This data structure exercise is for beginners to understand and practice basic data structure in Python. Practice Python List, Set, Dictionary, and Tuple questions.
The data structure is widely used to hold any data. To perform any programming tasks in Python, good knowledge of data structure is a must.
Solve this exercise to have a good understanding of basic data structure in Python
This Exercise includes the followings
- The exercise contains 10 questions and solution provided for each question
- Questions cover list manipulation, dictionary, set, and tuple methods.
Use Online Code Editor to solve exercise questions.
Exercise 1: Create a list by picking an odd-index items from the first list and even index items from the second
Given two lists, l1 and l2, write a program to create a third list l3 by picking an odd-index element from the list l1 and even index elements from the list l2.
Given:
l1 = [3, 6, 9, 12, 15, 18, 21]
l2 = [4, 8, 12, 16, 20, 24, 28]Expected Output:
Element at odd-index positions from list one [6, 12, 18] Element at even-index positions from list two [4, 12, 20, 28] Printing Final third list [6, 12, 18, 4, 12, 20, 28]
Show Hint
Use list slicing
Show Solution
To access a range of items in a list, use the slicing operator :. With this operator, you can specify where to start the slicing, end, and specify the step.
For example, the expression list1[ start : stop : step] returns the portion of the list from index start to index stop, at a step size step.
- for 1st list: Start from the 1st index with step value 2 so it will pick elements present at index 1, 3, 5, and so on
- for 2nd list: Start from the 0th index with step value 2 so it will pick elements present at index 0, 2, 4, and so on
list1 = [3, 6, 9, 12, 15, 18, 21]
list2 = [4, 8, 12, 16, 20, 24, 28]
res = list()
odd_elements = list1[1::2]
print("Element at odd-index positions from list one")
print(odd_elements)
even_elements = list2[0::2]
print("Element at even-index positions from list two")
print(even_elements)
print("Printing Final third list")
res.extend(odd_elements)
res.extend(even_elements)
print(res)
Exercise 2: Remove and add item in a list
Write a program to remove the item present at index 4 and add it to the 2nd position and at the end of the list.
Given:
list1 = [54, 44, 27, 79, 91, 41]Expected Output:
List After removing element at index 4 [34, 54, 67, 89, 43, 94] List after Adding element at index 2 [34, 54, 11, 67, 89, 43, 94] List after Adding element at last [34, 54, 11, 67, 89, 43, 94, 11]
Show Hint
Use the list methods, pop(), insert() and append()
Show Solution
pop(index): Removes and returns the item at the given index from the list.insert(index, item): Add the item at the specified position(index) in the listappend(item): Add item at the end of the list.
sample_list = [34, 54, 67, 89, 11, 43, 94]
print("Original list ", sample_list)
element = sample_list.pop(4)
print("List After removing element at index 4 ", sample_list)
sample_list.insert(2, element)
print("List after Adding element at index 2 ", sample_list)
sample_list.append(element)
print("List after Adding element at last ", sample_list)Exercise 3: Slice list into 3 equal chunks and reverse each chunk
Given:
sample_list = [11, 45, 8, 23, 14, 12, 78, 45, 89]Expected Outcome:
Chunk 1 [11, 45, 8] After reversing it [8, 45, 11] Chunk 2 [23, 14, 12] After reversing it [12, 14, 23] Chunk 3 [78, 45, 89] After reversing it [89, 45, 78]
Show Hint
- Divide the length of a list by 3 to get the each chunk size
- Run loop three times and use the
slice()function to get the chunk and reverse it
Show Solution
- Get the length of a list using a
len()function - Divide the length by 3 to get the chunk size
- Run loop three times
- In each iteration, get a chunk using a
slice(start, end, step)function and reverse it using thereversed()function - In each iteration,
startandendvalue will change
sample_list = [11, 45, 8, 23, 14, 12, 78, 45, 89]
print("Original list ", sample_list)
length = len(sample_list)
chunk_size = int(length / 3)
start = 0
end = chunk_size
# run loop 3 times
for i in range(3):
# get indexes
indexes = slice(start, end)
# get chunk
list_chunk = sample_list[indexes]
print("Chunk ", i, list_chunk)
# reverse chunk
print("After reversing it ", list(reversed(list_chunk)))
start = end
end += chunk_size
Exercise 4: Count the occurrence of each element from a list
Write a program to iterate a given list and count the occurrence of each element and create a dictionary to show the count of each element.
Given:
sample_list = [11, 45, 8, 11, 23, 45, 23, 45, 89]Expected Output:
Printing count of each item {11: 2, 45: 3, 8: 1, 23: 2, 89: 1}
Show Solution
sample_list = [11, 45, 8, 11, 23, 45, 23, 45, 89]
print("Original list ", sample_list)
count_dict = dict()
for item in sample_list:
if item in count_dict:
count_dict[item] += 1
else:
count_dict[item] = 1
print("Printing count of each item ", count_dict)
Exercise 5: Create a Python set such that it shows the element from both lists in a pair
Given:
first_list = [2, 3, 4, 5, 6, 7, 8]
second_list = [4, 9, 16, 25, 36, 49, 64]
Expected Output:
Result is {(6, 36), (8, 64), (4, 16), (5, 25), (3, 9), (7, 49), (2, 4)}
Show Hint
Use the zip() function. This function takes two or more iterables (like list, dict, string), aggregates them in a tuple, and returns it.
