noteforge 0.0.5

A Python library for implementing music theory in data structures, facilitating the management of relationships between notes and the retrieval of specific information about them.

How to use

Note object

The Note object is a core component of this package. A note, such as "A", requires detailed context about its properties to be truly useful, including pitch, position, alteration, octave, and other relevant information. The Note object provides access to this information for user reference or for use by other objects and functions within the package.

import noteforge as nf

note = nf.Note("C#") # => C#3, by default, the octave is 3
note_2 = nf.Note("C#",4) # => C4

The note range is from A0 to C8, based on the standard piano keyboard

note = nf.Note("D",8) # this throws an error

Note name

you can get basic information if needed, the note name consists of three parts: [proper name|alteration|octave], each part can be accessed separately

note = nf.Note("C#") # => C#3, by default, the octave is 3
note_proper_name = note.proper_name # => C
name = note.get_name() # => C#
full_name = note.get_full_name() # => C#3

Note position

Use the provided methods to access positional information. There are three positional values: [natural|chromatic|absolute]

• chromatic : the chromatic index of the note, based on the 12 standard music notes
• natural : the natural index of the note, based on the 7 natural note names that have a proper name C, D, E, F, G, A, B
• absolute : a unique value for each note with the same properties, values range from 9(A0) to 96(C8), so you can use it as a kind of id

import noteforge as nf

note = nf.Note("A",0)

print(note.get_chromatic_position())
print(note.get_natural_position())
print(note.get_absolute_position())   

Another useful properties are:

• alteration contribution : the semitone value of the alteration -- if it is 0 the note not has alteration
• frequency : the fundamental frequency of the note in Hz

print(note.get_freq()) # get frequency of note, in this case : 27.5 Hz
print(note.get_alteration_contribution())

Intervals

musical intervals are represented by two set of strings

• Intervaldegree : a str that represent a valid interval degree, for example [b5,5,#5] has the same degree which 5
• IntervalSymbol : a str that represent a valid interval with quality (minor, major, perfect, etc...) such as [b5,5,#5]

Get interval

This package works with standard intervals. You can use functions to retrieve any of them, but if the interval between notes is non-conventional, it returns None

root = nf.Note("C")
interval_1 = nf.get_interval_between_notes(root,nf.Note("E")) # = 3 as <str> IntervalSymbol
interval_2 = nf.get_interval_between_notes(root,nf.Note("Fb")) # = None because b4 is not and standard interval

interval_3 = nf.get_interval_between_notes(root,nf.Note("Db")) # = b2 as <str> IntervalSymbol
interval_4 = nf.get_interval_between_notes(root,nf.Note("C#")) # = None because #1 or #15 is not and standard interval

Get interval degree

IntervalSymbol can share the same Intervaldegree

interval = nf.get_interval_between_notes(nf.Note("C"), nf.Note("E")) # = 3 as <str> and IntervalSymbol
interval_2 = nf.get_interval_between_notes(nf.Note("C"), nf.Note("Eb")) # = b3 as <str> and IntervalSymbol
degree = nf.get_interval_degree(interval) # = 3 as <str> Intervaldegree
degree_2 = nf.get_interval_degree(interval_2) # = 3 as <str> Intervaldegree

You can get the value of an Intervaldegree. Some Intervaldegrees are extensions of others, so their degree value can be used to relate them.

print(nf.get_interval_degree_value("2")) # = 2
print(nf.get_interval_degree_value("9")) # = 2

Get Note by interval

You can also use interval to get a note_name or directly a Note object — in the latter case, the octave is calculated automatically

root = nf.Note("A",3)
note_name = nf.get_note_name_by_interval(root,"5") # = E as <str>
note = nf.get_note_by_interval(root,"2") # = E4 as <Note>

Transpositions

you can transpose a note by semitones or interval

• Semitone transpose : uses the chromatic scale to transpose without altering the interval degree

note = nf.Note("C", 3)

transposed_note = nf.transpose_note(note, 6)
print(transposed_note.get_full_name()) # F#3

• Interval transpose: This prioritizes the interval's degree, then finds a note or note name matching its semitone distance. Applies to any method using intervals to calculate note distance, like nf.get_note_name_by_interval or nf.get_note_by_interval

note = nf.Note("C",3)

transposed_note_2 = nf.get_note_by_interval(note, "#4")
print(transposed_note_2.get_full_name()) # = F#3
transposed_note_3 = nf.get_note_by_interval(note, "b5")
print(transposed_note_3.get_full_name()) # = Gb3

• Interval degree transposition: try transform the interval degree while maintaining the interval quality, throw None if the result don't exist in standard intervals

interval = "b3"
transposed = nf.transpose_interval_degree(interval,"9") # = b9 as <str> IntervalSymbol
transposed_2 = nf.transpose_interval_degree(interval,"4") # = None, because 'b4' is not an standard interval