Python Decorators Explained
Understand how Python decorators work internally and learn to write your own reusable decorators.
A decorator is a function that wraps another function to extend its behavior without modifying its source.
The mental model
def greet(func):
def wrapper(*args, **kwargs):
print("Before call")
result = func(*args, **kwargs)
print("After call")
return result
return wrapper
@greet
def say_hello():
print("Hello!")Decorators replace the original function object. Use functools.wraps to
preserve its name and docstring for debugging and documentation.
When to use them
- Logging and timing
- Authentication / authorization
- Caching (memoization)
- Retry logic for flaky operations
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