problems accessing variables in a loop within my view - ruby-on-rails

Question

I'm fairly new to Ruby/Rails and I'm having a weird issue that I can't seem to understand what exactly I'm doing wrong.
I have the following code in my view
<% gameNum = 0 %>
gameNum: <%= gameNum %>
homeTeamIndex: <%= #games[gameNum].homeTeamIndex %>
awayTeamIndex: <%= #games[gameNum].awayTeamIndex %><br />
<%= #NflTeams[#games[gameNum].homeTeamIndex].name %>
<%= #NflTeams[#games[gameNum].awayTeamIndex].name %><br />
<% gameNum = 1 %>
gameNum: <%= gameNum %>
homeTeamIndex: <%= #games[gameNum].homeTeamIndex %>
awayTeamIndex: <%= #games[gameNum].awayTeamIndex %><br />
<%= #NflTeams[#games[gameNum].homeTeamIndex].name %>
<%= #NflTeams[#games[gameNum].awayTeamIndex].name %><br />
<% (0..#games.count).each do |gameNum| %>
gameNum: <%= gameNum %>
homeTeamIndex: <%#= #games[gameNum].homeTeamIndex %>
awayTeamIndex: <%#= #games[gameNum].awayTeamIndex %> <br />
<%#= #NflTeams[#games[gameNum].homeTeamIndex].name %>
<%#= #NflTeams[#games[gameNum].awayTeamIndex].name %>
<% end %>
And I get the following results when I view my view:
gameNum: 0 homeTeamIndex: 10 awayTeamIndex: 3
Detroit Lions Buffalo Bills
gameNum: 1 homeTeamIndex: awayTeamIndex:
Cinncinatti Bengals Cleveland Browns
gameNum: 0 homeTeamIndex: awayTeamIndex:
homeTeamIndex: awayTeamIndex:
gameNum: 1 homeTeamIndex: awayTeamIndex:
homeTeamIndex: awayTeamIndex:
gameNum: 2 homeTeamIndex: awayTeamIndex:
homeTeamIndex: awayTeamIndex:
gameNum: 3 homeTeamIndex: awayTeamIndex:
homeTeamIndex: awayTeamIndex:
gameNum: 4 homeTeamIndex: awayTeamIndex:
However, if I uncomment any of the lines:
homeTeamIndex: <%#= #games[gameNum].homeTeamIndex %>
awayTeamIndex: <%#= #games[gameNum].awayTeamIndex %> <br />
<%#= #NflTeams[#games[gameNum].homeTeamIndex].name %>
<%#= #NflTeams[#games[gameNum].awayTeamIndex].name %>
I get the following error(method name changes based on which line I uncomment):
undefined method `homeTeamIndex' for nil:NilClass
I really don't understand what is happening within the loop that makes the instance variables unavailable.
I'm hoping someone can tell me what the heck I'm doing wrong because this sure seems like a simple thing to do in a view and I can't get it to work.
UPDATE
I changed my view as follows, per Dmitry's advice:
<% gameNum = 0 %>
<% (#games).each do |game| %>
<strong>Game <%= gameNum+1 %> </strong> <br />
<%= image_tag(#NflTeams[game.homeTeamIndex].imagePath,
size: "40") %>
<%= #NflTeams[game.homeTeamIndex].name %>
VS
<%= image_tag(#NflTeams[game.awayTeamIndex].imagePath,
size: "40") %>
<%= #NflTeams[game.awayTeamIndex].name %> <br />
<% gameNum += 1 %>
<% end %>
And the Models are as follows:
NflTeams
class CreateNflTeams < ActiveRecord::Migration
def change
create_table :nfl_teams do |t|
t.string :name
t.string :imagePath
t.timestamps
end
end
end
Game
class CreateGames < ActiveRecord::Migration
def change
create_table :games do |t|
t.integer :homeTeamIndex
t.integer :awayTeamIndex
t.integer :spread
t.integer :week_id
t.timestamps
end
end
end
The awayTeamIndex and homTeamIndex are an index into the NflTeams model so I can easily pull out the Name and ImagePath.
I am still getting the undefined method on the line:
<%= image_tag(#NflTeams[game.homeTeamIndex].imagePath,
size: "40") %>
Any other suggestions?
UPDATE 2
I only included the migrations because there isn't much in the models for these two models.
But here it is.
class NflTeam < ActiveRecord::Base
end
class Game < ActiveRecord::Base
belongs_to :week
validates :homeTeamIndex, :inclusion => { :in => 0..100 }
validates :awayTeamIndex, :inclusion => { :in => 0..100 }
end
And here is the controller code:
class WeeksController < ApplicationController
before_action :signed_in_user
before_action :confirmed_user
...
def show
#week = Week.find(params[:id])
#games = #week.games
#NflTeams = NflTeam.all
end
...
end

