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40. *args and **kwargs

1. Introduction​

*args and **kwargs let functions accept an arbitrary number of positional and keyword arguments respectively.

2. Using *args (Positional Varargs)​

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

print(add_numbers(1, 2, 3, 4))  # 10

3. Using **kwargs (Keyword Varargs)​

def print_info(**kwargs):
    for key, value in kwargs.items():
        print(key, '=', value)

print_info(name='Alice', age=30)

4. Mixing Positional, *args, Defaults, **kwargs​

Parameter order: positional, *args, default parameters, **kwargs.

def func(a, *args, b=10, **kwargs):
    print(a, args, b, kwargs)

func(1, 2, 3, b=20, x=99)

5. Unpacking with * and **​

You can unpack sequences and dicts when calling functions:

nums = [1, 2, 3]
print(add_numbers(*nums))  # unpacks list into positional args

options = {'name': 'Bob', 'age': 25}
print_info(**options)  # unpacks dict into keyword args

6. Practical Example​

def shopping_cart(*items, **details):
    print('Items:', items)
    print('Details:', details)

shopping_cart('apple', 'banana', payment='card', discount=True)

7. Next Steps​

✅ You now understand *args and **kwargs.
Next chapter: Scope and lifetime of variables.