python3:未能加载MovieLens数据集: KeyError：'1‘

Question

我读过Programming.Collective.Intelligence一书中的例子，不知道为什么会有keyError .

u.item

movie_id | title | ...

1|Toy Story (1995)|...
2|GoldenEye (1995)|...
...

u.data

user movieid rating timestamp
196 242 3   881250949
186 302 3   891717742
...

代码

def loadMovieLens(path='E:/project/datamining/collective/chapter2/ml-100k'):
  # Get movie titles
  movies = {}
  for line in open(path+'/u.item', encoding='utf-8'):
      (id, title) = line.split('|')[0:2]
      movies[id] = title
  # load data

  prefs = {}
  for line in open(path+'/u.data',encoding='utf-8'):
      (user,movieid,rating,ts)=line.split('\t')
      prefs.setdefault(user,{})
      prefs[user][movies[movieid]] = float(rating)
  return prefs
prefs = loadMovieLens()

Traceback (most recent call last):
File "E:\project\datamining\collective\chapter2\recommendations.py", line 181, in <module>
  prefs = loadMovieLens()
File "E:\project\datamining\collective\chapter2\recommendations.py", line 179, in loadMovieLens
  prefs[user][movies[movieid]] = rating
KeyError: '1'

Answer 1

尝试错误处理。类似于：

errors = 0
    for line in open(path + '/ratings.txt'):
        try:
            (user, movieid, rating, ts) = line.split('\t')
            prefs.setdefault(user, {})
            prefs[user][movies[movieid]] = float(rating)
        except KeyError:
            errors+=1

    return prefs