w3resource

Python: Group a sequence of key-value pairs into a dictionary of lists

Python Collections: Exercise-35 with Solution

Write a Python program to group a sequence of key-value pairs into a dictionary of lists.

Sample Solution:

Python Code:

# Import the defaultdict class from the collections module
from collections import defaultdict

# Create a list 'class_roll' containing tuples with class names and roll numbers
class_roll = [('v', 1), ('vi', 2), ('v', 3), ('vi', 4), ('vii', 1)]

# Create a defaultdict 'd' to store lists of roll numbers for each class
d = defaultdict(list)

# Loop through the tuples in 'class_roll'
for k, v in class_roll:
    # Append the roll number 'v' to the list associated with class 'k' in 'd'
    d[k].append(v)

# Sort the items (key-value pairs) in 'd' and print the result
print(sorted(d.items())) 

Sample Output:

[('v', [1, 3]), ('vi', [2, 4]), ('vii', [1])]

Flowchart:

Flowchart - Python Collections: Group a sequence of key-value pairs into a dictionary of lists.

Python Code Editor:

Previous: Write a Python program to create an instance of an OrderedDict using a given dictionary. Sort the dictionary during the creation and print the members of the dictionary in reverse order.
Next: Write a Python program to compare two unordered lists (not sets).

What is the difficulty level of this exercise?

Test your Programming skills with w3resource's quiz.



Become a Patron!

Follow us on Facebook and Twitter for latest update.

It will be nice if you may share this link in any developer community or anywhere else, from where other developers may find this content. Thanks.

https://198.211.115.131/python-exercises/collections/python-collections-exercise-35.php