TypeError：无法将Array转换为字符串

时间：2014-08-30 19:13:00

标签： ruby-on-rails ruby nokogiri rake-task

尝试使用Nokogiri运行rake任务时出现此错误。

这是代码。

namespace :tops do
  desc "Get Tops Description"
  task get_description: :environment do
  require 'nokogiri'
  require 'open-uri'

 doc = Nokogiri::HTML(open("http://ceratoboutique.com/collections/tops"))

  price = Array.new 
  items = Array.new
  brands = Array.new
  sale_price = Array.new
  image = Array.new
  item_url = Array.new

  price = doc.xpath("//del").collect {|node| node.text.strip}
  items = doc.xpath("//div/a/h4").collect {|node| node.text.strip}
  brands = doc.xpath("//span[contains(@class,'vendor')]").collect {|node| node.text.strip}
  sale_price = doc.xpath("//span[contains(@class, 'price')]/text()").collect {|node| node.text.strip}
  image = doc.xpath("/div/a/img/@src").collect {|node| node.text.strip}
  item_url = doc.css('div.details a').map { |link| link['href'] }.collect 

  price.each do |prices|
      Tops.create(description: price)
    end
  end
end

这是完整的错误。

  耙子流产了！ TypeError：无法将Array转换为字符串   /Library/Ruby/Gems/2.0.0/gems/activerecord-4.1.5/lib/active_record/connection_adapters/abstract/quoting.rb:76:in type_cast' /Library/Ruby/Gems/2.0.0/gems/activerecord-4.1.5/lib/active_record/connection_adapters/sqlite3_adapter.rb:261:in type_cast'   /Library/Ruby/Gems/2.0.0/gems/activerecord-4.1.5/lib/active_record/connection_adapters/sqlite3_adapter.rb:295:in block in exec_query' /Library/Ruby/Gems/2.0.0/gems/activerecord-4.1.5/lib/active_record/connection_adapters/sqlite3_adapter.rb:294:in map'   /Library/Ruby/Gems/2.0.0/gems/activerecord-4.1.5/lib/active_record/connection_adapters/sqlite3_adapter.rb:294:in exec_query' /Library/Ruby/Gems/2.0.0/gems/activerecord-4.1.5/lib/active_record/connection_adapters/abstract/database_statements.rb:68:in exec_insert'   /Library/Ruby/Gems/2.0.0/gems/activerecord-4.1.5/lib/active_record/connection_adapters/abstract/database_statements.rb:95:in   insert' /Library/Ruby/Gems/2.0.0/gems/activerecord-4.1.5/lib/active_record/connection_adapters/abstract/query_cache.rb:14:in 插入”   /Library/Ruby/Gems/2.0.0/gems/activerecord-4.1.5/lib/active_record/relation.rb:64:in   insert' /Library/Ruby/Gems/2.0.0/gems/activerecord-4.1.5/lib/active_record/persistence.rb:502:in _ create_record”   /Library/Ruby/Gems/2.0.0/gems/activerecord-4.1.5/lib/active_record/attribute_methods/dirty.rb:87:in   {_ 1}}阻止_create_record'   /Library/Ruby/Gems/2.0.0/gems/activesupport-4.1.5/lib/active_support/callbacks.rb:82:in   _create_record' /Library/Ruby/Gems/2.0.0/gems/activerecord-4.1.5/lib/active_record/callbacks.rb:306:in _ create_record”   /Library/Ruby/Gems/2.0.0/gems/activerecord-4.1.5/lib/active_record/timestamp.rb:57:in   run_callbacks' /Library/Ruby/Gems/2.0.0/gems/activerecord-4.1.5/lib/active_record/callbacks.rb:306:in create_or_update”   /Library/Ruby/Gems/2.0.0/gems/activerecord-4.1.5/lib/active_record/callbacks.rb:302:in   _create_record' /Library/Ruby/Gems/2.0.0/gems/activerecord-4.1.5/lib/active_record/persistence.rb:482:in run_callbacks'   /Library/Ruby/Gems/2.0.0/gems/activerecord-4.1.5/lib/active_record/callbacks.rb:302:in   block in create_or_update' /Library/Ruby/Gems/2.0.0/gems/activesupport-4.1.5/lib/active_support/callbacks.rb:82:in 保存”   /Library/Ruby/Gems/2.0.0/gems/activerecord-4.1.5/lib/active_record/validations.rb:51:in   