Python Developer interview questions focus on Python programming concepts, libraries, frameworks, data structures, and problem-solving skills. Here are 25 common questions with answers to help you prepare.
Q1. What are Python’s key features?
Python is interpreted, dynamically typed, easy to read, supports multiple programming paradigms, has automatic memory management, and offers a large standard library.
Q2. What is PEP 8?
PEP 8 is the Python Enhancement Proposal that provides guidelines and best practices for writing readable Python code.
Q3. How is memory managed in Python?
Python uses private heap space for memory management and has an inbuilt garbage collector to recycle unused memory.
Q4. What are Python decorators?
Decorators are functions that modify the behavior of another function or method without changing its code.
Q5. What is a lambda function?
A lambda function is an anonymous, inline function defined with the lambda keyword, usually for short, simple functions.
Q6. What are Python’s data types?
Common data types include int, float, str, list, tuple, set, dict, and bool.
Q7. How is exception handling done in Python?
Using try, except, else, and finally blocks to catch and handle exceptions gracefully.
Q8. What is the difference between list and tuple?
Lists are mutable (can be changed), whereas tuples are immutable (cannot be changed).
Q9. How do you manage packages in Python?
Using pip, the package installer for Python, to install, upgrade, and manage packages.
Q10. What is the Global Interpreter Lock (GIL)?
GIL is a mutex that protects access to Python objects, preventing multiple native threads from executing Python bytecodes simultaneously.
Q11. What are Python generators?
Generators are functions that return an iterator and yield values one at a time using the yield keyword.
Q12. What are list comprehensions?
List comprehensions provide a concise way to create lists using a single line of code.
Q13. How is multithreading different from multiprocessing in Python?
Multithreading runs threads in the same process sharing memory, while multiprocessing runs separate processes with independent memory spaces.
Q14. What is the difference between shallow copy and deep copy?
Shallow copy copies object references, while deep copy copies the objects recursively.
Q15. What is a Python module and package?
A module is a single Python file; a package is a collection of modules organized in directories with __init__.py files.
Q16. How do you handle file operations in Python?
Using open() function with modes like ‘r’, ‘w’, ‘a’ for reading, writing, and appending files.
Q17. What is the difference between is and == in Python?
is checks object identity (if both refer to the same object), while == checks value equality.
Q18. What are Python’s built-in data structures?
Lists, tuples, sets, and dictionaries.
Q19. How do you implement inheritance in Python?
By defining a new class that inherits from a parent class inside parentheses: class Child(Parent):
Q20. What are Python’s iterators?
Objects that implement __iter__() and __next__() methods to iterate over a sequence of values.
Q21. How do you manage virtual environments in Python?
Using tools like venv or virtualenv to create isolated Python environments.
Q22. What is the difference between xrange and range?
In Python 2, xrange returns an iterator and is more memory efficient, while range returns a list. In Python 3, range behaves like xrange.
Q23. What is the purpose of the pass statement?
pass is a null statement used as a placeholder when a statement is syntactically required but no action is needed.
Q24. How do you perform unit testing in Python?
Using the unittest module or third-party libraries like pytest to write and run tests.
Q25. What are Python’s standard libraries?
Examples include os, sys, math, datetime, json, re, and subprocess, providing a wide range of utilities.