How to iterate through an array of hashes sorting the keys in Ruby

Question

I have an array of hashes like this:

items = [{"id"=>"123", "code"=>"abc","name"=>"test", "type"=>["good"]},
   {"id"=>"555", "code"=>"ddd","name"=>"foo", "type"=>["better"]},
   {"id"=>"098", "code"=>"zyx","name"=>"bar", "type"=>["best"]}]

I am trying to sort each hash within the array by the key.

I tried this:

items.each { |item| item = item.sort.to_h }

It returns the same result:

 [{"id"=>"123", "code"=>"abc", "name"=>"test", "type"=>["good"]},
 {"id"=>"555", "code"=>"ddd", "name"=>"foo", "type"=>["better"]},
 {"id"=>"098", "code"=>"zyx", "name"=>"bar", "type"=>["best"]}]

but when I try this:

items[0].sort.to_h

this is the result:

 {"code"=>"abc", "id"=>"123", "name"=>"test", "type"=>["good"]}

So it looks like when I call the individual elements within items using items[x] where x is an index value within the array, it sort it. But I need a solution to iterate through each element doing that and saving the sort.

Any thoughts?

As @Sagar said use `items.map { |item| item = item.sort.to_h }` — Bharath M Shetty, Dec 10 '17 at 03:48
@SagarPandya I wish you posted the answer. what you suggested was exactly correct. — adbarads, Dec 10 '17 at 04:54
@Dark, thanks you provided more details to the exact same answer. it worked. the item = that i did was not necessary. I could have just done this items.map { |item| item.sort.to_h } — adbarads, Dec 10 '17 at 04:54
Possible duplicate of [How to sort a Ruby Hash alphabetically by keys](https://stackoverflow.com/questions/27384967/how-to-sort-a-ruby-hash-alphabetically-by-keys) — crazy_phage, Dec 11 '17 at 08:48

score 1 · Answer 1 · answered Dec 10 '17 at 04:55

1

I solved it with this:

items.map { |item| item.sort.to_h }

Thanks @SagarPandya and @Dark

answered Dec 10 '17 at 04:55

adbarads

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`items.map(&:sort).map(&:to_h)` – Aleksei Matiushkin Dec 10 '17 at 05:39

score 0 · Answer 2 · answered Dec 10 '17 at 07:02

If, as in the example, all the hashes have the same keys, it would be faster to perform a single sort on the keys.

sorted_keys = items.first.keys.sort
  #=> ["code", "id", "name", "type"]
items.map { |item| sorted_keys.each_with_object({}) { |k,h| h[k] = item[k] } }
  #=> [{"code"=>"abc", "id"=>"123", "name"=>"test", "type"=>["good"]},
  #    {"code"=>"ddd", "id"=>"555", "name"=>"foo", "type"=>["better"]},
  #    {"code"=>"zyx", "id"=>"098", "name"=>"bar", "type"=>["best"]}]

The last line could alternatively be written

items.map { |item| sorted_keys.zip(item.values_at(*sorted_keys)).to_h }

How to iterate through an array of hashes sorting the keys in Ruby

2 Answers2