重新梳理Python基础（10）

1. 今天学了一些概念。（书的第41~43章）

用这个方法可以分清楚class、object、instance

## Animal is-a object (yes, sort of confusing) look at the extra credit

class Animal(object):

    pass



## Dog is-a animal, it has-a name

class Dog(Animal):



    def __init__(self, name):

        ## ??

        self.name = name



## Cat is-a animal, it has-a name

class Cat(Animal):



    def __init__(self, name):

        ## ??

        self.name = name



## Person is-a object, it has-a name and pet

class Person(object):



    def __init__(self, name):

        ## ??

        self.name = name



        ## Person has-a pet of some kind

        self.pet = None



## Employee is-a Person, it has-a name and salary

class Employee(Person):



    def __init__(self, name, salary):

        ## ?? hmm what is this strange magic?

        super(Employee, self).__init__(name)

        ## ??

        self.salary = salary



## Fish is-a object

class Fish(object):

    pass



## Salmon is-a Fish

class Salmon(Fish):

    pass



## Halibut is-a Fish

class Halibut(Fish):

    pass





## rover is-a Dog

rover = Dog("Rover")



## satan is-a Cat

satan = Cat("Satan")



## mary is-a Person

mary = Person("Mary")



## mary has-a pet, satan

mary.pet = satan



## frank is-a employee, it has-a salary 120000

frank = Employee("Frank", 120000)



## frank has-a pet, rover

frank.pet = rover



## flipper is-a fish

flipper = Fish()



## crouse is-a salmon

crouse = Salmon()



## harry is-a halibut

harry = Halibut()

用这种方式可以比较清楚的明白对象、类和实例的概念。

2. OOP

1. Write or draw about the problem.
2. Extract key concepts from #1 and research them.
3. Create a class hierarchy and object map for the concepts.
4. Code the classes and a test to run them.
5. Repeat and refine.