问题描述
如何从课外打印num的值？
class机器人：
def add（self）：
num = 10
a = 56
a = num + a
打印一个
obj1 = Robot（）
obj1.add（）
How to print the value of num from outside the class?
class Robot:
def add(self):
num = 10
a = 56
a = num + a
print a
obj1 = Robot()
obj1.add()
推荐答案
class Robot:
num = 0
def add(self):
self.num = 10
a = 56
a = self.num + a
print a
obj1 = Robot()
obj1.add()
print obj1.num
将'num'声明为类变量，现在可以使用类Robot的对象从类外部访问num的值。
Declare 'num' as class variable, now you can access value of num from outside of class using object of class Robot.
class Robot:
def __init__(self,Num):
self.Num = Num
def func(self):
return self.Num
我已经定义了一个类和一个构造函数。这里'self'表示指向该类本身的指针。所以我分配了我想要操作的值。
请注意：这里Num不是类变量，它是一个实例变量，所以你想要的方式不可能发生。
但是使用'self'我可以访问函数中的变量。
我同意上述两位先生，他们绝对正确。
完成上述事情后，请输入：
I have defined a class and a constructor. Here 'self' means a pointer to that class itself. So i a assigned the value which i wanted to manipulate.
Please note : Here Num is not a class variable it is an instance variable, so the way you want cant happen.
However using 'self' i can access the variable in the function.
I agree to both the above gentlemen, they are absolutely correct.
after doing the above things, type:
r = Robot(20)
现在：
Now:
r.func()
所以你会得到输出： 20
您需要从中学到的是：类变量和实例变量之间的区别。我希望我们的讨论能让你清楚。
谢谢
So you will get the output : 20
What you need to learn from this is: the difference between a class variable and an instance variable. I hope it is clear to you from our discussion.
Thanks
这篇关于在Python中，如何访问类中函数内的变量？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！