strstr

(PHP 4, PHP 5)

strstr — Trouve la première occurrence dans une chaîne

Description

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

Retourne une sous-chaîne de haystack , allant de la première occurrence de needle jusqu'à la fin de la chaîne.

Note: strstr() est sensible à la casse. Pour une fonctionnalité identique, mais insensible à la casse, reportez-vous à stristr().

Note: Si vous voulez juste déterminer si un needle particulier se trouve dans la chaîne haystack , utilisez la fonction strpos() qui est plus rapide et qui consomme moins de ressources.

Liste de paramètres

haystack: La chaîne d'entrée.
needle: Si needle n'est pas une chaîne, elle sera convertie en entier, et utilisée comme code ascii du caractère correspondant.
before_needle: Si vaut TRUE (par défaut, vaut FALSE), strstr() retourne la partie de haystack avant la première occurrence de needle .

Valeurs de retour

Retourne la portion de la chaîne, ou FALSE si needle n'est pas trouvé.

Historique

Version	Description
5.3.0	Ajout du paramètre optionnel `before_needle` .
4.3.0	strstr() est maintenant compatible avec les données binaires.

Exemples

Exemple #1 Exemple avec strstr()


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

$user = strstr($email, '@', true); // Depuis PHP 5.3.0
echo $user; // Affiche : name
?>

Voir aussi

strtok

strspn

Last updated: Fri, 14 Nov 2008

add a note User Contributed Notes
strstr

tim
26-Nov-2007 01:42


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 05:02


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 06:14


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 12:22


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 09:48


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.



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 06:13


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 11:12


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: "&agrave;&a" => the second character is cut.



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



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 09:25


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
15-Feb-2003 12:37


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:



$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:



$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, 14 Nov 2008