ord

(PHP 4, PHP 5)

ord — 返回字符的 ASCII 码值

说明

int ord ( string $string )

返回字符串 string 第一个字符的 ASCII 码值。

该函数是 chr() 的互补函数。

参数

string: 一个字符。

返回值

返回整型的 ASCII 码值。

范例

Example #1 ord() 范例

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

参见

chr() - 返回指定的字符
» ASCII 码表

用户评论:

[#1] rowan dot collins at cwtdigital dot com [2013-06-11 18:28:54]

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.

[#2] arglanir+phpnet at gmail dot com [2012-08-23 15:06:08]

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 = "abc??????abc"; $offset = 0; while ($offset >= 0) { echo $offset.": ".ordutf8($text, $offset)."\n"; } ?>
Feel free to adapt my code to fit your needs.

[#3] marc at kryn dot org [2012-08-14 12:56:13]

Since this function is not utf-8/unicode ready, you can use following code to get the hex or dec representation of a character.

<?php mb_internal_encoding("UTF-8"); $string = '?J?'; $char = mb_substr($string, 0, 1); var_dump(bin2hex($char)); //hex var_dump(hexdec(bin2hex($char))); //decimal ?>

returns:

string(6) "e28697"
int(14845591)

[#4] xB1N4RYx [2012-06-28 00:49:49]

return the chars as a sql char() string

<?php function AsciiToInt($char){ $success = ""; if(strlen($char) == 1) return "char(".ord($char).")"; else{ for($i = 0; $i < strlen($char); $i++){ if($i == strlen($char) - 1) $success = $success.ord($char[$i]); else $success = $success.ord($char[$i]).","; } return "char(".$success.")"; } } echo AsciiToInt("<br>");//outputs char(60,98,114,62) ?>

[#5] znaeff at mail dot ru [2011-10-05 21:36:52]

I've found that variant with
unpack('N', mb_convert_encoding($c, 'UCS-4BE', 'UTF-8'));
is VERY-VERY slow.
Remember this when process strings longer than 1K.

[#6] Anonymous [2011-04-05 05:49:09]

i need put utf8 hungarian "abc" into html id attribute, but id not contain non-ascii chars (like ??, ?, ?), and not to begin a number.

<?php function utfCharToNumber($char) { $i = 0; $number = ''; while (isset($char{$i})) { $number.= ord($char{$i}); ++$i; } return $number; } // example use foreach (array('a','A','b','B','c','C','e','??','?', '??','?','?','?','?','?','??') as $d) { echo $d,': ',utfCharToNumber($d),"\n"; } ?>

output:
a: 97
A: 65
b: 98
B: 66
c: 99
C: 67
e: 101
??: 195169
?: 195137
??: 195179
?: 195147
?: 195182
?: 195150
?: 197145
?: 197144
??: 195186

i generated the folowing ids:
"char-97", "char-65", "char-98" ...

[#7] darien at etelos dot com [2007-01-19 11:27:03]

I found I wanted to sanitize a string for certain ASCII/ANSI characters, but to leave unicode alone. Since ord() breaks on processing unicode, I drew these two functions up to help with a saniziter which looked at ordinal values. (Finding "pack" and "unpack" was much better than my own powers-of-256 code.)

<?php function ords_to_unistr($ords, $encoding = 'UTF-8'){ // Turns an array of ordinal values into a string of unicode characters $str = ''; for($i = 0; $i < sizeof($ords); $i++){ // Pack this number into a 4-byte string // (Or multiple one-byte strings, depending on context.) $v = $ords[$i]; $str .= pack("N",$v); } $str = mb_convert_encoding($str,$encoding,"UCS-4BE"); return($str); } function unistr_to_ords($str, $encoding = 'UTF-8'){ // Turns a string of unicode characters into an array of ordinal values, // Even if some of those characters are multibyte. $str = mb_convert_encoding($str,"UCS-4BE",$encoding); $ords = array(); // Visit each unicode character for($i = 0; $i < mb_strlen($str,"UCS-4BE"); $i++){ // Now we have 4 bytes. Find their total // numeric value. $s2 = mb_substr($str,$i,1,"UCS-4BE"); $val = unpack("N",$s2); $ords[] = $val[1]; } return($ords); } ?>

[#8] S.N.O.W.M.A.N.-X [2006-09-28 12:47:09]

Well, i was thinking about a method to hash a string with md5 in a loose way, so md5("HELLO") isn't the same like md5("Hello"), even, i my case, it is about cd-titles i got submitted by users. So i made some function transforming my string to right what i want

Thisone is the "call" function returning the "loose hash".
It will get only the chars of a string, make them to uppercase and then hash with md5.

<?php function loosehash($string){ return md5(strtoupper(onlyChars($string))); } ?>

Thisone is moving through a string like a chararray and check for the asciivalues, you can edit the values and condition to fit your needs

<?php function onlyChars($string){ $strlength = strlen($string); $retString = ""; for($i = 0; $i < $strlength; $i++){ if((ord($string[$i]) >= 48 && ord($string[$i]) <= 57) || (ord($string[$i]) >= 65 && ord($string[$i]) <= 90) || (ord($string[$i]) >= 97 && ord($string[$i]) <= 122)){ $retString .= $string[$i]; } } echo $retString; } ?>

[#9] Matthew Flint [2005-10-31 02:59:43]

I wrote the following function to clean illegal characters from input strings.

(Background: I have a php-based news website. People were writing articles in MS Word, then copy-and-pasting the text into the website. Word uses non-standard characters for opening and closing quotes and double-quotes, and for "..." - and this was resulting in articles on the website that failed XHTML validation)

<?php function clean_string_input($input) { $interim = strip_tags($input); if(get_magic_quotes_gpc()) { $interim=stripslashes($interim); } // now check for pure ASCII input // special characters that might appear here: // 96: opening single quote (not strictly illegal, but substitute anyway) // 145: opening single quote // 146: closing single quote // 147: opening double quote // 148: closing double quote // 133: ellipsis (...) // 163: pound sign (this is safe, so no substitution required) // these can be substituted for safe equivalents $result = ''; for ($i=0; $i<strlen($interim); $i++) { $char = $interim{$i}; $asciivalue = ord($char); if ($asciivalue == 96) { $result .= '\\''; } else if (($asciivalue > 31 && $asciivalue < 127) || ($asciivalue == 163) || // pound sign ($asciivalue == 10) || // lf ($asciivalue == 13)) // cr { // it's already safe ASCII $result .= $char; } else if ($asciivalue == 145) // opening single quote { $result .= '\\''; } else if ($asciivalue == 146) // closing single quote { $result .= '\\''; } else if ($asciivalue == 147) // opening double quote { $result .= '"'; } else if ($asciivalue == 148) // closing double quote { $result .= '"'; } else if ($asciivalue == 133) // ellipsis { $result .= '...'; } } return $result; } ?>

[#10] v0rbiz at yahoo dot com [2004-05-28 16:15:59]

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; } ?>