Converting ruby array to array of consecutive pairs

Question

What is the easiest way to convert a ruby array to an array of consecutive pairs of its elements?

I mean:

x = [:a, :b, :c, :d]

Expected result:

y #=> [[:a, :b], [:c, :d]]

score 89 · Accepted Answer · edited Jul 03 '17 at 06:56

89

y = x.each_slice(2).to_a
#=> [[:a, :b], [:c, :d]]

[0, 1, 2, 3, 4, 5].each_slice(2).to_a
#=> [[0, 1], [2, 3], [4, 5]]

edited Jul 03 '17 at 06:56

Stefan

answered Aug 13 '10 at 14:31

deinst

score 4 · Answer 2 · answered Aug 13 '10 at 14:30

4

Hash[*[:a, :b, :c, :d]].to_a

answered Aug 13 '10 at 14:30

Daniel O'Hara

Clever, but it does not preserve the order. – Josh Lee Aug 13 '10 at 14:34
It does (at least in Ruby 1.9.2dev). – Daniel O'Hara Aug 13 '10 at 14:42
3

It also fails if there happens to be a duplicate key. `Hash[*[:a,:b,:c,:d,:a,:e]]` – Chubas Aug 14 '10 at 01:25
Also fails if length of array is not divisible by 2. - `Hash[*[1,2,3]].to_a` fails `[1,2,3].each_slice(2).to_a` doesn't – PL J Oct 20 '15 at 13:01

2 Answers2