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(PHP 4, PHP 5)
strstr — Findet das erste Vorkommen eines Strings
Gibt den Teil der Zeichenkette haystack ab dem ersten Vorkommen von needle bis zum Ende von haystack zurück.
Hinweis:
Diese Funktion unterscheidet zwischen Groß- und Kleinschreibung. Soll die Suche nicht zwischen Groß- und Kleinschreibung unterscheiden, verwenden Sie stristr().
Hinweis:
Wenn Sie nur herausfinden möchten, ob ein bestimmter needle innerhalb von haystack vorkommt, verwenden Sie stattdessen die schnellere und weniger speicherintensive Funktion strpos().
Die Eingabezeichenkette.
Ist needle kein String, wird der Parameter in einen Integerwert konvertiert, der dem Ordinalwert des Zeichens entspricht.
Ist der Wert auf TRUE gesetzt, gibt strstr() den Teil von haystack zurück, der sich vor dem ersten Vorkommen von needle befindet.
Gibt einen Teil der Zeichenkette zurück. Wird needle nicht gefunden, wird FALSE zurückgegeben.
| Version | Beschreibung |
|---|---|
| 5.3.0 | Der optionale Parameter before_needle wurde hinzugefügt. |
| 4.3.0 | strstr() ist nun binary safe. |
Beispiel #1 strstr()-Beispiel
<?php
$email = 'name@example.com';
$domain = strstr($email, '@');
echo $domain; // Ausgabe: @example.com
$user = strstr($email, '@', true); // Ab PHP 5.3.0
echo $user; // Ausgabe: name
?>
Added the optional parameter before_needle.
Now supported in PHP_Compat through the php_compat_strstr() function.
See: http://pear.php.net/package/PHP_Compat
use it to emulate the before_needle php V5.3
<?php
//$h = haystack, $n = needle
function strstrb($h,$n){
return array_shift(explode($n,$h,2));
}
//sample
echo strstrb('qwe,asd,zxc',',');
// outputs: qwe
?>
works perfect !!!
use it to emulate the before_needle php V5.3
<?php
//$h = haystack, $n = needle
function strstrb($h,$n){
return strrev(array_pop(explode($n,strrev($h))));
}
//sample
echo strstrb('qwe,asd,zxc',',');
// outputs: qwe
?>
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));
}
?>
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 $result;
}
?>
If you want to emulate strstr's new before_needle parameter pre 5.3 strtok is faster than using strpos to find the needle and cutting with substr. The amount of difference varies with string size but strtok is always faster.
I simplified prafe at prafesplace dot com's function:
<?php
function strstrbi($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);
}
?>
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
?>
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
?>
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 $domain; // prints example.com
?>
Often you will need to find all occurrences of a string (for security escapes and such)
So I wrote this function to return an array with the locations of all the occurrences. Almost like an advanced strstr.
<?php
function findall($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.
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 = "För att klippa av en sträng som innehåller skandinaviska (eller Franska, för den delen) tecken, kan man göra såhär...";
$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:
$newstr";
?>
The above outputs this:
Without the decode-encode snippet:
För att klippa av en sträng som inneh&ar
With the decode-encode snippet:
För att klippa av en sträng som innehåller skandin
First post in this db ;)
Best regards, Mikael Rönn, FIN
When encoding ASCII strings to HTML size-limited strings, sometimes some HTML special chars were cut.
For example, when encoding "��" to a string of size 10, you would get: "à &a" => the second character is cut.
This function will remove any unterminated HTML special characters from the string...
<?php
function cut_html($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;
}
?>
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 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"
?>
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