Ruby 'Range.last' does not give the last value. Why?

Question

When using the triple dot notation in a ruby Range object, I get this:

(0...5).each{|n| p n}
0
1
2
3
4

When I use the \'last\' method I get

Answer 1

As Stefan has answered your observed behavior is expected and documented.

If you want to obtain the last element which would be enumerated by the range without having to enumerate the whole range, you could use Enumerable#reverse_each

irb> (0...5).reverse_each.first
=> 4

Answer 2

This is by design. The Ruby 2.0 documentation is more specific:

Note that with no arguments last will return the object that defines the end of the range even if exclude_end? is true.

(10..20).last      #=> 20
(10...20).last     #=> 20
(10..20).last(3)   #=> [18, 19, 20]
(10...20).last(3)  #=> [17, 18, 19]