Python Data Types: Dictionary - Exercises, Practice, Solution
This resource offers a total of 450 Python Dictionary problems for practice. It includes 90 main exercises, each accompanied by solutions, detailed explanations, and four related problems.
[An Editor is available at the bottom of the page to write and execute the scripts.]
Python dictionary is a container of the unordered set of objects like lists. The objects are surrounded by curly braces { }. The items in a dictionary are a comma-separated list of key:value pairs where keys and values are Python data type.
You may read our Python dictionary tutorial before solving the following exercises.
1. Sort Dictionary by Value
Write a Python script to sort (ascending and descending) a dictionary by value.
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2. Add Key to Dictionary
Write a Python script to add a key to a dictionary.
Sample Dictionary : {0: 10, 1: 20}
Expected Result : {0: 10, 1: 20, 2: 30}
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3. Concatenate Dictionaries
Write a Python script to concatenate the following dictionaries to create a new one.
Sample Dictionary :
dic1={1:10, 2:20}
dic2={3:30, 4:40}
dic3={5:50,6:60}
Expected Result : {1: 10, 2: 20, 3: 30, 4: 40, 5: 50, 6: 60}
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4. Check Key Existence in Dictionary
Write a Python script to check whether a given key already exists in a dictionary.
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5. Iterate Over Dictionary Using For Loops
Write a Python program to iterate over dictionaries using for loops.
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6. Generate Dictionary of Numbers and Their Squares
Write a Python script to generate and print a dictionary that contains a number (between 1 and n) in the form (x, x*x).
Sample Dictionary ( n = 5) :
Expected Output : {1: 1, 2: 4, 3: 9, 4: 16, 5: 25}
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7. Dictionary with Keys 1 to 15 and Their Squares
Write a Python script to print a dictionary where the keys are numbers between 1 and 15 (both included) and the values are the square of the keys.
Sample Dictionary
{1: 1, 2: 4, 3: 9, 4: 16, 5: 25, 6: 36, 7: 49, 8: 64, 9: 81, 10: 100, 11: 121, 12: 144, 13: 169, 14: 196, 15: 225}
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8. Merge Two Python Dictionaries
Write a Python script to merge two Python dictionaries.
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9. Iterate Over Dictionaries (Alternative)
Write a Python program to iterate over dictionaries using for loops.
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10. Sum All Items in a Dictionary
Write a Python program to sum all the items in a dictionary.
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11. Multiply All Items in a Dictionary
Write a Python program to multiply all the items in a dictionary.
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12. Remove a Key from a Dictionary
Write a Python program to remove a key from a dictionary.
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13. Map Two Lists into a Dictionary
Write a Python program to map two lists into a dictionary.
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14. Sort Dictionary by Key
Write a Python program to sort a given dictionary by key.
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15. Get Maximum and Minimum Values of a Dictionary
Write a Python program to get the maximum and minimum values of a dictionary.
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16. Get Dictionary from an Object's Fields
Write a Python program to get a dictionary from an object's fields.
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17. Remove Duplicates from the Dictionary
Write a Python program to remove duplicates from the dictionary.
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18. Check if a Dictionary is Empty
Write a Python program to check if a dictionary is empty or not.
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19. Combine Two Dictionaries by Adding Values
Write a Python program to combine two dictionary by adding values for common keys.
d1 = {'a': 100, 'b': 200, 'c':300}
d2 = {'a': 300, 'b': 200, 'd':400}
Sample output: Counter({'a': 400, 'b': 400, 'd': 400, 'c': 300})
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20. Print All Distinct Values in a Dictionary
Write a Python program to print all distinct values in a dictionary.
Sample Data : [{"V":"S001"}, {"V": "S002"}, {"VI": "S001"}, {"VI": "S005"}, {"VII":"S005"}, {"V":"S009"},{"VIII":"S007"}]
Expected Output : Unique Values: {'S005', 'S002', 'S007', 'S001', 'S009'}
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21. Create Combinations of Letters from Dictionary Keys
Write a Python program to create and display all combinations of letters, selecting each letter from a different key in a dictionary.
Sample data : {'1':['a','b'], '2':['c','d']}
Expected Output:
ac
ad
bc
bd
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22. Find Highest 3 Values of Corresponding Keys in a Dictionary
Write a Python program to find the highest 3 values of corresponding keys in a dictionary.
