Using weekdays with any locale under Windows

The system of naming locales is OS-specific. I recommend you to read the locales from R Installation and Administration manual for a complete explanation.

under windows :

The list of supported language is listed MSDN Language Strings. And surprisingly there is not Arabic language there. The "Language string" column contains the legal input for setting locale in R and even in the list contry /regions strings there no country spoken arabic there.

Of course you can change your locale global settings( panel setting --> region --> ..) but this will change it globally and it is not sure to get the right output without encoding problem.

under linux(ubuntu in my case):

Arabic is generally not supported by default, but is easy to set it using locale.

 locale -a                     ## to list all already supported language sudo locale-gen ar_QA.UTF-8   ## install it in case does not exist

under RStudio now :

 Sys.setlocale('LC_TIME','ar_QA.UTF-8')[1] "ar_QA.UTF-8"> format(Sys.Date(),'%A')[1] "الثلاثاء

Note also that under R console the printing is not as pretty as in R studio because it is written from left to right not from right to left.

The RStudio/Architect problem

This can be solved, slightly messily, by explicitly changing the encoding of the weekdays string to UTF-8.

current_codepage <- as.character(l10n_info()$codepage)iconv(weekdays(Sys.Date()), from = current_codepage, to = "utf8")

Note that codepages only exist on Windows; l10n_info()$codepage is NULL on Linux.

The LC_TIME problem

It turns out that under Windows you have to set both the LC_CTYPE and LC_TIME locale categories, and you have to set LC_CTYPE before LC_TIME, or it won't work.

In the end, we need different implementations for different OSes.

Windows version:

get_today_windows <- function(locale = NULL){  if(!is.null(locale))  {    lc_ctype <- Sys.getlocale("LC_CTYPE")    lc_time <- Sys.getlocale("LC_TIME")    on.exit(Sys.setlocale("LC_CTYPE", lc_ctype))    on.exit(Sys.setlocale("LC_TIME", lc_time), add = TRUE)    Sys.setlocale("LC_CTYPE", locale)    Sys.setlocale("LC_TIME", locale)  }  today <- weekdays(Sys.Date())  current_codepage <- as.character(l10n_info()$codepage)  iconv(today, from = current_codepage, to = "utf8")}get_today_windows() ## [1] "Tuesday"get_today_windows("French_France")## [1] "mardi"get_today_windows("Arabic_Qatar")## [1] "الثلاثاء"get_today_windows("Serbian (Cyrillic)") ## [1] "уторак"get_today_windows("Chinese (Traditional)_Taiwan") ## [1] "星期二"

Linux version:

get_today_linux <- function(locale = NULL){  if(!is.null(locale))  {    lc_time <- Sys.getlocale("LC_TIME")    on.exit(Sys.setlocale("LC_TIME", lc_time), add = TRUE)    Sys.setlocale("LC_TIME", locale)  }  weekdays(Sys.Date())}get_today_linux() ## [1] "Tuesday"get_today_linux("fr_FR.utf8")## [1] "mardi"get_today_linux("ar_QA.utf8")## [1] "الثلاثاء"get_today_linux("sr_RS.utf8") ## [1] "уторак"get_today_linux("zh_TW.utf8") ## [1] "週二"

Enforcing the .utf8 encoding in the locale seems important get_today_linux("zh_TW") doesn't display properly.