XPath与属性值上的正则表达式匹配

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为了破解这个问题,我已经搜索并修整了几个小时,但我仍然遇到问题.我有以下XML数据:

<game id="2009/05/02/arimlb-milmlb-1" pk="244539">
  <team id="109" name="Arizona" home_team="false">
    <event number="9" inning="1" description="Felipe Lopez doubles to left fielder Chris Duffy.  "/>
    <event number="15" inning="1" description="Augie Ojeda flies out to center fielder Mike Cameron.  "/>
    <event number="23" inning="1" description="Chad Tracy doubles to right fielder Joe Sanchez.  "/>
    <event number="52" inning="2" description="Mark Reynolds lines out to left fielder Chris Duffy.  "/>
    <!-- more data here -->
  </team>
</game>

我试图在description属性的值中获取包含文本"double"的事件节点的总数.这是我到目前为止所尝试的,无济于事(irb抛出错误):

"/game/team/event/@description[matches(.,' doubles ')]"

因为我只是想匹配description属性值的一个片段,所以可以使用XPath 2.0函数'匹配',对吗？如果是这样,我做错了什么？

在此先感谢您的帮助!

Answer 1

我试图在description属性的值中获取包含文本"double"的事件节点的总数.

matches()是标准的XPath 2.0功能.它在XPath 1.0中不可用.

你可以使用:

count(/*/*/event[contains(@description, ' doubles ')])

为了验证这一点,这里是一个小的XSLT转换,它只输出在提供的XML文档上评估上述XPath表达式的结果:

<xsl:stylesheet version="1.0"
 xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
 <xsl:output method="text"/>


 <xsl:template match="/">
  <xsl:value-of select=
  "count(/*/*/event[contains(@description, ' doubles ')])"/>
 </xsl:template>
</xsl:stylesheet>

当此转换应用于提供的XML文档时:

<game id="2009/05/02/arimlb-milmlb-1" pk="244539">
    <team id="109" name="Arizona" home_team="false">
        <event number="9" inning="1" description="Felipe Lopez doubles to left fielder Chris Duffy.  "/>
        <event number="15" inning="1" description="Augie Ojeda flies out to center fielder Mike Cameron.  "/>
        <event number="23" inning="1" description="Chad Tracy doubles to right fielder Joe Sanchez.  "/>
        <event number="52" inning="2" description="Mark Reynolds lines out to left fielder Chris Duffy.  "/>
        <!-- more data here -->
    </team>
</game>

产生了想要的正确结果:

2

Answer 2

请尝试以下变体:

/game/team/event[matches(@description, ' doubles ')]/@description

/game/team/event[matches(@description, '^.*?doubles.*$')]/@description

/game/team/event[contains(@description, ' doubles ')]/@description