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23. Combine Values in a List of Dictionaries
Write a Python program to combine values in a list of dictionaries.
Sample data: [{'item': 'item1', 'amount': 400}, {'item': 'item2', 'amount': 300}, {'item': 'item1', 'amount': 750}]
Expected Output: Counter({'item1': 1150, 'item2': 300})
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24. Create Dictionary from a String (Letter Frequency)
Write a Python program to create a dictionary from a string.
Note: Track the count of the letters from the string.
Sample string : 'w3resource'
Expected output: {'w': 1, '3': 1, 'r': 2, 'e': 2, 's': 1, 'o': 1, 'u': 1, 'c': 1}
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25. Print Dictionary in Table Format
Write a Python program to print a dictionary in table format.
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26. Count Values Associated with a Key in a Dictionary
Write a Python program to count the values associated with a key in a dictionary.
Expected Output:
6
2
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27. Convert List into Nested Dictionary of Keys
Write a Python program to convert a list into a nested dictionary of keys.
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28. Sort a List Alphabetically in a Dictionary
Write a Python program to sort a list alphabetically in a dictionary.
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29. Remove Spaces from Dictionary Keys
Write a Python program to remove spaces from dictionary keys.
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30. Get Top Three Items in a Shop
Write a Python program to get the top three items in a shop.
Sample data: {'item1': 45.50, 'item2':35, 'item3': 41.30, 'item4':55, 'item5': 24}
Expected Output:
item4 55
item1 45.5
item3 41.3
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31. Get Key, Value, and Item in a Dictionary
Write a Python program to get the key, value and item in a dictionary.
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32. Print Dictionary Line by Line
Write a Python program to print a dictionary line by line.
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33. Check if Multiple Keys Exist in a Dictionary
Write a Python program to check if multiple keys exist in a dictionary.
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34. Count Number of Items in Dictionary Value That is a List
Write a Python program to count the number of items in a dictionary value that is a list.
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35. Sort Counter by Value
Write a Python program to sort Counter by value.
Sample data : {'Math':81, 'Physics':83, 'Chemistry':87}
Expected data: [('Chemistry', 87), ('Physics', 83), ('Math', 81)]
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36. Create Dictionary from Two Lists Without Losing Duplicates
Write a Python program to create a dictionary from two lists without losing duplicate values.
Sample lists: ['Class-V', 'Class-VI', 'Class-VII', 'Class-VIII'], [1, 2, 2, 3]
Expected Output: defaultdict(<class 'set'>, {'Class-V': {1}, 'Class-VI': {2}, 'Class-VII': {2}, 'Class-VIII': {3}})
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37. Replace Dictionary Values with Their Sums
Write a Python program to replace dictionary values with their sums.
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38. Match Key Values in Two Dictionaries
Write a Python program to match key values in two dictionaries.
Sample dictionary: {'key1': 1, 'key2': 3, 'key3': 2}, {'key1': 1, 'key2': 2}
Expected output: key1: 1 is present in both x and y
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39. Store Dictionary Data in a JSON File
Write a Python program to store dictionary data in a JSON file.
Original dictionary:
{'students': [{'firstName': 'Nikki', 'lastName': 'Roysden'}, {'firstName': 'Mervin', 'lastName': 'Friedland'}, {'firstName': 'Aron ', 'lastName': 'Wilkins'}], 'teachers': [{'firstName': 'Amberly', 'lastName': 'Calico'}, {'firstName': 'Regine', 'lastName': 'Agtarap'}]}
<class 'dict'>
Json file to dictionary:
{'students': [{'firstName': 'Nikki', 'lastName': 'Roysden'}, {'firstName': 'Mervin', 'lastName': 'Friedland'}, {'firstName': 'Aron ', 'lastName': 'Wilkins'}], 'teachers': [{'firstName': 'Amberly', 'lastName': 'Calico'}, {'firstName': 'Regine', 'lastName': 'Agtarap'}]}
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40. Create Dictionary with Keys 'x', 'y', 'z' and List Values
Write a Python program to create a dictionary of keys x, y, and z where each key has as value a list from 11-20, 21-30, and 31-40 respectively. Access the fifth value of each key from the dictionary.
