order() and sort()

• order() returns a vector that lists indices corresponding to the values of ‘x’

x <- c(10, 20, 30, 50, 40)
order(x)

## [1] 1 2 3 5 4

• sort() returns the original vector, in ascending order

sort(x)

## [1] 10 20 30 40 50

• sort(x) is equivalent to x[order(x)]

all.equal(sort(x), x[order(x)])

## [1] TRUE