Streamlit - Settings page with session state

multipage_settings_app.py

import streamlit as st
from persist import persist, load_widget_state


def main():
    if "page" not in st.session_state:
        # Initialize session state.
        st.session_state.update({
            # Default page.
            "page": "home",

            # Radio, selectbox and multiselect options.
            "options": ["Hello", "Everyone", "Happy", "Streamlit-ing"],

            # Default widget values.
            "text": "",
            "slider": 0,
            "checkbox": False,
            "radio": "Hello",
            "selectbox": "Hello",
            "multiselect": ["Hello", "Everyone"],
        })

    page = st.sidebar.radio("Select your page", tuple(PAGES.keys()), format_func=str.capitalize)

    PAGES[page]()


def page_home():
    st.write(
        f"""
        Settings values
        ---------------

        - **Input**: {st.session_state.text}
        - **Slider**: `{st.session_state.slider}`
        - **Checkbox**: `{st.session_state.checkbox}`
        - **Radio**: {st.session_state.radio}
        - **Selectbox**: {st.session_state.selectbox}
        - **Multiselect**: {", ".join(st.session_state.multiselect)}
        """
    )


def page_settings():
    st.header("Change settings")

    st.text_input("Input", key=persist("text"))
    st.slider("Slider", 0, 10, key=persist("slider"))
    st.checkbox("Checkbox", key=persist("checkbox"))
    st.radio("Radio", st.session_state["options"], key=persist("radio"))
    st.selectbox("Selectbox", st.session_state["options"], key=persist("selectbox"))
    st.multiselect("Multiselect", st.session_state["options"], key=persist("multiselect"))


PAGES = {
    "home": page_home,
    "settings": page_settings,
}


if __name__ == "__main__":
    load_widget_state()
    main()

persist.py

from streamlit import session_state as _state

_PERSIST_STATE_KEY = f"{__name__}_PERSIST"


def persist(key: str) -> str:
    """Mark widget state as persistent."""
    if _PERSIST_STATE_KEY not in _state:
        _state[_PERSIST_STATE_KEY] = set()

    _state[_PERSIST_STATE_KEY].add(key)

    return key


def load_widget_state():
    """Load persistent widget state."""
    if _PERSIST_STATE_KEY in _state:
        _state.update({
            key: value
            for key, value in _state.items()
            if key in _state[_PERSIST_STATE_KEY]
        })

Hey man, many thanks for this snippet!