Python is one of the most popular programming languages globally. It is an open-source language with simple syntax. Due to its rich ecosystem of libraries like Pandas, NumPy, and Scikit-learn, it is widely used in data science. So, if you are learning Python or aiming to become Python developer, you are moving towards a bright career. To smoothen your journey, we have compiled important Python interview questions. Read the blog to enhance your knowledge.
Basic Python Interview Questions
Q1. What is Python?
Python is a high-level, interpreted programming language known for its simplicity and readability. It supports multiple paradigms, including object-oriented, procedural, and functional programming.
Key Features:
- Open-source and free to use
- Cross-platform compatibility
- Extensive standard library
Q2. What is Pep 8?
PEP 8 stands for Python Enhancement Proposal 8, which defines the coding style guidelines for writing clean, readable Python code. It includes rules about indentation, whitespace, naming conventions, and best practices.
Q3. Is Python an interpreted or compiled language?
Python is an interpreted language. It means that the code is executed line by line at runtime rather than being compiled into machine code before execution.
Q4. What are Dictionary and List Comprehensions in Python?
List and Dictionary comprehensions provide a concise way to create lists and dictionaries in Python.
# List comprehension example
squares = [x**2 for x in range(5)]
print(squares) # Output: [0, 1, 4, 9, 16]
# Dictionary comprehension example
squared_dict = {x: x**2 for x in range(5)}
print(squared_dict) # Output: {0: 0, 1: 1, 2: 4, 3: 9, 4: 16}
Q5. What is a namespace in Python?
A namespace in Python is a system that assigns unique names to variables, functions, and objects to avoid naming conflicts.
Q6. What is a Lambda function?
A Lambda function is an anonymous function (a function without a name) defined using the lambda keyword.
Example: add = lambda a, b: a + b
print(add(5, 3)) # Output: 8
Q7. Explain pickling and unpickling.
Pickling and unpickling are processes used for serializing and deserializing Python objects.
- Pickling: It means converting a Python object into a byte stream.
- Unpickling: It means converting the byte stream back into a Python object.
Advanced Python Interview Questions
Q8. What are Generators in Python?
Generators are functions that return an iterable set of values using yield instead of return. They are memory-efficient.
Q9. What is Flask, and what are its benefits?
Flask is a lightweight web framework for Python used to develop web applications. It is built on Werkzeug and Jinja2.
Benefits:
- Minimalistic and fast
- Flexible and easy to learn
- Built-in development server and debugger
Q10. What is the difference between a tuple and a list?
Feature | List | Tuple |
Mutability | Mutable (can be changed) | Immutable (cannot be changed) |
Performance | Slower | Faster |
Syntax | list = [1,2,3] | tuple = (1,2,3) |
Q11. What is the Dogpile effect? How can it be prevented?
The Dogpile effect occurs when a cache expires, and multiple requests hit the database simultaneously. It can be prevented by using a semaphore lock to allow only one request to regenerate the cache.
Q12. What is the map() function in Python?
The map() function applies a function to all items in an iterable.
Example: def square(num):
return num ** 2
numbers = [1, 2, 3, 4]
result = list(map(square, numbers))
print(result) # Output: [1, 4, 9, 16]
Q13. What are Python packages?
Python packages are namespaces that contain multiple modules.
Example: package_name/
|– __init__.py
|– module1.py
|– module2.py
Q14. How do you debug a Python program?
You can debug a Python script using: $ python -m pdb script.py
This starts with Python’s built-in debugger (pdb).
Q15. How can you copy an object in Python?
In Python, you can copy an object using the copy module. There are two common methods:
- Deep Copy (copy.deepcopy(obj))
This creates a completely independent copy of the object, including all nested objects.
However, not all objects can be copied, especially those that involve system resources like file handles, sockets, or threads.
Q16. How can you convert a number to a string?
To convert a number into a string, use the built-in str() function. If you need an octal or hexadecimal representation, use the built-in oct() or hex() functions.
Example:
num = 25
str_num = str(num) # Converts number to string
print(str_num) # Output: ’25’
# Octal and Hexadecimal representation
print(oct(25)) # Output: ‘0o31’
print(hex(25)) # Output: ‘0x19’
Q17. What is a module and a package in Python?
- A module is a single Python file containing variables, functions, and classes that can be imported and used in other Python programs.
- A package is a collection of modules organized in directories. It contains an __init__.py file that indicates it’s a package.
Q18. How to delete a file in Python?
You can delete a file using the os.remove() or os.unlink() function from the os module.
Example:
import os
file_path = “test.txt”
# Check if file exists before deleting
if os.path.exists(file_path):
os.remove(file_path)
print(“File deleted successfully”)
else:
print(“File not found”)
Q19. Explain slicing.
Slicing is a technique used to extract a portion of a sequence (like a list, tuple, or string) using a specific range of indices.
Syntax:
sequence[start:stop:step]
- start: The index where slicing begins (default is 0).
- stop: The index where slicing ends (not included).
- step: The interval between elements (default is 1).
Example:
my_list = [10, 20, 30, 40, 50, 60]
print(my_list[1:4]) # Output: [20, 30, 40]
print(my_list[:3]) # Output: [10, 20, 30] (From start)
print(my_list[::2]) # Output: [10, 30, 50] (Every second element)
print(my_list[::-1]) # Output: [60, 50, 40, 30, 20, 10] (Reverse)
Q20. What are the tools that help to discover bugs or perform the static analysis?
Python provides several tools for bug detection and static code analysis:
- PyChecker: A static analysis tool that detects bugs, code complexity, and style issues in Python source code.
- Pylint: A widely used tool that checks code quality, enforces coding standards (PEP 8), and identifies potential errors in Python modules.
Example:
pylint my_script.py # Run Pylint on a Python file
These tools help ensure clean, efficient, and error-free Python code.
So, above are the mentioned interview questions & answers for Python jobs, candidates should go through it and practice more coding questions to clear their job interview efficiently.
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