Question

Are there ruby equivalents to the lisp car, cdr, and cons functions? For those unfamiliar with lisp, here’s what I want from ruby:

[1,2,3].car   => 1
[1,2,3].cdr   => [2,3]
[2,3].cons(1) => [1,2,3]

(in lisp):

(car '(1 2 3))  => 1
(cdr '(1 2 3))  => (2 3)
(cons 1 '(2 3)) => (1 2 3)

Answer 1

Ruby arrays are not implemented as singly-linked lists, so it is not as useful to have car and cdr and stuff.

If you really wanted, you could do

[1,2,3][0]      => 1
[1,2,3].first   => 1
[1,2,3][1..-1]  => [2,3]
[1] + [2,3]     => [1,2,3]