formatter.php

<?php

// Callback function to format numbers with &nbsp;
function format_numbers_with_nbsp($content) {
    // Regular expression pattern to match numbers
    $pattern = '/\b(\d{1,3}(?:\d{3})*)\b/';

    // Replace matched numbers with formatted version
    $formatted_content = preg_replace_callback($pattern, 'add_nbsp_to_number', $content);

    return $formatted_content;
}
add_filter('the_content', 'format_numbers_with_nbsp');

// Callback function to add &nbsp; to numbers
function add_nbsp_to_number($matches) {
    $number = $matches[0];

    // Format the number by adding &nbsp;
    $formatted_number = number_format($number, 0, '', '&nbsp;');

    return $formatted_number;
}