集合的特性
不同元素组成
无序
集合中的元素必须时不可变类型
集合的方法
add
1 #赋值 2 a = {1,2,3,4,5,6,7,"hello world"} 3 4 #将子元素添加到集合a中 5 a.add("add") 6 7 #输出 8 print (a) 9 10 11 #结果 12 {1, 2, 3, 4, 5, 6, 7, 'add', 'hello world'}
clear
#赋值 a = {1,2,3,4,5,6,7,"hello world"} #清空集合 a.clear() #输出 print (a) #结果 set()
copy
1 #赋值 2 a = {1,2,3,4,5,6,7,"hello world"} 3 4 #拷贝 5 b = a.copy() 6 7 #输出 8 print (b) 9 10 11 #结果 12 {1, 2, 3, 4, 5, 6, 7, 'hello world'}
difference
1 #赋值 2 a = {1,2,3,4,5,6,7,"hello world"} 3 b = {1,2,3,4,5,'hello world'} 4 5 #求a与b的差集（a - b 等效） 6 c = a.difference(b) 7 d = a - b 8 9 #输出 10 print (c) 11 print (d) 12 13 14 #结果 15 {6, 7} 16 {6, 7}
difference_update
1 #赋值 2 a = {1,2,3,4,5,6,7,"hello world"} 3 b = {1,2,3,4,5,'hello world'} 4 5 #求a与b的差集,更新到a中，没有返回值 6 c = a.difference_update(b) 7 8 #输出 9 print (a) 10 print (c) 11 12 13 #结果 14 {6, 7} 15 None
discard
#赋值 a = {1,2,3,4,5,6,7,"hello world"} b = {1,2,3,4,5,'hello world'} #删除集合中指定的元素，不返回值 c = a.discard('hello world') #输出 print (a) print (c) #结果 {1, 2, 3, 4, 5, 6, 7} None
intersection
1 #赋值 2 a = {1,2,3,4,5,6,7,"hello world"} 3 b = {1,2,3,4,5,'hello world'} 4 5 #求交集 6 c = a.intersection(b) 7 d = a & b #等效 8 9 10 #输出 11 print (c) 12 print (d) 13 14 15 #结果 16 {1, 2, 3, 4, 5, 'hello world'} 17 {1, 2, 3, 4, 5, 'hello world'}
intersection_update
1 #赋值 2 a = {1,2,3,4,5,6,7,"hello world"} 3 b = {1,2,3,4,5,'hello world'} 4 5 #求交集,并更新到集合a，没有返回值 6 c = a.intersection_update(b) 7 8 9 #输出 10 print (a) 11 print (c) 12 13 14 #结果 15 {1, 2, 3, 4, 5, 'hello world'} 16 None
isdisjoint
1 #赋值 2 a = {1,2,3,4,5,6,7,"hello world"} 3 b = {1,2,3,4,5,'hello world'} 4 c = {111,222} 5 6 #如果没有交集返回ture 7 d = a.isdisjoint(b) 8 e = c.isdisjoint(b) 9 10 11 #输出 12 print (d) 13 print (e)
issubset
1 #赋值 2 a = {1,2,3,4,5,6,7,"hello world"} 3 b = {1,2,3,4,5,'hello world'} 4 c = {111,222} 5 6 #是否子集 7 d = b.issubset(a) 8 e = b.issubset(c) 9 10 11 #输出 12 print (d) 13 print (e) 14 15 16 #结果 17 True 18 False
issuperset
#赋值 a = {1,2,3,4,5,6,7,"hello world"} b = {1,2,3,4,5} c = {111,222} #是否父集 d = a.issuperset(b) e = c.issuperset(b) #输出 print (d) print (e) #结果 print (d) print (e)
pop
1 #赋值 2 a = {"hello",2,3,4,5,6,7,"hello world"} 3 4 #随机删除一个元素，并返回 5 b = a.pop() 6 7 #输出 8 print (b) 9 10 11 #结果 12 hello
remove
1 #赋值 2 a = {"hello",2,3,4,5,6,7,"hello world"} 3 4 #指定删除一个元素，不返回值 5 b = a.remove(4) 6 7 #输出 8 print (a) 9 print (b) 10 11 12 #结果 13 {2, 3, 5, 6, 7, 'hello', 'hello world'} 14 None
symmetric_difference
1 #赋值 2 a = {"hello",2,3,4,5,6,7,"hello world"} 3 b = {'hello','hello world'} 4 5 #交叉补集 6 c = a.symmetric_difference(b) 7 8 #输出 9 print (c) 10 11 #结果 12 {2, 3, 4, 5, 6, 7}
symmetric_difference_update
1 #赋值 2 a = {"hello",2,3,4,5,6,7,"hello world"} 3 b = {'hello','hello world'} 4 5 #交叉补集,并跟新到集合a中 6 a.symmetric_difference_update(b) 7 8 #输出 9 print (a) 10 11 12 #结果 13 {2, 3, 4, 5, 6, 7}
union
1 #赋值 2 a = {1,2,3,4,5,6,7,} 3 b = {'hello','hello world'} 4 5 #求并集 6 c = a.union(b) 7 d = a ^ b #等效 8 9 #输出 10 print (c) 11 print (d) 12 13 14 15 #结果 16 {1, 2, 3, 4, 5, 6, 7, 'hello world', 'hello'} 17 {1, 2, 3, 'hello world', 4, 5, 6, 7, 'hello'}
update
1 #赋值 2 a = {1,2,3,4,5,6,7,} 3 b = {'hello','hello world'} 4 5 #将集合b(或者元素)更新到集合a中 6 a.update(b) 7 8 #结果 9 print (a) 10 11 12 13 #结果 14 {1, 2, 3, 4, 5, 6, 7, 'hello', 'hello world'}