frozenset() 函数返回不可修改的 frozenset 对象。它包含无序的对象集合，且不可更改，因此可以用作字典的键。
frozenset([iterable]) #Where iterable can be a list, string, tuple, dictionary , set etc
frozenset() 函数接受一个参数。如果提供了可迭代参数，它将从中返回一个 frozenset。该可迭代对象包含用于初始化 frozenset 的元素。
| 参数 | 描述 | 必需/可选 |
|---|---|---|
| 可迭代对象 | 可迭代对象可以是集合、字典、元组等。 | 可选 |
| 无参数 | 空的 frozenset 对象 | 可选 |
返回值为给定可迭代对象的不可变（不能修改）冻结集合。
| 输入 | 返回值 |
|---|---|
| 整型 | 一个整数冻结集合 |
| 字符 | 一个字符冻结集合 |
| 无参数 | 空集 |
# tuple of vowels
vowels = ('a', 'e', 'i', 'o', 'u')
fSet = frozenset(vowels)
print('The frozen set is:', fSet)
print('The empty frozen set is:', frozenset())
# frozensets are immutable
fSet.add('v')
输出
The frozen set is: frozenset({'a', 'o', 'u', 'i', 'e'})
The empty frozen set is: frozenset()
Traceback (most recent call last):
File ", line 8, in
fSet.add('v')
AttributeError: 'frozenset' object has no attribute 'add'
fs = frozenset([1, 2, 3, 4, 5, 4, 3])
for x in fs:
print(x)
输出
1 2 3 4 5
# random dictionary pers "John", "age": 23, "sex": "male"}
fSet = frozenset(person)
print('The frozen set is:', fSet)
输出
The frozen set is: frozenset({'name', 'sex', 'age'})
# Frozensets
# initialize A and B
A = frozenset([1, 2, 3, 4])
B = frozenset([3, 4, 5, 6])
# copying a frozenset
C = A.copy() # Output: frozenset({1, 2, 3, 4})
print(C)
# union
print(A.union(B)) # Output: frozenset({1, 2, 3, 4, 5, 6})
# intersection
print(A.intersection(B)) # Output: frozenset({3, 4})
# difference
print(A.difference(B)) # Output: frozenset({1, 2})
# symmetric_difference
print(A.symmetric_difference(B)) # Output: frozenset({1, 2, 5, 6})
输出
frozenset({1, 2, 3, 4})
frozenset({1, 2, 3, 4, 5, 6})
frozenset({3, 4})
frozenset({1, 2})
frozenset({1, 2, 5, 6})
# Frozensets
# initialize A, B and C
A = frozenset([1, 2, 3, 4])
B = frozenset([3, 4, 5, 6])
C = frozenset([5, 6])
# isdisjoint() method
print(A.isdisjoint(C)) # Output: True
# issubset() method
print(C.issubset(B)) # Output: True
# issuperset() method
print(B.issuperset(C)) # Output: True
输出
True True True
