See ?tryCatch. Example: Function returning NULL if cancelled:
fileChoose <- function(...) { pathname <- NULL; tryCatch({ pathname <- file.choose(); }, error = function(ex) { }) pathname; } /Henrik On 6/6/07, Ben Tupper <[EMAIL PROTECTED]> wrote: > Hello, > > > I have a file reading function that prompts the user with a file dialog > if a filename is not provided in the argument list. It is desirable to > return gracefully if the user selects "Cancel", but file.choose() throws > an error instead of returning something like a character. > > > file.choose() > [1] "/Users/ben/ben_idl.pref" > > > file.choose() > Error in file.choose() : file choice cancelled > > I naively planned to use nchar() to test the length, assuming > cancellation would return a zero-length character. That appears to be > out of the question. Are there other options available in the base package? > > Thanks! > Ben > > ______________________________________________ > R-help@stat.math.ethz.ch mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. > ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.