python字典的4种遍历：键，值，项，键值对

一、遍历字典：键，值，项，键值对

dict={"name":"lily","age":18}
#1.遍历字典的键key:
for key in dict.keys():
    print(key)
#2.遍历字典的值value:
for value in dict.values():
    print(value)
#3.遍历字典的键和值(以元组的格式返回):
for item in dict.items():
    print(item)
#4.遍历字典的键和值:
for key,value in dict.items():
    print(key,value)

二、字典的其他操作
1、判断一个键是否存在于字典中用“in”或“not in”

if "name" in dict:
    print(dict["name"])

2、字典的标准操作：
-, <, >, <=, >=, == ,!=, and ,or ,not

dict={"name":"lily","age":18}
dict0={"name":"lily","age":10}
print(dict==dict0)

3、字典不支持+ ， 重复操作*