Python Basics · Functions · Lesson 12 of 36
Parameters and Default Values
Concept
Parameters and Default Values
Function parameters can have default values, which are used automatically when no argument is passed.
Parameters with defaults must come after parameters without defaults in the function signature, or Python raises a syntax error.
- Explain the core idea behind Parameters and Default Values.
- Predict output before running a change.
- Test one realistic and one unusual input.
- Use the result to make the next decision.
- 1. Read one concept.
- 2. Change the example.
- 3. Run, compare, and explain.
- 4. Complete the challenge below.
Self-check before continuing
Without looking at the example, describe what changes when you modify one input in Parameters and Default Values. Then reopen the editor and prove your explanation with a small test.
You are ready to continue when you can predict, test, and explain the result.
Your turn
Write a function with a default parameter for a discount percentage.
Ask about this lesson or your next move. The guide explains the path without taking the work away from you.
Ready for the next lesson?
Mark this lesson complete when you have finished the exercise.
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