蛇院自习室

defaultdict 学习pytorch的时候接触到了这个包，总结一下自己的理解

from collections import defaultdict

class Person():
    def __init__(self):
        self.name = 'Tom'
        self.age = 20
        self.wallet = defaultdict(Wallet)
        self.property = defaultdict(Property)

    def add_wallet(self, key, val):
        self.wallet[key] = val

    def add_property(self, key, val):
        self.property[key] = val

    def __getattr__(self, attr):
        if attr in self.wallet:
            return self.wallet[attr]
        elif attr in self.property:
            return self.property[attr]
        elif attr in self.__dict__:
            return self.__dict__[attr]
        else:
            raise AttributeError('该item不存在，查询出错！')

  class Wallet():
    def __init__(self):
        pass

  class Property():
      def __init__(self):
          pass

  p = Person()
  print(p.name)   # Tom
  p.add_wallet('RMB', 1000)
  print(p.RMB)    # 1000
  p.add_property('house', 2)
  print(p.house)  # 2