strspn
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);
}
?>
strstr
(PHP 4, PHP 5)
strstr — Find first occurrence of a string
说明
string strstr
( string $haystack
, string $needle
, bool $before_needle
)
Returns part of haystack string from the first occurrence of needle to the end of haystack .
Note: This function is case-sensitive. For case-insensitive searches, use stristr().
Note: If you only want to determine if a particular needle occurs within haystack , use the faster and less memory intensive function strpos() instead.
参数
- 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 occurence of the needle .
返回值
Returns the portion of string, or FALSE if needle is not found.
更新日志
| 版本 | 说明 |
|---|---|
| 6.0.0 | Added the before_needle parameter. |
| 4.3.0 | strstr() was made binary safe. |
范例
Example#1 strstr() example
<?php
$email = 'name@example.com';
$domain = strstr($email, '@');
echo $domain; // prints @example.com
$user = strstr($email, '@', true);
echo $user; // prints name
?>
add a note
User Contributed Notesstrstr
tim
26-Nov-2007 08:42
26-Nov-2007 08:42
brett dot jr dot alton at gmail dot com
26-Nov-2007 12:02
26-Nov-2007 12:02
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 01:14
22-Nov-2007 01:14
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 07:22
10-Nov-2007 07:22
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 $domain; // prints example.com
?>
gigaman2003 at halfempty dot co dot uk
25-Feb-2007 04:48
25-Feb-2007 04:48
Often you will need to find all occurrences of a string (for security escapes and such)
So I wrote this function to return an array with the locations of all the occurrences. Almost like an advanced strstr.
<?php
function findall($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.
07-Jun-2005 12:13
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 = "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:
$newstr";
?>
The above outputs this:
Without the decode-encode snippet:
För att klippa av en sträng som inneh&ar
With the decode-encode snippet:
För att klippa av en sträng som innehåller skandin
First post in this db ;)
Best regards, Mikael Rnn, FIN
leo dot nard at free dot fr
24-May-2005 05:12
24-May-2005 05:12
When encoding ASCII strings to HTML size-limited strings, sometimes some HTML special chars were cut.
For example, when encoding "��" to a string of size 10, you would get: "à&a" => the second character is cut.
This function will remove any unterminated HTML special characters from the string...
<?php
function cut_html($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
22-Jan-2004 04:25
22-Jan-2004 04:25
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 07:37
15-Feb-2003 07:37
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"
?>