For getting a substring of UTF-8 characters, I highly recommend mb_substr
<?php
$utf8string = "cakeæøå";
echo substr($utf8string,0,5);
// output cake#
echo mb_substr($utf8string,0,5,'UTF-8');
//output cakeæ
?>
substr
(PHP 4, PHP 5, PHP 7, PHP 8)
substr — 文字列の一部分を返す
説明
substr
( string
$string
, int $offset
, int|null $length = null
) : string
文字列 string の、offset
で指定された位置から length バイト分の文字列を返します。
パラメータ
-
string -
入力文字列。
-
offset -
offsetが正の場合、返される文字列は、stringの 0 から数えてoffset番目から始まる文字列となります。 例えば、文字列'abcdef'において位置0にある文字は、'a'であり、 位置2には'c'があります。offsetが負の場合、返される文字列は、stringの後ろから数えてoffset番目から始まる文字列となります。stringの長さがoffset文字より短い場合はfalseが返されます。例1 負の
offsetの使用<?php
$rest = substr("abcdef", -1); // "f" を返す
$rest = substr("abcdef", -2); // "ef" を返す
$rest = substr("abcdef", -3, 1); // "d" を返す
?> -
length -
lengthが指定され、かつ正である場合、 返される文字列はoffset(stringの長さに依存します) から数えてlength文字数分となります。lengthが指定され、かつ負である場合、stringの終端からその文字数分の文字が省略されます (offsetが負の場合は、 開始位置を算出したあとで)。 もしoffsetが切り出し位置を超える場合、falseが返されます。lengthが指定され、かつ0、null、もしくはfalseであれば、空の文字が返されます。lengthを省略した場合は、offsetの位置から文字列の最後までの部分文字列を返します。例2 負の
lengthの使用<?php
$rest = substr("abcdef", 0, -1); // "abcde" を返す
$rest = substr("abcdef", 2, -1); // "cde" を返す
$rest = substr("abcdef", 4, -4); // false を返す
$rest = substr("abcdef", -3, -1); // "de" を返す
?>
返り値
string の一部を返します。失敗した場合に false を返します。あるいは空文字列を返します。
変更履歴
| バージョン | 説明 |
|---|---|
| 8.0.0 |
length は、nullable になりました。
|
| 8.0.0 |
この関数は、前のバージョンで false を返す場合に、空文字列を返すようになりました。
|
例
例3 基本的な substr() の使用法
<?php
echo substr('abcdef', 1); // bcdef
echo substr('abcdef', 1, 3); // bcd
echo substr('abcdef', 0, 4); // abcd
echo substr('abcdef', 0, 8); // abcdef
echo substr('abcdef', -1, 1); // f
// 文字列中の 1 文字にアクセスすることも
// "角括弧" を使用することで可能
$string = 'abcdef';
echo $string[0]; // a
echo $string[3]; // d
echo $string[strlen($string)-1]; // f
?>
例4 substr() でのキャストの挙動
<?php
class apple {
public function __toString() {
return "green";
}
}
echo "1) ".var_export(substr("pear", 0, 2), true).PHP_EOL;
echo "2) ".var_export(substr(54321, 0, 2), true).PHP_EOL;
echo "3) ".var_export(substr(new apple(), 0, 2), true).PHP_EOL;
echo "4) ".var_export(substr(true, 0, 1), true).PHP_EOL;
echo "5) ".var_export(substr(false, 0, 1), true).PHP_EOL;
echo "6) ".var_export(substr("", 0, 1), true).PHP_EOL;
echo "7) ".var_export(substr(1.2e3, 0, 4), true).PHP_EOL;
?>
上の例の PHP 7 での出力は、このようになります。
1) 'pe' 2) '54' 3) 'gr' 4) '1' 5) '' 6) '' 7) '1200'
上の例の PHP 5 での出力は、このようになります。
1) 'pe' 2) '54' 3) 'gr' 4) '1' 5) false 6) false 7) '1200'
エラー / 例外
エラー時に false を返します。
<?php
var_dump(substr('a', 2)); // bool(false)
?>
参考
- strrchr() - 文字列中に文字が最後に現れる場所を取得する
- substr_replace() - 文字列の一部を置換する
- preg_match() - 正規表現によるマッチングを行う
- trim() - 文字列の先頭および末尾にあるホワイトスペースを取り除く
- mb_substr() - 文字列の一部を得る
- wordwrap() - 指定した文字数で文字列を分割する
- 文字列への文字単位のアクセスと修正
add a note
User Contributed Notes 49 notes
Andreas Bur (andreas dot buro at gmail dot com) ¶
11 years ago
biohazard dot ge at gmail dot com ¶
7 years ago
may be by following functions will be easier to extract the needed sub parts from a string:
<?php
after ('@', 'biohazard@online.ge');
//returns 'online.ge'
//from the first occurrence of '@'
before ('@', 'biohazard@online.ge');
//returns 'biohazard'
//from the first occurrence of '@'
between ('@', '.', 'biohazard@online.ge');
//returns 'online'
//from the first occurrence of '@'
after_last ('[', 'sin[90]*cos[180]');
//returns '180]'
//from the last occurrence of '['
before_last ('[', 'sin[90]*cos[180]');
//returns 'sin[90]*cos['
//from the last occurrence of '['
between_last ('[', ']', 'sin[90]*cos[180]');
//returns '180'
//from the last occurrence of '['
?>
here comes the source:
<?php
function after ($this, $inthat)
{
if (!is_bool(strpos($inthat, $this)))
return substr($inthat, strpos($inthat,$this)+strlen($this));
};
function after_last ($this, $inthat)
{
if (!is_bool(strrevpos($inthat, $this)))
return substr($inthat, strrevpos($inthat, $this)+strlen($this));
};
function before ($this, $inthat)
{
return substr($inthat, 0, strpos($inthat, $this));
};
function before_last ($this, $inthat)
{
return substr($inthat, 0, strrevpos($inthat, $this));
};
function between ($this, $that, $inthat)
{
return before ($that, after($this, $inthat));
};
function between_last ($this, $that, $inthat)
{
return after_last($this, before_last($that, $inthat));
};
// use strrevpos function in case your php version does not include it
function strrevpos($instr, $needle)
{
$rev_pos = strpos (strrev($instr), strrev($needle));
if ($rev_pos===false) return false;
else return strlen($instr) - $rev_pos - strlen($needle);
};
?>
pugazhenthi k ¶
8 years ago
<?Php
### SUB STRING BY WORD USING substr() and strpos() #####
### THIS SCRIPT WILL RETURN PART OF STRING WITHOUT WORD BREAK ###
$description = ‘your description here your description here your description here your description here your description here your description here your description hereyour description here your description here’ // your description here .
