订单如何运作？

Question

这是一个非常令人尴尬的问题，但我无法理解以下结果：

> order(c(3,1,2))
[1] 2 3 1

那么，它是说有序序列是2, 3, 1？怎么样？

Answer 1

> a <- c(30,10,20)     # sample data
> sort(a)              # sort returns your vector sorted
[1] 10 20 33
> order(a)             # order returns the *indices* in the sorted vector
[1] 2 3 1
> a[order(a)]          # so if you select your numbers with those indices
[1] 10 20 30           # you get your vector sorted