The difference between using *args and * * kwargs to call functions in Python

When defining a function, if the number of parameters is not fixed , We want to be able to use a special string to represent Variable length parameters . that You may encounter two variable length parameters , namely *args and **kwargs.

*args and **kwargs Both are variable length parameter collection mechanisms , So let's summarize *args and **kwargs Differences and precautions of calling .

difference 1：

*args Package the parameters passed into the function into a meta Group （tuple） Call the function body

**kwargs Package the parameters passed into the function into a dictionary （dict） Call the function body

Be careful 1：

If the function parameter qi No preceding *, That's an object , If you add *args, Indicates that multiple arguments can be passed in , The passed in parameters are collected A tuple args This object in , If you use * operation , It means to untie , What is returned is Multiple objects !!

Be careful 2：

If used at the same time args,*args and **kwargs, Must be args,*args,**kwargs The order