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strpos

(PHP 4, PHP 5, PHP 7, PHP 8)

strpos查找字符串首次出现的位置

说明

strpos ( string $haystack , mixed $needle , int $offset = 0 ) : int

返回 needlehaystack 中首次出现的数字位置。

参数

haystack

在该字符串中进行查找。

needle

Prior to PHP 8.0.0, if needle is not a string, it is converted to an integer and applied as the ordinal value of a character. This behavior is deprecated as of PHP 7.3.0, and relying on it is highly discouraged. Depending on the intended behavior, the needle should either be explicitly cast to string, or an explicit call to chr() should be performed.

offset

如果提供了此参数,搜索会从字符串该字符数的起始位置开始统计。 如果是负数,搜索会从字符串结尾指定字符数开始。

返回值

返回 needle 存在于 haystack 字符串起始的位置(独立于 offset)。同时注意字符串位置是从0开始,而不是从1开始的。

如果没找到 needle,将返回 false

警告

此函数可能返回布尔值 false,但也可能返回等同于 false 的非布尔值。请阅读 布尔类型章节以获取更多信息。应使用 === 运算符来测试此函数的返回值。

更新日志

版本 说明
7.1.0 开始支持负数的 offset

范例

示例 #1 使用 ===

<?php
$mystring 
'abc';
$findme   'a';
$pos strpos($mystring$findme);

// 注意这里使用的是 ===。简单的 == 不能像我们期待的那样工作,
// 因为 'a' 是第 0 位置上的(第一个)字符。
if ($pos === false) {
    echo 
"The string '$findme' was not found in the string '$mystring'";
} else {
    echo 
"The string '$findme' was found in the string '$mystring'";
    echo 
" and exists at position $pos";
}
?>

示例 #2 使用 !==

<?php
$mystring 
'abc';
$findme   'a';
$pos strpos($mystring$findme);

// 使用 !== 操作符。使用 != 不能像我们期待的那样工作,
// 因为 'a' 的位置是 0。语句 (0 != false) 的结果是 false。
if ($pos !== false) {
     echo 
"The string '$findme' was found in the string '$mystring'";
         echo 
" and exists at position $pos";
} else {
     echo 
"The string '$findme' was not found in the string '$mystring'";
}
?>

示例 #3 使用位置偏移量

<?php
// 忽视位置偏移量之前的字符进行查找
$newstring 'abcdef abcdef';
$pos strpos($newstring'a'1); // $pos = 7, 不是 0
?>

注释

注意: 此函数可安全用于二进制对象。

参见

  • stripos() - 查找字符串首次出现的位置(不区分大小写)
  • strrpos() - 计算指定字符串在目标字符串中最后一次出现的位置
  • strripos() - 计算指定字符串在目标字符串中最后一次出现的位置(不区分大小写)
  • strstr() - 查找字符串的首次出现
  • strpbrk() - 在字符串中查找一组字符的任何一个字符
  • substr() - 返回字符串的子串
  • preg_match() - 执行匹配正则表达式

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在线手册:中文 英文

38位用户评论

[#1] ▲0▼ sunmacet@gmail.com [50%] (2020-11-23 10:14:30)

To check that a substring is present. Confusing check if position is not false: if ( strpos ( $haystack , $needle ) !== FALSE ) Logical check if there is position: if ( is_int ( strpos ( $haystack , $needle ) ) )

[#2] ▲0▼ ds@kala-it.de [50%] (2020-01-03 09:35:55)

Note this code example below in PHP 7.3 <?php
$str 
"17,25";

if(
FALSE !== strpos($str25)){
    echo 
"25 is inside of str";
} else {
    echo 
"25 is NOT inside of str";
}
?>
Will output "25 is NOT inside of str" and will throw out a deprication message, that non string needles will be interpreted as strings in the future. This just gave me some headache since the value I am checking against comes from the database as an integer.

[#3] ▲-5▼ hu60.cn@gmail.com [14%] (2019-06-09 13:25:42)

A more accurate imitation of the PHP function session_start(). Function my_session_start() does something similar to session_start() that has the default configure, and the session files generated by the two are binary compatible. The code may help people increase their understanding of the principles of the PHP session. <?php
error_reporting
(E_ALL);
ini_set('display_errors'true);
ini_set('session.save_path'__DIR__);

my_session_start();

echo 
'<p>session id: '.my_session_id().'</p>';

echo 
'<code><pre>';
var_dump($_SESSION);
echo 
'</pre></code>';

$now date('H:i:s');
if (isset(
$_SESSION['last_visit_time'])) {
  echo 
'<p>Last Visit Time: '.$_SESSION['last_visit_time'].'</p>';
}
echo 
'<p>Current Time: '.$now.'</p>';

$_SESSION['last_visit_time'] = $now;

function 
my_session_start() {
  global 
$phpsessid$sessfile;
 
  if (!isset(
$_COOKIE['PHPSESSID']) || empty($_COOKIE['PHPSESSID'])) {
    
$phpsessid my_base32_encode(my_random_bytes(16));
    
setcookie('PHPSESSID'$phpsessidini_get('session.cookie_lifetime'), ini_get('session.cookie_path'), ini_get('session.cookie_domain'), ini_get('session.cookie_secure'), ini_get('session.cookie_httponly'));
  } else {
    