{'x': [11, 12, 13, 14, 15, 16, 17, 18, 19],
'y': [21, 22, 23, 24, 25, 26, 27, 28, 29],
'z': [31, 32, 33, 34, 35, 36, 37, 38, 39]}
15
25
35
x has value [11, 12, 13, 14, 15, 16, 17, 18, 19]
y has value [21, 22, 23, 24, 25, 26, 27, 28, 29]
z has value [31, 32, 33, 34, 35, 36, 37, 38, 39]
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41. Drop Empty Items from Dictionary
Write a Python program to drop empty items from a given dictionary.
Original Dictionary:
{'c1': 'Red', 'c2': 'Green', 'c3': None}
New Dictionary after dropping empty items:
{'c1': 'Red', 'c2': 'Green'}
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42. Filter Dictionary Based on Values
Write a Python program to filter a dictionary based on values.
Original Dictionary:
{'Cierra Vega': 175, 'Alden Cantrell': 180, 'Kierra Gentry': 165, 'Pierre Cox': 190}
Marks greater than 170:
{'Cierra Vega': 175, 'Alden Cantrell': 180, 'Pierre Cox': 190}
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43. Convert Multiple Lists to a Nested Dictionary
Write a Python program to convert more than one list to a nested dictionary.
Original strings:
['S001', 'S002', 'S003', 'S004']
['Adina Park', 'Leyton Marsh', 'Duncan Boyle', 'Saim Richards']
[85, 98, 89, 92]
Nested dictionary:
[{'S001': {'Adina Park': 85}}, {'S002': {'Leyton Marsh': 98}}, {'S003': {'Duncan Boyle': 89}}, {'S004': {'Saim Richards': 92}}]
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44. Filter Students by Height and Weight
Write a Python program to filter the height and width of students, which are stored in a dictionary.
Original Dictionary:
{'Cierra Vega': (6.2, 70), 'Alden Cantrell': (5.9, 65), 'Kierra Gentry': (6.0, 68), 'Pierre Cox': (5.8, 66)}
Height > 6ft and Weight> 70kg:
{'Cierra Vega': (6.2, 70)}
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45. Verify All Dictionary Values are the Same
Write a Python program to verify that all values in a dictionary are the same.
Original Dictionary:
{'Cierra Vega': 12, 'Alden Cantrell': 12, 'Kierra Gentry': 12, 'Pierre Cox': 12}
Check all are 12 in the dictionary.
True
Check all are 10 in the dictionary.
False
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46. Group Key-Value Pairs into Dictionary of Lists
Write a Python program to create a dictionary grouping a sequence of key-value pairs into a dictionary of lists.
Original list:
[('yellow', 1), ('blue', 2), ('yellow', 3), ('blue', 4), ('red', 1)]
Grouping a sequence of key-value pairs into a dictionary of lists:
{'yellow': [1, 3], 'blue': [2, 4], 'red': [1]}
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47. Split Dictionary of Lists into List of Dictionaries
Write a Python program to split a given dictionary of lists into lists of dictionaries.
Original dictionary of lists:
{'Science': [88, 89, 62, 95], 'Language': [77, 78, 84, 80]}
Split said dictionary of lists into list of dictionaries:
[{'Science': 88, 'Language': 77}, {'Science': 89, 'Language': 78}, {'Science': 62, 'Language': 84}, {'Science': 95, 'Language': 80}]
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48. Remove Specified Dictionary from a List
Write a Python program to remove a specified dictionary from a given list.
Original list of dictionary:
[{'id': '#FF0000', 'color': 'Red'}, {'id': '#800000', 'color': 'Maroon'}, {'id': '#FFFF00', 'color': 'Yellow'}, {'id': '#808000', 'color': 'Olive'}]
Remove id #FF0000 from the said list of dictionary:
[{'id': '#800000', 'color': 'Maroon'}, {'id': '#FFFF00', 'color': 'Yellow'}, {'id': '#808000', 'color': 'Olive'}]
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49. Convert String Values in Dictionary to Numeric Types
Write a Python program to convert string values of a given dictionary into integer/float datatypes.
