Added which_ to na.omit as well.
Added which_ to na.omit as well.

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