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Translate desc(col) to -col inside arrange() #227

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merged 2 commits into from
Mar 21, 2021

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markfairbanks
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@hadley
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hadley commented Mar 20, 2021

And that works for character vectors?

@markfairbanks
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Yep. It's their recommended way so that you can sort character vectors descending using their radix sorting.

library(data.table)
library(dplyr)

dt <- data.table(x = sample(letters, 100000, TRUE))

bench::mark(
  minus = dt[order(-x)],
  desc = dt[order(desc(x))],
)
#> # A tibble: 2 x 6
#>   expression      min   median `itr/sec` mem_alloc `gc/sec`
#>   <bch:expr> <bch:tm> <bch:tm>     <dbl> <bch:byt>    <dbl>
#> 1 minus        1.16ms   1.71ms    543.      2.85MB     13.3
#> 2 desc       437.11ms 450.29ms      2.22    8.06MB      0

@hadley hadley merged commit f8ef87a into tidyverse:master Mar 21, 2021
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hadley commented Mar 21, 2021

Good to know, thanks!

@markfairbanks markfairbanks deleted the desc-as-minus branch March 28, 2021 13:56
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