check whether all elements of a list are in equal in R

Question

I have a list of several vectors. I would like to check whether all vectors in the list are equal. There\'s identical which only works for pairwise comparison.

Answer 1

How about

allSame <- function(x) length(unique(x)) == 1

allSame(test_true)
# [1] TRUE
allSame(test_false)
# [1] FALSE

As @JoshuaUlrich pointed out below, unique may be slow on lists. Also, identical and unique may use different criteria. Reduce is a function I recently learned about for extending pairwise operations:

identicalValue <- function(x,y) if (identical(x,y)) x else FALSE
Reduce(identicalValue,test_true)
# [1] 1 2 3
Reduce(identicalValue,test_false)
# [1] FALSE

This inefficiently continues making comparisons after finding one non-match. My crude solution to that would be to write else break instead of else FALSE, throwing an error.