Copying values from multiple excel files to a single one with python

Question

I want to replicate the values from a folder of numerous excel files that has values in columns a through g into a single excel file.

The following piece of code has been tested by me:

`  import os
    import pandas as pd

   # Specify the input folder containing Excel files
    input_folder = 'C:/Users/User/Desktop/FilesToProcess'

   # Create an empty DataFrame to store the selected data
    selected_data = pd.DataFrame()

   # Loop through all Excel files in the input folder
    for file_name in os.listdir(input_folder):
    if file_name.endswith('.xlsx'):
   # Read in the Excel file and select the desired columns
    df = pd.read_excel(os.path.join(input_folder, file_name), usecols='A:G')
   # Append the selected data to the main DataFrame
    selected_data = selected_data.append(df)[df.columns.tolist()]

   # Specify the output file name and sheet name
    output_file = 'C:/Users/User/Desktop/output1.xlsx'
    output_sheet_name = 'Sheet1'

   # Write the selected columns to a new Excel file
    with pd.ExcelWriter(output_file) as writer:
    selected_data.to_excel(writer, sheet_name=output_sheet_name, index=False)`

Although it initially functions as intended, after a few files, the columns become messed up. It starts copying values in columns > G specifically. Due to the nature of the data, I am unable to provide a result example.