undefined method `each' for nil:NilClass within Pages#friends - ruby-on-rails

Question

I am trying to get my followers to display on the pages/friends however, I keep getting multiple errors like an undefined method `each' for nil:NilClass in my Pages#friends error. I am following Michael Harlts tutorials on follow/unfollow however, I needed to tweak a couple of things because I did not follow the entire thing.
When a user goes to their Friends link (pages/friends) I want it to display everyone who is following them. Like how my users/index displays everyone. Please see my code below. Any help of suggestions would be great.
Pages/friends
<h1>Friends</h1>
<% #user ||= current_user %>
<% #users.each do |user| %>
<center><%= link_to image_tag(user.avatar.url(:thumb)), user %></center>
<strong><center><br><%= link_to user.name, user %></br></center></strong>
<% if current_user.admin %>
<% end %>
<% end %>
Pages/controller
def home
end
def about
end
def friends
end
end
**Users/index*
<% provide(:title, 'All users') %>
<h1>All users</h1>
<div class="col-md-offset-4 col-med-8">
<div class="panel panel-default">
<div class="panel-heading center">
<% #users.each do |user| %>
<center><%= link_to image_tag(user.avatar.url(:thumb)), user %></center>
<strong><center><br><%= link_to user.name, user %></br></center></strong>
<% if current_user.admin %>
<% #user ||= current_user %>
<div class="stats">
<a href="<%= friends_path(#user) %>">
<strong id="following" class="stat">
<%= #user.followed_users.count %>
</strong>
following
</a>
<a href="<%= friends_path(#user) %>">
<strong id="followers" class="stat">
<%= #user.followers.count %>
</strong>
followers
</a>
</div>
<center><%= link_to "Delete", user, method: :delete, data: { confirm: "Are you sure?" } %></center>
<% end %>
<% end %>
<div class="center">
<%= will_paginate #users, renderer: BootstrapPagination::Rails %>
</div>
</div>
Routes
devise_for :admins
devise_for :users
resources :posts
resources :users do
member do
get :following, :followers
end
end
resources :relationships, only: [:create, :destroy]
resources :user_friendships do
member do
put :accept
end
end
get "users/show"
root "pages#home"
get 'feed', to: 'posts#index', as: :feed
get "about" => "pages#about"
get "friends" => 'pages#friends'
match 'users/:id' => 'users#show', via: :get
match 'users/:id' => 'users#index', via: :destroy
match 'users/:id' => 'users#destroy', via: :get
match 'users/:id' => 'users#destroy', via: :delete
get '/:id', to: 'users#show'
Users/controller
class UsersController < ApplicationController
before_action :correct_user, only: [:edit, :update, :destroy, :following, :followers]
before_action :authenticate_user!, except: [:index, :show]
before_action :admin_user, only: :destroy
def index
#users = User.paginate(page: params[:page], :per_page => 5)
end
def show
#user = User.find(params[:id])
if #user
#posts = #user.posts.all
render actions: :show
else
render file: 'public/404', status: 404, formats: [:html]
end
def destroy
User.find(params[:id]).destroy
flash[:success] = "Your account has been deleted."
redirect_to root_path
end
def correct_user
#user = User.find(params[:id])
redirect_to root_path
end
def admin_user
redirect_to root_path unless current_user.admin?
end
def following
#title = "Following"
#user = User.find(params[:id])
#users = #user.followed_users.paginate(page: params[:page])
render 'show_follow'
end
def followers
#title = "Followers"
#user = User.find(params[:id])
#users = #user.followers.paginate(page: params[:page])
render 'show_follow'
end
end
end
Relationships Controller
class RelationshipsController < ApplicationController
before_action :authenticate_user!, except: [:index, :show]
def create
#user = User.find(params[:relationship][:followed_id])
current_user.follow!(#user)
respond_to do |format|
format.html { redirect_to #user }
format.js
end
end
def destroy
#user = Relationship.find(params[:id]).followed
current_user.unfollow!(#user)
respond_to do |format|
format.html { redirect_to #user }
format.js
end
end
end

Answer 1

The error undefined method 'each' for nil:NilClass means that you're calling .each on an object that is nil.
For example, here, #users could be nil:
def index
#users = User.paginate(page: params[:page], :per_page => 5)
end
If you then call <% #users.each ... %>, you'll get the undefined method error. You've posted quite a lot of code above, so it's difficult to know exactly where that error is being thrown. Try and work out exactly where the error is being thrown (posting a stack trace would help), and work out which object is nil. Then work out why it's nil - is there no data? Or is your ActiveRecord query returning no results?
Hopefully that gives you some pointers as to where to start looking next.
Edit: As mmichael points out, the error is being caused due to the fact that #users was undeclared in pages#friends. Thanks!

Answer 2

As you're new, I'll give you another opinion. What I'm going to write is similar to Sam's answer; I intend to help you appreciate how Rails works, to further your experience
Objects
You must remember that Rails is built on top of Ruby - an object-orientated language. This means every time you declare / use a variable inside Ruby, you're actually accessing an object, which Ruby treats as having a series of methods:
Ruby is pure object-oriented language and everything appears to Ruby
as an object. Every value in Ruby is an object, even the most
primitive things: strings, numbers and even true and false. Even a
class itself is an object that is an instance of the Class class. This
chapter will take you through all the major functionalities related to
Object Oriented Ruby.
I write this because Ruby's object-orientated structure is much different than handling variables in the "traditional" sense -- in the simplest description, it means that Ruby presumes that objects are ALWAYS present (it just builds them from the NilClass), allowing you call "empty" data sets without running into "undeclared" issues
The problems occur when you try and run methods like .each on empty / nil objects. If you do this, errors like the one you alluded to occur; preventing you from being able to perform the functionality which you intended
--
Fix
Your error basically means you haven't declared your variable.
After seeing your code, the most obvious problem will be here:
#app/controllers/pages_controller.rb
Class PagesController < ApplicationController
def friends
# normally, you'd define your #instance_variables here
end
end
I see that your friends action does not declare your #users variable, which is required to perform the #users.each method. As recommended by Sam, the first step is to ensure you're able to declare this value, allowing you to loop through it as required:
#app/controllers/pages_controller.rb
Class PagesController < ApplicationController
def friends
#users = User.all
end
end