php-doc-en/reference/strings/functions/substr-count.xml

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<!-- splitted from ./en/functions/strings.xml, last change in rev 1.27 -->
<refentry xml:id="function.substr-count" xmlns="http://docbook.org/ns/docbook">
 <refnamediv>
  <refname>substr_count</refname>
  <refpurpose>Count the number of substring occurrences</refpurpose>
 </refnamediv>
 <refsect1 role="description">
  &reftitle.description;
  <methodsynopsis>
   <type>int</type><methodname>substr_count</methodname>
   <methodparam><type>string</type><parameter>haystack</parameter></methodparam>
   <methodparam><type>string</type><parameter>needle</parameter></methodparam>
   <methodparam choice="opt"><type>int</type><parameter>offset</parameter><initializer>0</initializer></methodparam>
   <methodparam choice="opt"><type class="union"><type>int</type><type>null</type></type><parameter>length</parameter><initializer>&null;</initializer></methodparam>
  </methodsynopsis>
  <para>
   <function>substr_count</function> returns the number of times the
   <parameter>needle</parameter> substring occurs in the
   <parameter>haystack</parameter> string. Please note that
   <parameter>needle</parameter> is case sensitive.
  </para>
  <note>
   <para>
    This function doesn't count overlapped substrings. See the example below!
   </para>
  </note>
 </refsect1>

 <refsect1 role="parameters">
  &reftitle.parameters;
  <para>
   <variablelist>
    <varlistentry>
     <term><parameter>haystack</parameter></term>
     <listitem>
      <para>
       The string to search in
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>needle</parameter></term>
     <listitem>
      <para>
       The substring to search for
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>offset</parameter></term>
     <listitem>
      <para>
       The offset where to start counting. If the offset is negative, counting
       starts from the end of the string.
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>length</parameter></term>
     <listitem>
      <para>
       The maximum length after the specified offset to search for the
       substring. It outputs a warning if the offset plus the length is
       greater than the <parameter>haystack</parameter> length.
       A negative length counts from the end of <parameter>haystack</parameter>.
      </para>
     </listitem>
    </varlistentry>
   </variablelist>
  </para>
 </refsect1>

 <refsect1 role="returnvalues">
  &reftitle.returnvalues;
  <para>
   This function returns an <type>int</type>.
  </para>
 </refsect1>

 <refsect1 role="changelog">
  &reftitle.changelog;
  <para>
   <informaltable>
    <tgroup cols="2">
     <thead>
      <row>
       <entry>&Version;</entry>
       <entry>&Description;</entry>
      </row>
     </thead>
     <tbody>
     <row>
      <entry>8.0.0</entry>
      <entry>
       <parameter>length</parameter> is nullable now.
      </entry>
     </row>
      <row>
       <entry>7.1.0</entry>
       <entry>
        Support for negative <parameter>offset</parameter>s and <parameter>length</parameter>s has been added.
        <parameter>length</parameter> may also be <literal>0</literal> now.
       </entry>
      </row>
     </tbody>
    </tgroup>
   </informaltable>
  </para>
 </refsect1>

 <refsect1 role="examples">
  &reftitle.examples;
  <para>
   <example>
    <title>A <function>substr_count</function> example</title>
    <programlisting role="php">
<![CDATA[
<?php
$text = 'This is a test';
echo strlen($text); // 14

echo substr_count($text, 'is'); // 2

// the string is reduced to 's is a test', so it prints 1
echo substr_count($text, 'is', 3);

// the text is reduced to 's i', so it prints 0
echo substr_count($text, 'is', 3, 3);

// generates a warning because 5+10 > 14
echo substr_count($text, 'is', 5, 10);


// prints only 1, because it doesn't count overlapped substrings
$text2 = 'gcdgcdgcd';
echo substr_count($text2, 'gcdgcd');
?>
]]>
    </programlisting>
   </example>
  </para>
 </refsect1>

 <refsect1 role="seealso">
  &reftitle.seealso;
  <para>
   <simplelist>
    <member><function>count_chars</function></member>
    <member><function>strpos</function></member>
    <member><function>substr</function></member>
    <member><function>strstr</function></member>
   </simplelist>
  </para>
 </refsect1>
</refentry>
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