Dear all,

As a novice user of R I ran into a problem that's quite hard for me to
resolve. I have a database containing data of a clinical trial in which
patients are included that survived or died:

x <- matrix(data=c(1:5,0, "1/1/2012 00:00:00",0,0,"1/7/2012 00:00:00"),
nrow=5, ncol=2, dimnames= list(NULL,c("ID", "dateofdeath")))

My file is a .csv so I don't have a problem with the brackets, don't know
how to show you the idea without the brackets...

I want to be able to do calculations with the values in the column
x$dateofdeath so use the chron-package for this:

library(chron)
x$dateofdeath<- as.character(x$dateofdeath)
dateofdeath1 <- t(as.data.frame(strsplit(x$dateofdeath,' ')))
row.names(dateofdeath1) <- NULL
x$dateofdeath<-
chron(dates=dateofdeath1[,1],times=dateofdeath1[,2],format=c('d-m-y','h:m:s'))

When I run this script the database looks like this:

> x
  ID         dateofdeath
1  1             (NA NA)
2  2 (01-01-12 00:00:00)
3  3             (NA NA)
4  4             (NA NA)
5  5 (01-07-12 00:00:00)

The times are how I want them to be, the zero's on the other hand should
stay that way. In other words: how can I make the database look like this:

> x
  ID         dateofdeath
1  1             0
2  2 (01-01-12 00:00:00)
3  3             0
4  4             0
5  5 (01-07-12 00:00:00)

I already tried replacing the NA's with 0 which gives me 1-1-1970 (the
default date by chron) and making a subset and only replacing values that
are not equal to zero doesn't work either:

d <- x
## above coding for chron with x replaced with d ##
mat <- match(x$ID, d$ID)
x$dateofdeath <- d$dateofdeath[mat]


Does anybody know how to resolve this issue?
Thanks in advance!
Cheers, Rick Admiraal

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