根据 python 中的列中的值将 dataframe 导出到多个 csv 文件

Question

I have the following code for exporting each "id" to a separate csv file. Each csv file should be named as an id. Here in my case, we should have three different csv files named 23, 24, and 25. I have the code in below but it gives me an error. Thanks.

import pandas as pd

path = "users/AR/csv files"

for (id), id in df.groupby(['id']):
     group.to_csv(f'{id}.csv', directory=path, index=False)

NameError: name 'group' is not defined

id	date	count
23	2/2/2016	24
24	2/4/2016	56
25	2/3/2016	135
23	3/4/2016	46
24	3/8/2016	176
25	3/9/2016	23
23	3/16/2016	98
24	3/13/2016	114
25	3/17/2016	43

I am expecting three separated csv files in the directory.

Answer 1

Just change:

for (id), id in df.groupby(['id']):

with:

for id, group in df.groupby(['id']):

When iterating groupby object, you get separate grouping value (in id , in your case), from particular group sub-dataframe (here: in group ). id is then used to name a csv file, while group df is exported to csv.

Furthermore, there is no directory parameter in to_csv method. The easiest method is to include path in the filename string, like f'users/AR/csv files/{id}.csv' . If you need OS-agnostic solution, you can use os.path method.

Answer 2

This can be done with list comps:

dfs = [x.reset_index(drop=True) for _, x in df.groupby("id")]
[x.to_csv(f"users/AR/csv files/{x['id'][0]}.csv", index=False) for x in dfs]