Multi-page apps

Our Streamlit apps thus far have all been single pages, where all or nearly all the information in the app has been visible to us with a simple scroll. However, Streamlit also has multi-page functionality. Multi-page apps are a powerful tool for creating apps that are not limited to one page of content and can extend the user experience that comes with Streamlit. For example, the Streamlit data team currently primarily builds multi-page apps, having a new app for each project or team that they are creating Streamlit apps for.

For our first multi-page app, we’re going to focus on separating the map section of the trees app from the rest of the graphs in two separate apps. The way Streamlit creates multi-page apps is it looks in the same directory as our Streamlit app for a folder called pages and then runs each Python file inside the pages folder as its own Streamlit app. To do this, create a new folder inside pretty_trees called pages, and then put a file...