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10. Decorator Use Cases

Decorators are widely used in real-world Python projects.

Logging​

def log(func):
    def wrapper(*args, **kwargs):
        print(f"Calling {func.__name__}")
        return func(*args, **kwargs)
    return wrapper

Authentication​

In web frameworks like Flask:

@app.route("/admin")
@login_required
def admin_dashboard():
    ...

Memoization​

from functools import lru_cache

@lru_cache(maxsize=None)
def fib(n):
    if n < 2: return n
    return fib(n-1) + fib(n-2)

Practice Challenge​

Write a timer decorator that measures how long a function takes to run.

Wrap-Up​

  • Decorators are powerful for logging, authentication, caching, and timing.