Write to StringIO object using Pandas Excelwriter?

Question

I can pass a StringIO object to pd.to_csv() just fine:

io = StringIO.StringIO()
pd.DataFrame().to_csv(io)

But when using the excel writer,

Answer 1

For those not using xlsxwriter as their engine= for to_excel here is a solution to use openpyxl in memory:

in_memory_file = StringIO.StringIO()
xlw = pd.ExcelWriter('temp.xlsx', engine='openpyxl')
# ... do many .to_excel() thingies
xlw.book.save(in_memory_file)
# if you want to read it or stream to a client, don't forget this
in_memory_file.seek(0)

explanation: the ExcelWriter wrapper class exposes the engines individual workbook through the .book property. For openpyxl you can then use the Workbook.save method as usual!