10.isConsonant()
False

>>> c11 = chord.Chord(['F3', 'D4', 'A4'])
>>> c11.isConsonant()
True

>>> c12 = chord.Chord(['F3', 'D4', 'A4', 'E#4'])
>>> c12.isConsonant()
False
Chord.isDiminishedSeventh()

Returns True if chord is a Diminished Seventh, that is, if it contains only notes that are either in unison with the root, a minor third above the root, a diminished fifth, or a minor seventh above the root. Additionally, must contain at least one of each third and fifth above the root. Chord must be spelled correctly. Otherwise returns false.

>>> a = chord.Chord(['c', 'e-', 'g-', 'b--'])
>>> a.isDiminishedSeventh()
True

>>> chord.Chord().isDiminishedSeventh()
False
Chord.isDiminishedTriad() → bool

Returns True if chord is a Diminished Triad, that is, if it contains only notes that are either in unison with the root, a minor third above the root, or a diminished fifth above the root. Additionally, must contain at least one of each third and fifth above the root. Chord must be spelled correctly. Otherwise returns false.

>>> cChord = chord.Chord(['C', 'E-', 'G-'])
>>> cChord.isDiminishedTriad()
True
>>> other = chord.Chord(['C', 'E-', 'F#'])
>>> other.isDiminishedTriad()
False
Chord.isDominantSeventh() → bool

Returns True if chord is a Dominant Seventh, that is, if it contains only notes that are either in unison with the root, a major third above the root, a perfect fifth, or a major seventh above the root. Additionally, must contain at least one of each third and fifth above the root. Chord must be spelled correctly. Otherwise returns false.

>>> a = chord.Chord(['b', 'g', 'd', 'f'])
>>> a.isDominantSeventh()
True

>>> chord.Chord().isDominantSeventh()
False

>>> c2 = chord.Chord('C4 E4 G4 A#4')
>>> c2.isDominantSeventh()
False
Chord.isFalseDiminishedSeventh() → bool

Returns True if chord is a Diminished Seventh, that is, if it contains only notes that are either in unison with the root, a minor third above the root, a diminished fifth, or a diminished seventh above the root. Additionally, must contain at least one of each third and fifth above the root. Chord MAY BE SPELLED INCORRECTLY. Otherwise returns False.

>>> c = chord.Chord('C D# G- A')
>>> c.isFalseDiminishedSeventh()
True

>>> chord.Chord().isFalseDiminishedSeventh()
False

>>> chord.Chord('C4 E4 G4').isFalseDiminishedSeventh()
False

Correctly spelled diminished seventh chords are also false diminished sevenths.

>>> chord.Chord('C4 E-4 G-4 B--4').isFalseDiminishedSeventh()
True
Chord.isFrenchAugmentedSixth(*, permitAnyInversion=False) → bool

Returns True if the chord is a French augmented sixth chord (flat 6th scale degree in bass, tonic, second scale degree, and raised 4th).

N.B. The root() method of music21.chord.Chord determines the root based on the note with the most thirds above it. However, under this definition, a 1st-inversion french augmented sixth chord resembles a second inversion chord, not the first inversion subdominant chord it is based upon. We fix this by adjusting the root. First, however, we check to see if the chord is in second inversion to begin with, otherwise it is not a Fr+6 chord. This is to avoid ChordException errors.

>>> fr6a = chord.Chord(['A-3', 'C4', 'D4', 'F#4'])
>>> fr6a.isFrenchAugmentedSixth()
True

Spelling matters:

>>> fr6b = chord.Chord(['A-3', 'C4', 'D4', 'G-4'])
>>> fr6b.isFrenchAugmentedSixth()
False

>>> fr6b = chord.Chord(['A-3', 'C4', 'E--4', 'F#4'])
>>> fr6b.isFrenchAugmentedSixth()
False

Inversion matters…

>>> fr6c = chord.Chord(['C4', 'D4', 'F#4', 'A-4'])
>>> fr6c.isFrenchAugmentedSixth()
False

Unless permitAnyInversion is True

>>> fr6c.isFrenchAugmentedSixth(permitAnyInversion=True)
True

Changed in v7: permitAnyInversion added

Chord.isGermanAugmentedSixth(*, permitAnyInversion=False) → bool

Returns True if the chord is a German augmented sixth chord (flat 6th scale degree in bass, tonic, flat third scale degree, and raised 4th).

>>> gr6a = chord.Chord(['A-3', 'C4', 'E-4', 'F#4'])
>>> gr6a.isGermanAugmentedSixth()
True

Spelling matters (see isSwissAugmentedSixth)

>>> gr6b = chord.Chord(['A-3', 'C4', 'D#4', 'F#4'])
>>> gr6b.isGermanAugmentedSixth()
False

Inversion matters…

>>> gr6c = chord.Chord(['C4', 'E-4', 'F#4', 'A-4'])
>>> gr6c.isGermanAugmentedSixth()
False

unless permitAnyInversion is True

>>> gr6c.isGermanAugmentedSixth(permitAnyInversion=True)
True

Changed in v7: permitAnyInversion added

Chord.isHalfDiminishedSeventh() → bool

Returns True if chord is a Half Diminished Seventh, that is, if it contains only notes that are either in unison with the root, a minor third above the root, a diminished fifth, or a major seventh above the root. Additionally, must contain at least one of each third, fifth, and seventh above the root. Chord must be spelled correctly. Otherwise returns false.

