D <- "06.12.1948" # which is dd.mm.yyyy
as.Date(D, "%d.%m.%y") # convert to date
[1] "2019-12-06" # ????
what is it that I am missing?
Sys.getlocale(category = "LC_ALL") [1] "LC_COLLATE=German_Austria.1252;LC_CTYPE=German_Austria.1252;LC_MONETARY=German_Austria.1252;LC_NUMERIC=C;LC_TIME=German_Austria.1252"
The format is case-sensitive ("%y" is ambiguous and system dependent, I believe):
as.Date(D, "%d.%m.%Y")
[1] "1948-12-06"
The help topic ?strptime
has details:
‘%y’ Year without century (00-99). On input, values 00 to 68 are
prefixed by 20 and 69 to 99 by 19 - that is the behaviour
specified by the 2004 and 2008 POSIX standards, but they do
also say ‘it is expected that in a future version the default
century inferred from a 2-digit year will change’.
To expand on this,
"%y"
is for 2-digit years, so it's read in the "19" in 1948. You want"%Y"
.