From: Serg Koren <skoren@...>
Date: 2008-02-12T08:31:05+09:00
Subject: Re: Partial index hash search?

oops i took the easy way and replied. sorry.
Thanks for the help/explanation.   I was hoping there was a shorter/ 
more efficient  way than iterating maybe a nested hash of some sort.

Guess I'll settle for what we have.
Thanks much.

On Feb 11, 2008, at 5:24 PM, Eric I. wrote:

> On Feb 11, 3:47 pm, Serg Koren <sko...@comcast.net> wrote:
>> What's the best way to find all occurances of a string in a hash's
>> index?
>>
>> That is,
>>
>> x = { 'Hello' => 1, 'Goodbye' => 2, 'Hello there' => 3}
>>
>> How do I most efficiently get  1 and 3 to return on a search for
>> 'Hello' in the index of the hash?  I know I can iterate over the
>> index, but is there a better way?
>>
>> Thanks.
>
> Hi Serg,
>
> Here's one way to do it:
>
>
> x = { 'Hello' => 1, 'Goodbye' => 2, 'Hello there' => 3}
>
> result = x.keys.select { |k| k.include? "Hello" }.map { |k| x[k] }
> p result
>
>
> There's really no way to avoid iterating over the keys in the hash.
> In this case, Enumerable#select is doing that when it produces an
> array of the keys that contain "Hello".  That array of keys is
> converted into an array of values by using Enumerable#map.
>
> Eric
>
> P.S. It looks like you replied to a posting for Ruby Quiz #156.  Since
> this is unrelated to the Ruby Quiz, it would have been preferable to
> make a new post.
>
> ====
>
> Are you interested in on-site Ruby training that uses well-designed,
> real-world, hands-on exercises? http://LearnRuby.com
>