Python--面向对象的程序设计之组合应用、开发软件规范

组合应用:

class Teacher:
    def __init__(self,name,age,sex,salary,level):
        self.name=name
        self.age=age
        self.sex=sex
        self.salary=salary
        self.level=level

    def walk(self):
        print('%s is walking'%self.name)

    def teach(self):
        print('%s is teaching'%self.name)

    def tell_info(self):
        print('''
        ----------%s info--------
        NAME:%s
        AGE:%s
        SEX:%s
        SAL:%s
        LEVEL:%s
        '''%(self.name,self.name,self.age,self.sex,self.salary,self.level))
class Date:
    def __init__(self,year,mon,day):
        self.year=year
        self.mon=mon
        self.day=day

    def tell_birth(self):
        print('%s-%s-%s'%(self.year,self.mon,self.day))

alex=Teacher('alex',84,'male',30000,-1)
Birth=Date(1900,13,43)
alex.birth=Birth

alex.tell_info()
print(alex.birth)  #<__main__.Date object at 0x00000000027B2860>
alex.birth.tell_birth() 
运行结果：

        ----------alex info--------
        NAME:alex
        AGE:84
        SEX:male
        SAL:30000
        LEVEL:-1
        
<__main__.Date object at 0x00000000027B2860>
1900-13-43

改动Date类，表明是谁的生日：

class Date:
    def __init__(self,name,year,mon,day):
        self.name=name
        self.year=year
        self.mon=mon
        self.day=day

    def tell_birth(self):
        print('%s:%s-%s-%s'%(self.name,self.year,self.mon,self.day))

alex=Teacher('alex',84,'male',30000,-1)
Birth=Date(alex.name,1900,13,43)
alex.birth=Birth

alex.birth.tell_birth()
运行结果：
alex:1900-13-43

组合的应用：

class Teacher:
    def __init__(self,name,age,sex,salary,level):
        self.name=name
        self.age=age
        self.sex=sex
        self.salary=salary
        self.level=level

    def walk(self):
        print('%s is walking'%self.name)

    def teach(self):
        print('%s is teaching'%self.name)

    def tell_info(self):
        print('''
        ----------%s info--------
        NAME:%s
        AGE:%s
        SEX:%s
        SAL:%s
        LEVEL:%s
        '''%(self.name,self.name,self.age,self.sex,self.salary,self.level))


class Student:
    def __init__(self,name,age,sex,group):
        self.name=name
        self.age=age
        self.sex=sex
        self.group=group

    def walk(self):
        print('%s is walking'%self.name)

    def study(self):
        print('%s is studying'%self.name)

    def tell_info(self):
        print("""
        -------%s info-------
        NAME:%s
        AGE:%s
        SEX:%s
        GROUP:%s
        """%(self.name,self.name,self.age,self.sex,self.group))

class Course:
    def __init__(self,name,price,period):
        self.name=name
        self.price=price
        self.period=period

    def tell_course(self):
        print('''
        ------%s info------
        course name:%s
        course price:%s
        course period:%s
        '''%(self.name,self.name,self.price,self.period))

alex=Teacher('alex',84,'male',30000,-1)
xiaohuang=Student('xiaohuang',73,'male','group8')
python=Course('Python',15800,'6 mons')
linux=Course('Linux',12800,'3 mons')
go=Course('Go',9800,'4 mons')

alex.courses=[]
alex.courses.append(python)
alex.courses.append(go)
print(alex.courses)  #[<__main__.Course object at 0x0000000001EAA128>, <__main__.Course object at 0x0000000001E98CC0>]


xiaohuang.courses=[]
xiaohuang.courses.append(python)
print(xiaohuang.courses)  #[<__main__.Course object at 0x0000000001EAA128>]
运行结果：
[<__main__.Course object at 0x0000000001EAA128>, <__main__.Course object at 0x0000000001E98CC0>]
[<__main__.Course object at 0x0000000001EAA128>]

进一步优化，可以查看对象的课程：

class Teacher:
    def __init__(self,name,age,sex,salary,level):
        self.name=name
        self.age=age
        self.sex=sex
        self.salary=salary
        self.level=level
        self.courses = []

    def walk(self):
        print('%s is walking'%self.name)

    def teach(self):
        print('%s is teaching'%self.name)

    def tell_info(self):
        print('''
        ----------%s info--------
        NAME:%s
        AGE:%s
        SEX:%s
        SAL:%s
        LEVEL:%s
        '''%(self.name,self.name,self.age,self.sex,self.salary,self.level))

    def tell_course(self):  #self=egon 
        if 'courses' in self.__dict__:  #'courses' in egon.__dict__
            for obj in self.courses:
                obj.tell_course()

class Course:
    def __init__(self,name,price,period):
        self.name=name
        self.price=price
        self.period=period

    def tell_course(self):
        print('''
        ------%s info------
        course name:%s
        course price:%s
        course period:%s
        '''%(self.name,self.name,self.price,self.period))

egon=Teacher('egon',18,'male',30000,10)
python=Course('Python',15800,'6 mons')
linux=Course('Linux',12800,'3 mons')
go=Course('Go',9800,'4 mons')

egon.courses.append(python)
egon.courses.append(go)
egon.tell_course()