>>> c1 = chord.Chord(['C4', 'E-4', 'G-4', 'B-4'])
>>> c1.isHalfDiminishedSeventh()
True

Incorrectly spelled chords are not considered half-diminished sevenths >>> c2 = chord.Chord([‘C4’, ‘E-4’, ‘G-4’, ‘A#4’]) >>> c2.isHalfDiminishedSeventh() False

Nor are incomplete chords >>> c3 = chord.Chord([‘C4’, ‘G-4’, ‘B-4’]) >>> c3.isHalfDiminishedSeventh() False

>>> chord.Chord().isHalfDiminishedSeventh()
False
Chord.isIncompleteMajorTriad() → bool

Returns True if the chord is an incomplete Major triad, or, essentially, a dyad of root and major third

>>> c1 = chord.Chord(['C4', 'E3'])
>>> c1.isMajorTriad()
False
>>> c1.isIncompleteMajorTriad()
True

Note that complete major triads return False:

>>> c2 = chord.Chord(['C4', 'E3', 'G5'])
>>> c2.isIncompleteMajorTriad()
False

Remember, MAJOR Triad…

>>> c3 = chord.Chord(['C4', 'E-3'])
>>> c3.isIncompleteMajorTriad()
False

Must be spelled properly

>>> c1 = chord.Chord(['C4', 'F-4'])
>>> c1.isIncompleteMajorTriad()
False

Empty Chords return False

>>> chord.Chord().isIncompleteMajorTriad()
False
Chord.isIncompleteMinorTriad() → bool

returns True if the chord is an incomplete Minor triad, or, essentially, a dyad of root and minor third

>>> c1 = chord.Chord(['C4', 'E-3'])
>>> c1.isMinorTriad()
False
>>> c1.isIncompleteMinorTriad()
True
>>> c2 = chord.Chord(['C4', 'E-3', 'G5'])
>>> c2.isIncompleteMinorTriad()
False
Chord.isItalianAugmentedSixth(*, restrictDoublings=False, permitAnyInversion=False) → bool

Returns True if the chord is a properly spelled Italian augmented sixth chord in first inversion. Otherwise returns False.

If restrictDoublings is set to True then only the tonic may be doubled.

>>> c1 = chord.Chord(['A-4', 'C5', 'F#6'])
>>> c1.isItalianAugmentedSixth()
True

Spelling matters:

>>> c2 = chord.Chord(['A-4', 'C5', 'G-6'])
>>> c2.isItalianAugmentedSixth()
False

So does inversion:

>>> c3 = chord.Chord(['F#4', 'C5', 'A-6'])
>>> c3.isItalianAugmentedSixth()
False
>>> c4 = chord.Chord(['C5', 'A-5', 'F#6'])
>>> c4.isItalianAugmentedSixth()
False

If inversions don’t matter to you, add permitAnyInversion=True:

>>> c3.isItalianAugmentedSixth(permitAnyInversion=True)
True
>>> c4.isItalianAugmentedSixth(permitAnyInversion=True)
True

If doubling rules are turned on then only the tonic can be doubled:

>>> c4 = chord.Chord(['A-4', 'C5', 'F#6', 'C6', 'C7'])
>>> c4.isItalianAugmentedSixth(restrictDoublings=True)
True
>>> c5 = chord.Chord(['A-4', 'C5', 'F#6', 'C5', 'F#7'])
>>> c5.isItalianAugmentedSixth(restrictDoublings=True)
False
>>> c5.isItalianAugmentedSixth(restrictDoublings=False)
True

Changed in v7. restrictDoublings is keyword only. Added permitAnyInversion.

Chord.isMajorTriad()

Returns True if chord is a Major Triad, that is, if it contains only notes that are either in unison with the root, a major third above the root, or a perfect fifth above the root. Additionally, must contain at least one of each third and fifth above the root. Chord must be spelled correctly. Otherwise returns false.

Example:

>>> cChord = chord.Chord(['C', 'E', 'G'])
>>> other = chord.Chord(['C', 'G'])
>>> cChord.isMajorTriad()
True
>>> other.isMajorTriad()
False

Notice that the proper spelling of notes is crucial

>>> chord.Chord(['B-', 'D', 'F']).isMajorTriad()
True
>>> chord.Chord(['A#', 'D', 'F']).isMajorTriad()
False

(See: forteClassTn() to catch this case; major triads in the forte system are 3-11B no matter how they are spelled.)

>>> chord.Chord(['A#', 'D', 'F']).forteClassTn == '3-11B'
True
Chord.isMinorTriad()

Returns True if chord is a Minor Triad, that is, if it contains only notes that are either in unison with the root, a minor third above the root, or a perfect fifth above the root. Additionally, must contain at least one of each third and fifth above the root. Chord must be spelled correctly. Otherwise returns false.

Example:

>>> cChord = chord.Chord(['C', 'E-', 'G'])
>>> cChord.isMinorTriad()
True
>>> other = chord.Chord(['C', 'E', 'G'])
>>> other.isMinorTriad()
False
Chord.isNinth()

Returns True if chord contains at least one of each of Third, Fifth, Seventh, and Ninth and every note in the chord is a Third, Fifth, Seventh, or Ninth, such that there are no repeated scale degrees (ex: E and E-). Else return false.

Example:

>>> cChord = chord.Chord(['C', 'E', 'G', 'B', 'D'])
>>> cChord.isNinth()
True
>>> other = chord.Chord(['C', 'E', 'F', 'G', 'B'])
>>> other.isNinth()
False
Chord.isSeventh()

Returns True if chord contains at least one of each of Third, Fifth, and Seventh, and every note in the chord is a Third, Fifth, or Seventh, such that there are no repeated scale degrees (ex: E and E-). Else return false.

Example:

>>> cChord = chord.Chord(['C', 'E', 'G', 'B'])
>>> cChord.isSeventh()
True
>>> other = chord.Chord(['C', 'D', 'E', 'F', 'G', 'B'])
>>> other.isSeventh()
False
Chord.isSeventhOfType(intervalArray)

Returns True if chord is a seventh chord of a particular type as specified by intervalArray. For instance .isDiminishedSeventh() is just a thin wrapper around .isSeventhOfType([0, 3, 6, 9]) and isDominantSeventh() has intervalArray([0, 4, 7, 10])

intervalArray can be any iterable.

Though it checks on intervalArray, it does make sure that it is a seventh chord, not D–, D##, G, B-

>>> chord.Chord('C E G B-').isSeventhOfType((0, 4, 7, 10))
True
>>> chord.Chord('C E G B-').isSeventhOfType((0, 3, 7, 10))
False
>>> chord.Chord('D-- D## G B-').isSeventhOfType((0, 4, 7, 10))
False
Chord.isSwissAugmentedSixth(*, permitAnyInversion=False)

Returns true is it is a respelled German augmented 6th chord with sharp 2 instead of flat 3. This chord has many names, Swiss Augmented Sixth, Alsatian Chord, English A6, Norwegian, etc. as well as doubly-augmented sixth, which is a bit of a misnomer since it is the 4th that is doubly augmented, not the sixth.