Answer 1

You are not accessing you #games in a loop correctly. It looks like you are thinking about gameNum in this line:
<% (0..#games.count).each do |gameNum| %>
as if it is a numerical index and using it to access an object in a collection, in the following line:
homeTeamIndex: <%#= #games[gameNum].homeTeamIndex %>
This is wrong because "gameNum" is actually your object from a collection of #games fetched for you by magic ruby, so what you need is something like this:
<% (#games).each do |game| %>
gameNum: <%= game.number %>
homeTeamIndex: <%= game.homeTeamIndex %>
awayTeamIndex: <%= game.awayTeamIndex %> <br />
<%= game.homeTeam.name %>
<%= game.awayTeam.name %>
<% end %>
Hope this helps :)
P.S.
This solution depends on how your models are set up of course, if you can show those it might make your problem clearer for others to explain.
EDIT - Complete solution
I will just show you the way to present a peace of info as in your solution.
To start off a small advise, you mentioned in your comment
changed it to just query the database in the form for both the
homeTeamIndex and the awayTeamIndex
While this might work it is a bad practice to place such routines in the view, it is better to define a method to complete such routine in the helper and call it in the view.
Now, to the solution...
First you need to properly define model associations, which are only partially defined judging from the code you have shared. What you need is:
Tell all classes that they are related (which they are) like this:
I would loose 'Nfl' in team since it makes naming of classes confusing
class Week < ActiveRecord::Base
has_many :games
end
class Game < ActiveRecord::Base
belongs_to :week
belongs_to :home_team, class_name: "Team", foreign_key: :home_team_id
belongs_to :away_team, class_name: "Team", foreign_key: :away_team_id
end
class Team < ActiveRecord::Base
has_many :home_games, class_name: "Game", foreign_key: :home_team_id
has_many :away_games, class_name: "Game", foreign_key: :away_team_id
end
Note: Have a look at Active Record Associations for a more in-depth understanding of those.
EDIT
Corrected model associations above and tested to make sure those are working:)
Make sure you have the following database schema to back up the associations...
create_table "games", force: true do |t|
t.integer "game_number"
t.integer "week_id"
t.datetime "created_at"
t.datetime "updated_at"
t.integer "home_team_id"
t.integer "away_team_id"
end
create_table "teams", force: true do |t|
t.datetime "created_at"
t.datetime "updated_at"
end
create_table "weeks", force: true do |t|
t.string "name"
t.datetime "created_at"
t.datetime "updated_at"
end
EDIT: mind the fact that all tables do include id field by default when you create models in rails
With these associations in place you can now get the week in your controller as you did before:
class WeeksController < ApplicationController
...
def show
#week = Week.find(params[:id])
#games = #week.games
end
...
end
And finally construct your view:
In WeeksController#show
/views/weeks/show.html.erb
<% if #games.any? %>
<% render #games %>
<% end %>
This line "render #games' will search for '/views/games/_game.html.erb' and render it for every game in the collection #games
*/views/games/_game.html.erb - partial view*
<strong> Game <%= game.game_number %> </strong> <br />
<%= image_tag(game.home_team.imagePath, size: "40") %>
<%= game.home_team.name %>
VS
<%= image_tag(game.away_team.imagePath, size: "40") %>
<%= game.away_team.name %> <br />
And that is it, the only fiddly bit is getting the model associations wright which is not too difficult.