Python Interview Questions And Answers

Do you wish to have a career in software engineering or data science? If yes, then one core thing to do is to ace Python. Both these job fields, and many more, require extensive knowledge and preparation of this language, which can be done by studying the top and most trending Python interview questions and answers.

Due to increasing use of Python in AI and machine learning, this language is rapidly becoming more adopted by various professionals. Python is a general-purpose programming language, which is a great fit for beginners and professionals looking to become a part of the tech world. 

Let's get started with the top Python basic interview questions.

Python Basic Interview Questions

Here are a few key interview questions you must know about to get a great start to your interview.

Question 1. What does dynamically typed language mean?

Answer. Dynamically typed languages are ones that perform type checking during runtime instead of at compile time. Some common examples of these languages are Python, JavaScript, PHP, Ruby, etc.

Question 2. What is PEP 8? Why is it important?

Answer. PEP refers to Python Enhancement Proposal, which is an official design document that delivers information to the Python community. It contains information on new features and processes of this language. PEP 8 is important because it documents all the style guidelines for this code.

Question 3. What is the use of 'self' in Python?

Answer. In Python, self represents the instance of the class. This keyword is used to access the methods and attributes, while binding the attributes with presented arguments.

Question 4. What is an interpreted language?

Answer. Interpreted languages are ones that execute its statements line by line. Python, PHP, JavaScript, Ruby, and R are top examples. A program written in an interpreted language will directly run from the source code without any intermediary compilation step.

Question 5. What is the difference between a Dictionary and Set?

Answer. A dictionary refers to an ordered collection of data values, which is utilized for storing data values such as a map.

Set refers to an unordered collection of data types. It is mutable, iterable, and does not have any duplicate elements.

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Python Technical Interview Questions

Are you going for an interview wherein you could be asked technical questions too? Worry not! Here are some commonly asked Python technical interview questions for you.

Question 6. What is pass in Python?

Answer. The pass keyword in Python represents a null operation without which we may find ourselves in some errors during code execution. It is mostly used to fill up an empty block of code that may execute during runtime but has not been written yet.

Question 7. What is _ _init_ _?

Answer. _ _init_ _ refers to a constructor method, which is called automatically to allocate memory as a new instance/ object gets created. The _ _init_ _ method is associated with all classes as it aids them in distinguishing attributes and methods of a class from all local variables.

Question 8. Which program can be used to print a pyramid asterisk pattern?

Answer. Here's the code:

1 n = 5
2 k = 0
3 for i in range(1, n+1):
4 for j in range(1, (n-i)+1):
5 print(end=" ")
6
7 while k!=(2*i-1):
8 print("*", end="")
9 k += 1
10 
11 k = 0
12 print()

Question 9. Give a simple example of how a file can be read using Python.

Answer. Here's a simple example:

1 file = open('sample.txt', 'r')
2
3 print(file.read())
4  
5 file.close()
6 Output:
7 igmGuru is a globally recognized
8 ed-tech giant

Question 10. Which program can remove duplicates from a list?

Answer. The program to remove duplicates from a list is quite simple:

1 dupl = [1,1,0,0,1,0,2,0,3,2,2,4,4,2,3]
2 dupl = set(dupl)
3 dupl = list(dupl)
4 print(dupl)

Output:
[0, 1, 2, 3, 4]

Python Interview Questions for Data Engineer

This programming language plays a significant role in the field of data engineering. Hence, these Python interview questions for data engineers will help you get a better idea of what not to miss.

Question 11. What is data smoothing? How is it done?

Answer. The approach of data smoothing is employed to eliminate any outliers from data sets. The goal is to reduce extra noise and ensure that the patterns are recognizable.

Question 12. What is the difference between == and 'is' operators in Python?

Answer. The == operator is used for comparing the equality of objects, while 'is' is used for finding out whether different variables point towards the same object in memory.

Example:
a = 4
b = 4
print(a is b)
print(id(a))
print(id(b))

Output:
True
1644840201
1642650272

Question 13. How to easily remove duplicates from a Python list?

Answer. The easiest way to remove duplicates from a list is by converting it into a set. This is because sets do not consist of any duplicate data. Once done, you can reconvert it into a list.

list1 = [3,6,7,9,2,3,7,1]
list2 = list(set(list1))

The result for list2 will contain [3,6,7,9,2,1]. However, it is not compulsory that the list order would stay untouched.

Question 14. Write a function for creating a queue and displaying all the sizes and members of it. 

Answer. Here is a sample code you can use:

import queue
q = queue.Queue()
for x in range(4):
    q.put(x)
print("Members of the queue:")
y=z=q.qsize()
 
for n in list(q.queue):
    print(n, end=" ")
print("\nSize of the queue:")
print(q.qsize())

Question 15. How to rename columns in Pandas?

Answer. The rename() function can be used to rename columns in Pandas. Any column in a dataframe can be renamed with this.

customers.rename(columns=dict(user_id_number="user_id", customer_phone="phone")

You May Also Read- Python Tutorial

Python Coding Interview Questions

There are very high chances that you would be asked some Python coding interview questions, especially if you are not going at a beginner level. Take the aid of these questions to prepare to ace it.

Question 16. Write a program to print this pattern.

Answer. The program is:

def alphapat(n):
    num = 65
    for i in range(0, n):
        for j in range(0, i+1):
            ch = chr(num)
            print(ch, end=" ")
        num = num + 1
    
        print("\r")
n = 5
alphapat(n)

Question 17. Write a program to print this pattern.

Answer. The program is:

def myfunc(n):
    k = n - 1
    for i in range(0, n):
        for j in range(0, k):
            print(end=" ")
        k = k - 1
        for j in range(0, i+1):
            print("* ", end="")
        print("\r")
n = 5
myfunc(n)

Question 18. How can you find the GCD of two numbers?