$phpsessid substr(preg_replace('/[^a-z0-9]/'''$_COOKIE['PHPSESSID']), 026);
  }
 
  
$sessfile ini_get('session.save_path').'/sess_'.$phpsessid;
  if (
is_file($sessfile)) {
    
$_SESSION my_unserialize(file_get_contents($sessfile));
  } else {
    
$_SESSION = array();
  }
  
register_shutdown_function('my_session_save');
}

function 
my_session_save() {
  global 
$sessfile;
 
  
file_put_contents($sessfilemy_serialize($_SESSION));
}

function 
my_session_id() {
  global 
$phpsessid;
  return 
$phpsessid;
}

function 
my_serialize($data) {
  
$text '';
  foreach (
$data as $k=>$v) {
    
// key cannot contains '|'
    
if (strpos($k'|') !== false) {
      continue;
    }
    
$text.=$k.'|'.serialize($v)."\n";
  }
  return 
$text;
}

function 
my_unserialize($text) {
  
$data = [];
  
$text explode("\n"$text);
  foreach (
$text as $line) {
    
$pos strpos($line'|');
    if (
$pos === false) {
      continue;
    }
    
$data[substr($line0$pos)] = unserialize(substr($line$pos 1));
  }
  return 
$data;
}

function 
my_random_bytes($length) {
  if (
function_exists('random_bytes')) {
      return 
random_bytes($length);
  }
  
$randomString '';
  for (
$i 0$i $length$i++) { 
      
$randomString .= chr(rand(0255));
  } 
  return 
$randomString;
}

function 
my_base32_encode($input) {
  
$BASE32_ALPHABET 'abcdefghijklmnopqrstuvwxyz234567';
  
$output '';
  
$v 0;
  
$vbits 0;
  for (
$i 0$j strlen($input); $i $j$i++) {
    
$v <<= 8;
    
$v += ord($input[$i]);
    
$vbits += 8;
    while (
$vbits >= 5) {
      
$vbits -= 5;
      
$output .= $BASE32_ALPHABET[$v >> $vbits];
      
$v &= ((<< $vbits) - 1);
    }
  }
  if (
$vbits 0) {
    
$v <<= ($vbits);
    
$output .= $BASE32_ALPHABET[$v];
  }
  return 
$output;
}

[#4] ▲0▼ jean [50%] (2019-03-05 17:50:13)

When a value can be of "unknow" type, I find this conversion trick usefull and more readable than a formal casting (for php7.3+): <?php
$time 
time();
$string 'This is a test: ' $time;
echo (
strpos($string$time) !== false 'found' 'not found');
echo (
strpos($string"$time") !== false 'found' 'not found');
?>

[#5] ▲-1▼ amolocaleb@gmail.com [33%] (2018-09-06 15:00:13)

Note that strpos() is case sensitive,so when doing a case insensitive search,use stripos() instead..If the latter is not available,subject the string to strlower() first,otherwise you may end up in this situation.. <?php
//say we are matching url routes and calling access control middleware depending on the route

$registered_route '/admin' ;
//now suppose we want to call the authorization middleware before accessing the admin route 
if(strpos($path->url(),$registered_route) === 0){
     
$middleware->call('Auth','login');
}
?>
and the auth middleware is as follows <?php
class Auth{

function 
login(){
   if(!
loggedIn()){
       return 
redirect("path/to/login.php");
}
return 
true;
}
}

//Now suppose:
$user_url '/admin';
//this will go to the Auth middleware for checks and redirect accordingly

//But:
$user_url '/Admin';
//this will make the strpos function return false since the 'A' in admin is upper case and user will be taken directly to admin dashboard authentication and authorization notwithstanding
?>
Simple fixes: <?php
//use stripos() as from php 5
if(stripos($path->url(),$registered_route) === 0){
     
$middleware->call('Auth','login');
}
//for those with php 4
if(stripos(strtolower($path->url()),$registered_route) === 0){
     
$middleware->call('Auth','login');
}
//make sure the $registered_route is also lowercase.Or JUST UPGRADE to PHP 5>

[#6] ▲-1▼ msegit post pl [40%] (2018-07-18 00:41:47)

This might be useful, I often use for parsing file paths etc. (Some examples inside https://gist.github.com/msegu/bf7160257037ec3e301e7e9c8b05b00a ) <?php
/**
* Function 'strpos_' finds the position of the first or last occurrence of a substring in a string, ignoring number of characters
*
* Function 'strpos_' is similar to 'str[r]pos()', except:
* 1. fourth (last, optional) param tells, what to return if str[r]pos()===false
* 2. third (optional) param $offset tells as of str[r]pos(), BUT if negative (<0) search starts -$offset characters counted from the end AND skips (ignore!, not as 'strpos' and 'strrpos') -$offset-1 characters from the end AND search backwards
*
* @param string $haystack Where to search
* @param string $needle What to find
* @param int $offset (optional) Number of characters to skip from the beginning (if 0, >0) or from the end (if <0) of $haystack
* @param mixed $resultIfFalse (optional) Result, if not found
*    Example:
*    positive $offset - like strpos:
*        strpos_('abcaba','ab',1)==strpos('abcaba','ab',1)==3, strpos('abcaba','ab',4)===false, strpos_('abcaba','ab',4,'Not found')==='Not found'
*    negative $offset - similar to strrpos:
*        strpos_('abcaba','ab',-1)==strpos('abcaba','ab',-1)==3, strrpos('abcaba','ab',-3)==3 BUT strpos_('abcaba','ab',-3)===0 (omits 2 characters from the end, because -2-1=-3, means search in 'abca'!)
*
* @result int $offset Returns offset (or false), or $resultIfFalse
*/
function strpos_($haystack$needle$offset 0$resultIfFalse false) {
    
$haystack=((string)$haystack);    // (string) to avoid errors with int, float...
    
