Python frozenset()

frozenset()函数返回不能修改的 frozenset 对象。它包含一个无序的对象集合，并且是不可更改的，因此它可以用作字典中的键。

 **frozenset([iterable])** #Where iterable can be a list, string, tuple, dictionary , set etc 

frozenset()参数:

frozenset()函数接受一个参数。如果给定了 iterable 参数，它将从中返回一个 frozenset。iterable 包含初始化 frozenset 的元素。

frozenset()返回值

返回值是给定 iterable 的不可变(不能修改)的冻结集。

| 投入 | 返回值 |
| 整数 | 整数冻结集 |
| 性格；角色；字母 | 冻结字符集 |
| 无参数 | 空集 |

Python 中frozenset()方法的示例

示例 Python frozenset()的工作原理

 # 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 "<string>, line 8, in <module>fSet.add('v')
AttributeError: 'frozenset' object has no attribute 'add'</module></string> 

示例 2:创建整数frozenset()

 fs = frozenset([1, 2, 3, 4, 5, 4, 3])
for x in fs:
    print(x) 

输出:

 1
2
3
4
5 

示例 3:字典的frozenset()

 # 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'}) 

示例 4: Frozenset()处理复制、差、交集、对称差和并集等操作

 # 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}) 

示例 5: Frozenset()处理像 isdisjoint、issubset 和 issuperset 这样的方法

 # 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