Introduction
Python is a popular programming language that is widely used in many different fields such as web development, data analysis, machine learning, artificial intelligence, and scientific computing. It’s no surprise that many companies are looking for Python developers who have a good understanding of the language and its key concepts. In this blog post, we will take a look at some of the most common interview questions for Python developers and provide examples to help you prepare for your interview.
Most Commonly Asked Questions and their answers in 2023
1. What is Python used for?
Python is a high-level programming language that can be used for a wide range of tasks such as web development, data analysis, machine learning, artificial intelligence, and scientific computing.
2. What is the difference between a list and a tuple in Python?
A list is a mutable data structure that can be modified after it is created, while a tuple is an immutable data structure that cannot be modified. For example:
list_example = [1, 2, 3, 4]
list_example.append(5) # valid
tuple_example = (1, 2, 3, 4)
tuple_example.append(5) # invalid
3. How do you define a function in Python?
In Python, you can define a function using the def keyword followed by the function name and the parentheses that contains the parameters. For example:
def add_numbers(a, b):
return a + b
4. What is the use of the “self” keyword in Python?
In Python, the “self” keyword is used to refer to the instance of a class. It is a convention to use “self” as the first parameter of a class method. For example:
class MyClass:
def __init__(self):
self.x = 0
def increment(self):
self.x += 1
5. What is the difference between “==” and “is” in Python?
The “==” operator is used to compare the values of two objects, while the “is” operator is used to compare the memory addresses of two objects. For example:
a = [1, 2, 3]
b = [1, 2, 3]
c = a
a == b # True
a is b # False
a is c # True
6. How do you handle exceptions in Python?
In Python, you can handle exceptions using a try-except block. For example:
try:
x = 1/0
except ZeroDivisionError:
print("Cannot divide by zero")
7. How do you use modules in Python?
In Python, you can use modules by importing them using the import keyword. For example:
import math
x = math.sqrt(16)
8. What is a decorator in Python?
A decorator is a function that modifies the behavior of another function. In Python, decorators are applied to functions or methods using the “@” symbol. For example:
def my_decorator(func):
def wrapper():
print("Something is happening before the function is called.")
func()
print("Something is happening after the function is called.")
return wrapper
@my_decorator
def say_whee():
print("Whee!")9. What is the difference between a local variable and a global variable in Python?
A local variable is a variable that is defined inside a function and is only accessible within that function, while a global variable is a variable that is defined outside of any function and is accessible throughout the program. For example:
def my_function():
local_var = 1
global_var = 2
my_function()
print(local_var) # will raise an error
10. How do you implement a linked list in Python?
A linked list can be implemented in Python using classes and objects. Each node in the linked list is represented by an object of the Node class, which contains a value and a reference to the next node. For example:
class Node:
def __init__(self, value):
self.value = value
self.next = None
class LinkedList:
def __init__(self):
self.head = None
11. How do you use classes and objects in Python?
In Python, classes are used to define a blueprint for objects, which are instances of the class. Classes contain attributes (variables) and methods (functions) that define the properties and behavior of the object. For example:
class Dog:
def __init__(self, name, breed):
self.name = name
self.breed = breed
def bark(self):
print("Woof!")
my_dog = Dog("Fido", "Golden Retriever")
my_dog.bark() # Output: "Woof!"
12. How do you use inheritance and polymorphism in Python?
Inheritance allows you to define a new class that inherits the properties and methods of an existing class. Polymorphism allows you to use a single method or operator to work with different types of objects. For example:
class Animal:
def __init__(self,name):
self.name = name
def speak(self):
pass
class Dog(Animals):
def speak(self):
return self.name+' says Woof!'
class Cat(Animals):
def speak(self):
return self.name+' says Meow!'
animals = [Dog('Fido'),Cat('Whiskers'),Dog('Buddy')]
for animal in animals:
print(animal.speak())13. What is the difference between deep and shallow copy in Python?
A shallow copy creates a new object with a new reference to the same underlying data, while a deep copy creates a new object with a new copy of the underlying data. For example:
import copy
original_list = [1, 2, 3, [4, 5]]
shallow_copy_list = copy.copy(original_list)
deep_copy_list = copy.deepcopy(original_list)
original_list[3].append(6)
print(original_list) # [1, 2, 3, [4, 5, 6]]
print(shallow_copy_list) # [1, 2, 3, [4, 5, 6]]
print(deep_copy_list) # [1, 2, 3, [4, 5]]
14. How do you use regular expressions in Python?
Regular expressions can be used in Python with the re module. The module provides various functions such as
search, findall, and sub to work with regular expressions. For example:
import re
text = "The phone number of the agent is 408-555-1234. Call soon!"
phone_number = re.search(r"\d{3}-\d{3}-\d{4}", text)
print(phone_number.group()) # Output: "408-555-1234"
15. What is the use of the “yield” keyword in Python?
The “yield” keyword is used in Python to define a generator function. A generator function is a special type of function that can be used to generate a sequence of values. Instead of returning a value, a generator function uses the “yield” keyword to return an iterator that can be used to iterate over the generated values. For example:
def my_generator():
yield 1
yield 2
yield 3
for value in my_generator():
print(value) # Output: 1, 2, 3
Conclusion
These are some of the most common interview questions for Python developers. It is important to note that these are common questions and some may not be asked in every interview, but they are good to know and practice to be prepared for the potential questions that you may encounter during an interview. Good luck with your interview, and happy coding!