>>> chord.Chord('A-4 C5 D#5 F#6').isSwissAugmentedSixth()
True

Respelled as a German Augmented Sixth does not count:

>>> chord.Chord('A-4 C5 E-5 F#6').isSwissAugmentedSixth()
False

Inversions matter:

>>> ch3 = chord.Chord('F#4 D#5 C6 A-6')
>>> ch3.isSwissAugmentedSixth()
False

unless permitAnyInversion is given:

>>> ch3.isSwissAugmentedSixth(permitAnyInversion=True)
True

Changed in v7: permitAnyInversion added

Chord.isTranspositionallySymmetrical(*, requireIntervallicEvenness=False) → bool

Returns True if the Chord is symmetrical under transposition and False otherwise. A pitch-class-based way of looking at this, is can all the pitch classes be transposed up some number of semitones 1-11 and end up with the same pitch-classes. Like the dyad F-B can have each note transposed up 6 semitones and get another B-F = F-B dyad.

A tonally-focused way of looking at this would be to ask, “Are we unable to distinguish root position vs. some inversion of the basic chord by ear alone?” For instance, we can see (visually) that C-Eb-Gb-Bbb is a diminished-seventh chord in root position, while Eb-Gb-Bbb-C is a diminished-seventh in first inversion. But if the chord were heard in isolation it would not be possible to tell the inversion at all, since diminished-sevenths are transpositionally symmetrical.

With either way of looking at it, there are fourteen set classes of 2-10 pitch classes have this property, including the augmented triad:

>>> chord.Chord('C E G#').isTranspositionallySymmetrical()
True

…but not the major triad:

>>> chord.Chord('C E G').isTranspositionallySymmetrical()
False

The whole-tone scale and the Petrushka chord are both transpositionally symmetrical:

>>> wholeToneAsChord = chord.Chord('C D E F# G# B- C')
>>> wholeToneAsChord.isTranspositionallySymmetrical()
True

>>> petrushka = chord.Chord([0, 1, 3, 6, 7, 9])
>>> petrushka.isTranspositionallySymmetrical()
True

If requireIntervallicEvenness is True then only chords that also have even spacing / evenly divide the octave are considered transpositionally symmetrical. The normal cases are the F-B (06) dyad, the augmented triad, the diminished-seventh chord, and the whole-tone scale collection:

>>> wholeToneAsChord.isTranspositionallySymmetrical(requireIntervallicEvenness=True)
True

>>> petrushka.isTranspositionallySymmetrical(requireIntervallicEvenness=True)
False

Note that complements of these chords (except the whole-tone collection) are not transpositionally symmetrical if requireIntervallicEvenness is required:

>>> chord.Chord([0, 4, 8]).isTranspositionallySymmetrical(requireIntervallicEvenness=True)
True

>>> chord.Chord([1, 2, 3, 5, 6, 7, 9, 10, 11]).isTranspositionallySymmetrical(
...       requireIntervallicEvenness=True)
False

Empty chords and the total aggregate cannot have their inversion determined by ear alone. So they are True with or without requireIntervallicEvenness.

>>> chord.Chord().isTranspositionallySymmetrical()
True

>>> chord.Chord(list(range(12))).isTranspositionallySymmetrical()
True

Monads (single-note “chords”) cannot be transposed 1-11 semitones to recreate themselves, so they return False by default:

>>> chord.Chord('C').isTranspositionallySymmetrical()
False

But they are the only case where requireIntervallicEvenness actually switches from False to True, because they do evenly divide the octave.

>>> chord.Chord('C').isTranspositionallySymmetrical(requireIntervallicEvenness=True)
True

11-note chords return False in either case:

>>> chord.Chord(list(range(11))).isTranspositionallySymmetrical()
False
Chord.isTriad() → bool

Returns True if this Chord is a triad of some sort. It could even be a rather exotic triad so long as the chord contains at least one Third and one Fifth and all notes have the same name as one of the three notes.

Note: only returns True if triad is spelled correctly.

Note the difference of “containsTriad” vs. “isTriad”: A dominant-seventh chord is NOT a triad, but it contains two triads.

>>> cChord = chord.Chord(['C4', 'E4', 'A4'])
>>> cChord.isTriad()
True

>>> other = chord.Chord(['C', 'D', 'E', 'F', 'G'])
>>> other.isTriad()
False

>>> incorrectlySpelled = chord.Chord(['C', 'D#', 'G'])
>>> incorrectlySpelled.isTriad()
False

>>> incorrectlySpelled.pitches[1].getEnharmonic(inPlace=True)
>>> incorrectlySpelled
<music21.chord.Chord C E- G>
>>> incorrectlySpelled.isTriad()
True
Chord.removeRedundantPitchClasses(*, inPlace=False)

Remove all but the FIRST instance of a pitch class with more than one instance of that pitch class.

If inPlace is True, a copy is not made and a list of deleted pitches is returned; otherwise a copy is made and that copy is returned.

>>> c1 = chord.Chord(['c2', 'e3', 'g4', 'e3'])
>>> removed = c1.removeRedundantPitchClasses(inPlace=True)
>>> c1.pitches
(<music21.pitch.Pitch C2>, <music21.pitch.Pitch E3>, <music21.pitch.Pitch G4>)

>>> c2 = chord.Chord(['c5', 'e3', 'g4', 'c2', 'e3', 'f-4'])
>>> removed = c2.removeRedundantPitchClasses(inPlace=True)
>>> c2.pitches
(<music21.pitch.Pitch C5>, <music21.pitch.Pitch E3>, <music21.pitch.Pitch G4>)

Changed in v.6 – inPlace defaults to False.

Chord.removeRedundantPitchNames(*, inPlace=False)

Remove all but the FIRST instance of a pitch class with more than one instance of that pitch name regardless of octave (but note that spelling matters, so that in the example, the F-flat stays even though there is already an E.)

If inPlace is True, a copy is not made and a list of deleted pitches is returned; otherwise a copy is made and that copy is returned.

