### Install Sphinx with pip

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/developerReference/buildingDocumentation.rst

Install the Sphinx documentation generator. Use 'sudo pip3 install sphinx' on Mac and 'pip3 install sphinx' on Windows.

```bash
sudo pip3 install sphinx
```

```bash
pip3 install sphinx
```

--------------------------------

### Import music21 in Python

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/installing/installMac.rst

After starting the Python interpreter, type this to verify that music21 has been installed correctly. This should not produce any errors.

```python
import music21
```

--------------------------------

### Install Jupyter and IPython

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/developerReference/installJupyter.ipynb

Install the necessary Jupyter and IPython packages using pip. Ensure you have a working pip installation of music21 first.

```bash
sudo pip install jupyter
$ sudo pip install ipython
```

--------------------------------

### Display Key Signature Example (13a)

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/developerReference/musicxmlTest.ipynb

Displays a standard key signature example. This is useful for visualizing common key signatures.

```python
s('13a')
```

--------------------------------

### Get Verticality at Offset (Start Example)

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/usersGuide/usersGuide_61_trees.ipynb

Demonstrates creating a Verticality object at offset 0, which can include non-pitched elements like text boxes and metadata.

```python
v_start = tsTree.getVerticalityAt(0)
```

```python
v_start
```

--------------------------------

### Install Sphinx for Documentation

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/developerReference/documenting.rst

Install Sphinx, a documentation generator, using pip3. This is necessary for building documentation from .rst files.

```bash
pip3 install sphinx
```

--------------------------------

### Installing Dependencies with uv sync

Source: https://github.com/cuthbertlab/music21/blob/master/AGENTS.md

Command to install runtime dependencies and the development group, which includes optional extras like scipy and python-Levenshtein, essential for tests.

```bash
uv sync
```

--------------------------------

### Create and Show Example Score

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/testsAndInProgress/devTest_timespans.ipynb

Generates an example score using music21's tree module and displays it visually.

```python
score = tree.makeExampleScore()
score.show()
```

--------------------------------

### Install music21 using pip

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/installing/installWindows.rst

Use this command to download and install the music21 library. This is the standard method for installing Python packages.

```bash
pip install music21
```

--------------------------------

### Parse and Display Bach Example

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/usersGuide/usersGuide_08_installingMusicXML.ipynb

Loads a Bach piece from the music21 corpus, selects the first six measures, and displays it. Ensure music21 is installed with its corpus module.

```python
b = corpus.parse('bach/bwv66.6')
b = b.measures(0, 5) #_DOCS_HIDE
b.show() # I've altered this so it's much shorter than it should be...

```

--------------------------------

### Cross-Staff Beaming (Failing Example)

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/developerReference/musicxmlTest.ipynb

This example is intended to demonstrate cross-staff beaming but is noted as failing in music21.

```python
s('43d') # failing # cross-staff-beaming. fails utterly in m21 so far.
```

--------------------------------

### Install anywidget Package

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/testsAndInProgress/devTest_widgets.ipynb

Installs the 'anywidget' package using pip. This is a prerequisite for creating custom Jupyter widgets, as it's not part of the standard music21 ecosystem.

```python
%pip install anywidget
```

--------------------------------

### Run Jupyter Notebook

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/developerReference/documenting.rst

Navigate to the desired directory and run this command to start a Jupyter Notebook server.

```bash
jupyter notebook
```

--------------------------------

### Install Jupyter Notebook

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/developerReference/documenting.rst

Install Jupyter Notebook using pip3. This is required for editing .ipynb documentation files.

```bash
pip3 install jupyter
```

--------------------------------

### Configure music21

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/installing/installLinux.rst

Run this command to configure music21 after installation. You will be prompted to provide the path to your MusicXML reader.

```bash
python3 -m music21.configure
```

--------------------------------

### Setting Explicit Start and Stop Ties

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/usersGuide/usersGuide_31_clefs.ipynb

Illustrates the importance of explicitly setting both 'start' and 'stop' ties when required by analysis programs, although music21 often infers the stop tie from the start tie.

```python
c1 = chord.Chord('C#4 E4 G4')
c2 = chord.Chord('C4 E4 G4')
c1[1].tie = tie.Tie('start')
c2[1].tie = tie.Tie('stop')
c1[2].tie = tie.Tie('start')
c2[2].tie = tie.Tie('stop')
s = stream.Stream()
s.append([c1, c2])
s.show()
```

--------------------------------

### Display Three-Note Chords with Durations Example (21c)

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/developerReference/musicxmlTest.ipynb

Presents three-note chords with varying durations. This example is useful for testing how different note lengths within chords are handled.

```python
s('21c')
```

--------------------------------

### Display Basic Chord Example (21a)

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/developerReference/musicxmlTest.ipynb

Shows a simple chord consisting of two notes. This is a fundamental example for chord representation.

```python
s('21a')
```

