what the hell are you all doing. Wanna find the *next* last from a specific position because strrpos is useless with the "offset" option, then....
ex: find 'Z' in $str from position $p, backward...
while($p > -1 and $str{$p} <> 'Z') $p--;
Anyone will notice $p = -1 means: *not found* and that you must ensure a valid start offset in $p, that is >=0 and < string length. Doh
strrpos
(PHP 4, PHP 5)
strrpos — 文字列中に、ある文字が最後に現れる場所を探す
説明
int strrpos ( string $haystack, string $needle [, int $offset] )文字列 haystack の中で、 needle が最後に現れた位置を数字で返します。 この場合、needle は単一文字でなければならないことに 注意してください。needle に文字列が指定された場合、その文字列の最初の文字だけが使われます。
needle が見つからない場合、FALSE を返します。
"位置 0 に文字が見つかった" と "文字が見つからなかった" 場合の返り値は混同しやすいです。この違いを見分ける方法を以下に示します。
<?php
// PHP 4.0.0 以降の場合:
$pos = strrpos($mystring, "b");
if ($pos === false) { // 注意: 等号が 3 つ
// 見つからない...
}
// 4.0.0 より古いバージョンの場合:
$pos = strrpos($mystring, "b");
if (is_bool($pos) && !$pos) {
// 見つからない...
}
?>
needle が文字列でない場合は数値に変換されて、 その結果が検索対象の文字として適用されます。
注意: PHP 5.0.0 以降、 offset により文字列中の任意の文字位置から検索を開始することができます。 負の値を指定すると、文字の終端より前の任意の位置で検索を終了します。
注意: PHP 5.0.0 以降、needle は 1 文字以上の文字列を指定可能です。
パラメータ
- haystack
- needle
- offset
返り値
参考
| strpos() |
| strripos() |
| strrchr() |
| substr() |
| stristr() |
| strstr() |
strrpos
pb at tdcspace dot dk
23-Sep-2007 11:26
23-Sep-2007 11:26
brian at enchanter dot net
16-Jul-2007 11:47
16-Jul-2007 11:47
The documentation for 'offset' is misleading.
It says, "offset may be specified to begin searching an arbitrary number of characters into the string. Negative values will stop searching at an arbitrary point prior to the end of the string."
This is confusing if you think of strrpos as starting at the end of the string and working backwards.
A better way to think of offset is:
- If offset is positive, then strrpos only operates on the part of the string from offset to the end. This will usually have the same results as not specifying an offset, unless the only occurences of needle are before offset (in which case specifying the offset won't find the needle).
- If offset is negative, then strrpos only operates on that many characters at the end of the string. If the needle is farther away from the end of the string, it won't be found.
If, for example, you want to find the last space in a string before the 50th character, you'll need to do something like this:
strrpos($text, " ", -(strlen($text) - 50));
If instead you used strrpos($text, " ", 50), then you would find the last space between the 50th character and the end of the string, which may not have been what you were intending.
jafet at g dot m dot a dot i dot l dot com
13-Apr-2007 11:08
13-Apr-2007 11:08
It would probably be good if someone would care to merge these little thoughts together...
<?php
function super_conforming_strrpos($haystack, $needle, $offset = 0)
{
# Why does strpos() do this? Anyway...
if(!is_string($needle)) $needle = ord(intval($needle));
if(!is_string($haystack)) $haystack = strval($haystack);
# Setup
$offset = intval($offset);
$hlen = strlen($haystack);
$nlen = strlen($needle);
# Intermezzo
if($nlen == 0)
{
trigger_error(__FUNCTION__.'(): Empty delimiter.', E_USER_WARNING);
return false;
}
if($offset < 0)
{
$haystack = substr($haystack, -$offset);
$offset = 0;
}
elseif($offset >= $hlen)
{
trigger_error(__FUNCTION__.'(): Offset not contained in string.', E_USER_WARNING);
return false;
}
# More setup
$hrev = strrev($haystack);
$nrev = strrev($needle);
# Search
$pos = strpos($hrev, $nrev, $offset);
if($pos === false) return false;
else return $hlen - $nlen - $pos;
}
?>
jafet at g dot m dot a dot i dot l dot com
12-Apr-2007 05:57
12-Apr-2007 05:57
Full strpos() functionality, by yours truly.
