app.py

import streamlit as st
import shutil
import os
if os.path.exists("./output/") == False:
    os.mkdir("./output/")
if st.download_button(label="Download output "+str(len(os.listdir("./output/"))), data=None, file_name='output.zip', mime='application/x-zip'):
    st.write("download")
st.write(os.listdir("./"))