Return multiple values from a function in Python

A Python function can return several values at once. Write them after return separated by commas, and unpack them into separate variables when you call the function.

The program

def stats(numbers):
    lowest = min(numbers)
    highest = max(numbers)
    average = sum(numbers) / len(numbers)
    return lowest, highest, average

low, high, avg = stats([12, 45, 7, 30, 21])
print(f"Min: {low}, Max: {high}, Average: {avg}")

Min: 7, Max: 45, Average: 23.0

How it works

• return lowest, highest, average returns one tuple with three items. The commas make the tuple; brackets are not needed.
• low, high, avg = ... is tuple unpacking. The number of names on the left must match the number of items, or Python raises a ValueError.
• If you do not unpack, you get the tuple itself:

def stats(numbers):
    return min(numbers), max(numbers), sum(numbers) / len(numbers)

result = stats([12, 45, 7, 30, 21])
print(result)
print(type(result))

(7, 45, 23.0)
<class 'tuple'>

An empty list

min() of an empty list raises a ValueError, and len() would be 0 in the division. Check for that case first and return a clear result:

def stats(numbers):
    if not numbers:
        return None, None, None
    return min(numbers), max(numbers), sum(numbers) / len(numbers)

print(stats([]))
print(stats([5]))

(None, None, None)
(5, 5, 5.0)

When a function returns many values, or the order is easy to forget, a dictionary or a dataclass with named fields is easier to read than a long tuple.