Why is my name method undefined?

Question

I am receiving a undefined method `name' for # error for my Rails project. I know that name is defined for events by double checking using my console, so I don't understand why it won't load. Here is some of my code:

Apps Show:

<h1><%= @app.title %></h1>
<h5>App URL: <%= @app.url %></h5>
<h5>App User_id: <%= @app.user_id %></h5>
<br>

    <h2> Events </h2>
      <% @events.each do |event| %>
        <div>
          <%= event.name %><span class="badge"><%= event.count %></span>
        </div>
      <% end %>
    <br>
    <%= link_to "Edit", edit_app_path(@app), class: 'btn btn-success' %>

Apps Controller:

class AppsController < ApplicationController
  def create
    @app = App.new(params.require(:app).permit(:title, :url))
    @app.user_id = 1
    if @app.save
      flash[:notice] = "App was saved!"
      redirect_to @app
    else
      flash[:error] = "There an error, oh noes!Please try again!"
      render :new
    end
  end

  def new
    @app = App.new
  end

  def show
    @app = App.find(params[:id])
    @events = @app.events.group_by(&:name)
  end

  def index
    @apps = App.all
  end

  def edit
    @app = App.find(params[:id])
  end

  def update
    @app = App.find(params[:id])
     if @app.update_attributes(params.require(:app).permit(:title, :url))
       flash[:notice] = "Application was updated."
       redirect_to @app
     else
       flash[:error] = "There was an error saving the app. Please try again."
       render :edit
     end
  end

  def destroy
    @app = App.find(params[:id])
    if @app.destroy
      flash[:notice] = "App was removed."
      redirect_to @app
    else
      flash[:error] = "App couldn't be deleted. Try again."
      redirect_to @app
    end

     respond_to do |format|
       format.html
       format.js
     end
  end
end

Events Seed:

create_table "events", force: :cascade do |t|
    t.integer  "app_id"
    t.string   "name"
    t.datetime "created_at", null: false
    t.datetime "updated_at", null: false
  end

App Model:

class App < ActiveRecord::Base
  belongs_to :user
  has_many :events
end

Complete Error Log:

Completed 500 Internal Server Error in 19ms

ActionView::Template::Error (undefined method `name' for #<Array:0x007fcc53394af0>):
     6: <h2> Events </h2>
     7:   <% @events.each do |event| %>
     8:     <div>
     9:       <%= event.name %><span class="badge"><%= event.count %></span>
    10:     </div>
    11:   <% end %>
    12: <br>
  app/views/apps/show.html.erb:9:in `block in _app_views_apps_show_html_erb__2949113196422864311_70257764571040'
  app/views/apps/show.html.erb:7:in `each'
  app/views/apps/show.html.erb:7:in `_app_views_apps_show_html_erb__2949113196422864311_70257764571040'


  Rendered /Users/ericpark/.rvm/gems/ruby-2.2.0/gems/actionpack-4.2.0/lib/action_dispatch/middleware/templates/rescues/_source.erb (7.1ms)
  Rendered /Users/ericpark/.rvm/gems/ruby-2.2.0/gems/actionpack-4.2.0/lib/action_dispatch/middleware/templates/rescues/_trace.html.erb (4.1ms)
  Rendered /Users/ericpark/.rvm/gems/ruby-2.2.0/gems/actionpack-4.2.0/lib/action_dispatch/middleware/templates/rescues/_request_and_response.html.erb (0.9ms)
  Rendered /Users/ericpark/.rvm/gems/ruby-2.2.0/gems/actionpack-4.2.0/lib/action_dispatch/middleware/templates/rescues/template_error.html.erb within rescues/layout (71.2ms)
  Rendered /Users/ericpark/.rvm/gems/ruby-2.2.0/gems/web-console-2.1.3/lib/web_console/templates/_markup.html.erb (0.7ms)
  Rendered /Users/ericpark/.rvm/gems/ruby-2.2.0/gems/web-console-2.1.3/lib/web_console/templates/style.css.erb within layouts/inlined_string (0.7ms)
  Rendered /Users/ericpark/.rvm/gems/ruby-2.2.0/gems/web-console-2.1.3/lib/web_console/templates/_inner_console_markup.html.erb within layouts/inlined_string (0.5ms)
  Rendered /Users/ericpark/.rvm/gems/ruby-2.2.0/gems/web-console-2.1.3/lib/web_console/templates/_prompt_box_markup.html.erb within layouts/inlined_string (0.3ms)
  Rendered /Users/ericpark/.rvm/gems/ruby-2.2.0/gems/web-console-2.1.3/lib/web_console/templates/console.js.erb within layouts/javascript (69.6ms)
  Rendered /Users/ericpark/.rvm/gems/ruby-2.2.0/gems/web-console-2.1.3/lib/web_console/templates/main.js.erb within layouts/javascript (0.4ms)
  Rendered /Users/ericpark/.rvm/gems/ruby-2.2.0/gems/web-console-2.1.3/lib/web_console/templates/error_page.js.erb within layouts/javascript (0.7ms)
  Rendered /Users/ericpark/.rvm/gems/ruby-2.2.0/gems/web-console-2.1.3/lib/web_console/templates/index.html.erb (156.5ms)

Answer 1

In cases like this, simple debug printing will reveal the problem. Is name not defined on @events when you think it should be? Are you sure that @events is what you think it is?

Add p @events line to your controller, retry the request and read the log. A piece of advice for the future. :)

The problem starts here:

@events = @app.events.group_by(&:name)

I'm pretty sure that output of group_by is a hash, where keys are different names and values are arrays of events which all have the same name. (depends on what exactly the implementation of group_by is, of course)

<% @events.each do |event| %>

event here is not an instance of Event class, but a two element array, [name, [event1, event2, ...]]. You should iterate this nested array to get real events, which do have the method you want.

<% @events.each do |name, events| %>
  <%= name %> <%= events.length %>

Answer 2

@events is hash you have to iterate like

   <% @events.each do |event| %>
    <div>
      <%= event[0] %><span class="badge"><%= event[1].count %></span>
    </div>
  <% end %>