Python之set

set

set集合，是一个无序且不重复的元素集合

• set的优势

set 的访问数度快

set 原生解决数据重复问题

# 数据库中原有
old_dict = {
"#1":{ 'hostname':'c1', 'cpu_count': 2, 'mem_capicity': 80 },
"#2":{ 'hostname':'c1', 'cpu_count': 2, 'mem_capicity': 80 },
"#3":{ 'hostname':'c1', 'cpu_count': 2, 'mem_capicity': 80 }
}# cmdb 新汇报的数据
new_dict = {
"#1":{ 'hostname':'c1', 'cpu_count': 2, 'mem_capicity': 800 },
"#3":{ 'hostname':'c1', 'cpu_count': 2, 'mem_capicity': 80 },
"#4":{ 'hostname':'c2', 'cpu_count': 2, 'mem_capicity': 80 }
}s1=set()
for i in old_dict.keys():
s1.add(i)
print(s1)s2=set()
for j in new_dict.keys():
s2.add(j)
print(s2)s3=s2.difference(s1)
print(s3)for n in s3:
s=new_dict.get(n) old_dict.update({n:s})print(old_dict)

Help on set object:
class set(object)
| set() -> new empty set object
| set(iterable) -> new set object
|
| Build an unordered collection of unique elements.
|
| Methods defined here:
|
| __and__(self, value, /)
| Return self&value.
|
| __contains__(...)
| x.__contains__(y) <==> y in x.
|
| __eq__(self, value, /)
| Return self==value.
|
| __ge__(self, value, /)
| Return self>=value.
|
| __getattribute__(self, name, /)
| Return getattr(self, name).
|
| __gt__(self, value, /)
| Return self>value.
|
| __iand__(self, value, /)
| Return self&=value.
|
| __init__(self, /, *args, **kwargs)
| Initialize self. See help(type(self)) for accurate signature.
|
| __ior__(self, value, /)
| Return self|=value.
|
| __isub__(self, value, /)
| Return self-=value.
|
| __iter__(self, /)
| Implement iter(self).
|
| __ixor__(self, value, /)
| Return self^=value.
|
| __le__(self, value, /)
| Return self<=value.
|
| __len__(self, /)
| Return len(self).
|
| __lt__(self, value, /)
| Return self<value.
|
| __ne__(self, value, /)
| Return self!=value.
|
| __new__(*args, **kwargs) from builtins.type
| Create and return a new object. See help(type) for accurate signature.
|
| __or__(self, value, /)
| Return self|value.
|
| __rand__(self, value, /)
| Return value&self.
|
| __reduce__(...)
| Return state information for pickling.
|
| __repr__(self, /)
| Return repr(self).
|
| __ror__(self, value, /)
| Return value|self.
|
| __rsub__(self, value, /)
| Return value-self.
|
| __rxor__(self, value, /)
| Return value^self.
|
| __sizeof__(...)
| S.__sizeof__() -> size of S in memory, in bytes
|
| __sub__(self, value, /)
| Return self-value.
|
| __xor__(self, value, /)
| Return self^value.
|
| add(...)
| Add an element to a set.
|
| This has no effect if the element is already present. '''向set里面添加元素，若为重复元素则不会添加''' |
| clear(...)
| Remove all elements from this set. '''清空set里面的所有元素''' |
| copy(...)
| Return a shallow copy of a set.
'''浅拷贝''' |
| difference(...)
| Return the difference of two or more sets as a new set.
|
| (i.e. all elements that are in this set but not the others.) '''对比两个或多个set，将不相同的元素放到新的set当中, 例：A、B两个集合对比，将A中存在B中不存在的元素返回到一个新的集合中
>>> s1={1,2,3,4}
>>> s2={1,2}
>>> s3=s1.difference(s2)
