From: Robert Klemme <shortcutter@...>
Date: 2009-11-05T17:18:49+09:00
Subject: Re: Hash#count

2009/11/4 Paul Smith <paul@pollyandpaul.co.uk>:
> On Wed, Nov 4, 2009 at 4:19 PM, Intransition <transfire@gmail.com> wrote:
>> I want to suggest Hash#count be defined such that it counts hash
>> values. A it stands (using Enumerable#count) it only can ever return 0
>> or 1.

I opt against because that would make Hash's #count behave differently
than other Enumerable's #count plus there is a solution already as
show by Paul.

>> 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
>>
>
>
> {:a=>1,:b=2,:c=>1}.count{|x| x[1]==1}      #=> 2

Btw, there is a typo before 2.  This does not even compile on my Ruby versions:

09:18:06 tmp$ allruby -ce '{:a=>1,:b=2,:c=>1}.count{|x| x[1]==1}'
CYGWIN_NT-5.1 padrklemme1 1.5.25(0.156/4/2) 2008-06-12 19:34 i686 Cygwin
========================================
ruby 1.8.7 (2008-08-11 patchlevel 72) [i386-cygwin]
-e:1: syntax error, unexpected tINTEGER, expecting tASSOC
{:a=>1,:b=2,:c=>1}.count{|x| x[1]==1}
           ^
-e:1: warning: useless use of a literal in void context
========================================
ruby 1.9.1p129 (2009-05-12 revision 23412) [i386-cygwin]
-e:1: syntax error, unexpected tINTEGER, expecting tASSOC
{:a=>1,:b=2,:c=>1}.count{|x| x[1]==1}
           ^
09:18:17 tmp$

You can also do

irb(main):019:0> {:a=>1,:b=>2,:c=>1}.count {|k,v| v == 1}
=> 2

Kind regards

robert

-- 
remember.guy do |as, often| as.you_can - without end
http://blog.rubybestpractices.com/