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正則入門連載?。ǐI(xiàn)給不及格的程序員們）第3/4頁(yè)

更新時(shí)間：2007年02月05日 00:00:00 作者：

優(yōu)先級(jí)順序
說(shuō)明如何計(jì)算正則表達(dá)式以及正則表達(dá)式的序列和語(yǔ)法對(duì)結(jié)果有何影響。

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN"> <HTML xmlns:MSHelp="http://msdn.microsoft.com/mshelp" DIR="LTR"> <style type="text/css"> /* VERSION 9345 Designed for IE5.x. Optimal in IE 6.x CSS for use with Developer Tools Documentation Localizable definitions: font families font sizes */ /* --------------------------------------------------                   MAIN TOPIC STYLES -------------------------------------------------- */ div.saveHistory     {     behavior:url(#default#savehistory);     text-decoration: underline     } body /* This body tag requires the use of one of the sets of banner and/or text div ids */     {     margin: 0px 0px 0px 0px;     padding: 0px 0px 0px 0px;     background: #ffffff;      color: #000000;     font-family: 瀹嬩綋, Verdana, Arial, Helvetica, sans-serif;     font-size: 75%;     width: 100%;     } div#scrollyes /* Allows topic to scroll with correct margins. Cannot be used with running head banner */     {     /* Must immediately follow <body>. */     padding: 2px 15px 2px 22px;     width: 100%;     } div#nsbanner /* Creates Nonscrolling banner region */     {     position: relative;     left: 0px;     padding: 0px 0px 0px 0px;     border-bottom: 1px solid #999999;     } div#nstext /* Creates the scrolling text area for Nonscrolling region topic */     {     padding: 5px 10px 0px 22px;      } div#scrbanner /* Creates the running head bar in a full-scroll topic */     {     /* Allows topic to scroll. */     margin: 0px 0px 0px 0px;     padding: 0px 0px 0px 0px;     border-bottom: 1px solid #999999;     } div#scrtext /* Creates the text area in a full-scroll topic */     {   /* Allows topic to scroll. */ /*    width: 100%; /* Forces tables to have correct right margin */*/     padding: 0px 10px 0px 22px;      } div#bannerrow1 /* provides full-width color to top row in running head (requires script) */     {     background-color: #99ccff;     } div#titlerow /* provides non-scroll topic title area (requires script) */     {     width: 100%; /* Forces tables to have correct right margin */     padding: 0px 10px 0px 22px;      background-color: #99ccff;             } /* --------------------------------------------------                     HEADING STYLES -------------------------------------------------- */ h1, h2, h3, h4     {     font-family: 瀹嬩綋, Verdana, Arial, Helvetica, sans-serif;     margin-bottom: .4em;      margin-top: 1em;     font-weight: bold;     } h1     {     font-size: 120%;     margin-top: 0em;     } div#scrollyes h1 /* Changes font size for full-scrolling topic */     {     font-size: 150%;     } h2     {     font-size: 120%;     } h3     {     font-size: 115%;     } h4     {     font-size: 100%;     } .dtH1, .dtH2, .dtH3, .dtH4     {     margin-left: -18px;     } div#titlerow h1     {     margin-bottom: .2em     } /* --------------------------------------------------                      TEXT STYLES -------------------------------------------------- */ p     {     margin: .5em 0em .5em 0em;     } blockquote.dtBlock     {     margin: .5em 1.5em .5em 1.5em;     } div#dtHoverText     {     color: #000066;     } .normal     {     margin: .5em 0em .5em 0em;     } .fineprint     {     font-size: 110%; /* 90% of 70% */     } .indent     {     margin: .5em 1.5em .5em 1.5em;     } .topicstatus /* Topic Status Boilerplate class */     {     display: block;     color: red;     } /* --------------------------------------------------                      LABEL STYLES -------------------------------------------------- */ p.label     {     margin-top: 1em;     } p.labelproc     {     margin-top: 1em;     color: #000066;     } /* --------------------------------------------------                     GRAPHIC STYLES -------------------------------------------------- */ img     {     border: none;      } /* --------------------------------------------------                      LIST STYLES -------------------------------------------------- */ ol, ul     {     margin: .5em 0em 0em 2em;      } li     {     margin-bottom: .5em;     } ul p, ol p, dl p     {     margin-left: 0em;     } ul p.label, ol p.label     {     margin-top: .5em;     } /* --------------------------------------------------                DEFINITION LIST STYLES -------------------------------------------------- */ dl     {     margin-top: 0em;      padding-left: 1px; /* Prevents italic-letter