ord

(PHP 4, PHP 5, PHP 7, PHP 8)

ord — Convert the first byte of a string to a value between 0 and 255

Description

ord(string $character): int

Interprets the binary value of the first byte of character as an unsigned integer between 0 and 255.

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.

This function complements chr().

Parameters

character: A character.

Return Values

An integer between 0 and 255.

Examples

Example #1 ord() example

<?php
$str = "\n";
if (ord($str) == 10) {
    echo "The first character of \$str is a line feed.\n";
}
?>

Example #2 Examining the individual bytes of a UTF-8 string

<?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;
}
?>

The above example will output:

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

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User Contributed Notes 6 notes

down

arglanir+phpnet at gmail dot com ¶

12 years ago

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 = "abcàêß€abc";
$offset = 0;
while ($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.

down

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;
   }

down

rowan dot collins at cwtdigital dot com ¶

11 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.

down

v0rbiz at yahoo dot com ¶

20 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;

}

?>

down

-1

Noname ¶

2 years ago

<?php

declare (encoding='UTF-8');

$animalsstr = '🐀🐁🐂🐃🐄🐅🐆🐇🐈🐉🐊🐋🐌🐍🐎🐏🐐🐑🐒🐓🐔🐕🐖🐗🐘🐙'
        . '🐚🐛🐜🐝🐞🐟🐠🐡🐢🐣🐤🐥🐦🐧🐨🐩🐪🐫🐬🐭🐮🐯🐰🐱🐲🐳🐴🐵'
        . '🐶🐷🐸🐹🐺🐻🐼🐽🐾🐿';

$animals = mb_str_split($animalsstr);
foreach ($animals as $animal) {
    for ($pos = 0; $pos < strlen($animal); $pos++) {
        $byte = substr($animal, $pos);
        echo "Byte $pos of $animal has value " . ord($byte) . PHP_EOL;
    }
}

?>

down

-3

Anonymous ¶

3 years ago

For anyone who's looking to convert full strings to map and back it's pretty simple but takes some getting used to...the code below saves an hour of scrounging codes for beginners like myself.

function var2map($a) {
    $b='';
    $c=strlen($a);
    for($i=0; $i<$c; ++$i) {
        $d=ord(substr($a,$i,1));
        if($d<10) {
            $e='00'.$d;
        } else {
            if($d<100) {
                $e='0'.$d;
            } else {
                $e=$d;
            }
        }
        if($b=='') {
            $b=$e;
        } else {
            $b=$b.$e;
        }
    }
    return $b;
}

function map2var($a) {
    $b='';
    $c=strlen($a) / 3;
    for($i=0; $i<$c; ++$i) {
        $d=chr(substr($a,$i*3,3));
        if($b=='') {
            $b=$d;
        } else {
            $b=$b.$d;
        }
    }
    return $b;
}

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ord

Description

Parameters

Return Values

Examples

See Also

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User Contributed Notes 6 notes