# pseudocode

a = [ { "id": 1, "score":200 }, { "id": 2, "score":300 }, { "id":3, "score":400 } ]

b = [ { "id": 1, "newscore":500 }, { "id": 2, "newscore":600 } ]

for update in b:
    a['score'] == update['newscore'] where a['id'] = update['id']