字符串无法强制转换为Fixnum（在content_tag中的方法内调用循环）

Question

我无法弄清楚为什么以下生成“字符串无法强制进入Fixnum”。

有什么想法吗？

  def branch_image
    image_tag("24white/branch.png")
  end

  def spacing_images
    i = 2
    i.times do
      image_tag("24white/blank.png")
    end
  end

  def insert_branch(prefix, type)
    content_tag(:li, spacing_images + branch_image + name_in_browser(prefix, type))
  end

  def name_in_browser(prefix, type)
     prefix + ": “" + truncate(type.name, :length => 20) + "”"
  end

如果我按如下方式编辑insert_branch，整个包工作正常：

  def insert_branch(prefix, type)
    content_tag(:li, branch_image + name_in_browser(prefix, type))
  end

在我粘贴到以下点的跟踪中，app/helpers/application_helper.rb:31为def insert_branch(prefix, type)。

（显然最终游戏是在某处计算i，但在我开始工作之前，我只是为它分配一个值。）

非常感谢，

史蒂芬。

app/helpers/application_helper.rb:31:in `+'
app/helpers/application_helper.rb:31:in `insert_branch'
app/views/partials/_project_browser.haml:8
/Library/Ruby/Gems/1.8/gems/actionpack-2.2.2/lib/action_view/renderable.rb:39:in `send'
/Library/Ruby/Gems/1.8/gems/actionpack-2.2.2/lib/action_view/renderable.rb:39:in `render'
/Library/Ruby/Gems/1.8/gems/actionpack-2.2.2/lib/action_view/renderable_partial.rb:20:in `render'
/Library/Ruby/Gems/1.8/gems/actionpack-2.2.2/lib/action_controller/benchmarking.rb:26:in `benchmark'
/Library/Ruby/Gems/1.8/gems/activesupport-2.2.2/lib/active_support/core_ext/benchmark.rb:8:in `realtime'
/Library/Ruby/Gems/1.8/gems/actionpack-2.2.2/lib/action_controller/benchmarking.rb:26:in `benchmark'
/Library/Ruby/Gems/1.8/gems/actionpack-2.2.2/lib/action_view/renderable_partial.rb:19:in `render'
/Library/Ruby/Gems/1.8/gems/actionpack-2.2.2/lib/action_view/template.rb:73:in `render_template'
/Library/Ruby/Gems/1.8/gems/actionpack-2.2.2/lib/action_view/renderable_partial.rb:45:in `render_partial'
/Library/Ruby/Gems/1.8/gems/actionpack-2.2.2/lib/action_view/partials.rb:152:in `render_partial'
/Library/Ruby/Gems/1.8/gems/actionpack-2.2.2/lib/action_view/base.rb:258:in `render_without_haml'
/Library/Ruby/Gems/1.8/gems/haml-2.2.3/lib/haml/helpers/action_view_mods.rb:11:in `render'
/Library/Ruby/Gems/1.8/gems/haml-2.2.3/lib/haml/helpers.rb:96:in `non_haml'
/Library/Ruby/Gems/1.8/gems/haml-2.2.3/lib/haml/helpers/action_view_mods.rb:11:in `render'
app/views/layouts/application.html.haml:31
/Library/Ruby/Gems/1.8/gems/actionpack-2.2.2/lib/action_view/renderable.rb:39:in `send'
/Library/Ruby/Gems/1.8/gems/actionpack-2.2.2/lib/action_view/renderable.rb:39:in `render'
/Library/Ruby/Gems/1.8/gems/actionpack-2.2.2/lib/action_view/template.rb:73:in `render_template'
/Library/Ruby/Gems/1.8/gems/actionpack-2.2.2/lib/action_view/base.rb:256:in `render_without_haml'
/Library/Ruby/Gems/1.8/gems/haml-2.2.3/lib/haml/helpers/action_view_mods.rb:13:in `render'
/Library/Ruby/Gems/1.8/gems/actionpack-2.2.2/lib/action_view/base.rb:371:in `_render_with_layout'
/Library/Ruby/Gems/1.8/gems/actionpack-2.2.2/lib/action_view/base.rb:254:in `render_without_haml'
/Library/Ruby/Gems/1.8/gems/haml-2.2.3/lib/haml/helpers/action_view_mods.rb:13:in `render'
/Library/Ruby/Gems/1.8/gems/actionpack-2.2.2/lib/action_controller/base.rb:1174:in `render_for_file'
/Library/Ruby/Gems/1.8/gems/actionpack-2.2.2/lib/action_controller/base.rb:905:in `render_without_benchmark'
/Library/Ruby/Gems/1.8/gems/actionpack-2.2.2/lib/action_controller/benchmarking.rb:51:in `render'
/Library/Ruby/Gems/1.8/gems/activesupport-2.2.2/lib/active_support/core_ext/benchmark.rb:8:in `realtime'
/Library/Ruby/Gems/1.8/gems/actionpack-2.2.2/lib/action_controller/benchmarking.rb:51:in `render'
/Library/Ruby/Gems/1.8/gems/actionpack-2.2.2/lib/action_controller/mime_responds.rb:135:in `send'
/Library/Ruby/Gems/1.8/gems/actionpack-2.2.2/lib/action_controller/mime_responds.rb:135:in `custom'
/Library/Ruby/Gems/1.8/gems/actionpack-2.2.2/lib/action_controller/mime_responds.rb:164:in `call'
/Library/Ruby/Gems/1.8/gems/actionpack-2.2.2/lib/action_controller/mime_responds.rb:164:in `respond'
/Library/Ruby/Gems/1.8/gems/actionpack-2.2.2/lib/action_controller/mime_responds.rb:158:in `each'
/Library/Ruby/Gems/1.8/gems/actionpack-2.2.2/lib/action_controller/mime_responds.rb:158:in `respond'
/Library/Ruby/Gems/1.8/gems/actionpack-2.2.2/lib/action_controller/mime_responds.rb:107:in `respond_to'
app/controllers/projects_controller.rb:17:in `show'
/Library/Ruby/Gems/1.8/gems/actionpack-2.2.2/lib/action_controller/base.rb:1253:in `send'
/Library/Ruby/Gems/1.8/gems/actionpack-2.2.2/lib/action_controller/base.rb:1253:in `perform_action_without_filters'
/Library/Ruby/Gems/1.8/gems/actionpack-2.2.2/lib/action_controller/filters.rb:617:in `call_filters'
/Library/Ruby/Gems/1.8/gems/actionpack-2.2.2/lib/action_controller/filters.rb:610:in `perform_action_without_benchmark'
/Library/Ruby/Gems/1.8/gems/actionpack-2.2.2/lib/action_controller/benchmarking.rb:68:in `perform_action_without_rescue'
/Library/Ruby/Gems/1.8/gems/actionpack-2.2.2/lib/action_controller/benchmarking.rb:68:in `perform_action_without_rescue'
/Library/Ruby/Gems/1.8/gems/actionpack-2.2.2/lib/action_controller/rescue.rb:136:in `perform_action_without_caching'
/Library/Ruby/Gems/1.8/gems/actionpack-2.2.2/lib/action_controller/caching/sql_cache.rb:13:in `perform_action'
/Library/Ruby/Gems/1.8/gems/activerecord-2.2.2/lib/active_record/connection_adapters/abstract/query_cache.rb:34:in `cache'
/Library/Ruby/Gems/1.8/gems/activerecord-2.2.2/lib/active_record/query_cache.rb:8:in `cache'
/Library/Ruby/Gems/1.8/gems/actionpack-2.2.2/lib/action_controller/caching/sql_cache.rb:12:in `perform_action'
/Library/Ruby/Gems/1.8/gems/actionpack-2.2.2/lib/action_controller/base.rb:524:in `send'
/Library/Ruby/Gems/1.8/gems/actionpack-2.2.2/lib/action_controller/base.rb:524:in `process_without_filters'
/Library/Ruby/Gems/1.8/gems/actionpack-2.2.2/lib/action_controller/filters.rb:606:in `process_without_session_management_support'
/Library/Ruby/Gems/1.8/gems/actionpack-2.2.2/lib/action_controller/session_management.rb:134:in `sass_old_process'
