# Search objects **URL:** \ **Category:** Ruby\ **Created:** [August 15, 2006, 2:19pm UTC](https://www.ruby-forum.com/t/search-objects/64800 "2006-08-15T14:19:08Z")\ **Posts on this page:** 6\ **Page:** 1

**Author:** ![zanoni](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/z/e99b99/32.png) [@zanoni](https://www.ruby-forum.com/u/zanoni)\ **Post date:** [August 15, 2006, 2:19pm UTC](https://www.ruby-forum.com/t/search-objects/64800/1 "2006-08-15T14:19:08Z")

I can use some help here: I’ve set up this class and objects and would like to “search” it similar to the way I would search a database. At this point I’m not concerned with adding regex for more liberal searches. Any suggestions ? class Composer def initialize( lname, country ) @lname = lname @country = country end attr\_accessor(:lname, :country) end comp1 = Composer.new(“Beethoven”, “Germany”) comp2 = Composer.new(“DeFalla”, “Spain”) comp3 = Composer.new(“Debussy”, “France”) ---

I’m assuming that you are just implementing this for its educational value and not seriously considering implementing a data base with this approach. Ruby has built-in and third-party libraries to help you implement a data bases application. I’ve modified your posting just enough to make a shallow scratch on the surface of what can be done to organize and search data. I hope it’s enough to help you along. Although you said you didn’t want to consider regular expressions yet, I use them because it makes life much simpler to use at least simple regexes. #! /usr/bin/ruby -w class Composer ``` @@composers = [] def Composer.find(attrib, regex) @@composers.select do |c| c.respond_to?(attrib) && c.send(attrib) =~ regex end end def initialize( lname, country ) @lname = lname @country = country @@composers << self end attr_accessor :lname, :country alias :to_s :inspect ``` end Composer.new(“Beethoven”, “Germany”) Composer.new(“DeFalla”, “Spain”) Composer.new(“Debussy”, “France”) Composer.new(“Bach”, “Germany”) Composer.new(“Rodrigo”, “Spain”) Composer.new(“Ravel”, “France”) puts Composer.find(:country, /^Ger/) puts Composer.find(:lname, /^R/) # =\> # #\ # #\ # #\ # #\ Regards, Morton ---

Well a few things. For some reason, in the past I’ve attempted to use ‘find’ in Ruby and irb has sent back a nomethod error. So perhaps t was syntax errors (though I don’t believe it was) not sure. I’m about to run out so I’ll check it in a while. And yes, this is for educational purposes though I think I may have not seen some options. Particularly the ability in Rails to play with models and controllers in the console. I know this is not the Rails list and I’ve gone ahead posted my errors while attempting to load the console using the NAME or DESCRIPTION option. Stuart ---

On Aug 13, 2006, at 12:54 PM, Dark A. wrote: > def initialize( lname, country ) > @lname = lname > @country = country > end > attr\_accessor(:lname, :country) > end > > comp1 = Composer.new(“Beethoven”, “Germany”) > comp2 = Composer.new(“DeFalla”, “Spain”) > comp3 = Composer.new(“Debussy”, “France”) Well, if we had those composers in an Array, we could use normal iterators like: composers.find { |c| c.country == “Germany” } and: composers.select { |c| c.lname =~ /^De/ } Hope that gives you some fresh ideas. James Edward G. II ---

On Mon, 14 Aug 2006, Dark A. wrote: > ``` > @country = country > > ``` > > end > attr\_accessor(:lname, :country) > end > > comp1 = Composer.new(“Beethoven”, “Germany”) > comp2 = Composer.new(“DeFalla”, “Spain”) > comp3 = Composer.new(“Debussy”, “France”) harp:~ \> cat a.rb require ‘weakref’ class Composer (ATTRIBUTES = %w( lname country )).each{|a| attr\_accessor a} INDEX = Hash.new{|h,k| h[k] = []} def self.find arg pattern = case arg when Hash ATTRIBUTES.map{|a| arg[a] || arg[a.to\_s] || arg[a.to\_s.intern]} when Array arg else raise ArgumentError end ``` n = pattern.size keys = INDEX.keys.select do |key| match = [] n.times do |i| pat, k = pattern[i], key[i] match << if pat.nil? true elsif pat.respond_to? 'call' pat.call(k) ? true : false elsif pat.respond_to? '===' pat === k elsif pat.respond_to? '==' pat == k else false end end match.all? end INDEX.values_at(*keys).map{|list| list.map{|weakref| ``` weakref. **getobj** }}.flatten end def initialize \*argv ATTRIBUTES.each{|a| send “#{ a }=”, argv.shift} key = ATTRIBUTES.map{|a| send a} val = WeakRef.new self INDEX[key] \<\< val end def to\_hash ATTRIBUTES.inject({}){|h,k| h.update k =\> send(k)} end def inspect to\_hash.inspect end def to\_s inspect end end comp1 = Composer.new “Beethoven”, “Germany” comp2 = Composer.new “DeFalla”, “Spain” comp3 = Composer.new “Debussy”, “France” found = Composer.find ‘lname’ =\> ‘Beethoven’ p found found = Composer.find ‘lname’ =\> %r/^bee|^defal/io p found found = Composer.find :country =\> lambda{|c| c.upcase === ‘SPAIN’} p found class CaseOf \< ::Array def ===(other) flatten.compact.map{|pat| pat === other}.any? end end def caseof(\*a, &b) CaseOf.new(\*a, &b) end found = Composer.find :lname =\> %r/y$/, :country =\> caseof(%w[ Spain France ]) p found harp:~ \> ruby a.rb [{“country”=\>“Germany”, “lname”=\>“Beethoven”}] [{“country”=\>“Germany”, “lname”=\>“Beethoven”}, {“country”=\>“Spain”, “lname”=\>“DeFalla”}] [{“country”=\>“Spain”, “lname”=\>“DeFalla”}] [{“country”=\>“France”, “lname”=\>“Debussy”}] food for thought. -a ---

That’s a lot of food 🙂 Stuart