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trim> <substr_replace
Last updated: Fri, 26 Sep 2008

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substr

(PHP 4, PHP 5)

substrВозвращает подстроку

Описание

string substr ( string $string , int $start [, int $length ] )

substr() возвращает подстроку строки string длиной length , начинающегося с start символа по счету.

Если start неотрицателен, возвращаемая подстрока начинается в позиции start от начала строки, считая от нуля. Например, в строке 'abcdef', в позиции 0 находится символ 'a', в позиции 2 - символ 'c', и т.д.

Пример #1 Пример использования substr()

<?php
$rest 
substr("abcdef"1);    // возвращает "bcdef"
$rest substr("abcdef"13); // возвращает "bcd"
$rest substr("abcdef"04); // возвращает "abcd"
$rest substr("abcdef"08); // возвращает "abcdef"

// к отдельным символам можно обращаться с помощью фигурных скобок
$string 'abcdef';
echo 
$string{0};                // выводит a
echo $string{3};                // выводит d
?>

Если start отрицательный, возвращаемая подстрока начинается с start символа с конца строки string .

Пример #2 Использование отрицательного start

<?php
$rest 
substr("abcdef", -1);    // возвращает "f"
$rest substr("abcdef", -2);    // возвращает "ef"
$rest substr("abcdef", -31); // возвращает "d"
?>

Если length положительный, возвращаемая строка будет не длиннее length символов. Если длина строки string меньше или равна start символов, возвращается FALSE.

Если length отрицательный, то будет отброшено указанное этим аргументом число символов с конца строки string . Если при этом позиция начала подстроки, определяемая аргументом start , находится в отброшенной части строки, возвращается пустая строка.

Пример #3 Использование отрицательного length

<?php
$rest 
substr("abcdef"0, -1);  // возвращает "abcde"
$rest substr("abcdef"2, -1);  // возвращает "cde"
$rest substr("abcdef"4, -4);  // возвращает ""
$rest substr("abcdef", -3, -1); // возвращает "de"
?>

См. также описание функций strrchr(), substr_replace(), ereg(), trim() и mb_substr().



trim> <substr_replace
Last updated: Fri, 26 Sep 2008
 
add a note add a note User Contributed Notes
substr
NULL_byte
19-Sep-2008 12:21
<?php

function insert_substr($str, $pos, $substr) {
   
$part1 = substr($str, 0, -$pos);
   
$part2 = substr($str, -$pos);
    return
$part1.$substr.$part2;
}

?>
baldaris69 at yahoo dot com
29-Aug-2008 09:57
***Caution newbie***
To extract a file Extension this fuction could be useful.

$file_extension = substr($filename , strrpos($filename , '. ') +1);

Suppose your file name is Baldaris.jpeg

strrpos will return the last dot position in the string 9 so

so the compiler will execute substr($filename , 10)

$file_extension will have value jpeg

pretty cool...

Cheer's

Baldaris
c dot 1 at smithies dot org
19-Aug-2008 05:33
The documentation no longer states what happens when length is omitted. It should state that in this case, the function returns whatever would have been returned if a length equal to the remaining length of the source string was supplied.
post [at] jannik - zappe [dot] de
05-Aug-2008 04:59
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 ;)
jamesvanboxtel at wsu dot edu
31-Jul-2008 11:17
Here is a quick function to get the substring of a string up to and including the last occurrence of $needle

<?php
function substrtruncate($string, $needle)
{
    return
substr($string, 0, strrpos($string, $needle)+1);
}

$current_dir = substrtruncate($_SERVER['SCRIPT_NAME'], '/');
?>
Anonymous
29-Jul-2008 08:18
I wrote this simple function

<?php
$input
= "hello world"
echo(limitchrmid($imput,10)) // hel ... rld

//limit chars middle
function limitchrmid($value,$lenght){
    if (
strlen($value) >= $lenght ){
       
$lenght_max = ($lenght/2)-3;
       
$start = strlen($value)- $lenght_max;
       
$limited = substr($value,0,$lenght_max);
       
$limited.= " ... ";                  
       
$limited.= substr($value,$start,$lenght_max);
    }
    else{
       
$limited = $value;
    }
    return
$limited;
}
?>
svihel
27-Jun-2008 10:09
joao dot martins at plako dot net
26-Mar-2008 09:14

ben at enemy dot dk
10-Feb-2008 05:48

Updated function. The previous one will return empty value if the $string has no letter spaces. This is usefull if some of your strings have only one word.