--------------------------------

### Install nbconvert with pip

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/developerReference/buildingDocumentation.rst

Use this command to install the nbconvert package, which is needed for converting Jupyter notebooks to documentation format. Omit 'sudo' on Windows.

```bash
sudo pip3 install nbconvert
```

--------------------------------

### Install PyAudio on Mac

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/installing/installAdditional.rst

Use these commands to install PyAudio on a Mac. PyAudio allows for recording within Python and is used for the audioSearch module. It requires portaudio and Xcode command-line development tools.

```bash
xcode-select --install
brew install portaudio
pip3 install pyaudio
```

--------------------------------

### Display Key Signature Cancellation Example (13ab)

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/developerReference/musicxmlTest.ipynb

Tests key signature cancellation. Note: This example is not supported by MuseScore.

```python
s('13ab') # no music21 support; blocked MuseScore
```

--------------------------------

### Module-Level Documentation String

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/developerReference/documenting.rst

Example of a module-level documentation string. This should be placed at the top of a Python module before import statements.

```python
'''
    I am documentation for this module!
    '''
```

--------------------------------

### Install or Upgrade music21

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/installing/installLinux.rst

Use pip to download and install or upgrade to the latest version of music21. This command should be run in your terminal.

```bash
pip3 install --upgrade music21
```

--------------------------------

### Create Notes with Start, Continue, and Stop Ties

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/usersGuide/usersGuide_31_clefs.ipynb

Manually creates three C4 notes with 'start', 'continue', and 'stop' tie types, appends them to a measure, and displays the result. This demonstrates the 'continue' tie type.

```python
c0 = note.Note('C4')
c0.tie = tie.Tie('start')
c1 = note.Note('C4')
c1.tie = tie.Tie('continue')
c2 = note.Note('C4')
c2.tie = tie.Tie('stop')
s = stream.Measure()
s.append([c0, c1, c2])
s.show()
```

--------------------------------

### Simple Piano Staff

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/developerReference/musicxmlTest.ipynb

A basic example of creating a piano staff in MusicXML using music21.

```python
s('43a')
```

--------------------------------

### Run the music21 documentation build script

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/developerReference/buildingDocumentation.rst

Navigate to the documentation directory within the music21 installation and run this script to build the documentation. It will automatically open your web browser.

```bash
python3 make.py
```

--------------------------------

### Recursive Harmonic Analysis Example

Source: https://github.com/cuthbertlab/music21/blob/master/music21/romanText/clercqTemperley_format.html

Demonstrates a recursive notation for harmonic analysis, where sections are defined by symbols that can be reused in higher-level expressions. The example shows a song structure with verses, choruses, and a key.

```text
VP: I IV |
Vr: $VP $VP I ii | V |
Ch: I V | vi IV |
S: [C] $Vr $Ch $Vr $Ch $Ch I |
```

--------------------------------

### Get Start Timespans at Time 22.0

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/testsAndInProgress/devTest_timespans.ipynb

Retrieves and displays timespans that start at offset 22.0 for the verticality at 22.0.

```python
v22.startTimespans
```

--------------------------------

### Tied Notes in MusicXML

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/developerReference/musicxmlTest.ipynb

Illustrates two simple tied whole notes. This example focuses on the basic implementation of ties.

```python
s('33b') # not necessarily a spanner except in Lilypond
```

--------------------------------

### Generate Notehead Styles in Chords (MuseScore)

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/developerReference/musicxmlTest.ipynb

Use the s('22c') command to generate examples of different notehead styles within chords. This tests the <notehead> element for individual notes in a chord. Note that this specific example is blocked by MuseScore.

```python
s('22c') # blocked by MuseScore: 22a
```

--------------------------------

### Configure music21 from IDLE

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/installing/installWindows.rst

Import music21 in IDLE and then call the run() function to initiate the configuration process for helper programs.

```python
import music21
music21.configure.run()
```

--------------------------------

### Get Start Timespans at Time 3.5

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/testsAndInProgress/devTest_timespans.ipynb

Retrieves and displays timespans that start at offset 3.5 for the specified verticality.

```python
v35.startTimespans
```

--------------------------------

### Initialize Analysis Tool and Results Storage

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/testsAndInProgress/devTest_unconvertedExamples.ipynb

Sets up an analysis tool for melodic interval diversity and prepares a list to store the results of corpus searches.

```python
# Get an analysis tool
diversityTool = analysis.discrete.MelodicIntervalDiversity()

# get a list to store results.
results = []
```

--------------------------------

### Get Elements Starting at Offset

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/usersGuide/usersGuide_61_trees.ipynb

Retrieve all timespans that begin at a specific offset in the timespan tree. This is useful for finding all musical events that start at a precise moment.

```python
tsTree.elementsStartingAt(7.0)
```

