Python Interview Questions
Python interviews range from simple scripting to complex system architecture. We cover generators, decorators, the Global Interpreter Lock (GIL), and modern asynchronous patterns in Python 3.10+. Prepare with these 1 real-world questions covering beginner to advanced scenarios.
Editorial Integrity
Sourced from real backend and data engineering technical screens.
How do Decorators work in Python?
Simple Answer
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.
Detailed Answer
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)`.
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).
Common Mistake
Forgetting to return the inner wrapper function at the end of the decorator.
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.
Test Your Python Knowledge
Take this quick interactive quiz to see if you retained the key concepts.
Python Mastery Quiz
Question 1 of 1How do Decorators work in Python?
Keep Building Your Python Skills
Interview prep works best when combined with hands-on practice. Use these resources to deepen your understanding and build portfolio projects.