我们需要注意一点：

序列化：

import pickle
xiaohuang=Student('xiaohuang',73,'male','group8')
python=Course('Python',15800,'6 mons')
linux=Course('Linux',12800,'3 mons')
go=Course('Go',9800,'4 mons')

xiaohuang.courses.append(python)
xiaohuang.courses.append(go)
res=pickle.dumps(xiaohuang)
print(res)

with open('studentdb.pkl','wb') as f:
    f.write(res)

运行结果：
b'x80x03c__main__
Student
qx00)x81qx01}qx02(Xx04x00x00x00nameqx03X	x00x00x00xiaohuangqx04Xx03x00x00x00ageqx05KIXx03x00x00x00sexqx06Xx04x00x00x00maleqx07Xx05x00x00x00groupqx08Xx06x00x00x00group8q	Xx07x00x00x00coursesq
]qx0b(c__main__
Course
qx0c)x81q
}qx0e(hx03Xx06x00x00x00Pythonqx0fXx05x00x00x00priceqx10Mxb8=Xx06x00x00x00periodqx11Xx06x00x00x006 monsqx12ubhx0c)x81qx13}qx14(hx03Xx02x00x00x00Goqx15hx10MH&hx11Xx06x00x00x004 monsqx16ubeub.'

注意：json不能序列化对象，我们应该用pickle

反序列化：

with open('studentdb.pkl','rb') as f:
    res=f.read()
    obj=pickle.loads(res)
    print(obj)
    obj.tell_info()
运行结果：
        ------Python info------
        course name:Python
        course price:15800
        course period:6 mons
        

        ------Go info------
        course name:Go
        course price:9800
        course period:4 mons

反序列化一定要基于类在内存里面

实现与用户交互：

class Student:
    def __init__(self,name,age,sex,group):
        self.name=name
        self.age=age
        self.sex=sex
        self.group=group
        self.courses = []

    def study(self):
        print('%s is studying'%self.name)

    def tell_info(self):
        print("""
        -------%s info-------
        NAME:%s
        AGE:%s
        SEX:%s
        GROUP:%s
        """%(self.name,self.name,self.age,self.sex,self.group))

    def tell_course(self):
        if 'courses' in self.__dict__:
            for obj in self.courses:
                obj.tell_course()

name=input('user: ').strip()
age=int(input('age: ').strip())
sex=input('sex: ').strip()
group=input('group: ').strip()

xiaohuang=Student(name,age,sex,group)
xiaohuang.tell_info()
运行结果：
user: xiaohuang
age: 73
sex: male
group: group8

        -------xiaohuang info-------
        NAME:xiaohuang
        AGE:73
        SEX:male
        GROUP:group8

简洁的写法：

class Student:
    def __init__(self,name,age,sex,group):
        self.name=name
        self.age=age
        self.sex=sex
        self.group=group
        self.courses = []

    def study(self):
        print('%s is studying'%self.name)

    def tell_info(self):
        print("""
        -------%s info-------
        NAME:%s
        AGE:%s
        SEX:%s
        GROUP:%s
        """%(self.name,self.name,self.age,self.sex,self.group))

    def tell_course(self):
        if 'courses' in self.__dict__:
            for obj in self.courses:
                obj.tell_course()

class Course:
    def __init__(self, name, price, period):
        self.name = name
        self.price = price
        self.period = period

    def tell_course(self):
        print('''
        ------%s info------
        course name:%s
        course price:%s
        course period:%s
        ''' % (self.name, self.name, self.price, self.period))

import pickle
xiaohuang=Student('xiaohuang',18,'male','group8')
with open('studentdb.pkl','wb') as f:
    pickle.dump(xiaohuang,f)

with open('studentdb.pkl','rb') as f:
    obj=pickle.load(f)
    obj.tell_info()
运行结果：
        -------xiaohuang info-------
        NAME:xiaohuang
        AGE:18
        SEX:male
        GROUP:group8
        

模块的运用：

先定义一下几个文件：

各文件内容如下：

models.py:

class Student:
    def __init__(self,name,age,sex,group):
        self.name=name
        self.age=age
        self.sex=sex
        self.group=group
        self.courses = []

    def study(self):
        print('%s is studying'%self.name)

    def tell_info(self):
        print("""
        -------%s info-------
        NAME:%s
        AGE:%s
        SEX:%s
        GROUP:%s
        """%(self.name,self.name,self.age,self.sex,self.group))

pickle_obj.py:

import pickle

def get_obj():
    with open('studentdb.pkl', 'rb') as f:
        res=f.read()
        obj=pickle.loads(res)
        obj.tell_info()

    with open('studentdb.pkl', 'rb') as f:
        obj = pickle.load(f)
        obj.tell_info()

start.py:

from models import Student

import pickle_obj

pickle_obj.get_obj()

还有我们事先准备好的studentdb.pkl文件。

运行start.py文件，效果如下：

        -------xiaohuang info-------
        NAME:xiaohuang
        AGE:18
        SEX:male
        GROUP:group8

接下来看开发软件的规范：

bin文件夹一般放可执行文件，conf文件夹一般放可配置文件，db文件夹一般方法数据文件，还有log目录，lib目录（一般存放常用小工具），src目录放核心，类，逻辑等

开发选课系统：

main函数提供菜单，用户可以选择

今天作业：老师，学生，课程三个类实现选课系统