--------------------------------

### Initialize note articulations list

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/usersGuide/usersGuide_32_articulations.ipynb

Demonstrates how to check the articulations list of a note, which is initially empty.

```Python
n1 = note.Note('A4')
n1.articulations
```

--------------------------------

### Get a Measure Stack Across All Parts

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/usersGuide/usersGuide_06_stream2.ipynb

The `.measures(start, end)` method can be called on a whole score to get a 'measureStack', which is a collection of measures across all parts for the specified measure numbers.

```python
measureStack = sBach.measures(2, 3)
measureStack.show()
```

--------------------------------

### Get the Tie Type as a String

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/usersGuide/usersGuide_31_clefs.ipynb

Retrieves the type of the tie ('start' or 'stop') as a string from the `.type` attribute of a Tie object.

```python
n1.tie.type
```

```python
n1.next('Note').tie.type
```

--------------------------------

### Display Extreme Key Signature Example (13aa)

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/developerReference/musicxmlTest.ipynb

Displays extreme key signature examples, including those with many flats or sharps. Note: MuseScore and Finale may have issues with flats.

```python
s('13aa') # blocked: MuseScore and Finale (on flats; sharps import fine)
```

--------------------------------

### Install SciPy on Mac (python.org)

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/installing/installAdditional.rst

Use this command to install SciPy if you are using the Python version from python.org on a Mac. SciPy provides scientific extensions to Python and is used for accelerating audio searching and fast-Fourier transforms.

```bash
pip3 install scipy
```

--------------------------------

### Get Generic Interval Size

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/usersGuide/usersGuide_20_examples2.ipynb

Retrieves the generic size of an interval, ignoring its direction. For example, both a major second and a minor second have a generic interval of 2.

```python
firstInterval.generic
```

--------------------------------

### Create UserSettings Configuration File

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/usersGuide/usersGuide_24_environment.ipynb

Import environment and create a UserSettings object, then call create() to generate an XML environment file. This file stores persistent settings.

```python
from music21 import *
us = environment.UserSettings()
#_DOCS_SHOW us.create()
```

--------------------------------

### Create and Append a Start Beam

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/usersGuide/usersGuide_31_clefs.ipynb

Manually creates a Beam object with the type 'start' and number '1', then appends it to the Beams object of a note. This is useful for explicitly defining the beginning of a beam group.

```python
beam1 = beam.Beam(type='start', number=1)
```

```python
d1Beams = d1.beams
d1Beams.append(beam1)
d1.beams
```

--------------------------------

### Get spanners attached to an element

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/usersGuide/usersGuide_29_spanners.ipynb

Query an element to see all spanners it belongs to using `.getSpannerSites()`. An element can be part of multiple spanners, as demonstrated by the example output.

```python
g.getSpannerSites()
```

--------------------------------

### Playing a Note via MIDI

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/usersGuide/usersGuide_02_notes.ipynb

Use the .show('midi') method to play a Note object as MIDI. This requires specific OS and QuickTime versions on some platforms.

```python
f.show('midi')
```

--------------------------------

### Generic Class Example

Source: https://github.com/cuthbertlab/music21/blob/master/CLAUDE.md

Illustrates the bracket syntax for generic classes in Python 3.12+.

```python
class Stream[M21ObjType: base.Music21Object]:
```

--------------------------------

### Initialize TinyNotation Converter

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/usersGuide/usersGuide_16_tinyNotation.ipynb

Instantiate the TinyNotation Converter with a music string to parse.

```python
tnc = tinyNotation.Converter('6/8 e4. d8 c# d e2.')
```

--------------------------------

### Get Verticality at Offset

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/usersGuide/usersGuide_61_trees.ipynb

Create a Verticality object representing the musical state at a specific offset. This object aggregates elements that start, overlap, or stop at that exact moment.

```python
v = tsTree.getVerticalityAt(8.0)
```

```python
v
```

--------------------------------

### Fetch Latest Commits

Source: https://github.com/cuthbertlab/music21/blob/master/CLAUDE.md

Command to run at the start of every session to ensure work begins from the latest commits.

```bash
git fetch
```

--------------------------------

### Get a Range of Measures from a Part

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/usersGuide/usersGuide_06_stream2.ipynb

Use the `.measures(start, end)` method on a part to extract a Stream containing measures within the specified range. The part is accessed by its index.

```python
alto = sBach.parts[1]  # parts count from zero, so soprano is 0 and alto is 1
excerpt = alto.measures(1, 4)
excerpt.show()
```

--------------------------------

### Class Inheritance Example

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/usersGuide/usersGuide_06_stream2.ipynb

Demonstrates basic class inheritance in Python, showing how a subclass can access attributes from its parent class.

```python
class Japan:
    food = 'sushi'
    drink = 'sake'

class Okinawa(Japan):
    evenBetterFood = 'spam potstickers'
```

--------------------------------

### Generate Transposing Instruments Example

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/developerReference/musicxmlTest.ipynb

Generates a MusicXML file demonstrating transposing instruments like Trumpet in Bb and Horn in Eb. Shows how different instruments display the same scale.

```python
s('72a')
```

--------------------------------

### Get All Time Points

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/usersGuide/usersGuide_61_trees.ipynb

Retrieve a sorted tuple of all unique time points where any element in the timespan tree either starts or stops. This provides a comprehensive overview of all significant temporal events.

```python
tsTree.allTimePoints()[:13]
```

--------------------------------

### Get music21 source file path

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/developerReference/buildingDocumentation.rst

If you cannot locate your music21 installation, use these Python commands to import music21 and find the source file path. The documentation directory is typically located above this path.

```python
from music21 import *
common.getSourceFilePath()
```

--------------------------------

### Get MeterSequence Level Span

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/usersGuide/usersGuide_55_advancedMeter.ipynb

The `getLevelSpan` method returns the time span of each node at a given depth as a list of start and end values. This helps in understanding the temporal extent of meter components at a specific level.

```python
ms.getLevelSpan(1)
```

```python
ms[1].getLevelSpan(1)
```

--------------------------------

### Configure music21 from Command Prompt

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/installing/installWindows.rst

Execute this command in the command prompt to configure music21 and set up paths for helper programs like MuseScore or Finale.

```bash
python3 -m music21.configure
```

--------------------------------

### Get the first and last elements of a spanner

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/usersGuide/usersGuide_29_spanners.ipynb

Retrieve the first and last elements contained within a spanner using the `.getFirst()` and `.getLast()` methods. This helps in identifying the start and end points of a spanned musical phrase.

```python
sl2.getFirst()
```

```python
sl2.getLast()
```

--------------------------------

### Display Mid-Measure Key Change Example (13e)

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/developerReference/musicxmlTest.ipynb

Demonstrates key changes occurring within a measure, showing transitions between different key signatures.

```python
s('13e')
```

--------------------------------

### Refined Regular Expression Search

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/usersGuide/usersGuide_11_corpusSearching.ipynb

Employ a more specific regular expression to match terms at the beginning of a word, improving search accuracy. This example refines the previous search to only match names starting with 'ha' followed by any character and then 'd'.

```python
import re
haydnOrHandel = re.compile(r'^ha.d.*', re.IGNORECASE)
```

--------------------------------

### Search Metadata Using a Compiled Regular Expression

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/usersGuide/usersGuide_11_corpusSearching.ipynb

Use compiled regular expressions to search metadata fields. This example demonstrates searching for names starting with 'ha' followed by any character and then 'd', case-insensitively. Be aware that broad patterns may yield unexpected results.

```python
import re
haydnOrHandel = re.compile(r'ha.d.*', re.IGNORECASE)
corpus.corpora.CoreCorpus().search(haydnOrHandel)
```

--------------------------------

### Run Configuration Tool

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/usersGuide/usersGuide_08_installingMusicXML.ipynb

Executes the music21 configuration tool to detect and set up external music notation software like MuseScore, Finale, or Sibelius. Respond 'no' to prompts unless you need to specify a custom path.

```python
#_DOCS_SHOW configure.run()

```

--------------------------------

### Instantiating and Running a Plot Class

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/usersGuide/usersGuide_44_advancedGraphing.ipynb

Demonstrates how to create an instance of a specific plot class (ScatterPitchClassOffset) and then execute its run() method to generate the plot.

```python
scatter = graph.plot.ScatterPitchClassOffset(bach)
scatter
```

```python
scatter.run()
```

--------------------------------

### Displaying a Note as MusicXML

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/usersGuide/usersGuide_02_notes.ipynb

Use the .show() method to display a Note object. By default, it renders as a MusicXML image if a reader is installed.

```python
f.show()
```

--------------------------------

### Access Start Timespans

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/testsAndInProgress/devTest_timespans.ipynb

Retrieves and displays the timespans that start at the beginning of the selected verticality.

```python
v4.startTimespans
```

--------------------------------

### Convert Example Score to Timespans

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/testsAndInProgress/devTest_timespans.ipynb

Converts the generated example score into a Timespan collection for analysis.

```python
tsColSmall = score.asTimespans()
```

--------------------------------

### Run Test Case '01a'

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/developerReference/musicxmlTest.ipynb

Executes the test case '01a' which focuses on pitches and accidentals. This involves parsing a MusicXML file and displaying the result, likely for visual verification.

```python
s('01a')
```

--------------------------------

### Install music21 on macOS Sierra or El Capitan

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/installing/installMac.rst

Use this command in the Terminal to install music21. You will be prompted for your password.

```bash
sudo pip3 install music21
```

--------------------------------

### Display Chord Visualization

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/usersGuide/usersGuide_07_chords.ipynb

