Using Ruby 2.4. I have an array of strings ...
["a", "b", "c"]
How do I take the above and convert each element into its own array of one element? So I would want the result of such an operation to be
[["a"], ["b"], ["c"]]
?
4 Answers
You can use zip:
["a", "b", "c"].zip #=> [["a"], ["b"], ["c"]]
2 Comments
aaronkelton
Thanks, I was previously iterating over each id passing to a Sidekiq job. I saw the api for
perform_bulk and needed to get each id into its own array.
Sagar Pandya
@aaronkelton that's nice to know this answer has helped in an actual practical situation; the Ruby language is great!
a.map { |s| Array(s) }
or
a.map { |s| [s] }
3 Comments
Aleksei Matiushkin
["a", "b", "c"].map &Kernel.method(:Array)
mu is too short
@mudasobwa Or since
Kernel is mixed into everything so that we can pretend to have functions: ["a", "b", "c"].map &method(:Array)
Cary Swoveland
Unexciting, but 99% of Rubiests would elect your #2.
Also, you can use combination or permutation methods, it also provide little bit more functionality
a.combination(1).to_a
#=> [['a'], ['b'], ['c']]
a.combination(2).to_a
#=> [["a", "b"], ["a", "c"], ["b", "c"]]
a.permutation(1).to_a
#=> [['a'], ['b'], ['c']]
a.permutation(2).to_a
#=> [["a", "b"], ["a", "c"], ["b", "a"], ["b", "c"], ["c", "a"], ["c", "b"]]
answered Feb 13, 2017 at 19:02
Oleksandr Holubenko
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Comments
Interesting that you can use Array#zip to do this. I did not realize #zip worked at all without an argument. Ruby always has a new trick up its sleeve.
Not that this is any better, but it might be a bit more intuitive:
>> ["a", "b", "c"].each_slice(1).to_a
=> [["a"], ["b"], ["c"]]
["a", "b", "c"].each_cons(1).to_av#=> [["a"], ["b"], ["c"]]is yet another way.