Comparing single- and double-bracket subsetting for atomic vectors

bracket.R

my_letters <- c("A", "B", "C", "D", "E")
bench::mark(for (i in 1:10000) NULL)
#> # A tibble: 1 × 6
#>   expression                   min   median `itr/sec` mem_alloc `gc/sec`
#>   <bch:expr>              <bch:tm> <bch:tm>     <dbl> <bch:byt>    <dbl>
#> 1 for (i in 1:10000) NULL    312µs    332µs     2972.    38.9KB     36.3
bench::mark(for (i in 1:10000) my_letters[3], for (i in 1:10000) my_letters[[3]])
#> # A tibble: 2 × 6
#>   expression                             min median `itr/sec` mem_alloc `gc/sec`
#>   <bch:expr>                         <bch:t> <bch:>     <dbl> <bch:byt>    <dbl>
#> 1 for (i in 1:10000) my_letters[3]     941µs  979µs     1010.   10.25KB     85.6
#> 2 for (i in 1:10000) my_letters[[3]]   933µs  988µs     1003.    8.16KB     82.0
y <- 3
bench::mark(for (i in 1:10000) my_letters[y], for (i in 1:10000) my_letters[[y]])
#> # A tibble: 2 × 6
#>   expression                             min median `itr/sec` mem_alloc `gc/sec`
#>   <bch:expr>                         <bch:t> <bch:>     <dbl> <bch:byt>    <dbl>
#> 1 for (i in 1:10000) my_letters[y]     884µs  925µs     1068.    9.48KB     69.4
#> 2 for (i in 1:10000) my_letters[[y]]   844µs  893µs     1112.    8.43KB     75.2