Use the `.show()` method to display a visual representation of the chord. This requires additional setup and may not work in all environments.

```python
cMinor.show()
```

```python
cMajor.show()
```

--------------------------------

### Generate Full Transposing Instruments Example

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/developerReference/musicxmlTest.ipynb

Generates a MusicXML file with various transpositions, showing different display pitches for the same concert pitch. Includes untransposed instruments.

```python
s('72b')
```

--------------------------------

### Access Element from Start Timespan

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/testsAndInProgress/devTest_timespans.ipynb

Extracts a specific start timespan and its associated musical element from the verticality at 3.5.

```python
elTsC = v35.startTimespans[0]
print(elTsC, elTsC.element)
```

--------------------------------

### Run Documentation Tests

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/developerReference/testing.ipynb

Execute this command in the documentation directory to test documentation changes. Ensure you are using Python 3.

```bash
testDocumentation.py
```

--------------------------------

### Handle Too Many Parts

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/developerReference/musicxmlTest.ipynb

This example addresses a scenario where a MusicXML file contains more part elements than are listed in the part-list. The library can either convert all available parts or ignore the unlisted ones. The snippet is noted as producing warnings.

```python
s('41h') # warns, skips the part -- acceptable behavior
```

--------------------------------

### Create and Display a Note

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/about/what.ipynb

Create a musical note with a specific pitch and duration, then display it visually. This demonstrates basic note object creation and manipulation.

```python
n = note.Note('D#3')
n.duration.type = 'half'
n.show()

```

--------------------------------

### Display Church Modes Key Signature Example (13b)

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/developerReference/musicxmlTest.ipynb

Displays key signatures for all church modes (major, minor, ionian, dorian, phrygian, lydian, mixolydian, aeolian, locrian) with two sharps.

```python
s('13b')
```

--------------------------------

### Setting Key and Transposing Notes

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/usersGuide/usersGuide_15_key.ipynb

Creates a stream with D major and B-flat minor keys, appends F-natural whole notes, and then transposes the notes up a half step to observe spelling changes.

```python
s = stream.Stream()
s.append(key.Key('D'))
s.append(note.Note('F', type='whole'))
s.append(key.Key('b-', 'minor'))
s.append(note.Note('F', type='whole'))
s2 = s.makeNotation()
s2.show()
```

```python
for n in s2.recurse().notes:
    n.transpose(1, inPlace=True)
s2.show()
```

--------------------------------

### Get Roman Numeral Figure and Key

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/usersGuide/usersGuide_23_romanNumerals.ipynb

Accesses the `figureAndKey` property of a RomanNumeral object to get a combined string representation of the numeral and its key.

```python
rf.figureAndKey
```

--------------------------------

### Show MIDI Output

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/testsAndInProgress/notebook_show_tests.ipynb

Displays a piece in MIDI format using the .show('midi') method. This is useful for interactive playback or embedding MIDI within a notebook.

```python
c.show('midi')

```

--------------------------------

### Load music21 and IPython Extension

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/testsAndInProgress/devTest_unconvertedExamples.ipynb

Initial setup for using music21 within an IPython environment. This code is typically run once at the beginning of a session.

```python
# ignore this
%load_ext music21.ipython21
from music21 import *
```

--------------------------------

### Import Chords as Grace Notes

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/developerReference/musicxmlTest.ipynb

Imports MusicXML where chords are represented as grace notes.

```python
s('24b')
```

--------------------------------

### Add Music Files to New Metadata Bundle

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/usersGuide/usersGuide_53_advancedCorpus.ipynb

Creates a new metadata bundle and adds music files from specified paths. Returns a list of paths that failed to be added.

```python
newBundle = metadata.bundles.MetadataBundle()
paths = corpus.corpora.CoreCorpus().search('corelli')
failedPaths = newBundle.addFromPaths(paths)
failedPaths
```

--------------------------------

### Inspect Start and End Notes of an Interval

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/usersGuide/usersGuide_20_examples2.ipynb

Retrieves the starting and ending 'Note' objects of a specific 'Interval' object. This helps in understanding the melodic context of the interval.

```python
firstInterval = allIntervals[0]
firstInterval.noteStart
```

```python
firstInterval.noteEnd
```

--------------------------------

### Get Memory Address of an Object

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/usersGuide/usersGuide_12_music21object.ipynb

Uses the built-in Python `id()` function to get the memory address of a music21 object, which is the default value for the `.id` attribute.

```python
id(n)
```

--------------------------------

### Show Stream (Implicitly Makes Ties)

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/usersGuide/usersGuide_31_clefs.ipynb

Displays a stream. The `show()` method implicitly calls `makeTies` to ensure the music can be displayed correctly in MusicXML, even if ties were previously stripped.

```python
littleStripped.show()
```

--------------------------------

### Get Elements by Offset in Music21

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/usersGuide/usersGuide_04_stream1.ipynb

