The order function in R

Question

I don’t understand what happens. Watch

> x<-c(-2,4,-6,5,9,7)

> x

[1] -2  4 -6  5  9  7

> order(x)

[1] 3 1 2 4 6 5

I don’t understand why vector x is not ordered. Note, when I give order(x) add the 7

And in this case? Supposedly you wouldn’t have to give me vector x ordered downwards?

> order(x, decreasing=TRUE)

[1] 5 6 4 2 1 3

What a strange thing! Help please

Answer 1

The function order does not return the ordered original vector, but returns a vector with the positions so that x stay in ascending order.

Thus, to get back the vectorx ordered, you have to put x[order(x)]:

x[order(x)]
[1] -6 -2  4  5  7  9

Or in descending order:

x[order(x, decreasing=TRUE)]
[1]  9  7  5  4 -2 -6

If you want to do this directly, you can use the function sort, which already returns to you the ordered vector instead of the positions:

sort(x)
[1] -6 -2  4  5  7  9

Or:

sort(x, decreasing=TRUE)
[1]  9  7  5  4 -2 -6