Rのソートとlocaleについて ref: https://qiita.com/nozma/items/4aea36022ce18a6aa5ca

file0.r

## データの準備
d <- data.frame(
  kana = c("お", "エ", "う", "イ", "あ"),
  letter = c("A", "e", "C", "b", "Z"),
  stringsAsFactors = FALSE
)

file1.r

## 空気を読んだソートをしてくれる
sort(d$kana)

#> [1] "あ" "イ" "う" "エ" "お"

file10.r

## colCaseFirstの指定で大文字を前にできる
stringi::stri_sort(str, locale = "en@colCaseFirst=upper")

#> [1] "A" "A" "a" "a"

file11.r

## 通常のソートは辞書順
str2 <- c("A1", "A12", "A112")
stringi::stri_sort(str2, locale = "en")

#> [1] "A1"   "A112" "A12"

file12.r

## 数字の大きさを考慮したソート（自然順ソート）ができる
stringi::stri_sort(str2, locale = "en@colNumeric=yes") 

#> [1] "A1"   "A12"  "A112"

file2.r

Sys.setlocale(locale = "C")
sort(d$kana)

#> [1] "\343\201\202" "\343\201\206" "\343\201\212" "\343\202\244"
#> [5] "\343\202\250"

file3.r

sorted <- sort(d$kana)
Sys.setlocale(locale = "ja_JP")
sorted

#> [1] "あ" "う" "お" "イ" "エ"

file4.r

withr::with_locale(c("LC_COLLATE" = "C"), sort(d$kana))

#> [1] "あ" "う" "お" "イ" "エ"

file5.r

withr::with_collate("C", sort(d$kana))

#> [1] "あ" "う" "お" "イ" "エ"

file6.r

stringi::stri_sort(d$kana, locale = "C")

#> [1] "あ" "イ" "う" "エ" "お"

file7.r

## 通常の空気読んだソート
stringi::stri_sort(d$letter, locale = "en_EN")

#> [1] "A" "b" "C" "e" "Z"

file8.r

## locale = "C"っぽさがあるソート
stringi::stri_sort(d$letter, locale = "C")

#> [1] "A" "C" "Z" "b" "e"

file9.r

## locale="en"のデフォルトのソートは小文字が前に出る
str <- c("a", "A", "a", "A")
stringi::stri_sort(str, locale = "en")

#> [1] "a" "a" "A" "A"