Use getElementsByOffset() to retrieve elements at a specific offset or within a range. Add .stream() to get a Stream object from the result.

```python
sOut = stream1.getElementsByOffset(3)
len(sOut)
```

```python
sOut[0]
```

```python
sOut = stream1.getElementsByOffset(2, 3).stream()
sOut.show('text')
```

--------------------------------

### Import Tremolo Tuplets

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/developerReference/musicxmlTest.ipynb

Imports tremolo tuplets from MusicXML. Ensure the application supports tuplet duration scaling.

```python
s('23e')
```

--------------------------------

### Enable music21 Notebook Extension

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/developerReference/installJupyter.ipynb

Enable the 'usability/sphinx-markdown/main' notebook extension. This command initiates the enabling process and may show validation issues.

```python
E = notebook.nbextensions.EnableNBExtensionApp()
E.toggle_nbextension('usability/sphinx-markdown/main')
```

--------------------------------

### Install Matplotlib on Mac (python.org)

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/installing/installAdditional.rst

Use this command to install Matplotlib if you are using the Python version from python.org on a Mac. Matplotlib is used for graphing and visual displays in music21.

```bash
pip3 install matplotlib
```

--------------------------------

### Verticality Start Timespans (Non-Pitched)

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/usersGuide/usersGuide_61_trees.ipynb

Display the start timespans for a Verticality at offset 0, which may include non-pitched elements such as text boxes, metadata, and layout information.

```python
v_start.startTimespans[:10]
```

--------------------------------

### Create specific articulation objects

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/usersGuide/usersGuide_32_articulations.ipynb

Shows how to create instances of specific articulation classes like Staccato and Accent.

```Python
stac = articulations.Staccato()
acc = articulations.Accent()
```

--------------------------------

### Install Pygame on Mac

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/installing/installAdditional.rst

Use this command to install Pygame on a Mac. Pygame allows for real-time MIDI performance and is used in the midi.realtime module. Pygame 1.9 or later is required.

```bash
pip3 install pygame
```

--------------------------------

### Create a basic Articulation object

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/usersGuide/usersGuide_32_articulations.ipynb

Demonstrates how to create a generic Articulation object. This is the base class for all articulations.

```Python
from music21 import *

art = articulations.Articulation()
art
```

--------------------------------

### Get Offset by Site in Music21

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/usersGuide/usersGuide_04_stream1.ipynb

Use getOffsetBySite() for a more robust way to get an element's offset within a specific Stream, especially when an element might be in multiple Streams.

```python
note2.offset
```

```python
note2.getOffsetBySite(stream1)
```

--------------------------------

### Create and Configure a New Local Corpus in Python

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/usersGuide/usersGuide_53_advancedCorpus.ipynb

Creates a new named local corpus, assigns a directory for music files, and saves its settings. This allows for persistent, custom corpus management across sessions.

```python
from music21 import *

aNewLocalCorpus = corpus.corpora.LocalCorpus('newCorpus')
aNewLocalCorpus.existsInSettings
```

```python
aNewLocalCorpus.addPath('~/Desktop')
#_DOCS_SHOW aNewLocalCorpus.directoryPaths
print("('/Users/j_wolf/Desktop',)") #_DOCS_HIDE
```

```python
aNewLocalCorpus.save()
aNewLocalCorpus.existsInSettings
```

--------------------------------

### Install NumPy on Mac (python.org)

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/installing/installAdditional.rst

Use this command to install NumPy if you are using the Python 3 version from python.org on a Mac. NumPy provides numeric extensions to Python and is included with Matplotlib.

```bash
pip3 install numpy
```

--------------------------------

### List Available UserSettings Keys

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/usersGuide/usersGuide_24_environment.ipynb

Iterate through the keys of a UserSettings object to see all configurable environment settings. This helps in understanding what can be customized.

```python
for key in sorted(us.keys()):
    print(key)
```

--------------------------------

### Display Chord Example in Context (21d)

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/developerReference/musicxmlTest.ipynb

Shows chords appearing in the second measure, following ornaments and dynamics in the first measure. This tests chord detection in a more complex musical context.

```python
s('21d') # Chords in the second measure, after several ornaments in the first measure and a p at the beginning of the second measure.
```

--------------------------------

### Install Matplotlib on Mac (Anaconda)

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/installing/installAdditional.rst

Use these commands to install Matplotlib if you are using a version of Python from Anaconda (conda, miniconda, etc.) on a Mac. Matplotlib is used for graphing and visual displays in music21.

```bash
conda install matplotlib
conda install python.app
```

--------------------------------

### Creating a Note Object

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/usersGuide/usersGuide_02_notes.ipynb

Demonstrates the correct way to create a Note object using the music21 library. Avoid using 'note' as a variable name to prevent conflicts with the 'note' module.

```python
note = note.Note("C#3")
```

