Function Arguments and Return Values

Functions often need inputs to work with. These inputs are called arguments. You can also make functions return values, which you can reuse elsewhere.

Let’s break this down step by step.

1. Positional Arguments

These are the most common. You pass values in the order the function expects them.

def multiply(x, y):
    print("Product:", x * y)

multiply(2, 4)

Explanation:

• x gets 2, y gets 4
• The result printed is Product: 8

2. Return Values

Instead of just printing, functions can send a value back using return.

def multiply(x, y):
    return x * y

result = multiply(2, 4)
print("Result:", result)

Explanation:

• The function calculates the product and returns it.
• We store the result in a variable and print it later.

3. Keyword Arguments

You can also pass values by name, which is more flexible.

def introduce(name, age):
    print(name, "is", age, "years old.")

introduce(age=12, name="Liam")

Explanation:

• You don’t have to follow order if you use names.
• This improves clarity and avoids mistakes.

4. Default Values

Set a default value in the function definition to make arguments optional.

def greet(name="friend"):
    print("Hello,", name)

greet()
greet("Sophie")

Explanation:

• The first call uses the default ("friend").
• The second call overrides it with "Sophie"

Summary

Concept	Description
Positional arguments	Passed in order; e.g., func(2, 3)
Keyword arguments	Passed by name; e.g., func(x=2, y=3)
Default arguments	Optional values in the function definition
return	Sends a value back to the caller

What’s Next?

In the next lesson, we’ll explore variable scope and see what happens when functions are defined inside other functions.