app.py

#!/usr/bin/env python

import gradio as gr
import pandas as pd

df_empty = pd.DataFrame([], columns=['a', 'b'])

with gr.Blocks() as demo:
    df = gr.Dataframe(interactive=False)
    btn = gr.Button()
    text = gr.Textbox()
    btn.click(fn=lambda x: (gr.update(value=df_empty), len(x)),
              inputs=df,
              outputs=[df, text])
demo.queue().launch()