$needle=((string)$needle);
    if (
$offset>=0) {
        
$offset=strpos($haystack$needle$offset);
        return ((
$offset===false)? $resultIfFalse $offset);
    } else {
        
$haystack=strrev($haystack);
        
$needle=strrev($needle);
        
$offset=strpos($haystack,$needle,-$offset-1);
        return ((
$offset===false)? $resultIfFalse strlen($haystack)-$offset-strlen($needle));
    }
}
?>

[#7] ▲0▼ marvin_elia@web.de [50%] (2018-04-19 09:36:46)

Find position of nth occurrence of a string: function strpos_occurrence(string $string, string $needle, int $occurrence, int $offset = null) { if((0 < $occurrence) && ($length = strlen($needle))) { do { } while ((false !== $offset = strpos($string, $needle, $offset)) && --$occurrence && ($offset += $length)); return $offset; } return false; }

[#8] ▲7▼ greg@spotx.net [67%] (2017-11-27 00:48:15)

Warning: this is not unicode safe strpos($word,'?') in e?ez-> 1 strpos($word,'?') in è?ent-> 2

[#9] ▲1▼ lhenry [55%] (2017-10-03 09:34:01)

note that strpos( "8 june 1970" , 1970 ) returns FALSE.. add quotes to the needle

[#10] ▲0▼ eef.vreeland@gmail.com [50%] (2017-04-22 13:16:29)

To prevent others from staring at the text, note that the wording of the 'Return Values' section is ambiguous. Let's say you have a string $myString containing 50 'a's except on position 3 and 43, they contain 'b'. And for this moment, forget that counting starts from 0. strpos($myString, 'b', 40) returns 43, great. And now the text: "Returns the position of where the needle exists relative to the beginning of the haystack string (independent of offset)." So it doesn't really matter what offset I specify; I'll get the REAL position of the first occurrence in return, which is 3? ... no ... "independent of offset" means, you will get the REAL positions, thus, not relative to your starting point (offset). Substract your offset from strpos()'s answer, then you have the position relative to YOUR offset.

[#11] ▲6▼ jexy.ru@gmail.com [57%] (2017-01-23 08:29:48)

Docs are missing that WARNING is issued if needle is '' (empty string). In case of empty haystack it just return false: For example: <?php
var_dump
(strpos('foo'''));

var_dump(strpos('''foo'));

var_dump(strpos(''''));
?>
will output: Warning: strpos(): Empty needle in /in/lADCh on line 3 bool(false) bool(false) Warning: strpos(): Empty needle in /in/lADCh on line 7 bool(false) Note also that warning text may differ depending on php version, see https://3v4l.org/lADCh

[#12] ▲2▼ m.m.j.kronenburg [57%] (2016-09-06 22:56:00)

<?php

/**
 * Find the position of the first occurrence of one or more substrings in a 
 * string.
 * 
 * This function is simulair to function strpos() except that it allows to 
 * search for multiple needles at once.
 *
 * @param string $haystack    The string to search in.
 * @param mixed $needles      Array containing needles or string containing 
 *                            needle.
 * @param integer $offset     If specified, search will start this number of 
 *                            characters counted from the beginning of the 
 *                            string.
 * @param boolean $last       If TRUE then the farthest position from the start 
 *                            of one of the needles is returned.
 *                            If FALSE then the smallest position from start of 
 *                            one of the needles is returned.
 **/
function mstrpos($haystack$needles$offset 0$last false)
{
  if(!
is_array($needles)) { $needles = array($needles); }
  
$found false;
  foreach(
$needles as $needle)
  {
    
$position strpos($haystack, (string)$needle$offset);
    if(
$position === false) { continue; }
    
$exp $last ? ($found === false || $position $found) : 
      (
$found === false || $position $found);
    if(
$exp) { $found $position; }
  }
  return 
$found;
}

/**
 * Find the position of the first (partially) occurrence of a substring in a 
 * string.
 * 
 * This function is simulair to function strpos() except that it wil return a 
 * position when the substring is partially located at the end of the string.
 *
 * @param string $haystack    The string to search in.
 * @param mixed $needle       The needle to search for.
 * @param integer $offset     If specified, search will start this number of 
 *                            characters counted from the beginning of the 
 *                            string.
 **/
function pstrpos($haystack$needle$offset 0)
{
  
$position strpos($haystack$needle$offset);
  if(
$position !== false) { return $position; }
  
  for(
$i strlen($needle); $i 0$i--)
  {
    if(
substr($needle0$i) == substr($haystack, -$i))
    { return 
strlen($haystack) - $i; }
  }
  return 
false;
}

