as.Dateの使い方

You can use the as.Date( ) function to convert character data to dates. The format is as.Date(x, “format”), where x is the character data and format gives the appropriate format.

# convert date info in format 'mm/dd/yyyy'
strDates <- c("01/05/1965", "08/16/1975")
dates <- as.Date(strDates, "%m/%d/%Y")