Python_Day_04 set方法总结

set（集合）

• 直接创建一个空集合

set_empty = set()
print(set_empty) # set()

• 根据参数创建

# 根据参数
set_argument = set(42,‘345‘,‘ry‘)
print(set_argument) # 这样会报错,因为set只允许有一个参数

• 根据列表来创建

set_list = set([11,11,‘45‘,‘11‘,‘ee‘])
print(set_list) # {11, ‘ee‘, ‘45‘, ‘11‘} 会自动删除重复对象

• 根据元组来创建

set_tuple = set((11,11,‘45‘,‘11‘,‘ee‘,))
print(set_tuple) # {‘ee‘, 11, ‘45‘, ‘11‘} 同样会自动删除重复对象

• 根据字典来创建

set_dict = set({‘k1‘:‘v1‘,‘k2‘:2,‘k3‘:‘v3‘,‘k1‘:‘v4‘})
print(set_dict) # {‘k3‘, ‘k1‘, ‘k2‘} 只会存储key值,且不会重复

• 字符串创建

set_str = set(‘Hello Python‘)
print(set_str) # {‘y‘, ‘o‘, ‘n‘, ‘ ‘, ‘P‘, ‘t‘, ‘h‘, ‘H‘, ‘e‘, ‘l‘} 同样会删除字符串中重复的字符

• add(self, *args, **kwargs) 添加一个新的元素到集合中,如果添加的元素在集合中已经存在就不会有任何操作

set_init = set([11,11,‘45‘,‘11‘,‘ee‘])
set_init.add(‘Hello‘)
print(set_init) # {‘Hello‘, 11, ‘ee‘, ‘11‘, ‘45‘}

set_init_str = set(‘Python‘)
set_init_str.add(‘Hello,World‘)
print(set_init_str) # {‘Hello,World‘, ‘o‘, ‘P‘, ‘t‘, ‘n‘, ‘y‘, ‘h‘}

• clear(self, *args, **kwargs) 清除集合中元素,可以传参数

set_init_clear = set([11,11,‘45‘,‘11‘,‘ee‘])
set_init_clear.clear()
print(set_init_clear) # set()

• copy(self, *args, **kwargs)  浅拷贝,会返回一个新的集合

set_init_copy = set([11,11,‘45‘,‘11‘,‘ee‘])
set_receive_copy = set_init_copy.copy()
print(set_receive_copy) # {‘ee‘, 11, ‘45‘, ‘11‘}

• difference(self, *args, **kwargs)  比较两个集合类的不同,返回的是被主动比较的那个集合与比较集合的交集之外的子集(数学上叫啥给忘了)

set_init_dif1 = set([11,22,33,44])
set_init_dif2 = set([33,44,55,66])
set_init_rece1 = set_init_dif1.difference(set_init_dif2)
print(set_init_rece1) # {11, 22}
set_init_rece2 = set_init_dif2.difference(set_init_dif1)
print(set_init_rece2) # {66, 55}

• difference_update(self, *args, **kwargs)  删除两个集合的交际

set_init_upd1 = set([11,22,33,44])
set_init_upd2 = set([33,44,55,66])
set_init_upd1.difference_update(set_init_upd2)
print(set_init_upd1) # {22, 11}

set_init_upd3 = set([11,22,33,44])
set_init_upd4 = set([33,44,55,66])
set_init_upd4.difference_update(set_init_upd3)
print(set_init_upd4) # {66, 55}

• discard(self, *args, **kwargs)  删除集合中存在的元素,如果不存在就什么也不做

set_init_dis = set([11,22,33,44,55])
set_init_dis.discard(11)
print(set_init_dis) # {33, 44, 22, 55} 只能删除一个

• intersection(self, *args, **kwargs)  返回两个集合中的交集

set_init_inter1 = set([11,22,33,44])
set_init_inter2 = set([33,44,55,66])
set_rece_inter1 = set_init_inter1.intersection(set_init_inter2)
print(set_rece_inter1) # {33, 44}

• intersection_update(self, *args, **kwargs)  取出两个集合的交集,更新一个集合

set_inter_upd1 = set([111,222,333,444])
set_inter_upd2 = set([333,444,55,66])
set_inter_upd1.intersection_update(set_inter_upd2)
print(set_inter_upd1) # {444, 333}

• isdisjoint(self, *args, **kwargs)  判断两个集合是否有交集,如果有就返回False,如果没有就返回Ture

set_isdis1 = set([111,222,333,444])
set_isdis2 = set([222,333])
set_receive_isdis1 = set_isdis1.isdisjoint(set_isdis2)
print(set_receive_isdis1) # False 说明有交集

• issubset(self, *args, **kwargs)  判断A集合是否是B集合的子集

set_issub1 = set([111,222,333,444])
set_issub2 = set([222,333])
set_receive_issub1 = set_issub1.issubset(set_issub2)
print(set_receive_issub1) # False 说明set_issub1不是set_issub2的子集
set_receive_issub2 = set_issub2.issubset(set_issub1)
print(set_receive_issub2) # True 说明set_issub2是set_issub1的子集

• issuperset(self, *args, **kwargs)  判断A集合是否是B集合的父类,就是A集合是否包含B集合.结果跟  issubset(self, *args, **kwargs) 相反
• pop(self, *args, **kwargs)  移除元素,同时可以定义一个变量来接收移除的元素,如果集合为空会报错

set_pop = set([111,222,333,444,232])
set_receive_pop = set_pop.pop()
print(set_pop) # {444, 333, 222, 111}
print(set_receive_pop) # 232

• remove(self, *args, **kwargs)  删除元素

set_remove = set([111,222,333,444,232])
set_remove.remove(111)
print(set_remove) # {232, 444, 333, 222}

• symmetric_difference(self, *args, **kwargs)  取出两个差,更新到一个集合中,如果同时删除A,B两集合中相同元素删除.

set_sym1 = set([1,2,3,4,5])
set_sym2 = set([2,3,4,5,6,])
set_receive_sym1 = set_sym1.symmetric_difference(set_sym2)
print(set_receive_sym1) # {1, 6}

set_sym3 = set([1,2,3,4,5])
set_sym4 = set([6,])
set_receive_sym2 = set_sym3.symmetric_difference(set_sym4)
print(set_receive_sym2) # {1, 2, 3, 4, 5, 6}

• symmetric_difference_update(self, *args, **kwargs)  将B集合中有,而A集合中没有的更新到A集合中

set_sym_up1 = set([1,2,3,4,5])
set_sym_up2 = set([2,3,4,5,6,])
set_sym_up1.symmetric_difference_update(set_sym_up2)
print(set_sym_up1) # {1, 6}

set_sym_up3 = set([1,2,3,4,5])
set_sym_up4 = set([6,])
set_sym_up3.symmetric_difference_update(set_sym_up4)
print(set_sym_up3) # {1, 2, 3, 4, 5, 6}

• union(self, *args, **kwargs)  返回A集合和B集合的并集

set_un1= set([11,22,33,44])
set_un2 = set([22,33,44,55])
set_rec_un = set_un1.union(set_un2)
print(set_rec_un) # {33, 11, 44, 22, 55}

• update(self, *args, **kwargs)  A和B的并集,并返回A

set_un_up1 = set([111,222,333,444])
set_un_up2 = set([222,333,444,555])
set_un_up1.update(set_un_up2)
print(set_un_up1) # {555, 333, 111, 444, 222}