$no_letter = 30 ;
if(strlen($desctiption) > 30 )
{
echo substr($description,0,strpos($description,’ ‘,30)); //strpos to find ‘ ‘ after 30 characters.
}
else {
echo $description;
}
?>
link ¶
11 years ago
I created some functions for entity-safe splitting+lengthcounting:
<?php
function strlen_entities($text)
{
preg_match_all(
'/((?:&(?:#[0-9]{2,}|[a-z]{2,});)|(?:[^&])|'.
'(?:&(?!\w;)))s',$text,$textarray);
return count($textarray[0]);
}
function substr_entities($text,$start,$limit=0)
{
$return = '';
preg_match_all(
'/((?:&(?:#[0-9]{2,}|[a-z]{2,});)|(?:[^&])|'.
'(?:&(?!\w;)))s',$text,$textarray);
$textarray = $textarray[0];
$numchars = count($textarray)-1;
if ($start>=$numchars)
return false;
if ($start<0)
{
$start = ($numchars)+$start+1;
}
if ($start>=0)
{
if ($limit==0)
{
$end=$numchars;
}
elseif ($limit>0)
{
$end = $start+($limit-1);
}
else
{
$end = ($numchars)+$limit;
}
for ($i=$start;$i<=$end;$i++)
{
$return .= $textarray[$i];
}
return $return;
}
}
?>
greg at apparel dot com ¶
7 years ago
Coming to PHP from classic ASP I am used to the Left() and Right() functions built into ASP so I did a quick PHPversion. hope these help someone else making the switch
function left($str, $length) {
return substr($str, 0, $length);
}
function right($str, $length) {
return substr($str, -$length);
}
mar dot czapla at gmail dot com ¶
12 years ago
Here we have gr8 function which simply convert ip address to a number using substr with negative offset.
You can need it if you want to compare some IP addresses converted to a numbers.
For example when using ip2country, or eliminating same range of ip addresses from your website :D
<?php
function ip2no($val)
{
list($A,$B,$C,$D) = explode(".",$val);
return
substr("000".$A,-3).
substr("000".$B,-3).
substr("000".$C,-3).
substr("000".$D,-3);
}
$min = ip2no("10.11.1.0");
$max = ip2no("111.11.1.0");
$visitor = ip2no("105.1.20.200");
if($min<$visitor && $visitor<$max)
{ echo 'Welcome !'; }
else
{ echo 'Get out of here !'; }
?>
webmaster at oehoeboeroe dot nl ¶
11 years ago
You might expect substr('123456', 6) to return an empty string. Instead it returns boolean FALSE.
This behavior should be mentioned in the Return Values section of the manual. Instead it is only mentioned in the Parameters section.
If you need an empty string instead of a boolean FALSE you should typecast the result to a string.
<?php
$a = substr('123456', 6); // equivalent to $a = FALSE
$a = (string) substr('123456', 6); // equivalent to $a = '';
?>
woutermb at gmail dot com ¶
15 years ago
Well this is a script I wrote, what it does is chop up long words with malicious meaning into several parts. This way, a chat in a table will not get stretched anymore.
<?php
function text($string,$limit=20,$chop=10){
$text = explode(" ",$string);
while(list($key, $value) = each($text)){
$length = strlen($value);
if($length >=20){
for($i=0;$i<=$length;$i+=10){
$new .= substr($value, $i, 10);
$new .= " ";
}
$post .= $new;
}
elseif($length <=15){
$post .= $value;
}
$post .= " ";
}
return($post);
}
// for example, this would return:
$output = text("Well this text doesn't get cut up, yet thisssssssssssssssssssssssss one does.", 10, 5);
echo($output); // "Well this text doesn't get cup up, yet thiss sssss sssss sssss sssss sss one does."
?>
I hope it was useful.. :)
fanfatal at fanfatal dot pl ¶
15 years ago
Hmm ... this is a script I wrote, whitch is very similar to substr, but it isn't takes html and bbcode for counting and it takes portion of string and show avoided (html & bbcode) tags too ;]
Specially usefull for show part of serach result included html and bbcode tags
<?php
/**
* string csubstr ( string string, int start [, int length] )
*
* @author FanFataL
* @param string string
* @param int start
* @param [int length]
* @return string
*/
function csubstr($string, $start, $length=false) {
$pattern = '/(\[\w+[^\]]*?\]|\[\/\w+\]|<\w+[^>]*?>|<\/\w+>)/i';
$clean = preg_replace($pattern, chr(1), $string);
if(!$length)
$str = substr($clean, $start);
else {
$str = substr($clean, $start, $length);
$str = substr($clean, $start, $length + substr_count($str, chr(1)));
}
$pattern = str_replace(chr(1),'(.*?)',preg_quote($str));
if(preg_match('/'.$pattern.'/is', $string, $matched))
return $matched[0];
return $string;
}
?>
Using this is similar to simple substr.
Greatings ;]
...
leon weidauer ¶
9 years ago
When using a value of a wrong type as second parameter , substr() does not return FALSE but NULL although the docs say, it should return FALSE on error.
Prior to PHP 5.3, substr() tries to cast the second parameter to int and doesn't throw any errors. Since PHP 5.3 a warning is thrown.
slow at acedsl dot com ¶
9 years ago
Anyone coming from the Python world will be accustomed to making substrings by using a "slice index" on a string. The following function emulates basic Python string slice behavior. (A more elaborate version could be made to support array input as well as string, and the optional third "step" argument.)
<?php
function py_slice($input, $slice) {
$arg = explode(':', $slice);
$start = intval($arg[0]);
if ($start < 0) {
$start += strlen($input);
}
if (count($arg) === 1) {
return substr($input, $start, 1);
}
if (trim($arg[1]) === '') {
return substr($input, $start);
}
$end = intval($arg[1]);
if ($end < 0) {
$end += strlen($input);
}
return substr($input, $start, $end - $start);
}
print py_slice('abcdefg', '2') . "\n";
print py_slice('abcdefg', '2:4') . "\n";
print py_slice('abcdefg', '2:') . "\n";
print py_slice('abcdefg', ':4') . "\n";
print py_slice('abcdefg', ':-3') . "\n";
print py_slice('abcdefg', '-3:') . "\n";
?>
The $slice parameter can be a single character index, or a range separated by a colon. The start of the range is inclusive and the end is exclusive, which may be counterintuitive. (Eg, py_slice('abcdefg', '2:4') yields 'cd' not 'cde'). A negative range value means to count from the end of the string instead of the beginning. Both the start and end of the range may be omitted; the start defaults to 0 and the end defaults to the total length of the input.
