Python Interview Questions
Learn Python structures, decorators, memory management, and practical application logic.
Advanced
How do Decorators work in Python?
A decorator is a function that takes another function and extends its behavior without modifying it explicitly. It allows you to wrap a function with additional logic, like checking if a user is logged in before letting them access a route.
Deep Dive
Because Python functions are first-class citizens (they can be passed as arguments), a decorator takes a function as an argument, defines a wrapper function inside it that executes the additional code (before or after the original function), and then returns the wrapper. We use the `@decorator_name` syntax above a function as syntactic sugar for `func = decorator_name(func)`.
Real World Example: In Flask or FastAPI, you use `@app.route('/home')` to attach routing logic to a function. Or you might use `@login_required` to check authentication before a user can view a dashboard function.
💡 Interview Tip:If asked to write one on a whiteboard, don't forget to use `functools.wraps` inside your decorator to preserve the original function's metadata (like its name and docstring).