/Library/Ruby/Gems/1.8/gems/haml-2.2.3/lib/sass/plugin/rails.rb:19:in `process'
/Library/Ruby/Gems/1.8/gems/actionpack-2.2.2/lib/action_controller/base.rb:392:in `process'
/Library/Ruby/Gems/1.8/gems/mongrel-1.1.5/lib/mongrel/rails.rb:76:in `process'
/Library/Ruby/Gems/1.8/gems/mongrel-1.1.5/lib/mongrel/rails.rb:74:in `synchronize'
/Library/Ruby/Gems/1.8/gems/mongrel-1.1.5/lib/mongrel/rails.rb:74:in `process'
/Library/Ruby/Gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:159:in `process_client'
/Library/Ruby/Gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:158:in `each'
/Library/Ruby/Gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:158:in `process_client'
/Library/Ruby/Gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:in `run'
/Library/Ruby/Gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:in `initialize'
/Library/Ruby/Gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:in `new'
/Library/Ruby/Gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:in `run'
/Library/Ruby/Gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:268:in `initialize'
/Library/Ruby/Gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:268:in `new'
/Library/Ruby/Gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:268:in `run'
/Library/Ruby/Gems/1.8/gems/mongrel-1.1.5/lib/mongrel/configurator.rb:282:in `run'
/Library/Ruby/Gems/1.8/gems/mongrel-1.1.5/lib/mongrel/configurator.rb:281:in `each'
/Library/Ruby/Gems/1.8/gems/mongrel-1.1.5/lib/mongrel/configurator.rb:281:in `run'
/Library/Ruby/Gems/1.8/gems/mongrel-1.1.5/bin/mongrel_rails:128:in `run'
/Library/Ruby/Gems/1.8/gems/mongrel-1.1.5/lib/mongrel/command.rb:212:in `run'
/Library/Ruby/Gems/1.8/gems/mongrel-1.1.5/bin/mongrel_rails:281
/Library/Ruby/Gems/1.8/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:142:in `load_without_new_constant_marking'
/Library/Ruby/Gems/1.8/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:142:in `load'
/Library/Ruby/Gems/1.8/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:521:in `new_constants_in'
/Library/Ruby/Gems/1.8/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:142:in `load'
/Library/Ruby/Gems/1.8/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:153:in `require'
/Library/Ruby/Gems/1.8/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:521:in `new_constants_in'
/Library/Ruby/Gems/1.8/gems/activesupport-2.2.2/lib/active_support/dependencies.rb:153:in `require'

Answer 1

times会返回您发送给它的号码，因此您说2 + "24white/branch.png" + name_in_browser(prefix, type)。我认为您希望将spacing_images实施为image_tag("24white/blank.png") * 2。

Answer 2

问题是times正在返回调用它的数字，因此spacing_images返回相同的值。试试这个：

def spacing_images
  returning([]) do |images|
    3.times { images << helper.image_tag("24white/dot.png") }
  end.join(' ')
end

Answer 3

我很确定错误不是来自之前的代码片段，我无法在控制台（脚本/控制台）中重现这种情况：

i = 3
i.times do
  helper.image_tag("24white/dot.png")
end
#<img alt="Dot" src="/images/24white/dot.png" />
#<img alt="Dot" src="/images/24white/dot.png" />
#<img alt="Dot" src="/images/24white/dot.png" />
#=> 3

问题很可能出在代码的其他部分。