xml - XSLT 中的字频计数器

Question

我正在尝试在 XSLT 中制作一个词频计数器。我希望它使用停用词。我开始使用 Michael Kay's book .但是我很难让停用词起作用。

此代码适用于任何源 XML 文件。

<?xml version="1.0" encoding="iso-8859-1"?>
<xsl:stylesheet
   version="2.0"
   xmlns:xsl="http://www.w3.org/1999/XSL/Transform">

<xsl:output method="xml" indent="yes"/>

<xsl:template match="/">   
    <xsl:variable name="stopwords" select="'a about an are as at be by for from how I in is it of on or that the this to was what when where who will with'"/>
     <wordcount>
        <xsl:for-each-group group-by="." select="
            for $w in //text()/tokenize(., '\W+')[not(.=$stopwords)] return $w">
            <word word="{current-grouping-key()}" frequency="{count(current-group())}"/>
        </xsl:for-each-group>
     </wordcount>
</xsl:template>

</xsl:stylesheet>

我认为 not(.=$stopwords)是我的问题所在。但我不知道该怎么办。

此外，我将提示如何从外部文件加载停用词。

Answer 1

您的 $stopwords 变量现在是一个字符串；你希望它是一个字符串序列。您可以通过以下任一方式执行此操作:

将其声明更改为

<xsl:variable name="stopwords" 
  select="('a', 'about', 'an', 'are', 'as', 'at', 
           'be', 'by', 'for', 'from', 'how', 
           'I', 'in', 'is', 'it', 
           'of', 'on', 'or', 
           'that', 'the', 'this', 'to', 
           'was', 'what', 'when', 'where', 
           'who', 'will', 'with')"/>

将其声明更改为

<xsl:variable name="stopwords" 
  select="tokenize('a about an are as at 
                    be by for from how I in is it 
                    of on or that the this to was 
                    what when where who will with',
                    '\s+')"/>

从名为(例如)stoplist.xml 的外部 XML 文档中读取它，格式为

<stop-list>
  <p>This is a sample stop list [further description ...]</p>
  <w>a</w>
  <w>about</w>
  ...
</stop-list>

然后加载它，例如与

<xsl:variable name="stopwords"
  select="document('stopwords.xml')//w/string()"/>