How Can I Append a New DataFrame to an Existing Excel Sheet Without Overwriting?

Append New DataFrame to Existing Excel Sheet

This Python script assists in appending new dataframes to an existing Excel sheet named "master_data.xlsx." Instead of overwriting the current content, it will add the new rows to the bottom of the existing sheet.

Code Enhancements:

The original code included a loop to process multiple Excel files. To focus on appending to an existing sheet, we have excluded the loop and assumed that the "master_data.xlsx" file is the one you wish to append to.

Helper Function:

We introduced a helper function called append_df_to_excel that handles the appending process. This function offers the following benefits:

• Appends Without Overwriting: It ensures that the new DataFrame is added to the bottom of the existing sheet, preserving the original data.
• Auto-Detect Last Row: It calculates the last row in the existing sheet and adds the new data starting from the next row.
• Custom formatting: It allows you to specify Excel formatting options for different data types (e.g., currency, date, time).

Revised Code:

import pandas as pd
import openpyxl

# Load "master_data.xlsx" into a DataFrame
df_master = pd.read_excel("master_data.xlsx")

# Append new DataFrame to "master_data.xlsx" without overwriting
append_df_to_excel(
    "master_data.xlsx",
    new_data,
    header=False,  # Assuming new DataFrame does not have a header
    index=False,  # Assuming new DataFrame does not have an index
)

Usage:

Simply replace new_data with your desired DataFrame and run the code. The new DataFrame will be appended to the bottom of the "master_data.xlsx" sheet without any modifications to the existing data.

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