descenders from being cut off */     } dd     {     margin-bottom: 0em;       margin-left: 1.5em;      } dt     {     margin-top: .5em;      } /* --------------------------------------------------            CODE, SYNTAX, and REFTIP STYLES -------------------------------------------------- */ pre     {     margin-top: .5em;     margin-bottom: .5em;      } pre, code, .code     {     font: 100% 瀹嬩綋, Courier New, Monospace, Courier;/* This is 100% of 70% */     color: #000066;     } pre b, code b     {     letter-spacing: .1em; /* opens kerning on bold in Syntax/Code */     } pre.syntax     {     font: 100% Courier New, 瀹嬩綋, Monospace, Courier;/* This is 100% of 70% */     background: #cccccc;     padding: 4px 8px;     cursor: text;     margin-top: 1em;     margin-bottom: 1em;      color: #000000;     border-width: 1px;     border-style: solid;     border-color: #999999;     } /* --------------------------------------------------                       LINK STYLES -------------------------------------------------- */ a:link     {     color: #0000ff;     } a:visited     {     color: #0000ff;     } a:hover     {     color: #3366ff;     } /* --------------------------- MSHelp\:link - Help HxLinks --------------------------- */ MSHelp\:link     {     text-decoration: underline;      color: #0000ff;      hoverColor: #3366ff;     filterString: ;     }     A.HxLinkTable /* MSHelp\:link - Table disambiguation elements */     {     } /* --------------------------- MSHelp\:ktable - Help links --------------------------- */ MSHelp\:ktable     {     disambiguator: span;     separator: &nbsp|&#32;     prefix: |&#32;     postfix: &nbsp;     filterString: ;     } div.HxLinkTable     {     width: auto; /* Forces tables to have correct right margins and top spacing */     margin-top: -.4em;     visibility: visible;     } ol div.HxLinkTable, ul div.HxLinkTable     {     margin-top: 0em; /* Forces tables to have correct right margins and top spacing */     } table.HxLinkTable /* Keep in sync with general table settings below */     {     width: auto;     margin-top: 1.5em;     margin-bottom: .3em;     margin-left: -1em;     border-width: 1px 1px 0px 0px;     border-style: solid;     border-color: #999999;     background-color: #999999;      font-size: 100%; /* Text in Table is same size as text outside table */     behavior:url(hxlinktable.htc); /* Attach the behavior to link elements. */     } table.HxLinkTable th, table.HxLinkTable td /* Keep in sync with general table settings below */     {      border-style: solid; /* Creates the cell border and color */     border-width: 0px 0px 1px 1px;     border-style: solid;     border-color: #999999;     padding: 4px 6px;     text-align: left;     } table.HxLinkTable th /* Keep in sync with general table settings below */     {      background: #cccccc; /* Creates the shaded table header row */     vertical-align: bottom;     } table.HxLinkTable td /* Keep in sync with general table settings below */     {     background: #ffffff;     vertical-align: top;     } /* --------------------------------------------------                     TABLE STYLES -------------------------------------------------- */ div.tablediv     {     width: 100%; /* Forces tables to have correct right margins and top spacing */     margin-top: -.4em;     } ol div.tablediv, ul div.tablediv, ol div.HxLinkTable, ul div.HxLinkTable     {     margin-top: 0em; /* Forces tables to have correct right margins and top spacing */     } table.dtTABLE     {     width: 100%; /* Forces tables to have correct right margin */     margin-top: .6em;     margin-bottom: .3em;     border-width: 1px 1px 0px 0px;     border-style: solid;     border-color: #999999;     background-color: #999999;      font-size: 100%; /* Text in Table is same size as text outside table */     } table.dtTABLE th, table.dtTABLE td     {      border-style: solid; /* Creates the cell border and color */     border-width: 0px 0px 1px 1px;     border-style: solid;     border-color: #999999;     padding: 4px 6px;     text-align: left;     } table.dtTABLE th         {      background: #cccccc; /* Creates the shaded table header row */     vertical-align: bottom;     } table.dtTABLE td         {     background: #ffffff;     vertical-align: top;     } /* -------------------------------------------------- ISSUE REPORTING AND MISC LINKS TOPIC FOOTER -------------------------------------------------- */ div.footer     {          } div.footer hr     {     color: #999999;     height: 1px;     } /* --------------------------------------------------              