function cutText($string, $setlength) {
    $length = $setlength;
    if($length<strlen($string)){
        while (($string{$length} != " ") AND ($length > 0)) {
            $length--;
        }
        if ($length == 0) return substr($string, 0, $setlength);
        else return substr($string, 0, $length);
    }else return $string;
}
serzh at nm dot ru
03-Jun-2008 12:13
easy and quick way to limit length of a text by not cutting full words:

textLimit('some words', 7) is 'some...'

function textLimit($string, $length, $replacer = '...')
{
  if(strlen($string) > $length)
  return (preg_match('/^(.*)\W.*$/', substr($string, 0, $length+1), $matches) ? $matches[1] : substr($string, 0, $length)) . $replacer;
 
  return $string;
}
Someone
16-May-2008 07:54
In response to: "dev at arthurk dot com"

Your code:
<?php
      $file_basename
= substr($filename, 0, strripos($filename, '.')); // strip extention
     
$file_ext      = substr($filename, -1 * strripos($filename, '.'));
?>

The second line don't work.
This code work fine:

<?php
      $file_basename
= substr($filename, 0, strripos($filename, '.')); // strip extention
     
$file_ext      = substr($filename, strripos($filename, '.'));
?>

Example:
  $filename="anything.jpg"
  strripos($filename, '.'); -> position 8
  substr($filename, -1 * 8); -> "hing.jpg" (-8 chars from end)
But:
  substr($filename, 8); -> ".jpg" (starts in the char number 8)

Sorry for my english, and, "dev at arthurk dot com", sorry, i don't disturb you, only want contribute.

Open Source is revolution!!! -;)
dev at arthurk dot com
02-Apr-2008 08:34
Here is a quick and easy way to get the base name and the extension of a file. It also handles filenames like foo-1.0.1.tar (where foo-1.0.1 is the base, and .tar is the extension).

<?php
      $file_basename
= substr($filename, 0, strripos($filename, '.')); // strip extention
     
$file_ext      = substr($filename, -1 * strripos($filename, '.'));
?>

Notice the use of "strripos()" instead of "stripos()".

If you need to detect .tar.gz, etc. as the ext (starting at the first dot), substitute "stripos" for "strripos".
joao dot martins at plako dot net
26-Mar-2008 02:14
ben at enemy dot dk
10-Feb-2008 05:48

The function he wrote to cut text whithout cutting in middle of words, doesn't work if $lenght is smaller than $string size..
Just add a simple test and it works perfect for listing texts with a maximum chars:

function cutText($string, $length) {
    if($length<strlen($string)){
        while ($string{$length} != " ") {
            $length--;
        }
        return substr($string, 0, $length);
    }else return $string;
}
Anonymous
17-Mar-2008 12:53
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!
yorn at no dot spam at niroj.com
09-Mar-2008 06:59
kriskra's charAt script has the nifty feature that when $pos == -1, it will give the last letter of the string.

I am not sure (did not test), but I believe this code might be slightly faster:
<?php
/**
 * Function to get a single character from a string
 *
 * @param string $str String to get char from
 * @param integer $pos Get char from this position of $str. Should be zero or greater
 * @return mixed Integer -1 when $pos is out of range, otherwise the charater at position $pos.
 */
function charAt($str, $pos) {
    return (
$pos < 0 || $pos >= strlen($str)) ? -1 : $str{$pos};
}
?>
Please note that this version does NOT have this nifty feature.
When $pos == -1, result will be -1.
kriskra at gmail dot com
01-Mar-2008 02:21
The javascript charAt equivalent in php of felipe has a little bug. It's necessary to compare the type (implicit) aswell or the function returns a wrong result:
<?php
function charAt($str,$pos) {
    return (
substr($str,$pos,1) !== false) ? substr($str,$pos,1) : -1;
}
?>
Anonymous
23-Feb-2008 02:12
I've used the between, after, before, etc functions that biohazard put together for years and they work great.  I've also added to it a new function that I use a lot and thought others might like it as well.  It uses his before/after functions so they are required to use it.

