From: gotoken@... (GOTO Kentaro)
Date: 2001-03-07T15:36:29+09:00
Subject: [ruby-talk:12210] Re: (long) Re: hash.invert loses data if equal values exist - is this the right behaviour?

Hi, 

In message "[ruby-talk:12179] Re: (long) Re: hash.invert loses data if equal values exist - is this the right behaviour?"
    on 01/03/07, Dave Thomas <Dave@PragmaticProgrammer.com> writes:
>To be fair, the example does show it:
>
>  dave[14:58:19] ri invert
>  ----------------------------------------------------------------------
>     hsh.invert -> aHash
>  ----------------------------------------------------------------------
>     Returns a new hash created by using hsh's values as keys, and the
>     keys as values.
>
>        h = { "n" => 100, "m" => 100, "y" => 300, "d" => 200, "a" => 0 }
>        h.invert   #=> {200=>"d", 300=>"y", 0=>"a", 100=>"n"}
>
>
>Should we make it more explicit?

I hope so.  Could you add some explicit notices like the below?

  ----------------------------------------------------------------------
     hsh.invert -> aHash
  ----------------------------------------------------------------------
     Returns a new hash created by using hsh's values as keys, and the
     keys as values.  Note that the result is uncertain if equvalent 
     hsh's values are associated to different keys. 

        h = { "n" => 100, "m" => 100, "y" => 300, "d" => 200, "a" => 0 }
        h.invert   #=> {200=>"d", 300=>"y", 0=>"a", 100=>"n"}

Thanks, 

-- Gotoken