R dplyr solution vs. Base R solution for the slect column total

Hello,

I am looking for a dplyr or base R solution for the column total - JUST FOR THE LAST COLUMN in the example below. The following code works, giving me the total for each column - This is not exactly what I want.
rbind(test, colSums(test))

I only want the total for the very last column.  I am struggling with 
this part of the code: rbind(test, c("Total", colSums(test, ...))) I have searched for a solution on Stack Oveflow.  I found  some mutate() code for the cumsum but no luck for the select column total.  Is there a dplyr solution for the select column total?

Any hints will be appreciated.

Thanks,

Pradip Muhuri


####### The following is from the console - the R script with reproducible example is also appended.


mrjflag cocflag inhflag halflag oidflag count
1        0       0       0       0       0   256
2        0       0       0       1       1   256
3        0       0       1       0       1   256
4        0       0       1       1       1   256
5        0       1       0       0       1   256
6        0       1       0       1       1   256
7        0       1       1       0       1   256
8        0       1       1       1       1   256
9        1       0       0       0       1   256
10       1       0       0       1       1   256
11       1       0       1       0       1   256
12       1       0       1       1       1   256
13       1       1       0       0       1   256
14       1       1       0       1       1   256
15       1       1       1       0       1   256
16       1       1       1       1       1   256
17       8       8       8       8      15  4096



#######################  below is the reproducible example 
########################
library(dplyr)
# generate data
dlist <- rep( list( 0:1 ), 4 )
data <- do.call(expand.grid, drbind)
data$id <- 1:nrow(data)
names(data) <- c('mrjflag', 'cocflag', 'inhflag', 'halflag')


# mutate a column and then sumamrize
 test <- data %>%
      mutate(oidflag= ifelse(mrjflag==1 | cocflag==1 | inhflag==1 | halflag==1, 1, 0)) %>%
      group_by(mrjflag,cocflag, inhflag, halflag, oidflag) %>%
      summarise(count=n()) %>%
      arrange(mrjflag,cocflag, inhflag, halflag, oidflag)


#  This works, giving me the total for each column - This is not what I exactly want.
   rbind(test, colSums(test))

# I only want the total for the very last column rbind(test, 
c("Total", colSums(test, ...)))

Pradip K. Muhuri, PhD
SAMHSA/CBHSQ
1 Choke Cherry Road, Room 2-1071
Rockville, MD 20857
Tel: 240-276-1070
Fax: 240-276-1260


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