data/develop/api-reference/control-flow/rerun.md

metadata

title: st.rerun
slug: /develop/api-reference/execution-flow/st.rerun
description: st.rerun will rerun the script immediately.

Caveats for st.rerun

st.rerun is one of the tools to control the logic of your app. While it is great for prototyping, there can be adverse side effects:

• Additional script runs may be inefficient and slower.
• Excessive reruns may complicate your app's logic and be harder to follow.
• If misused, infinite looping may crash your app.

In many cases where st.rerun works, callbacks may be a cleaner alternative. Containers may also be helpful.

A simple example in three variations

Using st.rerun to update an earlier header

import streamlit as st

if "value" not in st.session_state:
    st.session_state.value = "Title"

##### Option using st.rerun #####
st.header(st.session_state.value)

if st.button("Foo"):
    st.session_state.value = "Foo"
    st.rerun()

Using a callback to update an earlier header

##### Option using a callback #####
st.header(st.session_state.value)

def update_value():
    st.session_state.value = "Bar"

st.button("Bar", on_click=update_value)

Using containers to update an earlier header

##### Option using a container #####
container = st.container()

if st.button("Baz"):
    st.session_state.value = "Baz"

container.header(st.session_state.value)