使用索引运算符时Python字典读取错误

最初，我尝试将数据集读入字典

with open("msong.csv") as f:
reader = csv.DictReader(f)
data = [r for r in reader]

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字典包含如下数据：

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我正在使用该功能根据用户喜好推荐歌曲

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在输入时，我得到了一个错误

recommend(data[0][user_id],4,euclidean_similarity)

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错误：推荐（数据[0][user\u id]，4，欧几里德相似性）

数据[0][user\u id]

您使用的不是

'user\u id'

字符串作为键，而是

user\u id

变量，如果我正确理解您的意图，该变量可能未设置

def recommend(person, bound, similarity=pearson_similarity):
    scores = [(similarity(person, other), other) for other in data if other != person]

    scores.sort()
    scores.reverse()
    scores = scores[0:bound]

    print (scores)

    recomms = {}

    for sim, other in scores:
        ranked = data[other]

        for itm in ranked:
            if itm not in data[person]:
                weight = sim * ranked[itm]

                if itm in recomms:
                    s, weights = recomms[itm]
                    recomms[itm] = (s + sim, weights + [weight])
                else:
                    recomms[itm] = (sim, [weight])

    for r in recomms:
        sim, item = recomms[r]
        recomms[r] = sum(item) / sim

    return recomms

recommend(data[0][user_id],4,euclidean_similarity)