[FIXED] How to replace some special characters?

Issue

I have a PHP code that will connect to a database, select a table and then get data from it. In one of my colums (That named title), i have data looks like: Hello World - This/That is (Test) But i want to convert this to this: hello-world-this-that-is-test Because i want to use this kind of text in my page's URL.

I mean i need to

1. Remove spaces
2. Remove double or multiple dashes
3. Remove slash and backslash
4. Remove brackets like ( and )

and want to replace all of them with only one dash as i wrote above. in other word i want to delete all special characters and convert them to only one dash

Currently my code can remove space and double dashes, but it can't remove slashes and brackets. here is my code:

<?php 
 define('DBHOST','localhost');
 define('DBUSER','user');
 define('DBPASS','pass');
 define('DBNAME','name');

$db = mysqli_connect(DBHOST, DBUSER, DBPASS, DBNAME);
$db->set_charset('utf8mb4');
if(!$db){
 die( "Sorry! There seems to be a problem connecting to our database.");
}

$myFile = "sitemap.xml";
$fh = fopen($myFile, 'w') or die("can't open file"); 
$rss_txt = null;

$rss_txt .= '<?xml version="1.0" encoding="UTF-8"?>';
$rss_txt .= '<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9" xmlns:image="http://www.google.com/schemas/sitemap-image/1.1">';

$query = mysqli_query($db, "SELECT * FROM posts_articles ORDER BY post_id ASC");
while($values_query = mysqli_fetch_assoc($query)) {
    $rss_txt .= '<url>';
    $rss_txt .= '<loc>https://example.com/blogs/'.$values_query["post_id"].'/'.$var = preg_replace("/[\s-]+/", "-", $values_query["title"]).'</loc>';
    $rss_txt .= '<changefreq>weekly</changefreq>';
    $rss_txt .= '<priority>0.7</priority>';
    $rss_txt .= '</url>';
}

$rss_txt .= '</urlset>';

fwrite($fh, $rss_txt);
fclose($fh);

?>

OK. This part of my code have to get title '.$var = preg_replace("/[\s-]+/", "-", $values_query["title"]).' this code can remove space and multi dashes to only one dash. USEFUL! But if title column have brackets or slashes, it can't remove them and my code will fail.

I'm very very new to PHP and SQL so don't blame me. i have to start learning but after reading over 50 articles, i couldn't find anything useful to do what i want.

Solution

Here's a solution that uses three separate regular expressions to do successive transformations to the string:

<?php

$regex1 = "/[^0-9a-z\s]+/i";        // Search for everything that is not alphanumeric or whitespace
$regex2 = "/\s+/";                  // Search for whitespace
$regex3 = "/-+$/";                  // search for trailing dashes

$text = "Hello World - This/That is (Test)";

// replace in turn, non-alpha with space, one or more spaces with dash,
// one or more trailing dashes with nothing 
$text2 = preg_replace([$regex1, $regex2, $regex3],[' ','-',''], $text);

// Switch everything to lower case
$text2 = strtolower($text2);

echo $text2;       // hello-world-this-that-is-test

Demo:https://3v4l.org/Pe5hC

(The regex purists might be able to condense this further, but this is clear and easily modifiable)

Answered By - Tangentially Perpendicular

Answer Checked By - Terry (PHPFixing Volunteer)