From: Stefan Arentz <stefan.arentz@...>
Date: 2003-07-05T09:01:49+09:00
Subject: Re: Ruby Code Snippet: Array.count

Ian Macdonald <ian@caliban.org> writes:

> On Sat 05 Jul 2003 at 08:01:38 +0900, Stefan Arentz wrote:
> 
> > 
> > Maybe this functionality is already somewhere in Ruby, but I could not
> > find it. This little snippet extends Array with a count method. It takes
> > a code block that can be used to count elements that match a specific
> > condition:
> > 
> >  a = Array[1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
> >  puts a.count { |v| v < 5 }
> 
> This is already available with Enumerable#find_all:
> 
> a = (1..10).to_a
> puts a.find_all {|v| v < 5 }.size
> 
> 4

Yes but this is very inefficient if you have large collections. My version
does not need to create a new temporary collection just to count it.

 S.