Convert array to single object if array is a single object

Question

Really simple question.

Is there a method to do the following?

["a"] => "a"
[1] => 1
[1,"a"] => [1, "a"]

i.e. if an array is a single object, return the object, otherwise return the array. Without doing something ugly like

array.length == 1 ? array[0] : array

Not to my knowledge -- but why would you want to do this? Whatever you're passing this data to should respond to either an array or a string, popping out a single value if it's alone means that your code further along has to know how to deal with both arrays and strings, rather than just relying n always having an array. — Mike Manfrin
– Mike Manfrin, Commented Mar 10, 2016 at 20:33
Possible duplicate of Is there a ruby idiom for returning the first array element, if only one exists? — ndnenkov
– ndnenkov, Commented Mar 10, 2016 at 20:38
To clarfiy, one of the reasons I want to do it is that I want to replicate the functionality of the .pluck method in rails 4 for rails 3. Pluck in rails 4 returns either single objects, if only one column is plucked, or an array of multiple objects, if multiple objects are plucked. — Carpela
– Carpela, Commented Mar 11, 2016 at 12:04
In terms of the duplicate. You probably have a point there. However, I'm not sure that the question title is easy enough to find in order to stop people being stuck. (Hence I didn't find it...) Not sure if I accept the duplicate in that case... — Carpela
– Carpela, Commented Mar 11, 2016 at 12:05

djaszczurowski · Accepted Answer · 2016-03-10 20:36:49Z

1

basically you should stick to what you wrote - it's simple and does what it should.

of course you may always monkey patch the Array definition... (unrecommended, but it does what you expect)

class Array
  def first_or_array
    length > 1 ? self : self[0]
  end
end

[1].first_or_array # 1
[1, 2].first_or_array # [1, 2]

answered Mar 10, 2016 at 20:36

djaszczurowski

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2 Comments

Edvaldo Silva de Almeida Jr Over a year ago

Exactly this! I was going to post the same. But I'd add something. This not excludes the possibility of having something like [[1,2]] and then [[1,2]].first_of_array = [1,2], still an array, although the content is a single object (another array). This would have to be something recursive, if the goal is to reach a single object.

sawa Over a year ago

If you can't do any better than the OP, you should just suggest the OP to go with that way. This does need to be an answer. It could just be a comment.

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