Python List Exercise with Solutions

Python list is the most widely used data structure, and a good understanding of it is necessary. This Python list exercise aims to help developers learn and practice list operations.

This Python list exercise contains 23 coding questions, each with a provided solution. Practice and solve various list data structure-based programming challenges.

Questions cover the following list topics:

• list operations and manipulations
• list functions
• list slicing
• list comprehension

Let us know if you have any alternative solutions in the comment section below.

• Use Online Code Editor to solve exercise questions.
• Read the Complete guide on Python List to solve this exercise.

Exercise 1: Perform Basic List Operations

Given:

my_list = [10, 20, 30, 40, 50]Code language: Python (python)

Perform following operations on given list

1. Access Elements: Print the third element.
2. List Length: Print the number of elements in the list
3. Check if Empty: Write a code to check is list empty.

Expected Output:

Initial list: [10, 20, 30, 40, 50]

Third item:  30
Length of the list: 5
list is not empty

my_list = [10, 20, 30, 40, 50]
print("Initial list:", my_list)
# Print the third element.
print("Third item: ", my_list[2])
# list size
list_length = len(my_list)
print("Length of the list:", list_length)
# list empty
if list_length == 0:
  print("list is empty")
else:
  print("list is not empty")Code language: Python (python)

Exercise 2: Perform List Manipulation

Given:

my_list = [10, 20, 30, 40, 50]Code language: Python (python)

Perform following list manipulation operations on given list

1. Change Element: Change the second element of a list to 200 and print the updated list.
2. Append Element: Add 600 o the end of a list and print the new list.
3. Insert Element: Insert 300 at the third position (index 2) of a list and print the result.
4. Remove Element (by value): Remove 600 from the list and print the list.
5. Remove Element (by index): Remove the element at index 0 from the list print the list.

Expected Output:

Initial list: [10, 20, 30, 40, 50]

After changing second element: [10, 200, 30, 40, 50]
List after appending 600: [10, 200, 30, 40, 50, 600]
List after inserting 300 at index 2: [10, 200, 300, 30, 40, 50, 600]
List after removing 600 (by value): [10, 200, 300, 30, 40, 50]
List after removing element at index 0: [200, 300, 30, 40, 50]

my_list = [10, 20, 30, 40, 50]
print("Initial list:", my_list)
# Change the second element (at index 1) to 200
my_list[1] = 200
print("After changing second element:", my_list)
# Add 600 to the end of the list
my_list.append(600)
print("List after appending 600:", my_list)
# Insert 300 at index 2
my_list.insert(2, 300)
print("List after inserting 300 at index 2:", my_list)
# Remove 600 from the list (by value)
my_list.remove(600)
print("List after removing 600 (by value):", my_list)
# Remove the element at index 0 (using del)
del my_list[0]
print("List after removing element at index 0:", my_list)Code language: Python (python)

Exercise 3: Sum and average of all numbers in a list

Calculate and print the sum and average of all numbers in a list.

Given:

my_list = [10, 20, 30, 40, 50]Code language: Python (python)

Expected Output:

Sum: 150
Average: 30.0

numbers = [10, 20, 30, 40, 50]
# Calculate the sum
total_sum = sum(numbers)
# Calculate the average
# The average is the sum divided by the number of elements
average = total_sum / len(numbers)
# Print the results
print("Sum:", total_sum)
print("Average:", average)Code language: Python (python)

Exercise 4: Reverse a list

Given:

list1 = [100, 200, 300, 400, 500]Code language: Python (python)

Expected output:

[500, 400, 300, 200, 100]

list1 = [100, 200, 300, 400, 500]
list1.reverse()
print(list1)Code language: Python (python)

list1 = [100, 200, 300, 400, 500]
list1 = list1[::-1]
print(list1)Code language: Python (python)

Exercise 5: Turn every item of a list into its square

Given a list of numbers. write a program to turn every item of a list into its square.

