What is the most efficient way to sum all columns whose name starts with a pattern?

Question

My goal is to sum all values in columns that start with the prefix skill_ in a data.table. I would prefer a solution using data.table

Answer 1

Here is a dplyr solution:

library(dplyr)

DT %>% mutate(count = DT %>% select(starts_with("skill_")) %>% rowSums())