Python Tuples: Return Related Values from a Function

A sales calculation returns the total and the discount as a pair.

What You Need to Understand

A function can return a tuple of related values, and the caller can unpack them into meaningful variables. This avoids storing intermediate results in unrelated global variables.

When to Use It

A sales calculation returns the total and the discount as a pair.

Step-by-Step Python Example

def calculate_total(price, discount_rate):
    discount_amount = price * discount_rate
    return price - discount_amount, discount_amount

final_price, discount = calculate_total(80, 0.1)
print(final_price)
print(discount)

How the Example Works

The function returns one two-item tuple; unpacking assigns its parts to the two names.

Example Output

72.0
8.0
(2, 7)

A Second Example

Compare this smaller variation with the main example, then experiment with your own values.

def bounds(values):
    return min(values), max(values)

print(bounds([3, 7, 2]))

Important Behavior and Edge Cases

The caller must expect the correct number of returned values. Use a named record when many fields could make positional meanings unclear.

Try It Yourself

Write a function returning both the minimum and maximum of a nonempty list.

Common Beginner Mistakes

The caller must expect the correct number of returned values. Use a named record when many fields could make positional meanings unclear.
Overlooking how an iterable is consumed, how element positions are chosen, or whether a function creates a new list.

Key Takeaways

A function can return a tuple of related values, and the caller can unpack them into meaningful variables.
The function returns one two-item tuple; unpacking assigns its parts to the two names.
The caller must expect the correct number of returned values.