STYLES FOR RUNNING HEADS -------------------------------------------------- */ table.bannerparthead, table.bannertitle /* General values for the Running Head tables */     {     position: relative;     left: 0px;     top: 0px;     padding: 0px 0px 0px 0px;     margin: 0px 0px 0px 0px;     width: 100%;     height: 21px;      border-collapse: collapse;     border-style: solid;     border-width: 0px;     background-color: #99ccff;      font-size: 100%;     } table.bannerparthead td /* General Values for cells in the top row of running head */     {     margin: 0px 0px 0px 0px;     padding: 2px 0px 0px 4px;     vertical-align: middle;     /*border-width: 0px 0px 1px 0px; */     border-width: 0px     border-style: solid;     border-color: #999999;     background: transparent;      /* font-style: normal; */     font-weight: normal;     } table.bannerparthead td.product /* Values for top right cell in running head */     {                       /* Allows for a second text block in the running head */     text-align: right;     padding: 2px 5px 0px 5px;     } table.bannertitle td /* General Values for cells in the bottom row of running head */     {     margin: 0px 0px 0px 0px;     padding: 0px 0px 0px 3px;     vertical-align: middle;     border-width: 0px 0px 1px 0px;     border-style: solid;     border-color: #999999;     background: transparent;     font-weight: bold;     } td.button1 /* Values for button cells */     {     width: 14px;     cursor: hand;     } /* =================================================             STYLES REQUIRED BY THE SCRIPT */ /* --------------------------------------------------                   SAMPLE VIEWER -------------------------------------------------- */ div#smpMgrCell     {     display:none;     } table.SampMgr     {     margin: 0px 0px 0px -22px;     } table.SampMgr td     {     padding-left: 22px;     } /* -------------------------------------------------- RUNNING HEAD BAR POPUP STYLES: See Also, Requirements, MultiLang Filtering -------------------------------------------------- */ div.sapop, div.langMenu /* See Also & Requirements popups */     {     position: absolute;     left: 0px;     z-index: 1;     width: 50%;     padding: 0px 8px 5px 26px;     visibility: hidden;     border: 1px solid #999999; /* Same as all other border colors */     background: #ffffcc;     } div.langMenu /* MultiLang Filter popup */     {     padding: 10px 10px 10px 10px;     } div.langMenu ul     {     list-style-type: none;     padding-left: 5px;     margin-left: 0px;     } .lang, .ilang /* controls the multilang tag styles */     {     color: #333333;     font-family: Verdana, Arial, 瀹嬩綋, Helvetica, sans-serif;     font-size: 80%;     font-weight: normal;     font-style: normal;     } h1 .lang, h1 .ilang      {     font-size: 80%;     } div.filtered     {     margin-top: .6em;     margin-bottom: .6em;     margin-left: -7px;     padding: 0px 0px 0px 6px;     border-left: 1px solid #999999;     background: #ffffff;     } div.filtered h1, div.filtered h2, div.filtered h3, div.filtered h4     {     margin-left: -22px;     } div.filtered span.lang     {     position: relative;     left: 0px;     } /* --------------------------------------------------               PARAMETER POPUP STYLES -------------------------------------------------- */ div.reftip /* Defines the RefTip popup in Syntax */     {     position: absolute;     z-index: 1;     visibility: hidden;     border: 1px solid #999999;     background: #ffffcc; /*    padding: 0px 0px 0px 0px; */         } div.reftip dl /* Sets margin around the text within the popup */     {     margin: 3px 8px 8px 8px;     } a.synParam /* parameter popup links */     {     color: #0000ff; /* Must match the a:link style color */     text-decoration: underline;     } a.synParam:visited /* ensures parameter popup links are always the unvisited color */     {     color: #0000ff; /* Must match the a:link style color */     text-decoration: underline;     } a.synParam:hover /* parameter popup links */     {     color: #3366ff; /* Must match the a:hover style color */     text-decoration: underline;     font-style: italic;     } /* --------------------------------------------------               EXPAND-COLLAPSE STYLES -------------------------------------------------- */ div.expandBody     {     margin: .5em 0em 0em 1.4em;     display:none;     } a.expandLink1     {     font-size: 115%;      } a#ExPand     {     color: #3366ff;      font-weight: bold;      text-decoration: none;      } a#ExPandAll     {     color: #3366ff;      font-weight: bold;      