Python Tips — How to Write Better Functions, Part One

Don’t Over Unpack Function Return Values

When a Python function returns multiple values, it’s common to unpack those values for further use. For example:

def get_student_details():
    # Simulate fetching student details from a database
    student_id = 101
    first_name = "John"
    last_name = "Doe"
    age = 20
    grade = 89
    return student_id, first_name, last_name, age, grade

# Unpack the values returned by the function
student_id, first_name, last_name, age, grade = get_student_details()

# Print the unpacked variables
print("Student ID:", student_id)
print("First Name:", first_name)
print("Last Name:", last_name)
print("Age:", age)
print("Grade:", grade)

There are two problems with the above code.

• First, because there are many return values, so it is all too easy to reorder them accidentally (e.g., swapping age and grade), which can cause bugs that are hard to spot later.
• Second, the line that calls the function and unpacks the values is too long which hurts the readability.

To mitigate these issues, it’s advisable to limit your use of variables when unpacking multiple return values from a function to a maximum of three. This can involve extracting individual values from a three-tuple…