How can I get the next n number of elements using a Ruby enumerator?

Question

I am trying to get the next n number of elements using a Ruby enumerator, with this:

a = [1, 2, 3, 4, 5, 6]
enum = a.each
enum.next(2) # expecting [1, 2]
enum.next(2) # expecting [3, 4]

But #next does not support that. Is there another way that I can do that? Or shall I do?

What is the correct Ruby way to do that?

Wand Maker · Accepted Answer · 2016-04-15T10:51:09.153

5

You can use take method

enum.take(2)

If you need slices of two elements, you could do:

e = enum.each_slice(2)
p e.next
#=> [1, 2]
p e.next
#=> [3, 4]

edited Apr 15 '16 at 10:51

answered Apr 15 '16 at 10:46

Wand Maker

1

But this one always return the first 2. Am I wrong? – p.matsinopoulos Apr 15 '16 at 10:47
@p.matsinopoulos What is the exact requirement? Do you wish to retrieve every 2 elements or retrieve arbitrary number of elements from the point you last left the enum at? – Wand Maker Apr 15 '16 at 10:49

score 1 · Answer 2 · answered Apr 15 '16 at 10:53

1

a = [1, 2, 3, 4, 5, 6]
enum = a.dup
enum.shift(2) # => [1, 2]
enum.shift(2) # => [3, 4]

answered Apr 15 '16 at 10:53

sawa

2 Answers2