create_or_update' /Library/Ruby/Gems/2.0.0/gems/activerecord-4.1.5/lib/active_record/persistence.rb:103:in 保存”   /Library/Ruby/Gems/2.0.0/gems/activerecord-4.1.5/lib/active_record/transactions.rb:268:in save' /Library/Ruby/Gems/2.0.0/gems/activerecord-4.1.5/lib/active_record/attribute_methods/dirty.rb:21:in 阻止了with_transaction_returning_status'   /Library/Ruby/Gems/2.0.0/gems/activerecord-4.1.5/lib/active_record/connection_adapters/abstract/database_statements.rb:201:in   block (2 levels) in save' /Library/Ruby/Gems/2.0.0/gems/activerecord-4.1.5/lib/active_record/transactions.rb:329:in within_new_transaction”   /Library/Ruby/Gems/2.0.0/gems/activerecord-4.1.5/lib/active_record/connection_adapters/abstract/database_statements.rb:201:in   block in transaction' /Library/Ruby/Gems/2.0.0/gems/activerecord-4.1.5/lib/active_record/connection_adapters/abstract/database_statements.rb:209:in 交易”   /Library/Ruby/Gems/2.0.0/gems/activerecord-4.1.5/lib/active_record/transactions.rb:326:in transaction' /Library/Ruby/Gems/2.0.0/gems/activerecord-4.1.5/lib/active_record/transactions.rb:208:in阻止保存'   /Library/Ruby/Gems/2.0.0/gems/activerecord-4.1.5/lib/active_record/transactions.rb:283:in with_transaction_returning_status' /Library/Ruby/Gems/2.0.0/gems/activerecord-4.1.5/lib/active_record/transactions.rb:268:in save'   /Library/Ruby/Gems/2.0.0/gems/activerecord-4.1.5/lib/active_record/persistence.rb:34:in   'rollback_active_record_state!' /Library/Ruby/Gems/2.0.0/gems/activerecord-4.1.5/lib/active_record/transactions.rb:267:in阻止（3级）'   /Users/Kcummings/Sites/rvm_tests/lib/tasks/tops.rake:23:in create' /Users/Kcummings/Sites/rvm_tests/lib/tasks/tops.rake:24:in 块（2   水平）'   /Library/Ruby/Gems/2.0.0/gems/rake-10.3.2/lib/rake/task.rb:240:in   each' /Users/Kcummings/Sites/rvm_tests/lib/tasks/tops.rake:23:in阻止执行'   /Library/Ruby/Gems/2.0.0/gems/rake-10.3.2/lib/rake/task.rb:235:in   call' /Library/Ruby/Gems/2.0.0/gems/rake-10.3.2/lib/rake/task.rb:240:in 执行”   /Library/Ruby/Gems/2.0.0/gems/rake-10.3.2/lib/rake/task.rb:179:in   each' /Library/Ruby/Gems/2.0.0/gems/rake-10.3.2/lib/rake/task.rb:235:in mon_synchronize”   /Library/Ruby/Gems/2.0.0/gems/rake-10.3.2/lib/rake/task.rb:172:in   block in invoke_with_call_chain' /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/monitor.rb:211:in 调用”   /Library/Ruby/Gems/2.0.0/gems/rake-10.3.2/lib/rake/application.rb:150:in   top_level中invoke_with_call_chain' /Library/Ruby/Gems/2.0.0/gems/rake-10.3.2/lib/rake/task.rb:165:in 阻止（2个级别） 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编辑：TOPS TABLE SCHEMA 

load' /usr/bin/rake:23:in

2 个答案:

答案 0 :(得分：7)

似乎表description中的tops字段为“varchar”或string，但您尝试将数组存储在其中。

在尝试存储之前，您需要将description字段的数据类型更改为text，然后再将serialize更改为该值。

生成新的迁移文件并运行它，在您的终端上：

rails g migration change_desc_in_my_tops

在使用Rails 4时，请在迁移文件中添加以下代码：

class ChangeDescInTops < ActiveRecord::Migration
  def up
    change_column :tops, :description, :text
  end

  def down
    change_column :tops, :description, :string
  end
end

现在运行迁移：

rake db:migrate

将您的tops模型更新为：

class Tops < ActiveModel::Base
  serialize :description, Array
  ...
  ...
end

现在尝试运行你的rake任务。希望，它会帮助你。

注意：您应该使用单数型号名称。您的Tops模型可能是Top。它避免了使用关联时的混淆，它遵循惯例。

答案 1 :(得分：2)

你把price设置为一个数组（而不是称之为prices）让你很困惑，这可能是你输入错误的一个因素

price.each do |prices|
  Tops.create(description: price)
end

您正在分配正在迭代的数组，而不是正在生成的单个元素。

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