From: Nobuyoshi Nakada <nobu@...>
Date: 2007-07-12T10:54:57+09:00
Subject: Re: Returning part of a hash

Hi,

At Thu, 12 Jul 2007 05:30:03 +0900,
barjunk wrote in [ruby-talk:258922]:
> I have hash that has about 20 keys.  I'd like to create a new variable
> with just three of those keys.  Example:
> 
> hash = { "key1" => "value1",
>                "key2" => "value2",
>                ...
>                "key20" => "value20" }
> 
> And a function like:
> newhash = hash.slice("key2","key5","key7")

Hash#slice doesn't exist but Hash#select in recent 1.9 works
similarly.

  keys = %w"key2 key5 key7"
  newhash = hash.select {|k,v| keys.include?(k)}

It would be easy to define Hash#slice with this.

-- 
Nobu Nakada