我收到了一个未定义的方法`name'，用于我的Rails项目的#error。我知道通过使用我的控制台进行双重检查为事件定义了名称，所以我不明白它为什么不加载。以下是我的一些代码：
应用显示：
<h1><%= @app.title %></h1>
<h5>App URL: <%= @app.url %></h5>
<h5>App User_id: <%= @app.user_id %></h5>
<br>
<h2> Events </h2>
<% @events.each do |event| %>
<div>
<%= event.name %><span class="badge"><%= event.count %></span>
</div>
<% end %>
<br>
<%= link_to "Edit", edit_app_path(@app), class: 'btn btn-success' %>
应用控制器：
class AppsController < ApplicationController
def create
@app = App.new(params.require(:app).permit(:title, :url))
@app.user_id = 1
if @app.save
flash[:notice] = "App was saved!"
redirect_to @app
else
flash[:error] = "There an error, oh noes!Please try again!"
render :new
end
end
def new
@app = App.new
end
def show
@app = App.find(params[:id])
@events = @app.events.group_by(&:name)
end
def index
@apps = App.all
end
def edit
@app = App.find(params[:id])
end
def update
@app = App.find(params[:id])
if @app.update_attributes(params.require(:app).permit(:title, :url))
flash[:notice] = "Application was updated."
redirect_to @app
else
flash[:error] = "There was an error saving the app. Please try again."
render :edit
end
end
def destroy
@app = App.find(params[:id])
if @app.destroy
flash[:notice] = "App was removed."
redirect_to @app
else
flash[:error] = "App couldn't be deleted. Try again."
redirect_to @app
end
respond_to do |format|
format.html
format.js
end
end
end
活动种子：
create_table "events", force: :cascade do |t|
t.integer "app_id"
t.string "name"
t.datetime "created_at", null: false
t.datetime "updated_at", null: false
end
应用型号：
class App < ActiveRecord::Base
belongs_to :user
has_many :events
end
完成错误日志：
Completed 500 Internal Server Error in 19ms
ActionView::Template::Error (undefined method `name' for #<Array:0x007fcc53394af0>):
6: <h2> Events </h2>
7: <% @events.each do |event| %>
8: <div>
9: <%= event.name %><span class="badge"><%= event.count %></span>
10: </div>
11: <% end %>
12: <br>
app/views/apps/show.html.erb:9:in `block in _app_views_apps_show_html_erb__2949113196422864311_70257764571040'
app/views/apps/show.html.erb:7:in `each'
app/views/apps/show.html.erb:7:in `_app_views_apps_show_html_erb__2949113196422864311_70257764571040'
Rendered /Users/ericpark/.rvm/gems/ruby-2.2.0/gems/actionpack-4.2.0/lib/action_dispatch/middleware/templates/rescues/_source.erb (7.1ms)
Rendered /Users/ericpark/.rvm/gems/ruby-2.2.0/gems/actionpack-4.2.0/lib/action_dispatch/middleware/templates/rescues/_trace.html.erb (4.1ms)
Rendered /Users/ericpark/.rvm/gems/ruby-2.2.0/gems/actionpack-4.2.0/lib/action_dispatch/middleware/templates/rescues/_request_and_response.html.erb (0.9ms)
Rendered /Users/ericpark/.rvm/gems/ruby-2.2.0/gems/actionpack-4.2.0/lib/action_dispatch/middleware/templates/rescues/template_error.html.erb within rescues/layout (71.2ms)
Rendered /Users/ericpark/.rvm/gems/ruby-2.2.0/gems/web-console-2.1.3/lib/web_console/templates/_markup.html.erb (0.7ms)
Rendered /Users/ericpark/.rvm/gems/ruby-2.2.0/gems/web-console-2.1.3/lib/web_console/templates/style.css.erb within layouts/inlined_string (0.7ms)
Rendered /Users/ericpark/.rvm/gems/ruby-2.2.0/gems/web-console-2.1.3/lib/web_console/templates/_inner_console_markup.html.erb within layouts/inlined_string (0.5ms)
Rendered /Users/ericpark/.rvm/gems/ruby-2.2.0/gems/web-console-2.1.3/lib/web_console/templates/_prompt_box_markup.html.erb within layouts/inlined_string (0.3ms)
Rendered /Users/ericpark/.rvm/gems/ruby-2.2.0/gems/web-console-2.1.3/lib/web_console/templates/console.js.erb within layouts/javascript (69.6ms)
Rendered /Users/ericpark/.rvm/gems/ruby-2.2.0/gems/web-console-2.1.3/lib/web_console/templates/main.js.erb within layouts/javascript (0.4ms)
Rendered /Users/ericpark/.rvm/gems/ruby-2.2.0/gems/web-console-2.1.3/lib/web_console/templates/error_page.js.erb within layouts/javascript (0.7ms)
Rendered /Users/ericpark/.rvm/gems/ruby-2.2.0/gems/web-console-2.1.3/lib/web_console/templates/index.html.erb (156.5ms)
