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<?xml version="1.0" encoding="UTF-8"?>
<!--
* Scilab ( http://www.scilab.org/ ) - This file is part of Scilab
* Copyright (C) INRIA
*
* This file must be used under the terms of the CeCILL.
* This source file is licensed as described in the file COPYING, which
* you should have received as part of this distribution. The terms
* are also available at
* http://www.cecill.info/licences/Licence_CeCILL_V2-en.txt
*
-->
<refentry version="5.0-subset Scilab" xml:id="grep" xml:lang="en"
xmlns="http://docbook.org/ns/docbook"
xmlns:xlink="http://www.w3.org/1999/xlink"
xmlns:svg="http://www.w3.org/2000/svg"
xmlns:ns5="http://www.w3.org/1999/xhtml"
xmlns:mml="http://www.w3.org/1998/Math/MathML"
xmlns:db="http://docbook.org/ns/docbook">
<info>
<pubdate>$LastChangedDate: 2008-01-07 16:57:13 +0200 (Mon, 07 Jan
2008)$</pubdate>
</info>
<refnamediv>
<refname>grep</refname>
<refpurpose>find matches of a string in a vector of strings</refpurpose>
</refnamediv>
<refsynopsisdiv>
<title>Calling Sequence</title>
<synopsis>row=grep(haystack,needle )
[row,which]=grep(haystack,needle )
row=grep(haystack,needle ,[flag])
[row,which]=grep(haystack,needle ,[flag])</synopsis>
</refsynopsisdiv>
<refsection>
<title>Parameters</title>
<variablelist>
<varlistentry>
<term>haystack</term>
<listitem>
<para>A Row vector of character strings.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>needle</term>
<listitem>
<para>A character string or a row vector of character strings . The
string(s) to search in <literal>haystack.</literal></para>
</listitem>
</varlistentry>
<varlistentry>
<term>row</term>
<listitem>
<para>vector of indices: row where a match has been found or an
empty matrix if no match found.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>which</term>
<listitem>
<para>vector of indices: index of needle string found or an empty
matrix if no match found.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>flag</term>
<listitem>
<para>Character ("r" for regular expression)</para>
</listitem>
</varlistentry>
</variablelist>
</refsection>
<refsection>
<title>Description</title>
<para>Foreach entry of <literal>haystack </literal>, grep searches if at
least a string in <literal>needle</literal> which matches a substring.
The <literal>haystack</literal> entries index where at least a match has
been found are returned in the <literal>row</literal> output argument.
The optionnal <literal>which</literal> output argument gives the index
of first string of <literal>needle</literal> found.</para>
<para>When using the third parameter <literal>flag="r"</literal>, the
<literal>needle</literal> is expected to be a regular expression string.
In this case, <literal>grep</literal> uses the
<literal>needle</literal> as a regular expression and compares it
against <literal>haystack</literal> according to the regular express
rules. See the <link linkend="regexp">regexp</link> function for details about
regular expressions.</para>
</refsection>
<refsection>
<title>Example #1</title>
<para>In the following example, we search one or two strings in a text,
which is stored in the <literal>txt</literal> variable.</para>
<programlisting role="example"><![CDATA[
txt=['find matches of a string in a vector of strings'
'search position of a character string in an other string'
'Compare Strings'];
grep(txt,'strings')
grep(txt,['strings' 'Strings'])
[r,w]=grep(txt,['strings' 'Strings'])
]]></programlisting>
</refsection>
<refsection>
<title>Example #2</title>
<para>In the following example, we perform regexp searches.</para>
<programlisting role="example"><![CDATA[
str = ["hat";"cat";"hhat";"chat";"hcat";"ccchat";"at";"dog"]
grep(str,'/[hc]+at/','r')
grep(str,'/[hc]?at/','r')
grep(str,'/cat|dog/','r')
]]></programlisting>
</refsection>
<refsection>
<title>See Also</title>
<simplelist type="inline">
<member><link linkend="strindex">strindex</link></member>
<member><link linkend="regexp">regexp</link></member>
</simplelist>
</refsection>
</refentry>
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