Python Arbitrary (Variable-Length) Arguments (*args and **kwargs)

In Python, arbitrary arguments (also called variable-length arguments) allow a function to accept any number of inputs.

This is very useful when you don’t know in advance how many values will be passed into a function.

Python provides two types:

• *args → Variable number of positional arguments
• **kwargs → Variable number of keyword arguments

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🔹 What are Arbitrary Arguments?

Arbitrary arguments let a function accept:

✔ Unlimited values
✔ Flexible inputs
✔ Dynamic function calls

Instead of fixed parameters, Python collects them into:

• A tuple (*args)
• A dictionary (**kwargs)

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🔹 1. *args (Arbitrary Positional Arguments)

The *args syntax allows you to pass multiple positional arguments.

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🔹 Syntax of *args

def function_name(*args):
    pass

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🔹 Example of *args

def total(*args):
    print(args)

total(10, 20, 30, 40)

🔸 Output:

(10, 20, 30, 40)

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🔹 Example: Sum of Numbers

def add(*numbers):
    result = sum(numbers)
    print("Sum:", result)

add(5, 10, 15)
add(1, 2, 3, 4, 5)

🔸 Output:

Sum: 30
Sum: 15

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🔹 Loop through *args

def show_items(*items):
    for item in items:
        print(item)

show_items("Apple", "Banana", "Mango")

🔸 Output:

Apple
Banana
Mango

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🔍 Key Point:

• *args is stored as a tuple

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🔹 2. **kwargs (Arbitrary Keyword Arguments)

The **kwargs syntax allows a function to accept any number of keyword arguments.

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🔹 Syntax of **kwargs

def function_name(**kwargs):
    pass

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🔹 Example of **kwargs

def info(**kwargs):
    print(kwargs)

info(name="John", age=25, city="Phnom Penh")

🔸 Output:

{'name': 'John', 'age': 25, 'city': 'Phnom Penh'}

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🔹 Loop through **kwargs

def display(**data):
    for key, value in data.items():
        print(key, ":", value)

display(name="Anna", job="Developer", country="USA")

🔸 Output:

name : Anna
job : Developer
country : USA

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🔍 Key Point:

• **kwargs is stored as a dictionary

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🔹 Real-Life Example: Student System (*args)

def marks(*scores):
    print("Total:", sum(scores))

marks(80, 90, 85)

🔸 Output:

Total: 255

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🔹 Real-Life Example: User Profile (**kwargs)

def profile(**user):
    print("User Profile:")
    for k, v in user.items():
        print(k, ":", v)

profile(name="Sophy", age=22, country="Cambodia")

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🔹 Mixing Normal, *args, and **kwargs

Python allows combining all types:

def demo(a, b, *args, **kwargs):
    print("a:", a)
    print("b:", b)
    print("args:", args)
    print("kwargs:", kwargs)

demo(1, 2, 3, 4, 5, name="Alex", age=30)

🔸 Output:

a: 1
b: 2
args: (3, 4, 5)
kwargs: {'name': 'Alex', 'age': 30}

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🔹 Rule of Order ⚠️

When combining arguments, the order must be:

1. Normal arguments
2. *args
3. **kwargs

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🔹 ❌ Wrong Order Example

def test(**kwargs, *args):
    pass

❌ This will cause an error

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🔹 Why Use *args and **kwargs?

✔ Makes functions flexible
✔ Handles unknown number of inputs
✔ Useful for APIs and libraries
✔ Reduces need for multiple function versions
✔ Improves code scalability

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🔹 Difference Between *args and **kwargs

Feature	*args	**kwargs
Type	Positional arguments	Keyword arguments
Stored as	Tuple	Dictionary
Syntax	*args	**kwargs
Usage	Multiple values	Named values

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🚀 Conclusion

Python arbitrary arguments (*args and **kwargs) make functions extremely powerful and flexible. They allow you to handle dynamic inputs easily without limiting the number of arguments.

They are widely used in:

• APIs
• Frameworks
• Libraries
• Real-world applications