Original list:
[{'x': '10', 'y': '20', 'z': '30'}, {'p': '40', 'q': '50', 'r': '60'}]
String values of a given dictionary, into integer types:
[{'x': 10, 'y': 20, 'z': 30}, {'p': 40, 'q': 50, 'r': 60}]
Original list:
[{'x': '10.12', 'y': '20.23', 'z': '30'}, {'p': '40.00', 'q': '50.19', 'r': '60.99'}]
String values of a given dictionary, into float types:
[{'x': 10.12, 'y': 20.23, 'z': 30.0}, {'p': 40.0, 'q': 50.19, 'r': 60.99}]
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50. Clear List Values in a Dictionary
A Python dictionary contains List as a value. Write a Python program to clear the list values in the said dictionary.
Original Dictionary:
{'C1': [10, 20, 30], 'C2': [20, 30, 40], 'C3': [12, 34]}
Clear the list values in the said dictionary:
{'C1': [], 'C2': [], 'C3': []}
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51. Update List Values in a Dictionary
A Python Dictionary contains List as a value. Write a Python program to update the list values in the said dictionary.
Original Dictionary:
{'Math': [88, 89, 90], 'Physics': [92, 94, 89], 'Chemistry': [90, 87, 93]}
Update the list values of the said dictionary:
{'Math': [89, 90, 91], 'Physics': [90, 92, 87], 'Chemistry': [90, 87, 93]}
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52. Extract List of Values from List of Dictionaries
Write a Python program to extract a list of values from a given list of dictionaries.
Original Dictionary:
[{'Math': 90, 'Science': 92}, {'Math': 89, 'Science': 94}, {'Math': 92, 'Science': 88}]
Extract a list of values from said list of dictionaries where subject = Science
[92, 94, 88]
Original Dictionary:
[{'Math': 90, 'Science': 92}, {'Math': 89, 'Science': 94}, {'Math': 92, 'Science': 88}]
Extract a list of values from said list of dictionaries where subject = Math
[90, 89, 92]
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53. Find Length of a Dictionary
Write a Python program to find the length of a dictionary of values.
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54. Get Depth of a Dictionary
Write a Python program to get the depth of a dictionary.
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55. Access Dictionary Key's Element by Index
Write a Python program to access dictionary key's element by index.
Expected Output:
physics
math
chemistry
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56. Convert Dictionary into a List of Lists
Write a Python program to convert a dictionary into a list of lists.
Original Dictionary:
{1: 'red', 2: 'green', 3: 'black', 4: 'white', 5: 'black'}
Convert the said dictionary into a list of lists:
[[1, 'red'], [2, 'green'], [3, 'black'], [4, 'white'], [5, 'black']]
Original Dictionary:
{'1': 'Austin Little', '2': 'Natasha Howard', '3': 'Alfred Mullins', '4': 'Jamie Rowe'}
Convert the said dictionary into a list of lists:
[['1', 'Austin Little'], ['2', 'Natasha Howard'], ['3', 'Alfred Mullins'], ['4', 'Jamie Rowe']]
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57. Filter Even Numbers from Dictionary Values
Write a Python program to filter even numbers from a dictionary of values.
Original Dictionary:
{'V': [1, 4, 6, 10], 'VI': [1, 4, 12], 'VII': [1, 3, 8]}
Filter even numbers from said dictionary values:
{'V': [4, 6, 10], 'VI': [4, 12], 'VII': [8]}
Original Dictionary:
{'V': [1, 3, 5], 'VI': [1, 5], 'VII': [2, 7, 9]}
Filter even numbers from said dictionary values:
{'V': [], 'VI': [], 'VII': [2]}
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58. Get All Combinations of Key-Value Pairs in a Dictionary
Write a Python program to get all combinations of key-value pairs in a given dictionary.
Original Dictionary:
{'V': [1, 4, 6, 10], 'VI': [1, 4, 12], 'VII': [1, 3, 8]}
Combinations of key-value pairs of the said dictionary:
[{'V': [1, 4, 6, 10], 'VI': [1, 4, 12]}, {'V': [1, 4, 6, 10], 'VII': [1, 3, 8]}, {'VI': [1, 4, 12], 'VII': [1, 3, 8]}]
Original Dictionary:
{'V': [1, 3, 5], 'VI': [1, 5]}
Combinations of key-value pairs of the said dictionary:
[{'V': [1, 3, 5], 'VI': [1, 5]}]
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59. Find Specified Number of Maximum Values in a Dictionary
Write a Python program to find the specified number of maximum values in a given dictionary.
