<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <HTML ><HEAD ><TITLE >preg_replace_callback</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="Perl 兼容正则表达式函数" HREF="ref.pcre.html"><LINK REL="PREVIOUS" TITLE="preg_quote" HREF="function.preg-quote.html"><LINK REL="NEXT" TITLE="preg_replace" HREF="function.preg-replace.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.preg-quote.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.preg-replace.html" ACCESSKEY="N" >下一页</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><H1 ><A NAME="function.preg-replace-callback" ></A >preg_replace_callback</H1 ><DIV CLASS="refnamediv" ><A NAME="AEN171830" ></A ><P > (PHP 4 >= 4.0.5, PHP 5)</P >preg_replace_callback -- 用回调函数执行正则表达式的搜索和替换</DIV ><DIV CLASS="refsect1" ><A NAME="AEN171833" ></A ><H2 >说明</H2 >mixed <B CLASS="methodname" >preg_replace_callback</B > ( mixed pattern, callback callback, mixed subject [, int limit] )<BR ></BR ><P > 本函数的行为几乎和 <A HREF="function.preg-replace.html" ><B CLASS="function" >preg_replace()</B ></A > 一样,除了不是提供一个 <CODE CLASS="parameter" >replacement</CODE > 参数,而是指定一个 <CODE CLASS="parameter" >callback</CODE > 函数。该函数将以目标字符串中的匹配数组作为输入参数,并返回用于替换的字符串。 </P ><TABLE WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" CLASS="EXAMPLE" ><TR ><TD ><DIV CLASS="example" ><A NAME="AEN171854" ></A ><P ><B >例 1. <B CLASS="function" >preg_replace_callback()</B > 例子</B ></P ><TABLE BORDER="0" BGCOLOR="#E0E0E0" CELLPADDING="5" ><TR ><TD ><code><font color="#000000"> <font color="#0000BB"><?php<br /> </font><font color="#FF8000">// 此文本是用于 2002 年的,<br /> // 现在想使其能用于 2003 年<br /> </font><font color="#0000BB">$text </font><font color="#007700">= </font><font color="#DD0000">"April fools day is 04/01/2002\n"</font><font color="#007700">;<br /> </font><font color="#0000BB">$text</font><font color="#007700">.= </font><font color="#DD0000">"Last christmas was 12/24/2001\n"</font><font color="#007700">;<br /><br /> </font><font color="#FF8000">// 回调函数<br /> </font><font color="#007700">function </font><font color="#0000BB">next_year</font><font color="#007700">(</font><font color="#0000BB">$matches</font><font color="#007700">) {<br /> </font><font color="#FF8000">// 通常:$matches[0] 是完整的匹配项<br /> // $matches[1] 是第一个括号中的子模式的匹配项<br /> // 以此类推<br /> </font><font color="#007700">return </font><font color="#0000BB">$matches</font><font color="#007700">[</font><font color="#0000BB">1</font><font color="#007700">].(</font><font color="#0000BB">$matches</font><font color="#007700">[</font><font color="#0000BB">2</font><font color="#007700">]+</font><font color="#0000BB">1</font><font color="#007700">);<br /> }<br /><br /> echo </font><font color="#0000BB">preg_replace_callback</font><font color="#007700">(<br /> </font><font color="#DD0000">"|(\d{2}/\d{2}/)(\d{4})|"</font><font color="#007700">,<br /> </font><font color="#DD0000">"next_year"</font><font color="#007700">,<br /> </font><font color="#0000BB">$text</font><font color="#007700">);<br /><br /> </font><font color="#FF8000">// 结果为:<br /> // April fools day is 04/01/2003<br /> // Last christmas was 12/24/2002<br /></font><font color="#0000BB">?></font> </font> </code></TD ></TR ></TABLE ></DIV ></TD ></TR ></TABLE ><P > You'll often need the <CODE CLASS="parameter" >callback</CODE > function for a <B CLASS="function" >preg_replace_callback()</B > in just one place. In this case you can use <A HREF="function.create-function.html" ><B CLASS="function" >create_function()</B ></A > to declare an anonymous function as callback within the call to <B CLASS="function" >preg_replace_callback()</B >. By doing it this way you have all information for the call in one place and do not clutter the function namespace with a callback functions name not used anywhere else. </P ><TABLE WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" CLASS="EXAMPLE" ><TR ><TD ><DIV CLASS="example" ><A NAME="AEN171863" ></A ><P ><B >例 2. <B CLASS="function" >preg_replace_callback()</B > 和 <A HREF="function.create-function.html" ><B CLASS="function" >create_function()</B ></A ></B ></P ><TABLE BORDER="0" BGCOLOR="#E0E0E0" CELLPADDING="5" ><TR ><TD ><code><font color="#000000"> <font color="#0000BB"><?php<br /> </font><font color="#FF8000">/* 一个 UNIX 风格的命令行过滤器,将每个段落开头的<br /> * 大写字母转换成小写字母 */<br /><br /> </font><font color="#0000BB">$fp </font><font color="#007700">= </font><font color="#0000BB">fopen</font><font color="#007700">(</font><font color="#DD0000">"php://stdin"</font><font color="#007700">, </font><font color="#DD0000">"r"</font><font color="#007700">) or die(</font><font color="#DD0000">"can't read stdin"</font><font color="#007700">);<br /> while (!</font><font color="#0000BB">feof</font><font color="#007700">(</font><font color="#0000BB">$fp</font><font color="#007700">)) {<br /> </font><font color="#0000BB">$line </font><font color="#007700">= </font><font color="#0000BB">fgets</font><font color="#007700">(</font><font color="#0000BB">$fp</font><font color="#007700">);<br /> </font><font color="#0000BB">$line </font><font color="#007700">= </font><font color="#0000BB">preg_replace_callback</font><font color="#007700">(<br /> </font><font color="#DD0000">'|<p>\s*\w|'</font><font color="#007700">,<br /> </font><font color="#0000BB">create_function</font><font color="#007700">(<br /> </font><font color="#FF8000">// 这里使用单引号很关键,<br /> // 否则就把所有的 $ 换成 \$<br /> </font><font color="#DD0000">'$matches'</font><font color="#007700">,<br /> </font><font color="#DD0000">'return strtolower($matches[0]);'<br /> </font><font color="#007700">),<br /> </font><font color="#0000BB">$line<br /> </font><font color="#007700">);<br /> echo </font><font color="#0000BB">$line</font><font color="#007700">;<br /> }<br /> </font><font color="#0000BB">fclose</font><font color="#007700">(</font><font color="#0000BB">$fp</font><font color="#007700">);<br /></font><font color="#0000BB">?></font> </font> </code></TD ></TR ></TABLE ></DIV ></TD ></TR ></TABLE ><P > 参见 <A HREF="function.preg-replace.html" ><B CLASS="function" >preg_replace()</B ></A > 和 <A HREF="function.create-function.html" ><B CLASS="function" >create_function()</B ></A >。 </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.preg-quote.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.preg-replace.html" ACCESSKEY="N" >下一页</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >preg_quote</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="ref.pcre.html" ACCESSKEY="U" >上一级</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >preg_replace</TD ></TR ></TABLE ></DIV ></BODY ></HTML >