php-doc-en/reference/strings/functions/ord.xml
2020-12-05 14:30:42 +00:00

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<?xml version="1.0" encoding="utf-8"?>
<!-- $Revision$ -->
<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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