R - Adding a total row in Excel output - r

Question

I want to add a total row (as in the Excel tables) while writing my data.frame in a worksheet.
Here is my present code (using openxlsx):
writeDataTable(wb=WB, sheet="Data", x=X, withFilter=F, bandedRows=F, firstColumn=T)
X contains a data.frame with 8 character variables and 1 numeric variable. Therefore the total row should only contain total for the numeric row (it will be best if somehow I could add the Excel total row feature, like I did with firstColumn while writing the table to the workbook object rather than to manually add a total row).
I searched for a solution both in StackOverflow and the official openxslx documentation but to no avail. Please suggest solutions using openxlsx.
EDIT:
Adding data sample:
A B C D E F G H I
a b s r t i s 5 j
f d t y d r s 9 s
w s y s u c k 8 f
After Total row:
A B C D E F G H I
a b s r t i s 5 j
f d t y d r s 9 s
w s y s u c k 8 f
na na na na na na na 22 na

Answer 1

library(janitor)
adorn_totals(df, "row")
#> A B C D E F G H I
#> a b s r t i s 5 j
#> f d t y d r s 9 s
#> w s y s u c k 8 f
#> Total - - - - - - 22 -
If you prefer empty space instead of - in the character columns you can specify fill = "" or fill = NA.

Answer 2

Assuming your data is stored in a data.frame called df:
df <- read.table(text =
"A B C D E F G H I
a b s r t i s 5 j
f d t y d r s 9 s
w s y s u c k 8 f",
header = TRUE,
stringsAsFactors = FALSE)
You can create a row using lapply
totals <- lapply(df, function(col) {
ifelse(!any(!is.numeric(col)), sum(col), NA)
})
and add it to df using rbind()
df <- rbind(df, totals)
head(df)
A B C D E F G H I
1 a b s r t i s 5 j
2 f d t y d r s 9 s
3 w s y s u c k 8 f
4 <NA> <NA> <NA> <NA> <NA> <NA> <NA> 22 <NA>