How to alter PHP replace function?

Question

add_filter('wp_list_categories', 'myCatNoBrk', 10, 1);

function myCatNoBrk($OrgCat) {
       $CatNoBrk = preg_replace('/<br \/>/',',',$OrgCat);
       return $CatNoBrk;
    }

Hello, this is part of a wordpress function that would replace html breaks with commas. How could I alter this to also remove and add 'x' around each element?

in other words: The output code is something like

<a href="xxx">cat1</a><br>
<a href="xxx2">cat2</a><br>
and so on

I'd like to change this to show only ('cat1','cat2') for an array definition

example output:

<?php $grades_array = array('a+','a','a-','b+','b','b-','c+');?>

Answer 1

I am not 100% sure what you are trying to achieve, but here's a replacement function that lets you specify what you are putting in place of the break tags (<br />)

add_filter('wp_list_categories', 'myCatNoBrk', 10, 1);

function myCatNoBrk($OrgCat,$replacement = ',') {
       $CatNoBrk = preg_replace('/<br \/>/',$replacement,$OrgCat);
       return $CatNoBrk;
    }

UPDATE: try this

add_filter('wp_list_categories', 'myCatNoBrk', 10, 1);

  function myCatNoBrk($OrgCat,) {

       preg_match_all(' /(?<=^|>)[^><]+?(?=<|$)/',$OrgCat,$CatNoBrk,PREG_PATTERN_ORDER);
       return '(\''.implode('\',\'',$CatNoBrk).'\')';
    }