--------------------------------

### Generate MusicXML for Voice 2 Starting Later

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/developerReference/musicxmlTest.ipynb

Generates a MusicXML file where the second voice is intended to start on the second beat of the first full measure. This tests synchronization of multiple voices.

```python
s('46e')
```

--------------------------------

### Configure StrongAccent direction and placement

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/usersGuide/usersGuide_32_articulations.ipynb

Demonstrates setting the pointDirection and placement for a StrongAccent articulation.

```Python
sacc = articulations.StrongAccent()
sacc.pointDirection
sacc.placement = 'above'
```

--------------------------------

### Create and Populate a Stream

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/usersGuide/usersGuide_04_stream1.ipynb

Create a new Stream, add a Note to it at offset 0, and then append another Stream to it.

```python
biggerStream = stream.Stream()
note2 = note.Note('D#5')
biggerStream.insert(0, note2)
biggerStream.append(stream1)
```

--------------------------------

### Invalid Variable Name Example

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/usersGuide/usersGuide_02_notes.ipynb

This example demonstrates an invalid attempt to name a variable 'b-flat' using a hyphen. Python syntax does not allow hyphens in variable names, leading to a SyntaxError. Use underscores or camelCase instead.

```python
b-flat = note.Note("B-2")
```

--------------------------------

### Chord List Output Example

Source: https://github.com/cuthbertlab/music21/blob/master/music21/romanText/clercqTemperley_format.html

Presents the 'chord list' format for harmonic analysis, showing chords on a timeline defined by measures. This format is generated by the expander program and includes timing information.

```text
0.00  0.50   I    0   1   0   0
0.50  1.00   IV   5   4   0   5
1.00  1.50   I    0   1   0   0
1.50  2.00   IV   5   4   0   5
(etc.)
```

--------------------------------

### Get altered pitches

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/usersGuide/usersGuide_15_key.ipynb

Retrieve a list of pitches that are altered by the key signature.

```python
ks2.alteredPitches
```

--------------------------------

### Get Undirected Interval Value

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/usersGuide/usersGuide_20_examples2.ipynb

Retrieves the undirected generic value of an interval.

```python
secondInterval.generic.undirected
```

--------------------------------

### Create and append Notes, Rests, and Chords to a Stream

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/usersGuide/usersGuide_07_chords.ipynb

Demonstrates creating a Rest and a Note, setting their durations, and appending them along with a pre-defined Chord to a Stream. Use this to build simple musical sequences.

```python
rest1 = note.Rest()
rest1.quarterLength = 0.5
noteASharp = note.Note('A#5')
noteASharp.quarterLength = 1.5

stream2 = stream.Stream()
stream2.append(cMinor)
stream2.append(rest1)
stream2.append(noteASharp)
stream2.show()
```

--------------------------------

### Running the music21 Test Suite

Source: https://github.com/cuthbertlab/music21/blob/master/AGENTS.md

Provides commands to run the music21 test suite using either a multiprocessing approach or a single-core approach, depending on the machine's capabilities.

```bash
music21/test/multiprocessTest.py
```

```bash
testSingleCoreAll.py
```

--------------------------------

### Get Directed Interval Value

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/usersGuide/usersGuide_20_examples2.ipynb

Retrieves the directed generic value of an interval.

```python
secondInterval = allIntervals[1]
secondInterval.generic.directed
```

--------------------------------

### Display Key Signature Octaves Example (13ac)

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/developerReference/musicxmlTest.ipynb

Tests key signatures at different octaves, including cancellation. Note: MuseScore and Finale do not support octave information for key signatures.

```python
s('13ac') # no music21 support; blocked MuseScore + Finale
```

--------------------------------

### Get Stream Representation

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/usersGuide/usersGuide_04_stream1.ipynb

Display the string representation of a music21 Stream object.

```python
stream1
```

--------------------------------

### Run Test Case '01d'

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/developerReference/musicxmlTest.ipynb

Executes the test case '01d' which covers microtones. It parses and displays MusicXML files containing various microtonal accidentals.

```python
s('01d')
```

--------------------------------

### Get Note Representation

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/usersGuide/usersGuide_04_stream1.ipynb

Display the string representation of a music21 Note object.

```python
note1
```

--------------------------------

### Get List Length

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/usersGuide/usersGuide_04_stream1.ipynb

Returns the number of elements currently in a Python list.

```python
len(noteList)
```

--------------------------------

### Multi-Staff with Different Keys and Clefs at Start

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/developerReference/musicxmlTest.ipynb

Demonstrates a piano staff where each staff has different keys and clefs, all defined at the beginning of the measure.

```python
s('43b')
```

--------------------------------

### Run All Music21 Tests (Single Core)

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/developerReference/testing.ipynb

Execute all tests for the music21 library on a single core. This method is used for modules that do not work well with multiprocessing or are in obscure subdirectories, and should be run before major releases.

```bash
python3 test/singleCoreAll.py
```