/**
 * Find the position of the first (partially) occurrence of one or more 
 * substrings in a string.
 * 
 * This function is simulair to function strpos() except that it allows to 
 * search for multiple needles at once and it wil return a position when one of
 * the substrings is partially located at the end of the string.
 *
 * @param string $haystack    The string to search in.
 * @param mixed $needles      Array containing needles or string containing 
 *                            needle.
 * @param integer $offset     If specified, search will start this number of 
 *                            characters counted from the beginning of the 
 *                            string.
 * @param boolean $last       If TRUE then the farthest position from the start 
 *                            of one of the needles is returned.
 *                            If FALSE then the smallest position from start of 
 *                            one of the needles is returned.
 **/
function mpstrpos($haystack$needles$offset 0$last false)
{
  if(!
is_array($needles)) { $needles = array($needles); }
  
$found false;
  foreach(
$needles as $needle)
  {
    
$position pstrpos($haystack, (string)$needle$offset);
    if(
$position === false) { continue; }
    
$exp $last ? ($found === false || $position $found) : 
      (
$found === false || $position $found);
    if(
$exp) { $found $position; }
  }
  return 
$found;
}

?>

[#13] ▲24▼ fabio@naoimporta.com [66%] (2016-02-25 16:58:49)

It is interesting to be aware of the behavior when the treatment of strings with characters using different encodings. <?php
# Works like expected. There is no accent
var_dump(strpos("Fabio"'b'));
#int(2)

# The "á" letter is occupying two positions
var_dump(strpos("Fábio"'b')) ;
#int(3)

# Now, encoding the string "Fábio" to utf8, we get some "unexpected" outputs. Every letter that is no in regular ASCII table, will use 4 positions(bytes). The starting point remains like before.
# We cant find the characted, because the haystack string is now encoded.
var_dump(strpos(utf8_encode("Fábio"), 'á'));
#bool(false)

# To get the expected result, we need to encode the needle too
var_dump(strpos(utf8_encode("Fábio"), utf8_encode('á')));
#int(1) 

# And, like said before, "á" occupies 4 positions(bytes)
var_dump(strpos(utf8_encode("Fábio"), 'b'));
#int(5)

[#14] ▲0▼ lairdshaw@yahoo.com.au [50%] (2015-04-03 18:02:45)

<?php
/*
 * A strpos variant that accepts an array of $needles - or just a string,
 * so that it can be used as a drop-in replacement for the standard strpos,
 * and in which case it simply wraps around strpos and stripos so as not
 * to reduce performance.
 *
 * The "m" in "strposm" indicates that it accepts *m*ultiple needles.
 *
 * Finds the earliest match of *all* needles. Returns the position of this match
 * or false if none found, as does the standard strpos. Optionally also returns
 * via $match either the matching needle as a string (by default) or the index
 * into $needles of the matching needle (if the STRPOSM_MATCH_AS_INDEX flag is
 * set).
 *
 * Case-insensitive searching can be specified via the STRPOSM_CI flag.
 * Note that for case-insensitive searches, if the STRPOSM_MATCH_AS_INDEX is
 * not set, then $match will be in the haystack's case, not the needle's case,
 * unless the STRPOSM_NC flag is also set.
 *
 * Flags can be combined using the bitwise or operator,
 * e.g. $flags = STRPOSM_CI|STRPOSM_NC
 */
define('STRPOSM_CI'            1); // CI => "case insensitive".
define('STRPOSM_NC'            2); // NC => "needle case".
define('STRPOSM_MATCH_AS_INDEX'4);
function 
strposm($haystack$needles$offset 0, &$match null$flags 0) {
    
// In the special case where $needles is not an array, simply wrap
    // strpos and stripos for performance reasons.
    
if (!is_array($needles)) {
        
$func $flags STRPOSM_CI 'stripos' 'strpos';
        
$pos $func($haystack$needles$offset);
        if (
$pos !== false) {
            
$match = (($flags STRPOSM_MATCH_AS_INDEX)
                      ? 
0
                      
: (($flags STRPOSM_NC)
                         ? 
$needles
                         
substr($haystack$posstrlen($needles))
                        )
                      );
            return 
$pos;
        } else    goto 
strposm_no_match;
    }

    
// $needles is an array. Proceed appropriately, initially by...
    // ...escaping regular expression meta characters in the needles.
    
$needles_esc array_map('preg_quote'$needles);
    
// If either of the "needle case" or "match as index" flags are set,
    // then create a sub-match for each escaped needle by enclosing it in
    // parentheses. We use these later to find the index of the matching
    // needle.
    
if (($flags STRPOSM_NC) || ($flags STRPOSM_MATCH_AS_INDEX)) {
        
$needles_esc array_map(
            function(
$needle) {return '('.$needle.')';},
            
$needles_esc
        
);
    }
    
// Create the regular expression pattern to search for all needles.
    
$pattern '('.implode('|'$needles_esc).')';
    
// If the "case insensitive" flag is set, then modify the regular
    // expression with "i", meaning that the match is "caseless".
    
if ($flags STRPOSM_CI$pattern .= 'i';
    
// Find the first match, including its offset.
    
if (preg_match($pattern$haystack$matchesPREG_OFFSET_CAPTURE$offset)) {
        
// Pull the first entry, the overall match, out of the matches array.
        
