[ruby-core:56969] [ruby-trunk - Feature #7292] Enumerable#to_h

Issue #7292 has been updated by alexeymuranov (Alexey Muranov).


Another alternative: since two-element arrays are used here as ordered pairs, maybe the Array class can be extended with #key and #value methods, which would be identical to #first and #last respectively on two-element arrays, and raise errors otherwise. Then #to_h can be implemented as

module Enumerable
  def to_h
    h = {}
    each_entry do |pair|
      h[pair.key] = pair.value
    end
    h
  end
end

It would be then applicable to any collection of objects that respond to #key and #value.

If #key and #value seem to be overused as names, maybe better names can be found?

So, the idea is to extend Array simultaneously with Enumerable.
----------------------------------------
Feature #7292: Enumerable#to_h
https://bugs.ruby-lang.org/issues/7292#change-41544

Author: marcandre (Marc-Andre Lafortune)
Status: Open
Priority: Normal
Assignee: marcandre (Marc-Andre Lafortune)
Category: core
Target version: next minor


Now that #to_h is the official method for explicit conversion to Hash, we should also add

	Enumerable#to_h: Returns a hash for the yielded key-value pairs.

	  [[:name, 'Joe Smith'], [:age, 42]].to_h # => {name: 'Joe Smith', age: 42}


With the Ruby tradition of succint documentation I suggest the documentation talk about key-value pairs and there is no need to be explicit about the uninteresting cases like:

    (1..3).to_h           # => {1 => nil, 2 => nil, 3 => nil}
    [[1, 2], [1, 3]].to_h # => {1 => 3}
    [[1, 2], []].to_h     # => {1 => 2, nil => nil}

I see some reactions of people reading about the upcoming 2.0 release like this one:
http://globaldev.co.uk/2012/11/ruby-2-0-0-preview-features/#dsq-comment-body-700242476



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