strspn
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
?>
strstr
(PHP 4, PHP 5)
strstr — 文字列が最初に現れる位置を見つける
説明
haystack の中で needle
が最初に現れる場所を含めてそこから文字列の終わりまでを返します。
注意:
この関数は大文字小文字を区別することに注意してください。 大文字小文字を区別しない検索を行う場合は、 stristr() を使用してください。
注意:
もし特定の
haystackにneedleがあるかどうかを調べるだけの場合、 より高速でメモリ消費も少ない strpos() を代わりに使用してください。
パラメータ
-
haystack -
入力文字列。
-
needle -
needleが文字列でない場合は、 それを整数に変換し、その番号に対応する文字として扱います。 -
before_needle -
TRUEにすると、 strstr() の返り値は、haystackの中で最初にneedleがあらわれる箇所より前の部分となります (needle は含めません)。
返り値
部分文字列を返します。
needle が見つからない場合は FALSE を返します。
変更履歴
| バージョン | 説明 |
|---|---|
| 5.3.0 |
オプションの before_needle パラメータが追加されました。
|
| 4.3.0 | strstr() がバイナリセーフとなりました。 |
例
例1 strstr() の例
<?php
$email = 'name@example.com';
$domain = strstr($email, '@');
echo $domain; // @example.com と表示します
$user = strstr($email, '@', true); // PHP 5.3.0 以降
echo $user; // name と表示します
?>
参考
- stristr() - 大文字小文字を区別しない strstr
- strrchr() - 文字列中に文字が最後に現れる場所を取得する
- strpos() - 文字列内の部分文字列が最初に現れる場所を見つける
- strpbrk() - 文字列の中から任意の文字を探す
- preg_match() - 正規表現によるマッチングを行う
add a note
User Contributed Notes
strstr - [14 notes]
brett dot jr dot alton at gmail dot com ¶
5 years ago
w3b_monk3y at yahoo dot com ¶
4 years ago
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.
php at silisoftware dot com ¶
10 years ago
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: $string contains "\x00three"
?>
xslidian at lidian dot info ¶
3 months ago
For those in need of the last occurrence of a string:
<?php
function strrstr($h, $n, $before = false) {
$rpos = strrpos($h, $n);
if($rpos === false) return false;
if($before == false) return substr($h, $rpos);
else return substr($h, 0, $rpos);
}
?>
gruessle at gmail dot com ¶
2 years ago
Been using this for years:
<?php
/**
*
* @author : Dennis T Kaplan
*
* @version : 1.0
* Date : June 17, 2007
* Function : reverse strstr()
* Purpose : Returns part of haystack string from start to the first occurrence of needle
* $haystack = 'this/that/whatever';
* $result = rstrstr($haystack, '/')
* $result == this
*
* @access public
* @param string $haystack, string $needle
* @return string
**/
function rstrstr($haystack,$needle)
{
return substr($haystack, 0,strpos($haystack, $needle));
}
?>
You could change it to:
rstrstr ( string $haystack , mixed $needle [, int $start] )
<?php
function rstrstr($haystack,$needle, $start=0)
{
return substr($haystack, $start,strpos($haystack, $needle));
}
?>
root at mantoru dot de ¶
5 years ago
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
?>
prafe at prafesplace dot com ¶
5 years ago
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
?>
peter at olds dot co ¶
1 year ago
I was in need of getting the first and last part of a string pre 5.3 so I wrote this:
<?php
$fir = $first = explode( " ", $cmd[1] );
unset( $fir[0] );
$end = ltrim( implode( " ", $fir ) );
?>
I needed it split with a " " but can obviously change for your needs. But with this format your output for the string:
"PHP is the best programming language out there"
Will give you the following results:
<?php
$first[0] // PHP
$end // is the best programming language out there
?>
Works really well :)
gigaman2003 at halfempty dot co dot uk ¶
6 years ago
Often you will need to find all occurrences of a string (for security escapes and such)
So I wrote this function to return an array with the locations of all the occurrences. Almost like an advanced strstr.
<?php
function findall($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 $found; //Return the array of located positions
}
else
{
return false; //Or if no instances were found return false
}
}
?>
Haven't had the chance to speed test it, but many optimizations should be possible. It just works enough for me. Hope it saves someone a lot of time.
leo dot nard at free dot fr ¶
7 years ago
When encoding ASCII strings to HTML size-limited strings, sometimes some HTML special chars were cut.
For example, when encoding "��" to a string of size 10, you would get: "à&a" => the second character is cut.
This function will remove any unterminated HTML special characters from the string...
<?php
function cut_html($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;
}
?>
xydon1 at yahoo dot com ¶
1 year ago
I explained this to my newbies the difference though it would be good to demonstrate this here. If you are evaluating a list you cannot use strstr as it looks for any occurance. The correct way is the function which evaluates a true or false on the exact value to check.
In the following example I have a list of promotion ids I want to evaluate whether or not a promotion exists:
<?php
//Wrong
$promotion = strstr("25,56","2");
if($promotion){
echo "found";
}else{
echo "not found";
}
//right
function detectPromotion($string,$promotion){
foreach(explode(",",$string) as $promotionToCheck){
echo "checkin ".$promotionToCheck."==".$promotion."<br/>";
if($promotionToCheck==$promotion){
$promotionFound=true;
}
}
return $promotionFound;
}
echo detectPromotion("2,56","2");
?>
tim ¶
5 years ago
I simplified prafe at prafesplace dot com's function:
<?php
function strstrbi($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);
}
?>
Anonymous ¶
7 years ago
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 Rnn, FIN
Romuald Brunet ¶
9 years ago
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.