Preg_replace string - php

Question

I am creating a username from the users Billing First Name and Billing Last Name.
This in in. WooCommerce, though I suppose the cms is irrelevant to my question.
The following characters should be removed:
! # # $ % ^ & * ( ) ~ ` , . : ' " ; ; > < ? / \ |
Any number should be removed
The string must be in lowercase
All spaces must be replaced with hyphen.
Below is what I tried:
if(isset($_POST['billing_first_name']))
$fn = $_POST['billing_first_name'];
$fn = iconv('utf-8', 'us-ascii//TRANSLIT', $fn);
$fn = preg_replace('/[^a-z0-9-]+/', '-', strtolower($fn));
$fn = preg_replace("/-+/", '-', $fn);
$fn = trim($fn, '-');
if(isset($_POST['billing_last_name']))
$ln = $_POST['billing_last_name'];
$ln = iconv('utf-8', 'us-ascii//TRANSLIT', $ln);
$ln = preg_replace('/[^a-z0-9-]+/', '-', strtolower($ln));
$ln = preg_replace("/-+/", '-', $ln);
$ln = trim($ln, '-');
Example:
fn = Liz & Noël;
ln = John-Evan’s 2nd;
echo $fn . '-' . $ln;
Expected Outcome:
liznoel-johnevansnd
Computed Outcome:
liz-no-eljohn-evan-s-2nd

Answer 1

You can use
<?php
$fn = 'Liz & Noël';
$ln = 'John-Evan’s 2nd';
function process( $str )
{
$str = iconv('utf-8', 'us-ascii//TRANSLIT', $str);
$str = strtolower($str);
return preg_replace('~[^A-Za-z]+~u', '', $str);
}
echo process($fn) . '-' . process($ln);
Note that preg_replace('~[^A-Za-z]+~u', '', $str); removes any char other than an ASCII letter from any Unicode string. Since the hyphen appears between the two name parts, you cannot replace with a hyphen, you need to create the string from two parts using concatenation.