pattern.html

C++正则表达式解析

<code>\s</code>
</td>
<td>
<code>[&nbsp;\t\r\n\x0B]</code>
</td>
</tr>
<tr>
<td>
<code>\S</code>
</td>
<td>
<code>[^\s]</code>
</td>
</tr>
<tr>
<td>
<code>\w</code>
</td>
<td>
<code>[a-zA-Z0-9_]</code>
</td>
</tr>
<tr>
<td>
<code>\W</code>
</td>
<td>
<code>[^\w]</code>
</td>
</tr>
<tr>
<td colspan="2">
&nbsp;
</td>
</tr>
<tr>
<td colspan="2">
<b>POSIX character classes
</td>
</tr>
<tr>
<td>
<code>\p{Lower}</code>
</td>
<td>
<code>[a-z]</code>
</td>
</tr>
<tr>
<td>
<code>\p{Upper}</code>
</td>
<td>
<code>[A-Z]</code>
</td>
</tr>
<tr>
<td>
<code>\p{ASCII}</code>
</td>
<td>
<code>[\x00-\x7F]</code>
</td>
</tr>
<tr>
<td>
<code>\p{Alpha}</code>
</td>
<td>
<code>[a-zA-Z]</code>
</td>
</tr>
<tr>
<td>
<code>\p{Digit}</code>
</td>
<td>
<code>[0-9]</code>
</td>
</tr>
<tr>
<td>
<code>\p{Alnum}</code>
</td>
<td>
<code>[\w&&[^_]]</code>
</td>
</tr>
<tr>
<td>
<code>\p{Punct}</code>
</td>
<td>
<code>[!"#$%&'()*+,-./:;&lt;=&gt;?@[\]^_`{|}~]</code>
</td>
</tr>
<tr>
<td>
<code>\p{XDigit}</code>
</td>
<td>
<code>[a-fA-F0-9]</code>
</td>
</tr>
<tr>
<td colspan="2">
&nbsp;
</td>
</tr>
<tr>
<td colspan="2">
<b>Boundary Matches</b>
</td>
</tr>
<tr>
<td>
<code>^</code>
</td>
<td>
The beginning of a line. Also matches the beginning of input.
</td>
</tr>
<tr>
<td>
<code>$</code>
</td>
<td>
The end of a line. Also matches the end of input.
</td>
</tr>
<tr>
<td>
<code>\b</code>
</td>
<td>
A word boundary
</td>
</tr>
<tr>
<td>
<code>\B</code>
</td>
<td>
A non word boundary
</td>
</tr>
<tr>
<td>
<code>\A</code>
</td>
<td>
The beginning of input
</td>
</tr>
<tr>
<td>
<code>\G</code>
</td>
<td>
The end of the previous match. Ensures that a "next" match will only
happen if it begins with the character immediately following the end of
the "current" match.
</td>
</tr>
<tr>
<td>
<code>\Z</code>
</td>
<td>
The end of input. Will also match if there is a single trailing
<code>\r\n</code>, a single trailing <code>\r</code>, or a single
trailing <code>\n</code>.
</td>
</tr>
<tr>
<td>
<code>\z</code>
</td>
<td>
The end of input
</td>
</tr>
<tr>
<td>
&nbsp;
</td>
</tr>
<tr>
<td colspan="2">
<b>Greedy Quantifiers</b>
</td>
</tr>
<tr>
<td>
<code><i>x?</i></code>
</td>
<td>
<i>x</i>, either zero times or one time
</td>
</tr>
<tr>
<td>
<code><i>x*</i></code>
</td>
<td>
<i>x</i>, zero or more times
</td>
</tr>
<tr>
<td>
<code><i>x+</i></code>
</td>
<td>
<i>x</i>, one or more times
</td>
</tr>
<tr>
<td>
<code><i>x{n}</i></code>
</td>
<td>
<i>x</i>, exactly n times
</td>
</tr>
<tr>
<td>
<code><i>x{n,}</i></code>
</td>
<td>
<i>x</i>, at least <code><i>n</i></code> times
</td>
</tr>
<tr>
<td>
<code><i>x{,m}</i></code>
</td>
<td>
<i>x</i>, at most <code><i>m</i></code> times
</td>
</tr>
<tr>
<td>
<code><i>x{n,m}</i></code>
</td>
<td>
<i>x</i>, at least <code><i>n</i></code> times and at most
<code><i>m</i></code> times
</td>
</tr>
<tr>
<td>
&nbsp;
</td>
</tr>
<tr>
<td colspan="2">
<b>Possessive Quantifiers</b>
</td>
</tr>
<tr>
<td>
<code><i>x?+</i></code>
</td>
<td>
<i>x</i>, either zero times or one time
</td>
</tr>
<tr>
<td>
<code><i>x*+</i></code>
</td>
<td>
<i>x</i>, zero or more times
</td>
</tr>
<tr>
<td>
<code><i>x++</i></code>
</td>
<td>
<i>x</i>, one or more times
</td>
</tr>
<tr>
<td>
<code><i>x{n}+</i></code>
</td>
<td>
<i>x</i>, exactly n times
</td>
</tr>
<tr>
<td>
<code><i>x{n,}+</i></code>
</td>
<td>
<i>x</i>, at least <code><i>n</i></code> times
</td>
</tr>
<tr>
<td>
<code><i>x{,m}+</i></code>
</td>
<td>
<i>x</i>, at most <code><i>m</i></code> times
</td>
</tr>
<tr>
<td>
<code><i>x{n,m}+</i></code>
</td>
<td>
<i>x</i>, at least <code><i>n</i></code> times and at most
<code><i>m</i></code> times
</td>
</tr>
<tr>
<td colspan="2">
&nbsp;
</td>
</tr>
<tr>
<td colspan="2">
<b>Reluctant Quantifiers</b>
</td>
</tr>
<tr>
<td>
<code><i>x??</i></code>
</td>
<td>
<i>x</i>, either zero times or one time
</td>
</tr>
<tr>
<td>
<code><i>x*?</i></code>
</td>
<td>
<i>x</i>, zero or more times
</td>
</tr>
<tr>
<td>
<code><i>x+?</i></code>
</td>
<td>
<i>x</i>, one or more times
</td>
</tr>
<tr>
<td>
<code><i>x{n}?</i></code>
</td>
<td>
<i>x</i>, exactly n times
</td>
</tr>
<tr>
<td>
<code><i>x{n,}?</i></code>
</td>
<td>
<i>x</i>, at least <code><i>n</i></code> times
</td>
</tr>
<tr>
<td>
<code><i>x{,m}?</i></code>
</td>
<td>
<i>x</i>, at most <code><i>m</i></code> times
</td>
</tr>
<tr>
<td>
<code><i>x{n,m}?</i></code>
</td>
<td>
<i>x</i>, at least <code><i>n</i></code> times and at most
<code><i>m</i></code> times
</td>
</tr>
<tr>
<td>
&nbsp;
</td>
</tr>
<tr>
<td colspan="2">
<b>Operators</b>
</td>
</tr>
<tr>
<td>
<code><i>xy</i></code>
</td>
<td>
<code><i>x</i></code> then <code><i>y</i></code>
</td>
</tr>
<tr>
<td>
<code><i>x</i></code>|<code><i>y</i></code>
</td>
<td>
<code><i>x</i></code> or <code><i>y</i></code>
</td>
</tr>
<tr>
<td>
<code>(<i>x</i>)</code>
</td>
<td>
<code><i>x</i></code> as a capturing group
</td>
</tr>
<tr>