<?
$example_html
= "<p>test1 Test2</p><title>hi there</title><p>Testing</p>";
$paragraph_text = multi_between('<p>', '</p>', $example_html);

//Prints an arry of:
//Array ( [1] => test1 Test2 [2] => Testing )
print_r($paragraph_text);

function
multi_between($this, $that, $inthat)
{
  
$counter = 0;
   while (
$inthat)
   {
     
$counter++;
     
$elements[$counter] = before($that, $inthat);
     
$elements[$counter] = after($this, $elements[$counter]);
     
$inthat = after($that, $inthat);
   }
   return
$elements;
}
//Get the help functions from biohazard's post below.
?>
ben at enemy dot dk
10-Feb-2008 05:48
Needed a method to cut text without cutting in middle of words, so made this little function to iterate back until a whitespace is found, and then cut the text from there.

function cutText($string, $length) {
    while ($string{$length} != " ") {
        $length--;
    }
    return substr($string, 0, $length);
}
highstrike at gmail dot com
06-Jan-2008 05:47
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;
}

?>
Jim
11-Oct-2007 12:03
Just want to note that if you are retrieving sub-strings of length zero, this function breaks in the base case (the source being an empty string):

    substr('123',0,0) returns string(0) ""
    substr('12',0,0) returns string(0) ""
    substr('1',0,0) returns string(0) ""

but

    substr('',0,0) returns bool(false)

Although this is the documented behavior, I would consider it unexpected in many circumstances.
morgangalpin att gmail dotty com
24-Sep-2007 07:55
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
$str;
    }
  }
?>
corphi
13-Sep-2007 01:06
I prefer
<?php
function short_name($str, $limit)
{
    return
strlen($str) > $limit ? substr($str, 0, $limit - 3) . '...' : $str;
}
?>

Now, every returned string has a maximum length of $limit chars (instead of $limit + 3).
Petez
31-Aug-2007 12:56
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.
ein at anti-logic dot com
31-Jul-2007 12:06
If you need to divide a large string (binary data for example) into segments, a much quicker way to do it is to use streams and the php://memory stream wrapper.

For example, if you have a large string in memory, write it to a memory stream like
<?php
$segment_length
= 8192; // this is how long our peice will be
$fp = fopen("php://memory", 'r+'); // create a handle to a memory stream resource
fputs($fp, $payload); // write data to the stream
$total_length=ftell($fp); // get the length of the stream
$payload_chunk = fread ( $fp, $segment_length  );
?>

Working with large data sets, mine was 21MB, increased the speed several factors.
Robert Chapin
26-Jun-2007 11:40
All the references to "curly braces" on this page appear to be obsolete.

According to http://us.php.net/manual/en/language.types.string.php

"Using square array-brackets is preferred because the {braces} style is deprecated as of PHP 6."

Robert Chapin
Chapin Information Services
lanny at freemail dot hu
26-Jun-2007 12:31
Starting from version 5.2.3 if $start is negative and larger then the length of the string, the result is an empty string, while in earlier versions the result was the string itself!

substr ("abcdef", -1000);

result in 5.2.0
'abcdef'

result in 5.2.3
''

This is a small inconsistency, one of those things that makes the life of a PHP programmer like hell.
Antoine
10-May-2007 06:08
The functions submitted below are a waste of time and memory. To convert a string to an integer or a trimmed float, use the built in conversion instead of parsing the string, e.g :

<?php
$x
= "27.2400";
echo (float)
$x; // 27.24
echo (int)$x; // 27
?>
siavashg at gmail dot com
06-Mar-2007 10:51
A further addition to Jean-Felix function to extract data between delimeters.

The previous function wouldn't return the correct data if the delimeters used where long than one char. Instead the following function should do the job.

