TypeError：无法将数组转换为字符串

Posted 2023-02-23

【中文标题】TypeError：无法将数组转换为字符串

【英文标题】：TypeError: can't cast Array to string

【发布时间】：2014-10-24 12:06:21

【问题描述】：

我在尝试使用 Nokogiri 运行 rake 任务时遇到此错误。

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。

Rake 中止！ /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:intype_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:inmap' /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 _create_record' /Library/Ruby/Gems/2.0.0/gems/activerecord-4.1.5/lib/active_record/callbacks.rb:306:in block in _create_record' /Library/Ruby/Gems/2.0.0/gems/activesupport-4.1.5/lib/active_support/callbacks.rb:82:in run_callbacks' /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 _create_record' /Library/Ruby/Gems/2.0.0/gems/activerecord-4.1.5/lib/active_record/persistence.rb:482:in create_or_update' /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 run_callbacks' /Library/Ruby/Gems/2.0.0/gems/activerecord-4.1.5/lib/active_record/callbacks.rb:302:in create_or_update' /Library/Ruby/Gems/2.0.0/gems/activerecord-4.1.5/lib/active_record/persistence.rb:103:in save' /Library/Ruby/Gems/2.0.0/gems/activerecord-4.1.5/lib/active_record/validations.rb:51:in save' /Library/Ruby/Gems/2.0.0/gems/activerecord-4.1.5/lib/active_record/attribute_methods/dirty.rb:21:in save' /Library/Ruby/Gems/2.0.0/gems/activerecord-4.1.5/lib/active_record/transactions.rb:268:in block (2 levels) in save' /Library/Ruby/Gems/2.0.0/gems/activerecord-4.1.5/lib/active_record/transactions.rb:329:inblock in 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 in transaction' /Library/Ruby/Gems/2.0.0/gems/activerecord-4.1.5/lib/active_record/connection_adapters/abstract/database_statements.rb:209: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 transaction' /Library/Ruby/Gems/2.0.0/gems/activerecord-4.1.5/lib/active_record/transactions.rb:208:intransaction' /Library/Ruby/Gems/2.0.0/gems/activerecord-4.1.5/lib/active_record/transactions.rb:326:in with_transaction_returning_status' /Library/Ruby/Gems/2.0.0/gems/activerecord-4.1.5/lib/active_record/transactions.rb:268:inblock in save' /Library/Ruby/Gems/2.0.0/gems/activerecord-4.1.5/lib/active_record/transactions.rb:283:in rollback_active_record_state!' /Library/Ruby/Gems/2.0.0/gems/activerecord-4.1.5/lib/active_record/transactions.rb:267:insave' /Library/Ruby/Gems/2.0.0/gems/activerecord-4.1.5/lib/active_record/persistence.rb:34:in create' /Users/Kcummings/Sites/rvm_tests/lib/tasks/tops.rake:24:in block (3 级) in ' /Users/Kcummings/Sites/rvm_tests/lib/tasks/tops.rake:23:in each' /Users/Kcummings/Sites/rvm_tests/lib/tasks/tops.rake:23:inblock (2 水平）在' /Library/Ruby/Gems/2.0.0/gems/rake-10.3.2/lib/rake/task.rb:240:in call' /Library/Ruby/Gems/2.0.0/gems/rake-10.3.2/lib/rake/task.rb:240:in block 正在执行' /Library/Ruby/Gems/2.0.0/gems/rake-10.3.2/lib/rake/task.rb:235:in each' /Library/Ruby/Gems/2.0.0/gems/rake-10.3.2/lib/rake/task.rb:235:in 执行' /Library/Ruby/Gems/2.0.0/gems/rake-10.3.2/lib/rake/task.rb:179: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 mon_synchronize' /Library/Ruby/Gems/2.0.0/gems/rake-10.3.2/lib/rake/task.rb:172:in invoke_with_call_chain' /Library/Ruby/Gems/2.0.0/gems/rake-10.3.2/lib/rake/task.rb:165:in invoke' /Library/Ruby/Gems/2.0.0/gems/rake-10.3.2/lib/rake/application.rb:150:in invoke_task' /Library/Ruby/Gems/2.0.0/gems/rake-10.3.2/lib/rake/application.rb:106:in block (2 个级别) in top_level' /Library/Ruby/Gems/2.0.0/gems/rake-10.3.2/lib/rake/application.rb:106:in each' /Library/Ruby/Gems/2.0.0/gems/rake-10.3.2/lib/rake/application.rb:106:in block in top_level' /Library/Ruby/Gems/2.0.0/gems/rake-10.3.2/lib/rake/application.rb:115:in run_with_threads' /Library/Ruby/Gems/2.0.0/gems/rake-10.3.2/lib/rake/application.rb:100:in top_level' /Library/Ruby/Gems/2.0.0/gems/rake-10.3.2/lib/rake/application.rb:78:in block in run' /Library/Ruby/Gems/2.0.0/gems/rake-10.3.2/lib/rake/application.rb:176:in standard_exception_handling' /Library/Ruby/Gems/2.0.0/gems/rake-10.3.2/lib/rake/application.rb:75:in run' /Library/Ruby/Gems/2.0.0/gems/rake-10.3.2/bin/rake:33:in' /usr/bin/rake:23:in load' /usr/bin/rake:23:in'

编辑：TOPS TABLE SCHEMA

    ActiveRecord::Schema.define(version: 20140824150641) do

      create_table "tops", force: true do |t|
        t.string   "brand"
        t.string   "description"
        t.string   "image"
        t.decimal  "price"
        t.datetime "created_at"
        t.datetime "updated_at"
        t.string   "url"
      end
end

【问题讨论】：

发布您的 tops 表架构

【参考方案1】：

似乎您在表tops 中有description 字段为'varchar' 或string，但是您正在尝试在其中存储数组。

您需要将description 字段的数据类型更改为text，然后将值更改为serialize，然后再尝试存储它。

生成新的迁移文件并在终端上运行它：

rails g migration change_desc_in_my_tops

当您使用 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

现在尝试运行您的 rake 任务。希望对你有帮助。

注意：您应该使用单数型号名称。您的Tops 模型可能是Top。它在使用关联时避免了混淆，并且遵循约定。

【讨论】：

太棒了！非常感谢

【参考方案2】：

您将price 设置为一个数组（而不是称其为prices），这可能是您下面的错字的一个促成因素

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

您正在分配您正在迭代的数组，而不是正在生成的单个元素。