$found array_shift($matches);
        
// If we need the index of the matching needle, then...
        
if (($flags STRPOSM_NC) || ($flags STRPOSM_MATCH_AS_INDEX)) {
            
// ...find the index of the sub-match that is identical
            // to the overall match that we just pulled out.
            // Because sub-matches are in the same order as needles,
            // this is also the index into $needles of the matching
            // needle.
            
$index array_search($found$matches);
        }
        
// If the "match as index" flag is set, then return in $match
        // the matching needle's index, otherwise...
        
$match = (($flags STRPOSM_MATCH_AS_INDEX)
          ? 
$index
          
// ...if the "needle case" flag is set, then index into
          // $needles using the previously-determined index to return
          // in $match the matching needle in needle case, otherwise...
          
: (($flags STRPOSM_NC)
             ? 
$needles[$index]
             
// ...by default, return in $match the matching needle in
             // haystack case.
             
$found[0]
          )
        );
        
// Return the captured offset.
        
return $found[1];
    }

strposm_no_match:
    
// Nothing matched. Set appropriate return values.
    
$match = ($flags STRPOSM_MATCH_AS_INDEX) ? false null;
    return 
false;
}
?>

[#15] ▲0▼ qrworld.net [50%] (2014-11-04 16:08:52)

I found a function in this post http://softontherocks.blogspot.com/2014/11/buscar-multiples-textos-en-un-texto-con.html that implements the search in both ways, case sensitive or case insensitive, depending on an input parameter. The function is: function getMultiPos($haystack, $needles, $sensitive=true, $offset=0){ foreach($needles as $needle) { $result[$needle] = ($sensitive) ? strpos($haystack, $needle, $offset) : stripos($haystack, $needle, $offset); } return $result; } It was very useful for me.

[#16] ▲5▼ ohcc@163.com [55%] (2014-06-27 10:52:27)

Be careful when the $haystack or $needle parameter is an integer. If you are not sure of its type, you should convert it into a string. <?php
    var_dump
(strpos(12345,1));//false
    
var_dump(strpos(12345,'1'));//0
    
var_dump(strpos('12345',1));//false
    
var_dump(strpos('12345','1'));//0
    
$a 12345;
    
$b 1;
    
var_dump(strpos(strval($a),strval($b)));//0
    
var_dump(strpos((string)$a,(string)$b));//0    
?>

[#17] ▲-2▼ binodluitel@hotmail.com [38%] (2014-03-27 16:26:10)

This function will return 0 if the string that you are searching matches i.e. needle matches the haystack {code} echo strpos('bla', 'bla'); {code} Output: 0

[#18] ▲0▼ lurvik [50%] (2013-12-16 19:02:43)

Don't know if already posted this, but if I did this is an improvement. This function will check if a string contains a needle. It _will_ work with arrays and multidimensional arrays (I've tried with a > 16 dimensional array and had no problem). <?php
function str_contains($haystack$needles)
{
    
//If needles is an array
    
if(is_array($needles))
    {
        
//go trough all the elements
        
foreach($needles as $needle)
        {
            
//if the needle is also an array (ie needles is a multidimensional array)
            
if(is_array($needle))
            {
                
//call this function again
                
if(str_contains($haystack$needle))
                {
                    
//Will break out of loop and function.
                    
return true;
                }
                
                return 
false;
            }

            
//when the needle is NOT an array:
                //Check if haystack contains the needle, will ignore case and check for whole words only
            
elseif(preg_match("/\b$needle\b/i"$haystack) !== 0)
            {
                return 
true;
            }
        }
    }
    
//if $needles is not an array...
    
else
    {
        if(
preg_match("/\b$needles\b/i"$haystack) !== 0)
        {
            return 
true;
        }
    }

    return 
false;
}
?>

[#19] ▲2▼ anonymous [52%] (2013-02-18 21:55:53)

The most straightforward way to prevent this function from returning 0 is: strpos('x'.$haystack, $needle, 1) The 'x' is simply a garbage character which is only there to move everything 1 position. The number 1 is there to make sure that this 'x' is ignored in the search. This way, if $haystack starts with $needle, then the function returns 1 (rather than 0).

[#20] ▲15▼ mtroy.student@gmail.com [60%] (2012-04-25 16:46:52)

when you want to know how much of substring occurrences, you'll use "substr_count". But, retrieve their positions, will be harder. So, you can do it by starting with the last occurrence : function strpos_r($haystack, $needle) { if(strlen($needle) > strlen($haystack)) trigger_error(sprintf("%s: length of argument 2 must be <= argument 1", __FUNCTION__), E_USER_WARNING); $seeks = array(); while($seek = strrpos($haystack, $needle)) { array_push($seeks, $seek); $haystack = substr($haystack, 0, $seek); } return $seeks; } it will return an array of all occurrences a the substring in the string Example : $test = "this is a test for testing a test function... blah blah"; var_dump(strpos_r($test, "test")); // output array(3) { [0]=> int(29) [1]=> int(19) [2]=> int(10) } Paul-antoine Malézieux.