<?php
function conforming_strrpos($haystack, $needle, $offset = 0)
{
# Why does strpos() do this? Anyway...
if(!is_string($needle)) $needle = ord(intval($needle));
$haystack = strval($haystack);
# Parameters
$hlen = strlen($haystack);
$nlen = strlen($needle);
# Come on, this is a feature too
if($nlen == 0)
{
trigger_error(__FUNCTION__.'(): Empty delimiter.', E_USER_WARNING);
return false;
}
$offset = intval($offset);
$hrev = strrev($haystack);
$nrev = strrev($needle);
# Search
$pos = strpos($hrev, $nrev, $offset);
if($pos === false) return false;
else return $hlen - $nlen - $pos;
}
?>
Note that $offset is evaluated from the end of the string.
Also note that conforming_strrpos() performs some five times slower than strpos(). Just a thought.
mijsoot_at_gmail_dot_com
06-Mar-2007 06:43
06-Mar-2007 06:43
To begin, i'm sorry for my English.
So, I needed of one function which gives me the front last position of a character.
Then I said myself that it should be better to make one which gives the "N" last position.
$return_context = "1173120681_0__0_0_Mijsoot_Thierry";
// Here i need to find = "Mijsoot_Thierry"
//echo $return_context."<br />";// -- DEBUG
function findPos($haystack,$needle,$position){
$pos = strrpos($haystack, $needle);
if($position>1){
$position --;
$haystack = substr($haystack, 0, $pos);
$pos = findPos($haystack,$needle,$position);
}else{
// echo $haystack."<br />"; // -- DEBUG
return $pos;
}
return $pos;
}
var_dump(findPos($return_context,"_",2)); // -- TEST
Christ Off
30-Jan-2007 03:50
30-Jan-2007 03:50
Function to truncate a string
Removing dot and comma
Adding ... only if a is character found
function TruncateString($phrase, $longueurMax = 150) {
$phrase = substr(trim($phrase), 0, $longueurMax);
$pos = strrpos($phrase, " ");
$phrase = substr($phrase, 0, $pos);
if ((substr($phrase,-1,1) == ",") or (substr($phrase,-1,1) == ".")) {
$phrase = substr($phrase,0,-1);
}
if ($pos === false) {
$phrase = $phrase;
}
else {
$phrase = $phrase . "...";
}
return $phrase;
}
Guilherme Garnier
15-Jan-2007 07:44
15-Jan-2007 07:44
Actually, there is a little problem on your code: if $needle is not found inside $haystack, the function should return FALSE, but it is actually returning strlen($haystack) - strlen($needle). Here is a corrected version of it:
<?php
function stringrpos($haystack,$needle,$offset=NULL)
{
if (strpos($haystack,$needle,$offset) === FALSE)
return FALSE;
return strlen($haystack)
- strpos( strrev($haystack) , strrev($needle) , $offset)
- strlen($needle);
}
?>
php NO at SPAMMERS willfris SREMMAPS dot ON nl
21-Dec-2006 11:48
21-Dec-2006 11:48
<?php
/*******
** Maybe the shortest code to find the last occurence of a string, even in php4
*******/
function stringrpos($haystack,$needle,$offset=NULL)
{
return strlen($haystack)
- strpos( strrev($haystack) , strrev($needle) , $offset)
- strlen($needle);
}
// @return -> chopped up for readability.
?>
purpleidea
27-Nov-2006 05:07
27-Nov-2006 05:07
I was having some issues when I moved my code to run it on a different server.
The earlier php version didn't support more than one character needles, so tada, bugs. It's in the docs, i'm just pointing it out in case you're scratching your head for a while.
dmitry dot polushkin at gmail dot com
07-Nov-2006 09:04
07-Nov-2006 09:04
Back to previous post... if you are using the PHP >=5.2 then use the simply:
<?php pathinfo($filename, PATHINFO_EXTENSION); ?>
dmitry dot polushkin at gmail dot com
04-Nov-2006 03:05
04-Nov-2006 03:05
Returns the filename's string extension, else if no extension found returns false.
Example: filename_extension('some_file.mp3'); // mp3
Faster than the pathinfo() analogue in two times.
