strtok

strspn

Last updated: Fri, 20 Nov 2009

strstr

(PHP 4, PHP 5)

strstr — Find first occurrence of a string

Opis

string strstr ( string $haystack , mixed $needle [, bool $before_needle = false ] )

Returns part of haystack string from the first occurrence of needle to the end of haystack .

Informacja: This function is case-sensitive. For case-insensitive searches, use stristr().

Informacja: If you only want to determine if a particular needle occurs within haystack , use the faster and less memory intensive function strpos() instead.

Parametry

haystack: The input string.
needle: If needle is not a string, it is converted to an integer and applied as the ordinal value of a character.
before_needle: If TRUE (the default is FALSE), strstr() returns the part of the haystack before the first occurrence of the needle .

Zwracane wartości

Returns the portion of string, or FALSE if needle is not found.

Rejestr zmian

Wersja	Opis
5.3.0	Added the optional parameter `before_needle` .
4.3.0	strstr() was made binary safe.

Przykłady

Przykład #1 strstr() example


<?php
$email  = 'name@example.com';
$domain = strstr($email, '@');
echo $domain; // prints @example.com

$user = strstr($email, '@', true); // As of PHP 5.3.0
echo $user; // prints name
?>

Zobacz też:

preg_match() - Perform a regular expression match
stristr() - Case-insensitive strstr
strpos() - Find position of first occurrence of a string
strrchr() - Znajduje ostatnie występowanie znaku w łańcuchu znaków
substr() - Return part of a string

strtok

strspn

Last updated: Fri, 20 Nov 2009

add a note User Contributed Notes
strstr

Marcio Angel Medina
14-Aug-2009 08:05


use it to emulate the before_needle php V5.3



<?php

//$h = haystack, $n = needle 

function strstrb($h,$n){

    return array_shift(explode($n,$h,2));

}

//sample

echo strstrb('qwe,asd,zxc',',');

// outputs: qwe

?>



works perfect !!!

Marcio Angel Medina
08-Aug-2009 04:28


use it to emulate the before_needle php V5.3

<?php

//$h = haystack, $n = needle 

function strstrb($h,$n){

    return strrev(array_pop(explode($n,strrev($h))));

}

//sample

echo strstrb('qwe,asd,zxc',',');

// outputs: qwe

?>

sheyd at advisa dot fr
09-Jul-2009 09:19


Before PHP 5.3 to emulate $before_needle you can already have this :


 


<?php


function rstrstr($haystack, $needle)


{


    return substr(strrev(strstr(strrev($haystack), strrev($needle))), 0, -strlen($needle));


}


?>

dpac dot mittal at gmail dot com
30-May-2009 12:37


You can emulate the $before_needle before v5.3 in a very very simple way. Just applied a bit of common sense.





Here's the code:





<?php


function strstrbef($haystack, $needle)


{


    $needle=strrev($needle);


    $haystack=strrev($haystack);


    $result=strstr($haystack,$needle);


    $result=substr($haystack,strlen($needle));


    $result=strrev($result);


    return $result;


}


?>

w3b_monk3y at yahoo dot com
20-Jan-2009 08:28


If you want to emulate strstr's new before_needle parameter pre 5.3 strtok is faster than using strpos to find the needle and cutting with substr. The amount of difference varies with string size but strtok is always faster.

tim
26-Nov-2007 12:42


I simplified prafe at prafesplace dot com's function:



<?php

function strstrbi($haystack, $needle, $before_needle=FALSE, $include_needle=TRUE, $case_sensitive=FALSE) {

 //Find the position of $needle

 if($case_sensitive) {

  $pos=strpos($haystack,$needle);

 } else {

  $pos=strpos(strtolower($haystack),strtolower($needle));

 }

 

 //If $needle not found, abort

 if($pos===FALSE) return FALSE;

 

 //Adjust $pos to include/exclude the needle

 if($before_needle==$include_needle) $pos+=strlen($needle);

 

 //get everything from 0 to $pos?

 if($before_needle) return substr($haystack,0,$pos);

 

 //otherwise, go from $pos to end

 return substr($haystack,$pos);

}

?>



It's now 600 bytes, down from 2k.



