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data-structures 0.1.2

Python Data Structures - bags/multisets and setlists


A few collections/data structures that I think should be part of python. Python3 that is, I don't plan on supporting old versions. Maybe 2.7, I'm not sure what the deal with that is.

For now, this package includes one module - collections_extended. This module extends the built-in collections module to include a bag class, AKA multiset, and a setlist class, which is a list of unique elements or an ordered set depending on how you look at it. There are also frozen (hashable) varieties of each included. Finally, all collections are abstracted into one Collection abstract base class and a Collection factory is provided where you can create a Collection by specifying the properties unique, ordered and mutable.


To replace the built in collections module do:
import collections_extended as collections
To get the basic data structures:
from collections_extended import bag, frozenbag, setlist, frozensetlist
Or you can simply:
from collections_extended import *


There are four new classes provided:

This is a bag AKA multiset. See
This is a frozen (hashable) version of a bag.
An ordered set or a list of unique elements depending on how you look at it.
This is a frozen (hashable) version of a setlist.


Bags have constant time inclusion testing.

  • count(elem)

    Returns the count of elem in the bag. O(1)

  • num_unique_elements()

    Returns the number of unique elements in the bag. O(1)

  • unique_elements()

    Returns a set of all the unique elements in the bag. O(1)

  • nlargest(n=None)

    Returns the n most common elements and their counts from most common to least. If n is None then all elements are returned. O(n log n)

  • copy()

    Returns a shallow copy of self. O(self.num_unique_elements())

  • cardinality()

    Returns the cardinality of this bag. Same as len(self). O(1)

  • underlying_set()

    Returns the underlying set. Same as self.unique_elements().

  • multiplicity(elem)

    Same as self.count(elem)

  • isdisjoint(other: Iterable)

    Tests if self is disjoint with any other Iterable. O(len(other))

The following are only for mutable bags (not frozenbags).

  • pop()
  • add(elem)
  • discard(elem)
  • remove(elem)
  • clear()

Collection Factory

A Collection factory is provided where you can specify whether you want the Collection returned to be mutable, have unique elements and/or be ordered. If an Iterable object is passed the Collection will be filled from it, otherwise it will be empty.

collection(it: Iterable = None, mutable=True, unique=False, ordered=False)

File Type Py Version Uploaded on Size
data-structures-0.1.2.tar.gz (md5) Source 2009-10-04 11KB
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