<p>我猜您来自java/C背景,可以回答您的问题。您正在尝试将str类型与float连接起来。另外,先将销售金额设置为str,然后设置为浮动是多余的,不需要在此处导入数学库。我为您创建了一个示例类,其中包含一些遵循“Python之禅”和PEP8准则的通用命名约定</p>
<pre><code>class SalesTax:
def __init__(self):
# class variables
self.user_name = None
self.user_quantity_purchased = None
self.user_price = None
self.state_tax = None
self.sales_amount = None
self.calculated_state = None
def ask_user(self):
self.user_name = input("Enter Customer Name: ")
self.user_quantity_purchased = int(input("Enter Quantity Purchased: "))
self.user_price = int(input("Enter Price per Unit: "))
def calculate_tax(self, state_tax: float):
self.state_tax = state_tax
self.sales_amount = float(self.user_quantity_purchased * self.user_price) *
(1 + self.state_tax)
def print_result(self):
print(" ")
print("Here is your Net Sale!")
print(" ")
print("Customer Name: " + self.user_name)
print("Sales Amount: " + str(self.sales_amount))
print("State Tax: " + str(self.state_tax))
example = SalesTax()
example.ask_user()
example.calculate_tax(0.09)
example.print_result()
</code></pre>