How to get the differences of two set in R?

Question

Suppose:

x <- c(2,-5)
y <- c(1,2,3)

How can I get :

z = c(2-1, 2-2, 2-3, -5-1, -5-2, -5-3) = c(1, 0, -1, -6, -7, -8)

Answer 1

Using outer:

> as.vector(outer(x, y, '-'))
# [1]  1 -6  0 -7 -1 -8

And if you want the other way:

> as.vector(t(outer(x, y, '-')))
# [1]  1  0 -1 -6 -7 -8

Answer 2

You can use rep as follows:

rep(x, each = length(y)) - y
# [1]  1  0 -1 -6 -7 -8