How would you create a decorator to measure the execution time of a function?
- By adding timestamps manually at the beginning and end of the function.
- By using the @timer decorator.
- By wrapping the function with timeit module functions.
- Python does not support measuring execution time with decorators.
You can create a decorator to measure execution time by adding timestamps manually at the start and end of the function, then calculating the time elapsed. This allows you to track how long a function takes to execute.
How would you create an instance of a metaclass in Python?
- Metaclasses are instantiated automatically when you define a class.
- Use the create_metaclass_instance() function.
- Use the metainstance() method.
- You cannot create an instance of a metaclass.
In Python, you typically do not create instances of metaclasses directly. Metaclasses are instantiated automatically when you create a new class by inheriting from them. Attempting to create an instance of a metaclass directly is not a common practice.
How would you define a class variable that is shared among all instances of a class in Python?
- As a global variable outside the class
- As a local variable inside a method
- Inside the constructor method using self
- Outside of any method at the class level
In Python, you define a class variable outside of any method, directly within the class, and it is shared among all instances of the class. It is accessible as ClassName.variable_name.
How would you define a function in Python that takes no parameters and has no return statement?
- def my_function():
- def my_function(None):
- def my_function(param1, param2):
- def my_function(void):
In Python, you define a function using the def keyword, followed by the function name and parentheses, even if it takes no parameters. For a function with no return statement, it implicitly returns None.
How would you deploy a Django application to a production environment, considering scalability and security?
- Deploy the Django application without a reverse proxy. Implement security measures within Django views and models. Use a basic firewall.
- Host the application on a shared hosting platform. Use self-signed certificates for SSL/TLS. Deploy only a single server instance. Enable root access for easier management.
- Use a single server with Docker containers for isolation. Disable SSL/TLS for faster performance.
- Use a web server like Nginx or Apache as a reverse proxy in front of Gunicorn or uWSGI. Implement SSL/TLS for secure communication. Utilize a load balancer to distribute traffic across multiple server instances. Harden the server by following security best practices.
Deploying a Django application for production involves multiple steps, including setting up a reverse proxy, securing communications with SSL/TLS, load balancing for scalability, and following security best practices.
How would you design a class that shouldn’t be instantiated?
- By declaring the class as abstract.
- By defining a private constructor.
- By making the class private.
- By using the final keyword.
To prevent a class from being instantiated, you can define a private constructor. When the constructor is private, it cannot be called from outside the class, effectively preventing object creation.
How would you enable Cross-Origin Resource Sharing (CORS) in a Flask application?
- CORS is enabled by default in Flask
- Modify the browser's settings
- Use the "@cross_origin" decorator
- Use the Flask-CORS extension
You can enable CORS in Flask by using the Flask-CORS extension. The other options are not the recommended way to enable CORS in Flask.
How would you enable Cross-Origin Resource Sharing (CORS) in a Flask application?
- Add Access-Control-Allow-Origin header to each route manually.
- CORS is not applicable to Flask applications.
- Set CORS_ENABLED = True in the Flask app configuration.
- Use the @cross_origin decorator from the flask_cors extension.
To enable CORS in a Flask application, you typically use the @cross_origin decorator provided by the flask_cors extension. This allows you to control which origins are allowed to access your API.
How would you ensure that a piece of code in a module is only executed when the module is run as a standalone program and not when it is imported?
- #execute_if_standalone
- #only_run_when_main
- #standalone_code
- if name == "main":
To ensure that a piece of code in a Python module is only executed when the module is run as a standalone program and not when it is imported, you can use the special if __name__ == "__main__": conditional statement. Code inside this block will only run when the module is the main entry point of the program.
How would you find the loop in a linked list?
- Iterate through the list and check for a null reference
- Use a hash table to store visited nodes
- Use a stack to track visited nodes
- Use Floyd's Tortoise and Hare algorithm
Floyd's Tortoise and Hare algorithm is a popular technique to detect a loop in a linked list. It involves two pointers moving at different speeds through the list. If there's a loop, they will eventually meet. The other options are not efficient for loop detection.