[#21] ▲21▼ martijn@martijnfrazer.nl [69%] (2012-02-25 15:58:20)

This is a function I wrote to find all occurrences of a string, using strpos recursively. <?php
function strpos_recursive($haystack$needle$offset 0, &$results = array()) {                
    
$offset strpos($haystack$needle$offset);
    if(
$offset === false) {
        return 
$results;            
    } else {
        
$results[] = $offset;
        return 
strpos_recursive($haystack$needle, ($offset 1), $results);
    }
}
?>
This is how you use it: <?php
$string 
'This is some string';
$search 'a';
$found strpos_recursive($string$search);

if(
$found) {
    foreach(
$found as $pos) {
        echo 
'Found "'.$search.'" in string "'.$string.'" at position <b>'.$pos.'</b><br />';
    }    
} else {
    echo 
'"'.$search.'" not found in "'.$string.'"';
}
?>

[#22] ▲21▼ rjeggens@ijskoud.org [62%] (2012-01-24 07:38:03)

I lost an hour before I noticed that strpos only returns FALSE as a boolean, never TRUE.. This means that strpos() !== false is a different beast then: strpos() === true since the latter will never be true. After I found out, The warning in the documentation made a lot more sense.

[#23] ▲-1▼ gjh42 - simonokewode@hotmail.com [48%] (2011-11-07 19:59:18)

A pair of functions to replace every nth occurrence of a string with another string, starting at any position in the haystack. The first works on a string and the second works on a single-level array of strings, treating it as a single string for replacement purposes (any needles split over two array elements are ignored). Can be used for formatting dynamically-generated HTML output without touching the original generator: e.g. add a newLine class tag to every third item in a floated list, starting with the fourth item. <?php
/* String Replace at Intervals   by Glenn Herbert (gjh42)    2010-12-17
 */
 
//(basic locator by someone else - name unknown)
//strnposr() - Find the position of nth needle in haystack.
function strnposr($haystack$needle$occurrence$pos 0) {
    return (
$occurrence<2)?strpos($haystack$needle$pos):strnposr($haystack,$needle,$occurrence-1,strpos($haystack$needle$pos) + 1);
}

//gjh42
//replace every nth occurrence of $needle with $repl, starting from any position
function str_replace_int($needle$repl$haystack$interval$first=1$pos=0) {
  if (
$pos >= strlen($haystack) or substr_count($haystack$needle$pos) < $first) return $haystack;
  
$firstpos strnposr($haystack$needle$first$pos);
  
$nl strlen($needle);
  
$qty floor(substr_count($haystack$needle$firstpos 1)/$interval);
  do { 
//in reverse order
    
$nextpos strnposr($haystack$needle, ($qty $interval) + 1$firstpos); 
    
$qty--;
    
$haystack substr_replace($haystack$repl$nextpos$nl);
  } while (
$nextpos $firstpos);
  return 
$haystack;
}
  
//$needle = string to find
  //$repl = string to replace needle
  //$haystack = string to do replacing in
  //$interval = number of needles in loop
  //$first=1 = first occurrence of needle to replace (defaults to first) 
  //$pos=0 = position in haystack string to start from (defaults to first) 
 
//replace every nth occurrence of $needle with $repl, starting from any position, in a single-level array
function arr_replace_int($needle$repl$arr$interval$first=1$pos=0$glue='|+|') {
  if (!
is_array($arr))  return $arr;
  foreach(
$arr as $key=>$value){
    if (
is_array($arr[$key])) return $arr;
  }
  
$haystack implode($glue$arr);
  
$haystack str_replace_int($needle$repl$haystack$interval$first$pos);
  
$tarr explode($glue$haystack);
  
$i 0;
  foreach(
$arr as $key=>$value){
    
$arr[$key] = $tarr[$i];
    
$i++;
  }
  return 
$arr;
}
?>
If $arr is not an array, or a multilevel array, it is returned unchanged.

[#24] ▲10▼ akarmenia@gmail.com [55%] (2011-03-05 04:44:26)

My version of strpos with needles as an array. Also allows for a string, or an array inside an array. <?php
function strpos_array($haystack$needles) {
    if ( 
is_array($needles) ) {
        foreach (
$needles as $str) {
            if ( 
is_array($str) ) {
                
$pos strpos_array($haystack$str);
            } else {
                
$pos strpos($haystack$str);
            }
            if (
$pos !== FALSE) {
                return 
$pos;
            }
        }
    } else {
        return 
strpos($haystack$needles);
    }
}

// Test
echo strpos_array('This is a test', array('test''drive')); // Output is 10

?>

[#25] ▲0▼ gambajaja@yahoo.com [50%] (2010-08-17 15:25:25)

<?php
$my_array 
= array ('100,101''200,201''300,301');
$check_me_in = array ('100','200','300','400');
foreach (
$check_me_in as $value_cmi){
    
$is_in=FALSE#asume that $check_me_in isn't in $my_array
    
foreach ($my_array as $value_my){
        
$pos strpos($value_my$value_cmi);
        if (
$pos===0)
            
$pos++;
        if (
$pos==TRUE){
            
$is_in=TRUE;
            
$value_my2=$value_my;
            }
    }
    if (
$is_in) echo "ID $value_cmi in \$check_me_in I found in value '$value_my2' \n";
}
?>
The above example will output ID 100 in $check_me_in I found in value '100,101' ID 200 in $check_me_in I found in value '200,201' ID 300 in $check_me_in I found in value '300,301'

