How to clear screen/make blank again?

🎈 Using Streamlit
#1

I want to print some text, then clear the screen, and then print some more text. Is there a command that I can use to accomplish this?

#2

You can use st.empty to keep a placeholder that can be cleaned whenever you want to add new elements.

Here is a unnecessarily convoluted fun example:

emptyContainer

import streamlit as st

if "page" not in st.session_state:
    st.session_state.page = 0

def nextpage(): st.session_state.page += 1
def restart(): st.session_state.page = 0

placeholder = st.empty()
st.button("Next",on_click=nextpage,disabled=(st.session_state.page > 3))

if st.session_state.page == 0:
    # Replace the placeholder with some text:
    placeholder.text(f"Hello, this is page {st.session_state.page}")

elif st.session_state.page == 1:
    # Replace the text with a chart:
    placeholder.line_chart({"data": [1, 5, 2, 6]})

elif st.session_state.page == 2:
# Replace the chart with several elements:
    with placeholder.container():
        st.write("This is one element")
        st.write("This is another")
        st.metric("Page:", value=st.session_state.page)

elif st.session_state.page == 3:
    placeholder.markdown(r"$f(x) = \exp{\left(x^🐈\right)}$")

else:
    with placeholder:
        st.write("This is the end")
        st.button("Restart",on_click=restart)
#3

This doesn’t seem to work when not triggered by a UI event. How does one clear the screen in response to some other kind of event - e.g. expiration of a timer, or a notification completion of a task coming from a remote service?