python set 一些用法

add(增加元素)

name = set(['Tom','Lucy','Ben'])

name.add('Juny')

print(name)#输出：{'Lucy', 'Juny', 'Ben', 'Tom'}

clear(清空所有元素)

name = set(['Tom','Lucy','Ben'])

name.clear()

print(name)#输出：set()

copy(拷贝set集合)

name = set(['Tom','Lucy','Ben'])

new_name = name.copy()

print(new_name)#输出：{'Tom', 'Lucy', 'Ben'}

difference(返回两个或多个集合中不同的元素，并生成新的集合)

A = set([2,3,4,5])

B = set([4,5])

A.difference_update(B)

print(A)#输出：{2, 3}

discard(移除元素)

n = set([2,3,4])

n.discard(3)

print(n)#输出：{2, 4}

intersection(取交集，并生成新的集合)

n1 = set([2,3,4,5])

n2 = set([4,5,6,7])

n = n1.intersection(n2)

print(n)#输出：{4, 5}

intersection_update(取交集，修改原来的集合)

n1 = set([2,3,4,5])

n2 = set([4,5,6,7])

n1.intersection_update(n2)

print(n1)#输出：{4, 5}

isdisjoint(判断交集，是返回False，否返回True)

n1 = set([2,3,4,5])
n2 = set([4,5,6,7])
print(n1.isdisjoint(n2))#输出：False

issubset(判断子集)

A = set([2,3])

B = set([2,3,4,5])

print(A.issubset(B))#输出：True#A是B的子集

issuperset(判断父集)

A = set([2,3])

B = set([2,3,4,5])

print(B.issuperset(A))# 输出：True#B是A的父集

pop(随机移除一个元素)

n = set([2,3,4,5])

n1 = n.pop()

print(n,n1)# 输出：{3, 4, 5} 2

remove(移除指定元素)

n = set([2,3,4,5])

n.remove(2)

print(n)# 输出：{3, 4, 5}

symmetric_difference(取交集，并生成新的集合)

A = set([2,3,4,5])

B = set([4,5,6,7])

print(A.symmetric_difference(B))# 输出：{2, 3, 6, 7}

symmetric_difference_update(取交集，改变原来的集合)

A = set([2,3,4,5])

B = set([4,5,6,7])

A.symmetric_difference_update(B)

print(A)# 输出：{2, 3, 6, 7}

union(取并集，并生成新的集合)

A = set([2,3,4,5])

B = set([4,5,6,7])

print(A.union(B))# 输出：{2, 3, 4, 5, 6, 7}

update(取并集，改变原来的集合)

A = set([2,3,4,5])

B = set([4,5,6,7])

A.update(B)print(A)# 输出：{2, 3, 4, 5, 6, 7}