Python Interview Questions

Python is one of the most popular programming languages in the tech world, used for web development, data analysis, machine learning, and more. To ace your Python interview, you need a solid understanding of core concepts, advanced features, and practical applications.

This guide covers frequently asked Python interview questions, grouped by difficulty level: Beginner, Intermediate, and Advanced.

Beginner-Level Python Questions

1. What is Python?

Python is a high-level, interpreted programming language with dynamic typing and a rich standard library. It is known for its simplicity and readability.

2. What are the key features of Python?

  • Easy to learn and use
  • Extensive libraries and frameworks
  • Open-source and community-driven
  • Platform-independent
  • Supports multiple programming paradigms

3. What are Python’s built-in data types?

  • Numeric: int, float, complex
  • Sequence: list, tuple, range
  • Text: str
  • Set Types: set, frozenset
  • Mapping: dict
  • Boolean: bool

4. What is the difference between a list and a tuple?

  • List: Mutable and ordered.
  • Tuple: Immutable and ordered.

5. What are Python’s built-in functions?

Some commonly used functions include:

  • print(), len(), type(), input()
  • int(), str(), float()
  • sum(), sorted(), zip(), range()

Intermediate-Level Python Questions

6. What is the difference between shallow copy and deep copy?

  • Shallow Copy: Creates a new object but copies the references to the objects inside.
  • Deep Copy: Creates a new object and recursively copies all objects inside it.

7. What is a Python decorator?

A decorator is a function that modifies the behavior of another function or method.
Example:

def decorator_function(func):
    def wrapper():
        print("Before function call")
        func()
        print("After function call")
    return wrapper

@decorator_function
def my_function():
    print("Hello, World!")

my_function()

8. Explain Python’s with statement.

The with statement is used for resource management, such as handling files.
Example:

with open("example.txt", "r") as file:
    content = file.read()

9. How does Python handle memory management?

Python uses reference counting and a cyclic garbage collector to manage memory and clean up unreferenced objects.

10. What are Python modules and packages?

  • Module: A single Python file with .py extension containing code.
  • Package: A directory containing a collection of modules, with an __init__.py file.

Advanced-Level Python Questions

11. What is the Global Interpreter Lock (GIL)?

The GIL is a mutex that protects access to Python objects. It allows only one thread to execute Python bytecode at a time, limiting multi-threading in CPU-bound tasks.

12. What is the difference between @staticmethod and @classmethod?

  • @staticmethod: Does not take self or cls as an argument.
  • @classmethod: Takes cls as its first argument, representing the class itself.

13. What is Python’s __init__ method?

The __init__ method initializes a class’s attributes and is called when a class is instantiated.
Example:

class Person:
    def __init__(self, name):
        self.name = name

14. How do you manage exceptions in Python?

Use try, except, else, and finally blocks for exception handling.
Example:

try:
    x = 10 / 0
except ZeroDivisionError:
    print("Cannot divide by zero!")
finally:
    print("Execution finished.")

15. What are metaclasses in Python?

Metaclasses are classes that define the behavior and structure of other classes. They control class creation.

Python Coding Challenges

  1. Reverse a string without using slicing.
  2. Find the second largest number in a list.
  3. Write a function to check if a string has balanced parentheses.
  4. Implement a stack using Python lists.
  5. Count the frequency of characters in a string.

Tips for Python Interviews

  1. Understand the Basics: Focus on syntax, core concepts, and libraries.
  2. Practice Regularly: Use platforms like LeetCode, HackerRank, and Codewars.
  3. Communicate Clearly: Explain your approach while solving problems.
  4. Prepare for Applications: Study relevant Python frameworks or libraries like Django, Flask, or NumPy.
  5. Stay Updated: Python evolves with new features and enhancements.

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