json&pickle模块shelve模块

Posted 2020-10-13 litzhiai

• json

在不同的编程语言之间传递对象

 1 dic = {‘name‘: ‘alvin‘, ‘age‘: 23, ‘sex‘: ‘male‘}
 2 print(type(dic))  # <class ‘dict‘>
 3 
 4 j = json.dumps(dic)
 5 print(type(j))  # <class ‘str‘>
 6 
 7 f = open(‘序列化对象‘, ‘w‘)
 8 f.write(j)  # -------------------等价于json.dump(dic,f)
 9 f.close()
10 # -----------------------------反序列化<br>
11 import json
12 
13 f = open(‘序列化对象‘)
14 data = json.loads(f.read())  # 等价于data=json.load(f)
15 
16 import json
17 #dct="{‘1‘:111}"#json 不认单引号
18 #dct=str({"1":111})#报错,因为生成的数据还是单引号:{‘one‘: 1}
19 
20 dct=‘{"1":"111"}‘
21 print(json.loads(dct))
22 
23 #conclusion:
24 #        无论数据是怎样创建的，只要满足json格式，就可以json.loads出来,不一定非要dumps的数据才能loads

 

• pickle

pickle是python自己的序列化，想序列化什么就序列化什么，不像json有限制。

import pickle

dic = {‘name‘: ‘alvin‘, ‘age‘: 23, ‘sex‘: ‘male‘}

print(type(dic))  # <class ‘dict‘>

j = pickle.dumps(dic)
print(type(j))  # <class ‘bytes‘>

f = open(‘序列化对象_pickle‘, ‘wb‘)  # 注意是w是写入str,wb是写入bytes,j是‘bytes‘
f.write(j)  # -------------------等价于pickle.dump(dic,f)

f.close()
# -------------------------反序列化
import pickle

f = open(‘序列化对象_pickle‘, ‘rb‘)

data = pickle.loads(f.read())  # 等价于data=pickle.load(f)

print(data[‘age‘])   

 

• shelve模块

shelve模块比pickle模块简单，只有一个open函数，返回类似字典的对象，可读可写;key必须为字符串，而值可以是python所支持的数据类型

import shelve

f=shelve.open(r‘sheve.txt‘)
# f[‘stu1_info‘]={‘name‘:‘egon‘,‘age‘:18,‘hobby‘:[‘piao‘,‘smoking‘,‘drinking‘]}
# f[‘stu2_info‘]={‘name‘:‘gangdan‘,‘age‘:53}
# f[‘school_info‘]={‘website‘:‘http://www.pypy.org‘,‘city‘:‘beijing‘}

print(f[‘stu1_info‘][‘hobby‘])
f.close()