Convert string to date, format: “dd.mm.yyyy”

Question

D <- \"06.12.1948\"                 # which is dd.mm.yyyy
as.Date(D, \"%d.%m.%y\")            # convert to date
[1] \"2019-12-06\"                  # ????    
         


        

Answer 1

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’.