Are you preparing for a job interview or an exam that involves knowledge about Python? Or maybe you want to quickly refresh your knowledge of common Python topics? In this blog post, we’ve compiled a list of 50 Python interview questions and provided concise answers to help you prepare and ace your Python-related interviews. These questions cover a wide range of Python concepts and will serve as a valuable resource for both beginners and experienced developers.

1. Name Differences Between a List and a Tuple


  • Mutable
  • Higher memory consumption
  • Offers numerous built-in methods
  • Slower iteration
  • Better for operations like insertion and deletion


  • Immutable
  • Lower memory consumption
  • Provides fewer built-in methods
  • Faster iteration
  • Better for accessing elements

2. What Does the Range() Function Do?

The built-in range() function creates a range of integers, making it useful for creating sequences of numbers.

3. How Does the Map() Function Work?

map() is used to transform an iterable into another iterable by applying a specified function to each element. It returns a map object, which can be converted back to a list, for example.

4. What is the Difference between “is” and “==”?

The == operator compares the equality of two values, while the is operator checks if two variables point to the same memory address.

5. What is a Decorator?

Decorators in Python allow you to extend the functionality of functions or classes. They are commonly used for tasks like input validation and error handling.

6. How Does Reduce() Function Work?

The reduce() function applies a function cumulatively to the items of an iterable, reducing it to a single value.

7. How Does the Filter() Function Work?

filter() is used to filter elements from an iterable based on a specified condition, returning an iterator with the filtered values.

8. What is the Difference Between Shallow Copy and a Deep Copy?

In Python, a shallow copy references the children of the original object, while a deep copy creates an independent copy of the original object.

9. What Does Any() Function Do?

The any() function returns True if any element in an iterable is True, otherwise, it returns False.

10. What Does All() Function Do?

The all() function checks if all elements in an iterable are True.

11. What is the Difference Between a Method and a Function?

Methods are associated with objects or classes, while functions are independent of any class or object.

12. What Is the Output of the Following? Why?

nums = [1, 2, 3]
copied_nums = nums
copied_nums[0] = 1000

Output: [1000, 2, 3]

Explanation: In Python, the = operator does not create a copy of an object; it creates a new variable that refers to the original object.

13. How Do You Reverse a List in Python?

You can reverse a list using the built-in reverse() method of a list.

14. What Does ‘self’ Mean in a Class?

In a class, self refers to the class instance itself and is used to access properties that belong to the class.

15. How to Concatenate a List in Python?

To concatenate two or more lists in Python, use the assignment operator (+).

16. What are Pickling and Unpickling Conceptually?

Pickling is the process of converting Python objects into a byte stream, while unpickling is the opposite.

17. Are Dictionaries Faster to Lookup than Lists?

Yes, dictionaries have faster lookup times (O(1)) compared to lists (O(n)).

18. What is a Module in Python?

A module in Python is a file that contains functions and global variables and can be imported for use in other programs.

19. What is a Package in Python?

A package is a directory containing multiple Python modules.

20. What is Considered a Library in Python?

A library in Python is a publicly available package or module that provides additional functionality.

21. Why Converting a List to a Set Removes Duplicates?

Converting a list to a set removes duplicates because a set is a collection of unique values.

22. Can You Swap Two Variables Without a Third?

Yes, you can swap two variables without using a third variable by utilizing tuple unpacking.

a = 1
b = 2
a, b = b, a

23. What Are Comprehensions in Python?

Comprehensions are shorthands for writing for loops in Python. They come in four types: list comprehensions, dictionary comprehensions, set comprehensions, and generator comprehensions.

24. Why and When Use List Comprehensions?

List comprehensions are used to make code more concise and readable, especially when filtering or transforming data.

25. What Does the Enumerate() Function Do?

The enumerate() function pairs elements of an iterable with their index, making it useful when looping through a list and tracking index positions.

26. What Is the Itertools Module?

The itertools module is a powerful Python module that provides useful functions for working with iterators and iterables. It offers a variety of tools for creating and working with iterators, such as generating permutations, combinations, and infinite sequences. One common use is to find all permutations of a list of values:

from itertools import permutations

a = [1, 2, 3]
perms = permutations(a)

27. What is the Difference between Pass, Continue, and Break Statements?

  • pass is used when you need a placeholder and want to do nothing. It’s often used to create empty classes or functions.
  • continue is used within loops to skip the current iteration and move to the next one.
  • break is used to exit a loop prematurely, stopping the loop’s execution.

28. What is the Ternary Operator?

The ternary operator, also known as the conditional operator, allows you to write one-liner if-else statements in Python. It has the following syntax:

pythonCopy code

value_if_true if condition else value_if_false

It’s a concise way to make decisions based on a condition, for example:

is_ready = False
result = "Yay" if is_ready else "Nope"

29. How Could You Simplify This?

Simplify the condition check using a list:

pythonCopy code

if n == 0 or n == 1 or n == 2 or n == 3 or n == 4 or n == 5:


pythonCopy code

if n in [0, 1, 2, 3, 4, 5]:

30. Explain the Difference between Pop(), Remove(), and Del?

  • pop(): Removes an element from a list at a specific index and returns the removed value.
  • remove(): Removes the first occurrence of a specified value from a list.
  • del: Deletes an element from a list at a specific index or deletes the entire list.

