Toggle hide/show sidebar from Python

FYI, for anyone still looking for how to toggle the sidebar state programmatically, see below a simple example (works for me on Streamlit 1.11.1):

import streamlit as st

# Initialize a session state variable that tracks the sidebar state (either 'expanded' or 'collapsed').
if 'sidebar_state' not in st.session_state:
    st.session_state.sidebar_state = 'expanded'

# Streamlit set_page_config method has a 'initial_sidebar_state' argument that controls sidebar state.

# Show title and description of the app.
st.title('Example: Controlling sidebar programmatically')
st.sidebar.markdown('This is an example Streamlit app to show how to expand and collapse the sidebar programmatically.')

# Toggle sidebar state between 'expanded' and 'collapsed'.
if st.button('Click to toggle sidebar state'):
    st.session_state.sidebar_state = 'collapsed' if st.session_state.sidebar_state == 'expanded' else 'expanded'
    # Force an app rerun after switching the sidebar state.