如何创建可根据成员类属性自动新增聚合方法的Python集合类

方案1：用__getattr__动态生成聚合属性（零维护成本，最省心） #

这个方案不需要手动新增任何Team类的代码，只要Player新增property，Team会自动支持对应4种聚合属性：

from statistics import mean, median
from functools import lru_cache

class Player:
    def __init__(self, name, age, score=None):
        self.name = name
        self._age = age
        self._score = score

    @property
    def age(self):
        return self._age

    # 新增property完全不用改Team代码
    @property
    def score(self):
        return self._score

    # 提前收集所有公开的property名称，用于合法性校验
    @classmethod
    def get_properties(cls):
        return [k for k, v in vars(cls).items() if isinstance(v, property)]

class Team:
    def __init__(self, players):
        self.players = players
        self._player_properties = set(Player.get_properties())
        # 定义聚合规则：前缀 -> 计算函数
        self._agg_rules = {
            'all_': lambda values: {p.name: v for p, v in zip(self.players, values)},
            'total_': sum,
            'average_': mean,
            'median_': median
        }

    def __getattr__(self, attr_name):
        # 匹配前缀和属性名
        for prefix, agg_func in self._agg_rules.items():
            if attr_name.startswith(prefix):
                prop_name = attr_name[len(prefix):]
                # 处理单复数匹配，比如all_ages对应age，all_scores对应score
                if prop_name.endswith('s'):
                    prop_name = prop_name[:-1]
                if prop_name in self._player_properties:
                    # 提取所有玩家对应的属性值
                    values = [getattr(p, prop_name) for p in self.players]
                    return agg_func(values)
        # 没有匹配的属性走默认报错逻辑
        raise AttributeError(f"'Team' object has no attribute '{attr_name}'")

# 测试代码
p1 = Player('John', 8, 90)        
p2 = Player('Tim', 9, 85)        
p3 = Player('Annie', 11, 95)        
team = Team([p1, p2, p3])

# 原有age属性正常使用
print(team.all_ages) # {'John':8, 'Tim':9, 'Annie':11}
print(team.total_age) # 28
# 新增的score属性自动支持
print(team.all_scores) # {'John':90, 'Tim':85, 'Annie':95}
print(team.average_score) # 90

这个方案的优势是完全适配Player属性的新增/修改/删除，不需要对Team类做任何调整，适合属性频繁迭代的业务场景。如果担心重复计算性能问题，可以给__getattr__加缓存，或者在第一次计算后把属性动态绑定到实例上。

方案2：预生成property（支持IDE自动补全，对开发者更友好） #

如果需要IDE能识别所有聚合属性，可以用类装饰器在定义Team类的时候自动批量生成所有property：

def generate_agg_properties(player_cls):
    agg_rules = {
        'all_': lambda self, prop: {p.name: getattr(p, prop) for p in self.players},
        'total_': lambda self, prop: sum(getattr(p, prop) for p in self.players),
        'average_': lambda self, prop: mean(getattr(p, prop) for p in self.players),
        'median_': lambda self, prop: median(getattr(p, prop) for p in self.players),
    }
    def decorator(team_cls):
        # 获取所有Player的property
        player_props = [k for k, v in vars(player_cls).items() if isinstance(v, property)]
        for prop in player_props:
            for prefix, func in agg_rules.items():
                # 生成属性名，all_前缀加复数s
                attr_name = f"{prefix}{prop}s" if prefix == 'all_' else f"{prefix}{prop}"
                # 绑定property
                setattr(team_cls, attr_name, property(lambda self, p=prop, f=func: f(self, p)))
        return team_cls
    return decorator

# 使用装饰器修饰Team类
@generate_agg_properties(Player)
class Team:
    def __init__(self, players):
        self.players = players

后续只要Player新增了property，重新加载代码后Team就会自动生成对应的聚合属性，IDE可以正常提示补全。

内容的提问来源于stack exchange，提问作者j_becker