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
  
  

• python编程范式

  两种思路：
  1> 面向对象
  把大问题逐步拆分为小问题，从上到下；
  2> 面向过程