Python Interview Questions and Answers [2023]

Beginner Python Interview Questions and Answers

What is Python?

Python is a high-level, interpreted programming language that is easy to learn and use. It was first released in 1991 by Guido van Rossum.

What is the difference between Python 2 and Python 3?

Python 2 and Python 3 are two different versions of the Python programming language. Python 2 is no longer supported, while Python 3 is the current version. Python 3 has some differences in syntax and features from Python 2.

What are variables in Python?

Variables are used to store data in Python. They can hold different types of data, such as numbers, strings, and lists.

For example, to create a variable called “x” and assign it the value 10.

x = 10

What are the data types in Python?

Python has several built-in data types, including integers, floats, strings, lists, tuples, sets, and dictionaries.

Numeric Types
Sequence Types
Text Type
Mapping Types
Set Types
Boolean Type
Binary Types

What is a function in Python?

A function is a block of code that performs a specific task. It can take inputs and return outputs, and can be reused throughout a program.

How do you define a function in Python?

In Python, you define a function using the def keyword, followed by the function name, inputs (if any), and a colon. The function body is indented below.

Syntax :

def function_name(arguments):
    #Code Block
    return output

What is a module in Python?

A module is a file containing Python code that can be imported and used in other Python programs. Python has many built-in modules, as well as thousands of third-party modules available for download.

How do you import a module in Python?

In Python, you can import a module using the import keyword, followed by the module name. You can then use the functions and variables defined in the module.

# Import a module
import math
# Import a module and rename it
import numpy as np
# Import specific functions from a module
from datetime import date, time
# Import all functions from a module (not recommended)
from random import *

What is an if-else statement in Python?

An if statement is used to perform a certain action based on a condition. If the condition is true, the code inside the if statement is executed, otherwise it is skipped.

Syntax :

if condition:
    #code block to execute if condition is true
else:
    #code block to execute if condition is false

What is a loop in Python?

A loop is used to repeat a certain block of code multiple times. Python has two main types of loops: for loops, which iterate over a sequence of items, and while loops, which repeat while a certain condition is true.

Syntax :

for element in sequence:
    # code block to execute for each element

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

A list and a tuple are both types of sequences in Python, but a list is mutable (can be changed), while a tuple is immutable (cannot be changed).

Example :

# creating a list
my_list = [1, 2, 3, 4]
# creating a tuple
my_tuple = (1, 2, 3, 4)

What is a dictionary in Python?

A dictionary is a collection of key-value pairs in Python. It is unordered and can be modified.

Syntax :

my_dict = {"key1": "value1", "key2": "value2", "key3": "value3"}

What is the difference between a set and a list in Python?

A set is an unordered collection of unique elements, while a list is an ordered collection of elements that can have duplicates.

Example :

# creating a list
my_list = [1, 2, 3, 3, 4, 4, 5]
# creating a set
my_set = {1, 2, 3, 4, 5}

What is the difference between an object and a class in Python?

A class is a blueprint for creating objects in Python, while an object is an instance of a class.

What is inheritance in Python?

Inheritance is a way for a class to inherit properties and methods from a parent class. It allows for code reuse and can simplify code structure.

What is polymorphism in Python?

Polymorphism is the ability of an object to take on many forms. In Python, this is often achieved through method overloading and overriding.

What is a lambda function in Python?

A lambda function is a small, anonymous function in Python. It can take any number of arguments, but can only have one expression.

What is a module in Python?

A module is a file containing Python code that can be imported and used in other Python programs. Python has many built-in modules, as well as thousands of third-party modules available for download.

What is a package in Python?

A package is a collection of modules in Python. It allows for better organization of code and can simplify program structure.

What is pip in Python?

Pip is a package manager for Python that allows you to easily install and manage third-party packages. It is included with most Python installations.

Intermediate Python Interview Questions and Answers

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

A shallow copy creates a new object, but the contents of the original object are still referenced. A deep copy creates a new object and recursively copies all of its contents, so the new object is completely independent.

What is a decorator in Python?

A decorator is a function that modifies the behavior of another function. It is often used to add functionality or to modify the input or output of a function.