text-decoration: none;      } /* --------------------------------------------------               GLOSSARY POPUP STYLES            Not used by Visual Studio .NET  -------------------------------------------------- */ /* COMMENT OUT GLOSSARY SECTION /*div#popUpWindow     { Controlled by the script in the variable L_PopUpBoxStyle_Style     }*/ a.glosslink:link     {     color: #000000;     } a.glosslink:visited     {     color: #000000;      } a.glosslink:hover     {     color: #000000;     font-style: italic;     } div#popUpWindow h5 /* Controls the style of the Term in Glossary Popups */     {     margin: 5px 5px 5px 5px;     color: #000000;     } div#popUpWindow p /* Controls the style of the Text in Glossary Popups */     {     margin: 5px 5px 5px 5px;     color: #000000;     } p.GLOSSARY_TEXT     {     } div#popUpWindow a /* Controls the style of the Links in Glossary Popups */     {     } */ /* END COMMENT OUT OF GLOSSARY SECTION */ /* END STYLES REQUIRED BY THE SCRIPT  ================================================== */ </style> <HEAD> <META HTTP-EQUIV="Content-Type" Content="text/html; charset=gb2312"> <TITLE>優(yōu)先級(jí)順序</TITLE> <xml> <MSHelp:TOCTitle Title="優(yōu)先級(jí)順序"/> <MSHelp:RLTitle Title="優(yōu)先級(jí)順序 (JScript .NET)"/> <MSHelp:Keyword Index="A" Term="jsreconOrderOfPrecedence"/> <MSHelp:Keyword Index="A" Term="jsreconOrderOfPrecedence"/> <MSHelp:Keyword Index="K" Term="正則表達(dá)式, 優(yōu)先級(jí)順序"/> <MSHelp:Keyword Index="K" Term="優(yōu)先級(jí), 正則表達(dá)式"/> <MSHelp:Keyword Index="K" Term="正則表達(dá)式的優(yōu)先級(jí)順序"/> <MSHelp:Attr Name="DevLang" Value="JScript"/> <MSHelp:Attr Name="DevLangVers" Value="kbJScript"/> <MSHelp:Attr Name="DocSet" Value="JScript"/> <MSHelp:Attr Name="DocSet" Value="Visual Studio"/> <MSHelp:Attr Name="Product" Value="VS"/> <MSHelp:Attr Name="ProductVers" Value="kbVS700"/> <MSHelp:Attr Name="Technology" Value="ManagedCode"/> <MSHelp:Attr Name="TechnologyVers" Value="kbManagedCode"/> <MSHelp:Attr Name="TopicType" Value="kbArticle"/> <MSHelp:Attr Name="TargetOS" Value="Windows"/> <MSHelp:Attr Name="Locale" Value="kbChineseSimp"/> </xml> <META name="rtfFileName" content="js7reregexp.rtf"> <META NAME="save" CONTENT="history">   <META NAME="msdnID" CONTENT="_731803"> </HEAD> <body topmargin=0 id="bodyID" class = "dtBODY"> <div   class="vvxyksv9kd"   id="nsbanner"> <div   class="vvxyksv9kd"   id="bannerrow1"> <TABLE CLASS="bannerparthead" CELLSPACING=0> <TR ID="hdr"> <TD CLASS="runninghead" nowrap>JScript .NET</TD> <TD CLASS="product" nowrap>&nbsp;</TD> </TR> </TABLE> </div> <div   class="vvxyksv9kd"   id="TitleRow"> <H1 class="dtH1"><A NAME="jsreconorderofprecedence"></A>優(yōu)先級(jí)順序</H1> </div></div>  <div   class="vvxyksv9kd"   id="nstext" valign="bottom"> <P>正則表達(dá)式從左到右進(jìn)行計(jì)算，并遵循優(yōu)先級(jí)順序，這與算術(shù)表達(dá)式非常類似。</P> <P>下表從最高到最低說(shuō)明了各種正則表達(dá)式運(yùn)算符的優(yōu)先級(jí)順序：</P> <div   id="vvxyksv9kd"   class="tablediv"><table cellspacing="0" class="dtTABLE"> <TR VALIGN="top"> <TH width=40%>運(yùn)算符</TH> <TH width=60%>說(shuō)明</TH> </TR> <TR VALIGN="top"> <TD width=40%>\</TD> <TD width=60%>轉(zhuǎn)義符</TD> </TR> <TR VALIGN="top"> <TD width=40%>(), (?:), (?=), []</TD> <TD width=60%>括號(hào)和中括號(hào)</TD> </TR> <TR VALIGN="top"> <TD width=40%>*, +, ?, {n}, {n,}, {n,m}</TD> <TD width=60%>限定符</TD> </TR> <TR VALIGN="top"> <TD width=40%>^, $, \<I>anymetacharacter, anycharacter</I></TD> <TD width=60%>定位點(diǎn)和序列</TD> </TR> <TR VALIGN="top"> <TD width=40%>|</TD> <TD width=60%>替換</TD> </TR> </table></div> <P>字符比替換運(yùn)算符具有更高的優(yōu)先級(jí)，這樣使得"m|food"匹配"m"或者"food"。若要匹配"mood"或"food"，請(qǐng)使用括號(hào)創(chuàng)建子表達(dá)式，從而產(chǎn)生"(m|f)ood"。</P> <H4 class="dtH4">請(qǐng)參見</H4> <P><A HREF="jsreconintroductiontoregularexpressions.htm">正則表達(dá)式介紹</A></P>  <div   id="vvxyksv9kd"   class="footer">  <HR> <p><A HREF="JavaScript:sendfeedback('CHS _731803', 'VSDOCS@MICROSOFT.COM')">將文檔反饋發(fā)送給 Microsoft</A></p> <p><MSHelp:link keywords="vxmscCopyright" TABINDEX="0">&copy; 2002 Microsoft Corporation。保留所有權(quán)利。</MSHelp:link></p></div>  </div>   </BODY> </HTML>

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普通字符
區(qū)分普通字符與元字符，并說(shuō)明如何將多個(gè)單字符正則表達(dá)式組合在一起，以創(chuàng)建更大的表達(dá)式。

普通字符包括沒有顯式指定為元字符的所有可打印和不可打印字符。這包括所有大寫和小寫字母、所有數(shù)字、所有標(biāo)點(diǎn)符號(hào)和一些其他符號(hào)。

正則表達(dá)式的最簡(jiǎn)單形式是在搜索字符串中匹配其本身的單個(gè)普通字符。例如，單字符模式，如 A，不論出現(xiàn)在搜索字符串中的何處，它總是匹配字母 A。下面是一些單字符正則表達(dá)式模式的示例：

/a/
/7/
/M/
可以將許多單字符組合起來(lái)以形成大的表達(dá)式。例如，以下正則表達(dá)式組合了單字符表達(dá)式：a、7 和 M。

/a7M/
請(qǐng)注意，沒有串聯(lián)運(yùn)算符。只須在一個(gè)字符后面鍵入另一個(gè)字符。
特殊字符
說(shuō)明轉(zhuǎn)義符的概念以及如何創(chuàng)建與元字符匹配的正則表達(dá)式。

