Added .BY and i can be list, to ?data.table.
Added .BY and i can be list, to ?data.table.

Rdatatable/data.table,vlulla/data.table,vlulla/data.table,jangorecki/data.table,vlulla/data.table,jangorecki/data.table,jangorecki/data.table,jangorecki/data.table,Rdatatable/data.table,Rdatatable/data.table,vlulla/data.table,Rdatatable/data.table