set
特点：
集合 是一个无序的， 不重复的数据组合，它的主要作用有：
去重 把一个列表变成集合， 就自动去重了
集合中的元素必须是不可变元素
创建集合
s = {1,2,3,4,5,3,5,1}
print(s)
print(type(s))
# {1, 2, 3, 4, 5}
# <class 'set'>
交集
s = {1,2,3,4,5,3,5,1}
ss = {2,3,4}
# &
# intersection()
print("s与ss的交集： ",s.intersection(ss))
print("s与ss的交集： ",s&ss)
# s与ss的交集： {2, 3, 4}
# s与ss的交集： {2, 3, 4}
并集
s = {1,2,3,4,5,3,5,1}
ss = {2,3,4}
# 并集 等于2个列表去重
# union
# |
print("s与ss的并集： ",s.union(ss))
print("s与ss的并集: ", s|ss )
# s与ss的并集： {1, 2, 3, 4, 5}
# s与ss的并集: {1, 2, 3, 4, 5}
差集
s = {1,2,3,4,5,3,5,1}
ss = {2,3,4}
# difference
#-
print("s与ss的差集： ",s.difference(ss))
print("s与ss的差集： ",s-ss)
# s与ss的差集： {1, 5}
# s与ss的差集： {1, 5}
对称差集
s = {1,2,3,4,5,3,5,1}
ss = {2,3,4,333}
#symmetric_difference
#^
print(s.symmetric_difference(ss))
print(s^ss)
# {1, 5, 333}
# {1, 5, 333}
issubset
# #issubset
s = {1,2,3,4,5,3,5,1,333}
ss = {2,3,4,333}
# ss是s的子集
print(ss.issubset(s))
# True
# s 是ss的子集
print(s.issubset(ss))
# False
issuperset
# #issuperset
s = {1,2,3,4,5,3,5,1,333}
ss = {2,3,4,333}
# s 是ss的父集
print(s.issuperset(ss))
# True
# ss是 s的父集
print(ss.issuperset(s))
# False
元素的添加
a = {1,2}
a.update([1,34,5,6,67])
# update 添加多个元素
a.add("wwww")
# add 添加一个元素
print(a)
元素的删除
discard 存在就删除， 不存在也不报错
s = {1,2,3,4,5,3,5,1,333}
# # 元素的删除
# discard 存在就删除， 不存在 也不报错
s.discard('2ww')
print(s)
# {1, 2, 3, 4, 5, 333}
remove
s = {1,2,3,4,5,3,5,1,333}
s.remove('x') # 不存在会抛出 KeyError错误
Traceback (most recent call last):
File "D:/python/luffycity/元组/集合类型.py", line 135, in <module>
s.remove('x') # 不存在会抛出 KeyError错误
KeyError: 'x'
元素的源码
class set(object):
"""
set() -> new empty set object
set(iterable) -> new set object
Build an unordered collection of unique elements.
"""
def add(self, *args, **kwargs): # real signature unknown
"""
Add an element to a set.
This has no effect if the element is already present.
"""
pass
def clear(self, *args, **kwargs): # real signature unknown
""" Remove all elements from this set. """
pass
def copy(self, *args, **kwargs): # real signature unknown
""" Return a shallow copy of a set. """
pass
def difference(self, *args, **kwargs): # real signature unknown
"""
Return the difference of two or more sets as a new set.
相当于 s1 - s2 差集
(i.e. all elements that are in this set but not the others.)
"""
pass
def difference_update(self, *args, **kwargs): # real signature unknown
""" Remove all elements of another set from this set. """
pass
def discard(self, *args, **kwargs): # real signature unknown
"""
Remove an element from a set if it is a member.
与remove功能相同，删除元素不存在时不会抛出异常
If the element is not a member, do nothing.
"""
pass
def intersection(self, *args, **kwargs): # real signature unknown
"""
Return the intersection of two sets as a new set.
相当于 s1&s2 求交集
(i.e. all elements that are in both sets.)
"""
pass
def intersection_update(self, *args, **kwargs): # real signature unknown
""" Update a set with the intersection of itself and another. """
pass
def isdisjoint(self, *args, **kwargs): # real signature unknown
""" Return True if two sets have a null intersection. """
pass
def issubset(self, *args, **kwargs): # real signature unknown
""" Report whether another set contains this set.
相当于 s1 <=s2
"""
pass
def issuperset(self, *args, **kwargs): # real signature unknown
""" Report whether this set contains another set.
相当于 s1 >=s2
"""
pass
def pop(self, *args, **kwargs): # real signature unknown
"""
Remove and return an arbitrary set element.
Raises KeyError if the set is empty.
"""
pass
def remove(self, *args, **kwargs): # real signature unknown
"""
Remove an element from a set; it must be a member.
If the element is not a member, raise a KeyError.
"""
pass
def symmetric_difference(self, *args, **kwargs): # real signature unknown
"""
Return the symmetric difference of two sets as a new set.
相当于 s1^s2 对称差集
(i.e. all elements that are in exactly one of the sets.)
"""
pass
def symmetric_difference_update(self, *args, **kwargs): # real signature unknown
""" Update a set with the symmetric difference of itself and another. """
pass
def union(self, *args, **kwargs): # real signature unknown
"""
并集 相当于s1|s2
Return the union of sets as a new set.
(i.e. all elements that are in either set.)
"""
pass
def update(self, *args, **kwargs): # real signature unknown
""" Update a set with the union of itself and others. """
pass