#Sample of how make download button for csv or xlsx file
def to_excel(df):
output = BytesIO()
writer = pd.ExcelWriter(output, engine='xlsxwriter')
df.to_excel(writer, index=False, sheet_name='Sheet1')
workbook = writer.book
worksheet = writer.sheets['Sheet1']
format1 = workbook.add_format({'num_format': '0.00'})
worksheet.set_column('A:A', None, format1)
writer.save()
processed_data = output.getvalue()
return processed_data
df_xlsx = to_excel(df_upload)
st.download_button(label='📥 Download Current Result',
data=df_xlsx,
file_name='df_result.xlsx')