You can get full month name in the current locale with:
format(ISOdate(2000, 1:12, 1), "%B")
#months(ISOdate(2000, 1:12, 1)) #Alternative
and abbreviated month name in the current locale with:
format(ISOdate(2000, 1:12, 1), "%b")
#months(ISOdate(2000, 1:12, 1), TRUE) #Alternative
To change the locale have a look at How to change the locale of R? in case Sys.setlocale("LC_TIME", "de_DE.UTF-8")
is not working.
And to make the conversion local short to local long:
loc2loc <- setNames(format(ISOdate(2000, 1:12, 1), "%B"), format(ISOdate(2000, 1:12, 1), "%b"))
loc2loc["Jan"]
and local short to English long:
loc2eng <- setNames(month.name, format(ISOdate(2000, 1:12, 1), "%b"))
loc2eng["Jan"]
Or without using locales - hard coded:
de2de <- setNames(c("Januar", "Februar", "März", "April", "Mai", "Juni", "Juli"
, "August", "September", "Oktober", "November", "Dezember"), c("Jan", "Feb"
, "Mär", "Apr", "Mai", "Jun", "Jul", "Aug", "Sep", "Okt", "Nov", "Dez"))
de2de[c("Jan", "Feb", "Mär", "Apr", "Mai")]
# Jan Feb Mär Apr Mai
# "Januar" "Februar" "März" "April" "Mai"