The output from the examples:
c
cd
cdefg
abcd
abcd
efg
Petez ¶
13 years ago
I wanted to work out the fastest way to get the first few characters from a string, so I ran the following experiment to compare substr, direct string access and strstr:
<?php
/* substr access */
beginTimer();
for ($i = 0; $i < 1500000; $i++){
$opening = substr($string,0,11);
if ($opening == 'Lorem ipsum'){
true;
}else{
false;
}
}
$endtime1 = endTimer();
/* direct access */
beginTimer();
for ($i = 0; $i < 1500000; $i++){
if ($string[0] == 'L' && $string[1] == 'o' && $string[2] == 'r' && $string[3] == 'e' && $string[4] == 'm' && $string[5] == ' ' && $string[6] == 'i' && $string[7] == 'p' && $string[8] == 's' && $string[9] == 'u' && $string[10] == 'm'){
true;
}else{
false;
}
}
$endtime2 = endTimer();
/* strstr access */
beginTimer();
for ($i = 0; $i < 1500000; $i++){
$opening = strstr($string,'Lorem ipsum');
if ($opening == true){
true;
}else{
false;
}
}
$endtime3 = endTimer();
echo $endtime1."\r\n".$endtime2."\r\n".$endtime3;
?>
The string was 6 paragraphs of Lorem Ipsum, and I was trying match the first two words. The experiment was run 3 times and averaged. The results were:
(substr) 3.24
(direct access) 11.49
(strstr) 4.96
(With standard deviations 0.01, 0.02 and 0.04)
THEREFORE substr is the fastest of the three methods for getting the first few letters of a string.
Bradley from California ¶
15 years ago
Add on to (a function originally written by) "Matias from Argentina": str_format_number function.
Just added handling of $String shorter then $Format by adding a side to start the fill and a string length to the while loop.
<?php
function str_format_number($String, $Format, $Start = 'left'){
//If we want to fill from right to left incase string is shorter then format
if ($Start == 'right') {
$String = strrev($String);
$Format = strrev($Format);
}
if($Format == '') return $String;
if($String == '') return $String;
$Result = '';
$FormatPos = 0;
$StringPos = 0;
while ((strlen($Format) - 1) >= $FormatPos && strlen($String) > $StringPos) {
//If its a number => stores it
if (is_numeric(substr($Format, $FormatPos, 1))) {
$Result .= substr($String, $StringPos, 1);
$StringPos++;
//If it is not a number => stores the caracter
} else {
$Result .= substr($Format, $FormatPos, 1);
}
//Next caracter at the mask.
$FormatPos++;
}
if ($Start == 'right') $Result = strrev($Result);
return $Result;
}
?>
post [at] jannik - zappe [dot] de ¶
12 years ago
Just a little function to cut a string by the wanted amount. Works in both directions.
<?php
function cutString($str, $amount = 1, $dir = "right")
{
if(($n = strlen($str)) > 0)
{
if($dir == "right")
{
$start = 0;
$end = $n-$amount;
} elseif( $dir == "left") {
$start = $amount;
$end = $n;
}
return substr($str, $start, $end);
} else return false;
}
?>
Enjoy ;)
php at richardneill dot org ¶
6 years ago
Frequently we want to check whether one string ends with (or starts with) another. These may be useful:
function str_ends($string,$end){
return (substr($string,-strlen($end),strlen($end)) === $end);
}
function str_begins($string,$start){
return (substr($string,0,strlen($start)) === $start);
}
Example:
if (str_ends ($filename, ".jpg")){
echo "The extension is .jpg";
}
steve at unicycle dot co dot nz ¶
15 years ago
To quickly trim an optional trailing slash off the end of a path name:
if (substr( $path, -1 ) == '/') $path = substr( $path, 0, -1 );
nikolai dot wuestemann at t-online dot de ¶
10 years ago
If you want to have a string BETWEEN two strings, just use this function:
<?php
function get_between($input, $start, $end)
{
$substr = substr($input, strlen($start)+strpos($input, $start), (strlen($input) - strpos($input, $end))*(-1));
return $substr;
}
//Example:
$string = "123456789";
$a = "12";
$b = "9";
echo get_between($string, $a, $b);
//Output:
//345678
?>
fatihmertdogancan at hotmail dot com ¶
7 years ago
[English]
I created python similar accesing list or string with php substr & strrev functions.