Syntax :

@decorator_function
def my_function():
    # function body

What is a generator in Python?

A generator is a type of iterator that generates values on-the-fly. It can be more memory-efficient than creating a list or other sequence.

Example :

def even_numbers(n):
    i = 0
    while i < n:
        yield 2*ii += 1

What is a context manager in Python?

A context manager is used to manage resources, such as opening and closing files or network connections, by automatically handling the setup and cleanup tasks.

What is a metaclass in Python?

A metaclass is a class that defines the behavior of other classes. It can be used to customize class creation and add additional functionality.

Example :

class MyMeta(type):
    def __new__(cls, name, bases, attrs):
        attrs['my_method'] = lambda self: print('Hello, Goom!')
        return super().__new__(cls, name, bases, attrs)

What is the difference between a module and a package in Python?

A module is a single file containing Python code, while a package is a directory containing one or more modules, along with an __init__.py file.

What is the Global Interpreter Lock (GIL) in Python?

The GIL is a mechanism used by Python to ensure that only one thread can execute Python bytecode at a time. This can limit the performance of multi-threaded programs.

What is the difference between a thread and a process in Python?

A thread is a unit of execution within a process, while a process is a separate instance of a program that runs independently.

What is the difference between __str__ and __repr__ in Python?

__str__ is called when a string representation of an object is needed, while __repr__ is called when a more complete representation of the object is needed, such as for debugging.

What is the difference between is and == in Python?

‘is’ is used to check if two objects are the same object in memory, while == is used to check if two objects have the same value.

What is the difference between asyncio and threads in Python?

asyncio is a Python module for asynchronous programming that uses coroutines, while threads are used for concurrent programming. asyncio can be more efficient than threads for certain types of I/O-bound tasks.

What is the difference between a list comprehension and a generator expression in Python?

A list comprehension creates a list, while a generator expression creates a generator object. Generator expressions are more memory-efficient for large sequences.

What is a Python package manager?

A Python package manager is a tool used to install, manage, and update Python packages. Examples include pip and conda.

What is the difference between a function and a method in Python?

A function is a standalone block of code that can take input arguments and return a value, while a method is a function that is bound to an object.

What is the difference between range and xrange in Python?

range is a built-in function that returns a sequence of integers, while xrange is a generator that returns the integers one at a time. xrange was only used in Python 2.x and is not available in Python 3.x.

What is the difference between append and extend in Python?

append adds a single element to the end of a list, while extend adds the elements of another list to the end of a list.

What is a Python iterator?

A Python iterator is an object that generates values on-the-fly using the __next__ method. It is used to efficiently iterate over large sequences.

What is a Python closure?

A Python closure is a function that has access to variables from its enclosing lexical scope, even after the enclosing function has completed execution.

What is the difference between a static method and a class method in Python?

A static method is a method that does not require access to an instance of a class, while a class method is a method that requires access to the class itself.

Advanced Python Interview Questions and Answers

What is the difference between a Python function and a Python coroutine?

A coroutine is a function that can suspend and resume its execution, allowing other coroutines to run in the meantime. It is used for asynchronous programming and can be more efficient than using threads.

What is the Python Global Interpreter Lock (GIL) and how does it impact Python performance?

The GIL is a mechanism used by Python to ensure that only one thread can execute Python bytecode at a time. This can limit the performance of multi-threaded programs, but it can also simplify the implementation of the Python interpreter.

What are some strategies for improving the performance of Python code?

Strategies for improving Python performance include using built-in functions, minimizing the use of global variables, using list comprehensions instead of loops, and using libraries that are written in C or Cython.

What is the difference between a Python module and a Python package, and how are they organized?

A Python module is a single file containing Python code, while a Python package is a directory containing one or more modules, along with an __init__.py file. Packages can be organized using sub-packages and nested packages.

What is the difference between a Python module and a Python namespace?

A Python namespace is a collection of symbols, such as variables, functions, and classes, that are defined within a particular context, such as a module or a class.

What is the difference between a Python list and a Python generator, and when would you use each one?

A Python list is a sequence of values that is stored in memory, while a Python generator is an iterator that generates values on-the-fly. Generators are often more memory-efficient for large sequences.

What is the difference between a Python decorator and a Python context manager?

A Python decorator is a function that modifies the behavior of another function, while a Python context manager is used to manage resources, such as opening and closing files or network connections, by automatically handling the setup and cleanup tasks.

What is a Python metaclass, and how can it be used to customize class creation?

A Python metaclass is a class that defines the behavior of other classes. It can be used to customize class creation and add additional functionality, such as automatically registering classes with a registry or enforcing certain class attributes.

What is the difference between a Python class and a Python instance, and how are they related?

A Python class is a blueprint for creating objects, while a Python instance is an object created from a class. Instances can have their own attributes and methods, but they also inherit attributes and methods from their class.

What is the difference between a Python abstract base class and a Python interface, and how can they be used to enforce a class hierarchy?

A Python abstract base class is a class that cannot be instantiated directly, but must be subclassed. It is used to define a common interface for a set of related classes. A Python interface is a set of methods that a class must implement to be considered a member of a particular interface. They can be used to enforce a class hierarchy and ensure that all classes that implement a particular interface have a common set of methods.

What is the purpose of the Python yield keyword, and how is it used in a generator function?

The yield keyword is used in a generator function to suspend execution and return a value to the caller. The function can then be resumed from where it left off, allowing it to generate a sequence of values on-the-fly.

def my_generator():
    yield 1
    yield 2
    yield 3

What is the difference between a Python closure and a Python decorator, and how are they related?

A Python closure is a function that remembers the values of its enclosing variables, even after they have gone out of scope. A Python decorator is a function that modifies the behavior of another function. Decorators often use closures to store additional state or metadata about the decorated function.

What is the difference between a Python thread and a Python process, and when would you use each one?

A Python thread is a lightweight process that runs within a single Python interpreter, while a Python process is a separate instance of the Python interpreter. Threads are often used for I/O-bound tasks, while processes are used for CPU-bound tasks or for parallelizing work across multiple CPUs.

What is the Python Global Interpreter Lock (GIL), and how does it impact the performance of multi-threaded Python programs?

The GIL is a mechanism used by Python to ensure that only one thread can execute Python bytecode at a time. This can limit the performance of multi-threaded programs, as only one thread can be executing Python code at a time. However, it can also simplify the implementation of the Python interpreter.

What is the difference between a Python set and a Python frozenset, and when would you use each one?

A Python set is an unordered collection of unique values, while a Python frozenset is an immutable version of a set. Sets are often used for filtering or deduplicating values, while frozensets are used when a hashable, immutable set is needed.

What is the difference between a Python iterator and a Python iterable, and how are they used in a for loop?

A Python iterable is an object that can be iterated over, such as a list, tuple, or dictionary. An iterator is an object that generates the next value in the sequence when the next() method is called. The for loop in Python uses iterators to iterate over iterables.

my_list = [1, 2, 3]
# my_list is an iterable
for item in my_list:
    print(item)

What is the purpose of the Python asyncio library, and how does it support asynchronous programming in Python?

The asyncio library is a framework for writing asynchronous code in Python. It provides support for coroutines, event loops, and asynchronous I/O. Asynchronous programming can be more efficient than traditional synchronous programming, as it allows for non-blocking I/O and can handle many concurrent connections with a small number of threads.

What is the difference between a Python list and a Python tuple, and when would you use each one?

A Python list is a mutable sequence of values, while a Python tuple is an immutable sequence of values. Tuples are often used for returning multiple values from a function or for creating lightweight data structures, while lists are used for storing and modifying sequences of values.

What is the difference between a Python lambda function and a Python named function, and when would you use each one?

A Python lambda function is an anonymous function that can be defined inline and passed as an argument to another function. A named function is a function that is defined with a name and can be called from other parts of the code. Lambda functions are often used for simple, one-line functions.

What is the purpose of the Python with statement, and how is it used to manage resources?

The with statement is used to create a context in which a resource is managed, such as a file or a database connection. It ensures that the resource is properly opened and closed, even if an error occurs during the execution of the code. The with statement can be used with any object that has __enter__() and __exit__() methods defined, allowing for custom resource management.