[LRUG] Sorting a hash by value

[George Drummond]

My solution

#######

require 'ostruct'

collection = {
  "ami-c3c73c7f"=>"tn-example 1980-09-12T17:53:25Z",
  "ami-600925fe"=>"sns-example 1983-01-05T16:21:08Z",
  "ami-131f1007"=>"dk-example 2005-01-27T23:03:01Z",
  "ami-98d4ddef"=>"tn-example 2002-10-27T11:52:26Z",
  "ami-fe6af742"=>"sns-example 1998-11-22T09:54:51Z",
  "ami-09966e45"=>"dk-example 1993-01-09T13:23:45Z",
  "ami-44e6ee6a"=>"tn-example 2013-12-23T20:52:28Z",
  "ami-cbf7f1a9"=>"sns-example 1979-09-09T07:15:47Z",
  "ami-fcd2e7ac"=>"dk-example 2007-09-02T18:34:05Z"
}

collection_hash = collection.map do |id, value|
  type, timestamp = value.split(' ')

  OpenStruct.new(
    id: id,
    type: type,
    timestamp: Time.new(timestamp)
  )
end

collection_hash.select { |item| item.type == 'sns-example'
}.sort_by(&:timestamp)

#######



On Tue, Jun 17, 2014 at 10:16 PM, Gerhard Lazu <gerhard at lazu.co.uk> wrote:

> I really like Tom's approach, I'm somewhat expanding on it:
> https://gist.github.com/gerhard/7203f3bb51d1ad59c886
>
>
> ------------------------------
> Twitter <http://twitter.com/#!/gerhardlazu> Github
> <https://github.com/gerhard> Blog <http://gerhard.lazu.co.uk/>
>
>
> On Tue, Jun 17, 2014 at 11:46 AM, Stephen Nelson-Smith <sanelson at gmail.com
> > wrote:
>
>> I have a hash that looks like this:
>>
>> {"ami-c3c73c7f"=>"tn-example 1980-09-12T17:53:25Z",
>>  "ami-600925fe"=>"sns-example 1983-01-05T16:21:08Z",
>>  "ami-131f1007"=>"dk-example 2005-01-27T23:03:01Z",
>>  "ami-98d4ddef"=>"tn-example 2002-10-27T11:52:26Z",
>>  "ami-fe6af742"=>"sns-example 1998-11-22T09:54:51Z",
>>  "ami-09966e45"=>"dk-example 1993-01-09T13:23:45Z",
>>  "ami-44e6ee6a"=>"tn-example 2013-12-23T20:52:28Z",
>>  "ami-cbf7f1a9"=>"sns-example 1979-09-09T07:15:47Z",
>>  "ami-fcd2e7ac"=>"dk-example 2007-09-02T18:34:05Z"}
>>
>> I want to filter this hash by value and return them in sorted date order.
>>  The implementation I have just seems ugly:
>>
>> catalogue.select {|id, name| name.match /sns-example/ }.sort { |id, name|
>> name[1] <=> id[1] }
>> => [["ami-a65e21cc", "sns-example 2011-10-03T11:15:49Z"],
>>  ["ami-9a401c41", "sns-example 1983-09-22T15:26:00Z"],
>>  ["ami-9f9ae4d8", "sns-example 1971-03-06T03:58:52Z"]]
>>
>>
>> I don't like the way sort takes my hash and makes it into an array of
>> tuples... and I'd really like it to return an array of single key/value
>> hashes...
>>
>> Also, is there a more elegant way to perform the filter/search?
>>
>> S.
>>
>> --
>> Stephen Nelson-Smith
>> Technical Director
>> Atalanta Systems Ltd
>> www.atalanta-systems.com
>>
>> _______________________________________________
>> Chat mailing list
>> Chat at lists.lrug.org
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>>
>>
>
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