Hiding the entire column from a table in a rails view - ruby-on-rails

Question

Actually I would like to hide all the columns from a table in rails view, if those columns contains no data i.e., zero.
Secondly, I want to delete the respective row completely if quantity == 0.
Find the screenshot for better understanding as below;
screenshot.png
index.html.erb
<div class="col-md-10 col-md-offset-1">
<div class="table-responsive myTable">
<table class="table listing text-center">
<tr class="tr-head">
<td>DESCRIPTION</td>
<td>COLOR</td>
<td>QUANTITY</td>
<td>RETAIL PRICE</td>
<td>TOTAL AMOUNT</td>
<td>CARTON NO</td>
<td>CUSTOMER 1</td>
<td>CUSTOMER 2</td>
<td>ACTUAL QUANTITY</td>
</tr>
<% #purchases.each do |purchase| %>
<tr class="tr-<%= cycle('odd', 'even') %>">
<td class="col-2"><%= purchase.description %></td>
<td class="col-1"><%= purchase.color %></td>
<td class="col-2"><%= purchase.quantity %></td>
<td class="col-2"><%= number_with_precision(purchase.rprice, :delimiter => ",", :precision => 2) %></td>
<td class="col-2"><%= number_with_precision(purchase.tamount, :delimiter => ",", :precision => 2) %></td>
<td class="col-2"><%= purchase.cartonno %></td>
<td class="col-2"><%= purchase.cus1 %></td>
<td class="col-2"><%= purchase.cus2 %></td>
<td class="col-2"><%= tquantity = purchase.quantity - purchase.cus1 - purchase.cus2 %></td>
</tr>
<% end %>
</table>
</div>
</div>
</div>
purchases_controller.rb
class PurchasesController < ApplicationController
before_action :set_purchase, only: [:show, :edit, :update, :destroy]
# GET /Stockings
# GET /deldetails.json
def index
##purchases = Purchase.all
#purchases = Purchase.where("tquantity !=?", 0)
end
def import
Purchase.import(params[:file])
redirect_to purchases_url, notice: "Purchases imported."
end
# GET /purchases/1
# GET /purchases/1.json
def show
end
# GET /purchases/new
def new
#purchase = Purchase.new
end
# GET /purchases/1/edit
def edit
end
# POST /purchases
# POST /purchases.json
def create
#purchase = Purchase.new(purchase_params)
respond_to do |format|
if #purchase.save
format.html { redirect_to #purchase, notice: 'Purchase was successfully created.' }
format.json { render :show, status: :created, location: #purchase }
else
format.html { render :new }
format.json { render json: #purchase.errors, status: :unprocessable_entity }
end
end
end
# PATCH/PUT /purchases/1
# PATCH/PUT /purchases/1.json
def update
respond_to do |format|
if #purchase.update(purchase_params)
format.html { redirect_to #purchase, notice: 'Purchase was successfully updated.' }
format.json { render :show, status: :ok, location: #purchase }
else
format.html { render :edit }
format.json { render json: #purchase.errors, status: :unprocessable_entity }
end
end
end
# DELETE /purchases/1
# DELETE /purchases/1.json
def destroy
#purchase.destroy
respond_to do |format|
format.html { redirect_to purchases_url, notice: 'Purchase was successfully destroyed.' }
format.json { head :no_content }
end
end
private
# Use callbacks to share common setup or constraints between actions.
def set_purchase
#purchase = Purchase.find(params[:id])
end
# Never trust parameters from the scary internet, only allow the white list through.
def purchase_params
params.require(:purchase).permit(:season, :category, :articleno, :description, :color, :quantity, :rprice, :tamount, :cartonno, :cus1, :cus2, :tquantity )
end
end
purchase.rb
class Purchase < ActiveRecord::Base
def self.import(file)
CSV.foreach(file.path, headers: true) do |row|
Purchase.create! row.to_hash
end
end
end
Do I need to go for if else or ternary operator for checking the for the columns if it is empty or not ?
Any suggestions are most welcome.
Thank you in advance.

Answer 1

you can add a condition in your view.
<% unless #purchases.collect{|p| p.cus2}.uniq == [0] %>
<td>CUSTOMER 2</td>
<% end %>
and
<% #purchases.each do |purchase| %>
<% unless purchase.quantity == 0 %>
<tr class="tr-<%= cycle('odd', 'even') %>">
<td class="col-2"><%= purchase.description %></td>
<td class="col-1"><%= purchase.color %></td>
<td class="col-2"><%= purchase.quantity %></td>
<td class="col-2"><%= number_with_precision(purchase.rprice, :delimiter => ",", :precision => 2) %></td>
<td class="col-2"><%= number_with_precision(purchase.tamount, :delimiter => ",", :precision => 2) %></td>
<td class="col-2"><%= purchase.cartonno %></td>
<td class="col-2"><%= purchase.cus1 %></td>
<% unless #purchases.collect{|p| p.cus2}.uniq == [0] %>
<td class="col-2"><%= purchase.cus2 %></td>
<% end %>
<td class="col-2"><%= tquantity = purchase.quantity - purchase.cus1 - purchase.cus2 %></td>
</tr>
<% end %>
<% end %>
and to remove row with 0 quantity the best thing is do not select those records having 0 quantity with in query.
#purchases = Purchase.where("quantity !=?", 0)
or alternatively I also have updated the view code which is less recommended.

Answer 2

I have understand your problem. But why are you taking those records inside the instance varible #purchases.
You should write a query or scope like so that will exclude the record which have the values zero inside the column.
Lets have a example like as below...
Class Purchase < ActiveRecord::Base
scope :exclude_zero_value_customers, -> { where('cus1 <> ? && cus2 <> ?', 0,0) }
end
Or you can hide it directly from the view as well, But in that case if you have thousands of records then also it will go one time with that loop as bwlow...
<% #purchases.each do |purchase| %>
<% if !purchase.cus1.zero? && !purchase.cus2.zero? %>
<tr class="tr-<%= cycle('odd', 'even') %>">
<td class="col-2"><%= purchase.description %></td>
<td class="col-1"><%= purchase.color %></td>
<td class="col-2"><%= purchase.quantity %></td>
<td class="col-2"><%= number_with_precision(purchase.rprice, :delimiter => ",", :precision => 2) %></td>
<td class="col-2"><%= number_with_precision(purchase.tamount, :delimiter => ",", :precision => 2) %></td>
<td class="col-2"><%= purchase.cartonno %></td>
<td class="col-2"><%= purchase.cus1 %></td>
<td class="col-2"><%= purchase.cus2 %></td>
<td class="col-2"><%= tquantity = purchase.quantity - purchase.cus1 - purchase.cus2 %></td>
</tr>
<% end %>
<% end %>