Original Dictionary:
{'a': 5, 'b': 14, 'c': 32, 'd': 35, 'e': 24, 'f': 100, 'g': 57, 'h': 8, 'i': 100}
1 maximum value(s) in the said dictionary:
['f']
2 maximum value(s) in the said dictionary:
['f', 'i']
5 maximum value(s) in the said dictionary:
['f', 'i', 'g', 'd', 'c']
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60. Find the Shortest List of Values for the Keys in a Dictionary
Write a Python program to find the shortest list of values for the keys in a given dictionary.
Original Dictionary:
{'V': [10, 12], 'VI': [10], 'VII': [10, 20, 30, 40], 'VIII': [20], 'IX': [10, 30, 50, 70], 'X': [80]}
Shortest list of values with the keys of the said dictionary:
['VI', 'VIII', 'X']
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61. Count Frequency of a Dictionary's Values
Write a Python program to count the frequency of a dictionary.
Original Dictionary:
{'V': 10, 'VI': 10, 'VII': 40, 'VIII': 20, 'IX': 70, 'X': 80, 'XI': 40, 'XII': 20}
Count the frequency of the said dictionary:
Counter({10: 2, 40: 2, 20: 2, 70: 1, 80: 1})
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62. Extract Values from Dictionary and Create a List of Lists
Write a Python program to extract values from a given dictionary and create a list of lists from those values.
Original Dictionary:
[{'student_id': 1, 'name': 'Jean Castro', 'class': 'V'}, {'student_id': 2, 'name': 'Lula Powell', 'class': 'V'}, {'student_id': 3, 'name': 'Brian Howell', 'class': 'VI'}, {'student_id': 4, 'name': 'Lynne Foster', 'class': 'VI'}, {'student_id': 5, 'name': 'Zachary Simon', 'class': 'VII'}]
Extract values from the said dictionarie and create a list of lists using those values:
[[1, 'Jean Castro', 'V'], [2, 'Lula Powell', 'V'], [3, 'Brian Howell', 'VI'], [4, 'Lynne Foster', 'VI'], [5, 'Zachary Simon', 'VII']]
[[1, 'Jean Castro'], [2, 'Lula Powell'], [3, 'Brian Howell'], [4, 'Lynne Foster'], [5, 'Zachary Simon']]
[['Jean Castro', 'V'], ['Lula Powell', 'V'], ['Brian Howell', 'VI'], ['Lynne Foster', 'VI'], ['Zachary Simon', 'VII']]
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63. Convert List of Lists to a Dictionary
Write a Python program to convert a given list of lists to a dictionary.
Original list of lists:
[[1, 'Jean Castro', 'V'], [2, 'Lula Powell', 'V'], [3, 'Brian Howell', 'VI'], [4, 'Lynne Foster', 'VI'], [5, 'Zachary Simon', 'VII']]
Convert the said list of lists to a dictionary:
{1: ['Jean Castro', 'V'], 2: ['Lula Powell', 'V'], 3: ['Brian Howell', 'VI'], 4: ['Lynne Foster', 'VI'], 5: ['Zachary Simon', 'VII']}
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64. Create Key-Value List Pairings within a Dictionary
Write a Python program that creates key-value list pairings within a dictionary.
Original dictionary:
{1: ['Jean Castro'], 2: ['Lula Powell'], 3: ['Brian Howell'], 4: ['Lynne Foster'], 5: ['Zachary Simon']}
A key-value list pairings of the said dictionary:
[{1: 'Jean Castro', 2: 'Lula Powell', 3: 'Brian Howell', 4: 'Lynne Foster', 5: 'Zachary Simon'}]
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65. Total Length of All Values in Dictionary (String Values)
Write a Python program to get the total length of all values in a given dictionary with string values.
Original dictionary:
{'#FF0000': 'Red', '#800000': 'Maroon', '#FFFF00': 'Yellow', '#808000': 'Olive'}
Total length of all values of the said dictionary with string values:
20
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66. Check if Specific Key and Value Exist in Dictionary
Write a Python program to check if a specific key and a value exist in a dictionary.
