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POWhy isn't this portion of HTML rendering and why do I get a undefined method `cardsets' for nil:NilClass in Rails?
 

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  1. POWhy isn't this portion of HTML rendering and why do I get a undefined method `cardsets' for nil:NilClass in Rails?
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    <p>I'm trying to add a flashcards(cardsets) feature in Rails and I'm having some problems implementing this as I'm getting an <code>undefined method</code>cardsets' for nil:NilClass` error </p> <p>I can get the page to render if I change: <code>&lt;% if @user.cardsets.any? %&gt;</code> to <code>&lt;% unless @cardsets.any? %&gt;</code> but the corresponding cardsets are being shown when I do this. Here is the html.erb code that is producing this error:</p> <pre><code>&lt;% provide(:title, "Flashcards") %&gt; &lt;h1&gt;Flashcards&lt;/h1&gt; &lt;div class="row"&gt; &lt;aside class="span3"&gt; &lt;%= render "shared/cardset_form" %&gt; &lt;/aside&gt; &lt;div class="span6"&gt; **&lt;% if @user.cardsets.any? %&gt;** &lt;h3&gt;Flashcard Sets (&lt;%= @user.cardsets.count %&gt;)&lt;/h3&gt; &lt;ol class="cardsets"&gt; &lt;% @user.cardsets.each do |cardset| %&gt; &lt;li&gt; &lt;span class="topic"&gt;&lt;%= link_to cardset.topic, show_cardset_path(cardset) %&gt;&lt;/span&gt; &lt;%= link_to "edit", edit_cardset_path(cardset) %&gt; &lt;%= render partial: "shared/delete_link", locals: {item: cardset} %&gt; &lt;/li&gt; &lt;% end %&gt; &lt;/ol&gt; &lt;% end %&gt; &lt;/div&gt; &lt;/div&gt; </code></pre> <p>I've starred the line that is producing the <code>undefined method</code>cardsets' for nil:NilClass` error. </p> <p>This is what's in my cardsets_controller.rb:</p> <pre><code>class CardsetsController &lt; ApplicationController before_action :signed_in_user, only: [:new, :index, :create, :edit, :destroy, :update] before_action :correct_user, only: [:edit, :update, :destroy] def index @cardsets = Cardset.all end def show @cardset = Cardset.find(params[:id]) end def create @cardset = current_user.cardsets.build(cardset_params) if @cardset.save flash[:success] = "A new set of flashcards have been created!" redirect_to @cardset else render "new" end end def new @cardset = Cardset.new end def edit end def update @cardset = Cardset.find(params[:id]) if @cardset.update_attributes(cardset_params) flash[:success] = "You've updated your flashcards!" redirect_to @cardset else render "edit" end end def destroy @cardset = Cardset.find(params[:id]) @cardset.delete redirect_to cardsets_path end private def cardset_params params.require(:cardset).permit(:topic, :description) end def correct_user @cardset = current_user.cardsets.find_by_id(params[:id]) redirect_to root_url if @cardset.nil? end end </code></pre> <p>Here is the code in my cardset.rb file:</p> <pre><code>class Cardset &lt; ActiveRecord::Base belongs_to :user validates :user_id, presence: true validates :topic, presence: true end </code></pre> <p>Here is the code in my user.rb file:</p> <pre><code>class User &lt; ActiveRecord::Base has_many :cardsets (...a bunch of other code...) end </code></pre> <p>If anyone could provide some help or suggestions on where I may be going wrong I'd greatly appreciate it! </p> <p>Thanks!</p>
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