Asp Forum - Search objects

Dark Ambient

8/13/2006 5:54:00 PM

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")

5 Answers

Morton Goldberg

8/13/2006 6:52:00 PM

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/)
# =>
# #<Composer:0x24a18 @country="Germany", @lname="Beethoven">
# #<Composer:0x24964 @country="Germany", @lname="Bach">
# #<Composer:0x24928 @country="Spain", @lname="Rodrigo">
# #<Composer:0x248ec @country="France", @lname="Ravel">

Regards, Morton

On Aug 13, 2006, at 1:54 PM, Dark Ambient wrote:

> 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")
>

Dark Ambient

8/13/2006 7:02:00 PM

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 8/13/06, Morton Goldberg <m_goldberg@ameritech.net> wrote:
> 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/)
> # =>
> # #<Composer:0x24a18 @country="Germany", @lname="Beethoven">
> # #<Composer:0x24964 @country="Germany", @lname="Bach">
> # #<Composer:0x24928 @country="Spain", @lname="Rodrigo">
> # #<Composer:0x248ec @country="France", @lname="Ravel">
>
> Regards, Morton
>
>
> On Aug 13, 2006, at 1:54 PM, Dark Ambient wrote:
>
> > 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")
> >
>
>
>

James Gray

8/13/2006 7:03:00 PM

On Aug 13, 2006, at 12:54 PM, Dark Ambient wrote:

> 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")

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 Gray II

Ara.T.Howard

8/13/2006 7:26:00 PM

Dark Ambient

8/13/2006 9:12:00 PM

That's a lot of food :)

Stuart

On 8/13/06, ara.t.howard@noaa.gov <ara.t.howard@noaa.gov> wrote:
> On Mon, 14 Aug 2006, Dark Ambient wrote:
>
> > 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")
> >
>
> 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
> --
> to foster inner awareness, introspection, and reasoning is more efficient than
> meditation and prayer.
> - h.h. the 14th dali lama
>
>

comp.lang.ruby

Search objects

Dark Ambient

Morton Goldberg

Dark Ambient

James Gray

Ara.T.Howard

Dark Ambient

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