Original dictionary:
[{'student_id': 1, 'name': 'Jean Castro', 'class': 'V'}, {'student_id': 2, 'name': 'Lula Powell', 'class': 'V'}, {'student_id': 3, 'name': 'Brian Howell', 'class': 'VI'}, {'student_id': 4, 'name': 'Lynne Foster', 'class': 'VI'}, {'student_id': 5, 'name': 'Zachary Simon', 'class': 'VII'}]
Check if a specific Key and a value exist in the said dictionary:
True
True
True
False
False
False
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67. Invert Dictionary with Non-Unique Values
Write a Python program to invert a given dictionary with non-unique hashable values.
Sample Output:
{8: ['Ora Mckinney', 'Mathew Gilbert'], 7: ['Theodore Hollandl', 'Mae Fleming', 'Ivan Little']}
Click me to see the sample solution
68. Combine Dictionaries Creating List of Values per Key
Write a Python program to combine two or more dictionaries, creating a list of values for each key.
Original dictionaries:
{'w': 50, 'x': 100, 'y': 'Green', 'z': 400}
{'x': 300, 'y': 'Red', 'z': 600}
Combined dictionaries, creating a list of values for each key:
{'w': [50], 'x': [100, 300], 'y': ['Green', 'Red'], 'z': [400, 600]}
Click me to see the sample solution
69. Group Elements of a List Based on a Function
Write a Python program to group the elements of a given list based on the given function.
Original list & function:
[7, 23, 3.2, 3.3, 8.4] Function name: floor:
Group the elements of the said list based on the given function:
{7: [7], 23: [23], 3: [3.2, 3.3], 8: [8.4]}
Original list & function:
['Red', 'Green', 'Black', 'White', 'Pink'] Function name: len:
Group the elements of the said list based on the given function:
{3: ['Red'], 5: ['Green', 'Black', 'White'], 4: ['Pink']}
Click me to see the sample solution
70. Map List Values to Dictionary Using a Function
Write a Python program to map the values of a given list to a dictionary using a function, where the key-value pairs consist of the original value as the key and the result of the function as the value.
Sample Output:
{1: 1, 2: 4, 3: 9, 4: 16}
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71. Retrieve Nested Value by Selector List
Write a Python program to retrieve the value of the nested key indicated by the given selector list from a dictionary or list.
Sample Output:
Russell
2
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72. Invert Dictionary with Unique Values
Write a Python program to invert a dictionary with unique hashable values.
Sample Output:
{10: 'Theodore', 11: 'Mathew', 9: 'Roxanne'}
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73. Extract List of Values from List of Dictionaries
Write a Python program to convert a list of dictionaries into a list of values corresponding to the specified key.
Original list of dictionaries:
[{'name': 'Theodore', 'age': 18}, {'name': 'Mathew', 'age': 22}, {'name': 'Roxanne', 'age': 20}, {'name': 'David', 'age': 18}]
Convert a list of dictionaries into a list of values corresponding to the specified key:
[18, 22, 20, 18]
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74. Create Dictionary with Same Keys and Function-Transformed Values
Write a Python program to create a dictionary with the same keys as the given dictionary and values generated by running the given function for each value.
Original dictionary elements:
{'Theodore': {'user': 'Theodore', 'age': 45}, 'Roxanne': {'user': 'Roxanne', 'age': 15}, 'Mathew': {'user': 'Mathew', 'age': 21}}
Dictionary with the same keys:
{'Theodore': 45, 'Roxanne': 15, 'Mathew': 21}
Click me to see the sample solution
75. Find All Keys with a Given Value
Write a Python program to find all keys in a dictionary that have the given value.
Original dictionary elements:
{'Theodore': 19, 'Roxanne': 20, 'Mathew': 21, 'Betty': 20}
Find all keys in the said dictionary that have the specified value:
['Roxanne', 'Betty']
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76. Combine Two Lists into a Dictionary
Write a Python program to combine two lists into a dictionary. The elements of the first one serve as keys and the elements of the second one serve as values. Each item in the first list must be unique and hashable.
