Module `dalpy.sets`

Module that holds classes related to sets.

This module contains the Set class. Set represents a set.

Examples

Creating a Set, adding elements, and checking membership:

s = Set()
s.union(Set(1))
s.union(Set(2,3))
if 1 in s:
    print("1")

Removing elements from a Set:

t = Set(3,4)
s.difference(t)

Classes

class Set (*initial_elements)

Represents a set.

This class represents a set that preserves insertion order. This allows for it to be used in cases where the order of the set's contents must be deterministic.

Examples

To initialize an empty Set:

s = Set()

To add elements to s use union with another Set:

s.union(Set(1))
r = Set(2,3)
s.union(r)

To check if s contains an element:

if 1 in s:
    # Do something

To remove a Set of elements from s, make use of difference:

t = Set(2,3)
s.difference(t)

To remove one element from s, make use of the ability to create a singleton set combined with difference:

s.difference(Set(1))

To iterate over a Set:

for e in s:
    # Do something with e

Initializes a Set in O(1) time.

Args

initial_elements: To initialize the Set to contain some elements, pass any number of arguments separated by commas that will be passed via this variable length arguments parameter.

Methods

def difference(self, other_set)

Performs a set difference operation on this Set.

This method removes all the elements from this Set that occur in another set. Calling s.difference(Set(1)) on a Set s is akin to s = s - {1}. This runs in O(n) time where n is the size of the other Set.

Args

other_set: Another Set specifying the elements to be removed from this Set. This Set is unaffected by this method.

Raises

TypeError: If other_set is not a Set.

def is_empty(self)

Returns True if this Set is empty, False otherwise in O(1) time w/r/t the size of this Set.

def size(self)

Returns the integer number of elements in this Set in O(1) time w/r/t the size of this Set.

def union(self, other_set)

Performs a set union operation on this Set.

This method adds all the elements from another Set into this Set that do not already exist in this Set. Calling s.union(Set(1)) on a Set s is akin to s = s U {1}. This runs in O(n) time where n is the size of the other Set.

Args

other_set: Another Set specifying the elements to be added to this Set if they do not already exist. This Set is unaffected by this method.

Raises

TypeError: If other_set is not a Set.