'abdsafaslhiewhldvjlmvlvk['
 序列化 —— 转向一个字符串数据类型
序列 —— 字符串

 数据存储
 网络上传输的时候

从数据类型 --> 字符串的过程 序列化
 从字符串 --> 数据类型的过程 反序列化

# json *****
# pickle ****
# shelve ***

 json # 数字 字符串 列表 字典 元组
 通用的序列化格式
 只有很少的一部分数据类型能够通过json转化成字符串
pickle
 所有的python中的数据类型都可以转化成字符串形式
pickle序列化的内容只有python能理解
且部分反序列化依赖python代码
shelve
序列化句柄
使用句柄直接操作，非常方便

json

 json dumps序列化方法 loads反序列化方法
 dic = {1:"a",2:'b'}
 print(type(dic),dic)
 import json
 str_d = json.dumps(dic) # 序列化
 print(type(str_d),str_d)
 '{"kkk":"v"}'
 dic_d = json.loads(str_d) # 反序列化
 print(type(dic_d),dic_d)

 

l = [{'k1':'111'},{'k2':'222'},{'k3':'333'}]
f = open('file','w')
import json
for dic in l:
    str_dic = json.dumps(dic)
    f.write(str_dic+'\n')
f.close()

f = open('file')
ll = []
for i in f :
    json.loads(i.strip())
    ll.append(dic)
f.close()
print(ll)

 

dump load

import json
dic = {1:"a",2:'b'}
f = open('fff','w',encoding='utf-8')
json.dump(dic,f)
f.close()
f = open('fff')
res = json.load(f)
f.close()
print(type(res),res)

 

 

pickle

dic = {'k1':'v1','k2':'v2','k3':'v3'}
str_dic = pickle.dumps(dic)
print(str_dic) #一串二进制内容

dic2 = pickle.loads(str_dic)
print(dic2) #字典

import time
struct_time1 = time.localtime(1000000000)
struct_time2 = time.localtime(2000000000)
f = open('pickle_file','wb') #domp，wb
pickle.dump(struct_time1,f)
pickle.dump(struct_time2,f)
f.close()
f = open('pickle_file','rb')  #load，要用rb
struct_time1 = pickle.load(f)
struct_time2 = pickle.load(f)
print(struct_time1.tm_year)
print(struct_time2.tm_year)
f.close()
# 2001
# 2033

View Code

 

shelve

import shelve
f = shelve.open('shelve_file')
f['key'] = {'int':10, 'float':9.5, 'string':'Sample data'} #直接对文件句柄操作，就可以存入数据
f.close()

import shelve
f1 = shelve.open('shelve_file')
existing = f1['key'] #取出数据的时候也只需要直接用key获取即可，但是如果key不存在会报错
f1.close()
print(existing)

import shelve
f = shelve.open('shelve_file', flag='r')
existing = f['key']
print(existing)

f.close()

 

f = shelve.open('shelve_file', flag='r')
existing2 = f['key']
f.close()
print(existing2)

import shelve
f1 = shelve.open('shelve_file')
print(f1['key'])
f1['key']['new_value'] = 'this was not here before'
f1.close()

f2 = shelve.open('shelve_file', writeback=True)
print(f2['key'])
f2['key']['new_value'] = 'this was not here before'
f2.close()