【python之路11】集合数据类型（set）

集合数据类型（set）:集合是不重复的无需序列

1、集合数据类型的创建

a = {11,22,33}
#或
a = set() #创建空集合，不能用a={},这样创建的是字典类型

2、集合转换（将可迭代的转换为集合）

li = [11,22,33,11]
se = set(li)
print(se)  #返回{33, 11, 22}

3、set方法总结se1 = {11,22}se2 = {22,33,44}se3 = {22,33}

se1.add(33)  #se1返回{33, 11, 22}，增加元素
se1.clear() #se1返回set()，清空所有元素
se_new = se1.copy() #新集合se_new 返回{11, 22}，浅拷贝

se_new  = se1.difference(se2) #返回新集合，se1中存在但se2中不存在的元素
se1.difference_update(se2) #se1更新为se1中存在且se2中不存在的元素,se1={11}

se_new = se1.symmetric_difference(se2) #对称不同，实际返回两个集合并集去掉两个集合中交集元素，se_new={33, 11, 44}，
实际上是se1中有se2中没有 并集于 se2中有se1中没有的
se1.symmetric_difference_update(se2) #更新对称不同，se1更新为两个集合并集去掉两个集合中交集元素，se1={33, 11, 44}，
实际上是se1中有se2中没有 并集于 se2中有se1中没有的
se_new = se1.intersection(se2) #返回一个新的集合，se_new为两个集合的交集，{22}
se1.intersection_update(se2) #更新se1为se1和se2的交集，se1={22}
se_new = se1.union(se2) #返回新集合，se1与se2的并集
se1.update(se2) #se1更新为，se1与se3的并集，se1={33, 11, 44, 22}
se1.discard(11) #se1={22},抛弃一个元素，如果参数中的元素不存在，不报错
element = se1.pop() #删除任意一个元素，并将删除的元素赋值为element,element=11,se1={22},若果是空集合则抛KeyError异常
se1.remove(11) #从se1中移除11元素，se1 = {22},如果参数在set中不存在这个元素则抛出KeyError异常
bol = se1.isdisjoint(se1) #判断se1与se2是否没有交集，如果没有返回True，如果有返回False,bol=False
bol = se3.issubset(se2) #判断se3是否是子集合，se3的元素完全包含在se2内，则返回True
bol = se2.issuperset(se3) #判断se2是否是父集合，se2的元素完全包含se3,则返回True

4、set方法详细代码

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.
		添加一个元素到集合
		这没有影响如果元素已经存在
        """
        pass

    def clear(self, *args, **kwargs): # real signature unknown
        """ Remove all elements from this set.
		从这个集合中移除所有元素"""
        pass

    def copy(self, *args, **kwargs): # real signature unknown
        """ Return a shallow copy of a set.
		返回一个浅拷贝的集合"""
        pass

    def difference(self, *args, **kwargs): # real signature unknown
        """
        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.)
		作为一个新的集合返回两个或多个集合的不同
		（也就是所有元素在这个集合中，但不在另一个集合中）
        """
        pass

    def difference_update(self, *args, **kwargs): # real signature unknown
        """ Remove all elements of another set from this set.
		从这个集合中删除另一个集合的所有元素"""
        pass

    def discard(self, *args, **kwargs): # real signature unknown
        """
        Remove an element from a set if it is a member.

        If the element is not a member, do nothing.
		从一个集合中移除一个元素，如果它是个成员
		如果这个元素不是一个成员，什么也不做
        """
        pass

    def intersection(self, *args, **kwargs): # real signature unknown
        """
        Return the intersection of two sets as a new set.

        (i.e. all elements that are in both sets.)
		作为一个新的集合返回两个集合的交集
		（也就是，所有在两个结合中都有对的元素）
        """
        pass

    def intersection_update(self, *args, **kwargs): # real signature unknown
        """ Update a set with the intersection of itself and another.
		更新一个集合用自己和另一个集合的交集"""
        pass

    def isdisjoint(self, *args, **kwargs): # real signature unknown
        """ Return True if two sets have a null intersection.
		返回True 如果两个集合没有交集"""
        pass

    def issubset(self, *args, **kwargs): # real signature unknown
        """ Report whether another set contains this set.
		报告是否另一个集合包含这个集合
		"""
        pass

    def issuperset(self, *args, **kwargs): # real signature unknown
        """ Report whether this set contains another set.
		报告是否这个集合包含另一个集合"""
        pass

    def pop(self, *args, **kwargs): # real signature unknown
        """
        Remove and return an arbitrary set element.
        Raises KeyError if the set is empty.
		移除并返回任意集合元素
		抛出KeyError 如果集合是空的
        """
        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.
		从集合中移除一个元素；它必须是一个成员。
		如果这个元素不是一个成员，抛出KeyError异常
        """
        pass

    def symmetric_difference(self, *args, **kwargs): # real signature unknown
        """
        Return the symmetric difference of two sets as a new set.

