Python Interview Questions (Part 3)
What is GIL in Python?
The Global Interpreter Lock (GIL) in Python is a mutex that allows only one thread to execute in the interpreter at a time. This affects multi-threaded programs, limiting true parallelism. While it can boost performance for single-threaded tasks, it hinders multi-threaded performance on multi-core systems.
Why was the language called Python?
Python is named after the British comedy group "Monty Python." Guido van Rossum, Python's creator, was a fan of the group. The name reflects the language's focus on readability, humor, and simplicity.
Docstrings vs Comments
Docstrings are used to provide documentation for functions, modules, and classes in Python. Unlike comments, docstrings are accessible at runtime using the . __doc__ attribute. They offer a standardized way of documenting code and can be used to generate documentation automatically.
What are Python decorators?
Decorators in Python are functions that modify other functions or methods. They allow you to add functionality to existing code without modifying it directly. Common use cases include logging, access control, and performance measurement.
Is there a switch..case statement in Python?
Python does not have a built-in switch..case statement like some other programming languages. Instead, you can use a dictionary to simulate switch-like behavior, where keys are cases and values are associated actions.
raw_input() VS. input() in Python?
In Python 2, raw_input() reads input as strings, while input() evaluates the input as Python code. In Python 3, input() reads input as strings, and raw_input() is not available.
What is the difference between Xrange and range?
In Python 2, xrange() generates values one at a time and is more memory-efficient for large ranges, while range() creates a list containing all values at once. In Python 3, range() functions like Python 2's xrange().
How to exit Python script in command prompt?
In the command prompt, you can exit a Python script by typing exit() or pressing Ctrl + Z followed by Enter.
Why is Python not fully object-oriented?
Python is not fully object-oriented because it allows procedural programming and supports non-object-oriented constructs. This flexibility enhances Python's ease of use and adaptability to various programming styles.
When is a dictionary used instead of a list?
Dictionaries are used when you need to store data with key-value pairs, allowing efficient retrieval by keys. Lists are used for ordered collections of items. Dictionaries are better suited for scenarios that require efficient lookups and mappings.
What do you mean by list comprehension?
List comprehension is a concise way to create lists in Python by specifying the elements you want in the list, often with a condition or transformation applied to the elements.
What is the Dogpile effect?
The Dogpile effect, also known as the "thundering herd" problem, occurs in caching systems when multiple requests simultaneously expire cached data, causing all requests to trigger a resource-intensive recalculation or database query. This can lead to server overload and decreased performance.