Python *args and **kwargs Explained (Beginner-Friendly Guide)

If you’re learning Python, you’ve probably seen functions with *args and **kwargs. At first, they look strange — but actually, they’re just tools to make your functions more flexible and powerful.

In this post, we’ll break them down in plain English, with examples and real-world use cases.

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🔹 What is *args?

*args allows a function to accept any number of positional arguments (without needing to define them one by one).
Inside the function, they are collected into a tuple.

👉 Example:

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

print(add_numbers(1, 2, 3))       # 6
print(add_numbers(10, 20, 30, 40)) # 100

Here:

• args = (1, 2, 3)
• args = (10, 20, 30, 40)

✅ When to use?

• When you don’t know how many inputs your function will get.
• Example: calculators, math operations, loggers.

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🔹 What is **kwargs?

**kwargs allows a function to accept any number of keyword arguments (name=value).
Inside the function, they are collected into a dictionary.

👉 Example:

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

show_profile(name="Alice", age=25, country="Indonesia")

Output:

name: Alice
age: 25
country: Indonesia

Here:

• kwargs = {"name": "Alice", "age": 25, "country": "Indonesia"}

✅ When to use?

• When you want flexible options or settings.
• Example: user profiles, API parameters, configuration.

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🔹 Real-World Use Cases

1. Logging System with *args

A logger function where you don’t know how many messages you’ll receive.

def log_message(*args):
    print("LOG:", " ".join(map(str, args)))

log_message("Error:", 404, "Not Found")
log_message("User", "Alice", "logged in")

Output:

LOG: Error: 404 Not Found
LOG: User Alice logged in

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2. Database Connection with **kwargs

Easily handle default settings + overrides.

def connect_db(**kwargs):
    defaults = {"host": "localhost", "port": 5432}
    defaults.update(kwargs)
    print("Connecting with:", defaults)

connect_db(user="admin", password="123")
connect_db(host="db.server.com", user="root")

Output:

Connecting with: {'host': 'localhost', 'port': 5432, 'user': 'admin', 'password': '123'}
Connecting with: {'host': 'db.server.com', 'port': 5432, 'user': 'root'}

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3. API Request with Both

Combine them when you need both positional and keyword arguments.

def api_request(*args, **kwargs):
    print("Method & URL:", args)
    print("Options:", kwargs)

api_request("GET", "/users", auth="token123", timeout=5)

Output:

Method & URL: ('GET', '/users')
Options: {'auth': 'token123', 'timeout': 5}

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🔹 Easy Analogy

• *args → “Bring me items in a bag 📦 (order matters).”
• **kwargs → “Bring me items with labels 🏷️ (names matter).”

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✅ Takeaway

• Use *args when you need a function with flexible positional inputs.
• Use **kwargs when you need flexible named options.
• Together, they make your functions more reusable and adaptable.

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🔥 Next time you see *args and **kwargs, remember:
They’re just Python’s way of saying —
“Don’t worry about the number of inputs, I can handle it.”

Related: Web Scraping with Beautiful Soup: A Beginner’s Guide.

Related: Building a PostgreSQL AI Agent in 200 Lines of Python.