[R] if one of 4 conditions is not satisfied

[Marc Schwartz]

on 07/01/2008 07:40 AM mysimbaa wrote:
> I'm trying to do realize the following:
> I have 4 condtions.
> If all conditions are satisfied I will paste("PASS")
> If any of these is not satisfied I will paste("FAIL"). But I have to paste
> the corresponding failure.
> 
> ifelse is a good solution but for a 2 conditions. Maybe switch or something
> like this.
> 
> Does anyone have an idea how to do?
> 
> Thanks in advance.
> Adel

An easy way would be to have your condition results, which are 
presumably TRUE/FALSE, in a vector such as:

   Cond <- c(TRUE, FALSE, FALSE, TRUE)

Then you could use all() to check to see if they are 'all' TRUE:

   > all(Cond)
   [1] FALSE

Then use which() to get the index of the FALSE elements:

   > which(!Cond)
   [1] 2 3

If you have your test labels in a character vector, such as:

   Cond.Vec <- c("Cond 1", "Cond 2", "Cond 3", "Cond 4")

You could then use:

if (all(Cond)) {
   Out <- "PASS"
} else {
   Out <- paste("FAIL:", paste(Cond.Vec[which(!Cond)],
                         collapse = " & "))
}


 > Out
[1] "FAIL: Cond 2 & Cond 3"


See ?all and ?which

HTH,

Marc Schwartz