每日python（1）

原始数据是每个用户对于所看过电影的评分：

我们的用户有‘Lisa Rose‘，‘Gene Seymour‘等等，原始数据cirtics是一个字典，key为用户名，value为一个电影评分字典，该字典的key为电影名，value为评分

如何找到所有的电影的集合呢？

 1 critics = {‘Lisa Rose‘: {‘Lady in the Water‘: 2.5, ‘Snakes on a Plane‘: 3.5,
 2                          ‘Just My Luck‘: 3.0, ‘Superman Returns‘: 3.5, ‘You, Me and Dupree‘: 2.5,
 3                          ‘The Night Listener‘: 3.0},
 4            ‘Gene Seymour‘: {‘Lady in the Water‘: 3.0, ‘Snakes on a Plane‘: 3.5,
 5                             ‘Just My Luck‘: 1.5, ‘Superman Returns‘: 5.0, ‘The Night Listener‘: 3.0,
 6                             ‘You, Me and Dupree‘: 3.5},
 7            ‘Michael Phillips‘: {‘Lady in the Water‘: 2.5, ‘Snakes on a Plane‘: 3.0,
 8                                 ‘Superman Returns‘: 3.5, ‘The Night Listener‘: 4.0},
 9            ‘Claudia Puig‘: {‘Snakes on a Plane‘: 3.5, ‘Just My Luck‘: 3.0,
10                             ‘The Night Listener‘: 4.5, ‘Superman Returns‘: 4.0,
11                             ‘You, Me and Dupree‘: 2.5},
12            ‘Mick LaSalle‘: {‘Lady in the Water‘: 3.0, ‘Snakes on a Plane‘: 4.0,
13                             ‘Just My Luck‘: 2.0, ‘Superman Returns‘: 3.0, ‘The Night Listener‘: 3.0,
14                             ‘You, Me and Dupree‘: 2.0},
15            ‘Jack Matthews‘: {‘Lady in the Water‘: 3.0, ‘Snakes on a Plane‘: 4.0,
16                              ‘The Night Listener‘: 3.0, ‘Superman Returns‘: 5.0, ‘You, Me and Dupree‘: 3.5},
17            ‘Toby‘: {‘Snakes on a Plane‘: 4.5, ‘You, Me and Dupree‘: 1.0, ‘Superman Returns‘: 4.0}}
18 aa = [critics[i].keys() for i in critics]
19 print aa
20 bb = list(set(item for sublist in aa for item in sublist))
21 print bb