Applying a function to each row of a data.table

Question

I looking for a way to efficiently apply a function to each row of data.table. Let\'s consider the following data table:

library(data.table)
library(stringr)         


        

Answer 1

One option would be to add a row number

x[, r := 1:nrow(x)]

and then group by r:

x[, list(a, str_split(b, ' ')[[1]]), by = r]

I'm wondering if there are better solutions?