<?php
function extractBetweenDelimeters($inputstr,$delimeterLeft,$delimeterRight) {
  
$posLeft  = stripos($inputstr,$delimeterLeft)+strlen($delimeterLeft);
  
$posRight = stripos($inputstr,$delimeterRight,$posLeft+1);
   return 
substr($inputstr,$posLeft,$posRight-$posLeft);
}
?>
Jean-Felix, Bern
28-Feb-2007 04:10
If you need to extract information in a string between delimeters then you can use this:

Inputstring is:
"Heidi Klum Supermodel" <info@HeidiKlum.com>

Here the script
<?php
   $emailadresse
= "\"Heidi Klum Supermodel\" <info@HeidiKlum.com>";
  
  
$outputvalue = extractBetweenDelimeters($emailadresse,"\"","\"");
   echo 
$outputvalue// shows Heidi Klum Supermodel
  
echo "<br>";
  
$outputvalue = extractBetweenDelimeters($emailadresse,"<",">");
   echo 
$outputvalue// shows info@HeidiKlum.com
  
  
  
function extractBetweenDelimeters($inputstr,$delimeterLeft,$delimeterRight) {
   
$posLeft  = stripos($inputstr,$delimeterLeft)+1;
   
$posRight = stripos($inputstr,$delimeterRight,$posLeft+1);
    return 
substr($inputstr,$posLeft,$posRight-$posLeft);
   }
  
?>
ijavier aka(not imatech) igjav
14-Feb-2007 11:20
/*
    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"));
*/
persisteus at web dot de
13-Feb-2007 04:45
Here is also a nice (but a bit slow) alternative for colorizing an true color image:

// $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]);
  }
}
egingell at sisna dot com
19-Oct-2006 12:19
<?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);
}

?>
feedback at realitymedias dot com
16-Oct-2006 02:47
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;
}

?>
joseph dot morphy at gmail dot com
16-Aug-2006 06:31
<?php
//function to get a substring between between two other substrings

function substring_between($haystack,$start,$end) {
    if (
strpos($haystack,$start) === false || strpos($haystack,$end) === false) {
        return
false;
    } else {
       
$start_position = strpos($haystack,$start)+strlen($start);
       
$end_position = strpos($haystack,$end);
        return
substr($haystack,$start_position,$end_position-$start_position);
    }
}

//use of this function to get the title of an html document

$handle = fopen($filename, 'r');
$contents = fread($handle, filesize($filename));
fclose($handle);

$contents = htmlspecialchars($contents);
$title = substring_between($contents,'&lt;title&gt;','&lt;/title&gt;');

?>
rodrigo at fabricadeideias dot com
17-Mar-2006 10:17
It might be obvious to some but I took some time to figure it out that you can't call
<?php
$text
= substr($text, 0, -0);
?>
and expect $text to be unchanged.

A bit of context might make the issue clearer. I'm calculating how many characters I need to chop of the end of the string and them I call substr as
<?php
$text
= substr($text, 0, -$charactersToChop);
?>
Sometimes $charactersToChop is set to 0 and in this case I wanted $text to be unchanged. The problem is that in this case $text gets set to an empty string.

Why? Because -0 is the same as 0 and substr($text, 0, 0) obviously returns an empty string.

In case someone want a fix:
<?php
if ($charactersToChop) {
 
$text = substr($text, 0, -$charactersToChop);
}
?>

That's it.
shadzar
13-Feb-2006 02:21
a function to read in a file and split the string into its individual characters and display them as images for a webcounter.

can be used anywhere you need to split a string where a seperator is not present and versions where the str_split() function is also not present.

<?php
//start counter
$filename = "counter_file.txt";
$pathtoiamges = "http://www.yoursite.com/counter/";//where is your iamges
$extension = ".gif";//what filetype are your images in
//--------------do not change below this line-------------------
$counter=file_get_contents($filename);
$counter++;
$count=$counter;
$current=0;
$visit=array("");//array to hold individual characters
//split string into individual characters
//same as str_split($str) in PHP5
while (strlen($count)>0)
    {
   
$current++;
   
$visit[$current]=substr($count,0,1);//get current digit
   
$count=substr($count,1,strlen($count));//reduce number string to remove last stored digit
   
}
//display images of digits
foreach ($visit as $vis)
    {
    if (
$vis!=""){echo "<img src=/old?u=http%3A%2F%2Ffr.php.net%2Fmanual%2Fru%2F%5C&y=1999"". $pathtoimages . $vis . .$extension . "\">";}
    }
$list = fopen($filename, "w+");
fwrite($list, $counter);
fclose($list);
//end counter
?>

requires a file to store the counter and 10 images to represent the digits (0-9) if used as a counter.
wishie at gmail dot com
04-Feb-2006 03:37
Here's a function I wrote that'll insert a string into another string with an offset.