Original lists:
['a', 'b', 'c', 'd', 'e', 'f']
[1, 2, 3, 4, 5]
Combine the values of the said two lists into a dictionary:
{'a': 1, 'b': 2, 'c': 3, 'd': 4, 'e': 5}
Click me to see the sample solution
77. Transform Dictionary into List of Tuples
Write a Python program to transform a dictionary into a list of tuples.
Original Dictionary:
{'Red': 1, 'Green': 3, 'White': 5, 'Black': 2, 'Pink': 4}
Convert the said dictionary to a list of tuples:
[('Red', 1), ('Green', 3), ('White', 5), ('Black', 2), ('Pink', 4)]
Click me to see the sample solution
78. Create Flat List of All Keys in a Dictionary
Write a Python program to create a flat list of all the keys in a flat dictionary.
Original dictionary elements:
{'Theodore': 19, 'Roxanne': 20, 'Mathew': 21, 'Betty': 20}
Create a flat list of all the keys of the said flat dictionary:
['Theodore', 'Roxanne', 'Mathew', 'Betty']
Click me to see the sample solution
79. Create Flat List of All Values in a Dictionary
Write a Python program to create a flat list of all the values in a flat dictionary.
Original dictionary elements:
{'Theodore': 19, 'Roxanne': 20, 'Mathew': 21, 'Betty': 20}
Create a flat list of all the values of the said flat dictionary:
[19, 20, 21, 20]
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80. Find Key of Maximum Value in a Dictionary
Write a Python program to find the key of the maximum value in a dictionary.
Original dictionary elements:
{'Theodore': 19, 'Roxanne': 22, 'Mathew': 21, 'Betty': 20}
Finds the key of the maximum and minimum value of the said dictionary:
('Roxanne', 'Theodore')
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81. Nested Dictionary Manipulation
Write a Python function that flattens a nested dictionary into a single-level dictionary. The keys in the flattened dictionary should be tuples representing the path to each value.
Input: {'a': 1, 'b': {'c': 2, 'd': {'e': 3}}, 'f': 4}
Output: {('a',): 1, ('b', 'c'): 2, ('b', 'd', 'e'): 3, ('f',): 4}
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82. Dictionary-based Memoization
Write a Python program to implement a memoization decorator that caches function results based on arguments. The decorator should handle any function with any number of positional and keyword arguments. Ensure that your implementation correctly handles unhashable arguments (like lists or dictionaries).
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83. Custom Dictionary with Default Factory
Write a Python program to create a custom dictionary class that allows for nested dictionary creation on the fly, similar to collections.defaultdict but with unlimited nesting depth.
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84. Dictionary Transformation Pipeline
Write a Python function that takes a list of dictionaries and a series of transformation functions, then applies each transformation in sequence to the dictionary list.
Each transformation function should take a list of dictionaries and return a modified list.
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85. Dictionary-based Graph Algorithms
Write a Python program to implement a graph using dictionaries and write functions for:
- Finding the shortest path between two nodes (Dijkstra's algorithm)
- Detecting cycles in the graph
- Performing a topological sort (if the graph is a DAG)
The graph should be represented as a dictionary where keys are nodes and values are dictionaries mapping neighboring nodes to edge weights.
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86. Dictionary Merging with Custom Conflict Resolution
Write a Python function that merges multiple dictionaries with a custom conflict resolution strategy. The function should take any number of dictionaries and a conflict resolution function. The conflict resolution function should take the key and all conflicting values and return the resolved value.
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87. Bidirectional Dictionary
Write a Python program to implement a bidirectional dictionary (BiDict) class that maintains one-to-one mappings and allows lookup in both directions with equal efficiency. Ensure that when a key-value pair is added, any existing entries with the same key or value are removed.
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88. Dictionary-based LRU Cache
Write a Python program to implement an LRU (Least Recently Used) cache using dictionaries. The cache should have a fixed capacity and remove the least recently used items when full. Implement get and put methods with O(1) time complexity.
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89. Dictionary Serialization with Circular References
Create Python functions to serialize and deserialize dictionaries that may contain circular references. The serialized format should be a string that can be evaluated back into the original structure.
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90. Dictionary-based Expression Evaluator
Write a Python function that evaluates mathematical expressions represented as dictionaries. The expression dictionary should support basic operations (+, -, *, /), variables, and nested expressions.
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