<?php
function filename_extension($filename) {
$pos = strrpos($filename, '.');
if($pos===false) {
return false;
} else {
return substr($filename, $pos+1);
}
}
?>
kavih7 at yahoo dot com
09-Jun-2006 04:53
09-Jun-2006 04:53
###################################################
#
# DESCRIPTION:
# This function returns the last occurance of a string,
# rather than the last occurance of a single character like
# strrpos does. It also supports an offset from where to
# start the searching in the haystack string.
#
# ARGS:
# $haystack (required) -- the string to search upon
# $needle (required) -- the string you are looking for
# $offset (optional) -- the offset to start from
#
# RETURN VALS:
# returns integer on success
# returns false on failure to find the string at all
#
###################################################
function strrpos_string($haystack, $needle, $offset = 0)
{
if(trim($haystack) != "" && trim($needle) != "" && $offset <= strlen($haystack))
{
$last_pos = $offset;
$found = false;
while(($curr_pos = strpos($haystack, $needle, $last_pos)) !== false)
{
$found = true;
$last_pos = $curr_pos + 1;
}
if($found)
{
return $last_pos - 1;
}
else
{
return false;
}
}
else
{
return false;
}
}
shimon at schoolportal dot co dot il
04-May-2006 03:31
04-May-2006 03:31
In strrstr function in php 4 there is also no offset.
<?
// by Shimon Doodkin
function chrrpos($haystack, $needle, $offset=false)
{
$needle=$needle[0];
$l=strlen($haystack);
if($l==0) return false;
if($offset===false) $offset=$l-1;
else
{
if($offset>$l) $offset=$l-1;
if($offset<0) return false;
}
for(;$offset>0;$offset--)
if($haystack[$offset]==$needle)
return $offset;
return false;
}
?>
clan_ghw2 at hotmail dot com
03-Feb-2006 04:28
03-Feb-2006 04:28
Brian below is incorrect about strrpos on different platforms.
Tested on Home PC (win32 + PHP 5.1.2) and Web Server (linux + 4.4.1)
echo strrpos("blah.blahannila","blaha");
returns 5 on windows
returns 5 on linux
Could've been a bug with an earlier PHP version, however the latest version of PHP returns position of the beginning of the string we're trying to find.
-Thaddeus
nh_handyman
22-Sep-2005 07:59
22-Sep-2005 07:59
As noted in some examples below, strrpos does not act the same on every platform!
On Linux, it returns the position of the end of the target
On Windows, it returns the position of the start of the target
strrpos ("c:/somecity/html/t.php")
returns 11 on Windows
returns 16 on Linux
Brian
gordon at kanazawa-gu dot ac dot jp
14-Sep-2005 01:56
14-Sep-2005 01:56
The "find-last-occurrence-of-a-string" functions suggested here do not allow for a starting offset, so here's one, tried and tested, that does:
function my_strrpos($haystack, $needle, $offset=0) {
// same as strrpos, except $needle can be a string
$strrpos = false;
if (is_string($haystack) && is_string($needle) && is_numeric($offset)) {
$strlen = strlen($haystack);
$strpos = strpos(strrev(substr($haystack, $offset)), strrev($needle));
if (is_numeric($strpos)) {
$strrpos = $strlen - $strpos - strlen($needle);
}
}
return $strrpos;
}
genetically altered mastermind at gmail
23-Aug-2005 02:30
23-Aug-2005 02:30
Very handy to get a file extension:
$this->data['extension'] = substr($this->data['name'],strrpos($this->data['name'],'.')+1);
fab
10-Aug-2005 08:07
10-Aug-2005 08:07
RE: hao2lian
There are a lot of alternative - and unfortunately buggy - implementations of strrpos() (or last_index_of as it was called) on this page. This one is a slight modifiaction of the one below, but it should world like a *real* strrpos(), because it returns false if there is no needle in the haystack.
<?php
function my_strrpos($haystack, $needle) {
$index = strpos(strrev($haystack), strrev($needle));
if($index === false) {
return false;
}
$index = strlen($haystack) - strlen($needle) - $index;
return $index;
}
?>
lwoods
07-Aug-2005 04:03
07-Aug-2005 04:03
If you are a VBScript programmer ("ex-" of course), you will find that 'strrpos' doesn't work like the VBScript 'instrRev' function.
Here is the equivalent function:
VBScript:
k=instrrev(s,">",j);
PHP Equivalent of the above VBScript:
$k=strrpos(substr($s,0,$j),'>');
Comments:
You might think (I did!) that the following PHP function call would be the equivant of the above VBScript call:
$kk=strrpos($s,'>',$j);
NOPE! In the above PHP call, $j defines the position in the string that should be considered the BEGINNING of the string, whereas in the VBScript call, j is to be considered the END of the string, as far as this search is concerned. Anyway, the above 'strrpos' with the 'substr' will work.
(Probably faster to write a for loop!)
hao2lian
03-Aug-2005 11:50
03-Aug-2005 11:50
Yet another correction on the last_index_of function algorithm:
function last_index_of($haystack, $needle) {
$index = strpos(strrev($haystack), strrev($needle));
$index = strlen($haystack) - strlen($needle) - $index;
return $index;
}
"strlen(index)" in the most recent one should be "strlen($needle)".
jonas at jonasbjork dot net
06-Apr-2005 05:25
06-Apr-2005 05:25
I needed to remove last directory from an path, and came up with this solution:
<?php
$path_dir = "/my/sweet/home/";
$path_up = substr( $path_dir, 0, strrpos( $path_dir, '/', -2 ) )."/";
echo $path_up;
?>
Might be helpful for someone..
09-Mar-2005 04:14
In the below example, it should be substr, not strrpos.
<PHP?
$filename = substr($url, strrpos($url, '/') + 1);
?>
escii at hotmail dot com ( Brendan )
11-Jan-2005 12:12
11-Jan-2005 12:12
I was immediatley pissed when i found the behaviour of strrpos ( shouldnt it be called charrpos ?) the way it is, so i made my own implement to search for strings.
<?
function proper_strrpos($haystack,$needle){
while($ret = strrpos($haystack,$needle))
{
if(strncmp(substr($haystack,$ret,strlen($needle)),
$needle,strlen($needle)) == 0 )
return $ret;
$haystack = substr($haystack,0,$ret -1 );
}
return $ret;
}
?>
griffioen at justdesign dot nl
18-Nov-2004 03:57
18-Nov-2004 03:57
If you wish to look for the last occurrence of a STRING in a string (instead of a single character) and don't have mb_strrpos working, try this:
function lastIndexOf($haystack, $needle) {
$index = strpos(strrev($haystack), strrev($needle));
$index = strlen($haystack) - strlen(index) - $index;
return $index;
}
nexman at playoutloud dot net
08-Oct-2004 01:22
08-Oct-2004 01:22
Function like the 5.0 version of strrpos for 4.x.
This will return the *last* occurence of a string within a string.
function strepos($haystack, $needle, $offset=0) {
$pos_rule = ($offset<0)?strlen($haystack)+($offset-1):$offset;
$last_pos = false; $first_run = true;
do {
$pos=strpos($haystack, $needle, (intval($last_pos)+(($first_run)?0:strlen($needle))));
if ($pos!==false && (($offset<0 && $pos <= $pos_rule)||$offset >= 0)) {
$last_pos = $pos;
} else { break; }
$first_run = false;
} while ($pos !== false);
if ($offset>0 && $last_pos<$pos_rule) { $last_pos = false; }
return $last_pos;
}
If my math is off, please feel free to correct.
- A positive offset will be the minimum character index position of the first character allowed.
- A negative offset will be subtracted from the total length and the position directly before will be the maximum index of the first character being searched.
returns the character index ( 0+ ) of the last occurence of the needle.
