commandline session
> c(1,2,3,4,5)
[1] 1 2 3 4 5
> x
[1] 1
> c
function (..., recursive = FALSE) .Primitive("c")
> x x
[1] 22
> ' x
[1] 35
> w w
[1] 1 2 3 4 5
> w[3]
[1] 3
> w[0]
numeric(0)
> w[1]
[1] 1
> w[6]
[1] NA
> z w
[1] 1 2 3 4 5
> z
[1] 10 20 30 14 50
> plot(w,z)
>