Given:

numbers = [1, 2, 3, 4, 5, 6, 7]Code language: Python (python)

Expected output:

[1, 4, 9, 16, 25, 36, 49]

numbers = [1, 2, 3, 4, 5, 6, 7]
# result list
res = []
for i in numbers:
    # calculate square and add to the result list
    res.append(i * i)
print(res)Code language: Python (python)

numbers = [1, 2, 3, 4, 5, 6, 7]
res = [x * x for x in numbers]
print(res)Code language: Python (python)

Exercise 6: Find Maximum and Minimum

Find and print the largest and smallest number in a list [8, 2, 15, 1, 9].

Given:

data = [8, 2, 15, 1, 9]Code language: Python (python)

Expected Output:

Largest number: 15
Smallest number: 1

# List of numbers
data = [8, 2, 15, 1, 9]
# Find the maximum number
maximum_number = max(data)
# Find the minimum number
minimum_number = min(data)
# Print the results
print("Largest number:", maximum_number)
print("Smallest number:", minimum_number)Code language: Python (python)

Exercise 7: Count Occurrences

Count and print how many times 'Football' appears in list.

Given:

sports = ['Cricket', 'Football', 'Hockey', 'Football', 'Tennis'].Code language: Python (python)

# List of fruits
sports = ['Cricket', 'Football', 'Hockey', 'Football', 'Tennis']
# Count occurrences of 'Football'
football_count = sports.count('Football')
print("Count:", football_count)Code language: Python (python)

Exercise 8: Sort a list of numbers

Sort a given list of numbers in ascending order and print it.

Given: numbers = [5, 2, 8, 1, 9]

Expected Output:

Original list: [5, 2, 8, 1, 9]
Sorted list: [1, 2, 5, 8, 9]

numbers = [5, 2, 8, 1, 9]
print("Original list:", numbers)
# Method 1: Using the sort() method (sorts in-place)
numbers.sort()
print("Sorted list (in-place using .sort()):", numbers)
# Resetting for demonstration of sorted()
numbers = [5, 2, 8, 1, 9]
print("\nOriginal list for sorted() demonstration:", numbers)
# Method 2: Using the sorted() function (returns a new sorted list)
sorted_numbers = sorted(numbers)
print("New sorted list (using sorted()):", sorted_numbers)
print("Original list after sorted() (unchanged):", numbers)Code language: Python (python)

Exercise 9: Create a copy of a list

Create a copy of a list [10, 20, 30] and modify the copy. Print both the original and the copied list to demonstrate they are independent.

original_list = [10, 20, 30]
print("Original list initially:", original_list)
# Create a copy using slicing
# This is a common and concise way to create a shallow copy
copied_list = original_list[:]
# Modify the copied list
copied_list.append(40)
copied_list[0] = 100
print("Original list after modifying copy:", original_list)
print("Copied list after modification:", copied_list)
# Demonstration using list() constructor
another_copy = list(original_list)
another_copy.append(50)
print("\nOriginal list after another_copy modification:", original_list)
print("Another copied list:", another_copy)
# Demonstration using .copy() method (Python 3+)
third_copy = original_list.copy()
third_copy[0] = 999
print("\nOriginal list after third_copy modification:", original_list)
print("Third copied list:", third_copy)Code language: Python (python)

Exercise 10: Combine two lists

Combine given two lists into a single list and print it.

Given:

list_a = [1, 2]
list_b = [3, 4]Code language: Python (python)

Expected Output:

[1, 2, 3, 4]

list_a = [1, 2]
list_b = [3, 4]
# Method 1: Using the + operator (creates a new list)
combined_list_plus = list_a + list_b
print("Combined list (using + operator):", combined_list_plus)
# Method 2: Using the extend() method (modifies list_a in-place)
temp_list = [1, 2]
temp_list.extend(list_b)
print("Combined list (using .extend() on temp_list):", temp_list)
# Method 3: Using unpacking (creates a new list - Python 3.5+)
combined_list_unpacking = [*list_a, *list_b]
print("Combined list (using unpacking *):", combined_list_unpacking)Code language: Python (python)

Exercise 11: Remove empty strings from the list of strings

list1 = ["Mike", "", "Emma", "Kelly", "", "Brad"]Code language: Python (python)

Expected output:

["Mike", "Emma", "Kelly", "Brad"]

list1 = ["Mike", "", "Emma", "Kelly", "", "Brad"]
# remove None from list1 and convert result into list
res = list(filter(None, list1))
print(res)Code language: Python (python)

Exercise 12: Remove Duplicates from list

Write a function that takes a list with duplicate elements and returns a new list with only unique elements.

