Forum: Ruby-core Inconsistent Array.slice()

Issue #4541 has been updated by stomar (Marcus Stollsteimer).


alexeymuranov (Alexey Muranov) wrote:
> I hope this does not mean that the specification is now based on the 
implementation :).

I just wanted to point out that the docs now reflect that it is intended 
behavior and not a bug.
Nothing more, nothing less.
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Feature #4541: Inconsistent Array.slice()
https://bugs.ruby-lang.org/issues/4541#change-34695

Author: kbl (Marcin Pietraszek)
Status: Assigned
Priority: Normal
Assignee: matz (Yukihiro Matsumoto)
Category: core
Target version: next minor


=begin
Array slice/[] method is a bit inconsistent. Is it just poorly 
documented "feature" or a bug? In API doc I can't find this behaviour 
mentioned as a "special case".

 def test_array_slice
    array = ['a', 'b', 'c']
    assert_equal nil, array[3]
    assert_eaual nil, array[4]

    assert_eaual [], array[3, 0] #
    assert_equal nil, array[4, 0] # [] expected (or both nils in 
array[3, 0] and array[4, 0])

    assert_equal ['c'], array[2..2]
    assert_equal [], array[3..3] #
    assert_equal nil, array[4..4] # [] expected (or both nils in 
array[3..3] and array[4..4])
 end

Same behaviour can be reproduced on ruby 1.8.7 (2010-12-23 patchlevel 
330) [x86_64-linux].
=end