序列化：把内存中的数据类型转换为字符串，以便能够存储到硬盘或通过网络传输到远程，因为硬盘或网络传输时只能接受bytes。
反序列化：把硬盘中的数据转换为内存数据类型

#!/usr/bin/env python# -*- coding:utf-8 -*-# Author: vitadata = {"haha":"哈哈"}fw = open(file="写文件.txt",mode="w",encoding="utf-8")fw.write(str(data)) # 序列化fw.close()fr = open(file="写文件.txt",mode="r",encoding="utf-8")d = fr.read()d = eval(d) # 反序列化print(d)fr.close()E:\PythonProject\python-test\venvP3\Scripts\python.exe E:/PythonProject/python-test/BasicGrammer/test.py{'haha': '哈哈'}Process finished with exit code 02.json

优点：跨语言、体积小
缺点：只能支持int\str\list\tuple\dict

#!/usr/bin/env python# -*- coding:utf-8 -*-# Author: vitaimport jsondata = {"haha":"哈哈"}# dumps并没有把内容写入到硬盘中d = json.dumps(data)print(d,type(d))E:\PythonProject\python-test\venvP3\Scripts\python.exe E:/PythonProject/python-test/BasicGrammer/test.py{"haha": "\u54c8\u54c8"} <class 'str'>Process finished with exit code 0json.loads()反序列化为其实际数据类型,就不需要使用eval()把内存中数据转换为相应的数据类型了

#!/usr/bin/env python# -*- coding:utf-8 -*-# Author: vitaimport jsondata = {"haha":"哈哈"}# dumps并没有把内容写入到硬盘中d = json.dumps(data)d2 = json.loads(d)print(d2,type(d2))E:\PythonProject\python-test\venvP3\Scripts\python.exe E:/PythonProject/python-test/BasicGrammer/test.py{'haha': '哈哈'} <class 'dict'>Process finished with exit code 0json.dump()序列化，并保存到文件中

#!/usr/bin/env python# -*- coding:utf-8 -*-# Author: vitaimport jsondata = {"haha":"哈哈"}fw = open(file="写文件.txt",mode="w",encoding="utf-8")d = json.dump(data,fw)E:\PythonProject\python-test\venvP3\Scripts\python.exe E:/PythonProject/python-test/BasicGrammer/test.pyProcess finished with exit code 0查看文件中的内容{"haha": "\u54c8\u54c8"}json.load()反序列化，从文件中读取内容，转为实际的数据类型

#!/usr/bin/env python# -*- coding:utf-8 -*-# Author: vitaimport jsondata = {"haha":"哈哈"}fr = open(file="写文件.txt",mode="r",encoding="utf-8")d = json.load(fr)print(d,type(d))E:\PythonProject\python-test\venvP3\Scripts\python.exe E:/PythonProject/python-test/BasicGrammer/test.py{'haha': '哈哈'} <class 'dict'>Process finished with exit code 0尝试多次dump

#!/usr/bin/env python# -*- coding:utf-8 -*-# Author: vitaimport jsondata = {"haha":"哈哈"}data2 = {"hehe":"呵呵"}fw = open(file="写文件.json",mode="w",encoding="utf-8")json.dump(data,fw)json.dump(data2,fw)E:\PythonProject\python-test\venvP3\Scripts\python.exe E:/PythonProject/python-test/BasicGrammer/test.pyProcess finished with exit code 0查看文件内容{"haha": "\u54c8\u54c8"}{"hehe": "\u5475\u5475"}多次dump是没有报错，但是load()多次dump()后load()

#!/usr/bin/env python# -*- coding:utf-8 -*-# Author: vitaimport jsondata = {"haha":"哈哈"}data2 = {"hehe":"呵呵"}fr = open(file="写文件.json",mode="r",encoding="utf-8")print(json.load(fr))E:\PythonProject\python-test\venvP3\Scripts\python.exe E:/PythonProject/python-test/BasicGrammer/test.pyTraceback (most recent call last): File "E:/PythonProject/python-test/BasicGrammer/test.py", line 8, in <module> print(json.load(fr)) File "D:\software2\Python3\install\lib\json\__init__.py", line 299, in load parse_constant=parse_constant, object_pairs_hook=object_pairs_hook, **kw) File "D:\software2\Python3\install\lib\json\__init__.py", line 354, in loads return _default_decoder.decode(s) File "D:\software2\Python3\install\lib\json\decoder.py", line 342, in decode raise JSONDecodeError("Extra data", s, end)json.decoder.JSONDecodeError: Extra data: line 1 column 25 (char 24)Process finished with exit code 1"说明不要dump多次，虽然dump不报错，但是load不回来了。因为在一行有两种类型的数据"3.pickle

优点：转为python设计，支持python所有数据类型。
缺点：只能在python中使用，存储数据占用空间大。

#!/usr/bin/env python# -*- coding:utf-8 -*-# Author: vitaimport pickledata = {"haha":"哈哈"}d = pickle.dumps(data)print(d,type(d))l = pickle.loads(d)print(l,type(l))E:\PythonProject\python-test\venvP3\Scripts\python.exe E:/PythonProject/python-test/BasicGrammer/test.pyb'\x80\x03}q\x00X\x04\x00\x00\x00hahaq\x01X\x06\x00\x00\x00\xe5\x93\x88\xe5\x93\x88q\x02s.' <class 'bytes'>{'haha': '哈哈'} <class 'dict'>Process finished with exit code 0dump()&load()