Given: list_with_duplicates = [1, 2, 2, 3, 1, 4, 5, 4]

Expected Output:

[1, 2, 3, 4, 5]

list_with_duplicates = [1, 2, 2, 3, 1, 4, 5, 4]
unique_elements_set = set(list_with_duplicates)
unique_list = list(unique_elements_set)
print(f"Original list: {list_with_duplicates}")
print(f"List with unique elements: {unique_list}")Code language: Python (python)

Exercise 13: Remove all occurrences of a specific item from a list

Given a Python list, write a program to remove all occurrences of item 20.

Given:

list1 = [5, 20, 15, 20, 25, 50, 20]Code language: Python (python)

Expected output:

[5, 15, 25, 50]

list1 = [5, 20, 15, 20, 25, 50, 20]
# list comprehension
# remove specific items and return a new list
def remove_value(sample_list, val):
    return [i for i in sample_list if i != val]
res = remove_value(list1, 20)
print(res)Code language: Python (python)

list1 = [5, 20, 15, 20, 25, 50, 20]
while 20 in list1:
    list1.remove(20)
print(list1)Code language: Python (python)

Exercise 14: List Comprehension for Numbers

Use list comprehension to create a new list containing only the numbers from a given list.

Given:

my_list = [1, 2, 3, 'Jessa', 4, 5, 'Kelly', 'Jhon', 6]Code language: Python (python)

Expected Output:

[1, 2, 3, 4, 5, 6]

mixed_list = [1, 2, 3, 'Jessa', 4, 5, 'Kelly', 'Jhon', 6]
print(f"Original mixed list: {mixed_list}")
# Use list comprehension to filter for numbers (integers and floats)
# isinstance(item, (int, float)) checks if the item is an integer OR a float
numbers_only_list = [item for item in mixed_list if isinstance(item, (int, float))]
print(f"List containing only numbers: {numbers_only_list}")Code language: Python (python)

Exercise 15: Access Nested Lists

Given a nested list, print the element '55'.

Given:

nested_list = <span style="background-color: initial; font-family: inherit; font-size: inherit; text-align: initial; color: initial;">[[10, 20, 30], [44, 55, 66], [77, 87, 99]]</span>Code language: Python (python)

nested_list = [[10, 20, 30], [44, 55, 66], [77, 87, 99]]
print(f"Nested list: {nested_list}")
# To access 55:
# 1. The list [44, 55, 66] is at index 1 of the main nested_list.
# 2. Within [44, 55, 66], the element 55 is at index 1.
element_55 = nested_list[1][1]
print(f"The element '55' is: {element_55}")Code language: Python (python)

Exercise 16: Flatten Nested List

Write a function to flatten a list of lists into a single, non-nested list. (e.g., [[1, 2], [3, 4]] becomes [1, 2, 3, 4]).

Given:

list_of_lists = [[1, 2], [3, 4], [5, 6, 7]]Code language: Python (python)

Expected Output:

[1, 2, 3, 4, 5, 6, 7]

def flatten_list(nested_list):
 
  flattened = []
  for sublist in nested_list:
    for item in sublist:
      flattened.append(item)
  return flattened
# Alternative and often more Pythonic using list comprehension
def flatten_list_comprehension(nested_list):
  return [item for sublist in nested_list for item in sublist]
# Test cases
list_of_lists = [[1, 2], [3, 4], [5, 6, 7]]
print(f"Original nested list: {list_of_lists}")
flattened_result = flatten_list(list_of_lists)
print(f"Flattened list (using loops): {flattened_result}")
flattened_result_comp = flatten_list_comprehension(list_of_lists)
print(f"Flattened list (using list comprehension): {flattened_result_comp}")Code language: Python (python)

# Alternative and often more Pythonic using list comprehension
def flatten_list_comprehension(nested_list):
  return [item for sublist in nested_list for item in sublist]
# Test cases
list_of_lists = [[1, 2], [3, 4], [5, 6, 7]]
print(f"Original nested list: {list_of_lists}")
flattened_result_comp = flatten_list_comprehension(list_of_lists)
print(f"Flattened list (using list comprehension): {flattened_result_comp}")Code language: Python (python)

Exercise 17: Concatenate two lists index-wise

Write a program to add two lists index-wise. Create a new list that contains the 0th index item from both the list, then the 1st index item, and so on till the last element. any leftover items will get added at the end of the new list.

