Introduction

In Python, *args and **kwargs are used to pass a variable number of arguments to functions. They allow you to handle function arguments more flexibly, making your functions more versatile and easier to manage.

• *args: Used to pass a variable number of non-keyword arguments (positional arguments) to a function.
• **kwargs: Used to pass a variable number of keyword arguments (named arguments) to a function.

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1. Using *args

Definition

*args allows a function to accept any number of positional arguments. The arguments passed through *args are captured as a tuple.

Syntax:

def function_name(*args):
    # Function body

Example:

def print_fruits(*args):
    for fruit in args:
        print(fruit)

print_fruits("apple", "banana", "cherry")

Output:

apple
banana
cherry

Real-world Example:

Dodagatta Nihar uses *args to handle multiple scores in a grading function:

def calculate_average(*scores):
    return sum(scores) / len(scores)

average_score = calculate_average(85, 90, 78, 92)
print(f"Average Score: {average_score}")

Output:

Average Score: 86.25

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2. Using **kwargs

Definition

**kwargs allows a function to accept any number of keyword arguments. The arguments passed through **kwargs are captured as a dictionary.

Syntax:

def function_name(**kwargs):
    # Function body

Example:

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

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

Output:

name: John
age: 30
city: New York

Real-world Example:

Harsha uses **kwargs to create a profile with various details:

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

create_profile(name="Harsha", profession="Engineer", location="Bangalore")

Output:

name: Harsha
profession: Engineer
location: Bangalore

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3. Combining *args and **kwargs

You can use *args and **kwargs together in a function to handle both positional and keyword arguments. *args must appear before **kwargs in the function definition.

Syntax:

def function_name(*args, **kwargs):
    # Function body

Example:

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

display_info("apple", "banana", fruit_count=2, location="fruit basket")

Output:

Positional arguments: ('apple', 'banana')
Keyword arguments: {'fruit_count': 2, 'location': 'fruit basket'}

Real-world Example:

Vasanta Kumar uses both *args and **kwargs to log user activities:

def log_activity(user_id, *activities, **metadata):
    print(f"User ID: {user_id}")
    print("Activities:", activities)
    print("Metadata:", metadata)

log_activity(101, "login", "view_profile", "logout", timestamp="2024-09-17", session_id="XYZ123")

Output:

User ID: 101
Activities: ('login', 'view_profile', 'logout')
Metadata: {'timestamp': '2024-09-17', 'session_id': 'XYZ123'}

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Few more examples

Example 1: Function with *args

def concat_strings(*args):
    return " ".join(args)

result = concat_strings("Hello", "world", "from", "Python")
print(result)

Output:

Hello world from Python

Example 2: Function with **kwargs

def summarize_data(**kwargs):
    summary = ""
    for key, value in kwargs.items():
        summary += f"{key}: {value}\n"
    return summary

summary = summarize_data(name="Alice", age=28, city="Paris")
print(summary)

Output:

name: Alice
age: 28
city: Paris

Example 3: Function with *args and **kwargs

def report_data(*args, **kwargs):
    print("Arguments:", args)
    print("Keyword arguments:", kwargs)

report_data(1, 2, 3, name="Bob", status="active")

Output:

Arguments: (1, 2, 3)
Keyword arguments: {'name': 'Bob', 'status': 'active'}

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