40 Most Important Python Interview Questions for Freshers

40 Basic and Most Important Python Interview Questions for Freshers | Python institute Delhi

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Programming in Python is a fundamental requirement for most beginner-level positions in the technological sector since it is one of the most widespread and adaptable programming languages. To help overcome this crucial stage of your professional life, experts from a top python training institute in Delhi have created an extensive set of Python interview questions meant explicitly for beginners.

From basic Python concepts to advanced programming techniques, this article will discuss various questions curated from python course institute.

Below are most important 40 python interview questions that will make you successful.

Basic Python Concepts

Q1: What is Python? What are its key features?

Python is a high-level, interpreted programming language known for its simplicity and readability. Key features include:

  • Easy to learn and read syntax
  • Dynamically typed
  • Object-oriented programming support
  • Extensive standard library
  • Cross-platform compatibility
  • Strong community support

Q2: Can you explain the differences between Python 2 and Python 3? 

Some key differences include:

  • Print statement: In Python 2, it’s a statement; in Python 3, it’s a function.
  • Integer division: Python 3 returns a float by default, while Python 2 returns an integer.
  • Unicode support: Python 3 has better Unicode support.
  • Range function: In Python 3, range() returns a range object instead of a list.

Q3: How is memory managed in Python?

Python uses automatic memory management through garbage collection. The Python Memory Manager handles memory allocation and deallocation. Objects with zero references are automatically garbage collected.

Q4: What are Python modules? How do you import them?

Modules are files containing Python code. These files are often imported and used in other Python programs. you can use the ‘import’ keyword for this module:

import math
from datetime import datetime

Q5: Explain Python’s use of indentation.

Python uses indentation to define code blocks, unlike many other languages that use curly braces. Consistent indentation is crucial for proper code execution. For example:

if x > 0:
    print("Positive")
    x += 1
else:
    print("Non-positive")
    x -= 1

Data Types and Variables

Q6: What are the main data types in Python?

The main data types in Python are:

  • Numeric: int, float, complex
  • Sequence: list, tuple, range
  • Text: str
  • Mapping: dict
  • Set: set, frozenset
  • Boolean: bool

Q7: What is the difference between a list and a tuple?

Lists are mutable (can be modified after creation) and use square brackets []. Tuples are immutable (cannot be modified after creation) and use parentheses ().

my_list = [1, 2, 3]  # Mutable
my_tuple = (1, 2, 3)  # Immutable

Q8: How do you create a dictionary in Python?

Curly braces {} with key-value pairs are used to create dictionaries:

my_dict = {"name": "Jenny", "age": 37, "city": "Delhi

Q9: What is a set in Python? How is it different from a list?

A set is a collection of unique elements which are in no set order. Unlike lists, sets do not allow duplicate values and are not indexed. Sets are created using curly braces {} or the set() function:

my_set = {1, 2, 3, 4, 5}
another_set = set([1, 2, 3, 3, 4, 5])  # Duplicates are automatically removed

Q10: Explain the concept of mutable and immutable objects in Python.

Mutable objects can be modified after creation (e.g., lists, dictionaries, sets), while immutable objects cannot be changed once created (e.g., tuples, strings, integers).

Control Structures and Loops

Q11: What is the difference between ‘break’ and ‘continue’ statements?

Q12: How do you use a ‘for’ loop in Python?

  • Continue’ skips the rest of the current iteration and it will move you to the next iteration.
  • Break’ exits the entire loop.

Example:

for i in range(10):
    if i == 3:
        continue  # Skip 3
    if i == 7:
        break  # Exit loop when i is 7
    print(i)

Q12: How do you use a ‘for’ loop in Python?

‘for’ loops are used to iterate over sequences (lists, tuples, strings, etc.) or other iterable objects:

fruits = ["apple", "banana", "cherry"]
for fruit in fruits:
print(fruit)

Q13: Explain the ‘while’ loop in Python.

A ‘while’ loop continues executing a block of code as long as a condition is true:

count = 0
while count < 5:
    print(count)
    count += 1

Q14: What is the purpose of the ‘else’ clause in loops?

The ‘else’ clause in loops is executed when the loop completes normally (without encountering a ‘break’ statement):

for i in range(5):
    print(i)
else:
    print("Loop completed successfully")

Q15: How do you use conditional statements in Python?

‘if’, ‘elif’, and ‘else’ keywords are used for conditional statements:

x = 10
if x > 0:
    print("Positive")
elif x < 0:
    print("Negative")
else:
    print("Zero")

Functions and Lambda Expressions

Q16: How do you define a function in Python?

Functions are defined using the ‘def’ keyword:

def greet(name):
    return f"Hello, {name}!"

Q17: What are *args and **kwargs in Python?

  • *args let a function accept any number of positional arguments.
  • **kwargs lets a function to accept any number of keyword arguments.
def example_function(*args, **kwargs):
print("Args:", args)
print("Kwargs:", kwargs)
example_function(1, 2, 3, name="John", age=30)

Q18: Explain lambda functions in Python.

Lambda are small, anonymous functions. These are defined through the ‘lambda’ keyword:

square = lambda x: x ** 2
print(square(5))  # Output: 25

Q19: What is the difference between local and global variables?

