The preg_replace() function is an inbuilt function in PHP that is used to perform a regular expression for search and replace the content.
Syntax:
preg_replace( $pattern, $replacement, $subject, $limit, $count )
Parameters: This function accepts five parameters as mentioned above and described below.
- $pattern: This parameter contains the string element which is used to search the content and it can be a string or array of strings.
- $replacement: It is a mandatory parameter that specifies the string or an array with strings to replace.
- $subject: The string or an array with strings to search and replace.
- $limit: This parameter specifies the maximum possible replacements for each pattern.
- $count: It is an optional parameter. This variable will be filled with the number of replacements done.
Return Value: This function returns an array if the subject parameter is an array, or a string otherwise. The below programs illustrate the preg_replace() function in PHP.
Program 1: The following program replaces string by using the regular expression parameter.
php
<?php// PHP program to illustrate // preg_replace function$string = 'November 01, 2018';$pattern = '/(\w+) (\d+), (\d+)/i';$replacement = '${1} 02, $3';// print output of functionecho preg_replace($pattern, $replacement, $string);?> |
Output:
November 02, 2018
Program 2 :
php
<?php// PHP program to illustrate // preg_replace function$subject = array('1', 'GFG', '2','Geeks', '3', 'GCET', 'Contribute', '4'); $pattern = array('/\d/', '/[a-z]/', '/[1a]/'); $replace = array('X:$0', 'Y:$0', 'Z:$0'); // Print Result return by functionecho "preg_replace returns\n";print_r(preg_replace($pattern, $replace, $subject)); ?> |
Output:
preg_replace returns
Array
(
[0] => X:Z:1
[1] => GFG
[2] => X:2
[3] => GY:eY:eY:kY:s
[4] => X:3
[5] => GCET
[6] => CY:oY:nY:tY:rY:iY:bY:uY:tY:e
[7] => X:4
)
Program 3:
php
<?php// PHP program to illustrate // preg_replace function$count = 0;// Display result after replace and count echo preg_replace(array('/\d/', '/\s/'), '*', 'Geeks 4 Geeks', -1, $count);echo "\n" . $count;?> |
Output:
Geeks***Geeks 3
Reference: http://php.net/manual/en/function.preg-replace.php