// $insertstring - the string you want to insert
// $intostring - the string you want to insert it into
// $offset - the offset

function str_insert($insertstring, $intostring, $offset) {
    $part1 = substr($intostring, 0, $offset);
    $part2 = substr($intostring, $offset);
   
    $part1 = $part1 . $insertstring;
    $whole = $part1 . $part2;
    return $whole;
}
Bradley from California
10-Jan-2006 10:34
Add on to "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.

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;
}
eallik at hotmail dot com
05-Jan-2006 04:22
Be careful when comparing the return value of substr to FALSE. FALSE may be returned even if the output is a valid string.

substr("0", 0); // equals "0", comparision with FALSE evaluates to true, because "0" == 0 == FALSE
mr at bbp dot biz
14-Dec-2005 11:54
Here's a little addon to the html_substr function posted by fox.

Now it counts only chars outside of tags, and doesn't cut words.

Note: this will only work in xhtml strict/transitional due to the checking of "/>" tags and the requirement of quotations in every value of a tag. It's also only been tested with the presence of br, img, and a tags, but it should work with the presence of any tag.

<?php
function html_substr($posttext, $minimum_length = 200, $length_offset = 20, $cut_words = FALSE, $dots = TRUE) {
  
   
// $minimum_length:
    // The approximate length you want the concatenated text to be  
 

    // $length_offset:
    // The variation in how long the text can be in this example text
    // length will be between 200 and 200-20=180 characters and the
    // character where the last tag ends

    // Reset tag counter & quote checker
   
$tag_counter = 0;
   
$quotes_on = FALSE;
   
// Check if the text is too long
   
if (strlen($posttext) > $minimum_length) {
       
// Reset the tag_counter and pass through (part of) the entire text
       
$c = 0;
        for (
$i = 0; $i < strlen($posttext); $i++) {
           
// Load the current character and the next one
            // if the string has not arrived at the last character
           
$current_char = substr($posttext,$i,1);
            if (
$i < strlen($posttext) - 1) {
               
$next_char = substr($posttext,$i + 1,1);
            }
            else {
               
$next_char = "";
            }
           
// First check if quotes are on
           
if (!$quotes_on) {
               
// Check if it's a tag
                // On a "<" add 3 if it's an opening tag (like <a href...)
                // or add only 1 if it's an ending tag (like </a>)
               
if ($current_char == '<') {
                    if (
$next_char == '/') {
                       
$tag_counter += 1;
                    }
                    else {
                       
$tag_counter += 3;
                    }
                }
               
// Slash signifies an ending (like </a> or ... />)
                // substract 2
               
if ($current_char == '/' && $tag_counter <> 0) $tag_counter -= 2;
               
// On a ">" substract 1
               
if ($current_char == '>') $tag_counter -= 1;
               
// If quotes are encountered, start ignoring the tags
                // (for directory slashes)
               
if ($current_char == '"') $quotes_on = TRUE;
            }
            else {
               
// IF quotes are encountered again, turn it back off
               
if ($current_char == '"') $quotes_on = FALSE;
            }
          
           
// Count only the chars outside html tags
           
if($tag_counter == 2 || $tag_counter == 0){
               
$c++;
            }          
                          
           
// Check if the counter has reached the minimum length yet,
            // then wait for the tag_counter to become 0, and chop the string there
           
if ($c > $minimum_length - $length_offset && $tag_counter == 0 && ($next_char == ' ' || $cut_words == TRUE)) {
               
$posttext = substr($posttext,0,$i + 1);              
                if(
$dots){
                  
$posttext .= '...';
                }
                return
$posttext;
            }
        }
    }  
    return
$posttext;
}

?>
felipe at spdata dot com dot br
29-Nov-2005 01:48
JavaScript charAt PHP equivalent

<?php
   
function charAt($str, $pos)
    {
        return (
substr($str, $pos, 1)) ? substr($str, $pos, 1) : -1;
    }
?>

If found, return the charecter at the specified position, otherwise return -1
18-Oct-2005 04:47
<?php
function utf8_substr($str,$from,$len){
# utf8 substr
# www.yeap.lv
 
return preg_replace('#^(?:[\x00-\x7F]|[\xC0-\xFF][\x80-\xBF]+){0,'.$from.'}'.
                      
