Selecting from data.table by row is very slow #3735

allIterations <- data.frame(v1 = runif(1e5), v2 = runif(1e5))
DoSomething <- function(row) {
  someCalculation <- row[["v1"]] + 1
}
system.time(
       {
         for (r in 1:nrow(allIterations)) {
           DoSomething(allIterations[r, ])
         }
       }
     )
##   user  system elapsed 
##   4.50    0.02    4.55 

allIterations <- as.data.table(allIterations)
system.time(
       {
         for (r in 1:nrow(allIterations)) {
           DoSomething(allIterations[r, ])
         }
       }
     )
##   user  system elapsed 
##   53.78   25.05   78.46