Skip to main content

Perl-style regular expressions( preg_replace)


• preg_replace() - 
                            This Perl-syntax function is equivalent to the ereg_replace() function. This
function works by replacing all occurrences of the pattern searched with the replacement characters
and then returns the modified result. The fourth parameter is optional, but when a number is entered
it determines how many occurrences of the pattern searched will be replaced. If no number is entered,
all occurrences of the search pattern will be replaced.

<?php
$url = "MySQL http://www.mysql.com";
print preg_replace("/http:\/\/(.*)/","<a
href=\"\${0}\">\${0}</a>",
$url);
?>

The script above changes the http reference to be replaced with the HTML code required to create a
web link. The three components of this function include the pattern to search for ("/http:\/\/(.*)/"), the
replacement string ("<a href=\"\${0}\">\${0}</a>") and then finally the variable that is going to be
searched and replaced. The ${0} tells the preg_replace() function to repeat the complete matched
pattern (in this case http://www.mysql.com).
In addition to individual variables, the pattern and replacement components can also be arrays. The
function will cycle through each element of each array, making replacements as they are found.

<?php
$text = "The dog barks, the bear growls and the cat meows";
$adults = array("/dog/", "/bear/", "/cat/");
$children = array("puppy", "cub", "kitten")
print preg_replace($adults,$children, $text);
?>

Labels:

Comments

Post a Comment

Popular posts from this blog

PHP INTRODUCTION

                     PHP  (recursive acronym for  PHP: Hypertext Preprocessor ) is a widely-used open source general-purpose scripting language that is especially suited for web development and can be embedded into HTML. PHP stands for  P HP:  H ypertext  P reprocessor PHP is a server-side scripting language, like ASP PHP scripts are executed on the server PHP supports many databases (MySQL, Informix, Oracle, Sybase, Solid, PostgreSQL, Generic ODBC, etc.) PHP is an open source software PHP is free to download and use Why PHP? PHP runs on different platforms (Windows, Linux, Unix, etc.) PHP is compatible with almost all servers used today (Apache, IIS, etc.) PHP is FREE to download from the official PHP resource:  www.php.net PHP is easy to learn and runs efficiently on the server side What can PHP do? Anything. PHP is mainly focused on server-side scripting, so you can...
6 comments
Read more

Data Encryption

Data encryption is the process of scrambling stored or transmitted information so that it is unintelligible until it is unscrambled by the intended recipient. The intended recipient can then decode (or decrypt) the information. PHP offers multiple means to make this happen. However, none of these solutions are very effective without the applications running on secure servers and connections. The following are a list of the more common encryption functions in PHP: • md5() - MD5 is a third-party hash algorithm that PHP can use to create a digital fingerprint of a piece of data. It is next to impossible to (efficiently) recover the original text when a piece of data has been encrypted with the md5 hash algorithm. It is also vastly unlikely that any different text string will create an identical hash - a 'hash collision'. These properties make hashes ideally suited for storing an application's passwords because although an attacker may compromise a part of the system...
2 comments
Read more

Delimiting PHP Code

                           PHP was originally designed to be used in conjunction with a web server, and in the case of the LAMP architecture, the Apache Web Server.  PHP applications are designed embedding PHP scripts within a web page along with its HTML.  Unlike standard HTML pages which are sent directly from the web server to the end user, PHP files are first interpreted by the PHP application which then converts the PHP script into another form for display.  This process eliminates the end user from being able to see the original PHP script that was embedded in the HTML and provides  true interaction in HTML files.  This process is similar to proprietary applications such as ASP and Coldfusion; however, PHP is Open Source and cross- platform. PHP Tags             PHP scripts are distinguished from the HTML scripts by using delimiting characters ...
1 comment
Read more