PHP Tutorial - PHP strrpos() Function

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Definition

The strrpos() function finds the position of the last occurrence of a string inside another string (case-sensitive).

Syntax

PHP strrpos() Function has the following syntax.

Parameter

Return

PHP strrpos() Function returns the position of the last occurrence of a string inside another string, or FALSE if the string is not found.

Related functions

• strpos() - Finds the position of the first occurrence of a string inside another string (case-sensitive)
• stripos() - Finds the position of the first occurrence of a string inside another string (case-insensitive)
• strripos() - Finds the position of the last occurrence of a string inside another string (case-insensitive)

Example 1

Find the position of the last occurrence of "php" inside the string:

<?php
echo strrpos("php, from java2s.com!","php");

$myString = "Hello, world!"; 
echo strpos( $myString, "o" ) . "\n";  // Displays '4' 
echo strrpos( $myString, "o" ) . "\n"; // Displays '8'   
?>

The code above generates the following result.

Example

When the searched text occurs at the start of the string. In this case, strpos() returns 0 (the index of the first character of the found text), but it's easy to mistake this for a return value of false if you're not careful.

For example, the following code will incorrectly display "Not found" :

<?PHP
   $myString = "Hello, world!"; 
   if ( !strrpos( $myString, "Hel" ) ) {
      echo "Not found";   
   }   
?>

So you need to test explicitly for a false return value, if that's what you're checking for.

The following code works correctly:

<?PHP
   $myString = "Hello, world!"; 
   if ( strrpos( $myString, "Hel" ) === false ){
       echo "Not found";   
   }
?>

Example 2

The following code shows how to get value from a line using strpos and substr.

<?php
   $substr = "index.html";

    $log = <<< logfile
    192.168.1.11:/www/htdocs/index.html:[2010/02/10:20:36:50]
    192.168.1.13:/www/htdocs/about.html:[2010/02/11:04:15:23]
    192.168.1.15:/www/htdocs/index.html:[2010/02/15:17:25]
logfile;

   // what is first occurrence of the time $substr in log?
   $pos = strpos($log, $substr);

   // Find the numerical position of the end of the line
   $pos2 = strpos($log,"\n",$pos);

   // Calculate the beginning of the timestamp
   $pos = $pos + strlen($substr) + 1;

   // Retrieve the timestamp
   $timestamp = substr($log,$pos,$pos2-$pos);

   echo "The file $substr was first accessed on: $timestamp";
?>

The code above generates the following result.

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