Python: 25 List Programming interview questions and answers

Interview Question

In this post, we will learn the 25 List Programming interview questions and answers.

1.Program to find the max, min number from the list user input.

listlang = []
numbers = int(input('enter the number of items in list '))
for num in range(numbers):
    item = int(input('Entered number '))
    listlang.append(item)
print('entered list =',listlang)
print("Max number = :", max(listlang), "\nMin number :", min(listlang))

Output

enter the number of items in list 4
Entered number 12
Entered number 34
Entered number 45
Entered number 67
entered list = [12, 34, 45, 67]
Max number = : 67 
Min number : 12

2. Code to remove duplicate from list using List comprehension 

lstnum = [12, 36, 56, 36, 36, 50, 56, 12] 
 
unique_lst = [] 
[unique_lst.append(ele) for ele in lstnum if ele not in unique_lst] 
   
print ("unique elements list  : " ,unique_lst)

Output

unique elements list  :  [12, 36, 56, 50]

3. Program to find the sum of list elements.

lstnum = [12, 36, 56, 36, 36, 50, 56, 12] 

sum = 0

for ele in range(0, len(lstnum)): 
    sum = sum + lstnum[ele] 

print ("sum of list items: " ,sum)

Output

sum of list items  :  294

4. How to Multiply all the elements of list

lstnum = [6, 2, 3, 1, 10, 4] 
mutiply =1;
for ele in lstnum:
  mutiply =  mutiply* ele 

print ("multiplication of list items  : " ,mutiply)

Output

multiplication of list items  :  1440

5.Program to generate a number list between two ranges.

listnum = list(range(1, 7))

print ("list between two range : " ,listnum)

Output

list between two range :  [1, 2, 3, 4, 5, 6]

6.How to reverse the List using slice

listnum = [45,67,12,14,56,87]
reverselist =listnum[::-1]
print ("reverselist : " ,reverselist)

Output

reverselist :  [87, 56, 14, 12, 67, 45]

7.How to flatten a list of lists with a list comprehension

listnum = [[5,6,7,'C#'], ['C++',2,3]]

flatten_list = [ele for sublist in listnum for ele in sublist]

print('flatten list =',flatten_list)

Output

flatten list = [5, 6, 7, 'C#', 'C++', 2, 3]

8.How to Intersect two list

listnum = ['C++',2,3,6,7,5,'C#']
listnum1 = ['C++',5,6,7,'C#']

intersect_res = [item for item in listnum if item in listnum1]

print('intersect of two list =',intersect_res)

Output

intersect of two list = ['C++', 6, 7, 5, 'C#']

9.Program to shuffle a list and print

from random import shuffle
listnum = ['Rust','go','C++',2,3,6,7,5,'C#']

shuffle(listnum)


print('list after shuffling =',listnum)

Output

list after shuffling = [6, 5, 'go', 'C#', 2, 3, 'Rust', 7, 'C++']

10. Program to convert a list into string

listlang = ['This','is','list','Code']
listtostring = ' '.join(listlang)

print('list after shuffling =',listtostring)

Output

list after shuffling = This is list Code

11.How to get the square of each list element between two range

listnum = list(range(3,9))

list_item_square = [ele ** 2 for ele in listnum]
		
print(list_item_square)

Output

[9, 16, 25, 36, 49, 64]

12. Program to get the difference between two List using comprehension 

lstnum = [15, 78, 4]
lstnum1 = [80, 4, 89]

two_list_differnce = [ele for ele in lstnum if ele not in lstnum1]


print(two_list_differnce)

Output

[15, 78]

13. How to count the number of list in list of list.

lstlng = [[15, 78, 4],['C#',80,7],['Go','Rust','C++'],['Python',12]]

print('count of list of list = ',len(lstlng))

Output

count of list of list =  4

14. How to get the first element from each nested list of a list

lstlng = [[15, 78, 4],['C#',80,7],['Go','Rust','C++'],['Python',12]]
each_list_element = [item[0] for item in lstlng] 

print('first element of each nested list  = ',each_list_element)

Output

first element of each nested list  =  [15, 'C#', 'Go', 'Python']

15. How to count occurrence of repeated element in list

from collections import Counter 
lstlng = [15, 18, 14,'C#',18,15,'C#','C++','C++','Python',15]

repeation_of_element  = Counter(lstlng) 
print( repeation_of_element)

Output

Counter({15: 3, 18: 2, 'C#': 2, 'C++': 2, 14: 1, 'Python': 1})

16. How to Filter even values from a list using list comprehension

lstnum = [12, 18, 14,18,15,6]


  
even_element_list = [ele for ele in lstnum  if ele%2 == 0] 
  

print('even item list =',even_element_list)

Output

even item list = [12, 18, 14, 18, 6]

17.How to Sort a list of integers in descending order

lstnum = [12, 18, 14,25,15,6]

lstnum.sort(reverse=True)  

print('list sorting in descending order =',lstnum)

Output

list sorting in descending order = [25, 18, 15, 14, 12, 6]

18.How to Sort a list of integers in ascending order

sort() method used to sort the list in ascending order.

lstnum = [12, 18, 14,25,15,6]

lstnum.sort()  

print('list sorting in ascending order =',lstnum)

Output

list sorting in ascending order = [6, 12, 14, 15, 18, 25]

19. How to remove elements in a list before a specific index

lstnum = [12, 18, 14,25,15,6]

new_list = lstnum[4:]

print('removinfg  element before specific Index =' ,new_list)

Output

removing  element before specific Index = [15, 6]

20.How to remove empty strings from the list of strings

liststr = ["Python", "", "list", "first", "", "example"]

lstafter_remove_empty = list(filter(None, liststr))

print(lstafter_remove_empty)

Output

['Python', 'list', 'first', 'example']

21.How to sort two lists simultaneously 

lstnum = [ 5,2, 1, 7,26]
lstnum1 = [45,35, 78, 80, 100]

lstnum, lstnum1 = zip(*sorted(zip(lstnum, lstnum1)))
print(lstnum, lstnum1)

Output

(1, 2, 5, 7, 26) (78, 35, 45, 80, 100)

23.How to concatenate two list element wise/index-wise.

lststr = ["th", "i", "Pyth", "exa"] 
lststr1 = ["is", "s", "on", "mple"]
concate_list = [i + j for i, j in zip(lststr, lststr1)]
print('concatenated list = ',concate_list)

Output

concatenated list =  ['this', 'is', 'Python', 'example']

24. How to concatenate every element across lists using list comprehension 

lststr = ["this",  "Python"] 
lststr1 = ["is", "example", "of"]
templst = [(x, y) for x in lststr for y in lststr1] 
  
concate_list = [x + ' ' + y for (x, y) in templst] 

print('concatenated list = ',concate_list)

Output

concatenated list =  ['this is', 'this example', 'this of', 'Python is', 'Python example', 'Python of']

25.How to remove negative values from a list with the filter function

lstnum = [-5, 27, 1000, -4, 0, -80,56,-67]
//Removing negative values
res_lst = [item for item in lstnum if item >= 0] 
print('list after removing negative values =',res_lst)

Output

list after removing negative values = [27, 1000, 0, 56]