20. Voices¶
20.1. Making a voice from a LilyPond input string¶
You can make an Abjad voice from a LilyPond input string:
abjad> voice = Voice("c'8 d'8 e'8 f'8 g'8 a'8 b'4 c''1")
abjad> show(voice)
20.2. Making a voice from a list of other Abjad components¶
You can also make a voice from a list of other Abjad components:
abjad> components = [Tuplet(Fraction(2, 3), "c'4 d'4 e'4"), Note("f'2"), Note("g'1")]
abjad> voice = Voice(components)
abjad> show(voice)
20.3. Understanding the repr of a voice¶
The repr of an Abjad voice contains three parts:
abjad> voice
Voice{3}
Voice tells you the voice’s class.
3 tells you the voice’s length (which is the number of top-level components the voice contains).
Curly braces { and } tell you that the music inside the voice is interpreted sequentially rather than in parallel.
20.4. Inspecting the LilyPond format of a voice¶
Get the LilyPond input format of any Abjad object with format:
abjad> voice.format
"\\new Voice {\n\t\\times 2/3 {\n\t\tc'4\n\t\td'4\n\t\te'4\n\t}\n\tf'2\n\tg'1\n}"
Use f() as a short-cut to print the LilyPond format of any Abjad object:
abjad> f(voice)
\new Voice {
\times 2/3 {
c'4
d'4
e'4
}
f'2
g'1
}
20.5. Inspecting the music in a voice¶
Get voice components with music:
abjad> voice.music
(Tuplet(2/3, [c'4, d'4, e'4]), Note("f'2"), Note("g'1"))
Abjad returns a read-only tuple of components.
20.6. Inspecting a voice’s leaves¶
Get the leaves in a voice with leaves:
abjad> voice.leaves
(Note("c'4"), Note("d'4"), Note("e'4"), Note("f'2"), Note("g'1"))
Abjad returns a read-only tuple of leaves.
20.7. Getting the length of a voice¶
Get voice length with len():
abjad> len(voice)
3
The length of a voice is defined equal to the number of top-level components the voice contains.
20.8. Getting the duration attributes of a voice¶
The contents durations of a voice equals the sum of durations of the components in the voice:
abjad> voice.contents_duration
Duration(2, 1)
The preprolated duration of a voice is usually equal to the voice’s contents duration:
abjad> voice.preprolated_duration
Duration(2, 1)
The prolated duration of a voice is usually equal to the voice’s contents duration, too:
abjad> voice.preprolated_duration
Duration(2, 1)
Only when you nest a very small voice inside a tuplet will the prolated and preprolated duration of a voice differ.
Voices that are not nested inside a tuplet carry a prolation of 1:
abjad> voice.prolation
Fraction(1, 1)
All voice duration attributes are read-only.
20.9. Adding one component to the end of a voice¶
Add one component to the end of a voice with append:
abjad> voice.append(Note("af'2"))
abjad> show(voice)
20.10. Adding many components to the end of a voice¶
Add many components to the end of a voice with extend:
abjad> notes = [Note("g'4"), Note("f'4")]
abjad> voice.extend(notes)
abjad> show(voice)
20.11. Finding the index of a component in a voice¶
Find the index of a component in a voice with index():
abjad> notes[0]
Note("g'4")
abjad> voice.index(notes[0])
4
20.12. Removing a voice component by index¶
Use pop() to remove a voice component by index:
abjad> voice[5]
Note("f'4")
abjad> voice.pop(5)
abjad> show(voice)
20.13. Removing a voice component by reference¶
Remove voice components by reference with remove():
abjad> voice.remove(voice[-1])
abjad> show(voice)
20.14. Naming voices¶
You can name Abjad voices:
abjad> voice.name = 'Upper Voice'
Voice names appear in LilyPond input:
abjad> f(voice)
\context Voice = "Upper Voice" {
\times 2/3 {
c'4
d'4
e'4
}
f'2
g'1
af'2
}
But not in notational output:
abjad> show(voice)
20.15. Changing the context of a voice¶
The context of a voice is set to 'Voice' by default:
abjad> voice.context
'Voice'
But you can change the context of a voice if you want:
abjad> voice.context = 'SpeciallyDefinedVoice'
abjad> voice.context
'SpeciallyDefinedVoice'
abjad> f(voice)
\context SpeciallyDefinedVoice = "Upper Voice" {
\times 2/3 {
c'4
d'4
e'4
}
f'2
g'1
af'2
}
Change the context of a voice when you have defined a new LilyPond context based on a LilyPond voice.