Question

我正在浏览Python Crash Course这本书，我正在努力解决课程问题。我已经复制了书中的代码，我不断收到错误信息，我不确定是不是错了。

class Dog():
    """A simple attempt to model a dog."""

    def __init__(self, name, age):
        """Initialize name and age attributes."""
        self.name = name
        self.name = age

    def sit(self):
        """Simulate a dog sitting in response to a command."""
        print(self.name.title() + " is now sitting.")

    def roll_over(self):
        """Simulate rolling over in response to a command."""
        print(self.name.title() + " rolled over!")


my_dog = Dog('willie', 6)

print("My dog's name is " + my_dog.name.title() + ".")
print("My dog is " + str(my_dog.age) + " years old.")

我不断收到错误消息。

Traceback (most recent call last):
  File "dog.py", line 20, in <module>
    print("My dog's name is " + my_dog.name.title() + ".")
AttributeError: 'int' object has no attribute 'title'

Answer 1

Python对缩进很敏感。所以你的类方法需要像这样缩进：

class Dog():
    def method1():
        ...

    def method2():
        ...

代码很可能是正确缩进的，但你复制并粘贴了格式化文件。

此外，尽管存在缩进问题，但您Dog类没有名为title()的方法。

Answer 2

你的类需要为python编译器缩进。就像你需要缩进函数和循环以及if语句一样，你需要缩进类。所以你班上的顶级应该是这样的。

class Dog():
"""A simple attempt to model a dog."""

    def __init__(self, name, age):
        """Initialize name and age attributes."""
        self.name = name
        self.name = age

Answer 3

我在您的脚本的评论中添加了指出问题以及下面的功能版本。

class Dog():
    """A simple attempt to model a dog."""
#all the methods for class Dog must be indented. Python cares a lot about indents
def __init__(self, name, age):
    """Initialize name and age attributes."""
    self.name = name
    self.name = age #you are setting self.name to age here

def sit(self):
    """Simulate a dog sitting in response to a command."""
    print(self.name.title() + " is now sitting.") #You never create a method called title() for the attribute name. Python won't know what to do with this. 

def roll_over(self):
    """Simulate rolling over in response to a command."""
    print(self.name.title() + " rolled over!") #same problem as above


my_dog = Dog('willie', 6)

print("My dog's name is " + my_dog.name.title() + ".")
print("My dog is " + str(my_dog.age) + " years old.")

这是一个工作版本

class Dog():
    """A simple attempt to model a dog."""

    def __init__(self, name, age):
        """Initialize name and age attributes."""
        self.name = name
        self.age = age 

    def sit(self):
        """Simulate a dog sitting in response to a command."""
        print(self.name + " is now sitting.")

    def roll_over(self):
        """Simulate rolling over in response to a command."""
        print(self.name + " rolled over!")


my_dog = Dog('willie', 6)

print("My dog's name is " + my_dog.name + ".")
print("My dog is " + str(my_dog.age) + " years old.")

.title（）问题是由于您将self.name设置为整数而导致的.title只是字符串上的一种方法。所以如果你想要大写使用

class Dog():
    """A simple attempt to model a dog."""

    def __init__(self, name, age):
        """Initialize name and age attributes."""
        self.name = name
        self.age = age 

    def sit(self):
        """Simulate a dog sitting in response to a command."""
        print(self.name.title() + " is now sitting.")

    def roll_over(self):
        """Simulate rolling over in response to a command."""
        print(self.name.title() + " rolled over!")


my_dog = Dog('willie', 6)

print("My dog's name is " + my_dog.name.title() + ".")
print("My dog is " + str(my_dog.age) + " years old.")

Python Crash Course 9.示例代码

3 个答案: