[R] remove

[Val]

Hi all,
I have  a date  issue and would appreciate any help.

I am reading a field data and  n one of the columns I am expecting a
date but has  non date  values  such as  character and  empty. space.
Here is a sample of my data.

KL <- read.table(header=TRUE, text='ID date
711 Dead
712 Uknown
713 20-11-08
714 11-28-07
301
302 09-02-02
303 09-21-02',stringsAsFactors = FALSE, fill =T)

str(KL)
data.frame': 7 obs. of  2 variables:
 $ ID  : int  711 712 713 714 301 302 303
 $ date: chr  "Dead" "Uknown" "20-11-08" "11-28-07" .

I wanted to convert the date column as follows.
if (max(unique(nchar(as.character(KL$date))))==10) {
  KL$date <- as.Date(KL$date,"%m/%d/%Y")
}
but not working.


How  could I to remove the corresponding entire row. that do not have
a date format and do the operation?
thank you in advance