Question

首先，这是来自my previous question的产卵。我已经发布了这个，因为the person whose answer I accepted in the original post建议我这样做，因为他觉得之前没有正确定义这个问题。这是尝试2：

我正试图从this webpage中获取信息。为清楚起见，以下是页面源块的选择：

<p class="titlestyle">ANT101H5 Introduction to Biological Anthropology and Archaeology 
                    <span class='distribution'>(SCI)</span></p> 
<span class='normaltext'> 
Anthropology is the global and holistic study of human biology and behaviour, and includes four subfields: biological anthropology, archaeology, sociocultural anthropology and linguistics. The material covered is  directed  to answering the question: What makes us human? This course is a survey of  biological  anthropology and  archaeology.  [<span class='Helpcourse'
        onMouseover="showtip(this,event,'24 Lectures')"
        onMouseout="hidetip()">24L</span>, <span class='Helpcourse'
        onMouseover="showtip(this,event,'12 Tutorials')"
        onMouseout="hidetip()">12T</span>]<br> 
<span class='title2'>Exclusion: </span><a href='javascript:OpenCourse("WEBCOURSENOTFOUND.html")'>ANT100Y5</a><br> 
<span class='title2'>Prerequisite: </span><a href='javascript:OpenCourse("WEBCOURSEANT102H5.pl?fv=1")'>ANT102H5</a><br>

从上面的示例块中，我想提取以下信息：

ANT101H5 Introduction to Biological Anthropology and Archaeology
Exclusion: ANT100Y5
Prerequisite: ANT102H5

我想从网页上获取所有此类信息（请记住，某些课程可能还有一个额外列出的“Corequisite”，或者根本没有列出任何前/后必需品或排除项。）

我一直在尝试为此任务编写适当的xpath表达式，但我似乎无法正确地完成它。

到目前为止，在Dimitre Novatchev的帮助下，我能够使用以下表达式：

sites = hxs.select("(//p[@class='titlestyle'])[2]/text()[1] | (//span[@class='title2'])[2]/text() | \
                    (//span[@class='title2'])[2]/following-sibling::a[1]/text() | (//span[@class='title2'])[3]/text() | \
                    (//span[@class='title2'])[3]/following-sibling::a[1]/text()")

但是，它产生以下输出，它似乎只获取页面上第一个课程的信息：

[{"desc": "ANT101H5 Introduction to Biological Anthropology and Archaeology \n                        "},
 {"desc": "Exclusion: "},
 {"desc": "ANT100Y5"},
 {"desc": "Prerequisite: "},
 {"desc": "ANT102H5"}]

为了绝对清楚，只有获得有关第一道菜的正确信息，此输出才是正确的。对于该网页上列出的所有课程，我需要正确的信息。

我太近了，但我似乎无法弄清楚最后一步。

我很感激任何帮助......提前谢谢

Answer 1

为所有课程选择相关数据所需的单个XPath表达式非常混乱，所以这里我采用另一种方法，可以使用（如果有必要的话）生成单个XPath表达式：

这个简单的XSLT转换：

<xsl:stylesheet version="1.0"
 xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
 <xsl:output omit-xml-declaration="yes" indent="yes"/>
 <xsl:strip-space elements="*"/>

 <xsl:template match="p[@class='titlestyle']">
  <xsl:text>&#xA;===================&#xA;</xsl:text>
  <xsl:value-of select="text()[1]"/>
 </xsl:template>

 <xsl:template match=
  "span/span[@class='title2'][not(position() >1)]">
   <xsl:text>&#xA;</xsl:text>
   <xsl:value-of select="."/>
   <xsl:value-of select="following-sibling::a[1]"/>

   <xsl:if test="not(following-sibling::a)">
    <xsl:value-of select="following-sibling::text()[1]"/>
   </xsl:if>
   <xsl:text>&#xA;</xsl:text>
 </xsl:template>
 <xsl:template match="text()"/>
</xsl:stylesheet>

在页面上应用时： http://www.utm.utoronto.ca/regcal/WEBLISTCOURSES1.html （整理成为格式良好的XML文档），生成想要的结果< /强>：