>>> c2 = chord.Chord(['c5', 'e3', 'g4', 'c2', 'e3', 'f-4'])
>>> c2
<music21.chord.Chord C5 E3 G4 C2 E3 F-4>

>>> rem = c2.removeRedundantPitchNames(inPlace=True)
>>> c2
<music21.chord.Chord C5 E3 G4 F-4>
>>> rem
[<music21.pitch.Pitch C2>, <music21.pitch.Pitch E3>]

Changed in v.6 – inPlace defaults to False.

Chord.removeRedundantPitches(*, inPlace=False)

Remove all but one instance of a pitch that appears twice.

It removes based on the name of the note and the octave, so the same note name in two different octaves is retained.

If inPlace is True, a copy is not made and a list of deleted pitches is returned; otherwise a copy is made and that copy is returned.

>>> c1 = chord.Chord(['c2', 'e3', 'g4', 'e3'])
>>> c1
<music21.chord.Chord C2 E3 G4 E3>

>>> removedList = c1.removeRedundantPitches(inPlace=True)
>>> c1
<music21.chord.Chord C2 E3 G4>
>>> removedList
[<music21.pitch.Pitch E3>]

>>> c1.forteClass
'3-11B'

>>> c2 = chord.Chord(['c2', 'e3', 'g4', 'c5'])
>>> c2c = c2.removeRedundantPitches(inPlace=False)
>>> c2c
<music21.chord.Chord C2 E3 G4 C5>

It is a known bug that because pitch.nameWithOctave gives the same value for B-flat in octave 1 as B-natural in octave negative 1, negative octaves can screw up this method. With all the things left to do for music21, it doesn’t seem a bug worth squashing at this moment, but FYI:

>>> p1 = pitch.Pitch('B-')
>>> p1.octave = 1
>>> p2 = pitch.Pitch('B')
>>> p2.octave = -1
>>> c3 = chord.Chord([p1, p2])
>>> removedPitches = c3.removeRedundantPitches(inPlace=True)
>>> c3.pitches
(<music21.pitch.Pitch B-1>,)

>>> c3.pitches[0].name
'B-'
>>> c3.pitches[0].octave
1
>>> removedPitches
[<music21.pitch.Pitch B-1>]
>>> removedPitches[0].name
'B'
>>> removedPitches[0].octave
-1

The first pitch survives:

>>> c3.pitches[0] is p1
True

>>> c3.pitches[0] is p2
False

Changed in v.6 – inPlace defaults to False.

Chord.root(newroot: None = None, *, find: bool | None = None) → Pitch
Chord.root(newroot: str | Pitch | Note, *, find: bool | None = None) → None

Returns the root of the chord. Or if given a Pitch as the newroot will override the algorithm and always return that Pitch.

>>> cmaj = chord.Chord(['E3', 'C4', 'G5'])
>>> cmaj.root()
<music21.pitch.Pitch C4>

Examples:

>>> cmaj = chord.Chord(['E', 'G', 'C'])
>>> cmaj.root()
<music21.pitch.Pitch C>

For some chords we make an exception. For instance, this chord in B-flat minor:

>>> aDim7no3rd = chord.Chord(['A3', 'E-4', 'G4'])

…could be considered a type of E-flat 11 chord with a 3rd, but no 5th, 7th, or 9th, in 5th inversion. That doesn’t make sense, so we should call it an A dim 7th chord with no 3rd.

>>> aDim7no3rd.root()
<music21.pitch.Pitch A3>

>>> aDim7no3rdInv = chord.Chord(['E-3', 'A4', 'G4'])
>>> aDim7no3rdInv.root()
<music21.pitch.Pitch A4>

The root of a 13th chord (which could be any chord in any inversion) is designed to be the bass:

>>> chord.Chord('F3 A3 C4 E-4 G-4 B4 D5').root()
<music21.pitch.Pitch F3>

Multiple pitches in different octaves do not interfere with root.

>>> lotsOfNotes = chord.Chord(['E3', 'C4', 'G4', 'B-4', 'E5', 'G5'])
>>> r = lotsOfNotes.root()
>>> r
<music21.pitch.Pitch C4>

>>> r is lotsOfNotes.pitches[1]
True

Setting of a root may happen for a number of reasons, such as in the case where music21’s idea of a root differs from the interpreter’s.

To specify the root directly, pass the pitch to the root function:

>>> cSus4 = chord.Chord('C4 F4 G4')
>>> cSus4.root()  # considered by music21 to be an F9 chord in 2nd inversion
<music21.pitch.Pitch F4>

Change it to be a Csus4:

>>> cSus4.root('C4')
>>> cSus4.root()
<music21.pitch.Pitch C4>

Note that if passing in a string as the root, the root is set to a pitch in the chord if possible.

>>> cSus4.root() is cSus4.pitches[0]
True

You might also want to supply an “implied root.” For instance, some people call a diminished seventh chord (generally viio7) a dominant chord with an omitted root (Vo9) – here we will specify the root to be a note not in the chord:

>>> vo9 = chord.Chord(['B3', 'D4', 'F4', 'A-4'])
>>> vo9.root()
<music21.pitch.Pitch B3>

>>> vo9.root(pitch.Pitch('G3'))
>>> vo9.root()
<music21.pitch.Pitch G3>

When setting a root, the pitches of the chord are left untouched:

>>> [p.nameWithOctave for p in vo9.pitches]
['B3', 'D4', 'F4', 'A-4']

By default, this method uses an algorithm to find the root among the chord’s pitches, if no root has been previously specified. If a root has been explicitly specified, as in the Csus4 chord above, it can be returned to the original root() by setting find explicitly to True:

>>> cSus4.root(find=True)
<music21.pitch.Pitch F4>

Subsequent calls without find=True have also removed the overridden root:

>>> cSus4.root()
<music21.pitch.Pitch F4>

If for some reason you do not want the root-finding algorithm to be run (for instance, checking to see if an overridden root has been specified) set find=False. “None” will be returned if no root has been specified.

