from collections.abc import Mapping,MutableMapping

#dict属于mapping类型

a = {}   #字典a不是继承MutableMapping，而是实现了MutableMapping的魔法函数

print(isinstance(a,MutableMapping)) #True

a = {"lishuntao":{"company":"hut"},

     "lishuntao1":{"company":"hut1"}

     }

#clear

# a.clear()

# print(a) #{}

#copy,返回浅拷贝

# new_dict = a.copy()

# new_dict["lishuntao"]["company"] = "HUT"  #new_dict拷贝出"lishuntao"与"lishuntao1"这是浅拷贝，

# # 第二层的dict也就是数据结构没有被拷贝出来，因此值会变动。

# print(new_dict) #{'lishuntao': {'company': 'HUT'}, 'lishuntao1': {'company': 'hut1'}}

# print(a) #{'lishuntao': {'company': 'HUT'}, 'lishuntao1': {'company': 'hut1'}}

#深拷贝

import copy

new_dict = copy.deepcopy(a)

new_dict["lishuntao"]["company"] = "HUT"

print(a) #{'lishuntao': {'company': 'hut'}, 'lishuntao1': {'company': 'hut1'}}

print(new_dict) #{'lishuntao': {'company': 'HUT'}, 'lishuntao1': {'company': 'hut1'}}

#fromkeys 将可迭代的对象转换为dict

new_list = ["li","li1","li2"]

new_dict = dict.fromkeys(new_list,{"company":"hut"})

print(new_dict) #{'li': {'company': 'hut'}, 'li1': {'company': 'hut'}, 'li2': {'company': 'hut'}}

#get #如果没有这个键不会抛异常

value = a.get("lishuntao111",{})

print(value) #{}

#items()

for key,value in a.items():

    print(key,value)    #lishuntao {'company': 'hut'},lishuntao1 {'company': 'hut1'}

#setdefault

new_dict = a.setdefault("litao","hugongda")

print(new_dict) #hugongda

print(a) #{'lishuntao': {'company': 'hut'}, 'lishuntao1': {'company': 'hut1'}, 'litao': 'hugongda'}

#update #可迭代的对象

#a.update([("lishun","tao"),("li110","hu")])

a.update(lishun='tao',li110="hu")#一样的效果

# #不建议继承dict和list

# class Mydict(dict):

#     def __setitem__(self, key, value):

#         super(Mydict, self).__setitem__(key,value*2)

#

# my_dict = Mydict(one=1)

# print(my_dict) #{'one': 1}

# my_dict["one"] = 1 #{'one': 2}

# print(my_dict)

# """

# 在某些情况下，用C语言写出来的python内置类型，它不会调用__setitem__方法

# 因此我们想要继承dict的话，就去继承UserDict（例如下面）

# """

from collections import UserDict

#

#

# class Mydict1(UserDict):

#     def __setitem__(self, key, value):

#         super(Mydict1, self).__setitem__(key,value*2)

#

# my_dict = Mydict1(one=1)

# print(my_dict) #{'one': 2}

# my_dict["one"] = 1 #{'one': 2}

# print(my_dict)

from collections import defaultdict

"""

defaultdict重写了__missing__方法

"""

my_dict = defaultdict(dict)

my_value = my_dict["lishun"] #按照正常情况会报错误

print(my_value)  #{}

my_dict1 = {}

my_value1 = my_dict1["lishun"]

print(my_value1) #KeyError: 'lishun'

#set 集合  frozenset 不可变集合   无序、不重复

s = set("abcde")

s.add("u")

print(s)#{'b', 'a', 'e', 'd', 'c', 'u'}

s2 = frozenset("abcdef") #frozenset 可以作为dict的key

print(s2)  #frozenset({'b', 'f', 'a', 'e', 'd', 'c'}) #不能修改

#difference

anoth_set = set("cdefgh")

res = s.difference(anoth_set)

print(res)  #{'a', 'b', 'u'}

#集合运算 交 并 差集

res  = s - anoth_set

res1 = s & anoth_set #交

res2 = s | anoth_set #并

#set性能高  #实现__contains__魔法函数就可以做if判断