*args And **kwargs In Python

In Python, *args and **kwargs allow functions to accept a variable number of arguments. *args is used for positional arguments, passed as a tuple, while **kwargs handles keyword arguments, passed as a dictionary. This flexibility facilitates the creation of versatile functions that can adapt to a wide range of input parameters.

What Is Python *args?

Python *args is a mechanism in function definitions that allows you to pass a variable number of positional arguments. You use *args in the parameter list of a function to denote that the function can accept any number of positional arguments beyond those already named. The arguments passed to the function are accessible as a tuple within the function body.

For example, consider a function designed to sum any number of numbers.

def sum_numbers(*args):
    return sum(args)

print(sum_numbers(1, 2, 3))
print(sum_numbers(1, 2, 3, 4, 5))

Output:

6
15

In this code, sum_numbers can take any number of arguments, thanks to *args, and calculates their sum.

What Is Python **kwargs?

Python **kwargs is a parameter that allows a function to accept an arbitrary number of keyword arguments. These arguments are passed into the function as a dictionary, enabling dynamically handling named arguments.

For example, consider a function that needs to handle different attributes of a profile.

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

create_profile(name="John Doe", age=30, profession="Developer")

Output:

name: John Doe
age: 30
profession: Developer

In this code, **kwargs collects any number of named arguments passed to create_profile and prints out each key-value pair.

Using Both *args And **kwargs In Python To Call A Function

Using both *args and **kwargs in Python to call a function enables passing a variable number of arguments to a function. This flexibility makes your functions adaptable to various input scenarios.

def function_example(*args, **kwargs):
    print("Positional arguments:", args)
    print("Keyword arguments:", kwargs)

function_example(1, 2, 3, name='Alice', job='Engineer')

Output:

Positional arguments: (1, 2, 3)
Keyword arguments: {'name': 'Alice', 'job': 'Engineer'}

Using *args and **kwargs In Python To Set Values Of Object

Using *args and **kwargs in Python allows for flexible assignment of values to objects. This flexibility is beneficial in object-oriented programming when initializing object attributes.

For instance, *args can be used to pass multiple values to set up various attributes of an object in a single go. Consider a class Book where we want to assign attributes dynamically.

class Book:
    def __init__(self, *args):
        self.title, self.author, self.year = args

book = Book("The Great Gatsby", "F. Scott Fitzgerald", 1925)
print(book.title, book.author, book.year)

Output:

The Great Gatsby F. Scott Fitzgerald 1925

Similarly, **kwargs allows for keyword argument passing, offering a more readable way to initialize object attributes.

class Book:
    def __init__(self, **kwargs):
        self.title = kwargs.get('title')
        self.author = kwargs.get('author')
        self.year = kwargs.get('year')

book = Book(title="1984", author="George Orwell", year=1949)
print(book.title, book.author, book.year)

Output:

1984 George Orwell 1949

These approaches show how *args and **kwargs provide versatility in handling object attributes, making code more adaptable and readable.