Given:

list1 = ["M", "na", "i", "Ke"]
list2 = ["y", "me", "s", "lly"]Code language: Python (python)

Expected output:

['My', 'name', 'is', 'Kelly']

list1 = ["M", "na", "i", "Ke"] 
list2 = ["y", "me", "s", "lly"]
list3 = [i + j for i, j in zip(list1, list2)]
print(list3)Code language: Python (python)

Exercise 18: Concatenate two lists in the following order

list1 = ["Hello ", "take "]
list2 = ["Dear", "Sir"]Code language: Python (python)

Expected output:

['Hello Dear', 'Hello Sir', 'take Dear', 'take Sir']

list1 = ["Hello ", "take "]
list2 = ["Dear", "Sir"]
res = [x + y for x in list1 for y in list2]
print(res)Code language: Python (python)

Exercise 19: Iterate both lists simultaneously

Given a two Python list. Write a program to iterate both lists simultaneously and display items from list1 in original order and items from list2 in reverse order.

Given

list1 = [10, 20, 30, 40]
list2 = [100, 200, 300, 400]Code language: Python (python)

Expected output:

10 400
20 300
30 200
40 100

list1 = [10, 20, 30, 40]
list2 = [100, 200, 300, 400]
for x, y in zip(list1, list2[::-1]):
    print(x, y)Code language: Python (python)

Exercise 21: Add new item to list after a specified item

Write a program to add item 7000 after 6000 in the following Python List

Given:

list1 = [10, 20, [300, 400, [5000, 6000], 500], 30, 40]Code language: Python (python)

Expected output:

[10, 20, [300, 400, [5000, 6000, 7000], 500], 30, 40]

list1 = [10, 20, [300, 400, [5000, 6000], 500], 30, 40]
# understand indexing
# list1[0] = 10
# list1[1] = 20
# list1[2] = [300, 400, [5000, 6000], 500]
# list1[2][2] = [5000, 6000]
# list1[2][2][1] = 6000
# solution
list1[2][2].append(7000)
print(list1)Code language: Python (python)

Exercise 22: Extend nested list by adding the sublist

You have given a nested list. Write a program to extend it by adding the sublist ["h", "i", "j"] in such a way that it will look like the following list.

Given List:

list1 = ["a", "b", ["c", ["d", "e", ["f", "g"], "k"], "l"], "m", "n"]
# sub list to add
sub_list = ["h", "i", "j"]Code language: Python (python)

Expected Output:

['a', 'b', ['c', ['d', 'e', ['f', 'g', 'h', 'i', 'j'], 'k'], 'l'], 'm', 'n']

list1 = ["a", "b", ["c", ["d", "e", ["f", "g"], "k"], "l"], "m", "n"]
sub_list = ["h", "i", "j"]
# understand indexing
# list1[2] = ['c', ['d', 'e', ['f', 'g'], 'k'], 'l']
# list1[2][1] = ['d', 'e', ['f', 'g'], 'k']
# list1[2][1][2] = ['f', 'g']
# solution
list1[2][1][2].extend(sub_list)
print(list1)Code language: Python (python)

Exercise 23: Replace list’s item with new value if found

You have given a Python list. Write a program to find value 20 in the list, and if it is present, replace it with 200. Only update the first occurrence of an item.

Given:

list1 = [5, 10, 15, 20, 25, 50, 20]Code language: Python (python)

Expected output:

[5, 10, 15, 200, 25, 50, 20]

list1 = [5, 10, 15, 20, 25, 50, 20]
# get the first occurrence index
index = list1.index(20)
# update item present at location
list1[index] = 200
print(list1)Code language: Python (python)