Add row to a data frame with total sum for each column

See adorn_totals() from the janitor package:

library(janitor)
x %>%
  adorn_totals("row")

#>  Language Files   LOC
#>       C++  4009 15328
#>      Java   210   876
#>    Python    35   200
#>     Total  4254 16404

The numeric columns remain of class numeric.

Disclaimer: I created this package, including adorn_totals() which is made for precisely this task.

A tidyverse way to do this would be to use bind_rows (or eventually add_row) and summarise to compute the sums. Here the issue is that we want sums for all but one, so a trick would be:

summarise_all(x, ~if(is.numeric(.)) sum(.) else "Total")

In one line:

x %>%
  bind_rows(summarise_all(., ~if(is.numeric(.)) sum(.) else "Total"))

Edit with dplyr >=1.0

One can also use across(), which is slightly more verbose in this case:

x %>%
  bind_rows(summarise(.,
                      across(where(is.numeric), sum),
                      across(where(is.character), ~"Total")))