<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <HTML ><HEAD ><TITLE >DOMXPath->query()</TITLE ><META NAME="GENERATOR" CONTENT="Modular DocBook HTML Stylesheet Version 1.79"><LINK REL="HOME" TITLE="PHP 手册" HREF="index.html"><LINK REL="UP" TITLE="DOM Functions" HREF="ref.dom.html"><LINK REL="PREVIOUS" TITLE="DOMXPath->evaluate()" HREF="function.dom-domxpath-evaluate.html"><LINK REL="NEXT" TITLE="DOMXPath->registerNamespace()" HREF="function.dom-domxpath-registernamespace.html"><META HTTP-EQUIV="Content-type" CONTENT="text/html; charset=UTF-8"></HEAD ><BODY CLASS="refentry" BGCOLOR="#FFFFFF" TEXT="#000000" LINK="#0000FF" VLINK="#840084" ALINK="#0000FF" ><DIV CLASS="NAVHEADER" ><TABLE SUMMARY="Header navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TH COLSPAN="3" ALIGN="center" >PHP 手册</TH ></TR ><TR ><TD WIDTH="10%" ALIGN="left" VALIGN="bottom" ><A HREF="function.dom-domxpath-evaluate.html" ACCESSKEY="P" >上一页</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="function.dom-domxpath-registernamespace.html" ACCESSKEY="N" >下一页</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><H1 ><A NAME="function.dom-domxpath-query" ></A >DOMXPath->query()</H1 ><DIV CLASS="refnamediv" ><A NAME="AEN42671" ></A ><P > (no version information, might be only in CVS)</P >DOMXPath->query() -- Evaluates the given XPath expression </DIV ><DIV CLASS="refsect1" ><A NAME="AEN42674" ></A ><H2 >说明</H2 >class <B CLASS="classname" >DOMXPath</B > { <BR ></BR >DOMNodeList <B CLASS="methodname" >query</B > ( string expression [, DOMNode contextnode] )<BR ></BR >}<P > Executes the given XPath <CODE CLASS="parameter" >expression</CODE >. </P ></DIV ><DIV CLASS="refsect1" ><A NAME="AEN42690" ></A ><H2 >参数</H2 ><P > <P ></P ><DIV CLASS="variablelist" ><DL ><DT ><CODE CLASS="parameter" >expression</CODE ></DT ><DD ><P > The XPath expression to execute. </P ></DD ><DT ><CODE CLASS="parameter" >contextnode</CODE ></DT ><DD ><P > The optional <CODE CLASS="parameter" >contextnode</CODE > can be specified for doing relative XPath queries. By default, the queries are relative to the root element. </P ></DD ></DL ></DIV > </P ></DIV ><DIV CLASS="refsect1" ><A NAME="AEN42705" ></A ><H2 >返回值</H2 ><P > Returns a <B CLASS="classname" >DOMNodeList</B > containing all nodes matching the given XPath <CODE CLASS="parameter" >expression</CODE >. Any expression which do not return nodes will return an empty <B CLASS="classname" >DOMNodeList</B >. </P ></DIV ><DIV CLASS="refsect1" ><A NAME="AEN42711" ></A ><H2 >范例</H2 ><P > <TABLE WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" CLASS="EXAMPLE" ><TR ><TD ><DIV CLASS="example" ><A NAME="AEN42714" ></A ><P ><B >例 1. Getting all the english books</B ></P ><TABLE BORDER="0" BGCOLOR="#E0E0E0" CELLPADDING="5" ><TR ><TD ><code><font color="#000000"> <font color="#0000BB"><?php<br /><br />$doc </font><font color="#007700">= new </font><font color="#0000BB">DOMDocument</font><font color="#007700">;<br /><br /></font><font color="#FF8000">// We don't want to bother with white spaces<br /></font><font color="#0000BB">$doc</font><font color="#007700">-></font><font color="#0000BB">preserveWhiteSpace </font><font color="#007700">= </font><font color="#0000BB">false</font><font color="#007700">;<br /><br /></font><font color="#0000BB">$doc</font><font color="#007700">-></font><font color="#0000BB">Load</font><font color="#007700">(</font><font color="#DD0000">'book.xml'</font><font color="#007700">);<br /><br /></font><font color="#0000BB">$xpath </font><font color="#007700">= new </font><font color="#0000BB">DOMXPath</font><font color="#007700">(</font><font color="#0000BB">$doc</font><font color="#007700">);<br /><br /></font><font color="#FF8000">// We starts from the root element<br /></font><font color="#0000BB">$query </font><font color="#007700">= </font><font color="#DD0000">'//book/chapter/para/informaltable/tgroup/tbody/row/entry[. = "en"]'</font><font color="#007700">;<br /><br /></font><font color="#0000BB">$entries </font><font color="#007700">= </font><font color="#0000BB">$xpath</font><font color="#007700">-></font><font color="#0000BB">query</font><font color="#007700">(</font><font color="#0000BB">$query</font><font color="#007700">);<br /><br />foreach (</font><font color="#0000BB">$entries </font><font color="#007700">as </font><font color="#0000BB">$entry</font><font color="#007700">) {<br /> echo </font><font color="#DD0000">"Found </font><font color="#007700">{</font><font color="#DD0000">$entry</font><font color="#007700">-></font><font color="#DD0000">previousSibling</font><font color="#007700">-></font><font color="#DD0000">previousSibling</font><font color="#007700">-></font><font color="#DD0000">nodeValue</font><font color="#007700">}</font><font color="#DD0000">," </font><font color="#007700">.