PHP/String/strrpos

A third parameter to strpos( ) that allows us to specify where to start searching from

 
<?
    $string = "This is a strpos( ) test";
    $pos = strpos($string, "i", 3);
    if ($pos =  == false) {
            print "Not found\n";
    } else {
            print "Found at $pos!\n";
    }
?>

Finding a substring with strpos()

 
<?php
if (strpos($_POST["email"], "@") === false) {
    print "There was no @ in the e-mail address!";
 }
?>

Finding the Position of a Substring with strpos()

 
<?php
$membership = "asdfasdf";
if ( strpos($membership, "mz") === 0 ) {
  print "hello mz";
}
?>

int strpos ( string haystack, mixed needle [, int offset] ) returns the index of the beginning of a substring"s first occurrence within a string

 
<?
    $string = "This is a strpos( ) test";
    print strpos($string, "s") . "\n";
?>

Return String found at position 22

 
<?php
    $haystack = "this is a test. this is a test. this is a test";
     $pos = strpos ($haystack, "bottle");
    if ($pos === false)
      echo "String not found\n";
    else
      echo "String found at position $pos\n";
?>

strpos

 
<?php
   $substr = "index.html";
   $log = "192.168.1.11:/www/htdocs/index.html:";
   $pos = strpos($log, $substr);
   echo "$pos";
?>

strpos() function finds the position of the first occurrence in string.

 
Its syntax is: int strpos (string string, string occurrence [, int offset])
offset specifies the position at which to begin the search. 
<?
$log = "1999-01-31";
$pos = strpos($log, "1999");
print $pos;
?>

strpos( ) will return false (as opposed to -1)

 
<?
    $string = "This is a strpos( ) test";
    $pos = strpos($string, "This");
    if ($pos =  == false) {
            print "Not found\n";
    } else {
            print "Found!\n";
    }
?>

strrpos() function locates the last occurrence of character in string.

 
Its syntax is: int strrpos (string string, char character)
<?
  print strrpos("asdf","d");
?>

strrpos.php

 
<?php
   $limit = 100;
$summary = <<< summary
this is a test. this is a test. this is a test. this is a test. this is a test. this is a test.
this is a test. this is a test. this is a test. this is a test. this is a test. this is a test.
this is a test. this is a test. this is a test. this is a test. this is a test. this is a test.
summary;
   if (strlen($summary) > $limit) 
      $summary = substr($summary, 0, strrpos(substr($summary, 0, $limit), " ")) . "...";
   echo $summary;
?>

Using several functions together to extract a portion of a string

 
<?php
$test_string="testing testing Username:Michele Bond";
$position=strpos($test_string,"Username:");
$start=$position+strlen("Username:");
echo "$test_string<br />";
echo "$position<br />";
echo substr($test_string,$start);
?>

Using String Matching vs. Pattern Matching

 
<?php 
$value = "my username"; 
if (strcmp($value, "user") == 0) { 
    echo "Found match in "" . $value . "" using strcmp.\n"; 
} else { 
    echo "Didn"t find match in "" . $value . "" using strcmp.\n"; 
} 
if (!(strrpos($value,"user") ==="false)) {
    echo "Found match in "" . $value . "" using strrpos.\n"; 
} else { 
    echo "Didn"t find match in "" . $value . "" using strrpos.\n"; 
} 
if (ereg("\<user\>", $value)) { 
    echo "Found match in "" . $value . "" using ereg.\n"; 
} else { 
    echo "Didn"t find match in "" . $value . "" using ereg.\n"; 
} 
?>