Python ... takes 0 positional arguments but 1 was given

news2024/10/5 15:26:41

最近，博主在学习python时遇到这么个报错，

系统：windows10

开发环境：VS Code

Python版本：3.12

错误重现：

class Dog:
    def __init__(self):
        pass

    def eatSomething(self):
        self.eatBone()

    def eatBone():
        print("eat bone...")

    def eatMeat():
        print("eat meat...")

dog  = Dog()
dog.eatSomething()

报错：

Traceback (most recent call last):
  File "e:\ProjectWorkSpace\PythonProgram\PythonCodeInVsCode\python_work\Chapter15\test.py", line 15, in <module>
    dog.eatSomething()
  File "e:\ProjectWorkSpace\PythonProgram\PythonCodeInVsCode\python_work\Chapter15\test.py", line 6, in eatSomething
    self.eatBone()
TypeError: Dog.eatBone() takes 0 positional arguments but 1 was given

意思就是说，eatBone()这个方法没有参数，但在调用该方法时传递了一个参数。

可博主明明没有传递参数呀！

查看官网解释：

Python3.12文档官网连接

意思是说，类中的函数在被调用时，会自动多一个self的参数，就是类本身。因此，在类中的函数定义时要显式地加一个self参数。

如eatSomething(self)方法。

修改程序：

class Dog:
    def __init__(self):
        pass

    def eatSomething(self):
        self.eatBone()

    def eatBone(self):
        print("eat bone...")

    def eatMeat(self):
        print("eat meat...")

dog  = Dog()
dog.eatSomething()
dog.eatMeat()

结果：