<br /> </font><font color="#DD0000">" by </font><font color="#007700">{</font><font color="#DD0000">$entry</font><font color="#007700">-></font><font color="#DD0000">previousSibling</font><font color="#007700">-></font><font color="#DD0000">nodeValue</font><font color="#007700">}\n</font><font color="#DD0000">"</font><font color="#007700">;<br />}<br /></font><font color="#0000BB">?></font> </font> </code></TD ></TR ></TABLE ><P >上例将输出:</P ><TABLE BORDER="0" BGCOLOR="#E0E0E0" CELLPADDING="5" ><TR ><TD ><PRE CLASS="screen" >Found The Grapes of Wrath, by John Steinbeck Found The Pearl, by John Steinbeck</PRE ></TD ></TR ></TABLE ><P > We can also use the <CODE CLASS="parameter" >contextnode</CODE > parameter to shorten our expression: </P ><TABLE BORDER="0" BGCOLOR="#E0E0E0" CELLPADDING="5" ><TR ><TD ><code><font color="#000000"> <font color="#0000BB"><?php<br /><br />$doc </font><font color="#007700">= new </font><font color="#0000BB">DOMDocument</font><font color="#007700">;<br /></font><font color="#0000BB">$doc</font><font color="#007700">-></font><font color="#0000BB">preserveWhiteSpace </font><font color="#007700">= </font><font color="#0000BB">false</font><font color="#007700">;<br /><br /></font><font color="#0000BB">$doc</font><font color="#007700">-></font><font color="#0000BB">load</font><font color="#007700">(</font><font color="#DD0000">'book.xml'</font><font color="#007700">);<br /><br /></font><font color="#0000BB">$xpath </font><font color="#007700">= new </font><font color="#0000BB">DOMXPath</font><font color="#007700">(</font><font color="#0000BB">$doc</font><font color="#007700">);<br /><br /></font><font color="#0000BB">$tbody </font><font color="#007700">= </font><font color="#0000BB">$doc</font><font color="#007700">-></font><font color="#0000BB">getElementsByTagName</font><font color="#007700">(</font><font color="#DD0000">'tbody'</font><font color="#007700">)-></font><font color="#0000BB">item</font><font color="#007700">(</font><font color="#0000BB">0</font><font color="#007700">);<br /><br /></font><font color="#FF8000">// our query is relative to the tbody node<br /></font><font color="#0000BB">$query </font><font color="#007700">= </font><font color="#DD0000">'row/entry[. = "en"]'</font><font color="#007700">;<br /><br /></font><font color="#0000BB">$entries </font><font color="#007700">= </font><font color="#0000BB">$xpath</font><font color="#007700">-></font><font color="#0000BB">query</font><font color="#007700">(</font><font color="#0000BB">$query</font><font color="#007700">, </font><font color="#0000BB">$tbody</font><font color="#007700">);<br /><br />foreach (</font><font color="#0000BB">$entries </font><font color="#007700">as </font><font color="#0000BB">$entry</font><font color="#007700">) {<br /> echo </font><font color="#DD0000">"Found </font><font color="#007700">{</font><font color="#DD0000">$entry</font><font color="#007700">-></font><font color="#DD0000">previousSibling</font><font color="#007700">-></font><font color="#DD0000">previousSibling</font><font color="#007700">-></font><font color="#DD0000">nodeValue</font><font color="#007700">}</font><font color="#DD0000">," </font><font color="#007700">.<br /> </font><font color="#DD0000">" by </font><font color="#007700">{</font><font color="#DD0000">$entry</font><font color="#007700">-></font><font color="#DD0000">previousSibling</font><font color="#007700">-></font><font color="#DD0000">nodeValue</font><font color="#007700">}\n</font><font color="#DD0000">"</font><font color="#007700">;<br />}<br /></font><font color="#0000BB">?></font> </font> </code></TD ></TR ></TABLE ></DIV ></TD ></TR ></TABLE > </P ></DIV ><DIV CLASS="refsect1" ><A NAME="AEN42722" ></A ><H2 >参见</H2 ><P > <P ></P ><TABLE BORDER="0" ><TBODY ><TR ><TD ><A HREF="function.dom-domxpath-evaluate.html" >DOMXPath->evaluate()</A ></TD ></TR ></TBODY ></TABLE ><P ></P > </P ></DIV ><DIV CLASS="NAVFOOTER" ><HR ALIGN="LEFT" WIDTH="100%"><TABLE SUMMARY="Footer navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" ><A HREF="function.dom-domxpath-evaluate.html" ACCESSKEY="P" >上一页</A ></TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="index.html" ACCESSKEY="H" >起始页</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" ><A HREF="function.dom-domxpath-registernamespace.html" ACCESSKEY="N" >下一页</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >DOMXPath->evaluate()</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="ref.dom.html" ACCESSKEY="U" >上一级</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >DOMXPath->registerNamespace()</TD ></TR ></TABLE ></DIV ></BODY ></HTML >