python笔记(序列化模块)

序列化模块
序列化 - 转向一个字符串数据类型

1.json
dumps,loads:转化数据类型
dump,load：向文件写和读

import json
dic = {'1':'中国','2':'usa'}
with open('json','w',encoding='utf-8') as f:
    json.dump(dic,f,ensure_ascii=False)      #ensure_ascii:可以决定你写进文件中的内容展现方式
with open('json',encoding='utf-8') as f:
    print(json.load(f))

{‘1’: ‘中国’, ‘2’: ‘usa’}#打印出的
{“1”: “中国”, “2”: “usa”}#文件中的

2.pickle
pickle :文件操作必须加b，只能用于python

import pickle
import time

struct_time1 = time.localtime(100000)
struct_time2 = time.localtime(100000)
f = open('pickle','wb')
pickle.dump(struct_time1,f)
pickle.dump(struct_time2,f)
f.close()
f = open('pickle','rb')
struct_time1 = pickle.load(f)
struct_time2 = pickle.load(f)
print(struct_time1.tm_year)
print(struct_time2.tm_year)
f.close()

3.shelve

import shelve
f = shelve.open('shelve')
f['key'] = {'int':2,'float':1.1,'str':'yuyu'}  #直接对文件句柄操作，就可以存入数据
f.close()

import shelve
f1 = shelve.open('shelve')
existing = f1['key']#取出时可以直接对‘key’操作，但'key'不存在会报错
f1.close()
print(existing)