n="top"><p>keep(expr) is equivalent to the perl (?&gt;...) extension.</p></td></tr>
</table></div>
<p>

</p>
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<td><p><span class="term">Parameters:</span></p></td>
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<td><p><span class="term"><code class="computeroutput">expr</code></span></p></td>
<td><p>The sub-expression to modify. </p></td>
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