Last modified: October 27, 2015
Contents
In module gamera.toolkits.musicstaves.equivalence_grouper
This class provides an easy way to parttion a set into equivalence classes, i.e. disjoint subsets where the members in each subset are equivalent.
Objects can be joined using .join(), tested for equivalence using .joined(), and all disjoint sets can be retrieved using an iterator over the class.
The objects being joined must be hashable.
from equivalence_grouper import EquivalenceGrouper
g = EquivalenceGrouper()
# mark items as equivalent
g.join('a', 'b')
g.join('b', 'c')
g.join('d', 'e')
# all classes can be accessed by iterating over g
[c for c in g]
>>> [['a', 'b', 'c'], ['d', 'e']]
# check for equivalence
g.joined('a', 'b')
>>> True
# transitivity is automatically detected
g.joined('a', 'c')
>>> True
g.joined('a', 'd')
>>> False
| Author: | Michael Droettboom and Christoph Dalitz |
|---|
Optionally you can provide a list of items to the constructor which are first considered not to be equivalent. You can use .join() afterwards to mark items as equivalent and/or to add addiitonal items.
Join given arguments into the same subset, i.e. mark them as equivalent.
Items not yet part of any subset are added in a new subset. Accepts one or more arguments. To just add a new item x to the superset, just call .join(x).
Returns True if a and b are equivalent, i.e. are members of the same subset (equivalence class).
Returns an iterator returning each of the disjoint subsets as a list.