模块2

本节主要内容
1. 什么是序列化

2. pickle(重点)

3. shelve

4. json(重点)

5. configparser模块

⼀一. 什么是序列列化       

在我们存储数据或者⽹网络传输数据的时候. 需要对我们的对象进⾏行行处理理. 把对象处理理成 ⽅方便便存储和传输的数据格式. 这个过程叫序列列化. 不同的序列列化, 结果也不同. 但是⽬目的是⼀一 样的. 都是为了了存储和传输.        

在python中存在三种序列化的方案.           

1. pickle. 可以将我们python中的任意数据类型转化成bytes并写入到⽂文件中.  同样也 可以把⽂文件中写好的bytes转换回我们python的数据. 这个过程被称为反序列列化           

2. shelve. 简单另类的⼀一种序列化的方案. 有点儿类似后面我们学到的redis. 可以作为 ⼀种小型的数据库来使⽤用           

3. json. 将python中常见的字典, 列列表转化成字符串. 是目前前后端数据交互使用频率 最高的一种数据格式.

import pickle

# class Cat:
#     def __init__(self, name, color):
#         self.name = name
#         self.color = color
#
#     def chi(self):
#         print("%s猫会吃老鼠" % self.name)

# c = Cat("汪峰","黑色")
#
# bs = pickle.dumps(c) # 把一个对象转化成bytes
# print(bs)

用户登陆

class User:
    def __init__(self, username, password):
        self.username = username
        self.password = password

class client:
    def regist(self):
        uname = input("please input your username:")
        pwd = input("please input your password:")
        user = User(uname, pwd)
        pickle.dump(user, open("userinfo", mode="ab"))
        print("regist successful!!!")

    def login(self):
        uname = input("please input your username:")
        pwd = input("please input your password:")
        f = open("userinfo", mode="rb")
        while 1:
            try:
                u = pickle.load(f) # 从文件里把对象拿出来
                if u.username == uname and u.password == pwd:
                    print("login successful !!")
                    break

            except Exception as e:
                print("login failed !!!")
                break

c = client()
# c.regist()
# c.regist()
# c.regist()
# c.regist()
c.login()

 三. shelve       

shelve提供python的持久化操作. 什叫持久化操作呢? 说⽩白话,就是把数据写到硬盘上. 在操作shelve的时候非常的像操作⼀一个字典.  这个东⻄西到后期. 就像redis差不多.

import shelve

# d = shelve.open("sylar") # 文件类型的字典
# d['wf'] = "汪峰"
# d.close()
#
# d = shelve.open("sylar")
# print(d['wf'])
# d.close()

# d = shelve.open("sylar") # 文件类型的字典
# d['wf'] = {"name":"汪峰", "age": 18, "wife":{"name":"章子怡", "hobby":"拍电影"}}
# d.close()

# d = shelve.open("sylar", writeback=True) # 文件类型的字典 wirteback把修改的内容自动的回写到文件中
# d['wf']['wife']['hobby'] = "当导师" #　改
# d.close()

# d = shelve.open("sylar") # 文件类型的字典
# print(d['wf'])
# d.close()


d = shelve.open("sylar")
for k, v in d.items():
    print(k, v)
print(type(d))

五. configparser模块

 

import configparser

# config = configparser.ConfigParser() # 创建对象
#
# config['DEFAULT'] = {  # 特殊
#     "name":"腾讯qq木马",
#     "time":"qq更新时间",
#     "version":"1.0"
# }
# config['SERVER_1'] = {
#     "IP":"192.168.1.123",
#     "port":"12306"
# }
# config['SERVER_2'] = {
#     "IP":"192.168.1.178",
#     "port":"12311"
# }
# config['SERVER_3'] = {
#     "IP":"192.168.1.176",
#     "port":"12312"
# }
#
# # 写入到文件
# config.write(open("qq.ini", mode="w", encoding="utf-8"))


# 读取内容
config = configparser.ConfigParser()
# 读取内容
config.read("qq.ini", encoding="utf-8") # 此时我们把文件中的内容读取到config
print(config['SERVER_1']['IP']) # 字典
print(config['SERVER_2']['name'])
print(config.get("SERVER_3", "IP")) # 字典

for k, v in config['DEFAULT'].items():
    print(k, v)

# config = configparser.ConfigParser()
# # 读取内容
# config.read("qq.ini", encoding="utf-8") # 此时我们把文件中的内容读取到config
# config['SERVER_1']['NAME'] = "哈哈哈"
# config.write(open("qq.ini", mode="w", encoding="utf-8"))

四. json(重点)

终于到json了了. json是我们前后端交互的枢纽. 相当于编程界的普通话. ⼤大家沟通都⽤用 json. 为什什么这样呢? 因为json的语法格式可以完美的表⽰示出⼀一个对象. 那什什么是json: json全 称javascript object notation. 翻译过来叫js对象简谱.  很复杂是吧? 来上⼀一段我们认识的代 码:

import  json

# # 准备一个字典
# dic = {"a": "小萝莉", "b": "大萝莉", "c": "猥琐大叔", "d": False, "e": None}
# #　python中可以直接把字典或者列表转化成json
# s = json.dumps(dic, ensure_ascii=False)  # pickle
# print(type(s))
# print(s)

# s = '{"a": "小萝莉", "b": "大萝莉", "c": "猥琐大叔", "d": false, "e": null}'
# d = json.loads(s) # 把json转化成字典
# print(d)
# print(type(d))



# dic = {"a": "小萝莉", "b": "大萝莉", "c": "猥琐大叔", "d": False, "e": None, "wf":{"name":"半壁江山", "hobby":"皮裤"}}
# f = open("sylar.json", mode="w", encoding="utf-8")
# json.dump(dic, f, ensure_ascii=False, indent=4) # 4个空格 = 1个tab
#
# f = open("sylar.json", mode="r", encoding="utf-8")
# d = json.load(f)
# print(d)

# class Person:
#     def __init__(self, firstName, lastName):
#         self.firstName = firstName
#         self.lastName = lastName
#
# s = '{"firstName": "尼古拉斯", "lastName": "刘能"}'
# def func(dic):
#     return Person(dic['firstName'], dic["lastName"])
#
# p = json.loads(s, object_hook=func) # 通过函数func把字典转换回对象
# print(p.firstName, p.lastName)


# p = Person("尼古拉斯", "刘能")
# 把对象转换成json
# s = json.dumps(p.__dict__, ensure_ascii=False) # 方案一, 转的是字典
# def func(obj):
#     return {
#         "firstName": obj.firstName,
#         "lastName": obj.lastName
#     }
# s = json.dumps(p, default=func, ensure_ascii=False) # 方案二 转化的也是字典
# print(s)

dic1 = {"name":'毒液', "评分": "0.9"}
dic2 = {"name":'与神同行', "评分": "10"}
dic3 = {"name":'看不见的客人', "评分": "9.5"}

# lst = [dic1, dic2, dic3]
# f = open("movie.json", mode="w", encoding="utf-8")
# for d in lst:
#     s = json.dumps(d, ensure_ascii=False)
#     f.write(s+"
")

# f = open("movie.json", mode="r", encoding="utf-8")
# dic1 = json.load(f) # 当json文件中保存多个json的时候不能一次性全部都读取出来
# print(dic1)

f = open("movie.json", mode="r", encoding="utf-8")
for line in f:
    line = line.strip()
    if line == "":
        continue
    else:
        d = json.loads(line) # 一行一行的处理
        print(d)