Python 字典

#author F

#字典基本操作
info = {
    'stu1101':'Mr F',
    'stu1102':'miss l00 ',
    'stu1103':'dr key'
}
print(info) #字典是无序的
#查询
print(info["stu1102"])
#修改
info["stu1101"] = "aobama"
print(info)
#增加
info["stu1104"] = "Cort"
print(info)
#删除
del info["stu1103"] #删除指定
info.pop("stu1102") #删除指定
info.popitem() #随便删除
#查询
dist = {
    "1":"asd1asd",
    "2":"asda2sd",
    "3":"asdas3d",
    "4":"asd4asd",
    "5":"as5dasd",
    "6":"asd6asd",
    "7":"asda7sd",
    "8":"asdas8d"
}
# info['9'] #字典中不存在时报错 KeyError错误
print(dist.get("3")) #有就返回 没有返回null
print('5' in dist)  #查找字典中是否存在某个key

#多级字典嵌套及操作

category = {
    "oumei":{
        "yourporn":["henduomianfei", "zhiliangyiban"],
        "pornhub":["henduomianfei", "zhiliangjiaogao"],
        "letmedothistoyou":["duoshizipai", "ziyuanbuduo"],
        "x-art":["zhilianghengao", "quanbushoufei"]
    },
    "rihan":{
        "tokyohot":["buzhidao","nizijikan"]
    },
    "dalu":{
        "1024":["quanbumianfei","suduman"]
    }
}
category["dalu"]["1024"] = "keyizaiguoneizuojingxiang"
category.setdefault("taiwan", {"www.baidu.com":[1,2]}) #先去字典中找 找到则返回 找不到则创建新值

print(category)

#
b = {
    "teacher1": "1cool",
    "stu1102": "2cool",
    "teacher3": "3cool"
}
info.update(b) #字典合并 有则改 无则加
print(info)

print(info.items())  #字典转成列表

c = dict.fromkeys([6, 7, 8], "test") #初始化一个新的字典
print(c) #{6: 'test', 7: 'test', 8: 'test'}
#坑
c = dict.fromkeys([6, 7, 8], [1, {"name":"aobama"}, 444]) #fromkeys填入的是内存地址 所以导致全部修改
c[7][1]["name"] = "changed_name"
print(c) #{6: [1, {'name': 'changed_name'}, 444], 7: [1, {'name': 'changed_name'}, 444], 8: [1, {'name': 'changed_name'}, 444]}

#字典的循环
for i in info: #高效
    print(i, info[i])

for k, v in info.items(): #字典转成列表的过程导致低效
    print(k, v)