How to Append a Pandas DataFrame to an Existing Excel Sheet Without Overwriting?

Append an Existing Excel Sheet with a New Dataframe Using Python Pandas

In this scenario, the code provided is designed to iterate through a folder containing Excel files, apply specific data transformations to each file, and then append the modified data to an existing central Excel file ('master_data.xlsx'). However, the current implementation overwrites the existing 'master_data.xlsx' each time it is executed. The goal is to append the new data to the bottom of the existing Excel sheet without overwriting it.

To achieve this, a solution is needed that can access the existing 'master_data.xlsx' file, merge the new data into it, and save it without overwriting the original content. Here's how it can be accomplished:

1. Import Pandas and OpenPyxl:

import pandas as pd
import openpyxl

2. Load the Existing 'master_data.xlsx' File:

master_data = pd.read_excel('master_data.xlsx')

3. Iterate Through the New Dataframes:

for data in dfList:
    # Append the new data to the existing dataframe
    master_data = master_data.append(data)

4. Save the Updated 'master_data.xlsx' File:

master_data.to_excel('master_data.xlsx', index=False)

This updated approach maintains the existing contents of 'master_data.xlsx' and appends the new data to the bottom of the sheet.

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