?DFrame leads to documentation for DataFrame and the only mention of DFrame is related to make_zero_col_DFrame. So, what is DFrame exactly?

Hi Dario,

Have a look at the showClass("DFrame") call. DFrame extends DataFrame directly. You don't have to worry about the specifics here. Just know that you should be using the DataFrame constructor. It is related to changes to eventually make the DataFrame class virtual.

> showClass("DFrame")
Class "DFrame" [package "S4Vectors"]

Slots:

Name:           rownames             nrows          listData       elementType
Class: character_OR_NULL           integer              list         character

Name:    elementMetadata          metadata
Class: DataFrame_OR_NULL              list

Extends: 
Class "DataFrame", directly
Class "RectangularData", by class "DataFrame", distance 2
Class "SimpleList", by class "DataFrame", distance 2
Class "DataFrame_OR_NULL", by class "DataFrame", distance 2, with explicit coerce
Class "List", by class "DataFrame", distance 3
Class "Vector", by class "DataFrame", distance 4
Class "list_OR_List", by class "DataFrame", distance 4, with explicit coerce
Class "Annotated", by class "DataFrame", distance 5
Class "vector_OR_Vector", by class "DataFrame", distance 5, with explicit coerce

Best regards,

Marcel