PHP/String/strrpos

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

   <source lang="html4strict">

<?

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

?>

 </source>
   
  

Finding a substring with strpos()

   <source lang="html4strict">

<?php if (strpos($_POST["email"], "@") === false) {

   print "There was no @ in the e-mail address!";
}

?>

 </source>
   
  

Finding the Position of a Substring with strpos()

   <source lang="html4strict">

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

 print "hello mz";

} ?>

 </source>
   
  

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

   <source lang="html4strict">

<?

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

?>

 </source>
   
  

Return String found at position 22

   <source lang="html4strict">

<?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";

?>

 </source>
   
  

strpos

   <source lang="html4strict">

<?php

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

?>

 </source>
   
  

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

   <source lang="html4strict">

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; ?>

 </source>
   
  

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

   <source lang="html4strict">

<?

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

?>

 </source>
   
  

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

   <source lang="html4strict">

Its syntax is: int strrpos (string string, char character) <?

 print strrpos("asdf","d");

?>

 </source>
   
  

strrpos.php

   <source lang="html4strict">

<?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;

?>

 </source>
   
  

Using several functions together to extract a portion of a string

   <source lang="html4strict">

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

 </source>
   
  

Using String Matching vs. Pattern Matching

   <source lang="html4strict">

<?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"; 

} ?>

 </source>