Using identical() in R with multiple vectors

Question

Suppose that I have five vectors:

A<-1:10 B<-1:10 C<-1:10 D<-1:10 E<-1:12 

I could test two at a time using identical( ).

identical(A,C) 

But I want to test ALL of them at once to see if ANY is different from the others. Is there an easy way to do this?

Answer 1

I would just pick one, say A, and do all pair-wise comparisons with it.

all(sapply(list(B, C, D, E), FUN = identical, A)) # [1]  FALSE 

Remove the all() to see the not identical one(s)

sapply(list(B, C, D, E), FUN = identical, A) # [1]  TRUE  TRUE  TRUE FALSE 

identical ought to be transitive, so if A is identical to C and to D, then C should be identical to D.

(Thanks to @docendo discimus for simplified syntax.)

Answer 2

First thought is to do unique on a list of the vectors and check the length. If there are two or more vectors that are different, then the length of the resulting list will be greater than 1.

length(unique(list(A,B,C,D))) == 1 [1] TRUE  length(unique(list(A,B,C,D,E))) == 1 [1] FALSE