'((?:[\x00-\x7F]|[\xC0-\xFF][\x80-\xBF]+){0,'.$len.'}).*#s',
                      
'$1',$str);
}
?>
frank at jkelloggs dot dk
25-Jul-2005 11:37
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));
   }
}
?>
julius at infoguiden dot no
04-Jul-2005 08:23
This function shortens the string down to maximum lengt defined in $max_lengt. If the string is longer the function finds the last occurance of a space and adds three dots at the end to illustrate that it is more text. If the string is without spaces it stops at exacly max lengt, also adding three dots. If the string is shorter than max lengt it returns the string as it is. This is useful for previewing long strings.

function str_stop($string, $max_length){
    if (strlen($string) > $max_length){
        $string = substr($string, 0, $max_length);
        $pos = strrpos($string, " ");
        if($pos === false) {
               return substr($string, 0, $max_length)."...";
           }
        return substr($string, 0, $pos)."...";
    }else{
        return $string;
    }
}
php_net at thomas dot trella dot de
29-Jun-2005 05:07
I needed to cut a string after x chars at a  html converted utf-8 text (for example Japanese text like &#23344;&#35632;&#24368;&#33072;&#27440;&#32591;).
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;
}
?>
ivanhoe011 at gmail dot com
08-Jun-2005 05:31
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..
rob NOSPAM at clancentric dot net
07-Jun-2005 12:43
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.

<?
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).'...';
    }
}
?>
bleakwind at msn dot com
25-May-2005 07:11
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);   
}
?>
fanfatal at fanfatal dot pl
17-May-2005 08:45
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 ;]
...
mike at go dot online dot pt
07-May-2005 05:15
matt at spcan dot com
03-May-2005 08:47
substr($lbar_html,0,-2); // does not work

and

substr($lbar_html, 0, -2); // works as expected

do not work the same.
woutermb at gmail dot com
21-Mar-2005 08:19
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.. :)
steve at unicycle dot co dot nz
14-Mar-2005 06:34
To quickly trim an optional trailing slash off the end of a path name:

if (substr( $path, -1 ) == '/') $path = substr( $path, 0, -1 );
cody at apparitiondesigns dot com
10-Mar-2005 10:02
I don't know if I didn't realize this because I'm not very smart - or if i just over looked it, but the string needs to be a string.  Not an integer.

ex.

<?php
$var
= 12345;
  echo
$var{0}; // outputs nothing at all

$var = '12345';
  echo
$var{0}; // out puts 1
?>
Matias from Argentina
24-Feb-2005 09:55
Hello,
Here you are a function to format your
numeric strings. Enjoy it.

<?php
function str_format_number($String, $Format){
    if (
$Format == '') return $String;
    if (
$String == '') return $String;

   
$Result = '';
   
$FormatPos = 0;
   
$StringPos = 0;
    While ((
strlen($Format) - 1) >= $FormatPos){
       
//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++;
    }

    return
$Result;
}

// For phone numbers at Buenos Aires, Argentina
// Example 1:
   
$String = "541143165500";
   
$Format = "+00 00 0000.000";
    Echo
str_format_number($String, $Format); // Returns "+54 11 4316.5500"

// Example 2:
   
$String = "541143165500";
   
$Format = "+00 00 0000.0000000";
    Echo
str_format_number($String, $Format); // Returns "+54 11 4316.5500"

// Example 3:
   
$String = "541143165500";
   
$Format = "+00 00 0000.000 a";
    Echo
str_format_number($String, $Format); // Returns "+54 11 4316.550 a"

?>

How it works explanation:

str_format_number($String, $Format)
Spects two parameters $String and $Format,
both should be strings.
$String: coulbe any kind of data type,
but it's oriented to numeric string, like
phone numbers.
$Format: should be a conjunction between
numbers (any one) and others caracters.

str_format_number takes each caracter
of $Format, if it isn't a number stores
it to be returned later, but if it is a
number takes the caracter of $String
placed in the position corresponding to
the amount of numbers in $Format so far
starting from zero.

