PHP Hashtag系统

Question

I'm trying to set up a hashtag system in PHP, where if the user input contains a # next to a word, it will be replaced with a link.

For example:

$input = "mysql_real_escape_string($_POST['input'])";
$sql = "INSERT INTO table (input) VALUES ('$input')";
mysql_query($sql, $connect);
?>
<?php
mysql_select_db("database",$connect);
$sql = mysql_real_escape_string("SELECT * FROM input");
$myData = mysql_query($sql, $connect);
echo $myData;

where $myData says something like "Just went 80mph in a schoolzone #yolo"

I want it to echo out:

Just went 80mph in a schoolzone <a href="search?q=%23yolo">#yolo</a>

like on Twitter. I don't know how to set this up, but I assume preg_match() or str_replace() may be involved.

Answer 1

The regex you're looking for is #([^\s]+) which matches one or more characters after a hash until white-space occurs. This can then be used with a preg_replace to create a link.

E.g.

$output = preg_replace( "/#([^\s]+)/", "<a href=\"search?q=%23$1\">#$1</a>", $input );