>>> c = chord.Chord(['E3', 'G3', 'B4'])
>>> print(c.root(find=False))
None

Chord symbols, for instance, have their root already specified on construction:

>>> d = harmony.ChordSymbol('CM/E')
>>> d.root(find=False)
<music21.pitch.Pitch C4>

There is no need to set find=False in this case, however, the algorithm will skip the slow part of finding the root if it has been specified (or already found and no pitches have changed).

A chord with no pitches has no root and raises a ChordException.

>>> chord.Chord().root()
Traceback (most recent call last):
music21.chord.ChordException: no pitches in chord <music21.chord.Chord ...>

Changed in v5.2 – find is a keyword-only parameter, newroot finds pitch in chord

Chord.semiClosedPosition(*, forceOctave, inPlace: Literal[True], leaveRedundantPitches=False) → None
Chord.semiClosedPosition(*, forceOctave=None, inPlace: Literal[False] = False, leaveRedundantPitches=False) → _ChordType

Similar to ClosedPosition() in that it moves everything within an octave EXCEPT if there’s already a pitch at that step, then it puts it up an octave. It’s a very useful display standard for dense post-tonal chords.

>>> c1 = chord.Chord(['C3', 'E5', 'C#6', 'E-7', 'G8', 'C9', 'E#9'])
>>> c2 = c1.semiClosedPosition(inPlace=False)
>>> c2
<music21.chord.Chord C3 E-3 G3 C#4 E4 E#5>

leaveRedundantPitches still works, and gives them a new octave!

>>> c3 = c1.semiClosedPosition(
...     inPlace=False,
...     leaveRedundantPitches=True,
...     )
>>> c3
<music21.chord.Chord C3 E-3 G3 C4 E4 C#5 E#5>

of course forceOctave still works, as does inPlace=True.

>>> c1.semiClosedPosition(
...     forceOctave=2,
...     inPlace=True,
...     leaveRedundantPitches=True,
...     )
>>> c1
<music21.chord.Chord C2 E-2 G2 C3 E3 C#4 E#4>
Chord.semitonesFromChordStep(chordStep, testRoot=None)

Returns the number of semitones (mod12) above the root that the chordStep lies (i.e., 3 = third of the chord; 5 = fifth, etc.) if one exists. Or None if it does not exist.

You can optionally specify a note.Note object to try as the root. It does not change the Chord.root object. We use these methods to figure out what the root of the triad is.

Currently, there is a bug that in the case of a triply diminished third (e.g., “c” => “e—-“), this function will incorrectly claim no third exists. Perhaps this should be construed as a feature.

In the case of chords such as C, E-, E, semitonesFromChordStep(3) will return the number for the first third, in this case 3. It will not return 4, nor a list object (3, 4). You probably do not want to be using tonal chord manipulation functions on chords such as these anyway. Check for such cases with chord.hasAnyRepeatedDiatonicNote first.

Tools with the expression “chordStep” in them refer to the diatonic third, fifth, etc., of the chord. They have little to do with the scale degree of the scale or key that the chord is embedded within. See “chord.scaleDegrees” for this functionality.

>>> cChord = chord.Chord(['E3', 'C4', 'G5'])
>>> cChord.semitonesFromChordStep(3)  # distance from C to E
4

>>> cChord.semitonesFromChordStep(5)  # C to G
7

Omitted chordSteps return None

>>> print(cChord.semitonesFromChordStep(6))
None

Note that the routine returns the semitones to the FIRST third. This chord has two thirds, C and C#

>>> aChord = chord.Chord(['a2', 'c4', 'c#5', 'e#7'])
>>> aChord.semitonesFromChordStep(3)
3

>>> aChord.semitonesFromChordStep(5)
8
>>> print(aChord.semitonesFromChordStep(2))
None

Test whether this strange chord gets the B# as 0 semitones:

>>> c = chord.Chord(['C4', 'E4', 'G4', 'B#4'])
>>> c.semitonesFromChordStep(7)
0

If testRoot is set to a Pitch object then that note is used as the root of the chord regardless of anything else that might be considered.

A-minor: 1st inversion.

>>> aMin = chord.Chord(['C4', 'E4', 'A4'])
>>> aMin.semitonesFromChordStep(3)
3
>>> aMin.semitonesFromChordStep(5)
7

C6 chord, jazz like, root position:

>>> cPitch = pitch.Pitch('C4')
>>> c6 = aMin  # renaming for clarity
>>> c6.semitonesFromChordStep(3, testRoot = cPitch)
4
>>> c6.semitonesFromChordStep(5, testRoot = cPitch) is None
True
>>> c6.semitonesFromChordStep(6, testRoot = cPitch)
9
Chord.setColor(value, pitchTarget=None)

Set color for specific pitch.

>>> c = chord.Chord('C4 E4 G4')
>>> c.setColor('red', 'C4')
>>> c['0.style.color']
'red'
>>> c.setColor('blue')  # set for whole chord...
>>> c.style.color
'blue'
>>> c['E4.style.color']
'blue'

>>> c.setColor('red', 'C9')
Traceback (most recent call last):
music21.chord.ChordException: the given pitch is not in the Chord: C9
Chord.setNotehead(nh, pitchTarget)

Given a notehead attribute as a string and a pitch object in this Chord, set the notehead attribute of that pitch to the value of that notehead. Valid notehead type names are found in note.noteheadTypeNames (see below):

>>> for noteheadType in note.noteheadTypeNames:
...    noteheadType
...
'arrow down'
'arrow up'
'back slashed'
'circle dot'
'circle-x'
'circled'
'cluster'
'cross'
'diamond'
'do'
'fa'
'inverted triangle'
'la'
'left triangle'
'mi'
'none'
'normal'
'other'
're'
'rectangle'
'slash'
'slashed'
'so'
'square'
'ti'
'triangle'
'x'

>>> n1 = note.Note('D4')
>>> n2 = note.Note('G4')
>>> c1 = chord.Chord([n1, n2])
>>> c1.setNotehead('diamond', c1.pitches[1])  # just to g
>>> c1.getNotehead(c1.pitches[1])
'diamond'

>>> c1.getNotehead(c1.pitches[0])
'normal'

If a chord has two of the same pitch, but each associated with a different notehead, then object equality must be used to distinguish between the two.

