Functions & basics
Reusable building blocks — parameters, returns, scope, and clear function design.
How to Parse Function Parameters with Defaults in Python
Create Python functions with default parameter values to make arguments optional and provide sensible fallbacks.
def greet(name, greeting="Hello", punctuation="!"):
"""Greet a person with customizable greeting and punctuation."""
return f"{greeting}, {name}{punctuation}"
def describe_fruit(fruit, color="unknown", ripe=False):
"""Describe a fruit with optional attributes."""
status = "ripe" if ripe else "not ripe…How to Read Environment Variables in Python with Default Values
Retrieve an environment variable safely using os.getenv() with a fallback default when the variable is missing.
import os
database_url = os.getenv("DATABASE_URL", "postgresql://localhost:5432/mydb")
print(f"Database URL: {database_url}")How to use function defaults in Python
Define Python functions with default parameter values so callers can omit arguments and use sensible fallbacks.
def greet(name="Guest", greeting="Hello", punctuation="!"):
"""Return a greeting message using default parameters."""
return f"{greeting}, {name}{punctuation}"
def describe_pet(pet_name, animal_type="dog"):
"""Display information about a pet with a default animal type."""
print(f"I have a {animal_type…Browse by section
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Functions & basics — Python code examples
What you will find here
This page collects functions & basics snippets — short, copy-ready Python you can paste into our free online IDE and run without installing anything. Each sample includes a plain-English explanation and the full source code.
Samples vs tutorials and challenges
Samples are quick reference — one concept per page. For step-by-step teaching, use our Python tutorials. To test yourself, try quizzes or coding challenges. Clean up style with the Python formatter.