        (i.e. all elements that are in exactly one of the sets.)
		作为一个新的集合返回两个集合的对称不同
		（也就是所有元素正好在众集合中的一个）
		实际上是a集合存在且b集合中不存在的元素，并集于，b集合存在且a集合不存在的元素
        """
        pass

    def symmetric_difference_update(self, *args, **kwargs): # real signature unknown
        """ Update a set with the symmetric difference of itself and another.
		更新一个集合用自己和另一个集合的不同
		"""

        pass

    def union(self, *args, **kwargs): # real signature unknown
        """
        Return the union of sets as a new set.

        (i.e. all elements that are in either set.)
		作为一个新的集合返回集合的并集。
		也就是在这两个集合中的所有元素）
        """
        pass

    def update(self, *args, **kwargs): # real signature unknown
        """ Update a set with the union of itself and others.
		更新一个集合用自己和另一个集合的并集"""
        pass

    def __and__(self, *args, **kwargs): # real signature unknown
        """ Return self&value. """
        pass

    def __contains__(self, y): # real signature unknown; restored from __doc__
        """ x.__contains__(y) <==> y in x. """
        pass

    def __eq__(self, *args, **kwargs): # real signature unknown
        """ Return self==value. """
        pass

    def __getattribute__(self, *args, **kwargs): # real signature unknown
        """ Return getattr(self, name). """
        pass

    def __ge__(self, *args, **kwargs): # real signature unknown
        """ Return self>=value. """
        pass

    def __gt__(self, *args, **kwargs): # real signature unknown
        """ Return self>value. """
        pass

    def __iand__(self, *args, **kwargs): # real signature unknown
        """ Return self&=value. """
        pass

    def __init__(self, seq=()): # known special case of set.__init__
        """
        set() -> new empty set object
        set(iterable) -> new set object

        Build an unordered collection of unique elements.
        # (copied from class doc)
        """
        pass

    def __ior__(self, *args, **kwargs): # real signature unknown
        """ Return self|=value. """
        pass

    def __isub__(self, *args, **kwargs): # real signature unknown
        """ Return self-=value. """
        pass

    def __iter__(self, *args, **kwargs): # real signature unknown
        """ Implement iter(self). """
        pass

    def __ixor__(self, *args, **kwargs): # real signature unknown
        """ Return self^=value. """
        pass

    def __len__(self, *args, **kwargs): # real signature unknown
        """ Return len(self). """
        pass

    def __le__(self, *args, **kwargs): # real signature unknown
        """ Return self<=value. """
        pass

    def __lt__(self, *args, **kwargs): # real signature unknown
        """ Return self<value. """
        pass

    @staticmethod # known case of __new__
    def __new__(*args, **kwargs): # real signature unknown
        """ Create and return a new object.  See help(type) for accurate signature. """
        pass

    def __ne__(self, *args, **kwargs): # real signature unknown
        """ Return self!=value. """
        pass

    def __or__(self, *args, **kwargs): # real signature unknown
        """ Return self|value. """
        pass

    def __rand__(self, *args, **kwargs): # real signature unknown
        """ Return value&self. """
        pass

    def __reduce__(self, *args, **kwargs): # real signature unknown
        """ Return state information for pickling. """
        pass

    def __repr__(self, *args, **kwargs): # real signature unknown
        """ Return repr(self). """
        pass

    def __ror__(self, *args, **kwargs): # real signature unknown
        """ Return value|self. """
        pass

    def __rsub__(self, *args, **kwargs): # real signature unknown
        """ Return value-self. """
        pass

    def __rxor__(self, *args, **kwargs): # real signature unknown
        """ Return value^self. """
        pass

    def __sizeof__(self): # real signature unknown; restored from __doc__
        """ S.__sizeof__() -> size of S in memory, in bytes """
        pass

    def __sub__(self, *args, **kwargs): # real signature unknown
        """ Return self-value. """
        pass

    def __xor__(self, *args, **kwargs): # real signature unknown
        """ Return self^value. """
        pass

    __hash__ = None

5、实例需求

old_dic = {"#1":11,"#2":22,"#3":33}
new_dic = {"#3":44,"#4":55,"#5":66}
需求：
1、old_dic与new_dic如果字典key值相同，则new的值更新到old里面
2、new里面存在old里面不存在，则在old里面添加
3、old中存在new中不存在则在old中删除

old_dic = {"#1":11,"#2":22,"#3":33}
new_dic = {"#3":44,"#4":55,"#5":66}

old_set = set(old_dic.keys()) #key值转换为集合
new_set = set(new_dic.keys())
set_inter = old_set.intersection(new_set)  #old与new交集
for i in set_inter:  #更新old列表
    old_dic[i] = new_dic[i]
set_new_dife = new_set.difference(old_set) #new里面存在，old里面不存在的集合
for i in set_new_dife:
    old_dic[i] = new_dic[i]
set_old_dife = old_set.difference(new_set) #old里面存在，new里面不存在的集合
for i in set_old_dife:
    old_dic.pop(i)
print(old_dic)