Use: str($string,$pattern)
About the python pattern,
http://docs.python.org/release/1.5.1p1/tut/strings.html
http://effbot.org/zone/python-list.htm
About of pattern structures
[start:stop:step]
Example,
<?php
$s = "fatihmertdogancan";
echo str($s,"1:9:-2");
echo "<br/>";
echo str($s,"1:-3:-2");
echo "<br/>";
echo str($s,"1:-11:-5");
echo "<br/>";
echo str($s,"1:9:4");
?>
Output,
thetoacn
eht
aom
htan
This is function phpfiddle link: http://phpfiddle.org/main/code/e82-y5d
or source;
<?php
function str($str,$pattern){
//[start:stop:step]
//pattern -> ([-]?[0-9]*|\s):([-]?[0-9]*|\s):([-]?[0-9]*|\s)
preg_match("/([-]?[0-9]*|\s?):([-]?[0-9]*|\s?):?([-]?[0-9]*|\s?)/", $pattern, $yakala);
$start = $yakala[1];
$stop = $yakala[2];
$step = $yakala[3];
if(empty($start) && empty($stop) && $step == "-1"){//istisna durum
return strrev($str);
}else if(empty($start) && empty($stop) && isset($step)){//istisna durum
$rev = "";
$yeni = "";
if($step[0] == "-" && $stop != "-1"){$rev = "VAR";}
$atla = abs($step);
for($i = 0; $i <= strlen($str); $i++){
$offset = $i*$atla;
if(isset($str[$offset])){
$yeni = $yeni.$str[$offset];
}
}
if($rev != "VAR"){
return substr($yeni,0,strlen($str)-1);
//"hepsi boş, step dolu o da +";
}else{
return strrev(substr($yeni,0,strlen($str)-1));
//"hepsi boş, step dolu o da -";
}
}
if(empty($start) && empty($stop) && empty($step)){
return $str;
//"hepsi boş";
}else if(empty($start)){
if(isset($stop) && empty($step)){
$rev = "";
if($stop[0] == "-"){$rev = "VAR";}
if($rev != "VAR"){
return substr($str,0,$stop);
//"start ve step boş, stop dolu"
}else{
return strrev(substr($str,0,$stop));
//"start ve step boş, stop -1";
}
}else if(isset($stop) && isset($step)){
$rev = "";
if($stop[0] == "-"){$rev = "VAR";}
$yeni = "";
if($step == 1){
if($rev != "VAR"){
return $str;
//"start boş, stop ve step dolu, step 1";
}else{
return strrev(substr($str,0,abs($stop))); //abs -> mutlak değer (-5 = 5)
//"start boş, stop -, step dolu, step 1";
}
}else{
$atla = abs($step);
for($i = 0; $i <= strlen($str); $i++){
$offset = $i*$atla;
if(isset($str[$offset])){
$yeni = $yeni.$str[$offset];
}
}
if($rev != "VAR"){
return substr($yeni,0,$stop);
//"start boş, step ve stop dolu";
}else{
return strrev(substr($yeni,0,abs($stop)));
//"start boş, step ve stop -";
}
}
}
//start boş değilse
}else if(!empty($start)){
if(isset($stop) && empty($step)){
$rev = "";
if($stop[0] == "-"){$rev = "VAR";}
if($rev != "VAR"){
return substr($str,$start,$stop);
//return "step boş, start ve stop dolu";
}else{
return strrev(substr($str,0,abs($stop)));
//"step boş, start ve stop dolu, stop -";
}
}else if(isset($stop) && isset($step)){
//hepsi dolu
$rev = "";
if($stop[0] == "-"){$rev = "VAR";}
$yeni = "";
if($step == 1){
if($rev != "VAR"){
return substr($str,$start,$stop);
//"hepsi dolu, step 1";
}else{
return substr($str,$start,abs($stop));
//"hepsi dolu, step 1, stop -";
}
}else{
if($stop[0] == "-"){$rev = "VAR";}
$atla = abs($step);
for($i = 0; $i <= strlen($str); $i++){
$offset = $i*$atla;
if(isset($str[$offset])){
$yeni = $yeni.$str[$offset];
}
}
if($rev != "VAR"){
return substr($yeni,$start,$stop);
//"hepsi dolu";
}else{
return strrev(substr($yeni,$start,abs($stop)));
//"hepsi dolu, stop -";
}
}
}
}
}
?>
Good works..
frank at jkelloggs dot dk ¶
15 years ago
Regarding the utf8_substr function from lmak: The pattern '/./u' doesn't match newline characters. This means that the substring from 0 to the total length of the string will miss the number of characters in the end matching the number of newlines in the string. To fix this one can add the s modifier (PCRE_DOTALL) in the pattern:
<?php
function utf8_substr($str,$start)
{
preg_match_all("/./su", $str, $ar);
if(func_num_args() >= 3) {
$end = func_get_arg(2);
return join("",array_slice($ar[0],$start,$end));
} else {
return join("",array_slice($ar[0],$start));
}
}
?>
egingell at sisna dot com ¶
14 years ago
<?php
/**
* string substrpos(string $str, mixed $start [[, mixed $end], boolean $ignore_case])
*
* If $start is a string, substrpos will return the string from the position of the first occuring $start to $end
*
* If $end is a string, substrpos will return the string from $start to the position of the first occuring $end
*
* If the first character in (string) $start or (string) $end is '-', the last occuring string will be used.
*
* If $ignore_case is true, substrpos will not care about the case.
* If $ignore_case is false (or anything that is not (boolean) true, the function will be case sensitive.
* Both of the above: only applies if either $start or $end are strings.
*
* echo substrpos('This is a string with 0123456789 numbers in it.', 5, '5');
* // Prints 'is a string with 01234';
*
* echo substrpos('This is a string with 0123456789 numbers in it.', '5', 5);
* // Prints '56789'
*
* echo substrpos('This is a string with 0123456789 numbers in it and two strings.', -60, '-string')
* // Prints 's is a string with 0123456789 numbers in it and two '
*
* echo substrpos('This is a string with 0123456789 numbers in it and two strings.', -60, '-STRING', true)
* // Prints 's is a string with 0123456789 numbers in it and two '
*
* echo substrpos('This is a string with 0123456789 numbers in it and two strings.', -60, '-STRING', false)
* // Prints 's is a string with 0123456789 numbers in it and two strings.'
*
* Warnings:
* Since $start and $end both take either a string or an integer:
* If the character or string you are searching $str for is a number, pass it as a quoted string.
* If $end is (integer) 0, an empty string will be returned.
* Since this function takes negative strings ('-search_string'):
* If the string your using in $start or $end is a '-' or begins with a '-' escape it with a '\'.
* This only applies to the *first* character of $start or $end.
*/
// Define stripos() if not defined (PHP < 5).
if (!is_callable("stripos")) {
function stripos($str, $needle, $offset = 0) {
return strpos(strtolower($str), strtolower($needle), $offset);
}
}
function substrpos($str, $start, $end = false, $ignore_case = false) {
// Use variable functions
if ($ignore_case === true) {
$strpos = 'stripos'; // stripos() is included above in case it's not defined (PHP < 5).
} else {
$strpos = 'strpos';
}
// If end is false, set it to the length of $str
if ($end === false) {
$end = strlen($str);
}
// If $start is a string do what's needed to make it an integer position for substr().
if (is_string($start)) {
// If $start begins with '-' start processing until there's no more matches and use the last one found.
if ($start{0} == '-') {
// Strip off the '-'
$start = substr($start, 1);
$found = false;
$pos = 0;
while(($curr_pos = $strpos($str, $start, $pos)) !== false) {
$found = true;
$pos = $curr_pos + 1;
}
if ($found === false) {
$pos = false;
} else {
$pos -= 1;
}
} else {
// If $start begins with '\-', strip off the '\'.
if ($start{0} . $start{1} == '\-') {
$start = substr($start, 1);
}
$pos = $strpos($str, $start);
}
$start = $pos !== false ? $pos : 0;
}
// Chop the string from $start to strlen($str).
$str = substr($str, $start);
// If $end is a string, do exactly what was done to $start, above.
if (is_string($end)) {
if ($end{0} == '-') {
$end = substr($end, 1);
$found = false;
$pos = 0;
while(($curr_pos = strpos($str, $end, $pos)) !== false) {
$found = true;
$pos = $curr_pos + 1;
}
if ($found === false) {
$pos = false;
} else {
$pos -= 1;
}
} else {
if ($end{0} . $end{1} == '\-') {
$end = substr($end, 1);
}
$pos = $strpos($str, $end);
}
$end = $pos !== false ? $pos : strlen($str);
}
// Since $str has already been chopped at $start, we can pass 0 as the new $start for substr()
return substr($str, 0, $end);
}
?>
ivanhoe011 at gmail dot com ¶
15 years ago
If you need just a single character from the string you don't need to use substr(), just use curly braces notation:
<?php
// both lines will output the 3rd character
echo substr($my_string, 2, 1);
echo $my_string{2};
?>
curly braces syntax is faster and more readable IMHO..
Anonymous ¶
3 years ago
Be aware of a slight inconsistency between substr and mb_substr
mb_substr("", 4); returns empty string
substr("", 4); returns boolean false
tested in PHP 7.1.11 (Fedora 26) and PHP 5.4.16 (CentOS 7.4)
kleeh at bellsouth dot net ¶
3 years ago
If I may, I'd like to add an example for a bit more clarification on the action of substr(). There's a note saying "If string is equal to start characters long, an empty string will be returned. Prior to this version, FALSE was returned in this case. ".
That description puzzled me until I worked it out. So, if your string is "x" and you do 'substr("x",0, 1)' then you'll get "x" as expected. Same thing for substr("x",0,4)' or any other LENGTH parm. But if the START parm is equal to the LENGTH of the string, then you'll get an empty string (PHP 7) or FALSE (prior to PHP 7). An example of this would be 'substr("x", 1, 1)' , which would return either an empty string or FALSE. Because your "x", which has a LENGTH of '1', is in the 0th position, so 'starting' your substr request at position 1 results in the empty string (or FALSE) because there is nothing after your "x" in this example. Just trying to mitigate some head-scratching over the phrasing of the previous note.
rob NOSPAM at clancentric dot net ¶
15 years ago
I have developed a function with a similar outcome to jay's
Checks if the last character is or isnt a space. (does it the normal way if it is)
It explodes the string into an array of seperate works, the effect is... it chops off anything after and including the last space.
<?php
function limit_string($string, $charlimit)
{
if(substr($string,$charlimit-1,1) != ' ')
{
$string = substr($string,'0',$charlimit);
$array = explode(' ',$string);
array_pop($array);
$new_string = implode(' ',$array);
return $new_string.'...';
}
else
{
return substr($string,'0',$charlimit-1).'...';
}
}
?>
m.m.j.kronenburg ¶
4 years ago
<?php
/**
* Returns and extracts the portion of string specified by the
* start and length parameters from the original string.
*
* This function is simulair to function substr() except that it
* removes the substring from the orignal string
* (passed by reference).
*
* @param string $string The input string.
* @param integer $start The start position (see substr() for
* explanation).
* @param integer $length The length (see substr()
* for explanation).
* @return mixed The substring or FALSE (see substr()
* for explanation).
**/
function substrex(&$string, $start, $length = PHP_INT_MAX)
{
if($start > strlen($string)) { return false; }
if(empty($length)) { return ''; }
if($start < 0) { $start = max(0, $start + strlen($string)); }
$end = ($length < 0) ?
strlen($string) + $length :
min(strlen($string), $start + $length);
if($end < $start) { return false; }
$length = $end - $start;
$substr = substr($string, $start, $length);
$string = substr($string, 0, $start).substr($string, $end);
return $substr;
}
?>
Anonymous ¶
6 years ago
substr() exhibits rather unexpected behavior with respect to when it returns "" and when it returns FALSE. Specifically, the following appears to hold (tested on PHP 5.4.19):
* if $string is "", it always returns FALSE
* if ($start >= 0) and ($start >= strlen($string)) it returns FALSE
* if ($start >= 0) and ($length<($start - strlen($string))) it returns FALSE
* if ($start < 0) then it returns FALSE if *and only if* $length<-strlen($string).
No other cases return FALSE.
Note that in the last case, the position indicated by $start doesn't actually matter!
Also worth noting is that if you supply a $start that is < -strlen($string), it will be treated exactly as if you had set $start = strlen($string).
Here are some test cases to illustrate this behavior:
substr("",0,0) === FALSE
substr("",0,4) === FALSE
substr("",-2,4) === FALSE
substr("abc",3,0) === FALSE
substr("abc",3,10) === FALSE
substr("abc",3,-1) === FALSE
substr("abc",0,-4) === FALSE
substr("abc",2,-2) === FALSE
substr("abc",-1,-4) === FALSE
substr("abc",-4,-4) === FALSE
substr("abc",-5,-4) === FALSE
substr("abc",-10,-5) === FALSE
substr("abc",-10,-2) === "a"
substr("abc",-1,-3) === ""
substr("abc",-1,-2) === ""
substr("abc",-2,-3) === ""
substr("abc",0,0) === ""
substr("abc",-3,0) === ""
substr("abc",-10,0) === ""
substr("abc",-3,4) === "abc"
substr("abc",-10,20) === "abc"
substr("abc",-2,-2) === ""
substr("abc",-2,1) === "b"
substr("abc",0,-3) === ""
substr("abc",2,-1) === ""
Nadeem ¶
6 years ago
Truncate a float number. Similar to the Excel trunc function.
<?php
function truncate_number($val,$decimals=2){
$number=array();
$number=explode(".",$val);
$result=0;
if (count($number)>1){
$result = $number[0] . "." . substr($number[1],0,$decimals);
} else {
$result = $val;
}
unset($number);
return $result;
}
echo truncate_number(99.123456,2); //result = 99.12
echo truncate_number(99.123456,5); //result = 99.12345
echo truncate_number(99.123456,1); //result = 99.1
?>
pheagey at gmail dot com ¶
8 years ago
Using a 0 as the last parameter for substr().