31. What is an Enumeration? How Do You Create One?

An enumeration, represented by Enum in Python, is a collection of symbolic names associated with unique, constant values. To create an enumeration, you can define a class that inherits from Enum and defines members with unique values.

from enum import Enum

class Color(Enum):
    RED = 1
    GREEN = 2
    BLUE = 3

32. How Do You Check If a Key Exists in a Dictionary?

You can use the in statement to check if a key exists in a dictionary:

data = {"Ronaldo": 7, "Bale": 9, "Messi": 10}
print("Ronaldo" in data)  # True

33. What is a Docstring?

A docstring is a string literal that appears as the first statement in a module, function, class, or method. It serves as documentation for your Python code and can be accessed using the help() function.

def sum(num1, num2):
    '''This is a method that sums up two numbers'''
    return num1 + num2


34. What Are Lambda Expressions?

Lambda expressions, also known as anonymous functions, are concise functions that can have any number of arguments but can only have one expression. They are typically used for small, simple operations.

mult3 = lambda x: x * 3
print(mult3(15.0))  # 45.0

35. What Are F-Strings in Python?

Formatted strings, or F-strings, are a way to format strings by embedding expressions inside them using curly braces {}. They make string formatting more concise and readable.

name = "Nick"
print(f"My name is {name}")

36. What is the Difference Between Dictionary and JSON?

A dictionary is a built-in data structure in Python, while JSON (JavaScript Object Notation) is a text-based data interchange format. JSON can be converted to a Python dictionary and vice versa.

37. Python Lists vs. Numpy Arrays

Python lists are versatile but less efficient for numerical operations. NumPy arrays are more efficient for numerical computations, provide better memory utilization, and support vectorized operations.

38. What is Pep8?

PEP 8, or Python Enhancement Proposal 8, is a style guide for writing Python code. It provides guidelines on how to format code for readability and consistency.

39. What is the __init__() Method?

__init__() is a constructor method in Python classes. It is automatically called when a new instance of a class is created and is used to initialize attributes or properties of the object.

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

person = Person('Nick')
print(  # Nick

40. What Are Global Variables and Local Variables?

Global variables are defined outside of any function and can be accessed anywhere in the code. Local variables are defined inside a function and can only be accessed within that function.

41. How Do You Handle Exceptions in Python?

Exception handling in Python is essential for dealing with runtime errors gracefully. It involves using the try, except, and optionally finally blocks. Here’s the structure:

    # Code that might raise an exception
except ExceptionType:
    # Code to handle the exception
    # Optional code that always runs, whether an exception occurred or not


    result = 1 + "one"
    print("Exception encountered! Default value will be used")
    result = 10
    print('This always runs')

42. How Do You Check If a Value Exists in a List?

You can use the in statement to check if a value exists in a list:

'A' in ['A', 'B', 'C']  # True
'A' in [1, 2, 3]        # False

43. Can a Tuple Be a Dictionary Key?

Yes, a tuple can be used as a key in a dictionary. This is because tuples are hashable, meaning they have a fixed value that does not change during their lifetime, making them suitable for dictionary keys.

44. What is the Join() Method? How Does It Work?

The join() method is a built-in string method in Python used to concatenate elements of an iterable (usually a list) into a single string. It works by taking a separator string and joining the elements with that separator.


chars = ["H", "e", "l", "l", "o"]
word = "".join(chars)
print(word)  # Hello

45. What is an Iterable?

An iterable is an object in Python that can be looped over, meaning it can return its elements one at a time. Common examples of iterables include lists, dictionaries, and tuples.

46. What is an Iterator?

An iterator is an object that is used to iterate over an iterable. It implements the iterator protocol by having __iter__() and __next__() methods. It allows you to loop through the elements of an iterable one at a time.


fruits = ("apple", "banana", "orange")
fruit_iterator = iter(fruits)

47. What Is a Set?

A set is a built-in data type in Python that represents an unordered collection of unique elements. Sets are defined using curly braces {} or the set() constructor. They are useful for operations that require distinct values.


num_set = {1, 2, 3, 4, 5}
print(num_set)  # {1, 2, 3, 4, 5}

48. How Do You Sort a List in a Reversed Order?

To sort a list in reverse order, you can use the sort() method with the reverse=True parameter:

fruits = ["Banana", "Apple", "Cranberry"]
print(fruits)  # ['Cranberry', 'Banana', 'Apple']

49. How Can You Randomize a Python List?

You can randomize the order of elements in a Python list using the shuffle() function from the random module:

import random

x = [1, 2, 3, 4, 5]
print(x)  # Example output: [2, 4, 5, 1, 3]

50. What Does Negative Indexing Mean?

Negative indexing allows you to access elements in a sequence (like a list or string) from the end. The last element is accessed using -1, the second-to-last using -2, and so on.


nums = [1, 2, 3, 4, 5]
print(nums[-2])  # 4

These questions complete our list of the top 50 Python interview questions and answers for 2023. We’ve covered a wide range of Python topics, from fundamental concepts to more advanced programming techniques.

We hope this comprehensive guide helps you prepare for your next Python interview or serves as a valuable reference as you continue your Python journey. If you have any questions or need further clarification on any topic, feel free to ask.


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