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String Filters

Each of these filters does precisely what their name implies and correspond to the behavior of a built-in php string handling function. For more information on a given filter, refer to the manual page for the corresponding function.

string.rot13 (since PHP 4.3.0) Use of this filter is equivalent to processing all stream data through the str_rot13() function.

Example #1 string.rot13

<?php
$fp 
fopen('php://output''w');
stream_filter_append($fp'string.rot13');
fwrite($fp"This is a test.\n");
/* Outputs:  Guvf vf n grfg.   */
?>

string.toupper (since PHP 5.0.0) Use of this filter is equivalent to processing all stream data through the strtoupper() function.

Example #2 string.toupper

<?php
$fp 
fopen('php://output''w');
stream_filter_append($fp'string.toupper');
fwrite($fp"This is a test.\n");
/* Outputs:  THIS IS A TEST.   */
?>

string.tolower (since PHP 5.0.0) Use of this filter is equivalent to processing all stream data through the strtolower() function.

Example #3 string.tolower

<?php
$fp 
fopen('php://output''w');
stream_filter_append($fp'string.tolower');
fwrite($fp"This is a test.\n");
/* Outputs:  this is a test.   */
?>

string.strip_tags (since PHP 5.0.0) Use of this filter is equivalent to processing all stream data through the strip_tags() function. It accepts parameters in one of two forms: Either as a string containing a list of tags similar to the second parameter of the strip_tags() function, or as an array of tag names.

Example #4 string.strip_tags

<?php
$fp 
fopen('php://output''w');
stream_filter_append($fp'string.strip_tags'STREAM_FILTER_WRITE"<b><i><u>");
fwrite($fp"<b>bolded text</b> enlarged to a <h1>level 1 heading</h1>\n");
fclose($fp);
/* Outputs:  <b>bolded text</b> enlarged to a level 1 heading   */

$fp fopen('php://output''w');
stream_filter_append($fp'string.strip_tags'STREAM_FILTER_WRITE, array('b','i','u'));
fwrite($fp"<b>bolded text</b> enlarged to a <h1>level 1 heading</h1>\n");
fclose($fp);
/* Outputs:  <b>bolded text</b> enlarged to a level 1 heading   */
?>

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