If $Format has less numbers than $string
caracters the rest of the caracters at
the end of $String should be ignored.
If $Format has more numbers than $string
caracters the no caracter will be used,
so those will be ignored.
crashmanATgreenbomberDOTcom
22-Feb-2005 03:34
A fellow coder pointed out to me that $string{-n} will no longer return the character at postion -n is. Use $string{strlen($string) - n) instead.
andrewmclagan at gmail dot com
20-Feb-2005 10:58
Hi there here is a little function i wrote to limit the number of lines in a string, i could not find anything else like it out there   

function lineLimiter ($string = "", $max_lines = 1) {
   
         $string = ereg_replace("\n", "##", $string);
   
         $totalLines = (substr_count($string, '##') + 1);
   
         $string = strrev($string);
   
         $stringLength = strlen($string);
                    
         while ($totalLines > $max_lines) {
             $pos = 0;
             $pos = strpos ( $string, "##") + 2;
             //$pos = $pos - $stringLength;
             $string = substr($string, $pos);
             $totalLines--;   
         }
         $string = strrev($string);
          $string = ereg_replace("##", "\n", $string);
         return $string;
    }
Robert
13-Feb-2005 05:36
It is also good to use substr() to get a file extension when manipulating with files. For example:

<?php
$dir
= "/full/path/to/folder";
if(
is_dir($dir))
{
  if(
$dh = opendir($dir))
  {
    while((
$file = readdir($dh)) !== false)
    {
      if(
substr($file,strlen($file)-4,4) == ".txt")
      {
        echo
"Filename: $file<br/>\n";
      }
    }
   
closedir($dh);
  }
  else
  {
    echo
"Cannot open directory";
  }
}
else
{
  echo
"Cannot open directory";
}
?>

Hopefully this helps
mancini at nextcode dot org
05-Feb-2005 12:10
here are two functions to shrink a string to specified lenght , normally (stri...) or reversed (...ing)

<?php

//limit chars
 
function limitch($value,$lenght){
         if (
strlen($value) >= $lenght ){       
                 
$limited = substr($value,0,$lenght);
                 
$limited .= "...";                  
         }
         return
$limited;
  }
//limit chars reversed
 
function limitchrev($value,$lenght){
         if (
strlen($value) >= $lenght ){
                 
$start = strlen($value)- $lenght;
                 
$limited = "...";                  
                 
$limited .= substr($value,$start,$lenght);
         }
         return
$limited;
  }
 
?>
vitalic#pisem.net
15-Dec-2004 12:26
Split $string after each $pos, by $space
Example: <?php spaceStr('1836254','-',3); ?>
Would return '183-625-4';

<?php
function spaceStr($string,$space,$pos)
{
      
$cpos=$pos;
       while (
$cpos<strlen($string))
       {
        
$string=substr($string,0,$cpos).$space.substr($string,$cpos);
        
$cpos+=strlen($space)+$pos;
       };
       return
$string;
}

?>
kovacsendre at no_spam_thanks_kfhik dot hungary
02-Nov-2004 04:38
Here are the replacement functions for substr() and strlen() I use when support for html entities is required:

<?php

function html_strlen($str) {
 
$chars = preg_split('/(&[^;\s]+;)|/', $str, -1, PREG_SPLIT_NO_EMPTY | PREG_SPLIT_DELIM_CAPTURE);
  return
count($chars);
}

function
html_substr($str, $start, $length = NULL) {
  if (
$length === 0) return ""; //stop wasting our time ;)

  //check if we can simply use the built-in functions
 
if (strpos($str, '&') === false) { //No entities. Use built-in functions
   
if ($length === NULL)
      return
substr($str, $start);
    else
      return
substr($str, $start, $length);
  }

 
// create our array of characters and html entities
 
$chars = preg_split('/(&[^;\s]+;)|/', $str, -1, PREG_SPLIT_NO_EMPTY | PREG_SPLIT_DELIM_CAPTURE | PREG_SPLIT_OFFSET_CAPTURE);
 
$html_length = count($chars);

 
// check if we can predict the return value and save some processing time
 
if (
       (
$html_length === 0) /* input string was empty */ or
       (
$start >= $html_length) /* $start is longer than the input string */ or
       (isset(
$length) and ($length <= -$html_length)) /* all characters would be omitted */
    
)
    return
"";

 
//calculate start position
 
if ($start >= 0) {
   
$real_start = $chars[$start][1];
  } else {
//start'th character from the end of string
   
$start = max($start,-$html_length);
   
