熊貓groupby，pivot或stack？打開一列組爲多列

Question

我的數據是這樣的：

2  PresentationID 12954 
5   Attendees  65 
6   Downloads  0 
7   Questions  0 
8    Likes  11 
9    Tweets  0 
10    Polls  0 
73 PresentationID 12953 
76   Attendees  64 
77   Downloads  31 
78   Questions  0 
79    Likes  11 
80   Tweets  0 
81    Polls  0 
143 PresentationID 12951 
146  Attendees  64 
147  Downloads  28 
148  Questions  2 
149   Likes  2 
150   Tweets  0 
151   Polls  0 

，我需要得到它的格式爲：

PresentationID Attendees Downloads Questions Likes Tweets Polls 
0   12954   65   0   0  11  0  0 
1   12953   64   31   6  0  4 
2   12892  204   0   0  14  0  0 

我已經試過GROUPBY的幾種組合，支點，並無濟於事。任何建議不勝感激。謝謝。

Answer 1

您可以使用cumcount與pivot：

print (df) 
     A    B  C 
0  2 PresentationID 12954 
1  5  Attendees  65 
2  6  Downloads  0 
3  7  Questions  0 
4  8   Likes  11 
5  9   Tweets  0 
6 10   Polls  0 
7 73 PresentationID 12953 
8 76  Attendees  64 
9 77  Downloads  31 
10 78  Questions  0 
11 79   Likes  11 
12 80   Tweets  0 
13 81   Polls  0 
14 143 PresentationID 12951 
15 146  Attendees  64 
16 147  Downloads  28 
17 148  Questions  2 
18 149   Likes  2 
19 150   Tweets  0 
20 151   Polls  0 

df['G'] = df.groupby('B').cumcount() 
df = df.pivot(index='G', columns='B', values='C') 
print (df) 
B Attendees Downloads Likes Polls PresentationID Questions Tweets 
G                  
0   65   0  11  0   12954   0  0 
1   64   31  11  0   12953   0  0 
2   64   28  2  0   12951   2  0 

---

df = pd.pivot(index=df.groupby('B').cumcount(), columns=df.B, values=df.C) 
print (df) 
B Attendees Downloads Likes Polls PresentationID Questions Tweets 
0   65   0  11  0   12954   0  0 
1   64   31  11  0   12953   0  0 
2   64   28  2  0   12951   2  0