Also, here are replacements for strstr and stristr:



<?php

function strstr($haystack, $needle, $before_needle=FALSE) {

 //Find position of $needle or abort

 if(($pos=strpos($haystack,$needle))===FALSE) return FALSE;



 if($before_needle) return substr($haystack,0,$pos+strlen($needle));

 else return substr($haystack,$pos);

}



function stristr($haystack, $needle, $before_needle=FALSE) {

 //Find position of $needle or abort

 if(($pos=strpos(strtolower($haystack),strtolower($needle)))===FALSE) return FALSE;



 if($before_needle) return substr($haystack,0,$pos+strlen($needle));

 else return substr($haystack,$pos);

}

?>

brett dot jr dot alton at gmail dot com
25-Nov-2007 04:02


For the needle_before (first occurance) parameter when using PHP 5.x or less, try:



<?php

$haystack = 'php-homepage-20071125.png';

$needle = '-';

$result = substr($haystack, 0, strpos($haystack, $needle)); // $result = php

?>

prafe at prafesplace dot com
22-Nov-2007 05:14


If you want to use the $before_needle parameter that's only in PHP 5.3.0, I found a way to use it in lower versions.





The code is a bit hefty, but it works. It also has added $include_needle and $case_sensitive.





<?php


// ==== I don't guarantee this is faster than the PHP 6 before needle, ====


// ====  but it works for PHP below 6 atleast. ====


// ==== IT ALSO HAS INCLUDE NEEDLE BOOLEAN.. ====


function strstrbi($haystack,$needle,$before_needle,


$include_needle,$case_sensitive)


{


  $strstr = ($case_sensitive) ? 'strstr' : 'stristr';


  if($before_needle!=true && $before_needle!=false && isset($before_needle)){


      die('PHP: Error in function '.chr(39).'$strstrbi'. chr(39).' :  parameter '. chr(39).'$before_needle'.chr(39).' is not a supplied as a boolean.');


  } // END BOOLEAN CHECK '$before_needle'





  if($include_needle!=true && $include_needle!=false && isset($include_needle)){


    die('PHP: Error in function '.chr(39).'$strstrbi'. chr(39).' : parameter '. chr(39).'$include_needle'.chr(39). ' is not a supplied as a boolean.');


  } // END BOOLEAN CHECK '$include_needle'





  if($case_sensitive!=true && $case_sensitive!=false && isset($case_sensitive)){


    die('PHP: Error in function '.chr(39).'$strstrbi' .chr(39).' : parameter '. chr(39).'$case_sensitive'.chr(39).' is not a supplied as a boolean.');


  } // END BOOLEAN CHECK '$case_sensitive'





  if(!isset($before_needle)){


    $before_needle=false;


  }





  if(!isset($include_needle)){


    $include_needle=true;


  }





  if(!isset($case_sensitive)){


    $case_sensitive=false;


  }





  switch($before_needle){


    case true:


      switch($include_needle){


        case true:


          $temp=strrev($haystack);


          $ret=strrev(substr($strstr($temp,$needle),0));


          break;


        // END case true : $include_needle


        case false:


          $temp=strrev($haystack);


          $ret=strrev(substr($strstr($temp,$needle),1));


          break;


        // END case false : $include_needle


      }


      break;


    // END case true : $before_needle


    case false:


      switch($include_needle){


        case true:


          $ret=$strstr($haystack,$needle);


          break;


        // END case true: $include_needle


        case false:


          $ret=substr($strstr($haystack,$needle),1);


          break;


        // END case false: $include_needle


    }


    break;


    // END case false : $before_needle


  }





  if(!empty($ret)){


    return $ret;


  }else{


    return false;


  }


}


// === END FUNCTION 'strstrbi'





// Example





$email  = 'user@example.com';


$domain = strstrbi($email, '@', false, false, false);


echo $domain; // prints example.com





$user = strstrbi($email, '@', true, false, false);


echo $user; // prints user


?>

root at mantoru dot de
10-Nov-2007 11:22


Please note that $needle is included in the return string, as shown in the example above. This ist not always desired behavior, _especially_ in the mentioned example. Use this if you want everything AFTER $needle.



<?php

function strstr_after($haystack, $needle, $case_insensitive = false) {

    $strpos = ($case_insensitive) ? 'stripos' : 'strpos';

    $pos = $strpos($haystack, $needle);

    if (is_int($pos)) {

        return substr($haystack, $pos + strlen($needle));

    }

    // Most likely false or null

    return $pos;

}



// Example

$email = 'name@example.com';

$domain = strstr_after($email, '@');

echo $domain; // prints example.com

?>

gigaman2003 at halfempty dot co dot uk
24-Feb-2007 08:48


Often you will need to find all occurrences of a string (for security escapes and such)





So I wrote this function to return an array with the locations of all the occurrences. Almost like an advanced strstr.





