alex_pythonday3

 1 # author:"Jason lincoln"
 2 list_1={1,4,5,7,3,6,7,9}
 3 list_1=set(list_1)  #把集合变成列表 去重复
 4 
 5 list_2=set([2,6,0,66,22,8,4])
 6 print(list_1,type(list_1))
 7 print(list_2)
 8 print(list_1.intersection(list_2))  #交集
 9 print(list_1.union(list_2))         #并集
10 print(list_1.difference(list_2))    #差集
11 #子集
12 list_3=set([1,3,7])
13 print(list_3.issubset(list_1))      #list_3包含于list_1
14 print(list_1.issuperset(list_3))    #list_1包含list_1
15 
16 #对称差集
17 
18 print(list_1.symmetric_difference(list_2))  #并集然后去掉相同部分
19 list_4=set([5,7,8])
20 print(list_3.isdisjoint(list_4))            #有交集返回False没交集返回True
21 #交集
22 print(list_1 & list_2)
23 #并集
24 print(list_1 | list_2)
25 #差集
26 print(list_1 - list_2)  # in list_1 but not in list_2
27 #对称差集
28 print(list_1 ^ list_2)

1 list_1.add(999)        #添加一项
2 list_1.update([888,777]) #添加多项
3 print(list_1)
4 print(list_1.remove(777))     #删除
5 list_1.discard(888)    #删除集合里面没有的元素不会报错
6 print(list_1)
7 print(len(list_1))
8 print(list_1.pop()) #随机删除然后返回删除的那个数

 1 author:"Jason lincoln"
 2 
 3 # author:"Jason lincoln"
 4 
 5 #data=open("yesterday",encoding="utf-8").read()
 6 #f=open("yesterday",‘r‘,encoding="utf-8")  #文件句柄
 7 #f=open("yesterday2",‘w‘,encoding="utf-8")  #建一个新文件
 8 f=open("yesterday2",‘a‘,encoding="utf-8")  # a==append 追加
 9 
10 
11 f.write("\nwhen i was young ,i‘d like listen to the radio")
12 f.write(‘\n天安门上太阳升。。。‘)
13 f.close()