字典的基本用法

user_info={"name":"wang","age":"26","gender":"man"}
#我们用键值对来表示
key：name,age,gender
value:wang,26,man

 

#清空字典

user_info={"name":"wang","age":"26","gender":"man"}
user_info.clear()
print(user_info)
#输出：{}

 

# 通过键获得值

user_info={"name":"wang","age":"26","gender":"man"}
str1= user_info.get("name")
print(str1)
#输出:wang

 

# 获得字典里面内容以列表表示

user_info={"name":"wang","age":"26","gender":"man"}
str1= user_info.items()
print(str1)
#输出：dict_items([('name', 'wang'), ('gender', 'man'), ('age', '26')])

 

 

#获得字典里面所有键值 列表表示

user_info={"name":"wang","age":"26","gender":"man"}
str1= user_info.keys()
print(str1)
#输出：dict_keys(['name', 'gender', 'age'])

 

#获得字典里面所有的键值表示

user_info={"name":"wang","age":"26","gender":"man"}
str1= user_info.values()
print(str1)
#输出：dict_values(['26', 'wang', 'man'])

#增加

user_info={"name":"wang","age":"26","gender":"man"}
user_info["salary"]="2000"
print(user_info)
#{'name': 'wang', 'age': '26', 'gender': 'man', 'salary': '2000'}

 

 

 

 

 

#查找

user_info={"name":"wang","age":"26","gender":"man"}
print("age" in  user_info.keys(）)
#输出：True

#删除

user_info={"name":"wang","age":"26","gender":"man"}
ret=user_info.pop("name")
print(ret)
#返回 wang  有放回值

 

dic={"k1":11,"k2":22,"k3":33}
del dic["k2"]
print(dic)
#输出{'k1': 11, 'k3': 33} 无返回值

#如果删除的key不在字典中那么就会报错
dic={"k1":11,"k2":22,"k3":33}
del dic["k5"]
print(dic)
#输出：KeyError: 'k5'

 

update(self, E=None, **F): 更新字典（个人感觉没什么卵用）

dic={"k1":11,"k2":22,"k3":33}
dic.update({"k1":11,"k2":22,"k3":33,"k4":55})
print(dic)
#输出：{'k2': 22, 'k4': 55, 'k3': 33, 'k1': 11}