From: "marcandre (Marc-Andre Lafortune)" <ruby-core@...>
Date: 2012-03-26T22:46:03+09:00
Subject: [ruby-core:43684] [ruby-trunk - Feature #6203] Array#values_at does not handle ranges with end index past the end of the array


Issue #6203 has been updated by marcandre (Marc-Andre Lafortune).


Hi,

nobu (Nobuyoshi Nakada) wrote:
> It's definitely not a bug.

It's not?
How do you explain:

    [1, 2, 3].values_at(2...42) # => [3]
    [1, 2, 3].values_at(2..41)  # => [3, nil]

I feel that both must return the same result.
Moreover, the only acceptable results are either [3] or [3, nil, nil, ... nil]

----------------------------------------
Feature #6203: Array#values_at does not handle ranges with end index past the end of the array
https://bugs.ruby-lang.org/issues/6203#change-25181

Author: ferrous26 (Mark Rada)
Status: Open
Priority: Normal
Assignee: 
Category: core
Target version: 1.9.3


=begin
When I use Array#values_at I expect that it would be the same as successive calls to (({Array#[]})).

There is one case where this does not hold:

    a = [0,1,2,3,4,5]
    a[4..6] # => [4, 5]
    a.values_at(4..6) # => [4,5,nil]

I think this is an inconsistency in the design of (({Array#values_at})). We can look at a more extreme case:

    a[4..100] # => [4, 5]
    a.values_at 4..100 # => [4, 5, nil]

And now it doesn't make any sense.

I think the best solution would be to make (({Array#values_at})) be equivalent to successive calls to (({Array#[]})). I have patched (({rb_range_beg_len()})) to handle the extra case and opened a pull request on github.
=end


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