在单个节点上使用XPath返回所有节点中的元素 [英] Using XPath on single node returns elements in all nodes

问题描述

我正在解析看起来像这样的XML文档:

I am parsing an XML doc that looks something like this:

<MyBook>
   <title>Favorite Poems</title>
   <issn>123-456</issn>
   <pages>45</pages>
</MyBook>
<MyBook>
   <title>Chocolate Desserts</title>
   <issn>654-098</issn>
   <pages>100</pages>
</MyBook>
<MyBook>
   <title>Jabberwocky</title>
   <issn>454-545</issn>
   <pages>19</pages>
</MyBook>

我使用xpath拉出MyBook节点并像这样遍历它们:

I use xpath to pull out the MyBook nodes and iterate through them like so:

xmldoc.xpath("//MyBook").each do |node|
   mytitle=node.xpath("//title").text
   puts mytitle
end

输出看起来像这样:

Favorite PoemsChocolateDessertsJabberwocky
Favorite PoemsChocolateDessertsJabberwocky
Favorite PoemsChocolateDessertsJabberwocky

好像该节点实际上是整个xmldoc.但是，如果我打印出迭代器中的节点，则每次都达到我的期望时，就只有一个MyBook节点.我需要能够连续地从每个节点中拉出子节点，而不是整个文档中所有相同类型的子节点.我在做什么错了?

as if the node is really the whole xmldoc. However if I print out the node within the iterator, each time it is what I expect, just a single MyBook node. I need to be able to pull out the child nodes from each node successively, not all of the same kind of child node from the whole document. What am I doing wrong?

推荐答案

使用//title时，它将搜索从文档根部开始的所有<title>元素.只需使用title查找子标题，或者使用.//title(即使它们嵌套在其他元素中)也可以查找子标题.

When you use //title this searches for all <title> elements starting at the root of the document. Use either simply title to find child titles, or .//title if you want to find titles even if they are nested inside of other elements.

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