Question

我为此设置收到此错误。我的想法是该文件无法正常访问csv。我试图导入。我必须从一个csv导入，使用模型日期创建另一个csv。我在控制器和视图中放置什么来显示新的csv /操纵数据？基本上我怎样才能在模型中传递一个csv文件进行操作（orders.csv）并将其传递到另一个csv文件（redemption.csv）模型中的代码只是告诉模型以一定的方式计算orders.csv中的现有数字出口没有这个参数错误？

控制器（我真的不知道该怎么做）

class OrdersController < ApplicationController
  def index
    orders = Order.new
  end

  def redemptions
    orders = Order.new
  end
end

观点（对此也没有信心）

<h1>Chocolates</h1>
puts "#{order.purchased_chocolate_count}"
<%= link_to "CSV", orders_redemptions_path, :format => :csv %>

模型

require 'csv'

# Define an Order class to make it easier to store / calculate chocolate    tallies
class Order < ActiveRecord::Base

  module ChocolateTypes
    MILK      = 'milk'
    DARK      = 'dark'
    WHITE     = 'white'
    SUGARFREE = 'sugar free'
  end

  BonusChocolateTypes = {
    ChocolateTypes::MILK      => [ChocolateTypes::MILK, ChocolateTypes::SUGARFREE],
    ChocolateTypes::DARK      => [ChocolateTypes::DARK],
    ChocolateTypes::WHITE     => [ChocolateTypes::WHITE, ChocolateTypes::SUGARFREE],
    ChocolateTypes::SUGARFREE => [ChocolateTypes::SUGARFREE, ChocolateTypes::DARK]
  }

    # Ruby has this wacky thing called attr_reader that defines the available
    # operations that can be performed on class member variables from outside:
    attr_reader :order_value
    attr_reader :chocolate_price
    attr_reader :required_wrapper_count
    attr_reader :order_chocolate_type
    attr_reader :chocolate_counts

    def initialize(order_value, chocolate_price, required_wrapper_count, order_chocolate_type)
        @order_value            = order_value
        @chocolate_price        = chocolate_price
        @required_wrapper_count = required_wrapper_count
        @order_chocolate_type   = order_chocolate_type

        # Initialize a new hash to store the chocolate counts by chocolate type.
        # Set the default value for each chocolate type to 0
        @chocolate_counts = Hash.new(0);

        process
    end

    # Return the number of chocolates purchased
    def purchased_chocolate_count
        # In Ruby, division of two integer values returns an integer value,
        # so you don't have to floor the result explicitly
        order_value / chocolate_price
    end

    # Return the number of chocolate bonuses to award (which can include
    # multiple different chocolate types; see BonusChocolateTypes above)
    def bonus_chocolate_count
        (purchased_chocolate_count / required_wrapper_count).to_i
    end

    # Process the order:
    #   1. Add chocolate counts to the totals hash for the specified order type
    #   2. Add the bonus chocolate types awarded for this order
    def process
        chocolate_counts[order_chocolate_type] += purchased_chocolate_count

        bonus_chocolate_count.times do |i|
            BonusChocolateTypes[order_chocolate_type].each do |bonus_chocolate_type|
                chocolate_counts[bonus_chocolate_type] += 1
            end
        end
    end

    # Output the chocolate counts (including bonuses) for the order as an array
    # of strings suitable for piping to an output CSV
    def csv_data
        ChocolateTypes.constants.map do |output_chocolate_type|
            # Get the display string (lowercase)
            chocolate_key = ChocolateTypes.const_get(output_chocolate_type)
            chocolate_count = chocolate_counts[chocolate_key].to_i

            "#{chocolate_key} #{chocolate_count}"
        end
    end
  end


  # Create a file handle to the output file
  CSV.open("redemptions.csv", "wb") do |redemption_csv|

    # Read in the input file and store it as an array of lines
        input_lines = CSV.read("orders.csv")

    # Remove the first line from the input file (it just contains the CSV headers)
        input_lines.shift()

    input_lines.each do |input_line|
        order_value, chocolate_price, required_wrapper_count, chocolate_type = input_line

      # Correct the input values to the correct types
        order_value = order_value.to_f
        chocolate_price = chocolate_price.to_f
        required_wrapper_count = required_wrapper_count.to_i

        # Sanitize the chocolate type from the input line so that it doesn't
        # include any quotes or leading / trailing whitespace
        chocolate_type = chocolate_type.gsub(/[']/, '').strip

      order = Order.new(order_value, chocolate_price, required_wrapper_count, chocolate_type)
        order.process()

        puts order.purchased_chocolate_count

        # Append the order to the output file as a new CSV line
        output_csv << order.csv_data
    end
  end

Answer 1

在您的initialize方法中，您没有为参数提供默认值。

def initialize(order_value, chocolate_price, required_wrapper_count, order_chocolate_type)

当您尝试运行orders = Order.new时，预计会有四个参数而您尚未提供。

还有一个问题。对于正确的命名约定，您的本地变量名称应为order而不是orders。

要正确指定默认值，您可以查看here。

错误的参数数量（给定0，预期4）

1 个答案: