Rails, model method returning array instead of iterating over the results

Question

new ruby on rails user here. I have a question about the following few lines of code.

First example in view.

<% sailing.travelling_parties.each do |party| %>
  <% party.party_registers.each do |reg| %>
    <%= reg.user.detailed_user.first_name %>
  <% end %>
<% end %>

When I run it in the in view, i get my expected result which is multiple names printed out. When I move it to the model and change it to the following,

Second example, in model. The ** represents what I'm actually trying to accomplish in this entire example.

class Sailing < ActiveRecord::Base

...

def gather_data
 self.travelling_parties.each do |party|
  party.party_registers.each do |reg|
    reg.user.detailed_user.first_name
    ** use a variable to count loop iterations **
  end
 end
end

Second example, in View

<%= sailing.gather_data %>

This is printing out an array filled with the 'travelling_parties' I am trying to iterate over, not what I had expected at all! So, obviously it only loops once regardless of how many names are in the sailing record.

Can any shed any light on why this is happening, and how I can get it to work like the first example, without actually putting my business logic in the view?

Thanks

Ilya · Accepted Answer · 2016-05-22 06:41:15Z

1

You can use Array#map, which transforms array into other array according to given block:

def gather_data
  travelling_parties.map do |party|
    party.party_registers.map do |reg|
      reg.user.detailed_user.first_name
    end
  end
end

This method returns array of arrays with first names. If you want get one-dimensional array, use flat_map instead of first map, like below:

def gather_data
  travelling_parties.flat_map do |party|
    party.party_registers.map do |reg|
      reg.user.detailed_user.first_name
    end
  end
end

edited May 22, 2016 at 6:41

answered May 22, 2016 at 6:34

Ilya

13.5k5 gold badges41 silver badges56 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Aptorian Over a year ago

Great! This is what I was looking for, thanks. Do you know know I would be able to get my array of names, AND get the count of names without having to call <p><%= sailing.gather_data.count %></p> AND <p><%= sailing.gather_data %></p> (basically doubling my query. Thanks again!

Ilya Over a year ago

@Aptorian, put sailing.gather_data into variable and use size instead of count on this variable

Collectives™ on Stack Overflow

Rails, model method returning array instead of iterating over the results

1 Answer 1

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related