As per examples
<?php $var = substr($var, 4); ?>
works no problem. However
<?php $var = substr($var, 4, 0); ?>
will get you nothing. Just a quick heads up
Quicker ¶
9 years ago
If you need to parse utf-8 strings char by char, try this one:
<?php
$utf8marker=chr(128);
$count=0;
while(isset($string{$count})){
if($string{$count}>=$utf8marker) {
$parsechar=substr($string,$count,2);
$count+=2;
} else {
$parsechar=$string{$count};
$count++;
}
/* do what you like with parsechar ... , eg.:*/ echo $parsechar."<BR>\r\n";
}
?>
- it works without mb_substr
- it is fast, because it grabs characters based on indexes when possible and avoids any count and split functions
Cristianlf ¶
10 years ago
I needed a function like lpad from oracle, or right from SQL
then I use this code :
<?php
function right($string,$chars)
{
$vright = substr($string, strlen($string)-$chars,$chars);
return $vright;
}
echo right('0r0j4152',4);
?>
Result:
4152
------------------------------------------------
This function is really simple, I just wanted to share, maybe helps someone out there.
regards,
vnonov at gmail dot com / Viktor Nonov ¶
11 years ago
<?php
//removes string from the end of other
function removeFromEnd($string, $stringToRemove) {
$stringToRemoveLen = strlen($stringToRemove);
$stringLen = strlen($string);
$pos = $stringLen - $stringToRemoveLen;
$out = substr($string, 0, $pos);
return $out;
}
$string = 'picture.jpg.jpg';
$string = removeFromEnd($string, '.jpg');
?>
gkhelloworld at gmail dot com ¶
11 years ago
Shortens the filename and its expansion has seen.
<?php
$file = "Hellothisfilehasmorethan30charactersandthisfayl.exe";
function funclongwords($file)
{
if (strlen($file) > 30)
{
$vartypesf = strrchr($file,".");
$vartypesf_len = strlen($vartypesf);
$word_l_w = substr($file,0,15);
$word_r_w = substr($file,-15);
$word_r_a = substr($word_r_w,0,-$vartypesf_len);
return $word_l_w."...".$word_r_a.$vartypesf;
}
else
return $file;
}
// RETURN: Hellothisfileha...andthisfayl.exe
?>
kaysar in ymail in com ¶
11 years ago
Drop extensions of a file (even from a file location string)
<?php
$filename = "c:/some dir/abc defg. hi.jklmn";
echo substr($filename, 0, (strlen ($filename)) - (strlen (strrchr($filename,'.'))));
?>
output: c:/some dir/abc defg. hi
Hope it may help somebody like me.. (^_^)
link ¶
11 years ago
And as always there is bound to be a bug:
<?php
function strlen_entities($text)
{
preg_match_all(
'/((?:&(?:#[0-9]{2,}|[a-z]{2,});)|(?:[^&])|'.
'(?:&(?!\w;)))s',$text,$textarray);
return count($textarray[0]);
}
function substr_entities($text,$start,$limit=0)
{
$return = '';
preg_match_all(
'/((?:&(?:#[0-9]{2,}|[a-z]{2,});)|(?:[^&])|'.
'(?:&(?!\w;)))s',$text,$textarray);
$textarray = $textarray[0];
$numchars = count($textarray)-1;
if ($start>=$numchars)
return false;
if ($start<0)
{
$start = ($numchars)+$start+1;
}
if ($start>=0)
{
if ($limit==0)
{
$end=$numchars;
}
elseif ($limit>0)
{
$end = $start+($limit-1);
}
else
{
$end = ($numchars)+$limit;
}
for ($i=$start;($i<=$end && isset($textarray[$i]));$i++)
{
$return .= $textarray[$i];
}
return $return;
}
}
?>
bleakwind at msn dot com ¶
15 years ago
This returns the portion of str specified by the start and length parameters..
It can performs multi-byte safe on number of characters. like mb_strcut() ...
Note:
1.Use it like this bite_str(string str, int start, int length [,byte of on string]);
2.First character's position is 0. Second character position is 1, and so on...
3.$byte is one character length of your encoding, For example: utf-8 is "3", gb2312 and big5 is "2"...you can use the function strlen() get it...
Enjoy it :) ...
--- Bleakwind
QQ:940641
http://www.weaverdream.com
PS:I'm sorry my english is too poor... :(
<?php
// String intercept By Bleakwind
// utf-8:$byte=3 | gb2312:$byte=2 | big5:$byte=2
function bite_str($string, $start, $len, $byte=3)
{
$str = "";
$count = 0;
$str_len = strlen($string);
for ($i=0; $i<$str_len; $i++) {
if (($count+1-$start)>$len) {
$str .= "...";
break;
} elseif ((ord(substr($string,$i,1)) <= 128) && ($count < $start)) {
$count++;
} elseif ((ord(substr($string,$i,1)) > 128) && ($count < $start)) {
$count = $count+2;
$i = $i+$byte-1;
} elseif ((ord(substr($string,$i,1)) <= 128) && ($count >= $start)) {
$str .= substr($string,$i,1);
$count++;
} elseif ((ord(substr($string,$i,1)) > 128) && ($count >= $start)) {
$str .= substr($string,$i,$byte);
$count = $count+2;
$i = $i+$byte-1;
}
}
return $str;
}
// Test
$str = "123456ֽ123456ַ123456ȡ";
for($i=0;$i<30;$i++){
echo "<br>".bite_str($str,$i,20);
}
?>
kriskra at gmail dot com ¶
12 years ago
The javascript charAt equivalent in php of felipe has a little bug. It's necessary to compare the type (implicit) aswell or the function returns a wrong result:
<?php
function charAt($str,$pos) {
return (substr($str,$pos,1) !== false) ? substr($str,$pos,1) : -1;
}
?>
php_net at thomas dot trella dot de ¶
15 years ago
I needed to cut a string after x chars at a html converted utf-8 text (for example Japanese text like 嬰謰弰脰欰罏).
The problem was, the different length of the signs, so I wrote the following function to handle that.
Perhaps it helps.
<?php
function html_cutstr ($str, $len)
{
if (!preg_match('/\&#[0-9]*;.*/i', $str))
{
$rVal = strlen($str, $len);
break;
}
$chars = 0;
$start = 0;
for($i=0; $i < strlen($str); $i++)
{
if ($chars >= $len)
break;
$str_tmp = substr($str, $start, $i-$start);
if (preg_match('/\&#[0-9]*;.*/i', $str_tmp))
{
$chars++;
$start = $i;
}
}
$rVal = substr($str, 0, $start);
if (strlen($str) > $start)
$rVal .= " ...";
return $rVal;
}
?>
sajjad at sajjad dot biz ¶
11 years ago
Substring utf-8 strings!
very simple!
