Htaccess    html   Php    javascript   Asp   css    maths  Past Questions  Practice Tests Online

preg replace callback function syntax tag tutorial 2013 Donate at flattr Flattr this





Alert! Connect with 10,000 Chating Online. Join Now

Php preg replace callback () function

Write your php code

 
<?php ?>

Php Result


Your code below



(PHP 4 >= 4.0.5, PHP 5)

preg_replace_callback -- Perform a regular expression search and replace using a callback

Syntax

mixed preg_replace_callback ( mixed pattern, callback callback, mixed subject [, int limit] )

The behavior of this function is almost identical to preg_replace(), except for the fact that instead of replacement parameter, one should specify a callback that will be called and passed an array of matched elements in the subject string. The callback should return the replacement string.

Example 1. preg_replace_callback() example

<?php
// this text was used in 2002
// we want to get this up to date for 2003
$text = "April fools day is 04/01/2002\n";
$text.= "Last christmas was 12/24/2001\n";
// the callback function
function next_year($matches)
{
  
// as usual: $matches[0] is the complete match
  // $matches[1] the match for the first subpattern
  // enclosed in '(...)' and so on
  
return $matches[1].($matches[2]+1);
}
echo
preg_replace_callback(
            
"|(\d{2}/\d{2}/)(\d{4})|",
            
"next_year",
            
$text);
// result is:
// April fools day is 04/01/2003
// Last christmas was 12/24/2002
?>

You'll often need the callback function for a preg_replace_callback() in just one place. In this case you can use create_function() to declare an anonymous function as callback within the call to preg_replace_callback(). By doing it this way you have all information for the call in one place and do not clutter the function namespace with a callback functions name not used anywhere else.

Example 2. preg_replace_callback() and create_function()

<?php
/* a unix-style command line filter to convert uppercase
* letters at the beginning of paragraphs to lowercase */
$fp = fopen("php://stdin", "r") or die("can't read stdin");
while (!
feof($fp)) {
    
$line = fgets($fp);
    
$line = preg_replace_callback(
        
'|<p>\s*\w|',
        
create_function(
            
// single quotes are essential here,
            // or alternative escape all $ as \$
            
'$matches',
            
'return strtolower($matches[0]);'
        
),
        
$line
    
);
    echo
$line;
}
fclose($fp);
?>

See also preg_replace(), create_function(), and information about the callback type.

Php preg replace callback Function syntax tag

preg replace callback php code on this is provided for your study purpose, it will guide you to know how create and design a website using php. use it to practice and train your self online



Php preg replace callback syntax tutorial

php tutorial guide and code design are for easy learning and programming. The code practice section provided at the top is for practising of this syntax. Use the code section up to practice your php programming online. Learning php is very easy, all you need is to use the examples on this site and practice them to perfect your skills.


Function index

Variables

Expressions

Operators

Control-Structures

Cookies

Array

Date & Time

Directory function

File

Image

Operators

Form data handling

Mathematics operators

Mail

Php Mysql

Network Functions

Strings

php tutorial guides,functions, classes, code examples and tags for creating simple dynamic site to mysql database driven sites
 
 
Htaccess    html   Php    javascript   Asp   css    maths  Past Questions  Practice Tests Online