Question

我正在尝试搜索有关网站新专辑发布的信息，我正在通过Nokogiri处理这个问题。我们的想法是创建一个包含类似项目的漂亮数组

[ 
  0 => ['The Wall', 'Pink Floyd', '1979'], 
  1 => ['Led Zeppelin I', 'Led Zeppelin', '1969']
 ]

这是我目前的代码。我是一个完全红宝石的新手，所以任何建议都会非常感激。

@events = Array.new()
# for every date we encounter
doc.css("#main .head_type_1").each do |item|

  date = item.text

  # get every albumtitle
  doc.css(".albumTitle").each_with_index do |album, index|
    album = album.text
    @events[index]['album'] = album
    @events[index]['release_date'] = date
  end

  #get every artistname
  doc.css(".artistName").each do |artist|
    artist = artist.text
    @events[index]['artist'] = artist
  end

end

puts @events

P.S。我试图抓取的页面格式有点奇怪：

<tr><th class="head_type_1">20 October 1989</th></tr>
<tr><td class="artistName">Jean Luc-Ponty</td><td class="albumTitle">Some example album</td></tr>
<tr><td class="artistName">Some Other Artist</td><td class="albumTitle">Some example album</td></tr>
<tr><td class="artistName">Some Other Artist</td><td class="albumTitle">Some example album</td></tr>
<tr><th class="head_type_1">29 October 1989</th></tr>
<tr><td class="artistName">Some Other Artist</td><td class="albumTitle">Some example album</td></tr>

当我尝试在ruby解释器中运行它时，我得到以下错误：

get_events.rb:25:in `block (2 levels) in <main>': undefined method `[]=' for nil:NilClass (NoMethodError)
from /Users/adrian/.rvm/gems/ruby-1.9.3-p286/gems/nokogiri-1.5.5/lib/nokogiri/xml/node_set.rb:239:in `block in each'
from /Users/adrian/.rvm/gems/ruby-1.9.3-p286/gems/nokogiri-1.5.5/lib/nokogiri/xml/node_set.rb:238:in `upto'
from /Users/adrian/.rvm/gems/ruby-1.9.3-p286/gems/nokogiri-1.5.5/lib/nokogiri/xml/node_set.rb:238:in `each'
from get_events.rb:23:in `each_with_index'
from get_events.rb:23:in `block in <main>'
from /Users/adrian/.rvm/gems/ruby-1.9.3-p286/gems/nokogiri-1.5.5/lib/nokogiri/xml/node_set.rb:239:in `block in each'
from /Users/adrian/.rvm/gems/ruby-1.9.3-p286/gems/nokogiri-1.5.5/lib/nokogiri/xml/node_set.rb:238:in `upto'
from /Users/adrian/.rvm/gems/ruby-1.9.3-p286/gems/nokogiri-1.5.5/lib/nokogiri/xml/node_set.rb:238:in `each'
from get_events.rb:18:in `<main>'

我该如何解决这个问题？

Answer 1

我无法绕过你的解决方案，但在玩了一下之后，我想出了这个。

require 'pp'
require 'nokogiri'

str = %Q{
<tr><th class="head_type_1">20 October 1989</th></tr>
<tr><td class="artistName">Jean Luc-Ponty</td><td class="albumTitle">Some album</td></tr>
<tr><td class="artistName">Some Other Artist</td><td class="albumTitle">Some album</td></tr>
<tr><td class="artistName">Some Other Artist</td><td class="albumTitle">Some album</td></tr>
<tr><th class="head_type_1">29 October 1989</th></tr>
<tr><td class="artistName">Some Other Artist</td><td class="albumTitle">Some album</td></tr>
}

doc = Nokogiri::HTML(str)
date = ""
result = []

doc.xpath("//tr").each do |tr|
  children = tr.children
  if children.first["class"] == "head_type_1"
    date = children.first.content
  else
    artist, album = children.map {|c| c.content}
    result << {album: album, artist: artist, date: date}
  end
end

pp result

输出：

[{:album=>"Some album", :artist=>"Jean Luc-Ponty", :date=>"20 October 1989"}, {:album=>"Some album", :artist=>"Some Other Artist", :date=>"20 October 1989"}, {:album=>"Some album", :artist=>"Some Other Artist", :date=>"20 October 1989"}, {:album=>"Some album", :artist=>"Some Other Artist", :date=>"29 October 1989"}]

不完全是你要求的，但也许更多的Ruby惯用，我相信如果需要你可以修改它。

Answer 2

索引变量在您的第二个each上未定义。

Ruby - 写入嵌套数组

2 个答案: