Home > Article > Backend Development > A brief discussion on object-oriented programming in python (code examples)
A brief discussion on object-oriented programming in python (code examples)
- 青灯夜游forward
- 2018-10-29 17:36:312787browse
This article brings you a brief discussion of object-oriented programming in python (code examples). It has certain reference value. Friends in need can refer to it. I hope it will be helpful to you.
1. The first case---create a class
#__author:"吉"
#date: 2018/10/27 0027
#function:
# 设计类：
'''
类名：首字母大写，见名思意
属性：驼峰原则
行为：见名思意，驼峰法
说明：类不占空间，实例化对象占用空间！
'''
# 格式,object是父类，超类
'''
类名(object)：
属性
行为
'''
class Peoson(object):
name = 'zhanglei'
age = 24
weight = 70
def run(self):
print("跑！")
def eat(self):
print('吃')
2. Instantiate objects using classes
#__author:"吉"
#date: 2018/10/27 0027
#function:
# 设计类：
'''
类名：首字母大写，见名思意
属性：驼峰原则
行为：见名思意，驼峰法
说明：类不占空间，实例化对象占用空间！
'''
# 格式,object是父类，超类
'''
类名(object)：
属性
行为
'''
class Peoson(object):
name = 'zhanglei'
age = 24
weight = 70
def run(self):
print("跑！")
def eat(self):
print('吃')
def changeName(self,name):
self.name = name
# 实例化对象
'''
格式：对象名= 类名（参数列表信息）
'''
peoson1 = Peoson()
print(peoson1.name,peoson1.age,peoson1.weight)
print(peoson1.eat())
print(peoson1.run())
# 原理
'''
变量是在栈区，对象是在堆区。
'''
3. Accessing the properties and methods of objects
#__author:"吉"
#date: 2018/10/27 0027
#function:
# 设计类：
'''
类名：首字母大写，见名思意
属性：驼峰原则
行为：见名思意，驼峰法
说明：类不占空间，实例化对象占用空间！
'''
# 格式,object是父类，超类
'''
类名(object)：
属性
行为
'''
class Peoson(object):
name = 'zhanglei'
age = 24
weight = 70
def run(self):
print("跑！")
def eat(self):
print('吃')
def changeName(self,name):
self.name = name
# 实例化对象
'''
格式：对象名= 类名（参数列表信息）
'''
peoson1 = Peoson()
# 访问属性
'''
变量是在栈区，对象是在堆区。
'''
print(peoson1.name,peoson1.age,peoson1.weight)
peoson1.name = 'jiji'
peoson1.age = 33
peoson1.weight = 90
print(peoson1.name,peoson1.age,peoson1.weight)
peoson1.changeName('lala')
print(peoson1.name,peoson1.age,peoson1.weight)
4. Constructor
#__author:"吉勇佳"
#date: 2018/10/27 0027
#function:
'''
构造函数：__init__() 是在创建类的时候自动调用，不写出这个
构造函数的话，默认是一个空的构造函数什么页不执行。
'''
class Peoson(object):
def __init__(self,name,age,height,weight):
self.name = name
self.age = age
self.height = height
self.weight = weight
def run(self):
print("跑！")
def eat(self):
print('吃')
def changeName(self,name):
self.name = name
# 实例化对象
p1 = Peoson("jiyongjia",24,177,78)
print(p1.name,p1.age,p1.height,p1.weight)
p1.changeName('zhanglei')
print(p1.name,p1.age,p1.height,p1.weight)
# self 原理
'''
1、哪个对象调用，self就代表那个对象。
'''
5. Use of self.__class__() to create instances and destructors
class Peoson(object):
def __init__(self,name,age,height,weight):
self.name = name
self.age = age
self.height = height
self.weight = weight
# 这里是析构函数
def __del__(self):
print("我是析构函数")
def run(self):
print("跑！")
def eat(self):
print('吃')
def changeName(self,name):
self.name = name
# 创建对象函数 self.__class__ 是代表类名的
def createObj(self,name):
p=self.__class__(name,24,56,89)
print(p.name,p.age,p.weight,p.height)
# 即 执行p1的一个方法即可创建新的对象。
p1 = Peoson("丽丽",33,53,222)
print(p1.name,p1.age,p1.height,p1.weight)
p1.createObj("狗熊")
'''
输出：丽丽 33 53 222
狗熊 24 89 56
我是析构函数
我是析构函数
'''
print(p1.name)
6. Comparison of __str__() and __repr__()
'''
重写
__str__()
str方法是给用户用的，用于返回用户需要的结果信息、
__repr__()
如果换成__repr__()是得到与str相同的结果。是在黑屏终端直接敲对象名再回车的方法
注意：在没有str方法但是有repr的时候，repr 就相当于str，只是repr用于黑屏终端
'''
class Peoson(object):
def __init__(self,name,age,height,weight):
self.name = name
self.age = age
self.height = height
self.weight = weight
# 这里是析构函数
def __del__(self):
print("我是析构函数")
def run(self):
print("跑！")
def eat(self):
print('吃')
def changeName(self,name):
self.name = name
# 创建对象函数 self.__class__ 是代表类名的
def createObj(self,name):
p=self.__class__(name,24,56,89)
print(p.name,p.age,p.weight,p.height)
# 如果换成__repr__()是得到相同的结果。是在黑屏终端直接敲对象名再回车的方法
def __str__(self):
pass
# return "这里是str"
# return self.name
#返回多个值的话用如下
return "%s-%d-%d" % (self.name,self.age,self.weight)
# 如果要打印出所有的属性信息呢？
p1 = Peoson("嘉嘉",44,222,336)
# 不写def __str__()方法的时候，打印出的是该对象的地址信息
print(p1)
'''
输出：9518e65a3214f7b54c5c5a9abe23737f
'''
# 写了__str__()函数是 打印出的自己需要返回的信息数据，此时p1等价于p1.__str__()
print(p1)
7. Exercise-Object-oriented homework:
The gun design bullet design is missing one bullet at a time. If there is no bullet, it will prompt that you cannot shoot.
#__author:"吉"
#date: 2018/10/27 0027
#function:
# 枪设计子弹 设计一次少一个子弹，没子弹了提示无法射击
class Gun(object):
def __init__(self,name,bulletNum):
self.name = name
self.bulletNum = bulletNum
def shot(self):
self.bulletNum =self.bulletNum - 1
if self.bulletNum+1 != 0:
print("此枪型号是：%s,此次射击成功！子弹减少1发，余量为：%d" %(self.name,self.bulletNum))
else:
print("*************射击失败，子弹数为0.已经为您子弹加弹5发！请重新射击！**************")
self.bulletNum = 5
gun = Gun("AK47",5)
# 射击敌人
gun.shot()
gun.shot()
gun.shot()
gun.shot()
gun.shot()
gun.shot()
gun.shot()
gun.shot()
gun.shot()
gun.shot()
gun.shot()
gun.shot()
gun.shot()
'''
输出：
此枪型号是：AK47,此次射击成功！子弹减少1发，余量为：4
此枪型号是：AK47,此次射击成功！子弹减少1发，余量为：3
此枪型号是：AK47,此次射击成功！子弹减少1发，余量为：2
此枪型号是：AK47,此次射击成功！子弹减少1发，余量为：1
此枪型号是：AK47,此次射击成功！子弹减少1发，余量为：0
*************射击失败，子弹数为0.已经为您子弹加弹5发！请重新射击！**************
此枪型号是：AK47,此次射击成功！子弹减少1发，余量为：4
此枪型号是：AK47,此次射击成功！子弹减少1发，余量为：3
此枪型号是：AK47,此次射击成功！子弹减少1发，余量为：2
此枪型号是：AK47,此次射击成功！子弹减少1发，余量为：1
此枪型号是：AK47,此次射击成功！子弹减少1发，余量为：0
*************射击失败，子弹数为0.已经为您子弹加弹5发！请重新射击！**************
此枪型号是：AK47,此次射击成功！子弹减少1发，余量为：4
'''
8. How to create private attributes, in The outside cannot be accessed or modified
#1 Specifies a private attribute that cannot be changed externally: that is, add two underscores in front of the attribute, such as __money
#2 In python, there is only a certain Properties with two underscores in front of them are called private properties, while __money__ is not called a special property.
#3 _money is not a private attribute, but when we see such a variable, we should treat it as private by convention. It is not private in nature, it is accessible.
# 指定私有属性，在外部无法更改:即在属性前加两个下划线 如__money
class Person(object):
def __init__(self,name,age,height,weight,money):
self.name = name
self.age = age
self.height = height
self.weight = weight
self.__money= money
def run(self):
print("跑！")
def eat(self):
print('吃')
def changeName(self,name):
self.name = name
# 创建对象函数 self.__class__ 是代表类名的
def createObj(self,name):
p=self.__class__(name,24,56,89,10000)
print(p.name,p.age,p.weight,p.height,p.__money)
# 即 执行p1的一个方法即可创建新的对象。
p1 = Person("丽丽",33,53,222,20000)
print(p1.name,p1.__money) #此处出错，在外部无法访问私有
If you want to access it from outside, you can put the private properties in the method and call the method to access the private properties. Such as:
def run(self):
print("跑！")
print("工资",self.__money)Summary: When accessing or modifying private attributes, modification and access can be achieved through two fixed methods. At the same time, data can be filtered in the methods.
# 对于处理私有属性的方法---设置值的方法
def SetMoney(self,money):
if money<0:
print("输入的钱不能小于0")
else:
self.__money = money
# 对于访问私有属性的方法
def GetMoney(self):
return self.__money
# In fact, the reason why __money cannot be accessed is because python changed the private attribute to _Person__money,
# that is, it is still accessible. But you should follow the rules and not access it like this.
p1._Person__money = 70 print(p1.GetMoney())
As mentioned above, you can still modify the private attributes.
父类的文件信息：
class People(object):
def __init__(self,name,age):
self.name=name
self.age=age
子类中调用上边的父类
from people import People
class Student(People):
def __init__(self,name,age,faceValue):
# 继承父类的__init__()
super(Student,self).__init__(name,age)
self.faceValue = faceValue
stu = Student("玲",22,100)
print(stu.name,stu.age,stu.faceValue)
输出
玲 22 100
# 总结：
# 我们发现Student类中并无这两个属性信息，这两个属性是调用的父类的__init__中的属性。
# 总结： # 我们发现Student类中并无这两个属性信息，这两个属性是调用的父类的__init__中的属性。The above is the detailed content of A brief discussion on object-oriented programming in python (code examples). For more information, please follow other related articles on the PHP Chinese website!