TypeError：在 Python 中为参数获取了多个值

TypeError: 在 Python 中得到多个参数值

TypeError: got multiple values for argument in Python

当我们在函数调用中用关键字参数覆盖位置参数的值时，会出现 Python“TypeError: got multiple values for argument”。

要解决该错误，请确保只为参数传递一个值一次，并指定self为类方法中的第一个参数。

下面是错误如何发生的示例。

def get_employee(name, **kwargs):
    return {'name': name, **kwargs}


# ⛔️ TypeError: get_employee() got multiple values for argument 'name'
result = get_employee('Alice', name='Alice')
print(result)

该get_employee函数采用name位置参数和关键字参数。

不允许为同一参数指定多个值。

从函数调用中移除关键字参数

name解决错误的一种方法是从函数调用中删除关键字参数。

def get_employee(name, **kwargs):
    return {'name': name, **kwargs}


result = get_employee('Alice')
print(result)  # 👉️ {'name': 'Alice'}

我们只调用了带有参数位置参数的函数name。

仅将值作为关键字参数传递

或者，您可以name仅将参数作为关键字参数传递。

def get_employee(name, **kwargs):
    return {'name': name, **kwargs}


result = get_employee(name='Alice', salary=100)
print(result)  # 👉️ {'name': 'Alice', 'salary': 100}

我们get_employee使用 2 个关键字参数调用该函数，因此 Python 不再对提供参数的值感到困惑。

忘记指定self为类中的第一个参数

Another common cause of the error is forgetting to specify self as the first
argument in a class method.

class Employee():
    # 👇️ forgot to specify `self` as first arg
    def get_name(name=None):
        return name


emp1 = Employee()

# ⛔️ TypeError: Employee.get_name() got multiple values for argument 'name'
emp1.get_name(name='Alice')

We didn’t specify self as the first
argument in the get_name method which caused the error.

self represents an instance of the class, so when we assign a variable as
self.my_var = 'some value', we are declaring an instance variable – a variable
unique to each instance.

You could name this argument anything because the name self has no special
meaning in Python.

# Specify self as the first argument in the method

To solve the error, make sure to specify self as the first argument in the
method.

class Employee():
    # ✅ specified self as first arg
    def get_name(self, name=None):
        return name


emp1 = Employee()

print(emp1.get_name(name='Alice'))  # 👉️ "Alice"

Now that we set self as the first argument in the method, everything works as
expected.

The issue was caused because Python automatically passes the instance (self)
as the first argument to the method.

So, if you don’t explicitly specify the self arg in the definition of the
method, Python passes self and we pass name='Alice' as a value for the same
argument.

class Employee():
    # 👇️ forgot to specify `self` as first arg
    def get_name(name=None):
        return name


emp1 = Employee()

# ⛔️ TypeError: Employee.get_name() got multiple values for argument 'name'
print(emp1.get_name(name='Alice'))

Otherwise, you and Python might end up passing a value for the same argument,
which is very confusing.

请注意，您应该只指定self实例方法（您在类实例上调用的方法）中的第一个参数。

如果你有一个基本函数，你不应该指定一个self参数。