Transposition

class pitchtools.Transposition(n=0)

Transposition operator.

>>> import abjad
>>> import pytest
>>> abjad.Transposition()
Transposition(n=0)
>>> abjad.Transposition(n=2)
Transposition(n=2)

Object model of twelve-tone transposition operator.

Lineage

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Bases

Attribute summary

n Gets index of transposition.
__add__(operator) Composes transposition and operator.
__call__(argument) Calls transposition on argument.
__copy__(*arguments) Copies Abjad value object.
__eq__(argument) Is true when all initialization values of Abjad value object equal the initialization values of argument.
__format__([format_specification]) Formats Abjad object.
__hash__() Hashes Abjad value object.
__ne__(argument) Is true when Abjad object does not equal argument.
__radd__(operator) Right-addition not defined on transposition.
__repr__() Gets interpreter representation of Abjad object.
__str__() Gets string representation of operator.

Read-only properties

Transposition.n

Gets index of transposition.

>>> transposition = abjad.Transposition()
>>> transposition.n
0
>>> transposition = abjad.Transposition(n=2)
>>> transposition.n
2

Set to integer, interval or none.

Special methods

Transposition.__add__(operator)

Composes transposition and operator.

Example segment:

>>> items = [0, 2, 4, 5]
>>> segment = abjad.PitchClassSegment(items=items)
>>> show(segment) 

Example operators:

>>> T_1 = abjad.Transposition(n=1)
>>> T_3 = abjad.Transposition(n=3)

Successive transposition:

>>> operator = T_1 + T_3
>>> str(operator)
'T1T3'
>>> segment_ = operator(segment)
>>> show(segment_) 

Same as above because transposition commutes:

>>> operator = T_3 + T_1
>>> str(operator)
'T3T1'
>>> segment_ = operator(segment)
>>> show(segment_) 

Returns compound operator.

Transposition.__call__(argument)

Calls transposition on argument.

Transposes pitch-class:

>>> transposition = abjad.Transposition(n=2)
>>> pitch_class = abjad.NumberedPitchClass(1)
>>> transposition(pitch_class)
NumberedPitchClass(3)

Transposes pitch:

>>> transposition = abjad.Transposition(n=2)
>>> pitch = abjad.NumberedPitch(15)
>>> transposition(pitch)
NumberedPitch(17)

Transposes list of pitches:

>>> transposition = abjad.Transposition(n=2)
>>> pitches = [abjad.NumberedPitch(_) for _ in [15, 16]]
>>> transposition(pitches)
[NumberedPitch(17), NumberedPitch(18)]

Returns new object with type equal to that of argument.

(AbjadValueObject).__copy__(*arguments)

Copies Abjad value object.

Returns new Abjad value object.

(AbjadValueObject).__eq__(argument)

Is true when all initialization values of Abjad value object equal the initialization values of argument.

Returns true or false.

(AbjadObject).__format__(format_specification='')

Formats Abjad object.

Set format_specification to ‘’ or ‘storage’. Interprets ‘’ equal to ‘storage’.

Returns string.

(AbjadValueObject).__hash__()

Hashes Abjad value object.

Returns integer.

(AbjadObject).__ne__(argument)

Is true when Abjad object does not equal argument. Otherwise false.

Returns true or false.

Transposition.__radd__(operator)

Right-addition not defined on transposition.

>>> string = 'abjad.Transposition().__radd__(abjad.Transposition())'
>>> pytest.raises(NotImplementedError, string)
<ExceptionInfo NotImplementedError tblen=3>

Raises not implemented error.

(AbjadObject).__repr__()

Gets interpreter representation of Abjad object.

Returns string.

Transposition.__str__()

Gets string representation of operator.

>>> str(abjad.Transposition())
'T0'
>>> str(abjad.Transposition(n=2))
'T2'