PHP Preg_replace function Base and instance code

PHP Tutorial Preg_replace function Basics and Instance code
Preg_replace (mixed $pattern, mixed $replacement, mixed $subject [, int $limit =-1 [, int & $count]]) theme for matching search pattern, replace replace
/*
The pattern to search for. It can be a string or an array of strings.

The electronic modifier enables the Preg_replace function () to replace the treated, appropriately referenced as a parameter is the PHP tutorial code to be replaced. Hint: Make sure the permutation constitutes a valid PHP code string, otherwise PHP will complain about parsing errors in the containing Preg_replace function line ().

return value

The Preg_replace function () returns an array if the argument of the problem is an array or a string, otherwise.

If a match is found, a new problem is generated, otherwise the subject will return unchanged or null if an error occurs.
*/

Instance One

$string = ' April 15, 2003 ';
$pattern = '/(w+) (d+), (d+)/I ';
$replacement = ' ${1}1,$3 ';
Echo preg_replace ($pattern, $replacement, $string);//Instance Two

$string = ' The quick brown fox jumped over the lazy dog. '
$patterns = Array ();
$patterns [0] = '/quick/';
$patterns [1] = '/brown/';
$patterns [2] = '/fox/';
$replacements = Array ();
$replacements [2] = ' bear ';
$replacements [1] = ' black ';
$replacements [0] = ' slow ';
Echo preg_replace ($patterns, $replacements, $string);//through ksorting mode and substitution, we should get what we want.

Ksort ($patterns);
Ksort ($replacements);
Echo preg_replace ($patterns, $replacements, $string);//Replace several values

$patterns = Array ('/(19|20) (d{2})-(d{1,2})-(d{1,2})/',
'/^s*{(w+)}s*=/');
$replace = Array (' 3/4/12 ', ' $ = ');
Echo preg_replace ($patterns, $replace, ' {startdate} = 1999-5-27 ');//filter all HTML tags

Preg_replace ("/(</?) (w+) ([^>]*>) E ",
"' 1 '. Strtoupper (' 2 ')." 3 ' ",
$html _body);//filter All script codes

$user _agent = "mozilla/4.0" (compatible; MSIE 5.01; Windows NT 5.0) ";

$ch = Curl_init (); Initialize Curl handle
curl_setopt ($ch, Curlopt_url, $url); Set URL to post to
curl_setopt ($ch, Curlopt_failonerror, 1); Fail on errors
curl_setopt ($ch, curlopt_followlocation, 1); Allow redirects
curl_setopt ($ch, curlopt_returntransfer,1); Return into a variable
curl_setopt ($ch, Curlopt_port, 80); Set the port number
curl_setopt ($ch, Curlopt_timeout, 15); Times out 15s

curl_setopt ($ch, curlopt_useragent, $user _agent);

$document = curl_exec ($ch);

$search = Array (' @<script[^>]*?>.*?</script> @si ',//strip out JavaScript tutorial www.jzread.com
' @<style[^>]*?>.*?</style> @siu ',//strip style tags properly
' @<[/!] *? [^<>]*?> @si ',//strip out HTML tags
' @<! [ss]*?–[tnr]*>@ ',//strip multi-line comments including CDATA
'/s{2,}/',

);

$text = Preg_replace ($search, "n", Html_entity_decode ($document));

$pat [0] = "/^s+/";
$pat [2] = "/s+$/";
$rep [0] = "";
$rep [2] = "";

$text = Preg_replace ($pat, $rep, Trim ($text));

return $text;
}
/*
This function accepts a URL and returns a plain text version of the page. It uses Curl to retrieve web pages, a combination of regular expressions, to remove all unnecessary whitespace. This feature is even stripped of the form and script tags, which are ignored by PHP functions, such as using strip_tags (they strip the only tagged text, leaving the full text in the middle).

Regular expressions are divided into two phases to avoid deleting a single (also matched by s) carriage return, but all blank lines and multiple line breaks or spaces are still deleted, and the trimming operation takes place in 2 stages.
*/
?>