ruby - How can I get all the responses by a particular user to posts on a particular topic -

i have user, micropost , response model.

the user has many microposts , has many responses.

microposts have tags using acts taggable gem.

i need find number of responses user has, microposts tagged specific tag. clear, example, how many responses has user 1 given microposts on "exercise"

there basic ruby syntax , relationship logic missing. haev in user model.

  def user_responses_on_topic tag       microposts = self.microposts.tagged_with(tag, :on => :tags)       responses_count = 0       microposts.each |micropost|           count = micropost.responses.where("user_id = :user_id", user_id: self.id).size           responses_count  = responses_count + count      end    end 

its giving me value know wrong because when add responses on particular topic users value doesn't increase.

i sure there simple "ruby" way @ using

   responses = user.microposts.responses  

but need know how tagged logic on microposts code

i have tightened bit still not luck. individual components of code work can't whole thing work together

 def user_responses_on_topic(interest)     microposts = micropost.tagged_with(interest, :on => :tags, :any => true)     responses ||= 0     microposts.each |micropost|     responses += micropost.responses.where("user_id = :user_id", user_id: self.id).size    end  end 

edit:

this works

def user_responses_on_topic(interest)    microposts = micropost.tagged_with(interest, :on => :tags, :any => true)    count = 0      microposts.each |micropost|      responses = micropost.responses.size      count = count + responses     end    count end 

but there's got better rails way (this smells of php)

any ideas?

if of components working independently, might simple adding line end of method: responses. after .each loop executes, returns original array (not value modified within loop). since want return number stored in responses, want variable last line of method.