Python自定义类实现字典dict功能的方法

import collections


class Mydict(collections.UserDict):


  def __missing__(self, key):
    if isinstance(key, str):
      raise KeyError(key)
    return self[str(key)]

  def __contains__(self, key):
    return str(key) in self.data

  def __setitem__(self, key, item):
    self.data[str(key)] = item

  def __getattr__(self, key):
    return self.data[str(key)]


if __name__ == '__main__':
  mydict = Mydict((('a',1),('c',('d',3)),('b',2)))

  print(mydict)
  print(mydict.a)
  print(mydict['a'])