正则表达式复习

   
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><font size="3"><font color="#000000"><span lang="EN-US">/<span style=""> </span></span><span style="">将下一个字符标记为一个特殊字符、或一个原义字符、或一个</span> <span style="">向后引用、或一个八进制转义符。例如，</span><span lang="EN-US">'n' </span><span style="">匹配字符</span><span lang="EN-US"> "n"</span><span style="">。</span><span lang="EN-US">'/n' </span><span style="">匹配一个换行符。序列</span><span lang="EN-US"> '//' </span><span style="">匹配</span><span lang="EN-US"> "/" </span><span style="">而</span><span lang="EN-US"> "/(" </span><span style="">则匹配</span><span lang="EN-US"> "("</span><span style="">。</span><span lang="EN-US"> </span></font></font>

<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><font size="3"><font color="#000000"><span lang="EN-US">$<span style=""> </span></span><span style="">匹配输入字符串的结束位置。如果设置了</span><span lang="EN-US">RegExp </span><span style="">对象的</span><span lang="EN-US"> Multiline </span><span style="">属性，</span><span lang="EN-US">$ </span><span style="">也匹配</span><span lang="EN-US"> '/n' </span><span style="">或</span><span lang="EN-US"> '/r' </span><span style="">之前的位置。</span><span lang="EN-US"> </span></font></font>

<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><font size="3"><font color="#000000"><span lang="EN-US">+<span style=""> </span></span><span style="">匹配前面的子表达式一次或多次。例如，</span><span lang="EN-US">'zo+' </span><span style="">能匹配</span><span lang="EN-US"> "zo" </span><span style="">以及</span><span lang="EN-US"> "zoo"</span><span style="">，但不能匹配</span><span lang="EN-US"> "z"</span><span style="">。</span><span lang="EN-US">+ </span><span style="">等价于</span><span lang="EN-US"> {1,}</span><span style="">。</span><span lang="EN-US"> </span></font></font>

<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><font size="3"><font color="#000000"><span lang="EN-US">{n}<span style=""> </span>n </span><span style="">是一个非负整数。匹配确定的</span><span lang="EN-US"> n </span><span style="">次。例如，</span><span lang="EN-US">'o{2}' </span><span style="">不能匹配</span><span lang="EN-US"> "Bob" </span><span style="">中的</span><span lang="EN-US"> 'o'</span><span style="">，但是能匹配</span><span lang="EN-US"> "food" </span><span style="">中的两个</span><span lang="EN-US"> o</span><span style="">。</span><span lang="EN-US"> </span></font></font>

<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><font size="3"><font color="#000000"><span lang="EN-US">{n,m}<span style=""> </span>m </span><span style="">和</span><span lang="EN-US"> n </span><span style="">均为非负整数，其中</span><span lang="EN-US">n <= m</span><span style="">。最少匹配</span><span lang="EN-US"> n </span><span style="">次且最多匹配</span><span lang="EN-US"> m </span><span style="">次。例如，</span><span lang="EN-US">"o{1,3}" </span><span style="">将匹配</span><span lang="EN-US"> "fooooood" </span><span style="">中的前三个</span><span lang="EN-US"> o</span><span style="">。</span><span lang="EN-US">'o{0,1}' </span><span style="">等价于</span><span lang="EN-US"> 'o?'</span><span style="">。请注意在逗号和两个数之间不能有空格。</span><span lang="EN-US"> </span></font></font>

<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><font size="3"><font color="#000000"><span lang="EN-US">.<span style=""> </span></span><span style="">匹配除</span><span lang="EN-US"> "/n" </span><span style="">之外的任何单个字符。要匹配包括</span><span lang="EN-US"> '/n' </span><span style="">在内的任何字符，请使用象</span><span lang="EN-US"> '[./n]' </span><span style="">的模式。</span><span lang="EN-US"> </span></font></font>

<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><font size="3"><font color="#000000"><span lang="EN-US">(?:pattern)<span style=""> </span></span><span style="">匹配</span><span lang="EN-US"> pattern </span><span style="">但不获取匹配结果，也就是说这是一个非获取匹配，不进行存储供以后使用。这在使用</span><span lang="EN-US"> "</span><span style="">或</span><span lang="EN-US">" </span><span style="">字符</span><span lang="EN-US"> (|) </span><span style="">来组合一个模式的各个部分是很有用。例如，</span><span lang="EN-US"> 'industr(?:y|ies) </span><span style="">就是一个比</span><span lang="EN-US"> 'industry|industries' </span><span style="">更简略的表达式。</span><span lang="EN-US"> </span></font></font>

<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><font size="3"><font color="#000000"><span lang="EN-US">(?!pattern)<span style=""> </span></span><span style="">负向预查，在任何不匹配</span><span lang="EN-US"> pattern </span><span style="">的字符串开始处匹配查找字符串。这是一个非获取匹配，也就是说，该匹配不需要获取供以后使用。例如</span><span lang="EN-US">'Windows (?!95|98|NT|2000)' </span><span style="">能匹配</span><span lang="EN-US"> "Windows 3.1" </span><span style="">中的</span><span lang="EN-US"> "Windows"</span><span style="">，但不能匹配</span><span lang="EN-US"> "Windows 2000" </span><span style="">中的</span><span lang="EN-US"> "Windows"</span><span style="">。预查不消耗字符，也就是说，在一个匹配发生后，在最后一次匹配之后立即开始下一次匹配的搜索，而不是从包含预查的字符之后开始</span><span lang="EN-US"> </span></font></font>

