python - 为什么调用方法时会出现 AttributeError？

Question

在这段代码中，有一个Person类有一个属性name，它在构造对象时被设置。

它应该这样做：

1. 创建类的实例时，属性被正确设置
2. 调用该greeting()方法时，问候语会说明分配的名称。

class Person:
    def __init__(self, name):
        self.name = name
    def greeting(self):
        # Should return "hi, my name is " followed by the name of the Person.
        return "hi, my name is {}".format(self.name) 
    
# Create a new instance with a name of your choice
some_person = "xyz"  
# Call the greeting method
print(some_person.greeting())

它返回了错误：

AttributeError：“str”对象没有属性“greeting”

Answer 1

您只是将变量设置为字符串，而不是Person类。这将使 aPerson的名称xyz改为。

some_person = Person("xyz")

Answer 2

您的some_person变量是str对象的一个​​实例。哪个没有属性greeting。

您的类Person应该先用name变量实例化，然后才能使用 greeting：

some_person = Person(“xyz”)
print(some_person.greeting())
# "hi, my name is xyz”

Answer 3

class Person:
    def __init__(self, name):
        self.name = name
    def greeting(self):
        # Should return "hi, my name is " followed by the name of the Person.
        print("hi, my name is ",self.name)

# Create a new instance with a name of your choice
some_person = Person("Honey")

# Call the greeting method
print(some_person.greeting())

Answer 4

class Person:
def __init__(self, name):
    self.name = name
def greeting(self):
    # Should return "hi, my name is " followed by the name of the Person.
    return name

# Create a new instance with a name of your choice
some_person = Person("Bob")
# Call the greeting method
print(f"hi, my name is {some_person.name}")

Answer 5

#Use str method instead of greeting() method
def __str__(self):
    # Should return "hi, my name is " followed by the name of the Person.
    return "hi, my name is {}".format(self.name) 
some_person = Person("xyz")  
# Call the __str__ method
print(some_person)

Answer 6

class Person:
    def __init__(self, name):
        self.name = name
    def greeting(self):
        # Should return "hi, my name is " followed by the name of the Person.
        return name

# Create a new instance with a name of your choice
some_person =  Person("XYZ")
# Call the greeting method
print(f"hi, my name is {some_person.name}")