十七. python面向对象

#!/usr/bin/python3
class Dog:
    name = "haha"
    def eat(self):
        return "eat food"
# 实例化类
x = Dog()
# 访问类的属性和方法
print("Dog 类的属性 name 为：", x.name)
print("Dog 类的方法 eat 输出为：", x.eat())

结果：

Dog 类的属性 name 为： haha
Dog 类的方法 eat 输出为： eat food

#!usr/bin/python3
class Dog:
    name = "haha10"
    def __init__(self,name):
        self.name = name

x = Dog("12345")
print("name = ", x.name)

结果：

name = 12345

访问私有属性会报错

#!/usr/bin/python3
class people:
    # 定义私有属性,私有属性在类外部无法直接进行访问
    __name = "zhangsan"

# 实例化类
p = people()
print("name = ", p.__name)#这里会报错

结果：

Traceback (most recent call last):
  File "/Users/bytedance/source/builder/builder/handler/test.py", line 10, in
    print("name = ", p.__name)
AttributeError: 'people' object has no attribute '__name'

与私有属性一样，私有方法也不能在外部访问，定义私有方法也是在方法名前面加__，在外部调用私有方法会报错

#!usr/bin/python3
class student():
    def __get_name(self):
        print("student")

x = student()
x.__get_name() #这行会报错

结果：

Traceback (most recent call last):
  File "/Users/bytedance/source/builder/builder/handler/test.py", line 7, in
    x.__get_name() #这行会报错
AttributeError: 'student' object has no attribute '__get_name'

与java一样，Python 同样支持类的继承

#!/usr/bin/python3
class people:
    def get_name(self):
        print("我叫张三")

class student(people):
    pass

s = student()
s.get_name()

结果：

我叫张三

#!usr/bin/python3
class people:
    def get_name(self):
        print("wo shi zhangsan10")

class student(people):
    def get_name(self):
        print("hahahaha")

x = student()
x.get_name()

结果：

hahahaha