Parsing dates in R from strings with multiple formats

Question

I have a tibble in R with about 2,000 rows. It was imported from Excel using read_excel. One of the fields is a date field: dob. It imported as a string, and has dates in three

Answer 1

We create a logical index after the first run based on the NA values and use that to index for the second run

i1 <- is.na(dob_fixed)
dob_fixed[i1] <- as.Date(as.integer(dob[i1]), origin = "1899-12-30")