* boolean FALSE will return no matches within the haystack, or outside boundries specified by the offset.
harlequin AT gmx DOT de
27-May-2004 01:59
27-May-2004 01:59
this is my function for finding a filename in a URL:
<?php
function getfname($url){
$pos = strrpos($url, "/");
if ($pos === false) {
// not found / no filename in url...
return false;
} else {
// Get the string length
$len = strlen($url);
if ($len < $pos){
print "$len / $pos";
// the last slash we found belongs to http:// or it is the trailing slash of a URL
return false;
} else {
$filename = substr($url, $pos+1, $len-$pos-1);
}
}
return $filename;
}
?>
tsa at medicine dot wisc dot edu
25-May-2004 09:17
25-May-2004 09:17
What the heck, I thought I'd throw another function in the mix. It's not pretty but the following function counts backwards from your starting point and tells you the last occurrance of a mixed char string:
<?php
function strrposmixed ($haystack, $needle, $start=0) {
// init start as the end of the str if not set
if($start == 0) {
$start = strlen($haystack);
}
// searches backward from $start
$currentStrPos=$start;
$lastFoundPos=false;
while($currentStrPos != 0) {
if(!(strpos($haystack,$needle,$currentStrPos) === false)) {
$lastFoundPos=strpos($haystack,$needle,$currentStrPos);
break;
}
$currentStrPos--;
}
if($lastFoundPos === false) {
return false;
} else {
return $lastFoundPos;
}
}
?>
dreamclub2000 at hotmail dot com
05-Feb-2004 05:17
05-Feb-2004 05:17
This function does what strrpos would if it handled multi-character strings:
<?php
function getLastStr($hay, $need){
$getLastStr = 0;
$pos = strpos($hay, $need);
if (is_int ($pos)){ //this is to decide whether it is "false" or "0"
while($pos) {
$getLastStr = $getLastStr + $pos + strlen($need);
$hay = substr ($hay , $pos + strlen($need));
$pos = strpos($hay, $need);
}
return $getLastStr - strlen($need);
} else {
return -1; //if $need wasn�t found it returns "-1" , because it could return "0" if it�s found on position "0".
}
}
?>
ZaraWebFX
15-Oct-2003 03:06
15-Oct-2003 03:06
this could be, what derek mentioned:
<?
function cut_last_occurence($string,$cut_off) {
return strrev(substr(strstr(strrev($string), strrev($cut_off)),strlen($cut_off)));
}
// example: cut off the last occurence of "limit"
$str = "select delta_limit1, delta_limit2, delta_limit3 from table limit 1,7";
$search = " limit";
echo $str."\n";
echo cut_last_occurence($str,"limit");
?>
lee at 5ss dot net
29-Aug-2003 11:21
29-Aug-2003 11:21
I should have looked here first, but instead I wrote my own version of strrpos that supports searching for entire strings, rather than individual characters. This is a recursive function. I have not tested to see if it is more or less efficient than the others on the page. I hope this helps someone!
<?php
//Find last occurance of needle in haystack
function str_rpos($haystack, $needle, $start = 0){
$tempPos = strpos($haystack, $needle, $start);
if($tempPos === false){
if($start == 0){
//Needle not in string at all
return false;
}else{
//No more occurances found
return $start - strlen($needle);
}
}else{
//Find the next occurance
return str_rpos($haystack, $needle, $tempPos + strlen($needle));
}
}
?>
ara at bluemedia dot us
14-Jul-2003 05:09
14-Jul-2003 05:09
derek@slashview.com notes a great replacement for strrpos because of the single character needle limitation in the strrpos function. He made a slight error in the code. He adds the length of the needle string instead of subtracting it from the final position. The function should be:
<?php
function strlastpos($haystack, $needle) {
# flip both strings around and search, then adjust position based on string lengths
return strlen($haystack) - strlen($needle) - strpos(strrev($haystack), strrev($needle));
}
?>
no_spammage_at_wwwcrm_dot_com
25-Apr-2003 12:07
25-Apr-2003 12:07
This function does what strrpos would if it handled multi-character strings:
<?php
//function recurses until it finds last instance of $needle in $haystack
function getLastStr($haystack, $needle, $first_time=1){
$test=strstr($haystack, $needle);//is the needle there?
if ($test) return getLastStr($test, $needle, 0);//see if there is another one?
else if ($first_time) return false;//there is no occurence at all
else return $haystack;//that was the last occurence
}
?>
FIE
15-Feb-2003 10:03
15-Feb-2003 10:03
refering to the comment and function about lastIndexOf()...
