music21.corpus.chorales¶
This file makes it easier to access Bach’s chorales through various numbering schemes and filters and includes the corpus.chorales.Iterator() class for easily iterating through the chorale collection.
ChoraleList¶
- class music21.corpus.chorales.ChoraleList¶
A searchable list of Bach’s chorales by various numbering systems:
Note that multiple chorales share the same title, so it’s best to iterate over one of the other lists to get them all.
The list of chorales comes from https://en.wikipedia.org/wiki/List_of_chorale_harmonisations_by_Johann_Sebastian_Bach which does not have all chorales in the Bärenreitter-Kirnberger or Riemenschneider numberings since it only includes BWV 250-438.
>>> bcl = corpus.chorales.ChoraleList() >>> info358 = bcl.byBudapest[358] >>> for key in sorted(list(info358)): ... print(f'{key} {info358[key]}') baerenreiter 68 budapest 358 bwv 431 kalmus 358 notes None riemenschneider 68 title Wenn wir in höchsten Nöten sein >>> c = corpus.parse('bach/bwv' + str(info358['bwv'])) >>> c.show() # shows Bach BWV431
More fully:
>>> b = corpus.parse('bwv' + str(corpus.chorales.ChoraleList().byRiemenschneider[2]['bwv'])) >>> b <music21.stream.Score ...>
ChoraleList
methods
- ChoraleList.prepareList()¶
puts a list of Bach Chorales into dicts of dicts called
self.byBudapest self.byBWV self.byRiemenschneider
etc.
ChoraleListRKBWV¶
- class music21.corpus.chorales.ChoraleListRKBWV¶
A searchable list of Bach’s chorales by various numbering systems:
Note that multiple chorales share the same title, so it’s best to iterate over one of the other lists to get them all.
The list of chorales comes from Margaret Greentree (formerly at jsbchorales.net) who compiled all chorales in the corpus, but only had numbers for the kalmus, riemenschneider, and bwv numbering systems.
>>> bcl = corpus.chorales.ChoraleListRKBWV() >>> info155 = bcl.byRiemenschneider[155] >>> for key in sorted(list(info155)): ... print(f'{key} {info155[key]}') bwv 344 kalmus 173 riemenschneider 155 title Hilf, Herr Jesu, laß gelingen >>> c = corpus.parse('bach/bwv' + str(info155['bwv'])) >>> c.show() # shows Bach BWV344
More fully:
>>> theNumber = corpus.chorales.ChoraleListRKBWV().byRiemenschneider[2]['bwv'] >>> b = corpus.parse('bwv' + str(theNumber)) >>> b <music21.stream.Score ...>
ChoraleListRKBWV
methods
- ChoraleListRKBWV.prepareList()¶
puts a list of Bach Chorales into dicts of dicts called
self.byKalmus self.byBWV self.byRiemenschneider self.byTitle
Iterator¶
- class music21.corpus.chorales.Iterator(currentNumber: int | None = None, highestNumber: int | None = None, *, numberingSystem: str = 'riemenschneider', returnType: str = 'stream', iterationType: str = 'number', analysis: bool = False, numberList: list[int] | None = None, titleList: list[str] | None = None)¶
This is a class for iterating over many Bach Chorales. It is designed to make it easier to use one of music21’s most accessible datasets. It will parse each chorale in the selected range in a lazy fashion so that a list of chorales need not be parsed up front. To select a range of chorales, first select a .numberingSystem (‘riemenschneider’, ‘bwv’, ‘kalmus’, ‘budapest’, ‘baerenreiter’, or ‘title’). Then, set .currentNumber to the lowest number in the range and .highestNumber to the highest in the range. This can either be done by catalogue number (iterationType = ‘number’) or by index (iterationType = ‘index’).
Note that these numbers are 1-indexed (as most catalogues are) and unlike Python’s range feature, the final number is included.
Changing the numberingSystem will reset the iterator and change the range values to span the entire numberList. The iterator can be initialized with three parameters (currentNumber, highestNumber, numberingSystem). For example corpus.chorales.Iterator(1, 26,’riemenschneider’) iterates through the riemenschneider numbered chorales from 1 to 26. Additionally, the following keywords can be set:
returnType = either ‘stream’ (default) or ‘filename’
iterationType = either ‘number’ or ‘index’
titleList = [list, of, titles]
numberList = [list, of, numbers]
>>> for chorale in corpus.chorales.Iterator(1, 4, returnType='filename'): ... print(chorale) bach/bwv269 bach/bwv347 bach/bwv153.1 bach/bwv86.6
>>> BCI = corpus.chorales.Iterator() >>> BCI.numberingSystem 'riemenschneider'
>>> BCI.currentNumber 1
>>> BCI.highestNumber 371
An Exception will be raised if the number set is not in the numbering system selected, or if the numbering system selected is not valid.
