Streamlit

streamlit is a server application
On every save of the .py file and on every user ineraction with the app, the whole script reruns. Callbacks (on_change, on_click) are computed before the rest of the script.
st.sidebar.selectbox puts select box in left sidebar.
To run method only once, there is @st.cache_data decorator.
On page refresh session state get cleaned
st.cache_data creates a new copy of the data at each function call
st.cache_resource returns the cached object itself

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