Pandas not exporting all columns

Question

I am new to pandas and I have googled my problem but did not get any help.

Problem Statement: When I save final CSV using df.to_csv() after performing cumsum() on one of the column amount, My CSV only showing one column amount but I want all the columns in my final CSV.

Sample Data:

*------------------------------------------------*
|effective_date | account_id | currency | amount |
*------------------------------------------------*
|   12/26/19          1        USD         50    |
|   12/27/19          1        USD         70    |
|   11/06/19          2        USD         90    |
|   11/07/19          2        USD         30    |
*------------------------------------------------*

My Code using Jupyter Notebook:

import pandas as pd
df = pd.read_csv('payments.csv', index_col=0)

df['effective_when'] = pd.to_datetime(df['effective_when'])

df = df.groupby(['account_id', 'currency', 'effective_date']).sum().groupby(level=[0]).cumsum()

df.to_csv ('cumulativePayments.csv')

Current Result:

*------*
|amount|
*------*
| 50   |
| 120  |
| 90   |
| 120  |
*------*

Expected Result:

*------------------------------------------------*
|effective_date | account_id | currency | amount |
*------------------------------------------------*
|   12/26/19          1       USD          50    |
|   12/27/19          1       USD          120   |
|   11/06/19          2       USD          90    |
|   11/07/19          2       USD          120   |
*------------------------------------------------*

how can I achieve this?

Answer 1

I think you can split code to create DataFrame with aggregation sum and then reaasign amount columns filled by cumulative sums:

df = pd.read_csv('payments.csv', index_col=0)

df['effective_date'] = pd.to_datetime(df['effective_date'])

df = df.groupby(['account_id', 'currency', 'effective_date'], as_index=False).sum()
df['amount'] = df.groupby('account_id')['amount'].cumsum()
print (df)
   account_id currency effective_date  amount
0           1      USD     2019-12-26      50
1           1      USD     2019-12-27     120
2           2      USD     2019-11-06      90
3           2      USD     2019-11-07     120

df.to_csv('cumulativePayments.csv')

Another idea should be convert first column to datetimes and for write to file remove default index values:

df = pd.read_csv('payments.csv', parse_dates=[0])

df = df.groupby(['account_id', 'currency', 'effective_date'], as_index=False).sum()
df['amount'] = df.groupby('account_id')['amount'].cumsum()

df.to_csv('cumulativePayments.csv', index=False)