Dataframe, reverse order of rows in one single column according to groups of multiple factor columns

Question

I am trying to reverse the rows of one column of a dataframe by group, where grouping is driven by multiple factor columns.

I would like to go from here

I would like to reverse numeric values of Col5 according to selected groups, so as to obtain this:

All the other columns are factor

I tried with this code, but it failed

reord<-a %>% dplyr::group_by(Col1,Col2,Col4)%>% dplyr::mutate(reve=rev(Col5))

Do you have any suggestion? Any help is highly appreciated Thanks in advance

Answer 1

Made it.

Here my solution (also used some code from forums, so thanks anyway).

split<-a %>% ##a is the original dataframe
       group_split(Col1, Col2, Col4) ## the dataframe is subset to tibble


split1<-lapply(split, function(x) dplyr::mutate(x, reve=rev(Col5))) ## rev() is applied to all columns of interest of the list

reord1<-bind_rows(split1, .id = 'id') ## the list objects are rbound to obtain the dataframe with either original values in Col5 and reverse values in the new column "reve"

It worked well