How to give points for each indices of list

Question

def voting_borda(rank_ballots):
    \'\'\'(list of list of str) -> tuple of (str, list of int)

The parameter is a list of 4-element lists that repre

Answer 1

I found your voting simulation assignment online and added a few of the constants from it here to simplify the code for solving the problem a little (although it may not look like it with their definitions at the beginning).

The first element of the tuple returned is not exactly in the requested format -- it's a list rather than a single value -- to deal with the quite real possibility of tie votes, as illustrated with the sample data values used below for rank_ballots. Even if there wasn't a tie, the element is return is a singleton list -- which actually is usually easier to deal with than having it vary depending on there's more than one or not.

PARTY_NAMES = ['NDP', 'GREEN', 'LIBERAL', 'CPC']
NAME_TO_INDEX = {party:PARTY_NAMES.index(party) for party in PARTY_NAMES}
INDEX_TO_NAME = {PARTY_NAMES.index(party):party for party in PARTY_NAMES}

def voting_borda(rank_ballots):
    results = [0 for _ in PARTY_NAMES]
    MAX_POINTS = len(PARTY_NAMES)-1
    for ballot in rank_ballots:
        for i,party in enumerate(ballot):
            results[NAME_TO_INDEX[party]] += MAX_POINTS-i

    highest_rank = max(results)
    winners = [INDEX_TO_NAME[i] for i,total in enumerate(results) if total == highest_rank]
    return winners, results

rank_ballots = [['GREEN','NDP', 'LIBERAL', 'CPC'],
                ['GREEN','CPC','LIBERAL','NDP'],
                ['LIBERAL', 'GREEN', 'NDP', 'CPC'],
                ['LIBERAL','NDP', 'CPC', 'GREEN'],]

print(voting_borda(rank_ballots))

Output:

(['GREEN', 'LIBERAL'], [5, 8, 8, 3])