简单类 --> 类属性更新答案

【问题标题】：Simple Class --> Class property updation简单类 --> 类属性更新
【发布时间】：2017-08-22 12:57:07
【问题描述】：

我有一个简单的课程。这是我得到的输出：

>>> print(Customer.total_amount)
1300

但我预计输出是：

>>> print(Customer.total_amount)
1000

我做错了什么？

class Customer:
    total_amount = 0

    def __init__(self, name, mob, email, amount=None):
        self.name = name
        self.mob = mob
        self.eamil = email
        self.amount = 0

    def add_amount(self, amount):
        self.amount += amount
        Customer.total_amount += self.amount

cust1 = Customer("cust1", "8892398598", "ritheshb1@gmail.com")
cust2 = Customer("cust2", "8892498598", "ritheshb2@gmail.com")
cust1.add_amount(100)
cust2.add_amount(200)
cust1.add_amount(300)
cust2.add_amount(400)

print(cust1.amount)
print(cust2.amount)
print(Customer.total_amount)

【问题讨论】：

但实例输出得到正确输出：print(cust1.amount) = 400, print(cust2.amount) = 600
那你为什么要添加self.amount（刚刚在前一行更改了）？

标签： python class

【解决方案1】：

改变：

Customer.total_amount += self.amount

到

Customer.total_amount += amount

【讨论】：