=================== Anthropology =================== ANT101H5 Introduction to Biological Anthropology and Archaeology Exclusion: ANT100Y5 =================== ANT102H5 Introduction to Sociocultural and Linguistic Anthropology Exclusion: ANT100Y5 =================== ANT200Y5 World Archaeology and Prehistory Prerequisite: 101H5 =================== ANT203Y5 Biological Anthropology Prerequisite: 101H5 =================== ANT204Y5 Sociocultural Anthropology Prerequisite: 101H5 =================== ANT205H5 Introduction to Forensic Anthropology Prerequisite: 101H5 =================== ANT206Y5 Culture and Communication: Introduction to Linguistic Anthropology Exclusion: ANT206H5 =================== ANT241Y5 Aboriginal Peoples of North America =================== ANT299Y5 Research Opportunity Program =================== ANT304H5 Anthropology and Aboriginal Peoples Exclusion: ANT304Y5 =================== ANT306H5 Forensic Anthropology Field School Prerequisite: ANT205H5 =================== ANT308H5 Case Studies in Archaeological Botany and Zoology Prerequisite: ANT200Y5 =================== ANT309H5 Southeast Asian Archaeology Prerequisite: ANT200Y5 =================== ANT310H5 Complex Societies Prerequisite: ANT200Y5 =================== ANT312H5 Archaeological Analysis Prerequisite: ANT200Y5 =================== ANT313H5 China, Korea and Japan in Prehistory Prerequisite: ANT200Y5 =================== ANT314H5 Archaeological Theory Exclusion: ANT411H5 =================== ANT316H5 South Asian Archaeology Prerequisite: ANT200Y5 =================== ANT317H5 Archaeology of Eastern North America Prerequisite: ANT200Y5 =================== ANT318H5 Archaeological Fieldwork Prerequisite: ANT200Y5 =================== ANT320H5 Archaeological Approaches to Technology Prerequisite: ANT200Y5 =================== ANT322H5 Anthropology of Youth Culture Exclusion: ANT204Y5 =================== ANT327H5 Agricultural Origins: The Second Revolution Prerequisite: ANT200Y5 =================== ANT331H5 The Biology of Human Sexuality Exclusion: ANT330H5 =================== ANT332H5 Human Origins Exclusion: ANT332Y5 =================== ANT333H5 Human Origins II Exclusion: ANT332Y5 =================== ANT334H5 Human Osteology Exclusion: ANT334Y5 =================== ANT335H5 Anthropology of Gender Exclusion: ANT331Y5 =================== ANT336H5 Molecular Anthropology Prerequisite: ANT203Y5 =================== ANT338H5 Laboratory Methods in Biological Anthropology Prerequisite: ANT203Y5 =================== ANT339Y5 Human Adaptation through Biological and Cultural Means Prerequisite: ANT203Y5 =================== ANT340H5 Osteological Theory Exclusion: ANT334Y5 =================== ANT350H5 Globalization and the Changing World of Work Prerequisite: ANT204Y5 =================== ANT351H5 Money, Markets, Gifts: Topics in Economic Anthropology Prerequisite: ANT204Y5 =================== ANT352H5 Power, Authority, and Legitimacy: Topics in Political Anthropology Prerequisite: ANT204Y5 =================== ANT358H5 Ethnographic Methods Prerequisite: ANT204Y5 =================== ANT360H5 Anthropology of Religion Exclusion: ANT209Y5 =================== ANT361H5 Anthropology of Sub-Saharan Africa Exclusion: ANT212Y5 =================== ANT362H5 Language in Culture and Society Prerequisite: ANT204Y5 =================== ANT363H5 Magic, Witchcraft and Science Prerequisite: ANT360H5 =================== ANT364H5 Lab in Social Interaction Prerequisite: ANT206H5 =================== ANT365H5 Semiotic Anthropology Prerequisite: ANT204Y5 =================== ANT368H5 World Religions and Ecology Exclusion: RLG311H5 =================== ANT369H5 Religious Violence and Nonviolence Exclusion: RLG317H5 =================== ANT397H5 Independent Study Prerequisite: Permission of Faculty Advisor =================== ANT398Y5 Independent Reading Prerequisite: Permission of Faculty Advisor =================== ANT399Y5 Research Opportunity Program Prerequisite: P.I. =================== ANT401H5 Vocal and Visual Communication Prerequisite: ANT102H5 =================== ANT414H5 People and Plants in Prehistory Prerequisite: ANT200Y5 =================== ANT415H5 Faunal Archaeo-Osteology Exclusion: ANT415Y5 =================== ANT416H5 Advanced Archaeological Analysis Prerequisite: ANT312H5 =================== ANT418H5 Advanced Archaeological Fieldwork Prerequisite: ANT318H5 =================== ANT430H5 Special Problems in Biological Anthropology and Archaeology Prerequisite: P.I =================== ANT430Y5 Special Problems in Biological Anthropology and Archaeology Prerequisite: P.I. =================== ANT431Y5 Special Problems in Sociocultural or Linguistic Anthropology Prerequisite: P.I. =================== ANT431H5 Special Problems in Sociocultural or Linguistic Anthropology Prerequisite: P.I. =================== ANT432H5 Special Seminar in Anthropology Prerequisite: P.I. =================== ANT433H5 Genes, Language, Artifact and Mind Prerequisite: ANT200Y5 =================== ANT434H5 Palaeopathology Prerequisite: ANT334Y5 =================== ANT438H5 The Development of Thought in Biological Anthropology Prerequisite: ANT203Y5 =================== ANT439Y5 Advanced Forensic Anthropology Prerequisite: ANT205H5 =================== ANT441H5 Advanced Bioarchaeology Prerequisite: ANT334H5 =================== ANT457H5 Anthropology and the Environment Prerequisite: ANT102H5 =================== ANT458H5 Anthropology of Crime, Law and Order Exclusion: ANT204Y5 =================== ANT459H5 The Ethnography of Speaking Prerequisite: ANT206Y5 =================== ANT460H5 Theory in Sociocultural Anthropology Prerequisite: ANT204Y5 =================== ANT461H5 Emergent Topics in Socio-Cultural & Linguistic Anthropology Prerequisite: ANT204Y5 =================== ANT498H5 Advanced Independent Study Prerequisite: P.I. =================== ANT499Y5 Advanced Independent Research Prerequisite: P.I.

