Python is one of the most important programming language used in almost every field from
development from data analytics to machine learning.. Developers and non-developers alike find
it useful.
Here are few most asked interview questions with their detailed and proper explanation.
1) What is the difference between = and ==?
Answer: “=” is an assignment operator whereas “==” is a comparison operator. “=” is used
to assign a value to any variable while “==” is used to checks whether the given two
operands are equal or not. It checks whether the two variables have the equal content in it
or not. It they are equal; it returns True otherwise it returns False.
2) What is the difference between is and ==?
Answer : “is” is an identity operator while “==” is a comparison operator. “is” checks if
memory addresses are identical which means it checks whether both variables point to the
same object or not . “==” checks if values are equal or not
3) What are break, continue and pass?
Answer: break, continue, and pass are control flow statements. They are used to change the
execution behavior of loops and block of codes.
break terminates the loop immediately and exists the loop.
continue skips current iteration and jumps to next in the loop.
pass does absolutely nothing. It can just act as a placeholder.
4) What is the difference between append(), extend()?
Answer : append() and extend() are list methods , append() adds the object as-is to the end
of the list while extend() terates through the collection and adds each item individually.
Example : sample_list = [1,2,3,4]
Sample_list.append([5,6])
print(sample_list)
Output : [1,2,3,4,[5,6]]
sample_list.extend([5,6]]
print(sample_list)
Output : [1,2,3,4,5,6]
5) Swap two numbers with using temporary variable
Answer : a , b = 10 , 5
b , a = 5 , 10
print(a)
print(b)
6) What is difference between list and tuple?
Answer : List and tuple are data structures in python. List is defined using square brackets
e.g : list _demo = [1,2.5,”hi”,True,5]. They are mutable which means can be changed (add
element , remove or modify) after creation. On the other hand , tuples are created using
round brackets e.g : tuple_demo = (1,2.5,”hi”,False). They are immutable which means
unchangeable.
7) How to remove duplicates from a list ?
Answer : You can remove duplicates from a list simply by converting it into a set using type
casting method because set is a collection of unique elements.
Example : list_demo = [1,2,2,3,4,5,3,5,8,1]
unique_elements = list(set(list_demo)
print(unique_elements)
8) What are *args and **kwargs ?
Answer : *args is called positional arguments and it us used when you want to pass a
varying number of positional arguments to a function. Python packs all these extra
arguments into a tuple.
**kwargs is called keyword arguments. It us used when you want to pass a varying number
of keyworded (named) arguments. Python packs these arguments into a dictionary, where
the keys are the argument names and the values are the argument values.
9) What is class and object in Python ?
Answer : In Python, a class is a blueprint or template for creating objects, while an object is
an instance of that class
10) What is NumPy ?
Answer : NumPy (Numerical Python) is a Python library used for mathematical
computations and working with large multi-dimensional arrays. It is mostly used for
numerical calculations and work with large datasets.
11) What is difference between Python list and NumPy array?
Answer : Python lists are heterogeneous whereas NumPy arrays are homogenous.
Python list does not support element wise operations. It requires looping over the list.
NumPy arrays support element wise operations and hence they are faster for large datasets
as compared to Python list.
12) What is lambda function in Python?
Answer : A lambda function is a small, anonymous (nameless) function in Python that can
take any number of arguments but can only have a single expression.
For example : square_lambda = lambda x: x ** 2.
print(square_lambda(2))
Output : 4
13) What are generators and decorators?
Answer : Generators are iterators which can execute only once.
● Generator uses “yield” keyword.
● Generators are mostly used in loops to generate an iterator
by returning all the values in the loop without affecting the
iteration of the loop.
● Every generator is an iterator.
EXAMPLE:
def sqr(n):
for i in range(1, n+1):
yield i*i
a = sqr(3)
print(next(a))
print(next(a))
print(next(a))
Output:
1
4
9
A decorator is a function in Python used to modify, extend, or wrap the behavior of a
function or class without permanently changing its source code.
Example :
def my_logger(func):
def wrapper():
print("The function is about to start running...")
func() # Executes the original function
print(”The function has finished running.")
return wrapper
@my_logger
def say_hello():
print("Hello, World!")
say_hello()
# Output:
The function is about to start running...
Hello, World!
The function has finished running.
14) What are Panda’s series?
Answer : A Pandas Series is a one-dimensional array that can hold data of any type
(integers, strings, floating-point numbers, Python objects, etc.). It is the fundamental
building block of the Pandas library and is easiest to visualize as a single column in an Excel
spreadsheet or a SQL table
15) What is difference between. loc and. iloc?
Answer : They are both lookup types in Python where .loc stands for label based (column
names, dates, string, etc) and. iloc represents integer based or index based (position of
columns and rows).
These are few Python interview questions but mastering Python does not mean memorizing
the answers only.
The best way to cement this knowledge is to open your IDE, break the code snippets, and
build something small. Good luck with your upcoming interview—you’ve got this!
Author: Chaitali Kate,
Related Links:
Mastering Python Dictionaries.
Python and SQL Interview Questions.
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Chaitali Kate
Expert trainer and consultant at SevenMentor with years of industry experience. Passionate about sharing knowledge and empowering the next generation of tech leaders.