import numpy as np
import pandas as pd
import panel as pn
from io import BytesIO

pn.extension(sizing_mode="stretch_width")

data=pd.DataFrame(np.random.randn(100, 4), columns=list('ABCD'))

def get_csv():
    return BytesIO(data.to_csv().encode())

file_download_csv = pn.widgets.FileDownload(filename="data.csv", callback=get_csv, button_type="primary")
file_download_csv

def get_csv_zip():
    output = BytesIO()
    output.name = "data.csv"
    data.to_csv(output, compression="zip")
    output.seek(0)
    return output

file_download_csv_zip = pn.widgets.FileDownload(filename="data.csv.zip", callback=get_csv_zip, button_type="primary")
file_download_csv_zip

def get_xlsx():
    output = BytesIO()
    writer = pd.ExcelWriter(output, engine='xlsxwriter')
    data.to_excel(writer, sheet_name="Data")
    writer.save() # Important!
    output.seek(0) # Important!
    return output

file_download_xlsx = pn.widgets.FileDownload(filename="data.xlsx", callback=get_xlsx, button_type="primary")
file_download_xlsx

def get_json():
    return BytesIO(data.to_json(orient="records").encode())

file_download_json = pn.widgets.FileDownload(filename="data.json", callback=get_json, button_type="primary")
file_download_json

def get_parquet():
    output = BytesIO()
    output.name = "data.parquet"
    data.to_parquet(output)
    output.seek(0)
    return output

file_download_parquet = pn.widgets.FileDownload(filename="data.parquet", callback=get_parquet, button_type="primary")
file_download_parquet

pn.template.FastListTemplate(
    site="Panel", 
    title="File Download", 
    main=[
        "This app demonstrates how to **download a Pandas DataFrame** using different formats.",
        pn.Column(
            pn.pane.HTML("<div style='font-size: 100px;text-align: center'>🐼</div>", height=75, margin=(50,5,10,5)),
            file_download_csv, file_download_csv_zip, file_download_xlsx, file_download_json, file_download_parquet),
    ], main_max_width="768px",
).servable();