Python Interview Programs

Hello Techies,

This blog is about the “Python Interview Program”. In this blog, we will see what kind of basic programs are asked by the interviewer in the Python interview program round or the general Python coding interview round.

If you practice these basic python programming questions for the interview, then this will help you in cracking the coding interview python round.

I have also covered Pattern-based program and Python Turtle library-based programs.

So let’s start with the blog and get ready to tackle the Python programming interview questions.

Different Python Interview Programs

#1. Prime Number Program In Python

This is a frequently asked Python interview program in the technical round. So let’s check the program with its output.

num = 88

# To take input from the user
# num = int(input("Enter a number: "))

# prime numbers are greater than 1
if num > 1:
    # check for factors
    for i in range(2, num):
        if (num % i) == 0:
            print(num, "is not a prime number")
            break
    else:
        print(num, "is a prime number")

#if the input number is less than
 or equal to 1,it is not prime
else:
    print(num, "is not a prime number")

Output:

88 is not a prime number

#2. Even number using list comprehension in python

For this program, the interviewer may ask you to write this program using list comprehension. So let’s check the coding for this program.

# list comprehension
even_no = [i for i in range(1,20) if i%2==0]
 
print(Result:, even_no)

Output:

Result: [2, 4, 6, 8, 10, 12, 14, 16, 18]

#3. Check given number is odd or even in python

num = 89

# To take input from the user
# num = int(input("Enter a number: "))

if (num % 2) == 0:
        print(num, "is a even number")
else:
    print(num, "is a odd number")

Output:

89 is a odd number

#4. Python dictionary sorting in descending order based on values

In this type of program, we sort the dictionary in descending order based on the values declared in the dictionary. This is one of the Python interview programs that was asked in the technical round.

Method 1:

dict1 = {'Nikhil': {'English': 5, 'Maths': 2, 'Science': 14},
         'Akash': {'English': 15, 'Maths': 7, 'Science': 2},
         'Akshat': {'English': 5, 'Maths': 50, 'Science': 20}}

def asc(dic):
    dict2 = {}
    for key, val in dic.items():
        dict3 = {}
        sort_val = dict(sorted(val.items(), key=lambda item: item[1], reverse=False))
        dict3.update(sort_val)
        dict2.update({key: dict3})
    return dict2

print(asc(dict1))

Output:

{'Nikhil': {'Maths': 2, 'English': 5, 'Science': 14}, 'Akash': {'Science': 2, 'Maths': 7, 'English': 15}, 'Akshat': {'English': 5, 'Science': 20, 'Maths': 50}}

Method 2:

import operator

list1 = [[31, 60], [10, 10], [30, 20], [20, 25], [45, 30]]
dict1 = dict(list1)
sort_obj = dict(sorted(dict1.items(), key=operator.itemgetter(1), reverse=False))
mylist = []

for k, v in sort_obj.items():
    mylist.append([k,v])
print(mylist)

Output:

[[10, 10], [30, 20], [20, 25], [45, 30], [31, 60]]

Method 3:

print(sorted(list1, key=lambda arg:arg[1]))

Output:

[[10, 10], [30, 20], [20, 25], [45, 30], [31, 60]]

#5. Compare two lists in python and return matches in python

a = [1, 1, 2, 3, 5, 8, 13, 30, 55]
b = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 10, 13]

print(set(a) & set(b))

Output:

{1, 2, 3, 5, 8, 13}

#6. How to Remove Duplicates From a Python List

mylist = [1, 1, 2, 3, 5, 8, 13, 21, 21, 55, 21]
unique = set(mylist)
print(unique)

Output:

{1, 2, 3, 5, 8, 13, 21, 55}

#7. How to Reverse a List in Python

Method 1: Using Slicing

#Method1: Using Slicing

mylist = [1, 2, 3, 5, 8, 13, 21, 55]
result = mylist[::-1] # using slicing
print(result)

Output:

[55, 21, 13, 8, 5, 3, 2, 1]

Method 2: Using the reverse method

list2 = ['a', 'b', 'c', 'd', 'a', 'a']
list2.reverse()
print (list2)

Output:

['a', 'a', 'd', 'c', 'b', 'a']

#8. How to reverse a string in Python: 5 Different way

Method 1: Using slice revers method

string = "abc"
result = string[::-1]
print(result)

Output:

cba

Method 2: Using Python built-in function reversed & join method

string = "abc"
string = "".join(reversed(string))
print(string)

Output:

cba

Method 3: Using For Loop

def reverse_for_loop(s):
    i = ''
    for c in s:
        i = c + i  # appending chars in reverse order
    return i

input_str = 'python'
obj = reverse_for_loop(input_str)
print(obj)

Output:

nohtyp

Method 4: Using while loop

def reverse_while_loop(s):
    i = ''
    length = len(s) - 1
    while length >= 0:
        i = i + s[length]
        length = length - 1
    return i

input_str = 'python'
obj = reverse_while_loop(input_str)
print(obj)

Output:

nohtyp

Method 5:

str1 = "this is new statement"

def get_reverse_string(new_string):
    reversed_string = ""
    total_count = len(new_string) - 1
    for i in range(0, len(new_string)):
        reversed_string += new_string[total_count-i]
    return reversed_string

print(get_reverse_string(str1))

Output:

'tnemetats wen si siht'

#9. How to make a string palindrome in Python

Method 1:

def isPalindrome(s):
    if s.lower() == s[::-1].lower():
        print("Yes")
    else:
        print ("No")

s = "Nitin"
result = isPalindrome(s)

