How to convert character and dates to dates?

问题

My data comes from excel. The dates are in dd/mm/yyyy format:

certificado$fecha <- c("22/02/2019", "43679", "22/02/2019", "22/01/2019", "28/10/2019", 
"18/09/2019")

However, R is reading some dates as mm/dd/yyyy. My code is supposed to convert all of them to an specific format.

certificados$Fecha <- as.Date(certificados$Fecha,format = "%d/%m/%Y")

But im getting NAs due to date format issues.

回答1:

If you cannot fix this at the source, this code finds both formats:

vec <- c("22/02/2019", "43679", "22/02/2019", "22/01/2019", "28/10/2019", "18/09/2019")
out <- as.Date(vec, format = "%d/%m/%Y")
out
# [1] "2019-02-22" NA           "2019-02-22" "2019-01-22" "2019-10-28" "2019-09-18"

isna <- is.na(out)
out[isna] <- as.Date(as.integer(vec[isna]), origin = "1900-01-01")
out
# [1] "2019-02-22" "2019-08-04" "2019-02-22" "2019-01-22" "2019-10-28" "2019-09-18"

来源：https://stackoverflow.com/questions/58880848/how-to-convert-character-and-dates-to-dates