php-doc-en/reference/strings/functions/ord.xml

<?xml version="1.0" encoding="utf-8"?>
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<refentry xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://docbook.org/ns/docbook" xml:id="function.ord">
 <refnamediv>
  <refname>ord</refname>
  <refpurpose>Convert the first byte of a string to a value between 0 and 255</refpurpose>
 </refnamediv>
 
 <refsect1 role="description">
  &reftitle.description;
  <methodsynopsis>
   <type>int</type><methodname>ord</methodname>
   <methodparam><type>string</type><parameter>character</parameter></methodparam>
  </methodsynopsis>
  <para>
   Interprets the binary value of the first byte of
   <parameter>character</parameter> as an unsigned integer between 0 and 255.
  </para>
  <para>
   If the string is in a single-byte encoding, such as ASCII, ISO-8859, or Windows 1252, this is equivalent to returning the position of a character in the character set's mapping table. However, note that this function is not aware of any string encoding, and in particular will never identify a Unicode code point in a multi-byte encoding such as UTF-8 or UTF-16.
  </para>
  <para>
   This function complements <function>chr</function>.
  </para>
 </refsect1>

 <refsect1 role="parameters">
  &reftitle.parameters;
  <para>
   <variablelist>
    <varlistentry>
     <term><parameter>character</parameter></term>
     <listitem>
      <para>
       A character.
      </para>
     </listitem>
    </varlistentry>
   </variablelist>
  </para>
 </refsect1>

 <refsect1 role="returnvalues">
  &reftitle.returnvalues;
  <para>
   An integer between 0 and 255.
  </para>
 </refsect1>

 <refsect1 role="examples">
  &reftitle.examples;
  <para>
   <example>
    <title><function>ord</function> example</title>
    <programlisting role="php">
<![CDATA[
<?php
$str = "\n";
if (ord($str) == 10) {
    echo "The first character of \$str is a line feed.\n";
}
?>
]]>
    </programlisting>
   </example>
 </para>
 <para> 
   <example>
    <title>Examining the individual bytes of a UTF-8 string</title>
    <programlisting role="php">
<![CDATA[
<?php
declare(encoding='UTF-8');
$str = "🐘";
for ( $pos=0; $pos < strlen($str); $pos ++ ) {
 $byte = substr($str, $pos);
 echo 'Byte ' . $pos . ' of $str has value ' . ord($byte) . PHP_EOL;
}
?>
]]>
    </programlisting>
    &example.outputs;
    <screen>
Byte 0 of $str has value 240
Byte 1 of $str has value 159
Byte 2 of $str has value 144
Byte 3 of $str has value 152
    </screen>
   </example>
  </para>
 </refsect1>

 <refsect1 role="seealso">
  &reftitle.seealso;
  <para>
   <simplelist>
    <member><function>chr</function></member>
    <member>An <link xlink:href="&url.asciitable;">ASCII-table</link></member>
    <member><function>mb_ord</function></member>
   </simplelist>
  </para>
 </refsect1>

</refentry>
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