>>> BCI.currentNumber = 377 Traceback (most recent call last): ... music21.corpus.chorales.BachException: 377 does not correspond to a chorale in the riemenschneider numbering system
>>> BCI.numberingSystem = 'not a numbering system' Traceback (most recent call last): ... music21.corpus.chorales.BachException: not a numbering system is not a valid numbering system for Bach Chorales.
If the numberingSystem ‘title’ is selected, the iterator must be initialized with a list of titles. It will iterate through the titles in the order of the list.
>>> BCI.numberingSystem = 'title' >>> BCI.returnType = 'filename' >>> BCI.titleList = ['Jesu, meine Freude', ... 'Gott hat das Evangelium', ... 'Not a Chorale'] 'Not a Chorale' will be skipped because it is not a recognized title.
>>> for chorale in BCI: ... print(chorale) bach/bwv358 bach/bwv319
The numberList, which, by default, includes all chorales in the chosen numberingSystem, can be set like the titleList. In the following example, note that the first chorale in the given numberList will not be part of the iteration because the first currentNumber is set to 2 at the start by the first argument. (If iterationType==’index’, setting the currentNumber to 1 and the highestNumber to 7 would have the same effect as the given example.
>>> BCI = corpus.chorales.Iterator(2, 371, numberingSystem='riemenschneider', ... numberList=[1, 2, 3, 4, 6, 190, 371, 500], ... returnType='filename') 500 will be skipped because it is not in the numberingSystem riemenschneider
>>> for chorale in BCI: ... print(chorale) bach/bwv347 bach/bwv153.1 bach/bwv86.6 bach/bwv281 bach/bwv337 bach/bwv278
Elements in the iterator can be accessed by index as well as slice.
>>> for chorale in corpus.chorales.Iterator(returnType='filename')[4:10]: ... print(chorale) bach/bwv86.6 bach/bwv267 bach/bwv281 bach/bwv17.7 bach/bwv40.8 bach/bwv248.12-2 bach/bwv38.6
>>> print(corpus.chorales.Iterator(returnType='filename')[55]) bach/bwv121.6
For the first 20 chorales in the Riemenschneider numbering system, there are professionally annotated roman numeral analyses in romanText format, courtesy of Dmitri Tymoczko of Princeton University. To get them as an additional part to the score set returnType to “stream”, and add a keyword “analysis = True”:
If chorales are accessed through the Iterator(), the metadata.title attribute will have the correct German title. This is different from the metadata returned by the parser which does not give the German title but rather the BWV number.
>>> corpus.chorales.Iterator(returnType='stream')[1].metadata.title 'Ich dank’ dir, lieber Herre'
Iterator
read/write properties
- Iterator.currentNumber¶
The currentNumber is the number of the chorale (in the set numberingSystem) for the next chorale to be parsed by the iterator. It is initially the first chorale in whatever numberingSystem is set, but it can be changed to any other number in the numberingSystem as desired as long as it does not go above the highestNumber which is the boundary of the iteration.
- Iterator.highestNumber¶
The highestNumber is the number of the chorale (in the set numberingSystem) for the last chorale to be parsed by the iterator. It is initially the highest numbered chorale in whatever numberingSystem is set, but it can be changed to any other number in the numberingSystem as desired as long as it does not go below the currentNumber of the iteration.
- Iterator.iterationType¶
This property determines how boundary numbers are interpreted, as indices or as catalogue numbers.
- Iterator.numberList¶
Allows access to the catalogue numbers (or indices if iterationType == ‘index’) that will be iterated over. This can be set to a specific list of numbers. The list will be sorted.
- Iterator.numberingSystem¶
This property determines which numbering system to iterate through chorales with. It can be set to ‘bwv’, ‘kalmus’, ‘baerenreiter’, ‘budapest’, or ‘riemenschneider’. It can also be set to ‘title’ in which case the iterator needs to be given a list of chorale titles in .titleList. At this time, the titles need to be exactly as they appear in the dictionary it queries.
- Iterator.returnType¶
This property determines what the iterator returns; ‘stream’ is the default and causes the iterator to parse each chorale. If this is set to ‘filename’, the iterator will return the filename of each chorale but not parse it.
- Iterator.titleList¶
A list of titles to iterate over if .numberingSystem is set to ‘title’.
Iterator
methods
- Iterator.__getitem__(key)¶
Functions¶
- music21.corpus.chorales.getByTitle(title)¶
Return a Chorale by title (or title fragment) or None
>>> germanTitle = "Sach' Gott heimgestellt" >>> c = corpus.chorales.getByTitle(germanTitle) >>> c.metadata.title "Ich hab' mein' Sach' Gott heimgestellt"