How to reorganize a list of tuples?

问题

Say I had a list of tuples:

[(98, 'studentA'), (97, 'studentB'), (98, 'studentC'), (95,'studentD')]

And I wanted to organize it so that the students are grouped together by the first number in the tuple, what would be the best approach?

I was thinking about creating an array of lists, in which each index of the array would be a different score (98, 97, and 95 in this example) and the students would be in the list at that index. For a much larger dataset I was considering creating a chaining hash table, but I wasn't sure what to % it to, to guarantee that two scores that aren't the same won't get hashed to the same spot.

回答1:

Why not use a dict? collections.defaultdict would work too:

d = defaultdict(list)
for score, student in l:
    d[score] += student

回答2:

Try using sorted with a key of the number

sorted(students, key=(lambda x: x[0]))

But a dictionary would be a better idea for a large dataset

来源：https://stackoverflow.com/questions/45466753/how-to-reorganize-a-list-of-tuples