>>> c2 = chord.Chord(['D4', 'D4'])
>>> secondD4 = c2.pitches[1]
>>> c2.setNotehead('diamond', secondD4)
>>> for i in [0, 1]:
...     c2.getNotehead(c2.pitches[i])
...
'normal'
'diamond'

By default, assigns to first pitch:

>>> c3 = chord.Chord('C3 F4')
>>> c3.setNotehead('slash', None)
>>> c3['0.notehead']
'slash'

Less safe to match by string, but possible:

>>> c3.setNotehead('so', 'F4')
>>> c3['1.notehead']
'so'

Error:

>>> c3.setNotehead('so', 'G4')
Traceback (most recent call last):
music21.chord.ChordException: the given pitch is not in the Chord: G4
Chord.setNoteheadFill(nh, pitchTarget)

Given a noteheadFill attribute as a string and a pitch object in this Chord, set the noteheadFill attribute of that pitch to the value of that notehead. Valid noteheadFill names are True, False, None (default)

>>> n1 = note.Note('D4')
>>> n2 = note.Note('G4')
>>> c1 = chord.Chord([n1, n2])
>>> c1.setNoteheadFill(False, c1.pitches[1])  # just to g
>>> c1.getNoteheadFill(c1.pitches[1])
False

>>> c1.getNoteheadFill(c1.pitches[0]) is None
True

If a chord has two of the same pitch, but each associated with a different notehead, then object equality must be used to distinguish between the two.

>>> c2 = chord.Chord(['D4', 'D4'])
>>> secondD4 = c2.pitches[1]
>>> c2.setNoteheadFill(False, secondD4)
>>> for i in [0, 1]:
...     print(c2.getNoteheadFill(c2.pitches[i]))
...
None
False

By default assigns to first pitch:

>>> c3 = chord.Chord('C3 F4')
>>> c3.setNoteheadFill(False, None)
>>> c3['0.noteheadFill']
False

Less safe to match by string, but possible:

>>> c3.setNoteheadFill(True, 'F4')
>>> c3['1.noteheadFill']
True

Error: >>> c3.setNoteheadFill(True, ‘G4’) Traceback (most recent call last): music21.chord.ChordException: the given pitch is not in the Chord: G4

Chord.setStemDirection(stem, pitchTarget)

Given a stem attribute as a string and a pitch object in this Chord, set the stem attribute of that pitch to the value of that stem. Valid stem directions are found note.stemDirectionNames (see below).

>>> for name in note.stemDirectionNames:
...     name
...
'double'
'down'
'noStem'
'none'
'unspecified'
'up'

>>> n1 = note.Note('D4')
>>> n2 = note.Note('G4')
>>> c1 = chord.Chord([n1, n2])
>>> c1.setStemDirection('double', c1.pitches[1])  # just to g
>>> c1.getStemDirection(c1.pitches[1])
'double'

>>> c1.getStemDirection(c1.pitches[0])
'unspecified'

If a chord has two of the same pitch, but each associated with a different stem, then object equality must be used to distinguish between the two.

>>> c2 = chord.Chord(['D4', 'D4'])
>>> secondD4 = c2.pitches[1]
>>> c2.setStemDirection('double', secondD4)
>>> for i in [0, 1]:
...    print(c2.getStemDirection(c2.pitches[i]))
...
unspecified
double

By default, assigns to first pitch:

>>> c3 = chord.Chord('C3 F4')
>>> c3.setStemDirection('down', None)
>>> c3['0.stemDirection']
'down'

Less safe to match by string, but possible:

>>> c3.setStemDirection('down', 'F4')
>>> c3['1.stemDirection']
'down'

Error: >>> c3.setStemDirection(‘up’, ‘G4’) Traceback (most recent call last): music21.chord.ChordException: the given pitch is not in the Chord: G4

Chord.setTie(tieObjOrStr: Tie | str, pitchTarget)

Given a tie object (or a tie type string) and a pitch or Note in this Chord, set the pitch’s tie attribute in this chord to that tie type.

>>> c1 = chord.Chord(['d3', 'e-4', 'b-4'])
>>> t1 = tie.Tie('start')
>>> c1.setTie(t1, 'b-4')  # or it can be done with a pitch.Pitch object
>>> c1.getTie(c1.pitches[2]) is t1
True

Setting a tie with a chord with the same pitch twice requires getting the exact pitch object out to be sure which one…

>>> c2 = chord.Chord(['D4', 'D4'])
>>> secondD4 = c2.pitches[1]
>>> c2.setTie('start', secondD4)
>>> for i in [0, 1]:
...    print(c2.getTie(c2.pitches[i]))
...
None
<music21.tie.Tie start>

>>> c3 = chord.Chord('C3 F4')
>>> c3.setTie('start', None)
>>> c3.getTie(c3.pitches[0])
<music21.tie.Tie start>

Less safe to match by string, because there might be multiple pitches with the same name in the chord, but possible:

>>> c4 = chord.Chord('D4 F#4')
>>> c4.setTie('start', 'F#4')
>>> c4.getTie('F#4')
<music21.tie.Tie start>

Setting a tie on a note not in the chord is an error:

>>> c3.setTie('stop', 'G4')
Traceback (most recent call last):
music21.chord.ChordException: the given pitch is not in the Chord: G4
Chord.setVolume(vol: music21.volume.Volume, target: t.Union[str, note.Note, pitch.Pitch])

Set the Volume object of a specific Pitch.

Changed in v.8 – after appearing in ChordBase in v.7, it has been properly

moved back to Chord itself. The ability to change just the first note’s volume has been removed. Use Chord().volume = vol to change the volume for a whole chord.

Chord.simplifyEnharmonics(*, inPlace=False, keyContext=None)

Calls pitch.simplifyMultipleEnharmonics on the pitches of the chord.

Simplifies the enharmonics in the sense of making a more logical chord. Note below that E# is added there because C# major is simpler than C# F G#.

>>> c = chord.Chord('C# F G#')
>>> c.pitches
(<music21.pitch.Pitch C#>, <music21.pitch.Pitch F>, <music21.pitch.Pitch G#>)

>>> c.simplifyEnharmonics(inPlace=True)
>>> c.pitches
(<music21.pitch.Pitch C#>, <music21.pitch.Pitch E#>, <music21.pitch.Pitch G#>)

If keyContext is provided the enharmonics are simplified based on the supplied Key or KeySignature.

