How can I default to all WordPress roles when parameter is not included in shortcode?

I am trying to set up a generic shortcode in WordPress with parameters for user meta key, meta value and roles that will count the total number of profiles that include certain values. So far I have made it work with one single role with the following code and shortcode:

[profilecounts metakey="Market" metavalue="149" userrole="franchisee_nm"]

add_shortcode('profilecounts', 'profile_counts');
function profile_counts($atts) { 
     $metakey = shortcode_atts( array('metakey' => 'None'), $atts );
     $metavalue = shortcode_atts( array('metavalue' => 'None'), $atts );
     $userrole = shortcode_atts( array('userrole' => 'avail_roles'), $atts );
return count( get_users(array('meta_key' => $metakey['metakey'], 'meta_value' => $metavalue['metavalue'], 'role' => $userrole['userrole'], ) ) );
} 

My issue is that I can’t get it to work with multiple roles and/or make it default to all roles.

I want to use the following to count multiple roles (or something of the sort):

[profilecounts metakey="Market" metavalue="149" userrole="franchisee_nm,franchisee_co"]

And I want to use the following to count all roles (or something of the sort):

[profilecounts metakey="Market" metavalue="149"]

EDIT: Okay, I figured a way around doing multiple roles using a second shortcode without the role parameter for now, but if someone can help me do what I’m trying to do, that would be great. Thanks in advance.

[profilecounts_conm metakey="Market" metavalue="149"]

add_shortcode('profilecounts_conm', 'all_profile_counts');
function all_profile_counts($atts) { 
     $metakey = shortcode_atts( array('metakey' => 'None'), $atts );
     $metavalue = shortcode_atts( array('metavalue' => 'None'), $atts );
     $franchisees_co = count( get_users(array('meta_key' => $metakey['metakey'], 'meta_value' => $metavalue['metavalue'], 'role' => 'franchisee_nm', ) ) );
     $franchisees_nm = count( get_users(array('meta_key' => $metakey['metakey'], 'meta_value' => $metavalue['metavalue'], 'role' => 'franchisee_co', ) ) );
return round($franchisees_co+$franchisees_nm);
} 

Try this:

function profile_counts($atts) {
    $atts = shortcode_atts( array(
        'metakey'   => '',
        'metavalue' => '',
        'userrole'  => '',
    ), $atts );

    $user_ids = get_users( array(
        'meta_key'    => $atts['metakey'],
        'meta_value'  => $atts['metavalue'],
        'role__in'    => wp_parse_list( $atts['userrole'] ),
        'fields'      => 'ID',  // retrieve just the IDs
        'count_total' => false, // no need for FOUND_ROWS()
    ) );

    return count( $user_ids );
}

Important points:

• For multiple roles, you can use the role__in parameter.

• You only need to call shortcode_atts() once.