From: "alexeymuranov (Alexey Muranov)" <redmine@...>
Date: 2013-09-02T18:52:49+09:00
Subject: [ruby-core:56966] [ruby-trunk - Feature #7292] Enumerable#to_h


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


I understand that using #to_a or #first and #last directly would give an unexpected result when calling #to_h on a collection of strings, for example, but one is not supposed to call #to_h on a collection of strings, or #to_h should be preceded with #select.

The two #next and one #raise look a bit like a defensive programming to me, and could cause an unnecessary slowdown.  Wouldn't it be better to let the user decide when to precede #to_h with #select?
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Feature #7292: Enumerable#to_h
https://bugs.ruby-lang.org/issues/7292#change-41540

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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