It seems that I should probably be using st.altair_chart and have tried to wrangle the data frame so that it will play nice with altair, but no luck so far. Any thoughts appreciated.
I suspect you might get the chart you are looking for if you make the Date column an index instead, but you’re right, in the situation where st.line_chart doesn’t give you what you want, using st.altair_chart is the way to proceed.