<?php
function substru($str,$from,$len){
return preg_replace('#^(?:[\x00-\x7F]|[\xC0-\xFF][\x80-\xBF]+){0,'. $from .'}'.'((?:[\x00-\x7F]|[\xC0-\xFF][\x80-\xBF]+){0,'. $len .'}).*#s','$1', $str);
}
?>
morgangalpin att gmail dotty com ¶
13 years ago
Adding the $limit parameter introduced a bug that was not present in the original. If $limit is small or negative, a string with a length exceeding the limit can be returned. The $limit parameter should be checked. It takes slightly more processing, but it is dwarfed in comparison to the use of strlen().
<?php
function short_name($str, $limit)
{
// Make sure a small or negative limit doesn't cause a negative length for substr().
if ($limit < 3)
{
$limit = 3;
}
// Now truncate the string if it is over the limit.
if (strlen($str) > $limit)
{
return substr($str, 0, $limit - 3) . '...';
}
else
{
return $str;
}
}
?>
kaj dot strom at kapsi dot fi ¶
11 years ago
One thing to keep in mind when using string indexes and UTF-8 is that string indexes are NOT multi-byte safe.
<?php
$string = 'äää1';
echo $string[3];
?>
Outputs:
¤
When it logically should output "1". This is not a bug, as PHP 'normal' string functions are not intended to be multi-byte safe. This can be solved by using this function
<?php
/**
*
* @param string $string String to "search" from
* @param int $index Index of the letter we want.
* @return string The letter found on $index.
*/
function charAt($string, $index){
if($index < mb_strlen($string)){
return mb_substr($string, $index, 1);
}
else{
return -1;
}
}
?>
Anonymous ¶
12 years ago
Split a string to an array of strings specified by an array of lengths:
<?php
function split_by_lengths($inString, $arrayLengths)
{
$output = array();
foreach ($arrayLengths as $oneLength)
{
$output[] = substr($inString, 0, $oneLength);
$inString = substr($inString, $oneLength);
}
return ($output);
}
?>
split_by_lengths('teststringtestteststring', array(4,6,4,4,6)) returns:
array('test','string','test','test','string')
Don't use it on user input without some error handling!
highstrike at gmail dot com ¶
13 years ago
Because i didnt see a function that would cut a phrase from a text (article or whatever) no matter where, front/middle/end and add ... + keeping the words intact, i wrote this:
Usage:
- The parameter $value if array will need the whole text and the portion you want to start from, a string. EG: cuttext(array($text, $string), 20). If the string is "have" and is near the beginning of the text, the function will cut like "I have a car ...", if the string is in the middle somewhere it will cut like "... if you want to have your own car ..." and if its somewhere near the end it will cut like "... and you will have one."
- The $length parameter is self explanatory.
Note: if you have just a string "127hh43h2h52312453jfks2" and you want to cut it, just use the function like so: cuttext($string, 10) and it will cut it like "127hh43h2h..."
<?php
////////////////////////////////////////////////////////
// Function: cuttext
// Description: Cuts a string and adds ...
function cuttext($value, $length)
{
if(is_array($value)) list($string, $match_to) = $value;
else { $string = $value; $match_to = $value{0}; }
$match_start = stristr($string, $match_to);
$match_compute = strlen($string) - strlen($match_start);
if (strlen($string) > $length)
{
if ($match_compute < ($length - strlen($match_to)))
{
$pre_string = substr($string, 0, $length);
$pos_end = strrpos($pre_string, " ");
if($pos_end === false) $string = $pre_string."...";
else $string = substr($pre_string, 0, $pos_end)."...";
}
else if ($match_compute > (strlen($string) - ($length - strlen($match_to))))
{
$pre_string = substr($string, (strlen($string) - ($length - strlen($match_to))));
$pos_start = strpos($pre_string, " ");
$string = "...".substr($pre_string, $pos_start);
if($pos_start === false) $string = "...".$pre_string;
else $string = "...".substr($pre_string, $pos_start);
}
else
{
$pre_string = substr($string, ($match_compute - round(($length / 3))), $length);
$pos_start = strpos($pre_string, " "); $pos_end = strrpos($pre_string, " ");
$string = "...".substr($pre_string, $pos_start, $pos_end)."...";
if($pos_start === false && $pos_end === false) $string = "...".$pre_string."...";
else $string = "...".substr($pre_string, $pos_start, $pos_end)."...";
}
$match_start = stristr($string, $match_to);
$match_compute = strlen($string) - strlen($match_start);
}
return $string;
}
?>
ijavier aka(not imatech) igjav ¶
14 years ago
<?php
/*
An advanced substr but without breaking words in the middle.
Comes in 3 flavours, one gets up to length chars as a maximum, the other with length chars as a minimum up to the next word, and the other considers removing final dots, commas and etcteteras for the sake of beauty (hahaha).
This functions were posted by me some years ago, in the middle of the ages I had to use them in some corporations incorporated, with the luck to find them in some php not up to date mirrors. These mirrors are rarely being more not up to date till the end of the world... Well, may be am I the only person that finds usef not t bre word in th middl?
Than! (ks)
This is the calling syntax:
snippet(phrase,[max length],[phrase tail])
snippetgreedy(phrase,[max length before next space],[phrase tail])
*/
function snippet($text,$length=64,$tail="...") {
$text = trim($text);
$txtl = strlen($text);
if($txtl > $length) {
for($i=1;$text[$length-$i]!=" ";$i++) {
if($i == $length) {
return substr($text,0,$length) . $tail;
}
}
$text = substr($text,0,$length-$i+1) . $tail;
}
return $text;
}
// It behaves greedy, gets length characters ore goes for more
function snippetgreedy($text,$length=64,$tail="...") {
$text = trim($text);
if(strlen($text) > $length) {
for($i=0;$text[$length+$i]!=" ";$i++) {
if(!$text[$length+$i]) {
return $text;
}
}
$text = substr($text,0,$length+$i) . $tail;
}
return $text;
}
// The same as the snippet but removing latest low punctuation chars,
// if they exist (dots and commas). It performs a later suffixal trim of spaces
function snippetwop($text,$length=64,$tail="...") {
$text = trim($text);
$txtl = strlen($text);
if($txtl > $length) {
for($i=1;$text[$length-$i]!=" ";$i++) {
if($i == $length) {
return substr($text,0,$length) . $tail;
}
}
for(;$text[$length-$i]=="," || $text[$length-$i]=="." || $text[$length-$i]==" ";$i++) {;}
$text = substr($text,0,$length-$i+1) . $tail;
}
return $text;
}
/*
echo(snippet("this is not too long to run on the column on the left, perhaps, or perhaps yes, no idea") . "<br>");
echo(snippetwop("this is not too long to run on the column on the left, perhaps, or perhaps yes, no idea") . "<br>");
echo(snippetgreedy("this is not too long to run on the column on the left, perhaps, or perhaps yes, no idea"));
*/
?>
feedback at realitymedias dot com ¶
14 years ago
This function can replace substr() in some situations you don't want to cut right in the middle of a word. strtrim will cut between words when it is possible choosing the closest possible final string len to return. the maxoverflow parameter lets you choose how many characters can overflow past the maxlen parameter.