Show Solution
first_list = [2, 3, 4, 5, 6, 7, 8]
print("First List ", first_list)
second_list = [4, 9, 16, 25, 36, 49, 64]
print("Second List ", second_list)
result = zip(first_list, second_list)
result_set = set(result)
print(result_set)
Exercise 6: Find the intersection (common) of two sets and remove those elements from the first set
See: Python Set
Given:
first_set = {23, 42, 65, 57, 78, 83, 29}
second_set = {57, 83, 29, 67, 73, 43, 48}
Expected Output:
Intersection is {57, 83, 29}
First Set after removing common element {65, 42, 78, 23}
Show Hint
- Use the
intersection()andremove()method of a set
Show Solution
- Get the common items using the
first_set.intersection(second_set) - Next, iterate common items using a for loop
- In each iteration, use the
remove()method of on first set and pass the current item to it.
first_set = {23, 42, 65, 57, 78, 83, 29}
second_set = {57, 83, 29, 67, 73, 43, 48}
print("First Set ", first_set)
print("Second Set ", second_set)
intersection = first_set.intersection(second_set)
print("Intersection is ", intersection)
for item in intersection:
first_set.remove(item)
print("First Set after removing common element ", first_set)
Exercise 7: Checks if one set is a subset or superset of another set. If found, delete all elements from that set
Given:
first_set = {27, 43, 34}
second_set = {34, 93, 22, 27, 43, 53, 48}Expected Output:
First set is subset of second set - True
Second set is subset of First set - False
First set is Super set of second set - False
Second set is Super set of First set - True
First Set set()
Second Set {67, 73, 43, 48, 83, 57, 29}
Show Hint
Use the below methods of a set class
issubset()issuperset()clear()
Show Solution
first_set = {57, 83, 29}
second_set = {57, 83, 29, 67, 73, 43, 48}
print("First Set ", first_set)
print("Second Set ", second_set)
print("First set is subset of second set -", first_set.issubset(second_set))
print("Second set is subset of First set - ", second_set.issubset(first_set))
print("First set is Super set of second set - ", first_set.issuperset(second_set))
print("Second set is Super set of First set - ", second_set.issuperset(first_set))
if first_set.issubset(second_set):
first_set.clear()
if second_set.issubset(first_set):
second_set.clear()
print("First Set ", first_set)
print("Second Set ", second_set)Exercise 8: Iterate a given list and check if a given element exists as a key’s value in a dictionary. If not, delete it from the list
Given:
roll_number = [47, 64, 69, 37, 76, 83, 95, 97]
sample_dict = {'Jhon':47, 'Emma':69, 'Kelly':76, 'Jason':97}Expected Outcome:
After removing unwanted elements from list [47, 69, 76, 97]
Show Solution
roll_number = [47, 64, 69, 37, 76, 83, 95, 97]
sample_dict = {'Jhon': 47, 'Emma': 69, 'Kelly': 76, 'Jason': 97}
print("List:", roll_number)
print("Dictionary:", sample_dict)
# create new list
roll_number[:] = [item for item in roll_number if item in sample_dict.values()]
print("after removing unwanted elements from list:", roll_number)
Exercise 9: Get all values from the dictionary and add them to a list but don’t add duplicates
Given:
speed = {'jan': 47, 'feb': 52, 'march': 47, 'April': 44, 'May': 52, 'June': 53, 'july': 54, 'Aug': 44, 'Sept': 54}Expected Outcome:
[47, 52, 44, 53, 54]
Show Solution
speed = {'jan': 47, 'feb': 52, 'march': 47, 'April': 44, 'May': 52, 'June': 53,
'july': 54, 'Aug': 44, 'Sept': 54}
print("Dictionary's values - ", speed.values())
speed_list = list()
# iterate dict values
for val in speed.values():
# check if value not present in a list
if val not in speed_list:
speed_list.append(val)
print("unique list", speed_list)Exercise 10: Remove duplicates from a list and create a tuple and find the minimum and maximum number
Given:
sample_list = [87, 45, 41, 65, 94, 41, 99, 94]Expected Outcome:
unique items [87, 45, 41, 65, 99] tuple (87, 45, 41, 65, 99) min: 41 max: 99
Show Solution
sample_list = [87, 52, 44, 53, 54, 87, 52, 53]
print("Original list", sample_list)
sample_list = list(set(sample_list))
print("unique list", sample_list)
t = tuple(sample_list)
print("tuple ", t)
print("Minimum number is: ", min(t))
print("Maximum number is: ", max(t))
