chicagopeabodydev-sudo/streamlit-skill

When to use this skill

Use this skill when user interfaces are needed, such as an interface to communicate with a chatbot.

Key concepts

• 1. Streamlit apps are Python scripts that run from top to bottom.
• 2. Every time a browser tab opens for your app, the script is executed and a new session starts.
• 3. As the script executes, Streamlit draws its output live in a browser.
• 4. Every time a user interacts with a widget, your script is re-executed and Streamlit redraws its output in the browser.
• 5. The output value of that widget matches the new value during that rerun.
• 6. Scripts use the Streamlit cache to avoid recomputing expensive functions, so updates are fast.
• 7. Session State lets you save information that persists between reruns.
• 8. Streamlit apps can have multiple pages defined in separate .py files in a pages folder.

Updatable items

Some elements have built-in methods to allow you to update them in-place without rerunning the app.

• st.empty containers can be written to in sequence and will always show the last thing written. They can also be cleared with an additional .empty() called like a method.
• st.dataframe and st.table can be updated with the add_rows() method to append data
• st.progress elements can be updated with additional .progress() calls. They can also be cleared with a .empty() method call.
• st.status containers have an .update() method to change their labels, expanded state, and status.
• st.toast messages can be updated in place with additional .toast() calls.

Chatbot UI (st.chat_message, st.chat_input)

For chat interfaces, use st.chat_message(role) to display messages and st.chat_input() to accept user text. Store message history in st.session_state.messages and iterate to render the conversation. See Example 6 in examples.md.

Additional Resources

• For usage examples, see examples.md
• Streamlit documentation
• Quick reference / cheat sheet
• Animate or update elements