Local variables are defined within a function. These variables can only be accessed within that function. Global variables are defined outside of functions and can be accessed throughout the entire program.

Q20: How do you return multiple values from a function?

You can return multiple values as a tuple, list, or dictionary:

def get_person_info():
    return "John", 30, "New York"

name, age, city = get_person_info()

Object-Oriented Programming (OOP)

Q21: What are the main principles of Object-Oriented Programming?

The main principles of OOP are:

  • Encapsulation
  • Inheritance
  • Polymorphism
  • Abstraction

Q22: How do you define a class in Python?

Classes are defined using the ‘class’ keyword:

class Person:
def __init__(self, name, age):
self.name = name
self.age = age
def greet(self):
return f"Hello, my name is {self.name}"

Q23: Explain inheritance in Python.

Inheritance lets a class inherit attributes and methods from any other class:

class Student(Person):
    def __init__(self, name, age, student_id):
        super().__init__(name, age)
        self.student_id = student_id

Q24: What is method overriding in Python?

When a method is already defined in its superclass, the method overriding occurs:

class Animal:
    def speak(self):
        return "Animal speaks"

class Dog(Animal):
    def speak(self):
        return "Dog barks"

Q25: How do you implement encapsulation in Python?

Encapsulation is achieved using private attributes (prefixed with double underscores):

class BankAccount:
    def __init__(self, balance):
        self.__balance = balance

    def get_balance(self):
        return self.__balance

File Handling and Exception Handling

Q26: How do you open and close a file in Python?

Files can be opened using the ‘open()’ function and should be closed after use:

file = open("example.txt", "r")
# Perform operations
file.close()

# Alternatively, use a context manager:
with open("example.txt", "r") as file:
    # Perform operations

Q27: What is exception handling in Python?

Exception handling allows you to gracefully handle errors that may occur during program execution:

try:
    result = 10 / 0
except ZeroDivisionError:
    print("Cannot divide by zero")
finally:
    print("This always executes")

Q28: How do you create custom exceptions?

Custom exceptions are subclasses of the Exception class:

class CustomError(Exception):
    pass

raise CustomError("This is a custom error")

Q29: What is the difference between ‘read()’ and ‘readline()’ methods?

  • ‘read()’ reads the entire file content as a single string.
  • ‘readline()’ reads one line at a time from the file.

Q30: Explain how you write to a file in Python.

You can write to a file using the ‘write()’ method:

with open("example.txt", "w") as file:
    file.write("Hello, World!")

Modules and Packages

Q31: What is the difference between a module and a package in Python?

  • A module is a single file that contains the Python code.
  • A package is a collection of modules which is organised in a directory hierarchy.

Q32: How do you create a package in Python?

To create a package, create a directory with an __init__.py file and add your module files:

my_package/
    __init__.py
    module1.py
    module2.py

Q33: What is the purpose of the __init__.py file in a package?

The __init__.py file designates the directory as a package. It can also be used to initialize package-level variables or perform package-specific initialization.

Q34: How do you import specific functions or classes from a module?

Use ‘from’ to import only what you need:

from math import pi, sqrt

Q35: What is the difference between ‘import module’ and ‘from module import *’?

  • ‘import module’ imports the entire module, and you access its contents using dot notation (module.function).
  • ‘from module import *’ imports all names from the module directly into the current namespace, which can lead to naming conflicts.

Advanced Python Concepts

Q36: What are decorators in Python?

Decorators modify the behaviour of other functions or classes:

def uppercase_decorator(func):
    def wrapper():
        result = func()
        return result.upper()
    return wrapper

@uppercase_decorator
def greet():
    return "hello, world"

print(greet())  # Output: HELLO, WORLD

Q37: Explain list comprehensions in Python.

List comprehensions offer a compact method for constructing lists from existing iterables:

squares = [x**2 for x in range(10)]

Q38: What are generators in Python?

Generators are functions that use the ‘yield’ keyword to generate a series of values:

def countdown(n):
    while n > 0:
        yield n
        n -= 1

for num in countdown(5):
    print(num)

Q39: How do you implement multithreading in Python?

The ‘threading’ module provides the foundation for implementing multithreaded applications in Python.

import threading

def print_numbers():
    for i in range(5):
        print(i)

thread = threading.Thread(target=print_numbers)
thread.start()
thread.join()

Q40: What are context managers in Python?

Context managers define the runtime context when executing a ‘with’ statement:

class FileManager:
    def __init__(self, filename):
        self.filename = filename

    def __enter__(self):
        self.file = open(self.filename, 'r')
        return self.file

    def __exit__(self, exc_type, exc_value, traceback):
        self.file.close()

with FileManager('example.txt') as file:
    content = file.read()

Don’t forget that mastering these concepts is only the first step. Python language keeps changing and growing. It is a vast subject requiring continuous learning to be ahead of others. Here at ESS, we have an extensive Python course in both directions. Our training will take you to an expert level to prepare you for Python questions.

Remember, it’s all about understanding the concept behind the questions and then applying them in real-life situations. Start your Python journey with ESS now and begin your path to becoming a Python Expert today!