Set

A collection of unique items, unordered and unindexed.

Create

Create a set

Action	Code	Details
Empty set	set()	{} defines a dictionary!
Define with values	{'apple', 'banana', 'pear'}
From tuple	set(x)
From list	set(x)
From iterable (consumes)	set(x)
Union from a collection of sets	set().union(*x)

Test

Action	Code	Details
Is set or subclass	isinstance(x, set)
Is set and not subclass	type(x) is set
Empty	not x
Not empty	x
Contains value v	v in x
Contains None	None in x
Contains all of the given values	{v1, v2}.issubset(x)
Contains all of the given values	x.issuperset([v1, v2])
Contains any of the given values	not x.isdisjoint([v1, v2])
Contains none of the given values	x.isdisjoint([v1, v2])

Compare with another set

Action	Code	Details
Sets share no values	x.isdisjoint(y)
Set is a subset of the other: all values of x are in y	x.issubset(y)
Set is a superset of the other: all values of y are in x	x.issuperset(y)

Extract

Action	Code	Details
Number of (unique) values	len(x)
Hash	hash(frozenset(x))

Update

Grow

Action	Code	Details
Add value if needed	x.add('strawberry')
Add multiple values if needed	x.update(['strawberry', 'kiwi'])

Shrink

Action	Code	Details
Remove all values (clear)	x.clear()
Remove value	x.remove('strawberry')	Throws error if value is missing
Remove value if needed	x.discard('strawberry')

Derive

Combine

Combine with another set

Action	Code	Details
Union with another set	x | y
Union with another set	x.union(y)
Intersection with another set: get values which are present in both sets	x & y
Intersection with another set: get values which are present in both sets	x.intersect(y)
Difference to another set: get values which are not present in the other set	x - y
Difference to another set: get values which are not present in the other set	x.difference(y)
Symmetric difference with another set: get values that are not present in both sets	x ^ y
Symmetric difference with another set: get values that are not present in both sets	x.symmetric_difference(y)

Convert

The order of the values in the output should not be relied on

Action	Code	Details
Tuple of values	tuple(x)
List of values	list(x)