<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><font size="3"><font color="#000000"><span lang="EN-US">[xyz]<span style=""> </span></span><span style="">字符集合。匹配所包含的任意一个字符。例如，</span><span lang="EN-US"> '[abc]' </span><span style="">可以匹配</span><span lang="EN-US"> "plain" </span><span style="">中的</span><span lang="EN-US"> 'a'</span><span style="">。</span><span lang="EN-US"> </span></font></font>

<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><font size="3"><font color="#000000"><span lang="EN-US">[a-z]<span style=""> </span></span><span style="">字符范围。匹配指定范围内的任意字符。例如，</span><span lang="EN-US">'[a-z]' </span><span style="">可以匹配</span><span lang="EN-US"> 'a' </span><span style="">到</span><span lang="EN-US"> 'z' </span><span style="">范围内的任意小写字母字符。</span><span lang="EN-US"> </span></font></font>

<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><font size="3"><font color="#000000"><span lang="EN-US">/b<span style=""> </span></span><span style="">匹配一个单词边界，也就是指单词和空格间的位置。例如，</span><span lang="EN-US"> 'er/b' </span><span style="">可以匹配</span><span lang="EN-US">"never" </span><span style="">中的</span><span lang="EN-US"> 'er'</span><span style="">，但不能匹配</span><span lang="EN-US"> "verb" </span><span style="">中的</span><span lang="EN-US"> 'er'</span><span style="">。</span><span lang="EN-US"> </span></font></font>

<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><font size="3"><font color="#000000"><span lang="EN-US">/cx<span style=""> </span></span><span style="">匹配由</span><span lang="EN-US"> x </span><span style="">指明的控制字符。例如，</span><span lang="EN-US"> /cM </span><span style="">匹配一个</span><span lang="EN-US"> Control-M </span><span style="">或回车符。</span><span lang="EN-US">x </span><span style="">的值必须为</span><span lang="EN-US"> A-Z </span><span style="">或</span><span lang="EN-US"> a-z </span><span style="">之一。否则，将</span><span lang="EN-US"> c </span><span style="">视为一个原义的</span><span lang="EN-US"> 'c' </span><span style="">字符。</span><span lang="EN-US"> </span></font></font>

<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><font size="3"><font color="#000000"><span lang="EN-US">/D<span style=""> </span></span><span style="">匹配一个非数字字符。等价于</span><span lang="EN-US"> [^0-9]</span><span style="">。</span><span lang="EN-US"> </span></font></font>

<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><font size="3"><font color="#000000"><span lang="EN-US">/n<span style=""> </span></span><span style="">匹配一个换行符。等价于</span><span lang="EN-US"> /x<chmetcnv w:st="on" tcsc="0" numbertype="1" negative="False" hasspace="False" sourcevalue="0" unitname="a">0a</chmetcnv></span><span style="">和</span><span lang="EN-US"> /cJ</span><span style="">。</span><span lang="EN-US"> </span></font></font>

<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><font size="3"><font color="#000000"><span lang="EN-US">/s<span style=""> </span></span><span style="">匹配任何空白字符，包括空格、制表符、换页符等等。等价于</span><span lang="EN-US"> [ /f/n/r/t/v]</span><span style="">。</span><span lang="EN-US"> </span></font></font>

<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><font size="3"><font color="#000000"><span lang="EN-US">/t<span style=""> </span></span><span style="">匹配一个制表符。等价于</span><span lang="EN-US"> /x09 </span><span style="">和</span><span lang="EN-US"> /cI</span><span style="">。</span><span lang="EN-US"> </span></font></font>

<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><font size="3"><font color="#000000"><span lang="EN-US">/w<span style=""> </span></span><span style="">匹配包括下划线的任何单词字符。等价于</span><span lang="EN-US">'[A-Za-z0-9_]'</span><span style="">。</span><span lang="EN-US"> </span></font></font>

<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><font size="3"><font color="#000000"><span lang="EN-US">/xn<span style=""> </span></span><span style="">匹配</span><span lang="EN-US"> n</span><span style="">，其中</span><span lang="EN-US"> n </span><span style="">为十六进制转义值。十六进制转义值必须为确定的两个数字长。例如，</span><span lang="EN-US">'/x41' </span><span style="">匹配</span><span lang="EN-US"> "A"</span><span style="">。</span><span lang="EN-US">'/x041' </span><span style="">则等价于</span><span lang="EN-US"> '/x04' &amp; "1"</span><span style="">。正则表达式中可以使用</span><span lang="EN-US"> ASCII </span><span style="">编码。</span><span lang="EN-US">. </span></font></font>

<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><font size="3"><font color="#000000"><span lang="EN-US">/n<span style=""> </span></span><span style="">标识一个八进制转义值或一个向后引用。如果</span><span lang="EN-US"> /n </span><span style="">之前至少</span><span lang="EN-US"> n </span><span style="">个获取的子表达式，则</span><span lang="EN-US"> n </span><span style="">为向后引用。否则，如果</span><span lang="EN-US"> n </span><span style="">为八进制数字</span><span lang="EN-US"> (0-7)</span><span style="">，则</span><span lang="EN-US"> n </span><span style="">为一个八进制转义值。</span><span lang="EN-US"> </span></font></font>

<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><font size="3"><font color="#000000"><span lang="EN-US">/nml<span style=""> </span></span><span style="">如果</span><span lang="EN-US"> n </span><span style="">为八进制数字</span><span lang="EN-US"> (0-3)</span><span style="">，且</span><span lang="EN-US"> m </span><span style="">和</span><span lang="EN-US"> l </span><span style="">均为八进制数字</span><span lang="EN-US"> (0-7)</span><span style="">，则匹配八进制转义值</span><span lang="EN-US"> nml</span><span style="">。</span><span lang="EN-US"> </span></font></font>

 

评论

1 楼 wolf_awp 2011-12-13  

这种东西都可以上首页，唉！