7.0 Python: frozenset
7.1 Python frozenset
frozenset is an immutable version of a set.
Like sets, it contains unique, unordered, unchangeable elements.
Unlike sets, elements cannot be added or removed from a frozenset.
7.2 Creating a forzenset
Use the frozenset() constructor to create a frozenset from any iterable.
7.2.1 Example
Create a frozenset and check its type:
x = frozenset({"apple", "banana", "cherry"})
print(x)
print(type(x))
7.3 Frozenset Methods
Being immutable means you cannot add or remove elements. However, frozensets support all non-mutating operations of sets.
| Method | Shortcut | Description |
|---|---|---|
copy() | Returns a shallow copy | |
difference() | - | Returns a new frozenset with the difference |
intersection() | & | Returns a new frozenset with the intersection |
isdisjoint() | Returns whether two frozensets have an intersection | |
issubset() | <= / < | Returns True if this frozenset is a (proper) subset of another |
issuperset() | >= / > | Returns True if this frozenset is a (proper) superset of another |
symmetric_difference() | ^ | Returns a new frozenset with the symmetric differences |
union() | | | Returns a new frozenset containing the union |