From: Patrick Hurley <phurley@...>
Date: 2006-08-27T12:46:30+09:00
Subject: Re: Ruby == how does it works?

On 8/26/06, Surendra Singhi <efuzzyone@netscape.net> wrote:
> >>   Does the Ruby '==' operator compares the 'object_ids' of the
> >> element before
> >> descending into comparing the elements?
> >
> > Depends on how the object receiving it implements it.
> >
> And how does hashes, and arrays implement it?


ri Hash#==
---------------------------------------------------------------- Hash#==
     hsh == other_hash    => true or false
------------------------------------------------------------------------
     Equality---Two hashes are equal if they each contain the same
     number of keys and if each key-value pair is equal to (according to
     +Object#==+) the corresponding elements in the other hash.

        h1 = { "a" => 1, "c" => 2 }
        h2 = { 7 => 35, "c" => 2, "a" => 1 }
        h3 = { "a" => 1, "c" => 2, 7 => 35 }
        h4 = { "a" => 1, "d" => 2, "f" => 35 }
        h1 == h2   #=> false
        h2 == h3   #=> true
        h3 == h4   #=> false

ri Arrray#==
--------------------------------------------------------------- Array#==
     array == other_array   ->   bool
------------------------------------------------------------------------
     Equality---Two arrays are equal if they contain the same number of
     elements and if each element is equal to (according to Object.==)
     the corresponding element in the other array.

        [ "a", "c" ]    == [ "a", "c", 7 ]     #=> false
        [ "a", "c", 7 ] == [ "a", "c", 7 ]     #=> true
        [ "a", "c", 7 ] == [ "a", "d", "f" ]   #=> false