But, strangely, Jupyter doesn't also give you a REPL (like, say, R Studio does). I'm always making new cells in the middle to output the column names of my spreadsheet, and then I have to delete them. I used to just always have an ipython REPL running and test things out in there as I write. You can start a ipython instance on the same kernel but I found that messed up my plots when I did that IIRC.