Python学习之旅 —— 基础篇（三）set集合、函数、文件操作

class set(object):
    """
     创建set集合
    set() -> new empty set object
     把可迭代的数据类型转换成元组
    set(iterable) -> new set object
    
    Build an unordered collection of unique elements.
    """

>>> s1 = {11, 22, 33}
>>> print(s1,type(s1))
{33, 11, 22} <class ‘set‘>
 
>>> l1 = [2, 3, 4,]
>>> s1 = set(l1)
>>> print(l1,type(l1))
[2, 3, 4] <class ‘list‘>
>>> print(s1,type(s1))
{2, 3, 4} <class ‘set‘>

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    # 向集合中增加元素，如果存在，不做任何操作。
    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

>>> s1 = {11, 22, 33}
>>> s1.add(44)
>>> print(s1)
{33, 11, 44, 22}

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# 清空集合中所有的元素
    def clear(self, *args, **kwargs): # real signature unknown
        """ Remove all elements from this set. """
        pass

>>> s1 = {11, 22, 33}
>>> print(s1)
{33, 11, 22}
>>> s1.clear()
>>> print(s1)
set()

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# 浅复制一个集合 只拷贝第一层
    def copy(self, *args, **kwargs): # real signature unknown
        """ Return a shallow copy of a set. """
        pass
 
    # s1.difference(s2) 找到在s1中有，s2中没有的元素，并保存到一个新的集合
    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.)
        """
        pass

>>> s1 = {11,22,33,}
>>> s2 = {22,33,44,}
>>> s3 = s1.difference(s2)
>>> print("%s \n%s \n%s" % (s1,s2,s3))
{33, 11, 22} 
{33, 44, 22}
{11}

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# s1.difference(s2) 找到在s1中有，s2中没有的元素，把结果更新到s1中
    def difference_update(self, *args, **kwargs): # real signature unknown
        """ Remove all elements of another set from this set. """
        pass

>>> s1 = {11,22,33,}
>>> s2 = {22,33,44,}
>>> s1.difference_update(s2)
>>> print("%s \n%s" % (s1,s2))
{11}
{33, 44, 22}

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# s1.intersection(s2) 找到即在集合s1中，又在集合s2中的元素，并把结果保存到一个新的集合里。
    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.)
        """
        pass

>>> s1 = {11,22,33,}
>>> s2 = {22,33,44,}
>>> s3 = s1.intersection(s2)
>>> print("%s \n%s \n%s" % (s1,s2,s3))
{33, 11, 22} 
{33, 44, 22}
{33, 22}

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# s1.intersection(s2) 找到即在集合s1中，又在集合s2中的元素，并把结果更新到s1中
    def intersection_update(self, *args, **kwargs): # real signature unknown
        """ Update a set with the intersection of itself and another. """
        pass

>>> s1 = {11,22,33,}
>>> s2 = {22,33,44,}
>>> s1.intersection_update(s2)
>>> print("%s \n%s" % (s1,s2))
{33, 22}
{33, 44, 22}

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　　# 判断两个集合是否有交接，没有交集时返回True,有交集时返回False

    def isdisjoint(self, *args, **kwargs): # real signature unknown
        """ Return True if two sets have a null intersection. """
        pass

>>> s1 = {11,22,33,}
>>> s2 = {22,33,44,}
>>> s3 = {1,2,3,}
>>> s1.isdisjoint(s2)
False
>>> s1.isdisjoint(s3)
True

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 # s1.issubset(s2) 判断s1是不是s2的子集

    def issubset(self, *args, **kwargs): # real signature unknown
        """ Report whether another set contains this set. """
        pass

>>> s1 = {11,22,}
>>> s2 = {11,22,33,44,}
>>> s3 = {22,33,}
>>> s1.issubset(s2)
True
>>> s1.issubset(s3)
False

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# s1.issuperset(s2) 判断s1是不是s2的父集
    def issuperset(self, *args, **kwargs): # real signature unknown
        """ Report whether this set contains another set. """
        pass

>>> s1 = {11,22,33,44,55}
>>> s1 = {11,22,33,44,55,}
>>> s2 = {22,33,55,}
>>> s3 = {44,33,66,}
>>> s1.issuperset(s2)
True
>>> s1.issuperset(s3)
False

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# 任意删除并返回一个元素
    def pop(self, *args, **kwargs): # real signature unknown
        """
        Remove and return an arbitrary set element.
        Raises KeyError if the set is empty.
        """
        pass

>>> s1 = {11,22,33,44,55,}
>>> s1.pop()
33

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    # 删除指定的一个元素，这个元素必须在集合中，否则报错。区别于discard()
    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

>>> s1 = {11,22,33,}
>>> s1.remove(11)
>>> print(s1)
{33, 22}
>>> s1.remove(44)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
KeyError: 44

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    # 删除指定的一个元素，如果元素不存在不报错。可以起到判断元素是否在集合中时，代码不报错的作用。
    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.
        """
        pass

>>> s1 = {11,22,33,}
>>> s1.discard(11)
>>> print(s1)
{33, 22}
>>> s1.discard(44)   # 44 不在s1中，操作时不报错
>>> print(s1)
{33, 22}

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# 相当于取两个集合的并集，再把他俩的交集删掉。返回这个新集合。
    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.)
        """
        pass

>>> s1 = {11,22,33,44,}
>>> s2 = {22,44,55,66}
>>> s3 = s1.symmetric_difference(s2)
>>> print("%s \n%s \n%s" % (s1,s2,s3))
{33, 11, 44, 22} 
{66, 44, 22, 55} 
{33, 66, 11, 55}

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    # s1.symmetric_difference_update(s2) 相当于取s1，s2两个集合的并集，再把他俩的交集删掉。结果赋值给s1
    def symmetric_difference_update(self, *args, **kwargs): # real signature unknown
        """ Update a set with the symmetric difference of itself and another. """
        pass

>>> s1 = {11,22,33,44,}
>>> s2 = {22,44,55,66}
>>> s1.symmetric_difference_update(s2)
>>> print("%s \n%s" % (s1,s2))
{33, 66, 11, 55} 
{66, 44, 22, 55}

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    # 取两个集合的并集，结果返回到一个新集合中。
    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.)
        """
        pass

>>> s1 = {11,22,33,44,}
>>> s2 = {22,44,55,66}
>>> s3 = s1.union(s2)
>>> print("%s \n%s \n%s" % (s1,s2,s3))
{33, 11, 44, 22} 
{66, 44, 22, 55}
{33, 66, 11, 44, 22, 55}

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# s1.update(s2) 去两个集合的并集，将结果赋值给s1
    def update(self, *args, **kwargs): # real signature unknown
        """ Update a set with the union of itself and others. """
        pass

>>> s1 = {11,22,33,44,}
>>> s2 = {22,44,55,66}
>>> s1.update(s2)
>>> print("%s \n%s" % (s1,s2))
{33, 66, 11, 44, 22, 55}
{66, 44, 22, 55}

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