Python序列化json模块

json 序列化/反序列化模块

import json
import ujson
"""
json格式的数据,所有的编程语言都能识别,本身是字符串
类型有要求: int float bool str list tuple dict None

json   主要应用于传输数据 , 序列化成字符串
pickle 主要应用于存储数据 , 序列化成二进制字节流
ujson  与json一样使用，但效率更高
"""

json 基本用法

json => dumps 和 loads

"""ensure_ascii=False 显示中文 sort_keys=True 按键排序"""
dic = {"name":"梁新宇","sex":"野味","age":22,"family":["爸爸","妈妈","姐姐"]}
res = json.dumps(dic,ensure_ascii=False,sort_keys=True)
print(res , type(res))

dic = json.loads(res)
print(dic , type(dic))

json => dump 和 load

with open("lianxi3.json",mode="w",encoding="utf-8") as fp:
	json.dump(dic,fp,ensure_ascii=False)
with open("lianxi3.json",mode="r",encoding="utf-8") as fp:
	dic = json.load(fp)
print(dic , type(dic))

---

json 和 pickle 之间的区别

# 1.json
# json 连续dump数据 , 但是不能连续load数据  , 是一次性获取所有内容进行反序列化.
dic1 = {"a":1,"b":2}
dic2 = {"c":3,"d":4}
with open("lianxi4.json",mode="w",encoding="utf-8") as fp:
	json.dump(dic1,fp)
	fp.write("\n")
	json.dump(dic2,fp)
	fp.write("\n")

# 不能连续load,是一次性获取所有数据 , error
"""
with open("lianxi4.json",mode="r",encoding="utf-8") as fp:
	dic = json.load(fp)
"""

# 解决办法 loads(分开读取)
with open("lianxi4.json",mode="r",encoding="utf-8") as fp:
	for line in fp:
		dic = json.loads(line)
		print(dic,type(dic))


# 2.pickle
import pickle
# pickle => dump 和 load
# pickle 连续dump数据,也可以连续load数据
with open("lianxi5.pkl",mode="wb") as fp:
	pickle.dump(dic1,fp)
	pickle.dump(dic2,fp)
	pickle.dump(dic1,fp)
	pickle.dump(dic2,fp)


# 方法一
"""
with open("lianxi5.pkl",mode="rb") as fp:
	dic1 = pickle.load(fp)
	dic2 = pickle.load(fp)
	print(dic1)
	print(dic2)
"""
# 方法二 (扩展)
"""try .. except .. 把又可能报错的代码放到try代码块中,如果出现异常执行except分支,来抑制报错"""
# 一次性拿出所有load出来的文件数据
try:
	with open("lianxi5.pkl",mode="rb") as fp:

		while True:
			dic = pickle.load(fp)
			print(dic)
except:
	pass

"""

# json 和 pickle 两个模块的区别:
(1)json序列化之后的数据类型是str,所有编程语言都识别,
   但是仅限于(int float bool)(str list tuple dict None)
   json不能连续load,只能一次性拿出所有数据
(2)pickle序列化之后的数据类型是bytes,用于数据存储
   所有数据类型都可转化,但仅限于python之间的存储传输.
   pickle可以连续load,多套数据放到同一个文件中

"""