Two ways of formatting time periods from numeric

benchmark.R

library(microbenchmark)
long_way <- function(time_vector) {
  return(
    time_vector |> 
    lapply(function(x){
      (x |> 
         str_match_all("[0-9]{1}") |> 
         unlist() |> 
         rev())[1:4] |> 
        (\(time){
          time[is.na(time)] <- "0"
          paste0(time[4],time[3],":",time[2],time[1])
        })()
    }) |> unlist()
  )
}
longest_way <- function(time_vector) {
  return(
    time_vector |> 
      lapply(function(x){
        time <- x |> 
          as.character() |> 
          strsplit("\\.*") |> 
          (\(time){
            time <- rev(time[[1]])[1:4]
          })()
        time[is.na(time)] <- 0
        paste0(time[4],time[3],":",time[2],time[1])
      }) |> unlist()
  )
}
short_way <- function(time_vector) {
  return(
    time_vector |> 
           lapply(function(x){
             x |> str_pad(4, "left", "0") |> stringr::str_replace("(.{2})(.{2})", "\\1:\\2")
           })|> unlist()
    )
}
shorter_way <- function(time_vector) {
  return(
    time_vector |> 
      lapply(function(x){
        prefixed <- sprintf("%04d", x)
        return(
          paste0(substr(prefixed,1,2),":",substr(prefixed,3,4))
        )
      })|> unlist()
  )
}
mbm = microbenchmark(
  long = long_way(1:2000),
  longest = longest_way(1:2000),
  short = short_way(1:2000),
  shortest = shorter_way(1:2000),
  times=50
)
mbm
# Unit: milliseconds
# expr       min         lq      mean    median        uq       max neval
# long  48.74027  53.048229  58.81344  55.52145  63.67269  80.42932    50
# longest  32.54070  34.525115  38.54215  36.34376  39.71092  54.13282    50
# short 147.91870 162.895009 174.57177 176.11646 184.59249 207.07270    50
# shortest   9.14919   9.854754  11.47535  11.06433  11.55994  24.03890    50
plot(mbm)