Flatten a Pandas DF by column name

Use melt function 

https://stackoverflow.com/questions/38612154/pandas-flatten-a-dataframe-to-a-single-column

Plotly plot pandas data frame by index

 Plotly plot pandas data frame by index

https://stackoverflow.com/questions/57178206/use-pandas-index-in-plotly-express

 

Merge two data frames by index

https://stackoverflow.com/questions/40468069/merge-two-dataframes-by-index