How to tell lapply to ignore an error and process the next thing in the list?

Question

I have an example function below that reads in a date as a string and returns it as a date object. If it reads a string that it cannot convert to a date, it returns an erro

Answer 1

Use a tryCatch expression around the function that can throw the error message:

testFunction <- function (date_in) {
  return(tryCatch(as.Date(date_in), error=function(e) NULL))
}

The nice thing about the tryCatch function is that you can decide what to do in the case of an error (in this case, return NULL).

> lapply(dates2, testFunction)
[[1]]
[1] "2010-04-06"

[[2]]
NULL

[[3]]
[1] "2010-04-08"