| unique {base} | R Documentation |
Extract Unique Elements
Description
unique returns a vector like x but with duplicate
elements removed. If an element is equal to one with a smaller index,
it is removed.
Usage
unique(x)
Arguments
x |
an atomic vector |
See Also
duplicated which gives the indices of duplicated elements.
Examples
unique(c(3:5, 11:8, 8 + 0:5))
length(unique(sample(100,100,replace=T)))# ~= 100(1 - 1/e) = 63.21
my.unique <- function(x) x[!duplicated(x)]
for(i in 1:4)
{ x <- rpois(100, pi); stopifnot(unique(x) == my.unique(x)) }