Test if an object is not sorted (in increasing order), without the cost of sorting it.
is.unsorted(x, na.rm = FALSE, strictly = FALSE)an R object with a class or a numeric, complex, character, logical or raw vector.
logical. Should missing values be removed before checking?
logical indicating if the check should be for strictly increasing values.
A length-one logical value. All objects of length 0 or 1 are sorted.
Otherwise, the result will be NA except for atomic vectors and
objects with an S3 class (where the >= or > method is
used to compare x[i] with x[i-1] for i in
2:length(x)) or with an S4 class where you have to provide a
method for is.unsorted().