$real_start = $chars[$html_length+$start][1];
  }

  if (!isset(
$length)) // no $length argument passed, return all remaining characters
   
return substr($str, $real_start);
  else if (
$length > 0) { // copy $length chars
   
if ($start+$length >= $html_length) { // return all remaining characters
     
return substr($str, $real_start);
    } else {
//return $length characters
     
return substr($str, $real_start, $chars[max($start,0)+$length][1] - $real_start);
    }
  } else {
//negative $length. Omit $length characters from end
     
return substr($str, $real_start, $chars[$html_length+$length][1] - $real_start);
  }

}

?>

Example:
 
html_substr("&aacute;bla&#54;bla", 1, 4) -> "bla&#54;"

If you happen to find any bugs, please let me know.
lmak at NOSPAM dot iti dot gr
17-Aug-2004 08:59
Regarding windix's function to handle UTF-8 strings: one can use the "u" modifier on the regular expression so that the pattern string is treated as UTF-8 (available from PHP 4.1.0 or greater on Unix and from PHP 4.2.3 on win32). This way the function works for other encodings too (like Greek for example).

The modified function would read like this:

<?php
function utf8_substr($str,$start)
{
  
preg_match_all("/./u", $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));
   }
}
?>
fox at conskript dot server
11-Aug-2004 01:01
Here's a little bit of code to chop strings (with html tags) around a specified length while making sure no html tags are chopped. It also prevents chopping while a tag is still open.

Note: this will only work in xhtml strict/transitional due to the checking of "/>" tags and the requirement of quotations in every value of a tag. It's also only been tested with the presence of br, img, and a tags, but it should work with the presence of any tag.

<?php
function html_substr($posttext, $minimum_length, $length_offset) {
   
// The approximate length you want the concatenated text to be
   
$minimum_length = 200;
   
// The variation in how long the text can be
    // in this example text length will be between 200-10=190 characters
    // and the character where the last tag ends
   
$length_offset = 10;
   
// Reset tag counter & quote checker
   
$tag_counter = 0;
   
$quotes_on = FALSE;
   
// Check if the text is too long
   
if (strlen($posttext) > $minimum_length) {
       
// Reset the tag_counter and pass through (part of) the entire text
       
for ($i = 0; $i < strlen($posttext); $i++) {
           
// Load the current character and the next one
            // if the string has not arrived at the last character
           
$current_char = substr($posttext,$i,1);
            if (
$i < strlen($posttext) - 1) {
               
$next_char = substr($posttext,$i + 1,1);
            }
            else {
               
$next_char = "";
            }
           
// First check if quotes are on
           
if (!$quotes_on) {
               
// Check if it's a tag
                // On a "<" add 3 if it's an opening tag (like <a href...)
                // or add only 1 if it's an ending tag (like </a>)
               
if ($current_char == "<") {
                    if (
$next_char == "/") {
                                      
$tag_counter++;
                    }
                    else {
                       
$tag_counter = $tag_counter + 3;
                    }
                }
               
// Slash signifies an ending (like </a> or ... />)
                // substract 2
               
if ($current_char == "/") $tag_counter = $tag_counter - 2;
               
// On a ">" substract 1
               
if ($current_char == ">") $tag_counter--;
               
// If quotes are encountered, start ignoring the tags
                // (for directory slashes)
               
if ($current_char == "\"") $quotes_on = TRUE;
            }
            else {
               
// IF quotes are encountered again, turn it back off
               
if ($current_char == "\"") $quotes_on = FALSE;
            }
                           
           
// Check if the counter has reached the minimum length yet,
            // then wait for the tag_counter to become 0, and chop the string there
           
if ($i > $minimum_length - $length_offset && $tag_counter == 0) {
               
$posttext = substr($posttext,0,$i + 1) . "...";
                return
$posttext;
            }
        }
    }
             return
$posttext;
}
biohazard at online dot ge
15-May-2004 10:55
may be by following functions will be easyer to extract the
needed sub parts from a string:

 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 '['
 

<?

   
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));
    };

   
// USES
   
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);
    };

?>
phplist at boonedocks dot net
28-Aug-2003 10:39
If 'start' is negative and greater than the length of the string, PHP seems to return the first 'length' characters of the string. For example, substr('test',-10,1) returns 't'.
06-Jul-2003 02:39
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)
?>

trim> <substr_replace
Last updated: Fri, 26 Sep 2008
 
 
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