Re: Array#uniq vs Array#-

Hi, Gerald.

The RDoc also says that Array#- uses both #hash and #eql? methods. But
in my example I implemented just the #eql? method and worked:

[Any.new] - [Any.new]
=> []

In other words: why Array#- do not require that elements implement
#hash method for make equality comparison, as said in documentation?

Cheers.

On Tue, Apr 16, 2019 at 8:04 PM Gerald Bauer <[email protected]> wrote:
>
> Hello,
>
>    Just looked at the 1st result in the "ruby uniq" Google search,
> that is, the official Array RDoc [1].
>
>     If you look at Array#uniq it tells you:
>
> > It compares values using their hash and eql? methods for efficiency.
>
>    If you try it. Add to your Any class:
>
>    def hash() 1; end
>
>    And retry:
>
>   [Any.new,Any.new].uniq
>   => [#<Any:0x111>]
>
>     Now it works as you expect.  Cheers. Prost.
>
> [1] https://ruby-doc.org/core-2.5.0/Array.html#method-i-uniq
>
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