As ord() doesn't work with utf-8, and if you do not have access to mb_* functions, the following function will work well:
<?php
function ordutf8($string, &$offset) {
$code = ord(substr($string, $offset,1));
if ($code >= 128) { //otherwise 0xxxxxxx
if ($code < 224) $bytesnumber = 2; //110xxxxx
else if ($code < 240) $bytesnumber = 3; //1110xxxx
else if ($code < 248) $bytesnumber = 4; //11110xxx
$codetemp = $code - 192 - ($bytesnumber > 2 ? 32 : 0) - ($bytesnumber > 3 ? 16 : 0);
for ($i = 2; $i <= $bytesnumber; $i++) {
$offset ++;
$code2 = ord(substr($string, $offset, 1)) - 128; //10xxxxxx
$codetemp = $codetemp*64 + $code2;
}
$code = $codetemp;
}
$offset += 1;
if ($offset >= strlen($string)) $offset = -1;
return $code;
}
?>
$offset is a reference, as it is not easy to split a utf-8 char-by-char. Useful to iterate on a string:
<?php
$text = "abcàê߀abc";
$offset = 0;
while ($offset >= 0) {
echo $offset.": ".ordutf8($text, $offset)."\n";
}
/* returns:
0: 97
1: 98
2: 99
3: 224
5: 234
7: 223
9: 8364
12: 97
13: 98
14: 99
*/
?>
Feel free to adapt my code to fit your needs.
ord
(PHP 4, PHP 5, PHP 7, PHP 8)
ord — Konvertiert das erste Byte einer Zeichenkette in einen Wert zwischen 0 und 255
Beschreibung
ord
( string
$character
) : int
Interpretiert den ASCII-Wert des ersten Bytes von
character als vorzeichenlose Ganzzahl zwischen 0 und
255.
Liegt die Zeichenkette in einer Ein-Byte-Kodierung, wie ASCII, ISO-8859 oder Windows 1252, vor, ist dies gleichwertig zur Rückgabe der Position des Zeichens in der Zuordnungstabelle des Zeichensatzes. Allerdings ist zu beachten, dass diese Funktion keine Zeichenkettenkodierung kennt, und insbesondere niemals einen Unicode-Codepoint in einer Multibyte-Kodierung wie UTF-8 oder UTF-16 erkennt.
Die Funktion ist das Gegenstück zu chr().
Parameter-Liste
-
character -
Ein Zeichen.
Rückgabewerte
Ein Integer zwischen 0 und 255.
Beispiele
Beispiel #1 ord()-Beispiel
<?php
$str = "\n";
if (ord($str) == 10) {
echo "Das erste Zeichen von \$str ist ein Zeilenvorschub.\n";
}
?>
Beispiel #2 Untersuchen der einzelnen Bytes einer UTF-8-Zeichenkette
<?php
declare(encoding='UTF-8');
$str = "🐘";
for ( $pos=0; $pos < strlen($str); $pos ++ ) {
$byte = substr($str, $pos);
echo 'Byte ' . $pos . ' von $str hat den Wert ' . ord($byte) . PHP_EOL;
}
?>
Das oben gezeigte Beispiel erzeugt folgende Ausgabe:
Byte 0 von $str hat den Wert 240
Byte 1 von $str hat den Wert 159
Byte 2 von $str hat den Wert 144
Byte 3 von $str hat den Wert 152
Siehe auch
- chr() - Erzeugt eine Ein-Byte-Zeichenkette aus einer Zahl
- Eine » ASCII-Tabelle
- mb_ord() - Get Unicode code point of character
- IntlChar::ord() - Return Unicode code point value of character
add a note
User Contributed Notes 4 notes
arglanir+phpnet at gmail dot com ¶
11 years ago
rowan dot collins at cwtdigital dot com ¶
10 years ago
Regarding character sets, and whether or not this is "ASCII". Firstly, there is no such thing as "8-bit ASCII", so if it were ASCII it would only ever return integers up to 127. 8-bit ASCII-compatible encodings include the ISO 8859 family of encodings, which map various common characters to the values from 128 to 255. UTF-8 is also designed so that characters representable in 7-bit ASCII are coded the same; byte values higher than 127 in a UTF-8 string represent the beginning of a multi-byte character.
In fact, like most of PHP's string functions, this function isn't doing anything to do with character encoding at all - it is just interpreting a binary byte from a string as an unsigned integer. That is, ord(chr(200)) will always return 200, but what character chr(200) *means* will vary depending on what character encoding it is *interpreted* as part of (e.g. during display).
A technically correct description would be "Returns an integer representation of the first byte of a string, from 0 to 255. For single-byte encodings such as (7-bit) ASCII and the ISO 8859 family, this will correspond to the first character, and will be the position of that character in the encoding's mapping table. For multi-byte encodings, such as UTF-8 or UTF-16, the byte may not represent a complete character."
The link to asciitable.com should also be replaced by one which explains what character encoding it is displaying, as "Extended ASCII" is an ambiguous and misleading name.
v0rbiz at yahoo dot com ¶
19 years ago
I did not found a unicode/multibyte capable 'ord' function, so...
<?php
function uniord($u) {
$k = mb_convert_encoding($u, 'UCS-2LE', 'UTF-8');
$k1 = ord(substr($k, 0, 1));
$k2 = ord(substr($k, 1, 1));
return $k2 * 256 + $k1;
}
?>
paco at olecode dot com ¶
4 years ago
this function convert UTF-8 string to RTF code string. I am using code of v0rbiz at yahoo dot com, thanks!!!
function cadena_rtf($txt)
{
$result = null;
for ($pos = 0; $pos < mb_strlen($txt); $pos++) {
$char = mb_substr($txt, $pos, 1);
if (!preg_match("/[A-Za-z1-9,.]/", $char)) {
//unicode ord real!!!
$k = mb_convert_encoding($char, 'UCS-2LE', 'UTF-8');
$k1 = ord(substr($k, 0, 1));
$k2 = ord(substr($k, 1, 1));
$ord = $k2 * 256 + $k1;
if ($ord > 255) {
$result .= '\uc1\u' . $ord . '*';
} elseif ($ord > 32768) {
$result .= '\uc1\u' . ($ord - 65535) . '*';
} else {
$result .= "\\'" . dechex($ord);
}
} else {
$result .= $char;
}
}
return $result;
}