>>> c.simplifyEnharmonics(inPlace=True, keyContext=key.Key('A-'))
>>> c.pitches
(<music21.pitch.Pitch D->, <music21.pitch.Pitch F>, <music21.pitch.Pitch A->)
Chord.sortAscending(*, inPlace=False)
Chord.sortChromaticAscending()

Same as sortAscending but notes are sorted by midi number, so F## sorts above G-.

Chord.sortDiatonicAscending(*, inPlace=False)

The notes are sorted by Scale degree and then by Offset (so F## sorts below G-). Notes that are the identical pitch retain their order

After talking with Daniel Jackson, let’s try to make the chord object as immutable as possible, so we return a new Chord object with the notes arranged from lowest to highest

>>> cMajUnsorted = chord.Chord(['E4', 'C4', 'G4'])
>>> cMajSorted = cMajUnsorted.sortDiatonicAscending()
>>> cMajSorted.pitches[0].name
'C'

>>> c2 = chord.Chord(['E4', 'C4', 'G4'])
>>> c2.sortDiatonicAscending(inPlace=True)
>>> c2
<music21.chord.Chord C4 E4 G4>

Changed in v.6 – if inPlace is True do not return anything.

Chord.sortFrequencyAscending()

Same as above, but uses a note’s frequency to determine height; so that C# would be below D- in 1/4-comma meantone, equal in equal temperament, but below it in (most) just intonation types.

Chord.transpose(value, *, inPlace=False)

Transpose the Chord by the user-provided value. If the value is an integer, the transposition is treated in half steps and enharmonics might be simplified (not done yet). If the value is a string, any Interval string specification can be provided.

If inPlace is set to True (default = False) then the original chord is changed. Otherwise a new Chord is returned.

We take a three-note chord (G, A, C#) and transpose it up a minor third, getting the chord B-flat, C, E.

>>> a = chord.Chord(['g4', 'a3', 'c#6'])
>>> b = a.transpose('m3')
>>> b
<music21.chord.Chord B-4 C4 E6>

Here we create the interval object first (rather than giving a string) and specify transposing down six semitones, instead of saying A-4.

>>> aInterval = interval.Interval(-6)
>>> b = a.transpose(aInterval)
>>> b
<music21.chord.Chord C#4 E-3 G5>

If inPlace is True then rather than returning a new chord, the chord itself is changed.

>>> a.transpose(aInterval, inPlace=True)
>>> a
<music21.chord.Chord C#4 E-3 G5>

Methods inherited from ChordBase:

Methods inherited from NotRest:

Methods inherited from GeneralNote:

Methods inherited from Music21Object:

Methods inherited from ProtoM21Object:

Chord instance variables

Chord.beams

A Beams object that contains information about the beaming of this note.

Chord.isChord

Boolean read-only value describing if this GeneralNote object is a Chord. Is True

Chord.isNote

Boolean read-only value describing if this GeneralNote object is a Note. Is False

Chord.isRest

Boolean read-only value describing if this GeneralNote object is a Rest. Is False

>>> c = chord.Chord()
>>> c.isRest
False

Instance variables inherited from ChordBase:

Instance variables inherited from NotRest:

Instance variables inherited from GeneralNote:

Instance variables inherited from Music21Object:

ChordBase

class music21.chord.ChordBase(notes: None | str | Sequence[str] | Sequence[Pitch] | Sequence[NotRest] | Sequence[int] = None, **keywords)

A base class for NotRest objects that have multiple underlying structures like notes or unpitched percussion.

As of Version 7, ChordBase lies between Chord and NotRest in the music21 hierarchy, so that features can be shared with PercussionChord.

ChordBase bases

ChordBase read-only properties

ChordBase.notes

Read-only properties inherited from GeneralNote:

Read-only properties inherited from Music21Object:

Read-only properties inherited from ProtoM21Object:

ChordBase read/write properties

ChordBase.tie

Get or set a single tie based on all the ties in this Chord.

This overloads the behavior of the tie attribute found in all NotRest classes.

If setting a tie, tie is applied to all pitches.

>>> c1 = chord.Chord(['c4', 'g4'])
>>> tie1 = tie.Tie('start')
>>> c1.tie = tie1
>>> c1.tie
<music21.tie.Tie start>

>>> c1.getTie(c1.pitches[1])
<music21.tie.Tie start>
ChordBase.volume

Get or set the Volume object for this Chord.

When setting the .volume property, all pitches are treated as having the same Volume object.

>>> c = chord.Chord(['g#', 'd-'])
>>> c.volume
<music21.volume.Volume realized=0.71>

>>> c.volume = volume.Volume(velocity=64)
>>> c.volume.velocityIsRelative = False
>>> c.volume
<music21.volume.Volume realized=0.5>
Changed in v.8 – setting volume to a list of volumes is no longer supported.

See setVolumes() instead

Read/write properties inherited from NotRest:

Read/write properties inherited from GeneralNote:

Read/write properties inherited from Music21Object:

ChordBase methods

ChordBase.__eq__(other)

True if the ChordBase passes all super() equality tests and the pitches (or display pitches, for Unpitched objects) are the same (but possibly in a different order).

>>> c1 = chord.Chord('C4 E4 G4')
>>> c2 = chord.Chord('E4 C4 G4')
>>> c1 == c2
True
>>> c3 = chord.Chord('E4 C#4 G4')
>>> c2 == c3
False
>>> n1 = note.Note('C4')
>>> c1 == n1
False
>>> c2.duration.quarterLength = 2.0
>>> c1 == c2
False
>>> c1 != c2
True
ChordBase.add(notes) → None

Add a Note, Pitch, the .notes of another chord, or string representing a Pitch, or a list of any-of-the-above types to a Chord or PercussionChord.

Does no sorting. That is on the Chord object.

