Can Pandas types (e.g. DataFrame and Series) be used with PyXLL? Tony Roberts 04 October 2019 09:47 Yes, pandas DataFrames and Series can be used as arguments and return types of PyXLL user defined functions. See How to use Pandas in Excel for details. Related articles Can Python be used to replace VBA? Do I have 32 bit or 64 bit Excel? Writing arrays back to Excel Can Excel call Python functions in parallel? Does Python code running in PyXLL run at the same speed as normal Python code?