如何使用python中我自己的类中定义的变量正确打印句子

Question

所以我在 python 中创建了一个名为 Pizza 的类，它接受 4 个参数...我希望能够插入参数然后打印它，以便它以一个干净的句子出现。例如，如果我把它放到终端---

from Pizza import Pizza
appetizer = Pizza("Pepperoni", 16, 10.50, 10)
print(appetizer)

我想得到这个结果--- 您的意大利辣香肠披萨直径为 16 英寸，价格 10.5 美元，每个馅饼 10 片

不幸的是，当我打印出变量时，我的代码不断得到这个---

<Pizza.Pizza object at 0x7f17b762f650>

有人知道为什么会这样吗？我的代码如下

class Pizza:
    def __init__(self, name, diameter, price, slices):
        self.name = name
        self.diameter = diameter
        self.price = price
        self.slices = slices
    def myfunc(self):
        print("Your" +  self.name + "pizza has a diameter of" + self.diameter + "inches, a price of" + self.price + "and" + self.slices + "slices per pie")

Answer 1

好问题！可以将对象的名称设为 str 函数：

class Pizza:
    def __init__(self, name, diameter, price, slices):
        self.name = name
        self.diameter = diameter
        self.price = price
        self.slices = slices
    def __repr__(self):
        return "Your {} pizza has a diameter of {} inches, a price of {} and {} slices per pie".format(self.name,self.diameter,self.price,self.slices)


appetizer = Pizza("Pepperoni", 16, 10.50, 10)
print(appetizer)

Answer 2

试试

from Pizza import Pizza
appetizer = Pizza("Pepperoni", 16, 10.50, 10).myfunc()
#you don't need to print appetizer because myfunc does it already

另外，将披萨类更改为此

class Pizza:
    def __init__(self, name, diameter, price, slices):
        self.name = name
        self.diameter = diameter
        self.price = price
        self.slices = slices
    def myfunc(self):
        print("Your " +  self.name + " pizza has a diameter of " + str(self.diameter) + " inches, a price of " + str(self.price) + " and " + str(self.slices) + " slices per pie")

所以它不会导致“TypeError: can only concatenate str (not "int") to str”错误

Answer 3

你告诉 Python 打印 Pizza 对象，所以它很高兴地遵守 :)。同样在您的 myfunc() 方法中，您正在向数字添加字符串（这将导致错误）。

你应该试试这个：

class Pizza:
    def __init__(self, name, diameter, price, slices):
        self.name = name
        self.diameter = diameter
        self.price = price
        self.slices = slices
    def myfunc(self):
        print("Your", self.name, "pizza has a diameter of", self.diameter, "inches, a price of", self.price, "and", self.slices, "slices per pie")

和

from Pizza import Pizza
appetizer = Pizza("Pepperoni", 16, 10.50, 10)
appetizer.myfunc()

输出： Your Pepperoni pizza has a diameter of 16 inches, a price of 10.5 and 10 slices per pie