How Do Variable Argument Lists Work in Python?

Variable Argument Lists in Python

In Python, it is possible to create functions that accept a variable number of arguments. This is achieved by using the asterisk (*) operator followed by the argument name, like this:

def varargs_function(*args):
    # Code to handle variable arguments

The argument *args is a special variable that will receive a tuple containing all the arguments passed to the function. For example, if you call the function like this:

varargs_function(1, 2, 3, 4, 5)

The *args variable will contain the tuple (1, 2, 3, 4, 5).

Note that the *args argument must be the last argument in the function signature, or Python will raise a SyntaxError.

Unpacking Arguments

The *args variable contains a tuple of the arguments, but you may want to unpack them into individual variables. This can be done by using the splat operator (*):

def varargs_function(*args):
    for arg in args:
        print(arg)

This example will print each argument on a separate line.

Keyword Arguments

Keyword arguments are arguments that are passed to a function by name. They are denoted by a colon (:) followed by the keyword, like this:

def keyword_args_function(**kwargs):
    # Code to handle keyword arguments

The **kwargs argument is a special variable that will receive a dictionary containing all the keyword arguments passed to the function. For example, if you call the function like this:

keyword_args_function(name="John", age=30)

The **kwargs variable will contain the dictionary {'name': 'John', 'age': 30}.

Combining Varargs and Keyword Arguments

You can combine varargs and keyword arguments in a single function by using the following syntax:

def combined_args_function(*args, **kwargs):
    # Code to handle both varargs and keyword arguments

The varargs argument must be placed before the keyword arguments in the function signature.

Conclusion

Variable argument lists in Python are a powerful feature that allows you to create functions that can accept any number or type of arguments, making them highly flexible and reusable.

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