Ruby array each_slice_with_index?

Question

If I have arr = [1, 2, 3, 4] I know I can do the following...

> arr.each_slice(2) { |a, b| puts \"#{a}, #{b}\" }
1, 2
3, 4

...A

Answer 1

In 1.9 a lot of methods return an enumerator if no block is provided. You can call another method on the enumerator.

arr = [1, 2, 3, 4, 5, 6, 7, 8] 
arr.each_with_index.each_slice(2){|(a,i), (b,j)| puts "#{i} - #{a}, #{b}"}

(Variation on @sepp2k). Result:

0 - 1, 2
2 - 3, 4
4 - 5, 6
6 - 7, 8