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN"> <HTML xmlns:MSHelp="http://msdn.microsoft.com/mshelp" DIR="LTR"> <style type="text/css"> /* VERSION 9345 Designed for IE5.x. Optimal in IE 6.x CSS for use with Developer Tools Documentation Localizable definitions: font families font sizes */ /* --------------------------------------------------                   MAIN TOPIC STYLES -------------------------------------------------- */ div.saveHistory     {     behavior:url(#default#savehistory);     text-decoration: underline     } body /* This body tag requires the use of one of the sets of banner and/or text div ids */     {     margin: 0px 0px 0px 0px;     padding: 0px 0px 0px 0px;     background: #ffffff;      color: #000000;     font-family: 瀹嬩綋, Verdana, Arial, Helvetica, sans-serif;     font-size: 75%;     width: 100%;     } div#scrollyes /* Allows topic to scroll with correct margins. Cannot be used with running head banner */     {     /* Must immediately follow <body>. */     padding: 2px 15px 2px 22px;     width: 100%;     } div#nsbanner /* Creates Nonscrolling banner region */     {     position: relative;     left: 0px;     padding: 0px 0px 0px 0px;     border-bottom: 1px solid #999999;     } div#nstext /* Creates the scrolling text area for Nonscrolling region topic */     {     padding: 5px 10px 0px 22px;      } div#scrbanner /* Creates the running head bar in a full-scroll topic */     {     /* Allows topic to scroll. */     margin: 0px 0px 0px 0px;     padding: 0px 0px 0px 0px;     border-bottom: 1px solid #999999;     } div#scrtext /* Creates the text area in a full-scroll topic */     {   /* Allows topic to scroll. */ /*    width: 100%; /* Forces tables to have correct right margin */*/     padding: 0px 10px 0px 22px;      } div#bannerrow1 /* provides full-width color to top row in running head (requires script) */     {     background-color: #99ccff;     } div#titlerow /* provides non-scroll topic title area (requires script) */     {     width: 100%; /* Forces tables to have correct right margin */     padding: 0px 10px 0px 22px;      background-color: #99ccff;             } /* --------------------------------------------------                     HEADING STYLES -------------------------------------------------- */ h1, h2, h3, h4     {     font-family: 瀹嬩綋, Verdana, Arial, Helvetica, sans-serif;     margin-bottom: .4em;      margin-top: 1em;     font-weight: bold;     } h1     {     font-size: 120%;     margin-top: 0em;     } div#scrollyes h1 /* Changes font size for full-scrolling topic */     {     font-size: 150%;     } h2     {     font-size: 120%;     } h3     {     font-size: 115%;     } h4     {     font-size: 100%;     } .dtH1, .dtH2, .dtH3, .dtH4     {     margin-left: -18px;     } div#titlerow h1     {     margin-bottom: .2em     } /* --------------------------------------------------                      TEXT STYLES -------------------------------------------------- */ p     {     margin: .5em 0em .5em 0em;     } blockquote.dtBlock     {     margin: .5em 1.5em .5em 1.5em;     } div#dtHoverText     {     color: #000066;     } .normal     {     margin: .5em 0em .5em 0em;     } .fineprint     {     font-size: 110%; /* 90% of 70% */     } .indent     {     margin: .5em 1.5em .5em 1.5em;     } .topicstatus /* Topic Status Boilerplate class */     {     display: block;     color: red;     } /* --------------------------------------------------                      LABEL STYLES -------------------------------------------------- */ p.label     {     margin-top: 1em;     } p.labelproc     {     margin-top: 1em;     color: #000066;     } /* --------------------------------------------------                     GRAPHIC STYLES -------------------------------------------------- */ img     {     border: none;      } /* --------------------------------------------------                      LIST STYLES -------------------------------------------------- */ ol, ul     {     margin: .5em 0em 0em 2em;      } li     {     margin-bottom: .5em;     } ul p, ol p, dl p     {     margin-left: 0em;     } ul p.label, ol p.label     {     margin-top: .5em;     } /* --------------------------------------------------                DEFINITION LIST STYLES -------------------------------------------------- */ dl     {     margin-top: 0em;      padding-left: 1px; /* Prevents italic-letter descenders from being cut off */     } dd     {     margin-bottom: 0em;       margin-left: 1.5em;      } dt     {     margin-top: .5em;      } /* --------------------------------------------------            