1.字典与集合的关系

集合是一个无序的，不重复的数据组合

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a={}
b={1,2,3,4,5}
print(type(a)) # <class 'dict'>
print(type(b)) # <class 'set'>

2.集合的创建

2.1 如上面的b集合，直接{}里面包括key

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b={1,2,3,4,5}

2.2 set()方法：set(列表)

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a = set([1,2,3,4,5])
print(a) # {1, 2, 3, 4, 5}

3.集合不可重复

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a = set([1,1,2,2,3,3,4,4,5,5])
print(a) # {1, 2, 3, 4, 5}

如去除列表重复的元素

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a = [1,2,3,4,5,1,2,3,4,5,6,0]
a = list(set(a))
print(a) #[0, 1, 2, 3, 4, 5, 6] ==> 0 放在首位了

4.集合add()

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a = {1,2,3,4,5,6}
a.add(5)
print(a) #{1, 2, 3, 4, 5, 6} 添加已有元素不会添加
a.add(7)
print(a) # {1, 2, 3, 4, 5, 6, 7}
a.update([7,8,9])
print(a) # {1, 2, 3, 4, 5, 6, 7, 8, 9}

5.集合移除remove()

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a = {1,2,3,4,5,6}
a.remove(4)
print(a) # {1, 2, 3, 5, 6}

6.集合的与&、 或|、 与非^、 操作

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a = {1,2,3,4,5,6}
b = {1,2,8,9}
c = a & b
print(c) # {1, 2}
d = a | b
print(d) # {1, 2, 3, 4, 5, 6, 8, 9}
e = a ^ b
print(e) # {3, 4, 5, 6, 8, 9}

7.集合的不可变forzenser()

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a = {1,2,3,4,5,6}
a = frozenset(list(a))
print(a) # frozenset({1, 2, 3, 4, 5, 6})
a.add(8)
print(a) # 报错 Traceback (most recent call last):