Args and kwargs

*args and **kwargs are used in a function definition to allow for a variable number of arguments.

*args is used to pass a variable number of non-keyword arguments to a function. The * before args tells Python to treat any additional arguments passed to the function as a tuple. Here's an example:

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

my_function(1, 2, 3)

Click the run button above to see the output.

In this example, the my_function can accept any number of arguments. The *args parameter collects all the arguments passed to the function and stores them as a tuple. We then iterate over the args tuple and print each argument.

One example of the built-in Python function that takes a variable number of arguments is the print function.

print(1, 2)
print(1, 2, 3)

On the other hand, **kwargs is used to pass a variable number of keyword arguments to a function. The ** before kwargs tells Python to treat any additional keyword arguments passed to the function as a dictionary. Here's an example:

def my_function(**kwargs):
    print(kwargs)
    for key, value in kwargs.items():
        print(key, value)

my_function(name="John", age=25)  # Output: name John, age 25

In this example, the my_function can accept any number of keyword arguments. The **kwargs parameter collects all the keyword arguments passed to the function and stores them as a dictionary. We can then iterate over the kwargs dictionary and print each key-value pair.

Both *args and **kwargs provide flexibility when working with functions that need to handle a variable number of arguments. They allow us to write functions that can accept different numbers of arguments without explicitly defining them in the function signature.

Note that *args and **kwargs are just naming conventions and can be replaced with any valid variable name. The * and ** symbols are what make them special and indicate their purpose.