asked on

preg_replace_callback with square brackets

Hi,

Having a problem creating a regular expression to find and replace variable text within square brackets.

My string may contain several strings, wrapped in square brackets. The strings will be in the format of:

[brand:12:linkText]

I need to search for the text inside the square brackets, pass it to a function, and then replace the text (including the square brackets) with the return value of the function.

The code below returns the following error:

Delimiter must not be alphanumeric or backslash

Help !

$string = "This is a [brand:7:linkText] and so is [category:14:My Category]";

$pattern = "\[[a-zA-Z0-9:]\]"; //this isn't working

echo preg_replace_callback($pattern, "createLinks", $string);

function createLinks($matches) {
	return "<a href='{$matches[0]}'>{$matches[0]}</a>";
}

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Terry Woods

Your pattern needs terminators:
$pattern = "/\[[a-zA-Z0-9:]\]/"; //this isn't working

Terry Woods

(by terminators I mean delimiters)

Dave Baldwin

Try this. You pattern needed a space to change the second item into a link.

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
 "http://www.w3.org/TR/html4/loose.dtd">

<html>
<head>
<title>preg_replace_callback with square brackets</title>
</head>
<body>
<h1>preg_replace_callback with square brackets</h1>
<?php 
error_reporting(E_ALL);
$string = "This is a [brand:7:linkText] and so is [category:14:My Category]";

$pattern = "#(\[[a-zA-Z0-9: ]+\]+)#"; //this isn't working
//$pattern = "#(\[)|(\])#"; //this isn't working

echo preg_replace_callback($pattern, "createLinks", $string);

function createLinks($matches) {
        return "<a href='".$matches[0]."'>".$matches[0]."</a>";
        //return "..";
}
?>
</body>
</html>

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ASKER CERTIFIED SOLUTION

Dave Baldwin

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See answer

Chris Stanyon

ASKER

Thanks guys for the quick response.

@TerryAtOpus - I'd already tried with the delimiters - similar to your answer, but no joy.

@DaveBaldwin - Spot on. Exactly what I was looking for. Your second example saves me that extra step in the function - removing the square brackets.

Dave Baldwin

Cool, thanks for the points.