序列化

Posted 2020-10-20 always on the way

（1）python提供了pickle模块实现序列化
    import pickle
    d=dict(name=‘Bob‘,age=30,score=98)
    pickle.dumps(d) # 把任意对象序列化为一个bytes

    f=open(‘dump.txt‘,‘wb‘)  # 以二进制写模式打开
    pickle.dump(d,f)
    f.close()

    f=open(‘dump.txt‘,‘rb‘)
    pickle.load(f)
    f.close()

（2）JSON
JSON类型 Python类型
{}         dict
[]         list
"string"   str
1234.56    int或float
true/false True/False
null       None

    import json
    d=dict(name=‘Bob‘,age=30,score=88)
    json.dumps(d)

    json_str=‘{"age":20,"score":88,"name":"bob"}‘
    json.loads(json_str)

    import json
    class Student(object):
        def __init__(self,name,age,score):
            self.name=name
            self.age=age
            self.score=score
    def student2dict(std):
        return {
            ‘name‘:std.name,
            ‘age‘:std.age,
            ‘acore‘:std.score
        }
    s=Student(‘bob‘,20,99)
    print(json.dumps(s,default=student2dict))
    print(json.dumps(s,default=lambda obj:obj.__dict__)) # class的实例都有一个__dict__属性，他就是一个dict

    def dict2student(d):
        return Student(d[‘name‘],d[‘age‘],d[‘score‘])
    json_str=‘{"age":20,"score":88,"name":"bob"}‘
    print(json.loads(json_str,object_hook=dict2student))