3. Chords

3.1. Making chords from a LilyPond input string

You can make chords from a LilyPond input string:

abjad> chord = Chord("<c' d' bf'>4")

abjad> show(chord)

3.2. Making chords from chromatic pitch numbers and duration

You can also make chords from chromatic pitch numbers and duration:

abjad> chord = Chord([0, 2, 10], Duration(1, 4))

abjad> show(chord)

3.3. Getting all the written pitches of a chord at once

You can get all the written pitches of a chord at one time:

abjad> chord.written_pitches
(NamedChromaticPitch("c'"), NamedChromaticPitch("d'"), NamedChromaticPitch("bf'"))

Abjad returns a read-only tuple of named chromatic pitches.

3.4. Getting the written pitches of a chord one at a time

You can get the written pitches of a chord one at a time:

abjad> chord.written_pitches[0]
NamedChromaticPitch("c'")

Chords index the pitch they contain starting from 0 (just like tuples and lists).

3.5. Adding one pitch to a chord at a time

Use append() to add one note to a chord.

You can add a pitch to a chord with a chromatic pitch number:

abjad> chord.append(9)

abjad> show(chord)

Or you can add a pitch to a chord with a chromatic pitch name:

abjad> chord.append("df''")

abjad> show(chord)

Chords sort their pitches every time you add a new one.

This means you can add pitches to your chord in any order.

3.6. Adding many pitches to a chord at once

Use extend() to add many pitches to a chord.

You can use chromatic pitch numbers:

abjad> chord.extend([3, 4, 14])

abjad> show(chord)

Or you can chromatic pitch names:

abjad> chord.extend(["g''", "af''"])

abjad> show(chord)

3.7. Deleting pitches from a chord

Delete pitches from a chord with del():

abjad> del(chord[0])

abjad> show(chord)

abjad> del(chord[0])

abjad> show(chord)

Negative indices work too:

abjad> del(chord[-1])

abjad> show(chord)

3.8. Formatting chords

Get the LilyPond input format of any Abjad object with format:

abjad> chord.format
<ef' e' a' bf' df'' d'' g''>4

Use f() as a short-cut to print the LilyPond input format of any Abjad object:

abjad> f(chord)
<ef' e' a' bf' df'' d'' g''>4

3.9. Working with note heads

Most of the time you will work with the pitches of a chord. But you can get the note heads of a chord, too:

abjad> chord.note_heads
(NoteHead("ef'"), NoteHead("e'"), NoteHead("a'"), NoteHead("bf'"), NoteHead("df''"), NoteHead("d''"), NoteHead("g''"))

This is useful when you want to apply LilyPond overrides to note heads in a chord one at a time:

abjad> chord[2].tweak.color = 'red'
abjad> chord[3].tweak.color = 'blue'
abjad> chord[4].tweak.color = 'green'

abjad> f(chord)
<
        ef'
        e'
        \tweak #'color #red
        a'
        \tweak #'color #blue
        bf'
        \tweak #'color #green
        df''
        d''
        g''
>4

abjad> show(chord)

3.10. Working with empty chords

Abjad allows empty chords:

abjad> chord = Chord([], Duration(1, 4))
Chord('<>4')

Abjad formats empty chords, too:

abjad> f(chord)
<>4

But if you pass empty chords to show() LilyPond will complain because empty chords don’t constitute valid LilyPond input.

When you are done working with an empty chord you can add pitches back into it chord in any of the ways described above:

abjad> chord.extend(["gf'", "df''", "g''"])

abjad> show(chord)