使用不同的标准来过滤一组对象，通过逻辑运算的方式把他们解耦

Demo

  1. """
  2. 过滤器模式
  3. """
  6. class Person:
  7.     def __init__(self, name, gender, marital_status):
  8.         self.name = name
  9.         self.gender = gender
  10.         self.marital_status = marital_status
  12.     def __str__(self):
  13.         return '我是str'
  15.     def __repr__(self):
  16.         return f"name:{self.name}, gender: {self.gender},martial_status:{self.marital_status}"
  19. class Criteria:
  20.     def meet_criteria(self, persons: [Person]):
  21.         raise NotImplementedError
  24. class CriteriaMale(Criteria):
  25.     def meet_criteria(self, persons: [Person]):
  26.         return set(filter(lambda person: person.gender == 'Male', persons))
  29. class CriteriaFemale(Criteria):
  30.     def meet_criteria(self, persons: [Person]):
  31.         return set(filter(lambda person: person.gender == 'Female', persons))
  34. class CriteriaSingle(Criteria):
  35.     def meet_criteria(self, persons: [Person]):
  36.         return set(filter(lambda person: person.marital_status == 'Single', persons))
  39. class AndCriteria(Criteria):
  40.     def __init__(self, criteria: Criteria, other_criteria: Criteria):
  41.         self.criteria = criteria
  42.         self.other_criteria = other_criteria
  44.     def meet_criteria(self, persons: [Person]):
  45.         return set(self.criteria.meet_criteria(persons)) & set(self.other_criteria.meet_criteria(persons))
  48. class OrCriteria(Criteria):
  49.     def __init__(self, criteria: Criteria, other_criteria: Criteria):
  50.         self.criteria = criteria
  51.         self.other_criteria = other_criteria
  53.     def meet_criteria(self, persons: [Person]):
  54.         return set(self.criteria.meet_criteria(persons)) | set(self.other_criteria.meet_criteria(persons))
  57. if __name__ == '__main__':
  58.     persons = [
  59.         Person("Robert", "Male", "Single"),
  60.         Person("John", "Male", "Married"),
  61.         Person("Laura", "Female", "Married"),
  62.         Person("Diana", "Female", "Single"),
  63.         Person("Mike", "Male", "Single"),
  64.         Person("Bobby", "Male", "Single"),
  65.     ]
  67.     male = CriteriaMale()
  68.     female = CriteriaFemale()
  69.     single = CriteriaSingle()
  70.     single_male = AndCriteria(male, single)
  71.     single_or_female = OrCriteria(single, female)
  73.     print(f"males:")
  74.     print(male.meet_criteria(persons))
  76.     print(f"female:")
  77.     print(female.meet_criteria(persons))
  79.     print(f"single:")
  80.     print(single.meet_criteria(persons))
  82.     print("single males:")
  83.     print(single_male.meet_criteria(persons))
  85.     print("single or females:")
  86.     print(single_or_female.meet_criteria(persons))