JSON 復雜對象字典的序列化

Question

我正在嘗試序列化字典playersElo以將其作為/從 JSON 保存/加載。 但由於它不是可序列化的 object ，所以我找不到辦法。

playersElo={} # dictionnary of {<int> : <PlayerElo>}
playersElo[1] = PlayerElo()
playersElo[2] = PlayerElo()
...

class PlayerElo:
    """
    A class to represent a player in the Elo Rating System
    """
    def __init__(self, name: str, id: str, rating):
        self.id = id
        self.name = name
        # comment the 2 lines below in order to start with a rating associated
        # to current player rank
        self.eloratings = {0: 1500}
        self.elomatches = {0: 0}
        self.initialrating = rating

Answer 1

也許這可以成為您的起點。 序列化程序從 object 中獲取__dict__屬性並創建一個新的 dict-of-dicts，然后將其寫入 JSON。 解串器創建一個虛擬 object，然后在進入的過程中更新__dict__ 。

import json

class PlayerElo:
    """
    A class to represent a player in the Elo Rating System
    """
    def __init__(self, name: str, id: str, rating):
        self.id = id
        self.name = name
        self.eloratings = {0: 1500}
        self.elomatches = {0: 0}
        self.initialrating = rating


playersElo={} # dictionnary of {<int> : <PlayerElo>}
playersElo[1] = PlayerElo('Joe','123',999)
playersElo[2] = PlayerElo('Bill','456',1999)

def serialize(ratings):
    newdict = {i:j.__dict__ for i,j in ratings.items()}
    json.dump( newdict, open('x.json','w') )

def deserialize():
    o = json.load(open('x.json'))
    pe = {}
    for k,v in o.items():
        obj = PlayerElo('0','0',0)
        obj.__dict__.update( o )
        pe[int(k)] = obj
    return pe

print(playersElo)
serialize( playersElo )
pe = deserialize( )
print(pe)

Answer 2

您可以擴展json.JSONEncoder來處理 class 的實例。 模塊文檔中有示例，但這里有一個使用PlayerElo class 的原因。

注意：另請參閱我對使用常規編碼器可序列化 object JSON問題的回答，以獲得更通用的方法。

import json


class PlayerElo:
    """ A class to represent a player in the Elo Rating System. """

    def __init__(self, name: str, id: str, rating):
        self.id = id
        self.name = name
        # comment the 2 lines below in order to start with a rating associated
        # to current player rank
        self.eloratings = {0: 1500}
        self.elomatches = {0: 0}
        self.initialrating = rating


class MyJSONEcoder(json.JSONEncoder):
    def default(self, obj):
        if isinstance(obj, PlayerElo):
            return dict(type='PlayerElo', name=obj.name, id = obj.id,
                        rating=obj.initialrating)
        return super().default(obj)


playersElo={} # dictionnary of {<int> : <PlayerElo>}
playersElo[1] = PlayerElo('Bob', 'thx1138', 4)
playersElo[2] = PlayerElo('Sue', 'p-138', 3)

from pprint import pprint
my_encoder = MyJSONEcoder()
pprint(my_encoder.encode(playersElo))

這里是它生成並打印的 JSON 字符串：

('{"1": {"type": "PlayerElo", "name": "Bob", "id": "thx1138", "rating": 4}, '
 '"2": {"type": "PlayerElo", "name": "Sue", "id": "p-138", "rating": 3}}')