python day28--json,pickle,hashlib,logging

一、json格式的限制

1.json格式的key必须是字符串数据类型,如果是数字dumps后会被转为字符串。

# dic = {1:2,3:4}
# str_dic = json.dumps(dic)
# print(str_dic)
# new_dic = json.loads(str_dic)
# print(new_dic)

2.元组可以作为vaule但会被转为列表,并且不能作为key

3.可以多次将数据dump进文件,但不能load出来。

# dic = {'abc':(1,2,3)}
# lst = ['aaa',123,'bbb',12.456]
# with open('json_demo','w') as f:
#     json.dump(lst,f)
#     json.dump(dic,f)
# with open('json_demo') as f:
#     ret = json.load(f)
#     print(ret)
#报错

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转载自www.cnblogs.com/snackpython/p/10147381.html
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