filtering - find-if commands

[frz]

Hi, Could someone please tell me how to do this simple search. I don't know much programming and this is beyond me. But I think it should be a simple find-if loop?
Thanks so much. File below has my query


# need to perform
# if for each value j (X, Y, Z) in column2, value i in column1 = A and B and C and D, then output value j
# so in this example, I should only get 'X' as the output
# as only X has rows with all four value i (A and B and C and D)

A X
A X
B X
C X
D X
D X
D X
A Y
A Y
B Y
A Z
B Z
C Z
C Z
C Z
C Z
C Z
C Z
C Z

[dpryan]

Saving that file as "foo.txt", one could just use R:

#Read in the file
d <- read.table("foo.txt", sep=" ")
#Split it according to the second column
dl <- split(d, d$V2)
#Create a function to return TRUE/FALSE
foo <- function(x) {
     if(length(unique(x$V1)) != 4) {
         FALSE
     } else if(!all(c("A","B","C","D") %in% unique(x$V1))) {
         FALSE
     } else {
         TRUE
    }
}
#Run things
sapply(dl,foo)

The output is:

    X     Y     Z 
 TRUE FALSE FALSE

[frz]

Hi dpryan,

This was really useful, thanks! I tried it on my actual data which is a bit more complex than the example above. I had to switch the %in% operator to come after the ("A","B',"C","D") instead of before and then it ran fine

Thanks again!!

[dpryan]

True, I missed that. I updated my reply to incorporate that fix, should someone need it later.