>>> print(s3)
{3, 4}
'''
|
| difference_update(...)
| Remove all elements of another set from this set. '''从当前集合中删除和B中相同的元素. 注：直接修改当前集合
>>> s1={1,2,3,4}
>>> s2={1,2,}
>>> s1.difference_update(s2)
>>> print(s1)
{3, 4} ''' |
| discard(...)
| Remove an element from a set if it is a member.
|
| If the element is not a member, do nothing.'''如果元素属于集合，删除当前元素，如果不属于，不变
>>> s1={1,2,3,4}
>>> s1.discard(9)
>>> print(s1)
{1, 2, 3, 4}
>>> s1.discard(1)
>>> print(s1)
{2, 3, 4}
''' |
| intersection(...)
| Return the intersection of two sets as a new set.
|
| (i.e. all elements that are in both sets.)'''
取两个集合的交集，返回给一个新的集合>>> s1={1,2,3,4}
>>> s2={1,2,5,6}
>>> s3=s1.intersection(s2)
>>> print(s3)
{1, 2}''' |
| intersection_update(...)
| Update a set with the intersection of itself and another.
|
'''
取两个集合的交集，赋值给当前集合
>>> s1={1,2,3,4}
>>> s2={1,2,5,6}
>>> s1.intersection_update(s2)
>>> print(s1)
{1, 2}
''' | isdisjoint(...)
| Return True if two sets have a null intersection.
'''
判断两个集合是否有交集，如果有返回False，没有则返回Ture
>>> s1={1,2,3,4}
>>> s2={1,2,5,6}
>>> s3={9,10}
>>> s1.isdisjoint(s2)
False
>>> s1.isdisjoint(s3)
True
'''
|
| issubset(...)
| Report whether another set contains this set.
'''
判断前者是不是后面集合的子集，是：Tute，否：False
>>> s1={1,2,3,4}
>>> s2={1,2,3,4,5,6,7}
>>> s3={1,2}
>>> s1.issubset(s2)
True
>>> s1.issubset(s3)
False
'''
|
| issuperset(...)
| Report whether this set contains another set.
'''
判断前者是否是后者的父集，是：Tute，否：False
>>> s1={1,2,3,4}
>>> s2={1,2,3,4,5,6,7}
>>> s3={1,2}
>>> s1.issuperset(s2)
False
>>> s1.issuperset(s3)
True
'''
|
| pop(...)
| Remove and return an arbitrary set element.
| Raises KeyError if the set is empty.
'''
删除集合中的元素，并返回被删除的元素（随机删除？）
'''
|
| remove(...)
| Remove an element from a set; it must be a member.
|
| If the element is not a member, raise a KeyError.'''
删除指定的一个元素，如果不存在，报KeyError错误
'''
|
| symmetric_difference(...)
| Return the symmetric difference of two sets as a new set.
|
| (i.e. all elements that are in exactly one of the sets.)
'''
差集：将两个集合中不相同的元素返回到一个新的集合中
>>> s1={1,2,3,4}
>>> s2={1,2,3,4,5,6,7}
>>> s3=s1.symmetric_difference(s2)
>>> print(s3)
{5, 6, 7}
'''
|
| symmetric_difference_update(...)
| Update a set with the symmetric difference of itself and another.
'''
差集：将两个集合中不同的元素赋值给当前集合
>>> s1={1,2,3,4}
>>> s2={1,2,3,4,5,6,7}
>>> s1.symmetric_difference_update(s2)
>>> print(s1)
{5, 6, 7}
'''
|
| union(...)
| Return the union of sets as a new set.
|
| (i.e. all elements that are in either set.)
'''
并集：取两个集合的并集复制给新的集合
>>> s1={1,2,3,4}
>>> s2={4,5,6,7}
>>> s3=s1.union(s2)
>>> print(s3)
{1, 2, 3, 4, 5, 6, 7}
'''
|
| update(...)
| Update a set with the union of itself and others.
'''
更新：将后面的集合的元素添加到当前集合
>>> s1={1,2,3,4,"yangge"}
>>> s2={1,2,3,4,5,6,7}
>>> s1.update(s2)
>>> print(s1)
{1, 2, 3, 4, 5, 6, 7, 'yangge'}
''' |
| ----------------------------------------------------------------------
| Data and other attributes defined here:
|
| __hash__ = None
None