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<TITLE>Matching Line Boundaries in a Regular Expression
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<B><A HREF="../java.util.regex/pkg.html">java.util.regex</A></B><font color="#666666" SIZE="-2">
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<h3>
e443.
Matching Line Boundaries in a Regular Expression</h3>
By default, the beginning-of-line matcher (^) and end-of-line matcher
($) do not match at line boundaries. They match the beginning and end
of the entire input sequence. For example, the pattern <code>^a</code> matches
<code>abc</code> but does not match <code>def\nabc</code>. To enable <code>^</code> and
<code>$</code> to match line boundaries, the pattern should be compiled with
the multiline flag enabled.
<P> It is also possible to enable multiline mode within a pattern
using the inline modifier <code>(?m)</code>. For example, multiline mode is
enabled in the pattern <code>(?m)^a</code>. Multiline mode can be disabled
using <code>(?-m)</code>.
<pre>
CharSequence inputStr = <font color="#0066ff"><i>"abc\ndef"</i></font>;
String patternStr = <font color="#0066ff"><i>"abc$"</i></font>;
// Compile with multiline enabled
Pattern pattern = Pattern.compile(patternStr, Pattern.MULTILINE);
Matcher matcher = pattern.matcher(inputStr);
boolean matchFound = matcher.find(); // true
// Use an inline modifier to enable multiline mode
matchFound = pattern.matches(<font color="#0066ff"><i>".*abc$.*"</i></font>, <font color="#0066ff"><i>"abc\r\ndef"</i></font>); // false
matchFound = pattern.matches(<font color="#0066ff"><i>"(?m).*abc$.*"</i></font>, <font color="#0066ff"><i>"abc\r\ndef"</i></font>); // true
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Related Examples
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e441. <a class="eglink" href="LineFilter.html?l=rel">
Using a Regular Expression to Filter Lines from a Reader
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e442. <a class="eglink" href="LineFilter2.html?l=rel">
Implementing a FilterReader to Filter Lines Based on a Regular Expression
</a>
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e444. <a class="eglink" href="Lines.html?l=rel">
Matching Across Line Boundaries in a Regular Expression
</a>
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e445. <a class="eglink" href="ReadLine.html?l=rel">
Reading Lines from a String Using a Regular Expression
</a>
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e446. <a class="eglink" href="RemLine.html?l=rel">
Removing Line Termination Characters from a String
</a>
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See also:
<a class="eglink" href="/egs/java.util.regex/pkg.html?l=rel#Flags">
Flags
</a>
<a class="eglink" href="/egs/java.util.regex/pkg.html?l=rel#Groups">
Groups
</a>
<a class="eglink" href="/egs/java.util.regex/pkg.html?l=rel#Paragraphs">
Paragraphs
</a>
<a class="eglink" href="/egs/java.util.regex/pkg.html?l=rel#Searching%20and%20Replacing">
Searching and Replacing
</a>
<a class="eglink" href="/egs/java.util.regex/pkg.html?l=rel#Tokenizing">
Tokenizing
</a>
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