问题是：
基于user_id列,我想获取rating和product_id列的值.可以有多个具有相同user_id的条目.我想获取所有用户的记录,并具有rating和product_id列的值,但是对于用户未评分的电影,该电影应显示为Nan,但仍应检索product_id.以下是提供一些数据的表.
| product_id | user_id | user_name | rating |
|-------------|-----------------|----------------------------------------------|--------|
| B0009XRZ92 | A2JFZLAUG3YFQ7 | Entropy Babe "EB" | 5 |
| B0009XRZ92 | A22HGAAO8KZ2N3 | R. Metzelar | 5 |
| B000067A8B | A2NJO6YE954DBH | Lawrance M. Bernabo | 4 |
| B0009XRZ92 | A3HE4MYMWK4AER | Rebecca M. Eddy "Foster Mom and Untbunny" | 5 |
| B003A3R3ZY | A9A2PR663ED1V | Roger D. Goff | 5 |
| B0009XRZ92 | A2MRZDJF90JC1U | Suzanne K. Armstrong "Suzy Q" | 5 |
| B0009XRZ92 | A2YNBDT3170PCR | C. O'Hern | 5 |
| B0009XRZ92 | A10VJ7BDVCPKEZ | Carol S. Bottom | 5 |
| B0009XRZ92 | AAAQO894MG80B | Paul J. Michko | 5 |
| B00067BBQE | A9A2PR663ED1V | Roger D. Goff | 5 |
| B0009XRZ92 | A31S5QUMFR8NH2 | Dana L. Jordan "Mom of Twins" | 5 |
| B0009XRZ92 | A2DS24DHXUH0GM | Gaz Rev(iewer) | 4 |
| B00006AUMZ | A2NJO6YE954DBH | Lawrance M. Bernabo | 4 |
| B0009XRZ92 | A16FRHL2ZC7EUR | M. Claytor | 5 |
| B0009XRZ92 | A3AV8R0A62PP1N | MARCUSHELBLINZ "mmmacman" | 5 |
| B0009XRZ92 | A3QN84C38DE9FU | Gillian M. Kratzer | 5 |
| B0009XRZ92 | A36MLTLVQFEQYL | Yossarian "alienated socialist" | 5 |
| B00006AUMD | A2NJO6YE954DBH | Lawrance M. Bernabo | 4 |
What I want to do is:
To take one
user_idat a time and display theratingandproduct_id
columns value for that user for all the movies in the table and if the
user didn’t rate some movies then the record should be displayed with
theproduct_idvalue andratingas Nan and the whole process should be repeated for all the users.
例如,user_id：A2NJO6YE954DBH的记录将如下所示：
| product_id | rating |
|------------|--------|
| B000067A8B | 4 |
| B00006AUMD | 4 |
| B00006AUMD | 4 |
| B0009XRZ92 | Nan |
| B003A3R3ZY | Nan |
| B00067BBQE | Nan |
| . | . |
| . | . |
| . | . |
我尝试使用Pandas Library为此编写代码,但无济于事.这就是我所做的全部,但未输出我想要的.
import pandas as pd
df =pd.read_csv('out.csv')
unique_users=df.user_id.unique()
for x,y in enumerate(unique_users):
print(df[['rating','product_id']].where(df.user_id==y))
请帮帮我..谢谢
最佳答案
如果我理解正确,则可以在这里使用
原文链接：https://www.f2er.com/python/533153.htmlpd.pivot_table()：
df_new=df.pivot_table(index='user_id',columns='product_id',values='rating').rename_axis(None,1)
print(df_new)
B000067A8B B00006AUMD B00006AUMZ B00067BBQE \
user_id
A10VJ7BDVCPKEZ NaN NaN NaN NaN
A16FRHL2ZC7EUR NaN NaN NaN NaN
A2DS24DHXUH0GM NaN NaN NaN NaN
A2NJO6YE954DBH 4.0 4.0 4.0 NaN
A2YNBDT3170PCR NaN NaN NaN NaN
A36MLTLVQFEQYL NaN NaN NaN NaN
A3HE4MYMWK4AER NaN NaN NaN NaN
A3QN84C38DE9FU NaN NaN NaN NaN
AAAQO894MG80B NaN NaN NaN NaN
A22HGAAO8KZ2N3 NaN NaN NaN NaN
A2JFZLAUG3YFQ7 NaN NaN NaN NaN
A2MRZDJF90JC1U NaN NaN NaN NaN
A31S5QUMFR8NH2 NaN NaN NaN NaN
A3AV8R0A62PP1N NaN NaN NaN NaN
A9A2PR663ED1V NaN NaN NaN 5.0
B0009XRZ92 B003A3R3ZY
user_id
A10VJ7BDVCPKEZ 5.0 NaN
A16FRHL2ZC7EUR 5.0 NaN
A2DS24DHXUH0GM 4.0 NaN
A2NJO6YE954DBH NaN NaN
A2YNBDT3170PCR 5.0 NaN
A36MLTLVQFEQYL 5.0 NaN
A3HE4MYMWK4AER 5.0 NaN
A3QN84C38DE9FU 5.0 NaN
AAAQO894MG80B 5.0 NaN
A22HGAAO8KZ2N3 5.0 NaN
A2JFZLAUG3YFQ7 5.0 NaN
A2MRZDJF90JC1U 5.0 NaN
A31S5QUMFR8NH2 5.0 NaN
A3AV8R0A62PP1N 5.0 NaN
A9A2PR663ED1V NaN 5.0