how to download excel file in python and streamlit?

Question

I have a Python script that read files and convert it to dataframe using Python and streamlit. Then I want to create a function to allows the user to download this dataframe as an Excel file with extension .xls.

So I tried to read the dataframe and convert it to an Excel file using these two functions:

pd.ExcelWriter
df.to_excel

But when I try to download the file using a link the file doesn't download and displays this error:

Failed-Network error

Code:

import pandas as pd 
import streamlit as st

writer = pd.ExcelWriter('update2.xlsx')
df.to_excel(writer, index = False, header=True,encoding='utf-8')
with open(writer,'rb') as f:
    b64 = base64.b64encode(f.read())
    href = f'<a href="data:file/xls;base64,{b64}" download="new_file.{extension}">Download {extension}</a>'

st.write(href, unsafe_allow_html=True)

Answer 1

With the streamlit latest release(above 1.0.0):

Use

st.download_button

Displays a download button widget.

This is useful when you would like to provide a way for your users to download a file directly from your app.

Note that the data to be downloaded is stored in memory while the user is connected, so it's a good idea to keep file sizes under a couple of hundred megabytes to conserve memory.

Here is a sample code from the discussion, that can be helpful to download excel files...

import pandas as pd
from io import BytesIO
from pyxlsb import open_workbook as open_xlsb
import streamlit as st

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)
st.download_button(label='📥 Download Current Result',
                                data=df_xlsx ,
                                file_name= 'df_test.xlsx')