[#26] ▲2▼ usulaco@gmail.com [57%] (2010-08-11 05:04:21)

Parse strings between two others in to array. <?php
function g($string,$start,$end){
     
preg_match_all('/' preg_quote($start'/') . '(.*?)'preg_quote($end'/').'/i'$string$m);
     
$out = array();

     foreach(
$m[1] as $key => $value){
       
$type explode('::',$value);
       if(
sizeof($type)>1){
          if(!
is_array($out[$type[0]]))
             
$out[$type[0]] = array();
          
$out[$type[0]][] = $type[1];
       } else {
          
$out[] = $value;
       }
     }
  return 
$out;
}
print_r(g('Sample text, [/text to extract/] Rest of sample text [/WEB::http://google.com/] bla bla bla. ','[/','/]'));
?>
results: Array ( [0] => text to extract [WEB] => Array ( [0] => http://google.com ) ) Can be helpfull to custom parsing :)

[#27] ▲1▼ achintya [51%] (2009-11-06 14:03:34)

A function I made to find the first occurrence of a particular needle not enclosed in quotes(single or double). Works for simple nesting (no backslashed nesting allowed). <?php
function strposq($haystack$needle$offset 0){
    
$len strlen($haystack);
    
$charlen strlen($needle);
    
$flag1 false;
    
$flag2 false;
    for(
$i $offset$i $len$i++){
        if(
substr($haystack$i1) == "'"){
            
$flag1 = !$flag1 && !$flag2 true false;
        }
        if(
substr($haystack$i1) == '"'){
            
$flag2 = !$flag1 && !$flag2 true false;
        }
        if(
substr($haystack$i$charlen) == $needle && !$flag1 && !$flag2){
            return 
$i;        
        }
    }
    return 
false;
}

echo 
strposq("he'llo'character;\"'som\"e;crap"";"); //16
?>

[#28] ▲0▼ yasindagli@gmail.com [50%] (2009-10-05 09:05:46)

This function finds postion of nth occurence of a letter starting from offset. <?php
function nth_position($str$letter$n$offset 0){
    
$str_arr str_split($str);
    
$letter_size array_count_values(str_split(substr($str$offset)));
    if( !isset(
$letter_size[$letter])){
        
trigger_error('letter "' $letter '" does not exist in ' $str ' after ' $offset '. position'E_USER_WARNING);
        return 
false;
    } else if(
$letter_size[$letter] < $n) {
        
trigger_error('letter "' $letter '" does not exist ' $n .' times in ' $str ' after ' $offset '. position'E_USER_WARNING);
        return 
false;
    }
    for(
$i $offset$x 0$count = (count($str_arr) - $offset); $i $count$x != $n$i++){
        if(
$str_arr[$i] == $letter){
            
$x++;
        }
    }
    return 
$i 1;
}

echo 
nth_position('foobarbaz''a'2); //7
echo nth_position('foobarbaz''b'14); //6
?>

[#29] ▲1▼ digitalpbk@gmail.com [51%] (2009-09-30 20:37:54)

This function raises a warning if the offset is not between 0 and the length of string: Warning: strpos(): Offset not contained in string in %s on line %d

[#30] ▲-1▼ ah.d@hotmail.com [48%] (2009-08-11 13:29:19)

A strpos modification to return an array of all the positions of a needle in the haystack <?php
function strallpos($haystack,$needle,$offset 0){
    
$result = array();
    for(
$i $offset$i<strlen($haystack); $i++){
        
$pos strpos($haystack,$needle,$i);
        if(
$pos !== FALSE){
            
$offset =  $pos;
            if(
$offset >= $i){
                
$i $offset;
                
$result[] = $offset;
            }
        }
    }
    return 
$result;
}
?>
example:- <?php
$haystack 
"ASD is trying to get out of the ASDs cube but the other ASDs told him that his behavior will destroy the ASDs world";

$needle "ASD";

print_r(strallpos($haystack,$needle));

//getting all the positions starting from a specified position

print_r(strallpos($haystack,$needle,34));
?>

[#31] ▲0▼ teddanzig@yahoo.com [50%] (2009-03-23 09:48:06)

routine to return -1 if there is no match for strpos <?php
//instr function to mimic vb instr fucntion
function InStr($haystack$needle)
{
    
$pos=strpos($haystack$needle);
    if (
$pos !== false)
    {
        return 
$pos;
    }
    else
    {
        return -
1;
    }
}
?>

[#32] ▲2▼ tim [54%] (2008-11-17 17:52:32)

If you would like to find all occurences of a needle inside a haystack you could use this function strposall($haystack,$needle);. It will return an array with all the strpos's. <?php
/**
 * strposall
 * 
 * Find all occurrences of a needle in a haystack
 *
 * @param string $haystack
 * @param string $needle
 * @return array or false
 */
function strposall($haystack,$needle){
    
    
$s=0;
    
$i=0;
    
    while (
is_integer($i)){
        
        
$i strpos($haystack,$needle,$s);
        
        if (
is_integer($i)) { 
            
$aStrPos[] = $i
            
$s $i+strlen($needle); 
        }
    }
    if (isset(
$aStrPos)) { 
        return 
$aStrPos
    } 
    else { 
        return 
false
    }
}
?>