<?php
function strtrim($str, $maxlen=100, $elli=NULL, $maxoverflow=15) {
global $CONF;
if (strlen($str) > $maxlen) {
if ($CONF["BODY_TRIM_METHOD_STRLEN"]) {
return substr($str, 0, $maxlen);
}
$output = NULL;
$body = explode(" ", $str);
$body_count = count($body);
$i=0;
do {
$output .= $body[$i]." ";
$thisLen = strlen($output);
$cycle = ($thisLen < $maxlen && $i < $body_count-1 && ($thisLen+strlen($body[$i+1])) < $maxlen+$maxoverflow?true:false);
$i++;
} while ($cycle);
return $output.$elli;
}
else return $str;
}
?>
Anonymous ¶
17 years ago
If you want to substring the middle of a string with another and keep the words intact:
<?php
/**
* Reduce a string by the middle, keeps whole words together
*
* @param string $string
* @param int $max (default 50)
* @param string $replacement (default [...])
* @return string
* @author david at ethinkn dot com
* @author loic at xhtml dot ne
* @author arne dot hartherz at gmx dot net
*/
function strMiddleReduceWordSensitive ($string, $max = 50, $rep = '[...]') {
$strlen = strlen($string);
if ($strlen <= $max)
return $string;
$lengthtokeep = $max - strlen($rep);
$start = 0;
$end = 0;
if (($lengthtokeep % 2) == 0) {
$start = $lengthtokeep / 2;
$end = $start;
} else {
$start = intval($lengthtokeep / 2);
$end = $start + 1;
}
$i = $start;
$tmp_string = $string;
while ($i < $strlen) {
if ($tmp_string[$i] == ' ') {
$tmp_string = substr($tmp_string, 0, $i) . $rep;
$return = $tmp_string;
}
$i++;
}
$i = $end;
$tmp_string = strrev ($string);
while ($i < $strlen) {
if ($tmp_string[$i] == ' ') {
$tmp_string = substr($tmp_string, 0, $i);
$return .= strrev ($tmp_string);
}
$i++;
}
return $return;
return substr($string, 0, $start) . $rep . substr($string, - $end);
}
echo strMiddleReduceWordSensitive ('ABCDEEF GHIJK LLKJHKHKJHKL HGHFK sdfasdfsdafsdf sadf asdf sadf sad s', 30) . "\n";
// Returns: ABCDEEF GHIJK[...]asdf sadf sad s (33 chrs)
echo strMiddleReduceWordSensitive ('ABCDEEF GHIJK LLKJHKHKJHKL HGHFK sdfasdfsdafsdf sadf asdf sadf sad s', 30, '...') . "\n";
// Returns: ABCDEEF GHIJK...asdf sadf sad s (32 chrs)
?>
mr.davin ¶
12 years ago
Simple use of substr to determine possession:
<?php
function possessive ($word) {
return $word.(substr($word, -1) == 's' ? "'" : "'s");
}
// Davis => Davis'
// Paul => Paul's
?>
fengdingbo at gmail dot com ¶
7 years ago
<?php
$a = 'abc';
$php = 'ok123';
$str = microtime(TRUE);
for($i=0;$i<=1000000;$i++)
$a = substr($php,1,1);
echo microtime(true)-$str,"\n";
$str = microtime(TRUE);
for($i=0;$i<=1000000;$i++)
$a = $php[1];
echo microtime(true)-$str;
?>
output:
0.26694822311401
0.10447096824646
koczkahun at gmail dot com ¶
6 years ago
For those who cannot use mb_substr for any reasons, here is a solution for Unicode strings:
function substr_unicode($str, $s, $l = null)
{
$r = '/^.{'.(int)$s.'}(.';
$r .= ($l === null) ? '*)$' : '{'.(int)$l.'})';
$r .= '/su';
preg_match($r, $str, $o); return $o[1];
}
It is EXTREMELY fast compared to the array_slice + join method suggested before, and moderately slower than mb_substr.
Note: you cannot use negative values.
Note 2: use mb_substr whenever you can. Only use this workaround if you can not use the library.
persisteus at web dot de ¶
14 years ago
Here is also a nice (but a bit slow) alternative for colorizing an true color image:
<?php
// $colorize = hexadecimal code in String format, f.e. "10ffa2"
// $im = the image that have to be computed
$red = hexdec(substr($colorize, 0, 2));
$green = hexdec(substr($colorize, 2, 2));
$blue = hexdec(substr($colorize, 4, 2));
$lum_c = floor(($red*299 + $green*587 + $blue*144) / 1000);
for ($i = 0; $i < $lum_c; $i++)
{
$r = $red * $i / $lum_c;
$g = $green * $i / $lum_c;
$b = $blue * $i / $lum_c;
$pal[$i] = $r<<16 | $g<<8 | $b;
}
$pal[$lum_c] = $red<<16 | $green<<8 | $blue;
for ($i = $lum_c+1; $i < 255; $i++)
{
$r = $red + (255-$red) * ($i-$lum_c) / (255-$lum_c);
$g = $green + (255-$green) * ($i-$lum_c) / (255-$lum_c);
$b = $blue + (255-$blue) * ($i-$lum_c) / (255-$lum_c);
$pal[$i] = $r<<16 | $g<<8 | $b;
}
$sy = imagesy($im);
$sx = imagesx($im);
for($y=0;$y<$sy;$y++)
{
for($x=0;$x<$sx;$x++)
{
$rgba = imagecolorat($im, $x, $y);
$a = ($rgba & 0x7F000000) >> 24;
$r = ($rgba & 0xFF0000) >> 16;
$g = ($rgba & 0x00FF00) >> 8;
$b = ($rgba & 0x0000FF);
$lum = floor(($r*299+$g*587+$b*144)/1000);
imagesetpixel($im, $x, $y, $a<<24 | $pal[$lum]);
}
}
?>