CODE, SYNTAX, and REFTIP STYLES -------------------------------------------------- */ pre     {     margin-top: .5em;     margin-bottom: .5em;      } pre, code, .code     {     font: 100% 瀹嬩綋, Courier New, Monospace, Courier;/* This is 100% of 70% */     color: #000066;     } pre b, code b     {     letter-spacing: .1em; /* opens kerning on bold in Syntax/Code */     } pre.syntax     {     font: 100% Courier New, 瀹嬩綋, Monospace, Courier;/* This is 100% of 70% */     background: #cccccc;     padding: 4px 8px;     cursor: text;     margin-top: 1em;     margin-bottom: 1em;      color: #000000;     border-width: 1px;     border-style: solid;     border-color: #999999;     } /* --------------------------------------------------                       LINK STYLES -------------------------------------------------- */ a:link     {     color: #0000ff;     } a:visited     {     color: #0000ff;     } a:hover     {     color: #3366ff;     } /* --------------------------- MSHelp\:link - Help HxLinks --------------------------- */ MSHelp\:link     {     text-decoration: underline;      color: #0000ff;      hoverColor: #3366ff;     filterString: ;     }     A.HxLinkTable /* MSHelp\:link - Table disambiguation elements */     {     } /* --------------------------- MSHelp\:ktable - Help links --------------------------- */ MSHelp\:ktable     {     disambiguator: span;     separator: &nbsp|&#32;     prefix: |&#32;     postfix: &nbsp;     filterString: ;     } div.HxLinkTable     {     width: auto; /* Forces tables to have correct right margins and top spacing */     margin-top: -.4em;     visibility: visible;     } ol div.HxLinkTable, ul div.HxLinkTable     {     margin-top: 0em; /* Forces tables to have correct right margins and top spacing */     } table.HxLinkTable /* Keep in sync with general table settings below */     {     width: auto;     margin-top: 1.5em;     margin-bottom: .3em;     margin-left: -1em;     border-width: 1px 1px 0px 0px;     border-style: solid;     border-color: #999999;     background-color: #999999;      font-size: 100%; /* Text in Table is same size as text outside table */     behavior:url(hxlinktable.htc); /* Attach the behavior to link elements. */     } table.HxLinkTable th, table.HxLinkTable td /* Keep in sync with general table settings below */     {      border-style: solid; /* Creates the cell border and color */     border-width: 0px 0px 1px 1px;     border-style: solid;     border-color: #999999;     padding: 4px 6px;     text-align: left;     } table.HxLinkTable th /* Keep in sync with general table settings below */     {      background: #cccccc; /* Creates the shaded table header row */     vertical-align: bottom;     } table.HxLinkTable td /* Keep in sync with general table settings below */     {     background: #ffffff;     vertical-align: top;     } /* --------------------------------------------------                     TABLE STYLES -------------------------------------------------- */ div.tablediv     {     width: 100%; /* Forces tables to have correct right margins and top spacing */     margin-top: -.4em;     } ol div.tablediv, ul div.tablediv, ol div.HxLinkTable, ul div.HxLinkTable     {     margin-top: 0em; /* Forces tables to have correct right margins and top spacing */     } table.dtTABLE     {     width: 100%; /* Forces tables to have correct right margin */     margin-top: .6em;     margin-bottom: .3em;     border-width: 1px 1px 0px 0px;     border-style: solid;     border-color: #999999;     background-color: #999999;      font-size: 100%; /* Text in Table is same size as text outside table */     } table.dtTABLE th, table.dtTABLE td     {      border-style: solid; /* Creates the cell border and color */     border-width: 0px 0px 1px 1px;     border-style: solid;     border-color: #999999;     padding: 4px 6px;     text-align: left;     } table.dtTABLE th         {      background: #cccccc; /* Creates the shaded table header row */     vertical-align: bottom;     } table.dtTABLE td         {     background: #ffffff;     vertical-align: top;     } /* -------------------------------------------------- ISSUE REPORTING AND MISC LINKS TOPIC FOOTER -------------------------------------------------- */ div.footer     {          } div.footer hr     {     color: #999999;     height: 1px;     } /* --------------------------------------------------              STYLES FOR RUNNING HEADS -------------------------------------------------- */ table.bannerparthead, table.bannertitle /* General values for the Running Head tables */     {     position: