From: barjunk <barjunk@...>
Date: 2007-07-12T05:45:02+09:00
Subject: Re: Returning part of a hash

On Jul 11, 12:28 pm, barjunk <barj...@attglobal.net> wrote:
> 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")
>
> Which creates:
>
> newhash = { "key2" => "value1",
>                "key5" => "value5",
>                "key7" => "value7" }
>
> hash.select {|key, value| key == "key1" }
>
> I could do the above multiple times, but this returns an array not the
> hash pair.
>
> Thanks for any help.
>
> Mike B.


This is backwards, but works:
["key1","key2","key3","key2"].each {|item| hash.delete_if { |
key,value| key == item} }

This would get rid of the keys I don't want.

I could probably do something like:

(hash.keys - ["keys", "I", "want"]).each {|item| hash.delete_if { |
key,value| key == item} }


The only bummer is that directly modifies the hash...but that can be
fixed too.

I'm still new at this...is there a more succinct way?

Mike B.