python 集合总结

‘‘‘
集合:1:他是无序的,他是不重复的.
     2,他里面的元素必须是可哈希的. int str bool ()但是它本身是不可哈希的.
     3,集合不能更改里面的元素.
     4,集合可以求交集,并集,差集,反交集等.
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# lis = [1,1,2,2,3,3,3,4,5,6,6,7]
#去重:
    #1,用算法去做.
    #2,转换成集合.在转换过来.
# set1 = set(lis)
# lis = list(set1)
# print(lis)
#创建集合:
# set1 = set({1,2,‘alex‘})
# set1 = {‘alex‘,‘wusir‘,‘ritian‘,‘egon‘,‘barry‘}
#增:
# print(set1)
#add 添加一个元素=========================
# set1.add(‘景女神‘)
# print(set1)
# #update 迭代着添加=======================
# set1.update(‘abc‘)
# set1.update([1,2,3])
# print(set1)

#删除
#按照元素去删除============================
# set1.remove(‘ritian‘)
# print(set1)
#随机删除 pop==========================
# set1.pop()
# print(set1)

#清空集合 clear()=========================
# set1.clear()
# print(set1)
#删除 集合==========================
# del set1
# print(set1)

#查:
# for i in set1:=========遍历查询集合===============
#     print(i)

#交集 &  intersection
# set1 = {1,2,3,4,5}
# set2 = {4,5,6,7,8}
# set3 = set1 & set2
# print(set3)
# print(set1.intersection(set2))

#并集 | union
# print(set1 | set2)
# print(set1.union(set2))
#反交集 ^ symmetric_difference
# print(set1 ^ set2)
# print(set1.symmetric_difference(set2))

#差集 -  difference
# print(set1 - set2)
# print(set2 - set1)
# print(set1.difference(set2))
set1 = {1,2,3}
set2 = {1,2,3,4,5,6}
#超集  <  issubset
# print(set1 < set2)
# print(set1.issubset(set2))
# print(set1.issuperset(set2))
# print(set2.issuperset(set1))

# s2 = frozenset(set1)
# print(s2,type(s2))