It seemed not to work for me the only reason I could find was the haystack was reversed and the string wasnt therefore it returnt the length of the haystack rather than the position of the last needle... i rewrote it as fallows:
<?php
function strlpos($f_haystack,$f_needle) {
$rev_str = strrev($f_needle);
$rev_hay = strrev($f_haystack);
$hay_len = strlen($f_haystack);
$ned_pos = strpos($rev_hay,$rev_str);
$result = $hay_len - $ned_pos - strlen($rev_str);
return $result;
}
?>
this one fallows the strpos syntax rather than java's lastIndexOf.
I'm not positive if it takes more resources assigning all of those variables in there but you can put it all in return if you want, i dont care if i crash my server ;).
~SILENT WIND OF DOOM WOOSH!
rob at pulpchat dot com
23-Jan-2003 07:23
23-Jan-2003 07:23
For those of you coming from VBScript, I have
converted the instrrev function to PHP:
<?php
function instrrev($n,$s) {
$x=strpos(chr(0).strrev($n),$s)+0;
return (($x==0) ? 0 : strlen($n)-$x+1);
}
?>
Remember that, unlike PHP and Javascript, VBScript
returns 0 for no string found and 1 for the first
character position, etc.
Hopefully this will save some time if you are
converting ASP pages to PHP.
php dot net at insite-out dot com
18-Dec-2002 04:47
18-Dec-2002 04:47
I was looking for the equivalent of Java's lastIndexOf(). I couldn't find it so I wrote this:
<?php
/*
Method to return the last occurrence of a substring within a
string
*/
function last_index_of($sub_str,$instr) {
if(strstr($instr,$sub_str)!="") {
return(strlen($instr)-strpos(strrev($instr),$sub_str));
}
return(-1);
}
?>
It returns the numerical index of the substring you're searching for, or -1 if the substring doesn't exist within the string.
su.noseelg@naes, only backwards
14-Dec-2002 03:39
14-Dec-2002 03:39
Maybe I'm the only one who's bothered by it, but it really bugs me when the last line in a paragraph is a single word. Here's an example to explain what I don't like:
The quick brown fox jumps over the lazy
dog.
So that's why I wrote this function. In any paragraph that contains more than 1 space (i.e., more than two words), it will replace the last space with ' '.
<?php
function no_orphans($TheParagraph) {
if (substr_count($TheParagraph," ") > 1) {
$lastspace = strrpos($TheParagraph," ");
$TheParagraph = substr_replace($TheParagraph," ",$lastspace,1);
}
return $TheParagraph;
}
?>
So, it would change "The quick brown fox jumps over the lazy dog." to "The quick brown fox jumps over the lazy dog." That way, the last two words will always stay together.
DONT SPAM vardges at iqnest dot com
31-Oct-2002 06:22
31-Oct-2002 06:22
that function can be modified to this
<?php
function strrpos_str ($string, $searchFor, $startFrom = 0)
{
$addLen = strlen ($searchFor);
$endPos = $startFrom - $addLen;
while (true)
{
if (($newPos = strpos ($string, $searchFor, $endPos + $addLen)) === false) break;
$endPos = $newPos;
}
return ($endPos >= 0) ? $endPos : false;
}
// example
$str = "abcabcabc";
$search = "ab";
$pos = strrpos_str ($str, $search);
if ($pos === false) echo "not found";
else echo $pos; // returns 6 in this case
?>
29-May-2002 04:46
Cause:
Find position of last occurrence of a string in a string...
and I needed it, I hacked a little code to do this:
Maybe it is helpful for you.
<?php
function _strrpos_needle($sourcestring,$needle){
/* just for easier understanding */
$tempString=$sourcestring;
do {
$tempPos=strpos($tempString,$needle);
$tempString=substr($tempString,$tempPos+strlen($needle));
$realPos=$realPos+$tempPos;
} while (!is_bool($tempPos));
return $realPos;
}
?>
derek at slashview dot com
02-Feb-2002 09:06
02-Feb-2002 09:06
To find the position of the start of the last occurence of a string, we can do this:
$pos=strlen($haystack) - (strpos(strrev($haystack), strrev($needle)) + strlen($needle));
The idea is to reverse both $needle and $haystack, use strpos to find the first occurence of $needle in $haystack, then count backwards by the length of $needle. Finally, subtract $pos from length of $haystack. A lot easier to figure out if you use a test string to visualize it. :)