1. 增加：字典[key]=value(不存在的key和value)

info={

'stu1101':'TengLan',

'stu1102':'LuoZe',

'stu1103':'XiaoZe'

}

info['stu1104']='crystal'

print(info) #输出结果：{'stu1101': 'TengLan', 'stu1102': 'LuoZe', 'stu1103': 'XiaoZe', 'stu1104': 'crystal'}

2. 修改：字典[key]=value(已存在的key，修改对应value)

info={

'stu1101':'TengLan',

'stu1102':'LuoZe',

'stu1103':'XiaoZe'

}

info['stu1101']='crystal'

print(info) #输出结果：{'stu1101': 'crystal', 'stu1102': 'LuoZe', 'stu1103': 'XiaoZe'}

3. 删除

a. 字典.pop(key)

info={

'stu1101':'TengLan',

'stu1102':'LuoZe',

'stu1103':'XiaoZe'

}

info.pop("stu1101")

print(info) #{'stu1102': 'LuoZe', 'stu1103': 'XiaoZe'}

b. del 字典[key]

info={

'stu1101':'TengLan',

'stu1102':'LuoZe',

'stu1103':'XiaoZe'

}

del info['stu1101']

print(info)

4. 查找

a. in：如果key存在，返回true；反之返回false

info={

'stu1101':'TengLan',

'stu1102':'LuoZe',

'stu1103':'XiaoZe'

}

print("stu1101" in info) #输出结果：True

b.get：通过key获取到value，如果不存在返回None

info={

'stu1101':'TengLan',

'stu1102':'LuoZe',

'stu1103':'XiaoZe'

}

print(info.get("stu1101")) #输出结果：TengLan

c. 字典[key]：如果key存在，返回value；反之则报错

info={

'stu1101':'TengLan',

'stu1102':'LuoZe',

'stu1103':'XiaoZe'

}

print(info["stu1104"])

#输出结果：KeyError: 'stu1104'

5. 多级字典嵌套操作

av_catalog = {

"Europe":{

"Germany":["地域广","文化浓郁"],

"United Kingdom":["历史古国","高校多"],

"Italy":["异域风情","人美"],

"Belgium":["时装","文化"]

},

"Japan":{

"tokyo":["美食","旅游"]

},

"China":{

"Beijing":["国都","历史悠久"]

}

}

av_catalog["China"]["Beijing"][1]="文明之源"

print(av_catalog) #输出结果：{'Europe': {'Germany': ['地域广', '文化浓郁'], 'United Kingdom': ['历史古国', '高校多'], 'Italy': ['异域风情', '人美'], 'Belgium': ['时装', '文化']}, 'Japan': {'tokyo': ['美食', '旅游']}, 'China': {'Beijing': ['国都', '文明之源']}}

6. setdefault ：创建新的key-value

av_catalog = {

"Europe":{

"Germany":["地域广","文化浓郁"],

"United Kingdom":["历史古国","高校多"],

"Italy":["异域风情","人美"],

"Belgium":["时装","文化"]

},

"Japan":{

"tokyo":["美食","旅游"]

},

"China":{

"Beijing":["国都","历史悠久"]

}

}

av_catalog.setdefault("Taiwan",{"travel":[1,2]})

print(av_catalog)

#输出结果：{'Europe': {'Germany': ['地域广', '文化浓郁'], 'United Kingdom': ['历史古国', '高校多'], 'Italy': ['异域风情', '人美'], 'Belgium': ['时装', '文化']}, 'Japan': {'tokyo': ['美食', '旅游']}, 'China': {'Beijing': ['国都', '历史悠久']}, 'Taiwan': {'travel': [1, 2]}}

7. update：两个字典合并，有交叉合并，如没有交叉就更新

info={

'stu1101':'TengLan',

'stu1102':'LuoZe',

'stu1103':'XiaoZe'

}

b = {

'stu1101':"crystal",

1:3,

2:5

}

info.update(b)

print(info) #输出结果：{'stu1101': 'crystal', 'stu1102': 'LuoZe', 'stu1103': 'XiaoZe', 1: 3, 2: 5}

8. fromkeys：初始化一个新的字典

info={

'stu1101':'TengLan',

'stu1102':'LuoZe',

'stu1103':'XiaoZe'

}

b = {

'stu1101':"crystal",

1:3,

2:5

}

c = info.fromkeys([6,7,8],"test")

print(c) #输出结果：{6: 'test', 7: 'test', 8: 'test'}

9. items：把字典转换成列表

info={

'stu1101':'TengLan',

'stu1102':'LuoZe',

'stu1103':'XiaoZe'

}

print(info.items())

#输出结果：dict_items([('stu1101', 'TengLan'), ('stu1102', 'LuoZe'), ('stu1103', 'XiaoZe')])

10. 字典循环

info={

'stu1101':'TengLan',

'stu1102':'LuoZe',

'stu1103':'XiaoZe'

}

for i in info: #此方式循环高效

print(i,info[i])

for k,v in info.items(): #此方式不适合数据量较大的情况

print(k,v)

#输出结果：

stu1101 TengLan

stu1102 LuoZe

stu1103 XiaoZe

stu1101 TengLan

stu1102 LuoZe

stu1103 XiaoZe