如何根据具体定义的同级内容获取同级的child

Question

我需要找到从以下 XML 数据中收集作家和艺术家信息的最佳方法。 comic 节点出现多次并包含一本漫画书的数据。

我无法根据他们的工作职能，作家，艺术家等来抓住合适的人。有时每本漫画书都有多个作家和艺术家。我的计划是 add/append 每个到一个列表。

因此，对于这本漫画书，我需要获取所有作家和艺术家的显示名称，但工作职能（例如作家）是人物姓名的同级。

这是我有的，但不起作用：

writer = []
penciler = []
doc.xpath('//comic').each do |main_element|
 main_element.xpath("mainsection/credits/credit/role[@id='dfWriter']").each do |n|
    writer << n.xpath('person/displayname').text
  end
  main_element.xpath("mainsection/credits/credit/role[@id='dfPenciler']").each do |n|
    penciler << n.xpath('person/displayname').text
  end
end

p "Writer(s): ",writer
p "Penciler(s): ",penciler

这是XML file/data:

<comic>
  <id>3398</id>
  <index>195</index>
  <mainsection>
    <title>Mind Games</title>
    <myrating>0</myrating>
    <myrating>
      <displayname>0</displayname>
      <sortname>0</sortname>
    </myrating>
    <pagecount>32</pagecount>
    <credits>
      <credit>
        <role id="dfWriter">Writer</role>
        <roleid>dfWriter</roleid>
        <person>
          <displayname>Will Pfeifer</displayname>
          <sortname>Pfeifer, Will</sortname>
          <lastname>Pfeifer</lastname>
          <firstname>Will</firstname>
        </person>
      </credit>
      <credit>
        <role id="dfWriter">Writer</role>
        <roleid>dfWriter</roleid>
        <person>
          <displayname>John Byrne</displayname>
          <sortname>Byrne, John</sortname>
          <lastname>Byrne</lastname>
          <firstname>John</firstname>
        </person>
      </credit>
      <credit>
        <role id="dfPenciler">Penciller</role>
        <roleid>dfPenciler</roleid>
        <person>
          <displayname>John Byrne</displayname>
          <sortname>Byrne, John</sortname>
          <lastname>Byrne</lastname>
          <firstname>John</firstname>
        </person>
      </credit>
    </credits>
  </mainsection>
</comic>

我的代码没有给我想要的结果。我找到了“Getting the siblings of a node with Nokogiri”，但我需要迭代并抓住每个兄弟姐妹。

我可以通过 <roleid>dfWriter</roleid> 或 <role id="dfWriter">Writer</role> 进行搜索，因为它们是相同的。

我的预期输出是：

Writer(s): Will Pfeifer, John Byrne 
Penciler(s): John Byrne

Answer 1

假设目标元素始终位于之后 role :

，您可以为此目的使用 XPath following-sibling 轴

doc.xpath('//comic').each do |main_element|
 main_element.xpath("mainsection/credits/credit/role[@id='dfWriter']").each do |n|
    writer << n.xpath('following-sibling::person/displayname').text
  end
  main_element.xpath("mainsection/credits/credit/role[@id='dfPenciler']").each do |n|
    penciler << n.xpath('following-sibling::person/displayname').text
  end
end

或者您可以首先遍历 credit 而不是 role :

doc.xpath('//comic').each do |main_element|
 main_element.xpath("mainsection/credits/credit[role/@id='dfWriter']").each do |n|
    writer << n.xpath('person/displayname').text
  end
  main_element.xpath("mainsection/credits/credit[role/@id='dfPenciler']").each do |n|
    penciler << n.xpath('person/displayname').text
  end
end

Answer 2

以下是我将如何执行此操作：

require 'nokogiri'

XML = <<EOT
<comic>
  <mainsection>
    <credits>
      <credit>
        <role id="dfWriter">Writer</role>
        <person>
          <displayname>Will Pfeifer</displayname>
        </person>
      </credit>
      <credit>
        <role id="dfWriter">Writer</role>
        <person>
          <displayname>John Byrne</displayname>
        </person>
      </credit>
      <credit>
        <role id="dfPenciler">Penciller</role>
        <person>
          <displayname>John Byrne</displayname>
        </person>
      </credit>
    </credits>
  </mainsection>
</comic>
EOT

doc = Nokogiri::XML(XML)

writers = doc.search("credits role[id='dfWriter']").map { |w| w.parent.at('displayname').text }
pencilers = doc.search("credits role[id='dfPenciler']").map { |n| n.parent.at('displayname').text }

puts "Writer(s): %s" % writers.join(', ')
puts "Penciler(s): %s" % pencilers.join(', ')

# >> Writer(s): Will Pfeifer, John Byrne
# >> Penciler(s): John Byrne

其中，当运行时，输出：

# >> Writer(s): Will Pfeifer, John Byrne
# >> Penciler(s): John Byrne

这个：

writers = doc.search("credits role[id='dfWriter']").map { |w| w.parent.at('displayname').text }
pencilers = doc.search("credits role[id='dfPenciler']").map { |n| n.parent.at('displayname').text }

可以干到：

writers, pencilers = %w(dfWriter dfPenciler).map { |s|
  doc.search("credits role[id='#{s}']").map { |w| w.parent.at('displayname').text }
}

我使用 CSS 提高可读性，at，returns 一个节点，当我想要文本而不是 xpath，returns一个节点集。

在 NodeSet 和 Node 上使用 text 之间的区别非常重要。考虑一下：

require 'nokogiri'

xml = <<EOT
<root>
  <displayname>Will Pfeifer</displayname>
  <displayname>John Byrne</displayname>
  <displayname>John Byrne</displayname>
</root>
EOT

doc = Nokogiri::XML(xml)
doc.search('displayname').class # => Nokogiri::XML::NodeSet
doc.search('displayname').text # => "Will PfeiferJohn ByrneJohn Byrne"

doc.at('displayname').class # => Nokogiri::XML::Element
doc.at('displayname').text # => "Will Pfeifer"

如果您希望 NodeSet 的所有文本都以易于使用的形式出现，则从每个节点中提取它：

doc.search('displayname').map(&:text) # => ["Will Pfeifer", "John Byrne", "John Byrne"]

如何根据具体定义的同级内容获取同级的child

How to get siblings' child according to specific defined sibling content

ruby

xml

nokogiri