From: Marcin Wolski <wolskint@...2.pl>
Date: 2010-06-04T10:41:29+09:00
Subject: Re: comparing objects

Anderson Leite wrote:
> How can I compare two objects and get true if some of his atributes are
> equals ?
> 
> I need to compare two arrays of users, and get and third array just with
> the matches. I found the "&" method that work for Fixnuns and String,
> but...how to use with objects ?
> 
> 
> class User
>  attr_accessor :email
> end
> 
> a = User.new
> a.email = 'ruby@rails.com'
> 
> b = User.new
> b.email = 'ruby@rails.com'
> 
> array_one = [a]
> array_two = [b]
> 
> 
> array_three = array_one & array_two
> 
> puts array_three # I want the user here
> 
> 
> 
> Can you help me ?
> thanks

I think you need to define how to compare your objects and their hash. 
Have a look below.


class User
 attr_accessor :email

 def ==(other)
  @email == other.email
 end

 alias eql? ==

 def hash
    code = 17
    code = 37*code + @email.hash
end

 def to_s
  "#@email"
 end

end

a = User.new
a.email = 'ruby@rails.com'

c = User.new
c.email = 'groovy@rails.com'

b = User.new
b.email = 'ruby@rails.com'

d = User.new
d.email = 'c++@rails.com'

d = User.new
d.email = 'python@rails.com'

array_one = [a,d]
array_two = [b, c]


array_three = array_one & array_two

puts array_three # I want the user here
#prints ruby@rails.com
-- 
Posted via http://www.ruby-forum.com/.