<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <HTML ><HEAD ><TITLE >abs</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="Math 数学函数" HREF="ref.math.html"><LINK REL="PREVIOUS" TITLE="Math 数学函数" HREF="ref.math.html"><LINK REL="NEXT" TITLE="acos" HREF="function.acos.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="ref.math.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.acos.html" ACCESSKEY="N" >下一页</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><H1 ><A NAME="function.abs" ></A >abs</H1 ><DIV CLASS="refnamediv" ><A NAME="AEN107997" ></A ><P > (PHP 3, PHP 4, PHP 5)</P >abs -- 绝对值</DIV ><DIV CLASS="refsect1" ><A NAME="AEN108000" ></A ><H2 >说明</H2 >number <B CLASS="methodname" >abs</B > ( mixed number )<BR ></BR ><P > 返回参数 <CODE CLASS="parameter" >number</CODE > 的绝对值。如果参数 <CODE CLASS="parameter" >number</CODE > 是 <A HREF="language.types.float.html" ><B CLASS="type" >float</B ></A >,则返回的类型也是 <A HREF="language.types.float.html" ><B CLASS="type" >float</B ></A >,否则返回 <A HREF="language.types.integer.html" ><B CLASS="type" >integer</B ></A >(因为 <A HREF="language.types.float.html" ><B CLASS="type" >float</B ></A > 通常比 <A HREF="language.types.integer.html" ><B CLASS="type" >integer</B ></A > 有更大的取值范围)。 </P ><TABLE WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" CLASS="EXAMPLE" ><TR ><TD ><DIV CLASS="example" ><A NAME="AEN108016" ></A ><P ><B >例 1. <B CLASS="function" >abs()</B > </B ></P ><TABLE BORDER="0" BGCOLOR="#E0E0E0" CELLPADDING="5" ><TR ><TD ><code><font color="#000000"> <font color="#0000BB"><?php<br />$abs </font><font color="#007700">= </font><font color="#0000BB">abs</font><font color="#007700">(-</font><font color="#0000BB">4.2</font><font color="#007700">); </font><font color="#FF8000">// $abs = 4.2; (double/float)<br /></font><font color="#0000BB">$abs2 </font><font color="#007700">= </font><font color="#0000BB">abs</font><font color="#007700">(</font><font color="#0000BB">5</font><font color="#007700">); </font><font color="#FF8000">// $abs2 = 5; (integer)<br /></font><font color="#0000BB">$abs3 </font><font color="#007700">= </font><font color="#0000BB">abs</font><font color="#007700">(-</font><font color="#0000BB">5</font><font color="#007700">); </font><font color="#FF8000">// $abs3 = 5; (integer)<br /></font><font color="#0000BB">?></font> </font> </code></TD ></TR ></TABLE ></DIV ></TD ></TR ></TABLE ></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="ref.math.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.acos.html" ACCESSKEY="N" >下一页</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >Math 数学函数</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="ref.math.html" ACCESSKEY="U" >上一级</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >acos</TD ></TR ></TABLE ></DIV ></BODY ></HTML >