字典：python中唯一一个映射数据类型
按照可变与不可变分类：
可变：list dict set
不可变： int str boor tuple
key ： value
key：是唯一的，且不可变的数据类型
value：任意数据类型
在3.5版本之前，字典是无序的，3.6是有序的
增：
#① dic = {"name":"刘林","age":23,"sex":"man"} dic["name1"]= "liulin" print(dic) #输出：{'name': '刘林', 'age': 23, 'sex': 'man', 'name1': 'liulin'}
#② dic = {"name":"刘林","age":23,"sex":"man"} dic.setdefault("name1","liulin") print(dic) #输出：{'name': '刘林', 'age': 23, 'sex': 'man', 'name1': 'liulin'}
删：
#①按key删，有返回值 dic = {"name":"刘林","age":23,"sex":"man"} dic.pop("name","没有此项内容") print(dic) #如果name不在字典里，并且不写”没有此项内容“，则会报错
#②clear 清空 dic = {"name":"刘林","age":23,"sex":"man"} dic.clear() print(dic) #输出：{}
#③del #删除字典 dic = {"name":"刘林","age":23,"sex":"man"} del dic #删除键值对 dic = {"name":"刘林","age":23,"sex":"man"} del dic["name"] print(dic) #输出：{'age': 23, 'sex': 'man'} dic = {"name":"刘林","age":23,"sex":"man"} dic.popitem() print(dic) #随机删除，但是python3.5之后有序，所以默认删除最后一个，有返回值 #输出：{'name': '刘林', 'age': 23}
改 ：dic["key"] = value key是字典里有的
#① dic = {"name":"刘林","age":23,"sex":"man"} dic["name"] = "liulin" print(dic) #输出：{'name': 'liulin', 'age': 23, 'sex': 'man'} #②update dic = {"name":"刘林","age":23,"sex":"man"} dic2 = {"name":"liulin","hobby":"basketball"} dic.update(dic2) print(dic) #将dic的键值对进行覆盖并添加到dic #输出：{'name': 'liulin', 'age': 23, 'sex': 'man', 'hobby': 'basketball'}
查
dic = {"name":"刘林","age":23,"sex":"man"}
print(dic["name"])
#没有返回值，如果没有key，报错
#输出：刘林
#get 有返回值，没有key 返回nane
dic = {"name":"刘林","age":23,"sex":"man"}
print(dic.get("name"，”返回值“))
#输出：刘林
分别赋值：a,b = 1,2
a=1 b=2
罗列所有key：
dic = {"name":"刘林","age":23,"sex":"man"}
keys = dic.keys()
print(keys)
#输出：dict_keys(['name', 'age', 'sex'])
罗列所有值：
dic = {"name":"刘林","age":23,"sex":"man"}
values = dic.values()
print(values)
#输出：dict_values(['刘林', 23, 'man'])
罗列所有键值对：
dic = {"name":"刘林","age":23,"sex":"man"}
items = dic.items()
print(items)
#输出：dict_items([('name', '刘林'), ('age', 23), ('sex', 'man')])
循环：
dic = {"name":"刘林","age":23,"sex":"man"}
for i in dic:
print(i) #输出key
for k in dic.keys():
print(k) #输出key
for v in dic.values():
print(v) #输出value
items = dic.items()
print(items) #输出：dict_items([('name', '刘林'), ('age', 23), ('sex', 'man')])
字典嵌套
dic = { 'name':'金鑫', 'name_list':[1,2,3,'李杰'], 1:{ 'python10':['小黑','萌哥'], '老男孩':{'name':'oldboy','age':56} } } #1,[1,2,3,'李杰']追加'wusir' #2, ['小黑','萌哥'] 小黑 萌哥中间 插入一个花哥 #3, {'name':'oldboy','age':56} 添加一个键值对,hobby:男人 l = [1,2,3] # print(l.append('wusir')) # print(l) # dic['name_list'].append('wusir') # print(dic) # l = dic[1]['python10'] # l.insert(1,'花哥') # print(dic) # dic1 = dic[1] # dic2 = dic1['老男孩'] # dic2['hobby'] = '男人' # dic[1]['老男孩']['hobby'] = 'man' # print(dic)