Answer 2

尝试使用[<int>]

等[position() mod <offset> = <base>]代替

ites = hxs.select("(//p[@class='titlestyle'])[position() mod <offset to next to match> = 2]/text()[1] | (//span[@class='title2'])[position() mod <offset to next to match> = 2]/text() | \
                    (//span[@class='title2'])[position() mod <offset to next to match> = 2]/following-sibling::a[1]/text() | (//span[@class='title2'])[position() mod <offset to next to match> = 3]/text() | \
                    (//span[@class='title2'])[position() mod <offset to next to match> = 3]/following-sibling::a[1]/text()")

偏移是您感兴趣的每个节点之间的距离。 @ class ='titlestyle'和@ class ='title2'可能有所不同。

ites = hxs.select("(//p[@class='titlestyle'])/text()[1]")

编辑：根据要求。

一次一个地执行每个单独的xpath而不限制其位置。这是一个手动事实查找练习，用于确定在xpath中使用的最终值。

返回与以下xpath匹配的所有节点（这是第一个）。

ites

ites将包含您想要的课程和一些您不需要的课程。

您已经确定了第二个是您想要的第一个节点。现在计算您希望此规则匹配的<offset to next to match>中的下一个距离。这就是我们可以称之为{{1}}。

现在对每个剩余的xpath搜索重复上述操作。

将hxs.select（“”）视为过滤器，并且当它遍历xml时，将返回与您的xpath匹配的每一个东西。

以下是http://zvon.org/xxl/XPathTutorial/Output/example22.html

的示例

XPath：按当前节点属性选择当前节点和下一节点的文本

2 个答案: