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

Python Data Structure: Exercise-10 with Solution

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

Sample Solution:

Python Code:

from collections import defaultdict
class_roll = [('v', 1), ('vi', 2), ('v', 3), ('vi', 4), ('vii', 1)]
d = defaultdict(list)
for k, v in class_roll:
    d[k].append(v)
print(sorted(d.items()))

Sample Output:

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

Flowchart:

Python Code Editor:

Contribute your code and comments through Disqus.

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).