>>> c = chord.Chord('C4 E4 G4')
>>> c.add('B3')
>>> c
<music21.chord.Chord B3 C4 E4 G4>
>>> c.duration
<music21.duration.Duration 1.0>

>>> c.add('A2', runSort=False)
>>> c
<music21.chord.Chord B3 C4 E4 G4 A2>

>>> c.add(['B5', 'C6'])
>>> c
<music21.chord.Chord A2 B3 C4 E4 G4 B5 C6>

>>> c.add(pitch.Pitch('D6'))
>>> c
<music21.chord.Chord A2 B3 C4 E4 G4 B5 C6 D6>

>>> n = note.Note('E6')
>>> n.duration.type = 'half'
>>> c.add(n)
>>> c
<music21.chord.Chord A2 B3 C4 E4 G4 B5 C6 D6 E6>
>>> c.duration
<music21.duration.Duration 1.0>
>>> c[-1]
<music21.note.Note E>
>>> c[-1].duration
<music21.duration.Duration 2.0>
ChordBase.hasComponentVolumes() → bool

Utility method to determine if this object has component Volume objects assigned to each note-component.

>>> c1 = chord.Chord(['c4', 'd-1', 'g6'])
>>> c1.setVolumes([60, 20, 120])
>>> [n.volume.velocity for n in c1]
[60, 20, 120]

>>> c1.hasComponentVolumes()
True

>>> c2 = chord.Chord(['c4', 'd-1', 'g6'])
>>> c2.volume.velocity = 23
>>> c2.hasComponentVolumes()
False

>>> c3 = chord.Chord(['c4', 'd-1', 'g6'])
>>> c3.setVolumes([0.2, 0.5, 0.8])
>>> [n.volume.velocity for n in c3]
[25, 64, 102]

>>> c4 = chord.Chord(['c4', 'd-1', 'g6'])
>>> c4.volume = 89
>>> c4.volume.velocity
89

>>> c4.hasComponentVolumes()
False
ChordBase.remove(removeItem)

Removes a note or pitch from the chord. Must be a pitch equal to a pitch in the chord or a string specifying the pitch name with octave or a note from a chord. If not found, raises a ValueError

>>> c = chord.Chord('C4 E4 G4')
>>> c.remove('E4')
>>> c
<music21.chord.Chord C4 G4>
>>> c.remove('D5')
Traceback (most recent call last):
ValueError: Chord.remove(x), x not in chord

>>> c = chord.Chord('C4 E4 G4')
>>> c.remove(pitch.Pitch('E4'))
>>> c
<music21.chord.Chord C4 G4>
>>> c.remove(pitch.Pitch('F#5'))
Traceback (most recent call last):
ValueError: Chord.remove(x), x not in chord

The Note also does not need to be the exact note of the chord, just matches on equality

>>> c = chord.Chord('C4 E4 G4')
>>> c.remove(note.Note('E4'))
>>> c
<music21.chord.Chord C4 G4>

>>> c.remove(c[1])
>>> c
<music21.chord.Chord C4>

>>> c.remove(note.Note('B-2'))
Traceback (most recent call last):
ValueError: Chord.remove(x), x not in chord

>>> c.remove(4)
Traceback (most recent call last):
ValueError: Cannot remove 4 from a chord; try a Pitch or Note object

Like Python’s list object does not work on lists…

>>> c = chord.Chord('C4 E4 G4')
>>> c.remove(['C4', 'E4'])
Traceback (most recent call last):
ValueError: Cannot remove ['C4', 'E4'] from a chord; try a Pitch or Note object
ChordBase.setVolumes(volumes: t.Sequence[t.Union['music21.volume.Volume', int, float]])

Set as many individual volumes as appear in volumes. If there are not enough volumes, then cycles through the list of volumes here:

>>> c = chord.Chord(['g#', 'd-'])
>>> c.setVolumes([volume.Volume(velocity=96), volume.Volume(velocity=96)])
>>> c.hasComponentVolumes()
True

Note that this means that the chord itself does not have a volume at this moment!

>>> c.hasVolumeInformation()
False

>>> c.volume.velocity
96

But after having called the volume, now it does:

>>> c.hasVolumeInformation()
True

>>> c.volume.velocityIsRelative = False
>>> c.volume
<music21.volume.Volume realized=0.76>

New in v.8 – replaces setting .volume to a list

Methods inherited from NotRest:

Methods inherited from GeneralNote:

Methods inherited from Music21Object:

Methods inherited from ProtoM21Object:

ChordBase instance variables

ChordBase.beams

A Beams object that contains information about the beaming of this note.

ChordBase.isNote

Boolean read-only value describing if this GeneralNote object is a Note. Is False

ChordBase.isRest

Boolean read-only value describing if this GeneralNote object is a Rest. Is False

>>> c = chord.Chord()
>>> c.isRest
False

Instance variables inherited from NotRest:

Instance variables inherited from GeneralNote:

Instance variables inherited from Music21Object:

Functions

music21.chord.fromForteClass(notation: str | Sequence[int]) → Chord

Return a Chord given a Forte-class notation. The Forte class can be specified as string (e.g., 3-11) or as a list of cardinality and number (e.g., [8, 1]).

If no match is available, None is returned.

>>> chord.fromForteClass('3-11')
<music21.chord.Chord C E- G>

>>> chord.fromForteClass('3-11b')
<music21.chord.Chord C E G>

>>> chord.fromForteClass('3-11a')
<music21.chord.Chord C E- G>

>>> chord.fromForteClass((11, 1))
<music21.chord.Chord C D- D E- E F G- G A- A B->
music21.chord.fromIntervalVector(notation, getZRelation=False)

Return one or more Chords given an interval vector.

>>> chord.fromIntervalVector([0, 0, 0, 0, 0, 1])
<music21.chord.Chord C F#>

>>> chord.fromIntervalVector((5, 5, 5, 5, 5, 5)) is None
True

>>> chord.fromIntervalVector((1, 1, 1, 1, 1, 1))
<music21.chord.Chord C C# E F#>

>>> chord.fromIntervalVector((1, 1, 1, 1, 1, 1), getZRelation=True)
<music21.chord.Chord C D- E- G>

>>> chord.fromIntervalVector((1, 1, 1, 1, 1, 1)).getZRelation()
<music21.chord.Chord C D- E- G>