Interview Preparation

Top Python Interview Questions & Answers For 2021


Q1. What is Python?

Python is a high level, interpreted and multi-paradigm programming language. It combines the features of C and Java programming language. It offers very elegant style of developing programs like C. And like Java, it offers object-oriented features, so that a programmer can use classes and objects.

Python is open source software. It is freely available to all to download and use it to develop programs.


Q2. What are the features of Python programming?

There are several features due to which Python is preferred over other programming language. Some of the important features of Python have been mentioned below:

  • Python is easy
  • Easy to learn
  • Python lets us to build more functions with fewer lines of code
  • Python is perfect for building prototypes.
  • Python is flexible.
  • It has a ton of resources.
  • Python is open-source.
  • Python provide interfaces to all major commercial databases.
  • Python supports GUI applications.
  • It supports functional and structured programming methods as well as OOP.
  • Python can be used as scripting language.
  • It can be easily integrated with C, C++, COM, ActiveX etc.

Q3. Explain execution of a Python program?

Please refer: Execution of a Python Program


Q4. What are the different flavors of Python?

Flavors of Python means different types of Python compiler. These different types of flavors/compilers are useful in integrating other programming languages with Python.

  • CPython: Standard Python compiler implemented in C language.
  • Jython: Python programming language designed to implement and run using Jython in Java platform. Earlier knows as JPython.
  • IronPython: This is the implementation of Python language for .NET framework.
  • PyPy: This is a Python implementation using Python language.
  • RubyPython: This works as a bridge in the Ruby and the Python interpreters.
  • StacklessPython: Tiny programs which should run individually are called tasklets.
  • Pythonxy: This is the Python implementation that add some scientific and engineering related packages.
  • AnacondaPtyhon: Python is redeveloped for managing large-scale data processing and predictive analytics and scientific computing, it is called Anaconda Python.

Q5. What is numpy in Python?

Python supports only a single dimensional arrays. So, in order to use multi-dimensional arrays, we need a special package called Numerical Python package or numpy.


Q6. What is Docstrings in Python?

In Python, only single line comments are allowed. In order to user multiple line comments we use the comments enclosed in triple double quotes(“””) or triple single quotes(”’). This is actually not multiple comments but they are regular strings with the exception that they can span multiple lines. Using triple single quotes(”’) or triple double quotes(“””) occupy memory internally and would waste time of the interpreter since interpreter will have to check them.


Q7. What are the sequences in Python?

A sequence in Python represents a group of elements or items. There are mainly six types of sequences in Python:

  • str
  • bytes
  • bytearray
  • list
  • tuple
  • range

Q8. What are the user-defined datatypes in Python?

The datatypes which are created by the programmers are called ‘user-defined’ datatypes. An array, a class or a module is user-defined datatypes.


Q9. What is the difference between list and tuples in Python?

LISTTUPLES
Lists are mutable. Tuples are immutables
List iteration is time consuming so it’s slower.Tuples iteration is faster as compared to lists, hence it is fast than list.
List supports insertion and deletion operation.Tuple is immutable so it supports only read only operation like accessing elements operation.
List consumes more memoryTuples consume less memory as compared to list.
List have numbers of in-built methods for list operations.Tuples have less in-built methods to perform operation on its elements.
More changes to get errors in case of list.In tuples, it is less changes to get error.

Q10. How is memory managed in Python?

Please refer: Memory Management in Python


Q11. What is the difference between a module and a package in Python?

Each Python program file is a module and it imports other modules like objects and attributes. So, a module structure the python program. And the folder of Python program which holds these module files is called package of modules.


Q12. What is sets in Python and where it is used in real world projects?

A set is a collection of both unordered and unindexed sequence of elements or items.

The Python sets are very useful in projects while doing math operations like unions and intersections. It removes the duplicates values from a collection.


Q13. Is python case sensitive?

Yes, Python is a case-sensitive programming language.


Q14. What is the basic difference between Python Arrays and lists?

Arrays and lists are similar in data storing technique. However, an array can contains only a similar datatype elements whereas the list can hold any data type elements within it.


Q15. How will you capitalize the first letter of string?

The capitalize() method capitalize the first letter of a string in python.


Q16. What are the positive and negative indices?

In Python, the positive indices are applied to search in a sequence from right to left. Whereas in negative indices, the searching begins from right to left. For example – in the array of size n, the positive index will start from 0 to n-1. However, in negative indices searching begins from -1 to -(n-1).


Q17. What is the pass statement in Python?

Please refer: The Pass statement


Q18. How do you get a list of all the keys in a dictionary?

In order to get the list of all the keys used in a dictionary, we use the function keys().

>>> my_dict={'a':1,'b':2,'c':3,'e':5}
>>> my_dict.keys()

Q19. What is slicing?

Python allows a string slicing by specifying start and the end index.

stringname[start:stop:stepsize]
  • Default step size is considered 1.
  • If ‘start’ and ‘stop’ value not provied in the slicing syntax. Then slicing is done from 0th to (n-1)th elements.

Let understand with the help of example-

str = 'Learn Python'
print(str[0:5:1])
str = 'Learn Python'
print(str[0:5:2])
str = 'Learn Python'
print(str[::])
str = 'Learn Python'
print(str[::2])
str = 'Learn Python'
print(str[2::])
str = 'Learn Python'
print(str[:4:])
#Output
Learn
Lan
Learn Python
LanPto
arn Python
Lear

Q20. Please explain 10 built-in functions in Python.

complex() – Returns a complex number.

>>> complex(4.5,5)
(4.5+5j)

eval() – Parses a string as an expression.

>>> eval('print(max(25,22.0)-min(7,5))')
20

filter() – filter function excludes items in an iterable object.

# list of letters
letters = ['a', 'b', 'd', 'e', 'i', 'j', 'o']

# function to filter vowels only
def filter_vowels(letter):
    vowels = ['a', 'e', 'i', 'o', 'u']

    if(letter in vowels):
        return True
    else:
        return False

filtered_vowels = filter(filter_vowels, letters)

print('The filtered vowels are:')
for vowel in filtered_vowels:
    print(vowel)

float() – converts a integer or compatible values to float.

>>> float(2)
Output
2.0

frozenset() – It freezes the list and make it immutable.

fruits_list = ['apple', 'banana', 'cherry']
x = frozenset(fruits_list )
print(x)

help() – It will open detail information about module, keywords, symbol or topics.

input() – Accept input from user and return the string.

len() – Returns the length of an object.

>>> a = {1,2,2,3}
>>> print(len(a))
3

max() – Returns the highest value of all in a sequence.

>>> max(2,1,4)
4

min() – Returns the lowest value among all in a sequence.

>>> min(2,1,4)
1

print() – Prints the specified message on the screen.