[#33] ▲1▼ ilaymyhat-rem0ve@yahoo.com [51%] (2008-04-01 16:17:34)

This might be useful. <?php
class String{
    
    
//Look for a $needle in $haystack in any position
    
public static function contains(&$haystack, &$needle, &$offset)
    {
        
$result strpos($haystack$needle$offset);
        return 
$result !== FALSE;
    }
    
    
//intuitive implementation .. if not found returns -1.
    
public static function strpos(&$haystack, &$needle, &$offset)
    {
        
$result strpos($haystack$needle$offset);
        if (
$result === FALSE )
        {
            return -
1;
        }
        return 
$result;
    }
    
}
//String
?>

[#34] ▲190▼ suggested re-write for pink warning box [75%] (2008-01-11 15:45:32)

WARNING As strpos may return either FALSE (substring absent) or 0 (substring at start of string), strict versus loose equivalency operators must be used very carefully. To know that a substring is absent, you must use: === FALSE To know that a substring is present (in any position including 0), you can use either of: !== FALSE (recommended) > -1 (note: or greater than any negative number) To know that a substring is at the start of the string, you must use: === 0 To know that a substring is in any position other than the start, you can use any of: > 0 (recommended) != 0 (note: but not !== 0 which also equates to FALSE) != FALSE (disrecommended as highly confusing) Also note that you cannot compare a value of "" to the returned value of strpos. With a loose equivalence operator (== or !=) it will return results which don't distinguish between the substring's presence versus position. With a strict equivalence operator (=== or !==) it will always return false.

[#35] ▲0▼ user@nomail.com [50%] (2007-05-15 02:21:48)

This is a bit more useful when scanning a large string for all occurances between 'tags'. <?php
function getStrsBetween($s,$s1,$s2=false,$offset=0) {
    
/*====================================================================
    Function to scan a string for items encapsulated within a pair of tags

    getStrsBetween(string, tag1, <tag2>, <offset>

    If no second tag is specified, then match between identical tags

    Returns an array indexed with the encapsulated text, which is in turn
    a sub-array, containing the position of each item.

    Notes:
    strpos($needle,$haystack,$offset)
    substr($string,$start,$length)

    ====================================================================*/

    
if( $s2 === false ) { $s2 $s1; }
    
$result = array();
    
$L1 strlen($s1);
    
$L2 strlen($s2);

    if( 
$L1==|| $L2==) {
        return 
false;
    }

    do {
        
$pos1 strpos($s,$s1,$offset);

        if( 
$pos1 !== false ) {
            
$pos1 += $L1;

            
$pos2 strpos($s,$s2,$pos1);

            if( 
$pos2 !== false ) {
                
$key_len $pos2 $pos1;

                
$this_key substr($s,$pos1,$key_len);

                if( !
array_key_exists($this_key,$result) ) {
                    
$result[$this_key] = array();
                }

                
$result[$this_key][] = $pos1;

                
$offset $pos2 $L2;
            } else {
                
$pos1 false;
            }
        }
    } while(
$pos1 !== false );

    return 
$result;
}
?>

[#36] ▲1▼ spinicrus@gmail.com [52%] (2006-10-14 10:58:24)

if you want to get the position of a substring relative to a substring of your string, BUT in REVERSE way: <?php

function strpos_reverse_way($string,$charToFind,$relativeChar) {
    
//
    
$relativePos strpos($string,$relativeChar);
    
$searchPos $relativePos;
    
$searchChar '';
    
//
    
while ($searchChar != $charToFind) {
        
$newPos $searchPos-1;
        
$searchChar substr($string,$newPos,strlen($charToFind));
        
$searchPos $newPos;
    }
    
//
    
if (!empty($searchChar)) {
        
//
        
return $searchPos;
        return 
TRUE;
    }
    else {
        return 
FALSE;
    }
    
//
}

?>

[#37] ▲-1▼ philip [47%] (2004-08-25 15:52:25)

Many people look for in_string which does not exist in PHP, so, here's the most efficient form of in_string() (that works in both PHP 4/5) that I can think of: <?php
function in_string($needle$haystack$insensitive false) {
    if (
$insensitive) {
        return 
false !== stristr($haystack$needle);
    } else {
        return 
false !== strpos($haystack$needle);
    }
}
?>

[#38] ▲4▼ bishop [56%] (2004-04-21 15:38:36)

Code like this: <?php
if (strpos('this is a test''is') !== false) {
    echo 
"found it";
}
?>
gets repetitive, is not very self-explanatory, and most people handle it incorrectly anyway. Make your life easier: <?php
function str_contains($haystack$needle$ignoreCase false) {
    if (
$ignoreCase) {
        
$haystack strtolower($haystack);
        
$needle   strtolower($needle);
    }
    
$needlePos strpos($haystack$needle);
    return (
$needlePos === false false : ($needlePos+1));
}
?>
Then, you may do: <?php
// simplest use
if (str_contains('this is a test''is')) {
    echo 
"Found it";
}

// when you need the position, as well whether it's present
$needlePos str_contains('this is a test''is');
if (
$needlePos) {
    echo 
'Found it at position ' . ($needlePos-1);
}

// you may also ignore case
$needlePos str_contains('this is a test''IS'true);
if (
$needlePos) {
    echo 
'Found it at position ' . ($needlePos-1);
}
?>