24.2 Organizing code

• Write a function for each approach

mean1 <- function(x) mean(x)
mean2 <- function(x) sum(x) / length(x)

• Keep old functions that you’ve tried, even the failures
• Generate a representative test case

x <- runif(1e5)

• Use bench::mark to compare the different versions (and include unit tests)

bench::mark(
  mean1(x),
  mean2(x)
)[c("expression", "min", "median", "itr/sec", "n_gc")]
#> # A tibble: 2 × 4
#>   expression      min   median `itr/sec`
#>   <bch:expr> <bch:tm> <bch:tm>     <dbl>
#> 1 mean1(x)      392µs    437µs     2276.
#> 2 mean2(x)      186µs    186µs     5305.