#!/usr/bin/env python# -*- coding:utf-8 -*-# Author: vitaimport pickledata = {"haha":"哈哈"}fw = open(file="写文件.json",mode="wb") #由于dump后数据类型是bytes类型，所以mode="wb"d = pickle.dump(data,fw)fw.close()fr = open(file="写文件.json",mode="rb") #写入时是wb,读取时是rbl = pickle.load(fr)print(l,type(l))fr.close()E:\PythonProject\python-test\venvP3\Scripts\python.exe E:/PythonProject/python-test/BasicGrammer/test.py{'haha': '哈哈'} <class 'dict'>Process finished with exit code 0函数也可被序列化

#!/usr/bin/env python# -*- coding:utf-8 -*-# Author: vitaimport pickledef fun(): print("232")d = pickle.dumps(fun)print(d,type(d))l = pickle.loads(d)print(l,type(l))E:\PythonProject\python-test\venvP3\Scripts\python.exe E:/PythonProject/python-test/BasicGrammer/test.pyb'\x80\x03c__main__\nfun\nq\x00.' <class 'bytes'><function fun at 0x00000157C0883E18> <class 'function'>Process finished with exit code 0#!/usr/bin/env python# -*- coding:utf-8 -*-# Author: vitaimport pickledef fun(): print("232")fw = open(file="写文件.json",mode="wb")d = pickle.dump(fun,fw)fw.close()fr = open(file="写文件.json",mode="rb")l = pickle.load(fr)print(l,type(l))fr.close()E:\PythonProject\python-test\venvP3\Scripts\python.exe E:/PythonProject/python-test/BasicGrammer/test.py<function fun at 0x0000017668504C80> <class 'function'>Process finished with exit code 04.shelve

可序列化多次，反序列化多次，就像操作字典一样操作数据
shelve是一个简单的k,v将内存数据通过文件持久化的模块，可以持久化任何pickle可支持的python数据格式

"注意：shelve打开文件时，文件如果是存在的，是会报下面的错误的"E:\PythonProject\python-test\venvP3\Scripts\python.exe E:/PythonProject/python-test/BasicGrammer/test.pyTraceback (most recent call last): File "E:/PythonProject/python-test/BasicGrammer/test.py", line 5, in <module> f = shelve.open("写文件.txt") File "D:\software2\Python3\install\lib\shelve.py", line 243, in open return DbfilenameShelf(filename, flag, protocol, writeback) File "D:\software2\Python3\install\lib\shelve.py", line 227, in __init__ Shelf.__init__(self, dbm.open(filename, flag), protocol, writeback) File "D:\software2\Python3\install\lib\dbm\__init__.py", line 88, in open raise error[0]("db type could not be determined")dbm.error: db type could not be determinedProcess finished with exit code 1

"shelve序列化"#!/usr/bin/env python# -*- coding:utf-8 -*-# Author: vitaimport shelvef = shelve.open("写文件.txt") #此处的文件不能是已经存在的names = ["vita","丽丽","lyly"]info = {"name":"vita","age":23}f["names"]=namesf["info_dic"]=infof.close()E:\PythonProject\python-test\venvP3\Scripts\python.exe E:/PythonProject/python-test/BasicGrammer/test.pyProcess finished with exit code 0写入成功后，产生如下的文件

"shelve反序列化"#!/usr/bin/env python# -*- coding:utf-8 -*-# Author: vitaimport shelvef = shelve.open("写文件.txt")print(f["names"])print(f["info_dic"])E:\PythonProject\python-test\venvP3\Scripts\python.exe E:/PythonProject/python-test/BasicGrammer/test.py['vita', '丽丽', 'lyly']{'name': 'vita', 'age': 23}Process finished with exit code 0shelve相关操作

"查询">>> f = shelve.open("写文件.txt")>>> f<shelve.DbfilenameShelf object at 0x000002A52DB5E780>>>> f.keys()KeysView(<shelve.DbfilenameShelf object at 0x000002A52DB5E780>)>>> list(f.keys())['names', 'info_dic']>>> list(f.items())[('names', ['vita', '丽丽', 'lyly']), ('info_dic', {'name': 'vita', 'age': 23})]>>> f.get("names")['vita', '丽丽', 'lyly']>>> f.get("info_dic"){'name': 'vita', 'age': 23}>>> f["names"][1]'丽丽'"修改">>> f["names"][1]="超超" #这样修改是不可以的>>> f["names"][1] "'丽丽'>>> f["names"]=["ccc","lll"] #可以这样修改>>> f["names"]['ccc', 'lll']>>> f.items()ItemsView(<shelve.DbfilenameShelf object at 0x000002A52DB5E780>)>>> list(f.items())[('names', ['ccc', 'lll']), ('info_dic', {'name': 'vita', 'age': 23})]"删除">>> del f["names"]>>> list(f.items())[('info_dic', {'name': 'vita', 'age': 23})]"增加">>> f["scores"]=[90,89]>>> list(f.items())[('info_dic', {'name': 'vita', 'age': 23}), ('scores', [90, 89])]