Converting List Of Tuples In Python To Dictionary

Imagine a social network website which allows people to specify which other people they like. We can store information about who likes who in a list of tuples, such as the one assi

Solution 1:

Use either defaultdict(list) or dict.setdefault(..., []) - there's not much difference in performance or readability, so it's really a matter of taste. I prefer using setdefault:

likes = {}
for k, v in friendface:
    likes.setdefault(k, []).append(v)

Solution 2:

Here is a solution using defaultdict:

def likes_relation(friendface):
    d = defaultdict(list)
    for k, v in friendface:
        d[k].append(v)
    return d

Result:

>>> for k,v in likes_relation(f).items():
    print (k, v)


Hera ['Aphrodite']
Apollo ['Aphrodite']
Aphrodite ['Apollo', 'Zeus', 'Athena']
Zeus ['Apollo', 'Aphrodite', 'Athena', 'Hera']
Athena ['Hera', 'Aphrodite']

Hope this helps!