--------------------------------

### Get scale from KeySignature

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/usersGuide/usersGuide_15_key.ipynb

Retrieve the Major or Minor scale corresponding to a given KeySignature.

```python
ks2.getScale('major')
```

```python
ks2.getScale('minor')
```

--------------------------------

### Get Roman Numeral Key

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/usersGuide/usersGuide_23_romanNumerals.ipynb

Retrieves the `Key` object associated with each RomanNumeral object.

```python
(rf.key, rc.key, rb.key)
```

--------------------------------

### Get ID of a Part

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/usersGuide/usersGuide_12_music21object.ipynb

Retrieves the ID of a music21 Part object, which in this case is 'Soprano'.

```python
sopr.id
```

--------------------------------

### Access Stream Duration Type

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/usersGuide/usersGuide_04_stream1.ipynb

Get the type of the Duration object for a music21 Stream.

```python
stream1.duration.type
```

--------------------------------

### Typical Music21 Usage with Stream Manipulation

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/usersGuide/usersGuide_58_sitesContext.ipynb

Illustrates a common music21 pattern involving stream creation, insertion, and retrieval of notes. This example highlights how new streams are created and how the first note can change after modifications.

```python
p = stream.Part()
m = stream.Measure()
p.insert(0, m)
m.insert(1, note.Note('D'))
firstNote = p.recurse().notes.first()
m.insert(0, note.Note('C'))
newFirstNote = p.recurse().notes.first()
(firstNote, newFirstNote)
```

--------------------------------

### Get Note Duration

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/usersGuide/usersGuide_04_stream1.ipynb

Retrieves the duration of a music21 Note object in quarter lengths.

```python
note2.duration.quarterLength
```

--------------------------------

### Create KeySignature object

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/usersGuide/usersGuide_15_key.ipynb

Create a KeySignature object by specifying the number of sharps. Positive integers indicate sharps, while negative integers indicate flats.

```python
ks2 = key.KeySignature(2)
ks2.sharps
```

```python
ks7 = key.KeySignature(7)
ks7
```

--------------------------------

### Example Usage of getLastChord (Python)

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/usersGuide/usersGuide_20_examples2.ipynb

Demonstrates calling the getLastChord function with a BWV 10 score.

```python
getLastChord(bwv10)
```

--------------------------------

### Creating a Duration Object Directly

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/usersGuide/usersGuide_19_duration2.ipynb

Shows how to instantiate a music21 Duration object with a specified quarter length.

```python
d = duration.Duration(4.0)
d
```

--------------------------------

### Sphinx Italics Text Example

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/developerReference/documenting.rst

To italicize text in reStructuredText, enclose the text in single asterisks.

```rst
*This is italics*
```

--------------------------------

### Get Tonal Certainty of a Key Analysis

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/usersGuide/usersGuide_15_key.ipynb

Calculates the tonal certainty of a key analysis result.

```python
fis.tonalCertainty()
```

--------------------------------

### Create and Print Time Signature

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/usersGuide/usersGuide_14_timeSignatures.ipynb

Demonstrates creating a TimeSignature object and printing its numerator and denominator. Requires importing the music21 library.

```python
from music21 import *

noteC = note.Note('C4', type='half')
noteD = note.Note('D4', type='quarter')
noteE = note.Note('E4', type='quarter')
noteF = note.Note('F4', type='half')

tsThreeFour = meter.TimeSignature('3/4')

print(tsThreeFour.numerator, '/',  tsThreeFour.denominator)
```

--------------------------------

### Getting Score Length

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/usersGuide/usersGuide_06_stream2.ipynb

Retrieves the number of top-level elements within a music21 Score object.

```python
len(sBach)
```

--------------------------------

### Get Treble Clef Sign

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/usersGuide/usersGuide_31_clefs.ipynb

Retrieves the sign for a TrebleClef, which is 'G' for the standard treble clef.

```python
treble = clef.TrebleClef()
treble.sign
```

--------------------------------

### Write and Read Custom Format File

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/usersGuide/usersGuide_54_extendingConverter.ipynb

Write data to a temporary file with the '.sb' extension and then parse it using converter.parse(), demonstrating file handling.

```python
from music21 import environment
e = environment.Environment()
f = e.getTempFile('.sb')
with open(fp, 'w') as f:
    f.write('CDC DE F GAGB GE C DEFED C')

print(fp)
```

--------------------------------

### Create a chord from pitch classes and display it

Source: https://github.com/cuthbertlab/music21/blob/master/documentation/source/usersGuide/usersGuide_07_chords.ipynb

Constructs a chord using a list of pitch classes and displays its musical notation. Pitch classes are integers from 0 to 11.

```python
oddChord = chord.Chord([1, 3, 7, 9, 10])
oddChord.show()
```