From: Intransition <transfire@...>
Date: 2009-11-11T00:49:04+09:00
Subject: Re: Hash#count



On Nov 9, 5:13 am, Yukihiro Matsumoto <m...@ruby-lang.org> wrote:
> Hi,
>
> In message "Re: Hash#count"
>     on Thu, 5 Nov 2009 01:19:13 +0900, Intransition <transf...@gmail.com> writes:
>
> |Current:
> |
> |  {:a=>1,:b=2,:c=>1}.count([:a,1]) #=> 1
> |  {:x=>1,:b=2,:c=>1}.count([:a,1]) #=> 0
> |  {:a=>1,:b=2,:c=>1}.count(1)      #=> 0
> |
> |Proposed:
> |
> |  {:a=>1,:b=2,:c=>1}.count(1) #=> 2
> |  {:x=>1,:b=2,:c=>1}.count(1) #=> 2
> |
> |It would be more useful that way.
>
> That is based on viewpoint to see hashes are collections of values
> indexed by arbitrary object.  But in reality, Ruby hashes are designed
> as collections of key-value pair.  I am not particularly against the
> object-indexed view, but I am not going to change the existing method
> behavior.

Okay. I only point out, if Hash is a collection key-value pairs, I
would expect Hash#include? to check pairs too.

Personally I like to see methods behave according to most common uses,
not an abstract viewpoint. I realize that is not always easy to
determine (YMMV and all that), but I think it's a worthy pursuit
nonetheless.

> |And, in the same vain, a #has_pair?
> |seems like an obvious addition.
>
> Let's address the issue one by one.

Sure.