Interview questions for Python

If you have Python as a language in your CV and you don’t know what to study, here are some entry-level question and answers for Python Language.

1. What is Python? How is it different from other programming languages?

Python is an interpreted high-level programming language that is used for various applications such as web development, scientific computing, data analysis, artificial intelligence, and machine learning. It is different from other programming languages because of its simplicity and ease of use. It has a concise syntax that allows programmers to express complex ideas in a few lines of code.

2. What are the different data types in Python?

Python has several built-in data types including integers, floating-point numbers, complex numbers, strings, lists, tuples, dictionaries, and sets.

1. Numeric types: These include integers, floating-point numbers, and complex numbers. Integers represent whole numbers, while floating-point numbers represent decimal numbers. Complex numbers are numbers with a real and imaginary part.
2. String: A string is a sequence of characters. Strings are used to represent text in Python. They can be defined using single quotes, double quotes, or triple quotes.
3. Boolean: A Boolean is a data type that can have two possible values: True or False. Booleans are often used in conditional statements and logical operations.
4. List: A list is an ordered collection of values. Each value in the list is assigned an index, starting from 0. Lists can contain values of different data types, and they can be modified after they are created.
5. Tuple: A tuple is similar to a list, but it is immutable, which means that it cannot be modified after it is created. Tuples are often used to represent fixed sequences of data.
6. Set: A set is an unordered collection of unique values. Sets are used to perform operations such as union, intersection, and difference on collections of data.
7. Dictionary: A dictionary is a collection of key-value pairs. Each key in the dictionary is associated with a value, and the keys are used to access the values in the dictionary.
8. None: None is a special data type that represents the absence of a value. It is often used to represent null or undefined values.

3. Explain the concept of list comprehension in Python.

List comprehension is a concise way to create a new list in Python. It allows you to create a new list by iterating over an existing list and applying a function to each element of the list. The resulting list can be filtered and modified as per the requirement.

4. What is PEP 8 and why is it important?

PEP 8 is a set of guidelines for writing Python code that is readable and consistent. It is important because it makes the code more maintainable and helps in identifying and fixing errors quickly.

5. What is the difference between a tuple and a list in Python?

A tuple is an immutable collection of elements, while a list is a mutable collection of elements. Tuples are generally used to represent a fixed set of elements, while lists are used for dynamic sets of elements that may be added, removed, or modified.

6. How do you handle errors and exceptions in Python?

In Python, errors and exceptions can be handled using try-except blocks. The try block contains the code that may raise an exception, while the except block contains the code to handle the exception.

7. Explain the difference between “is” and “==” in Python.

The “is” operator checks if two variables refer to the same object, while the “==” operator checks if two variables have the same value.

8. What is the purpose of “self” in Python?

“self” is a reference to the current instance of a class in Python. It is used to access the instance variables and methods of the class.

9. What is a lambda function and how is it used in Python?

A lambda function is an anonymous function that can be defined in a single line of code. It is used when a function is required for a short period of time and doesn’t need a name. It can take any number of arguments, but can only have one expression.

10. How does Python implement inheritance?

Python implements inheritance by allowing a subclass to inherit the attributes and methods of its parent class. Inheritance is achieved by using the “super” keyword in the subclass.

11. Explain the concept of decorators in Python.

A decorator is a function that takes another function as input and returns a modified version of that function. Decorators are used to modify or enhance the behavior of functions without changing their source code. They are used to add functionality to an existing function.

12. What are the different ways to install packages in Python?

Packages can be installed in Python using pip, conda, or by manually installing the package.

13. How do you perform file I/O operations in Python?

File I/O operations can be performed in Python using the built-in “open()” function. It is used to open a file and read or write data to it.

14. What are some built-in modules in Python?

Some of the built-in modules in Python include math, datetime, os, sys, random etc. Below are just a few examples of the many built-in modules available in Python. By using these modules, developers can save time and effort by leveraging pre-existing code that has been tested and optimized for a wide range of tasks.

1. os: Provides a way to interface with the operating system and perform operations on files and directories.
2. sys: Provides access to some variables used or maintained by the interpreter and functions that interact with the interpreter.
3. math: Provides access to a variety of mathematical functions and constants.
4. random: Provides functions for generating random numbers and samples from various distributions.
5. datetime: Provides classes for working with dates, times, and time intervals.
6. re: Provides regular expression matching operations.
7. json: Provides functions for working with JSON data.
8. csv: Provides functions for reading and writing CSV files.
9. urllib: Provides a high-level interface for working with URLs and URIs.
10. pickle: Provides functions for serializing and deserializing Python objects.

15. How does multithreading work in Python?

In Python, multithreading is achieved using the “threading” module. It allows multiple threads to run concurrently and share the same resources.

16. Explain the concept of generators in Python.

Generators are a type of function in Python that can be used to create iterators. An iterator is an object that generates a sequence of values, which can be accessed one at a time. Generators are a convenient way to generate a sequence of values without having to store them all in memory at once, which is useful when working with large amounts of data.

17. What is the difference between deep copy and shallow copy in Python?

In Python, a shallow copy creates a new object that points to the same memory location as the original object. Any changes made to the original object will also affect the copy. A deep copy creates a new object with a new memory location that is a complete copy of the original object. Changes made to the original object will not affect the copy.

18. How do you create a virtual environment in Python?

A virtual environment can be created in Python using the “venv” module. The steps to create a virtual environment are:

• Open a terminal or command prompt
• Navigate to the directory where you want to create the virtual environment
• Type “python -m venv env_name” (replace “env_name” with the name you want to give to your environment)
• Activate the virtual environment using the command “source env_name/bin/activate” on Linux/Mac or “env_name\Scripts\activate.bat” on Windows

19. What is Flask and how is it used in Python?

Flask is a micro web framework in Python that is used to develop web applications. It is a lightweight framework that provides basic tools and features for creating web applications such as routing, request handling, and templates. Flask is used to build small to medium-sized web applications that don’t require complex functionality.

20. How does Python handle memory management?

Python uses automatic memory management through a process called garbage collection. When an object is no longer needed, the garbage collector removes it from memory. Python also has a built-in mechanism called reference counting that keeps track of the number of references to an object. When the reference count of an object becomes zero, the object is deleted. Python also has a mechanism for detecting and preventing memory leaks.