"從現有的熊貓中創建一個新的df？"

Question

我正在做一個關於電影數據的項目。
示例數據集如下所示：

列類型有 21 個唯一值。

我想創建一個新表\/數據框，以便該表包含每個用戶的每種類型的平均評分，例如

我使用以下代碼獲得了流派列表：

def split(sent):
    return (sent.split())

new_genres=set()

for i in range(len(genres)):
    a=split(genres[i])
    for g in a:
        new_genres.add(g)

new_genres

Answer 1

設置：

In [905]: df = pd.DataFrame({'userID':[1,2,3,3,2], 'id':[110, 147, 858, 1246, 1968], 'rating':[1.0, 4.5, 5.0, 5.0, 4.0], 'genres':['Drama Mystery Romance', 'Drama', 'Comedy Drama Romance', 'Drama', 'Drama Comedy Romance']}
     ...: )

In [906]: df
Out[906]: 
   userID    id  rating                 genres
0       1   110     1.0  Drama Mystery Romance
1       2   147     4.5                  Drama
2       3   858     5.0   Comedy Drama Romance
3       3  1246     5.0                  Drama
4       2  1968     4.0   Drama Comedy Romance

Answer 2

我們可以首先使用assign<\/code><\/a>方法來獲取行中的每個genre<\/code> ，如下所示：

>>> df = df.assign(genre=df['genres'].str.split(' ')).explode('genre')
>>> df
    userId  id      rating  genres                  genre
0   1       110     1.0     Drama Mystery Romance   Drama
0   1       110     1.0     Drama Mystery Romance   Mystery
0   1       110     1.0     Drama Mystery Romance   Romance
1   1       147     4.5     Drama                   Drama
2   1       858     5.0     Comedy Drama Romance    Comedy
2   1       858     5.0     Comedy Drama Romance    Drama
2   1       858     5.0     Comedy Drama Romance    Romance
3   1       1246    5.0     Drama                   Drama
4   1       1968    4.0     Drama Comedy Romance    Drama
4   1       1968    4.0     Drama Comedy Romance    Comedy
4   1       1968    4.0     Drama Comedy Romance    Romance
5   270896  48780   5.0     Forein                  Forein
6   270896  49530   4.0     Action Thriller Scifi   Action
6   270896  49530   4.0     Action Thriller Scifi   Thriller
6   270896  49530   4.0     Action Thriller Scifi   Scifi
7   270896  54001   4.0     Drama                   Drama
8   270896  54503   4.0     Action Forein           Action
8   270896  54503   4.0     Action Forein           Forein
9   270896  58559   5.0     Drama                   Drama