relative;     left: 0px;     top: 0px;     padding: 0px 0px 0px 0px;     margin: 0px 0px 0px 0px;     width: 100%;     height: 21px;      border-collapse: collapse;     border-style: solid;     border-width: 0px;     background-color: #99ccff;      font-size: 100%;     } table.bannerparthead td /* General Values for cells in the top row of running head */     {     margin: 0px 0px 0px 0px;     padding: 2px 0px 0px 4px;     vertical-align: middle;     /*border-width: 0px 0px 1px 0px; */     border-width: 0px     border-style: solid;     border-color: #999999;     background: transparent;      /* font-style: normal; */     font-weight: normal;     } table.bannerparthead td.product /* Values for top right cell in running head */     {                       /* Allows for a second text block in the running head */     text-align: right;     padding: 2px 5px 0px 5px;     } table.bannertitle td /* General Values for cells in the bottom row of running head */     {     margin: 0px 0px 0px 0px;     padding: 0px 0px 0px 3px;     vertical-align: middle;     border-width: 0px 0px 1px 0px;     border-style: solid;     border-color: #999999;     background: transparent;     font-weight: bold;     } td.button1 /* Values for button cells */     {     width: 14px;     cursor: hand;     } /* =================================================             STYLES REQUIRED BY THE SCRIPT */ /* --------------------------------------------------                   SAMPLE VIEWER -------------------------------------------------- */ div#smpMgrCell     {     display:none;     } table.SampMgr     {     margin: 0px 0px 0px -22px;     } table.SampMgr td     {     padding-left: 22px;     } /* -------------------------------------------------- RUNNING HEAD BAR POPUP STYLES: See Also, Requirements, MultiLang Filtering -------------------------------------------------- */ div.sapop, div.langMenu /* See Also & Requirements popups */     {     position: absolute;     left: 0px;     z-index: 1;     width: 50%;     padding: 0px 8px 5px 26px;     visibility: hidden;     border: 1px solid #999999; /* Same as all other border colors */     background: #ffffcc;     } div.langMenu /* MultiLang Filter popup */     {     padding: 10px 10px 10px 10px;     } div.langMenu ul     {     list-style-type: none;     padding-left: 5px;     margin-left: 0px;     } .lang, .ilang /* controls the multilang tag styles */     {     color: #333333;     font-family: Verdana, Arial, 瀹嬩綋, Helvetica, sans-serif;     font-size: 80%;     font-weight: normal;     font-style: normal;     } h1 .lang, h1 .ilang      {     font-size: 80%;     } div.filtered     {     margin-top: .6em;     margin-bottom: .6em;     margin-left: -7px;     padding: 0px 0px 0px 6px;     border-left: 1px solid #999999;     background: #ffffff;     } div.filtered h1, div.filtered h2, div.filtered h3, div.filtered h4     {     margin-left: -22px;     } div.filtered span.lang     {     position: relative;     left: 0px;     } /* --------------------------------------------------               PARAMETER POPUP STYLES -------------------------------------------------- */ div.reftip /* Defines the RefTip popup in Syntax */     {     position: absolute;     z-index: 1;     visibility: hidden;     border: 1px solid #999999;     background: #ffffcc; /*    padding: 0px 0px 0px 0px; */         } div.reftip dl /* Sets margin around the text within the popup */     {     margin: 3px 8px 8px 8px;     } a.synParam /* parameter popup links */     {     color: #0000ff; /* Must match the a:link style color */     text-decoration: underline;     } a.synParam:visited /* ensures parameter popup links are always the unvisited color */     {     color: #0000ff; /* Must match the a:link style color */     text-decoration: underline;     } a.synParam:hover /* parameter popup links */     {     color: #3366ff; /* Must match the a:hover style color */     text-decoration: underline;     font-style: italic;     } /* --------------------------------------------------               EXPAND-COLLAPSE STYLES -------------------------------------------------- */ div.expandBody     {     margin: .5em 0em 0em 1.4em;     display:none;     } a.expandLink1     {     font-size: 115%;      } a#ExPand     {     color: #3366ff;      font-weight: bold;      text-decoration: none;      } a#ExPandAll     {     color: #3366ff;      font-weight: bold;      text-decoration: none;      } /* --------------------------------------------------               GLOSSARY POPUP STYLES            Not used by Visual Studio .NET  -------------------------------------------------- */ /* COMMENT OUT GLOSSARY SECTION /*div#popUpWindow     { Controlled by the script in the variable L_PopUpBoxStyle_Style     }*/ a.glosslink:link     {     color: #000000;     } a.glosslink:visited     {     color: #000000;      } a.glosslink:hover     {     color: #000000;     font-style: italic;     } div#popUpWindow h5 /* Controls the style of the Term in Glossary Popups */     {     margin: 5px 5px 5px 5px;     color: #000000;     } div#popUpWindow p /* Controls the style of the Text in Glossary Popups */     {     margin: 5px 5px 5px 5px;     color: #000000;     } p.GLOSSARY_TEXT     {     } div#popUpWindow a /* Controls the style of the Links in Glossary Popups */     {     } */ /* END COMMENT OUT OF GLOSSARY SECTION */ /* END STYLES REQUIRED BY THE SCRIPT  ================================================== */ </style> <HEAD> <META HTTP-EQUIV="Content-Type" Content="text/html; charset=gb2312"> <TITLE>特殊字符</TITLE> <xml> <MSHelp:TOCTitle Title="特殊字符"/> <MSHelp:RLTitle Title="特殊字符 (JScript .NET)"/> <MSHelp:Keyword Index="A" Term="jsreconSpecialCharacters"/> <MSHelp:Keyword Index="A" Term="jsreconSpecialCharacters"/> <MSHelp:Keyword Index="K" Term="特殊字符, 搜索"/> <MSHelp:Keyword Index="K" Term="正則表達(dá)式, 字符匹配"/> <MSHelp:Keyword Index="K" Term="正則表達(dá)式中的字符匹配"/> <MSHelp:Attr Name="DevLang" Value="JScript"/> <MSHelp:Attr Name="DevLangVers" Value="kbJScript"/> <MSHelp:Attr Name="DocSet" Value="JScript"/> <MSHelp:Attr Name="DocSet" Value="Visual Studio"/> <MSHelp:Attr Name="Product" Value="VS"/> <MSHelp:Attr Name="ProductVers" Value="kbVS700"/> <MSHelp:Attr Name="Technology" Value="ManagedCode"/> <MSHelp:Attr Name="TechnologyVers" Value="kbManagedCode"/> <MSHelp:Attr Name="TopicType" Value="kbArticle"/> <MSHelp:Attr Name="TargetOS" Value="Windows"/> <MSHelp:Attr Name="Locale" Value="kbChineseSimp"/> </xml> <META name="rtfFileName" content="js7reregexp.rtf"> <META NAME="save" CONTENT="history">   <META NAME="msdnID" CONTENT="_731805"> </HEAD> <body topmargin=0 id="bodyID" class = "dtBODY"> <div   class="vvxyksv9kd"   id="nsbanner"> <div   class="vvxyksv9kd"   id="bannerrow1"> <TABLE CLASS="bannerparthead" CELLSPACING=0> <TR ID="hdr"> <TD CLASS="runninghead" nowrap>JScript .NET</TD> <TD CLASS="product" nowrap>&nbsp;</TD> </TR> </TABLE> </div> <div   class="vvxyksv9kd"   id="TitleRow"> <H1 class="dtH1"><A NAME="jsreconspecialcharacters"></A>特殊字符</H1> </div></div>  <div   class="vvxyksv9kd"   id="nstext" valign="bottom"> <P>許多元字符要求在試圖匹配它們時(shí)特別對(duì)待。若要匹配這些特殊字符，必須首先使字符"轉(zhuǎn)義"，即，將反斜杠字符 (\) 放在它們前面。下表列出了特殊字符以及它們的含義：</P> <div   id="vvxyksv9kd"   class="tablediv"><table cellspacing="0" class="dtTABLE"> <TR VALIGN="top"> <TH width=17%>特殊字符</TH> <TH width=83%>注釋</TH> </TR> <TR VALIGN="top"> <TD width=17%>$</TD> <TD width=83%>匹配輸入字符串結(jié)尾的位置。如果設(shè)置了 <B>RegExp</B> 對(duì)象的 <B>Multiline</B> 屬性，那么 $ 還匹配 \n 或 \r 前面的位置。若要匹配 $ 字符本身，請(qǐng)使用 \$。</TD> </TR> <TR VALIGN="top"> <TD width=17%>( )</TD> <TD width=83%>標(biāo)記子表達(dá)式的開始和結(jié)束?？梢圆东@子表達(dá)式以供以后使用。若要匹配這兩個(gè)字符，請(qǐng)使用 $ 和 $。</TD> </TR> <TR VALIGN="top"> <TD width=17%><B>*</B></TD> <TD width=83%>零次或多次匹配前面的字符或子表達(dá)式。若要匹配 * 字符，請(qǐng)使用 \*。</TD> </TR> <TR VALIGN="top"> <TD width=17%><B>+</B></TD> <TD width=83%>一次或多次匹配前面的字符或子表達(dá)式。若要匹配 + 字符，請(qǐng)使用 \+。</TD> </TR> <TR VALIGN="top"> <TD width=17%><B>.</B></TD> <TD width=83%>匹配除換行符 \n 之外的任何單個(gè)字符。若要匹配 .，請(qǐng)使用 \.。</TD> </TR> <TR VALIGN="top"> <TD width=17%>[ </TD> <TD width=83%>標(biāo)記中括號(hào)表達(dá)式的開始。若要匹配 [，請(qǐng)使用 \[。</TD> </TR> <TR VALIGN="top"> <TD width=17%>?</TD> <TD width=83%>零次或一次匹配前面的字符或子表達(dá)式，或指示"非貪心"限定符。若要匹配 ? 字符，請(qǐng)使用 \?。</TD> </TR> <TR VALIGN="top"> <TD width=17%>\</TD> <TD width=83%>將下一字符標(biāo)記為特殊字符、文本、反向引用或八進(jìn)制轉(zhuǎn)義符。例如，字符 n 匹配字符 n。\n 匹配換行符。序列 \\ 匹配 \，序列 \( 匹配 (。</TD> </TR> <TR VALIGN="top"> <TD width=17%>^</TD> <TD width=83%>匹配輸入字符串開始處的位置，但在中括號(hào)表達(dá)式中使用的情況除外，在那種情況下它對(duì)字符集求反。若要匹配 ^ 字符本身，請(qǐng)使用 \^。</TD> </TR> <TR VALIGN="top"> <TD width=17%>{</TD> <TD width=83%>標(biāo)記限定符表達(dá)式的開始。若要匹配 {，請(qǐng)使用 \{。</TD> </TR> <TR VALIGN="top"> <TD width=17%>|</TD> <TD width=83%>指出在兩個(gè)項(xiàng)之間進(jìn)行選擇。若要匹配 |，請(qǐng)使用 \|。</TD> </TR> </table></div> <H4 class="dtH4">請(qǐng)參見</H4> <P><A HREF="jsreconintroductiontoregularexpressions.htm">正則表達(dá)式介紹</A></P>  <div   id="vvxyksv9kd"   class="footer">  <HR> <p><A HREF="JavaScript:sendfeedback('CHS _731805', 'VSDOCS@MICROSOFT.COM')">將文檔反饋發(fā)送給 Microsoft</A></p> <p><MSHelp:link keywords="vxmscCopyright" TABINDEX="0">&copy; 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