答案 0 :(得分：1)
在这种情况下，简单的调试打印将揭示问题。如果您认为应该name @events，则@events未定义？您确定p @events是您认为的吗？
将@events = @app.events.group_by(&:name)
行添加到控制器，重试请求并阅读日志。对未来的建议。 ：）
问题从这里开始：
group_by我很确定group_by的输出是散列，其中键是不同的名称，值是所有具有相同名称的事件数组。 （当然，取决于<% @events.each do |event| %>
的具体实施方式）
event Event这里不是[name, [event1, event2, ...]]类的实例，而是一个双元素数组<% @events.each do |name, events| %>
<%= name %> <%= events.length %>
。你应该迭代这个嵌套的数组来获得真正的事件，它们有你想要的方法。
#define BOOST_SPIRIT_USE_PHOENIX_V3
#include <boost/filesystem/path.hpp>
#include <boost/utility/string_ref.hpp>
#include <boost/iostreams/device/mapped_file.hpp>
namespace io = boost::iostreams;
namespace fs = boost::filesystem;
class FastaReader {
public:
typedef std::pair<boost::string_ref, boost::string_ref> Entry;
typedef std::vector<Entry> Data;
private:
Data fV;
fs::path file;
public:
FastaReader(const fs::path & f);
~FastaReader();
const fs::path & getFile() const;
const Data::const_iterator begin() const;
const Data::const_iterator end() const;
private:
io::mapped_file_source mmap;
void parse();
};
#include <iomanip>
#include <boost/date_time/posix_time/posix_time.hpp>
#include <boost/filesystem/fstream.hpp>
#include <boost/filesystem/operations.hpp>
#include <boost/filesystem/path.hpp>
#include <boost/spirit/include/qi.hpp>
#include <boost/spirit/include/phoenix.hpp>
#include <boost/fusion/adapted/std_pair.hpp>
//#include "fastaReader.hpp"
#include <boost/iostreams/device/mapped_file.hpp>
using namespace std;
namespace fs = boost::filesystem;
namespace qi = boost::spirit::qi;
namespace pt = boost::posix_time;
namespace io = boost::iostreams;
namespace boost { namespace spirit { namespace traits {
template <typename It>
struct assign_to_attribute_from_iterators<boost::string_ref, It, void> {
static void call(It f, It l, boost::string_ref& attr) { attr = boost::string_ref { f, size_t(std::distance(f,l)) }; }
};
} } }
template <typename Iterator>
struct FastaGrammar : qi::grammar<Iterator, FastaReader::Data()> {
FastaGrammar() : FastaGrammar::base_type(fasta) {
using namespace qi;
using boost::phoenix::construct;
using boost::phoenix::begin;
using boost::phoenix::size;
entry = ('>' >> raw[ *~char_('\n') ] >> '\n' >> raw[ *~char_('>') ]);
fasta = *entry >> *eol >> eoi ;
BOOST_SPIRIT_DEBUG_NODES((fasta)(entry));
}
private:
qi::rule<Iterator, FastaReader::Data()> fasta;
qi::rule<Iterator, FastaReader::Entry()> entry;
};
FastaReader::FastaReader(const fs::path & f) : file(f), mmap(file.c_str()) {
parse();
}
FastaReader::~FastaReader() {}
const fs::path & FastaReader::getFile() const {
return this->file;
}
const FastaReader::Data::const_iterator FastaReader::begin() const {
return this->fV.cbegin();
}
const FastaReader::Data::const_iterator FastaReader::end() const {
return this->fV.cend();
}
void FastaReader::parse() {
if (this->file.empty()) throw std::runtime_error("FastaReader: No file specified.");
if (! fs::is_regular_file(this->file)) throw std::runtime_error(string("FastaReader: File not found: ") + this->file.string());
typedef char const* iterator_type;
typedef FastaGrammar<iterator_type> fastaGr;
static const fastaGr fG{};
try {
std::cerr << "Measuring: Parsing." << std::endl;
const pt::ptime startMeasurement = pt::microsec_clock::universal_time();
iterator_type first(mmap.data()), last(mmap.end());
qi::phrase_parse(first, last, fG, boost::spirit::ascii::space, this->fV);
const pt::ptime endMeasurement = pt::microsec_clock::universal_time();
pt::time_duration duration (endMeasurement - startMeasurement);
std::cerr << duration << std::endl;
} catch (std::exception const& e) {
cerr << "error message: " << e.what() << endl;
}
}
int main() {
FastaReader reader("input.txt");
for (auto& e : reader) std::cout << '>' << e.first << '\n' << e.second << "\n\n";
}
答案 1 :(得分：1)
@events是哈希，你必须像
一样迭代 <% @events.each do |event| %>
<div>
<%= event[0] %><span class="badge"><%= event[1].count %></span>
</div>
<% end %>