From: Robert Klemme <shortcutter@...>
Date: 2008-03-25T19:23:50+09:00
Subject: Re: numbers of a record in an array

2008/3/25, Jesús Gabriel y Galán <jgabrielygalan@gmail.com>:
> On Tue, Mar 25, 2008 at 10:09 AM, Bu Mihai <mihai.bulhac@yahoo.com> wrote:
>  > a have an array array=["a","b","c","a","b"]
>  >  how can i find the numbers of "a", "b","c" items in the array?
>
>
> Here's one way:
>
>  irb(main):006:0> a = %w{a b a c b a c c}
>  => ["a", "b", "a", "c", "b", "a", "c", "c"]
>  irb(main):007:0> h = Hash.new {|h,k| h[k] = 0}
>  => {}
>  irb(main):008:0> a.each {|x| h[x] += 1}
>  => ["a", "b", "a", "c", "b", "a", "c", "c"]
>  irb(main):009:0> h
>  => {"a"=>3, "b"=>2, "c"=>3}

Here's another

irb(main):001:0> a = %w{a b a c b a c c}
=> ["a", "b", "a", "c", "b", "a", "c", "c"]
irb(main):002:0> a.inject(Hash.new(0)){|cnt,e| cnt[e]+=1; cnt}
=> {"a"=>3, "b"=>2, "c"=>3}

Jesús, note that you do not need the block form of Hash.new because of
the way + works.  It is sufficient to make 0 the default element.

Kind regards

robert

-- 
use.inject do |as, often| as.you_can - without end