Answer. We can use this program for finding the GCD of two numbers:

def gcd(a, b):

    if (a == 0):
        return b
    if (b == 0):
        return a

    if (a == b):
        return a

    if (a > b):
        return gcd(a-b, b)
    return gcd(a, b-a)

a = 98
b = 56
if(gcd(a, b)):
    print('GCD of', a, 'and', b, 'is', gcd(a, b))
else:
    print('not found')

Question 19. How can we check if provided strings are anagram or not?

Answer. We can find it with the given program:

def check(s1, s2):
    
    if(sorted(s1)== sorted(s2)):
        print("The strings are anagrams.")
    else:
        print("The strings aren't anagrams.")        
        
s1 = input("Enter string1: ")
# input1: "listen"
s2 = input("Enter string2: ")
# input2: "silent"
check(s1, s2)
# Output: the strings are anagrams.

Question 20. Is it possible to find whether the given number is negative or positive?

Answer. Yes, it is possible by using the right program.

num = float(input("Enter a number: "))
# Input: 1.2
if num > 0:
   print("Positive number")
elif num == 0:
   print("Zero")
else:
   print("Negative number")

#output: Positive number

Python Programming Interview Questions

These Python programming interview questions will help you get a better understanding of the nature of questions that can be asked during your interview.

Question 21. Which program can be used to check whether a string is a palindrome or not?

Answer. The program to check if a string is a palindrome or not is:

def is_palindrome(string):
   reversed_string = string[::-1]
   return string == reversed_string

# Test the function
word = "madam"
if is_palindrome(word):
   print(f"{word} is a palindrome")
else:
   print(f"{word} is not a palindrome")

Question 22. How can a string be reversed?

Answer. A string can be reversed with this program:

def reverse_string(string):
   return string[::-1]

# Test the function
text = "Hello, World!"
reversed_text = reverse_string(text)
print(reversed_text)

Question 23. How can we check whether a number is prime or not?

Answer. We can use this program to check whether a number is prime or not:

def is_prime(number):
   if number < 2:
       return False
   for i in range(2, int(number**0.5) + 1):
       if number % i == 0:
           return False
   return True

# Test the function
num = 17
if is_prime(num):
   print(f"{num} is a prime number")
else:
   print(f"{num} is not a prime number")

Question 24. How can we find the factorial of a number?

Answer. This program can be used:

def factorial(n):
   if n == 0:
       return 1
   else:
       return n * factorial(n-1)

# Test the function
number = 5
result = factorial(number)
print(f"The factorial of {number} is {result}")

Question 25. Which program can be used to count the frequency of every single element in a list?

Answer. This program can be used:

def count_frequency(numbers):
   frequency = {}
   for num in numbers:
       if num in frequency:
           frequency[num] += 1
       else:
           frequency[num] = 1
   return frequency

# Test the function
nums = [1, 2, 3, 2, 1, 3, 2, 4, 5, 4]
frequency_count = count_frequency(nums)
print(frequency_count)

Python Interview Questions for Experienced Professionals

Python interview preparation is important even for those who are experienced professionals. Here are a few important Python interview questions to help you out.

Question 26. What is Scope Resolution?

Answer. There are many times when a few objects that are within the same scope share the same name even though they function differently. This is where scope resolution automatically comes into the play.

For instance, modules named 'math' and 'cmath' have plenty of common functions, like exp(), acos(), and log10(). This ambiguity can be solved by adding the respected prefixes along, like math.acos() and cmath.acos().

Question 27. What do generators mean in Python?

Answer. Generators refer to functions that can return an iterable accumulation of items in a set manner, one at a time. Generally speaking, they are employed for creating iterators with distinct approaches. The yield keyword is used instead of return to return  a generator object.

Here is a program to help you build a generator for fibonacci numbers:

## generate fibonacci numbers upto n
def fib(n):
   p, q = 0, 1
   while(p < n):
       yield p
       p, q = q, p + q
x = fib(10)    # create generator object 
 
## iterating using __next__(), for Python2, use next()
x.__next__()    # output => 0
x.__next__()    # output => 1
x.__next__()    # output => 1
x.__next__()    # output => 2
x.__next__()    # output => 3
x.__next__()    # output => 5
x.__next__()    # output => 8
x.__next__()    # error
 
## iterating using loop
for i in fib(10):
   print(i)    # output => 0 1 1 2 3 5 8

Question 28. How do arguments get passed in Python?

Answer. Arguments get passed in two ways - value and reference. Here is more about them.

• Pass by value: This is how the copy of the actual object is passed. If the value of the copy is changed, it will not affect the value of the original object.
• Pass by reference: This is how the reference of the actual object is passed. If the value of the new object is changed, it will affect the value of the original object.

def appendNumber(arr):
   arr.append(4)
arr = [1, 2, 3]
print(arr)  #Output: => [1, 2, 3]
appendNumber(arr)
print(arr)  #Output: => [1, 2, 3, 4]

Question 29. What is monkey patching in Python?

Answer. Monkey patching in Python is a code that modifies or further extends other code at the runtime. It is usually done at the startup.

# g.py
class igmguru:
   def function(self):
       print "function()"

import m
def monkey_function(self):
   print "monkey_function()"

m.igmguru.function = monkey_function
obj = m.igmguru()
obj.function()

Question 30. Which code can be used to display the current time?

Answer. Use this code:

currenttime= time.localtime(time.time())
print (“Current time is”, currenttime)

Conclusion

There are endless Python interview questions but learning them all is not possible. To help you ace your interview, these are enough. The ones here are integral to help you begin and show you the path ahead. Learning from the best will aid you further in getting your dream job.

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