Output

Yes

Method 2:

def isPalindrome(str):
    # Run loop from 0 to len/2
    for i in range(0, int(len(str) / 2)):
        if str[i] != str[len(str) - i - 1]:
            return False
    return True

# main function
s = "Nitin"
ans = isPalindrome(s)

if (ans):
    print("Yes")
else:
    print("No")

Output:

No

#10. Find the Second Largest Number in a list in Python

Method 1: Using Python’s built-in sort function

mylist = [12,45,78,60,98,95]
mylist.sort()
print("The Second largest number is:", mylist[-2])

Output:

The Second largest number is: 95

Method 2: Using Python’s built-in method set & remove

mylist = [12,45,78,60,98,95]
new_list = set(mylist)
new_list.remove(max(new_list))
print("The Second Largest number is", max(new_list))

Output:

The Second Largest number is 95

Method 3:

mylist = [1,2,3]
largest = mylist[0]
second_largest = mylist[0]

for i in range(1, len(mylist)):
    if mylist[i]> largest:
        second_largest=largest
        largest=mylist[i]
    elif mylist[i]>second_largest:
        second_largest=mylist[i]

print("The Second Largest number is", second_largest)

Output:

The Second Largest number is 2

#11. Get repeated item count from list Python

Method 1: Using Python’s collection module

from collections import Counter
mylist = [1,1,1,8,7,8,1,2,9,2]
result = dict(Counter(mylist))
print(result)

Output:

{1: 4, 8: 2, 7: 1, 2: 2, 9: 1}

Method 2: Using count with dict comprehension and count method.

result={k:mylist.count(k) for k in mylist}
print (result)

Output:

{1: 4, 8: 2, 7: 1, 2: 2, 9: 1}

#12. Get item index from list Python

mylist = [2,3,1,22,1]
result = [i for i, x in enumerate(mylist) if x == 1]
print(result)

Output:

[2, 4]

#13. How do you swap two variables without using a third variable in Python?

Method 1:

a = 10
b = 20
print("Before swapping value of a is", a , "and b is", b)

#code to swap a & b
a, b = b, a
print("After swapping value of a is", a , "and b is", b)

Output:

Before swapping value of a is 10 and b is 20  
After swapping value of a is 20 and b is 10 

Method 2: Using addition & subtraction operators

This method only works for numeric values.

a = 100
b = 202
print("Before swapping value of a is", a , "and b is", b)

#code to swap a & b
a = a + b #30
b = a - b #10
a = a - b #20
print("After swapping value of a is", a , "and b is", b)

Output:

Before swapping value of a is 10 and b is 20
After swapping value of a is 20 and b is 10

Method 3: Using Bitwise XOR operator

a = 10
b = 20
print("Before swapping value of a is", a , "and b is", b)

#code to swap a & b
a = a ^ b
b = b ^ a
a = b ^ a
print("After swapping value of a is", a , "and b is", b)

Output:

Before swapping value of a is 10 and b is 20
After swapping value of a is 20 and b is 10

#14. Get count of all elements from the list using oops concept

a = ['a', 'b', 'a', 'aaa', 1, 2, 1, 1]


class CheckCount(object):

    def __init__(self, data_list):
        self.data_list = data_list

    def get_count_keys(self):
        count_dict = {}
        for i in self.data_list:
            if i not in count_dict:
                count_dict[i] = 0
            count_dict[i] = count_dict[i] + 1
        return count_dict

    @staticmethod
    def print_count_values(count_dict):
        for key in count_dict:
            print(key, " - ", count_dict.get(key))


chk_count = CheckCount(a)
new_dict = chk_count.get_count_keys()
chk_count.print_count_values(new_dict)

Output:

a  -  2
b  -  1
aaa  -  1
1  -  3
2  -  1

#15. Find the largest combination from given list

Method 1:

from itertools import permutations
num_list = [99, 89, 992, 743, 9]
latest_largest_num = "0"
new_list = []
for per in permutations(str(number) for number in num_list):
  new_list.append(''.join(per))
latest_largest_num = max(new_list, key=int)
print(latest_largest_num)

Output:

99999289743

Method 2:

from functools import cmp_to_key

def get_key(first, sec):
  if str(first) + str(sec) > str(sec) + str(first):
    return -1
  return 1

num_list = [99, 89, 992, 743, 9]
latest_largest_num = "0"
new_list = sorted(num_list, key=cmp_to_key(get_key))
latest_largest_num = "".join(str(num1) for num1 in new_list)
print(latest_largest_num)

Output:

99999289743

#16. Linked List implementation

# A single node of a singly linked list
class Node:
  # constructor
  def __init__(self, data = None, next=None): 
    self.data = data
    self.next = next

# A Linked List class with a single head node
class LinkedList:
  def __init__(self):  
    self.head = None
  
  # insertion method for the linked list
  def insert(self, data):
    newNode = Node(data)
    if(self.head):
      current = self.head
      while(current.next):
        current = current.next
      current.next = newNode
    else:
      self.head = newNode
  
  # print method for the linked list
  def printLL(self):
    current = self.head
    while(current):
      print(current.data)
      current = current.next

# Singly Linked List with insertion and print methods
LL = LinkedList()
LL.insert(3)
LL.insert(4)
LL.insert(5)
LL.printLL()

Output:

3
4
5

FAQ on Python interview program

I hope you understand every program I have included in this blog. If you need coding for other programs, leave a comment below. Also, share this blog with your friends who are looking for the Python interview program.