What are *args and **kwargs

In Python, *args and **kwargs are commonly used terms that are used to pass a variable number of arguments to a function. Both *args and **kwargs are special syntaxes that allow you to pass a variable number of arguments to a function, without explicitly defining them in the function definition.

*args is short for "arguments" and is used to pass a variable number of non-keyword arguments to a function. On the other hand, **kwargs is short for "keyword arguments" and is used to pass a variable number of keyword arguments to a function.

Using *args and **kwargs can be very useful when you want to create a flexible function that can handle different numbers of arguments or keyword arguments.

How to Use *args

To use *args, simply include an asterisk before the parameter name in the function definition. This tells Python that any additional positional arguments should be collected into a tuple and passed into the function as the parameter value.

Here is an example of a function that accepts *args:

def sum_numbers(*args):
    total = 0
    for number in args:
        total += number
    return total

In this example, the sum_numbers function takes any number of arguments and sums them together. For instance, you can call this function with different numbers of arguments:

print(sum_numbers(1, 2, 3))  # Output: 6
print(sum_numbers(1, 2, 3, 4, 5))  # Output: 15
print(sum_numbers(2, 4, 6, 8, 10, 12))  # Output: 42

As you can see, *args allows the function to handle a varying number of arguments without having to define each one explicitly in the function definition.

How to Use **kwargs

To use **kwargs, you need to define a parameter with two asterisks (**) in the function signature. This parameter will then receive a dictionary of all keyword arguments passed to the function.

Here's an example of how to use **kwargs in Python:

def my_function(\*\*kwargs):
for key, value in kwargs.items():
print(f"{key}: {value}")

my_function(name="John", age=30, city="New York")

In this example, we define a function my_function that takes a variable number of keyword arguments using the **kwargs syntax. The function then loops over the dictionary of keyword arguments using the .items() method, printing out each key-value pair.

When we call the function with my_function(name="John", age=30, city="New York"), the output will be:

name: John
age: 30
city: New York

You can also pass a dictionary to a function that uses kwargs by using the double asterisk () syntax to unpack the dictionary. Here's an example:

def my_function(**kwargs):
    for key, value in kwargs.items():
        print(f"{key}: {value}")

my_dict = {"name": "John", "age": 30, "city": "New York"}
my_function(**my_dict)

In this example, we define a dictionary my_dict with three key-value pairs. We then call the my_function with the double asterisk (**) syntax to unpack the dictionary and pass its contents as keyword arguments to the function.

When we run the code, we get the same output as before:

name: John
age: 30
city: New York