CODEWITHSUNDEEP
ruby-on-railsruby
Kirk
Kirk

Reputation: 108

How do I use an array of object parameters to set the value of

I have an array of parameters that are shared between two objects. 

attributes = [:name, :category, :value]

The first object already has those parameters set. I would like to pass those same values onto the second object.

How do I do this?

My initial thought was to use:

attributes.each do |attribute|
    @object_2.(attribute) = object_1.(attribute)
end

I also tried putting the attribute variable inside of "#{attribute}" but it still did not work.

I've tried a number of different solutions with no help, and Googling the answer for the past hour has not helped.

Some of the results seemed to suggest that I could accomplish what I was looking for with the send() method, but my attempts to use it did not help.

attributes.each do |attribute|
    @object_2.send(attribute) = object_1.send(attribute)
end

If this question has been answered before (I could not find a solution by extensive searching) please point me towards a solution.

Thanks.

Upvotes: 0

Views: 103

Answers (4)

Arup Rakshit
Arup Rakshit

Reputation: 118289

This is just a Hint about how this can also be done:

class Fred
  def initialize(p1 = nil, p2 = nil)
    @a, @b = p1, p2
  end
  def show
   p [@a,@b]
  end
end

f1 = Fred.new(10,11)
f2 = Fred.new
f1.instance_variables.each do |v|
  f2.instance_variable_set(v,f1.instance_variable_get(v))
end
f2.show #=>[10, 11

You can also replace f1.instance_variables by attributes, if you want assignments to only some selected instance variables,not all.

Upvotes: 2

Neil Slater
Neil Slater

Reputation: 27207

You are probably close in your last attempt, assuming you have declared attr_accessor for all the attributes in the respective class(es):

attributes.each do |attribute|
    setter = (attribute.to_s + '=').to_sym
    @object_2.send( setter, object_1.send( attribute ) )
end

The .to_sym is optional, I just like to work with symbols when working with introspection.

There are also ways to do this without needing the instance variables exposed via attr_accessor (it's not clear whether you need that)

Upvotes: 1

sawa
sawa

Reputation: 168199

attributes.each do |attribute|
    @object_2.send("#{attribute}=", object_1.send(attribute))
end

Upvotes: 3

ck3g
ck3g

Reputation: 5929

@object_2.attributes = object_1.attributes

Upvotes: 1

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