From: "nathan.f77 (Nathan Broadbent)" <nathan.f77@...>
Date: 2012-11-07T04:56:23+09:00
Subject: [ruby-core:48993] [ruby-trunk - Feature #7292] Enumerable#to_h


Issue #7292 has been updated by nathan.f77 (Nathan Broadbent).


I agree, Enumerable#to_h would make sense and be quite useful.

(1..3).to_h would be a special case for the Range class, because [1, 2, 3].to_h should raise an exception.

Here's an example in Ruby:

module Enumerable
  def to_h
    hash = {}
    each_with_index do |el, i|
      raise TypeError, "(at index #{i}) Element is not an Array" unless Array === el
      raise IndexError, "(at index #{i}) Array has more than 2 elements" if el.size > 2
      hash[el[0]] = el[1]
    end
    hash
  end
end
----------------------------------------
Feature #7292: Enumerable#to_h
https://bugs.ruby-lang.org/issues/7292#change-32514

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


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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