01_file_owners.py

"""
10 min

Implement a group_by_owners function that:

    Accepts a dictionary containing the file owner name for each file name.
    Returns a dictionary containing a list of file names for each owner name, in any order.

For example, for dictionary {'Input.txt': 'Randy', 'Code.py': 'Stan', 'Output.txt': 'Randy'}
the group_by_owners function should return {'Randy': ['Input.txt', 'Output.txt'], 'Stan': ['Code.py']}.


    def group_by_owners(files):
        return None

    files = {
        'Input.txt': 'Randy',
        'Code.py': 'Stan',
        'Output.txt': 'Randy'
    }
    print(group_by_owners(files))
"""

from collections import defaultdict


def group_by_owners(files):
    owners = defaultdict(list)
    for file, owner in files.items():
        owners[owner].append(file)
    return owners


files = {
    'Input.txt': 'Randy',
    'Code.py': 'Stan',
    'Output.txt': 'Randy'
}
print(group_by_owners(files))