[#407882] Ruby extremely slow compared to PHP — Mick Jagger <lists@...>

Hello there, how are you? Hope you are fine. I am a PHP programmer

17 messages 2013/06/02

[#407908] TCPServer/Socket and Marshal problem — Panagiotis Atmatzidis <atma@...>

Hello,

18 messages 2013/06/03

[#407946] Is rubyquiz.com dead? — Alphonse 23 <lists@...>

Thread title says everything.

18 messages 2013/06/04

[#408012] Need help understanding recursion. — pedro oliva <lists@...>

Ive been reading Chris Pine's book 'Learn to Program' and its been going

11 messages 2013/06/06

[#408129] Getting Started With Development — Chamila Wijayarathna <cdwijayarathna@...>

I'm new to Ruby Development. I downloaded source from Github, but couldn't

24 messages 2013/06/11
[#408131] Re: Getting Started With Development — Per-erik Martin <lists@...> 2013/06/11

Ruby is often installed on linux, or can be easily installed with the

[#408146] Re: Getting Started With Development — "Chamila W." <lists@...> 2013/06/11

Per-erik Martin wrote in post #1112021:

[#408149] Re: Getting Started With Development — "Carlo E. Prelz" <fluido@...> 2013/06/11

Subject: Re: Getting Started With Development

[#408198] NokoGiri XML Parser — "Devender P." <lists@...>

Hi,

11 messages 2013/06/13

[#408201] trying to load a .rb file in irb — "Eric D." <lists@...>

I am trying to load a ruby program into irb and it will not load.

12 messages 2013/06/13

[#408205] Can I use Sinatra to render dynamic pages? — Ruby Student <ruby.student@...>

Hell Team,

18 messages 2013/06/13
[#408219] Re: Can I use Sinatra to render dynamic pages? — Nicholas Van Weerdenburg <vanweerd@...> 2013/06/14

You should be able to do this without JavaScript by using streaming.

[#408228] Re: Can I use Sinatra to render dynamic pages? — Ruby Student <ruby.student@...> 2013/06/14

Well, I got some good suggestions from everyone here. I thank you all for

[#408275] Compare and sort one array according to another. — masta Blasta <lists@...>

I have two arrays of objects that look something like this:

14 messages 2013/06/17

[#408276] Comparing objects — "Thom T." <lists@...>

How do I compare two objects in Ruby, considering only attributes

15 messages 2013/06/17

[#408307] getting the most out of Ruby — robin wood <lists@...>

I write a lot of scripts in Ruby, most are small simple things but some

13 messages 2013/06/18

[#408309] Creating ruby script exe — Rochit Sen <lists@...>

Hi All,

17 messages 2013/06/18

[#408357] Beginners problem with database and datamapper — cristian cristian <lists@...>

Hi all!

28 messages 2013/06/20

[#408437] How do I input a variable floating point number into Ruby Programs — "Michael P F." <lists@...>

I want to evaluate the following interactively:

10 messages 2013/06/23

[#408518] #!/usr/bin/env: No such file or directory — Todd Sterben <lists@...>

I am new to both linux and ruby. I am using Ubuntu and Ruby 1.9

17 messages 2013/06/27

[#408528] Designing a Cabinet class — Mike Vezzani <lists@...>

Hello all,

12 messages 2013/06/27

[#408561] Find elment in array of hashes — Rodrigo Lueneberg <lists@...>

array = {:id=>1, :price =>0.25} # index[0]

23 messages 2013/06/28

Re: Compare and sort one array according to another.

From: masta Blasta <lists@...>
Date: 2013-06-18 17:46:36 UTC
List: ruby-talk #408319
Robert Klemme wrote in post #1112735:
> On Mon, Jun 17, 2013 at 11:35 PM, Douglas Seifert <doug@dseifert.net>
> wrote:
>
>> You have said that the size of your two arrays is small, so the fact that
>> the find_index based solution is o(n^2) probably doesn't matter.
>>
>
> Yes, that's what I was figuring.  Your analysis is spot on.
>
>
>>  For kicks, a o(n) solution compared to the o(n^2) solution here:
>>
>> https://gist.github.com/seifertd/5800639
>>
>> It involves precomputing a lookup index for the data you need to sort.
>>
>
> Your "gen_lookup:" is exactly what I'd did for larger arrays.
>
> Kind regards
>
> robert

This has been a great little learning exercise for me. I had never quite 
gotten how the sort_by method worked, and now reading it over again with 
the example it's perfectly clear.

I'm surprised at how slow the method is. In the benchmark, 1.24s for 10 
records...?? That's huge! The SQL query to fetch the records already 
sorted, as big and messy as it is, still only takes 10ms. I might have 
to stick with SQL on this one since for a Rails app response time is 
critical.

I'm certainly glad I came and asked for help about this.

-- 
Posted via http://www.ruby-forum.com/.

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