<?php


function findall($needle, $haystack)


{


    //Setting up


    $buffer=''; //We will use a 'frameshift' buffer for this search


    $pos=0; //Pointer


    $end = strlen($haystack); //The end of the string


    $getchar=''; //The next character in the string


    $needlelen=strlen($needle); //The length of the needle to find (speeds up searching)


    $found = array(); //The array we will store results in


    


    while($pos<$end)//Scan file


    {


        $getchar = substr($haystack,$pos,1); //Grab next character from pointer


        if($getchar!="\n" || buffer<$needlelen) //If we fetched a line break, or the buffer is still smaller than the needle, ignore and grab next character


        {


            $buffer = $buffer . $getchar; //Build frameshift buffer


            if(strlen($buffer)>$needlelen) //If the buffer is longer than the needle


            {


                $buffer = substr($buffer,-$needlelen);//Truncunate backwards to needle length (backwards so that the frame 'moves')


            }


            if($buffer==$needle) //If the buffer matches the needle


            {


                $found[]=$pos-$needlelen+1; //Add the location of the needle to the array. Adding one fixes the offset.


            }


        }


        $pos++; //Increment the pointer


    }


    if(array_key_exists(0,$found)) //Check for an empty array


    {


        return $found; //Return the array of located positions


    }


    else


    {


        return false; //Or if no instances were found return false


    }


}


?>





Haven't had the chance to speed test it, but many optimizations should be possible. It just works enough for me. Hope it saves someone a lot of time.

06-Jun-2005 04:13


suggestion for [leo dot nard at free dot fr]:

to be able to cut the string without having the html entities being cut in half, use this instead:



<?php



$oldstr = "F&ouml;r att klippa av en str&auml;ng som inneh&aring;ller skandinaviska (eller Franska, f&ouml;r den delen) tecken, kan man g&ouml;ra s&aring;h&auml;r...";



$length = 50;



# First, first we want to decode the entities (to get them as usual chars), then cut the string at for example 50 chars, and then encoding the result of that again.



# Or, as I had it done, in one line:

$newstr = htmlentities(substr(html_entity_decode($oldstr), 0, $length));

$newstr2 = substr($oldstr, 0, $length);

# It's not quite as much code as the snippet you've coded to remove the half-portions... ;)

# Hopefully somebody finds this useful!

echo "Without the decode-encode snippet:

$newstr2



With the decode-encode snippet:

$newstr";

?>



The above outputs this:



Without the decode-encode snippet:

F&ouml;r att klippa av en str&auml;ng som inneh&ar



With the decode-encode snippet:

F&ouml;r att klippa av en str&auml;ng som inneh&aring;ller skandin



First post in this db ;) 

Best regards, Mikael R�nn, FIN

leo dot nard at free dot fr
24-May-2005 09:12


When encoding ASCII strings to HTML size-limited strings, sometimes some HTML special chars were cut.





For example, when encoding "��" to a string of size 10, you would get: "à&a" => the second character is cut.





This function will remove any unterminated HTML special characters from the string...





<?php


function cut_html($string)


{


    $a=$string;





    while ($a = strstr($a, '&'))


    {


        echo "'".$a."'\n";


        $b=strstr($a, ';'); 


        if (!$b)


        {


            echo "couper...\n";


            $nb=strlen($a);


            return substr($string, 0, strlen($string)-$nb);


        }


        $a=substr($a,1,strlen($a)-1);


    }


    return $string;


}


?>

Romuald Brunet
21-Jan-2004 08:25


Regarding the note of the manual concerning the speed of strstr against strpos, for people who wants to check a needle occurs within haystack, it apprears that strstr() is in facts faster than strpos().



Example:

<?php

// [VERY] Quick email check:

if ( strstr("email@domain.tld", "@") ) {

// Ok

}

?>



is faster than



<?php

if ( strpos("email@domain.tld", "@") !== FALSE ) {

// Ok

}



Without using the true equality with !==, strpos() is faster. But then if the haystack starts with needle the condition whould not be met.

php at silisoftware dot com
14-Feb-2003 11:37


PHP versions before 4.3.0 (tested on 4.2.2 and 4.2.3) return the $haystack from $needle only up to the first null character. So for example:





<?php


$string = strstr("one#two\x00three", "#");


// PHP 4.2.x:  $string contains "#two"


// PHP 4.3.0:  $string contains "#two\x00three"


?>





If you're trying to match nulls, you will probably get back an empty string:





<?php


$string = strstr("one#two\x00three", "\x00");


// PHP 4.2.x:  $string contains ""


// PHP 4.3.0:  $string contains "\x00three"


?>

add a note

strtok

strspn

Last updated: Fri, 20 Nov 2009