20 Best Python Interview Questions and Answers

Python is a powerful and flexible programming language. It is used in many domains, from Web Development to Data Science. It serves as a general purpose programming language for large projects, and has the capacity to combine both simplicity and sophistication in the same program.

Python is an object-oriented programming language that lets you work quickly and integrate systems more effectively. Python has been around for a long time, but it remains one of the most popular languages in use today due to its simplicity; it’s easy to learn how to code with Python if you’re just starting out.

In this blog, you’ll learn the important and frequently asked interview questions that help you clear the interview process. We have curated the most useful and tricky questions and answers to get an overall knowledge of python programming concepts.

1. Explain about metaclasses in Python

Ans. A metaclass in python programming can be a class within a class that defines the behavior of a class. To understand how the metaclass works, you need to have a fundamental knowledge of python classes. Most of the programming language classes are just some piece of code that describes how the object is produced. It is a similar kind of case in python too. But, in python classes can produce objects too.

Metaclasses can be represented as shown below

Eg:  MyClass = MetaClass()

       my_object = MyClass()

Using type to create the below:

MyClass = type(‘My Class’, (), {})

The type lets you create a metaclass. The type is a metaclass that python needs to create all the classes in the background.

2. Explain Python ternary conditional operator?

Ans. Ternary operators are also called Conditional expressions that evaluate any code depending on the condition either true or false. This option was included in the python 2.5 version, below is an example to see how a conditional operator works.

# Example of a conditional operator

c,d  = 100, 200

# Copy value of a in min if c < d else copy d

min = c if c < d else d


Output: 100

3. Define PEP-8?

Ans. The full form of PEP is the Python Enhancement Proposal, it is basically a document that explains new features introduced in python and python document aspects like style, design for the community. 

PEP8 is a simple documented format that provides information on rules and best practices for writing a python code. Its primary goal is to enhance readability and consistency.

4. Describe Python Memory Management.

Ans. Python Memory Management is carried out by the memory manager present in Python itself. The memory manager is responsible for handling an efficient and maintainable code. The key factor of memory management for every software developer is the allocation of heap space memory.

5. Define Python Namespace.

Ans. Namespaces are a collection of symbolic names having information about the objects with reference to each name. The namespace can be considered as a dictionary that contains keys that are referred to as object names and the values are the objects themselves. Namespaces are used as a system for naming which makes sure all the names are unique to avoid conflicts while naming.

6. Explain Local and Global Variables in Python.

Ans. Local variables are inside a function and the global variables are declared outside a function or in a global space.

7. Differentiate Python Arrays from lists.

Ans. An array in python is a container that holds a fixed number of items and lists are used to store multiple items in a single variable. 

8. How to reverse an integer in Python?

Ans: In Python, an integer can be revered in the two following ways:

  1. Reverse an integer using the loop
  2. Reverse an integer using recursive function

Read the article with an example here: Reverse an Integer in Python 

9. How to find a length of a list in Python?

Ans. In Python, a list is declared using a set of square brackets where a comma separates each element. The list in Python is declared as follows: Find Python List Length here.

10. What is an indentation in Python?

Ans. The Indentation error occurs in the Python script due to the whitespace of tab errors. The code in Python script is arranged based on whitespaces. Read more about Python Indentation.

11. Explain Python Lambda Function.

Ans. An anonymous function is usually known as Lamba, it can contain any number of arguments but should include only one expression.

12. Describe Self in Python.

Ans. A Self in Python is used to represent an instance of the class. It can be used to access the attributes and methods of a python class. 

13. What are Iterators and Generators in Python?

Ans. Iterators can be defined as containers for objects, they can be looped over the objects. Python Generators are used to simplify the process of creating iterators, It can be performed by defining a function using the yield keyword instead of using the return statement.

14. What is pickling in Python?

Ans. Pickling is used to convert a python object hierarchy to a byte stream. It is mainly used to serialize and deserialize a Python object structure. 

15. How to capitalize the initial letter of a string in Python?

Ans. The capitalize() method is used to capitalize the initial letter of a string.

16. What does “yield” mean in python?

Ans. Yield is a keyword used in Python to return a function without breaking the state of the local variable, and execution begins when the function is called. Any function that contains a yield keyword is called a generator.

17. How to check if a file exists in python?

Ans. The Python exists () function is used to check the existence of a specific file or directory. It is also used to determine if a URL refers to an open file description. It returns the true, for the Boolean value of the file and returns otherwise if false. It is used by os module and sub.mod os.path as os.path.exists (path).

18. What is the difference between the Class method and the Static method?


Class Method:

The class method consists of an inbuilt decorator called the “@classmethod decorator”, which is an expression that is evaluated after the function is defined. The output of the evaluation overshadows the definition of the function. A class method accepts the class as an implicit first argument similar to how an instance method accepts an instance.

Static Method:

A static method does not accept an implicit first argument. It is also a method that is tied to the class and not to the object of the class. A static method cannot access or change the state of the class. It is present in the class because it makes sense that the method is present in the class.

19. How to list files in a directory?

Ans. In python, listing files in a directory requires os.listdir() which helps you in getting all the files and directories. Also, use os.walk() in case of listing the root directory, subdirectory, and current directory file names in a directory tree.

20. How to sort a dictionary by value?

Ans. The “for loop” is used to sort a dictionary. The sorted() function arranges the values of a dictionary, the sorted values are then looped to find the keys of each value. These key-value pairs are then added to a new dictionary.

Related articles:

  1. Python MatplotLib Tutorial – A guide to plotting library for python.
  2. PyOpenGL Tutorial – A complete guide on creating graphics in Python.

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